Geir Johnsen

Om

Geir Johnsen is a professor in marine biology at the Department of Biology (NTNU at Trondhjem biological station, TBS), Prof II at University Centre on Svalbard (UNIS), and is one of the founding partners in a NTNU spin-off company Ecotone using new optical techniques for mapping and monitoring the marine environment. He is a key scientist in the Centre of excellence (CeO) "Autonomous Marine Operations and Systems (AMOS) using enabling technology for marine ecological studies.

He has been at 1 years research stays at University of California at Santa Barbara (1992-93) , Curtin University, Perth, Australia (2010-11) and University of Hawaii at Manoa, Honolulu (2018-19).

Adviser for 48 MSc and 17 PhD students graduated. Currently he advises 7 PhD candidates and 2 post docs. He have published >140 papers in international scientific journals and been a co-editor for the books "Ecosystem Barents Sea" (Tapir Academic Press, 2009), Phytoplankton pigments: Updates on Characterization, Chemotaxonomy and Applications in Oceanography (Cambridge University Press, 2011) and “Life and Light in the Dead of Night” (Springer-Nature, published end of March 2020).

Research areas

Marine ecology and biodiversity in temperate, tropical and arctic regions
Bio-optics
Photosynthesis and eco-physiology in phytoplankton, ice algae and macroalgae
Pigment chemotaxonomy, light harvesting and photo-protective function
Underwater robotics and sensor development for in situ identification of organisms
Mapping and monitoring of bio-geo-chemical objects of interest in the marine environment
Polar night marine ecology
Photo-biology - Light as a cue of light

Publikasjoner

2026

Osanen, Janina Emilia; Moreira Fragoso, Glaucia; Johnsen, Geir. (2026) Use of novel optical and imaging technologies for the study of phytoplankton and sea ice algal dynamics across spatial and temporal scales. Norges teknisk-naturvitenskapelige universitet
Doktoravhandling
Paiba Garcia, Laura Catherine; Perrin, Sam Wenaas; Johnsen, Geir; Finstad, Anders Gravbrøt; Bakken, Torkild. (2026) Application of an integrated Species Distribution Model (iSDM) for deep-sea marine habitats: Knowledge gaps in the Norwegian extended continental shelf. Ecological Informatics
Vitenskapelig artikkel
Osanen, Janina Emilia; Lange, Benjamin Allen; Campbell, Karley; Johnsen, Geir; Günzel, Leonard Florian Tom; Moreira Fragoso, Glaucia. (2026) Two-platform approach to mapping Arctic sea ice algal aggregates using underwater hyperspectral imaging. Elementa: Science of the Anthropocene
Vitenskapelig artikkel
Nevstad, Malin Bø; Bakken, Torkild; Løvås, Håvard Snefjellå; Hancke, Kasper; Johansen, Tor Arne; Johnsen, Geir. (2026) Hyperspectral Imaging of Seagrass and Macroalgae Using Uncrewed Aerial and Surface Vehicles for Coastal Habitat Mapping. Remote Sensing
Vitenskapelig artikkel
Summers, Natalie Maria; Bremnes, Jens Einar; Liu, Hongbo; Løvås, Håvard Snefjellå; Moreira Fragoso, Glaucia; Johnsen, Geir. (2026) Assessing Arctic under sea-ice light regimes and ice algal bio-optical properties using ROV-based hyperspectral imaging. Polar Biology
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Hama, Nalia; Snijder, Elisabeth; Aldridge, David; Borrero Santiago, Ana Rocio; Broch, Ole Jacob; Johnsen, Geir; Olsen, Yngvar; Hatlebakk, Maja Karoline Viddal. (2026) The influence of environmental factors and phytoplankton blooms on cyphonautes larvae abundance and bryozoan colony development at a kelp farm in central Norway. Marine Environmental Research
Vitenskapelig artikkel

2025

Paiba Garcia, Laura Catherine; Johnsen, Geir; Perrin, Sam Wenaas; Bakken, Torkild. (2025) Open‐Source Marine Biodiversity Data Quality in the Norwegian Sea Spanning 149 Years: Knowledge Gaps in the Deep‐Sea Mining Opening Area. Ecology and Evolution
Vitenskapelig artikkel
Berge, Jørgen; Bakken, Torkild; Heggland, Kristin; Sneli, Jon-Arne; Ødegård, Øyvind; Ingulstad, Mats; Thun, Terje; Johnsen, Geir. (2025) Exploring Climate Change, Geopolitics, Marine Archeology, and Ecology in the Arctic Ocean Through Wood-Boring Bivalves. Oceanography
Vitenskapelig artikkel
Neves, Luiza S.; Smeby, Kristin; Broch, Ole Jacob; Johnsen, Geir; Ardelan, Murat van; Skjermo, Jorunn. (2025) Particulate and dissolved organic carbon losses in high latitude seaweed farms. Science of the Total Environment
Vitenskapelig artikkel
Jones, Alun; Utne, Ingrid Bouwer; Johnsen, Geir. (2025) Towards ecological integration into socio-technical risk assessment: A multidisciplinary system-theoretic approach. Ocean Engineering
Vitenskapelig artikkel
Günzel, Leonard Florian Tom; Osanen, Janina Emilia; Løvås, Håvard Snefjellå; Johnsen, Geir; Ortiz, Alberto García; Ludvigsen, Martin. (2025) Using Underwater Hyperspectral Imaging to Increase Feature Detection and Improve Under-Ice Navigation. IEEE Underwater Technology (UT)
Vitenskapelig artikkel

2024

Schartmüller, Bernhard; Mckee, David; Berge, Jørgen; Johnsen, Geir. (2024) Calibration verification of an underwater hyperspectral imaging push broom instrument to measure light in absolute units and field demonstration. Applied Optics
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Dallolio, Alberto; Grant, Stephen Denis; Garrett, Joseph Landon; Ellingsen, Ingrid Helene; Johnsen, Geir; Johansen, Tor Arne. (2024) The Role of Rapid Changes in Weather on Phytoplankton Spring Bloom Dynamics Captured by an Autonomous Uncrewed Surface Vehicle. Earth and Space Science
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Last, Kim; Cohen, Jonathan H.; McKee, David. (2024) Light in polar regions.
Faglig kapittel
Ingulstad, Mats; Bakken, Torkild; Ellefmo, Steinar Løve; Johnsen, Geir; Hagspiel, Verena. (2024) Villedende om hypotetiske havbunnsmineraler?. Dagens næringsliv
Kommentar
Mo-Bjørkelund, Tore; Majaneva, Sanna Kristiina; Moreira Fragoso, Glaucia; Johnsen, Geir; Ludvigsen, Martin. (2024) Multi-vehicle adaptive 3D mapping for targeted ocean sampling. PLOS ONE
Vitenskapelig artikkel
Faltynkova, Andrea; Deschenes, Catherine; Zolich, Artur; Wagner, Martin; Johansen, Tor Arne; Johnsen, Geir. (2024) Use of an uncrewed surface vehicle and near infrared hyperspectral imaging for sampling and analysis of aquatic microplastics. Marine Pollution Bulletin
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Dallolio, Alberto; Grant, Stephen Denis; Garrett, Joseph Landon; Ellingsen, Ingrid Helene; Johnsen, Geir; Johansen, Tor Arne. (2024) The Role of Rapid Changes in Weather on Phytoplankton Spring Bloom Dynamics From Mid-Norway Using Multiple Observational Platforms. Journal of Geophysical Research (JGR): Oceans
Vitenskapelig artikkel
Liu, Hongbo; Summers, Natalie Maria; Chen, Yi-Chun; Løvås, Håvard Snefjellå; Johnsen, Geir; Koestner, Daniel Warren; Sætre, Camilla; Hamre, Børge. (2024) Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments. Optics Express
Vitenskapelig artikkel
Overrein, Martin Molberg; Tinn, Phil; Aldridge, David; Johnsen, Geir; Moreira Fragoso, Glaucia. (2024) Biomass estimations of cultivated kelp using underwater RGB images from a mini-ROV and computer vision approaches. Frontiers in Marine Science
Vitenskapelig artikkel

2023

Schartmuller, Bernhard; Anderson, Philip; Mckee, David; Connan-McGinty, Stacey; Kopec, Tomasz Piotr; Daase, Malin Hildegard Elisabeth; Johnsen, Geir; Berge, Jørgen. (2023) Development and calibration of a high dynamic range and autonomous ocean-light instrument to measure sub-surface profiles in ice-covered waters. Applied Optics
Vitenskapelig artikkel
Williamson, David Roddan; Moreira Fragoso, Glaucia; Majaneva, Sanna Kristiina; Dallolio, Alberto; Halvorsen, Daniel Ørnes; Hasler, Oliver Kevin; Oudijk, Adriënne Esmeralda; Langer, Dennis David; Johansen, Tor Arne; Johnsen, Geir; Stahl, Annette; Ludvigsen, Martin; Garrett, Joseph Landon. (2023) Monitoring Algal Blooms with Complementary Sensors on Multiple Spatial and Temporal Scales. Oceanography
Vitenskapelig artikkel
Summers, Natalie Maria; Moreira Fragoso, Glaucia; Johnsen, Geir. (2023) Photophysiologically active green, red, and brown macroalgae living in the Arctic Polar Night. Scientific Reports
Vitenskapelig artikkel
Deschenes, C; Zolich, Artur; Wagner, Martin; Johnsen, Geir; Johansen, Tor Arne; Faltynkova, Andrea. (2023) Unmanned vehicle and hyperspectral imager for a more rapid microplastics sampling and analysis. OCEANS
Vitenskapelig artikkel
oudijk, AE; Johansen, Tor Arne; Johnsen, Geir; Alver, Morten Omholt. (2023) Simulating Hyperspectral Datacubes for Ocean Color: A Foundation for Phytoplankton Recognition in Spectral Signatures. OCEANS
Vitenskapelig artikkel
Grant, Stephen Denis; Johnsen, Geir; Mckee, David; Zolich, Artur Piotr; Cohen, Jonathan H.. (2023) Spectral and RGB analysis of the light climate and its ecological impacts using an all-sky camera system in the Arctic. Applied Optics
Vitenskapelig artikkel
Gerland, Sebastian; Ingvaldsen, Randi Brunvær; Reigstad, Marit; Sundfjord, Arild; Bogstad, Bjarte; Chierici, Melissa; Hop, Haakon; Renaud, Paul E.; Smedsrud, Lars Henrik; Stige, Leif Christian; Årthun, Marius; Berge, Jørgen; Bluhm, Bodil A.; Borgå, Katrine; Bratbak, Gunnar; Divine, Dmitry V; Eldevik, Tor; Eriksen, Elena; Fer, Ilker; Fransson, Agneta; Gradinger, Rolf; Granskog, Mats A.; Haug, Tore; Husum, Katrine; Johnsen, Geir; Jonassen, Marius O.; Jørgensen, Lis Lindal; Kristiansen, Svein; Larsen, Aud; Lien, Vidar S.; Lind, Sigrid; Lindstrøm, Ulf; Mauritzen, Cecilie; Melsom, Arne; Mernild, Sebastian H.; Müller, Malte; Nilsen, Frank; Primicerio, Raul; Søreide, Janne E.; van der Meeren, Gro I.; Wassmann, Paul. (2023) Still Arctic? — The changing Barents Sea. Elementa: Science of the Anthropocene
Vitenskapelig oversiktsartikkel
Bakken, Sivert; Luis, Kelly; Johnsen, Geir; Johansen, Tor Arne. (2023) Evaluating hyperspectral Secchi depth retrieval through hybrid modeling and regression. Workshop on Hyperspectral Image and Signal Processing, Evolution in Remote Sensing
Vitenskapelig artikkel
Bakken, Sivert; Henriksen, Marie Bøe; Birkeland, Roger; Langer, Dennis David; Oudijk, Adriënne Esmeralda; Berg, Simen; Pursley, Yeshi Jampel; Garrett, Joseph Landon; Gran-Jansen, Fredrik; Honoré-Livermore, Evelyn; Grøtte, Mariusz Eivind Santora; Kristiansen, Bjørn Andreas; Orlandic, Milica; Gader, Paul; Sørensen, Asgeir Johan; Sigernes, Fred; Johnsen, Geir; Johansen, Tor Arne. (2023) HYPSO-1 CubeSat: First Images and In-Orbit Characterization. Remote Sensing
Vitenskapelig artikkel

2022

Summers, Natalie; Johnsen, Geir; Mogstad, Aksel Alstad; Løvås, Håvard; Moreira Fragoso, Glaucia; Berge, Jørgen. (2022) Underwater Hyperspectral Imaging of Arctic Macroalgal Habitats during the Polar Night Using a Novel Mini-ROV-UHI Portable System. Remote Sensing
Vitenskapelig artikkel
Zolich, Artur Piotr; Faltynkova, Andrea; Johnsen, Geir; Johansen, Tor Arne. (2022) Portable Catamaran Drone - an uncrewed sampling vehicle for micro-plastics and aquaculture research.
Vitenskapelig kapittel
Mogstad, Aksel Alstad; Løvås, Håvard; Sture, Øystein; Johnsen, Geir; Ludvigsen, Martin. (2022) Remote Sensing of the Tautra Ridge: An Overview of the World’s Shallowest Cold-Water Coral Reefs. Frontiers in Marine Science
Vitenskapelig artikkel
Oudijk, Esmée; Hasler, Oliver Kevin; Øveraas, Henning; Marty, Sabine; Williamson, David Roddan; Svendsen, Torbjørn Karl; Berg, Simen; Birkeland, Roger; Halvorsen, Daniel Ørnes; Bakken, Sivert; Henriksen, Marie Bøe; Alver, Morten; Johnsen, Geir; Johansen, Tor Arne; Stahl, Annette; Kvaløy, Pål; Dallolio, Alberto; Majaneva, Sanna; Moreira Fragoso, Glaucia; Garrett, Joseph. (2022) Campaign For Hyperspectral Data Validation In North Atlantic Coastal Waters. Workshop on Hyperspectral Image and Signal Processing, Evolution in Remote Sensing
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Davies, Emlyn John; Fossum, Trygve Olav; Ullgren, Jenny; Majaneva, Sanna; Aberle-Malzahn, Nicole; Ludvigsen, Martin; Johnsen, Geir. (2022) Contrasting phytoplankton-zooplankton distributions observed through autonomous platforms, in-situ optical sensors and discrete sampling. PLOS ONE
Vitenskapelig artikkel
Connan-McGinty, Stacey; Banas, Neil S.; Berge, Jørgen; Cottier, Finlo Robert; Grant, Stephen; Johnsen, Geir; Kopec, Tomasz Piotr; Porter, Marie; Mckee, David. (2022) Midnight Sun to Polar Night: A Model of Seasonal Light in the Barents Sea. Journal of Advances in Modeling Earth Systems
Vitenskapelig artikkel
Dona, Angela; Evertsen, Jussi; Johnsen, Geir. (2022) The role of parapodia and lack of photoacclimation in kleptoplasts of the sacoglossan sea slug Plakobranchus ocellatus. Coral reefs
Vitenskapelig artikkel

2021

Ringvold, Halldis; Taite, Morag; Allcock, A. Louise; Vecchione, Michael; Péan, Michel; Sandulli, Roberto; Johnsen, Geir; Fjellheim, Arne; Bakke, Snorre; Sannæs, Hanne; Synnes, Ann-Elin; Coronel, José; Hansen, Martin; Olejar, Peter; Eliassen, Geir; Eliassen, Anita; Klungland, Karl. (2021) In situ recordings of large gelatinous spheres from NE Atlantic, and the first genetic confirmation of egg mass of Illex coindetii (Vérany, 1839) (Cephalopoda, Mollusca). Scientific Reports
Vitenskapelig artikkel
Bazilchuk, Nancy Reney; Berge, Jørgen; Johnsen, Geir. (2021) Lysforurensning I Arktis kan ha ødelagt forskningsresultater. Gemini.no
Populærvitenskapelig artikkel
Cardwell, CR; Berge, Jørgen; Johnsen, Geir. (2021) Arctic voyage shines light on some cold, hard truths. The Herald, UK
Populærvitenskapelig artikkel
Bazilchuk, Nancy Reney; Stahl, Annette; Johnsen, Geir; Saad, Aya; Thu, Maren; Nøland, Annecken; Aberle-Malzahn, Nicole. (2021) Sporhunden som lukter mikroalger. Gemini.no
Populærvitenskapelig artikkel
Faltynkova, Andrea; Johnsen, Geir; Wagner, Martin. (2021) Hyperspectral imaging as an emerging tool to analyze microplastics: A systematic review and recommendations for future development. Microplastics and Nanoplastics
Vitenskapelig oversiktsartikkel
Horni, K; Sørensen, Asgeir Johan; Johnsen, Geir; Ludvigsen, Martin. (2021) Internasjonalt forskningsmiljø dykker i Mjøsa etter at Oppland Arbeiderblad skrev om forurensning. Oppland arbeiderblad
Populærvitenskapelig artikkel
Løvås, Håvard; Mogstad, Aksel Alstad; Sørensen, Asgeir Johan; Johnsen, Geir. (2021) A Methodology for Consistent Georegistration in Underwater Hyperspectral Imaging. IEEE Journal of Oceanic Engineering
Vitenskapelig artikkel
Cohen, Jonathan H.; Last, Kim; Charpentier, Corie L.; Cottier, Finlo; Daase, Malin; Hobbs, Laura; Johnsen, Geir; Berge, Jørgen. (2021) Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night. PLoS Biology
Vitenskapelig artikkel
Johnsen, Geir; Zolich, Artur; Grant, Stephen; Bjørgum, Rune; Cohen, Jonathan H.; Mckee, David; Kopec, Tomasz Piotr; Vogedes, Daniel Ludwig; Berge, Jorgen. (2021) All-sky camera system providing high temporal resolution annual time series of irradiance in the arctic. Applied Optics
Vitenskapelig artikkel
Bakken, Sivert; Johnsen, Geir; Johansen, Tor Arne. (2021) Analysis and Model Development of Direct Hyperspectral Chlorophyll-A Estimation for Remote Sensing Satellites. Workshop on Hyperspectral Image and Signal Processing, Evolution in Remote Sensing
Vitenskapelig artikkel
Geoffroy, Maxime; Langbehn, Tom Jasper; Priou, Pierre; Varpe, Øystein; Johnsen, Geir; Bris, Arnault Le; Fisher, Jonathan A. D.; Daase, Malin; Mckee, David; Cohen, Jonathan H.; Berge, Jørgen. (2021) Pelagic organisms avoid white, blue, and red artificial light from scientific instruments. Scientific Reports
Vitenskapelig artikkel

2020

Ramirez-Llodra, Eva; Hilário, Ana; Paulsen, Emil; Costa, Carolina; Bakken, Torkild; Johnsen, Geir; Rapp, Hans Tore. (2020) Benthic Communities on the Mohn’s Treasure Mound: Implications for Management of Seabed Mining in the Arctic Mid-Ocean Ridge. Frontiers in Marine Science
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Johnsen, Geir; Chauton, Matilde Skogen; Cottier, Finlo Robert; Ellingsen, Ingrid H.. (2020) Phytoplankton community succession and dynamics using optical approaches. Continental Shelf Research
Vitenskapelig artikkel
Berge, Jørgen; Geoffroy, Maxime; Daase, Malin; Cottier, Finlo Robert; Priou, Pierre; Cohen, Jonathan H.; Johnsen, Geir; Mckee, David; Kostakis, Ina; Renaud, Paul Eric; Vogedes, Daniel Ludwig; Anderson, Philip J.; Last, Kim S.; Gauthier, Stephane. (2020) Artificial light during the polar night disrupts Arctic fish and zooplankton behavior down to 200 m depth. Communications Biology
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Cohen, Jonathan H.. (2020) Introduction.
Innledning i antologi
Cohen, Jonathan H.; Berge, Jørgen; Moline, Mark A.; Johnsen, Geir; Zolich, Artur Piotr. (2020) Light in the Polar Night.
Vitenskapelig kapittel
Mogstad, Aksel Alstad; Ødegård, Øyvind; Nornes, Stein Melvær; Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen. (2020) Mapping the Historical Shipwreck Figaro in the High Arctic Using Underwater Sensor-Carrying Robots. Remote Sensing
Vitenskapelig artikkel
Johnsen, Geir; Leu, Eva; Gradinger, Rolf. (2020) Marine Micro- and Macroalgae in the Polar Night.
Vitenskapelig kapittel
Berge, Jørgen; Johnsen, Geir. (2020) Life and Light at the Dead of Night.
Vitenskapelig kapittel
Johnsen, Geir; Mogstad, Aksel Alstad; Berge, Jørgen; Cohen, Jonathan H.. (2020) Operative Habitat Mapping and Monitoring in the Polar Night.
Vitenskapelig kapittel
Saad, Aya; Stahl, Annette; Våge, Andreas; Davies, Emlyn John; Nordam, Tor; Aberle-Malzahn, Nicole; Ludvigsen, Martin; Johnsen, Geir; Sousa, João; Rajan, Kanna. (2020) Advancing Ocean Observation with an AI-driven Mobile Robotic Explorer. Oceanography
Vitenskapelig artikkel

2019

Kauko, Hanna Maria; Pavlov, Alexey; Johnsen, Geir; Granskog, Mats; Peeken, Ilka; Assmy, Philipp. (2019) Photoacclimation state of an Arctic underice phytoplankton bloom. Journal of Geophysical Research (JGR): Oceans
Vitenskapelig artikkel
Bazilchuk, Nancy Reney; Fossum, Trygve Olav; Moreira Fragoso, Glaucia; Ludvigsen, Martin; Johnsen, Geir. (2019) Smart undervannsrobot leter etter plankton. Av N Bazilchuk. Forskning.no. Angående NTNU Entice prosjekt publisert i Science Robotics. Forskning.no
Populærvitenskapelig artikkel
Pavlov, Alexey K.; Leu, Eva; Hanelt, Dieter; Bartsch, Inka; Karsten, Ulf; Hudson, Stephen; Gallet, Jean-Charles; Cottier, Finlo Robert; Cohen, Jonathan H.; Berge, Jørgen; Johnsen, Geir; Maturilli, Marion; Kowalczuk, Piotr; Sagan, Slawomir; Meler, Justyna; Granskog, Mats. (2019) The Underwater Light Climate in Kongsfjorden and Its Ecological Implications.
Vitenskapelig kapittel
Moreira Fragoso, Glaucia; Davies, Emlyn John; Ellingsen, Ingrid H.; Chauton, Matilde Skogen; Fossum, Trygve Olav; Ludvigsen, Martin; Steinhovden, Kristine; Rajan, Kanna; Johnsen, Geir. (2019) Physical controls on phytoplankton size structure, photophysiology and suspended particles in a Norwegian biological hotspot. Progress in Oceanography
Vitenskapelig artikkel
Mogstad, Aksel Alstad; Johnsen, Geir; Ludvigsen, Martin. (2019) Shallow-Water Habitat Mapping using Underwater Hyperspectral Imaging from an Unmanned Surface Vehicle: A Pilot Study. Remote Sensing
Vitenskapelig artikkel
Kleiven, Wanda; Johnsen, Geir; Ardelan, Murat Van. (2019) Sea surface microlayer and elemental composition in phaeo-, chloro-, and rhodophytes in winter and spring. Journal of Phycology
Vitenskapelig artikkel
Fossum, Trygve Olav; Moreira Fragoso, Glaucia; Davies, Emlyn John; Ullgren, Jenny; Mendes, Renato; Johnsen, Geir; Ellingsen, Ingrid H.; Eidsvik, Jo; Ludvigsen, Martin; Rajan, Kanna. (2019) Toward adaptive robotic sampling of phytoplankton in the coastal ocean. Science robotics
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Poulton, Alex James; Pratt, Nicola Jane; Johnsen, Geir; Purdie, Duncan Alastair. (2019) Trait-based analysis of subpolar North Atlantic phytoplankton and plastidic ciliate communities using automated flow cytometer. Limnology and Oceanography
Vitenskapelig artikkel

2018

Ødegård, Øyvind; Mogstad, Aksel Alstad; Johnsen, Geir; Sørensen, Asgeir Johan; Ludvigsen, Martin. (2018) Underwater hyperspectral imaging: a new tool for marine archaeology. Applied Optics
Vitenskapelig artikkel
Dumke, Ines; Purser, Autun; Marcon, Yann; Nornes, Stein Melvær; Johnsen, Geir; Ludvigsen, Martin; Søreide, Fredrik. (2018) Underwater hyperspectral imaging as an in situ taxonomic tool for deep-sea megafauna. Scientific Reports
Vitenskapelig artikkel
Kauko, Hanna Maria; Olsen, Lasse Mork; Duarte, Pedro; Peeken, Ilka; Granskog, Mats A.; Johnsen, Geir; Fernández-Méndez, Mar; Pavlov, Alexey; Mundy, Christopher John; Assmy, Philipp. (2018) Algal colonization of young arctic sea ice in spring. Frontiers in Marine Science
Vitenskapelig artikkel
Johnsen, Geir; Norli, Marit; Moline, Mark A.; Robbins, Ian; von Quillfeldt, Cecilie; Sørensen, Kai; Cottier, Finlo Robert; Berge, Jørgen. (2018) The advective origin of an under-ice spring bloom in the Arctic Ocean using multiple observational platforms. Polar Biology
Vitenskapelig artikkel
Dumke, Ines; Nornes, Stein Melvær; Purser, Autun; Marcon, Yann; Ludvigsen, Martin; Ellefmo, Steinar Løve; Johnsen, Geir; Søreide, Fredrik. (2018) First hyperspectral imaging survey of the deep seafloor: High-resolution mapping of manganese nodules. Remote Sensing of Environment
Vitenskapelig artikkel
Zolich, Artur Piotr; Torre, Pedro R. De La; Rodwell, Shane; Geoffroy, Maxime; Johnsen, Geir; Berge, Jørgen. (2018) An ice-tethered buoy for fish and plankton research.
Vitenskapelig kapittel
Fossum, Trygve Olav; Eidsvik, Jo; Ellingsen, Ingrid H.; Alver, Morten; Moreira Fragoso, Glaucia; Johnsen, Geir; Mendes, Renato; Ludvigsen, Martin; Rajan, Kanna. (2018) Information-driven robotic sampling in the coastal ocean. Journal of Field Robotics (JFR)
Vitenskapelig artikkel
Geoffroy, Maxime; Berge, Jørgen; Majaneva, Sanna Kristiina; Johnsen, Geir; Langbehn, Tom; Cottier, Finlo Robert; Mogstad, Aksel Alstad; Zolich, Artur Piotr; Last, Kim. (2018) Increased occurrence of the jellyfish Periphylla periphylla in the European high Arctic. Polar Biology
Vitenskapelig artikkel
Gabrielsen, Tove M.; Johnsen, Geir. (2018) Skogen på Svalbard. Svalbardposten
Populærvitenskapelig artikkel
Dumke, Ines; Ludvigsen, Martin; Ellefmo, Steinar Løve; Søreide, Fredrik; Johnsen, Geir; Murton, Bramley J.. (2018) Underwater Hyperspectral Imaging Using a Stationary Platform in the Trans-Atlantic Geotraverse Hydrothermal Field. IEEE Transactions on Geoscience and Remote Sensing
Vitenskapelig artikkel
Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H.; Torre, Pedro R. De La; Nornes, Stein Melvær; Singh, Hanumant; Sørensen, Asgeir Johan; Daase, Malin; Johnsen, Geir. (2018) Use of an autonomous surface vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance. Science Advances
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Poulton, Alex J.; Yashayaev, Igor M.; Head, Erica J.H.; Johnsen, Geir; Purdie, Duncan A.. (2018) Diatom biogeography from the Labrador Sea revealed through a trait-based approach. Frontiers in Marine Science
Vitenskapelig artikkel
Liefmann, Stephanie; Järnegren, Johanna; Johnsen, Geir; Murray, Fiona. (2018) Eco-physiological responses of cold-water soft corals to anthropogenic sedimentation and particle shape. Journal of Experimental Marine Biology and Ecology
Vitenskapelig artikkel

2017

Kauko, Hanna Maria; Taskjelle, Torbjørn; Assmy, Philipp; Pavlov, Alexey K.; Mundy, C.J.; Duarte, Pedro; Fernández-Méndez, Mar; Olsen, Lasse Mork; Hudson, Stephen R.; Johnsen, Geir; Elliott, Ashley; Wang, Feiyue; Granskog, Mats A.. (2017) Windows in Arctic sea ice: light transmission and ice algae in a refrozen lead. Journal of Geophysical Research (JGR): Biogeosciences
Vitenskapelig artikkel
Mogstad, Aksel Alstad; Johnsen, Geir. (2017) Spectral characteristics of coralline algae: a multi-instrumental approach, with emphasis on underwater hyperspectral imaging. Applied Optics
Vitenskapelig artikkel
Ostaszewska, Kaja; Balazy, Piotr; Berge, Jørgen; Johnsen, Geir; Staven, Robert. (2017) Seabirds during Arctic Polar Night: underwater observations from Svalbard archipelago, Norway. Waterbirds (De Leon Springs, Fla.)
Vitenskapelig artikkel
Assmy, Philipp; Fernández-Méndez, Mar; Duarte, Pedro; Meyer, Amelie; Randelhoff, Achim; Mundy, Christopher John; Olsen, Lasse Mork; Kauko, Hanna M.; Bailey, Allison; Chierici, Melissa; Cohen, Lana; Doulgeris, Anthony Paul; Ehn, Jens K.; Fransson, Agneta; Gerland, Sebastian; Hop, Haakon; Hudson, Stephen R.; Hughes, Nick; Itkin, Polona; Johnsen, Geir; King, Jennifer A.; Koch, Boris P.; Koenig, Zoe; Kwasniewski, Slawomir; Laney, Samuel R.; Nikolaus, Marcel; Pavlov, Alexey K.; Polashenski, Christopher M.; Provost, Christine; Rösel, Anja; Sandbu, Marthe; Spreen, Gunnar; Smedsrud, Lars H.; Sundfjord, Arild; Taskjelle, Torbjørn; Tatarek, Agnieszka; Wiktor, Josef; Wagner, Penelope Mae; Wold, Anette; Steen, Harald; Granskog, Mats A.. (2017) Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ic. Scientific Reports
Vitenskapelig artikkel

2016

Donahue, Michelle; Berge, Jørgen; Johnsen, Geir; Ødegård, Øyvind. (2016) The age of humans - living in the anthropocene - "Termites of the sea" found munching wood near Arctic shipwrecks. Smithsonian
Populærvitenskapelig artikkel
Førde, Henny; Forbord, Silje; Handå, Aleksander; Fossberg, Julia; Arff, Johanne; Johnsen, Geir; Reitan, Kjell Inge. (2016) Development of bryozoan fouling on cultivated kelp (Saccharina latissima) in Norway. Journal of Applied Phycology
Vitenskapelig artikkel
Berge, Jørgen; Renaud, Paul E.; Johnsen, Geir; Darnis, Gerald; Geoffroy, Maxime; Daase, Malin; Kwasniewski, S; Draganska, K; Cottier, Finlo Robert; Falk-Petersen, Stig. (2016) I grenselandet (mellom Tull og Thule). Svalbardposten
Populærvitenskapelig artikkel
Haugstad, Tor; Erdal, Ivar; Johnsen, Geir; Sørensen, Asgeir Johan; Fjærvik, Nils. (2016) Gründerne mener dette kameraet kan bli det nye ekkoloddet – Ecotone er kandidat til TU Tech Award. Teknisk Ukeblad
Populærvitenskapelig artikkel
Aarskog, Karine Nigar; Berge, Jørgen; Johnsen, Geir; Sørensen, Asgeir Johan. (2016) Et stort løft for arktisk forskning (NTNU & UiT). Universitetet i Tromsø
Fagartikkel
Haudemann-Andersen, Jørn; Lystad, M S; Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen. (2016) Blå lys i det kalde dyp. NRK Trøndelag, Nyheter
Populærvitenskapelig artikkel
Bazilchuk, Nancy Reney; Leite, Stein Roar; Johnsen, Geir; Kjeken, John; Sørensen, Asgeir Johan; Ludvigsen, Martin. (2016) Bomber og buss på havbunnen. Gemini
Populærvitenskapelig artikkel
Johnsen, Geir. (2016) Yrende liv i Isfjorden. Svalbardposten
Populærvitenskapelig artikkel
Krüger, Frida Jørstad; Johnsen, Geir; Kjeken, John; Ludvigsen, Martin. (2016) Gammel buss ble korallrev. NRK Viten
Populærvitenskapelig artikkel
Lervik, Frank; Johnsen, Geir; Ludvigsen, Martin; Kjeken, John. (2016) Det ligger flere busser der. Adresseavisen
Populærvitenskapelig artikkel
Bjørgan, Espen Halvorsen; Johnsen, Geir; Kjeken, Jon; Ludvigsen, Martin. (2016) Fant buss på 600 m dybde. Adresseavisen
Populærvitenskapelig artikkel
Berge, Jørgen; Falk-Petersen, Stig; Renaud, Paul E.; Daase, Malin; Geoffroy, Maxime; Johnsen, Geir. (2016) En reise mot Ultima Thule. Svalbardposten
Populærvitenskapelig artikkel
Bazilchuk, Nancy Reney; Johnsen, Geir; Berge, Jørgen; Ludvigsen, Martin; Sørensen, Asgeir Johan; Ødegård, Øyvind. (2016) Mørkets fyrster, varulver og Indiana Jones. Gemini
Populærvitenskapelig artikkel
Kokkegård, Hanne; Johnsen, Geir; Ludvigsen, Martin; Torre, Pedro De La. (2016) Vitenskab - Bomber fra 2 verdenskrig danner koralrev på 600 m dybde. Danmarks radio
Populærvitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir. (2016) Mørkets fyrster med påskrudd lys. Svalbardposten
Populærvitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Ødegård, Øyvind. (2016) Mark spiser opp vrak på havbunnen. Fiskaren
Populærvitenskapelig artikkel
Bondø, Tor-Hartvig; Johnsen, Geir; Berge, Jørgen. (2016) Fant yrende liv i polarnatta. VG : Verdens gang
Populærvitenskapelig artikkel
Johnsen, Geir; Ludvigsen, Martin; Sørensen, Asgeir Johan; Aas, Lars Martin Sandvik. (2016) The use of underwater hyperspectral imaging deployed on remotely operated vehicle – methods and applications. IFAC-PapersOnLine
Vitenskapelig artikkel
Cronin, Heather; Cohen, Jonathan H.; Berge, Jørgen; Johnsen, Geir; Moline, Mark A.. (2016) Bioluminescence as an ecological factor during high Arctic polar night. Scientific Reports
Vitenskapelig artikkel
Berge, Jørgen; Geoffroy, Maxime; Johnsen, Geir; Cottier, Finlo Robert; Bluhm, Bodil; Vogedes, Daniel Ludwig. (2016) Ice-tethered observational platforms in the Arctic Ocean pack ice. IFAC-PapersOnLine
Vitenskapelig artikkel

2015

Cohen, Jonathan H.; Berge, Jørgen; Moline, Mark A.; Sørensen, Asgeir Johan; Last, Kim; Falk-Petersen, Stig; Renaud, Paul; Leu, Eva; Grenvald, Julie Cornelius; Cottier, Finlo; Cronin, Heather; Menze, Sebastian; Norgren, Petter; Varpe, Øystein; Daase, Malin; Darnis, Gérald; Johnsen, Geir. (2015) Is ambient light during the high Arctic polar night sufficient to act as a visual cue for zooplankton?. PLOS ONE
Vitenskapelig artikkel
Nilssen, Ingunn; Ødegård, Øyvind; Sørensen, Asgeir Johan; Johnsen, Geir; Moline, Mark A.; Berge, Jørgen. (2015) Integrated environmental mapping and monitoring, a methodological approach to optimise knowledge gathering and sampling strategy. Marine Pollution Bulletin
Vitenskapelig artikkel
Berge, Jørgen; Renaud, Paul; Darnis, Gérald; Cottier, Finlo; Last, Kim; Gabrielsen, Tove M.; Johnsen, Geir; Seuthe, Lena; Weslawski, Jan Marcin; Leu, Eva; Moline, Mark A.; Nahrgang, Jasmine; Søreide, Janne; Varpe, Øystein; Lønne, Ole Jørgen; Daase, Malin; Falk-Petersen, Stig. (2015) In the dark: a review of ecosystem processes during the Arctic polar night. Progress in Oceanography
Vitenskapelig artikkel
Berge, Jørgen; Daase, Malin; Renaud, Paul; Ambrose, William G. Jr.; Darnis, Gérald; Last, Kim S; Leu, Eva; Cohen, Jonathan H.; Johnsen, Geir; Moline, Mark A.; Cottier, Finlo; Varpe, Øystein; Shunatova, Natalia; Morata, Nathalie; Balazy, Piotr; Massabuau, Jean Charles; Falk-Petersen, Stig; Kosobokova, Ksenia; Hoppe, Clara J.M.; Weslawski, Jan Marcin; Kuklinski, Piotr; Legeżyńska, Joanna; Nikishina, Daria; Cusa, Marine; Kedra, Monika; Wlodarska-Kowalczuk, Maria; Vogedes, Daniel Ludwig; Camus, Lionel; Tran, Damien; Michaud, Emma; Gabrielsen, Tove M.; Granovitch, Andrei; Gonchar, Anya; Krapp, Rupert; Callesen, Trine A.. (2015) Unexpected levels of biological activity during the polar night offer new perspectives on a warming Arctic. Current Biology
Vitenskapelig artikkel
Ludvigsen, Martin; Thorsnes, Terje; Hansen, Roy Edgar; Sørensen, Asgeir Johan; Johnsen, Geir; Lågstad, Petter Arthur; Ødegård, Øyvind; Candeloro, Mauro; Nornes, Stein Melvær; Malmquist, Christian. (2015) Underwater vehicles for environmental management in coastal areas.
Vitenskapelig kapittel
Nilssen, Ingunn; Santos, Francisco Dos; Coutinho, Ricardo; Gomes, Natalia; Cabral, Marcelo M.; Eide, Ingvar; Figueiredo, Marcia AO; Johnsen, Geir; Johnsen, Ståle. (2015) Assessing the potential impact of water-based drill cuttings on deep water calcareous red algae using species specific impact categories and measured oceanographic and discharge data. Marine Environmental Research
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Sørensen, Asgeir Johan; Nilssen, Ingunn. (2015) Enabling technology for Arctic research. Pan European Networks: Science and Techology Magazine
Vitenskapelig oversiktsartikkel
Nilssen, Ingunn; dos, Francisco Santos; Coutinho, Ricardo; Gomes, Natalia; Montenegro, Marcelo Cabral; Eide, Ingvar; Figueiredo, Marcia; Johnsen, Geir; Johnsen, Ståle. (2015) Assessing the potential impact of water-based drill cuttings on deep-water calcareous red algae using species specific impact categories and measured oceanographic and discharge data. Marine Environmental Research
Vitenskapelig artikkel
Rodriguez, Francisco; Garrido, J.L.; Sabrino, C; Johnsen, Geir; Riobo, P; Franco, J; Aamot, Inga; Ramilo, I; Sanz, N; Kremp, Anke. (2015) Divinyl chlorophyll a in the marine eukaryotic protist Alexandrium ostenfeldii (Dinophyceae). Environmental Microbiology
Vitenskapelig artikkel

2014

Ødegård, Øyvind; Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Ekehaug, Stefan; Dukan, Fredrik; Moline, Mark A.. (2014) Managing data from multiple sensors in an interdisciplinary research cruise.
Vitenskapelig kapittel
Cohen, Jonathan; Cronin, Heather; Moline, Mark A.; Berge, Jørgen; Johnsen, Geir; Sørensen, Asgeir Johan. (2014) Are krill eyes useful in the high Arctic polar night?. Ocean Optics
Konferanseabstract
Aamot, Inga; Pokrzywinski, Kaytee; Johnsen, Geir; Berge, Jørgen; Sørensen, Asgeir Johan. (2014) Light Climate and Status of the Photosynthetic Machinery in Macroalgae in the Polar Night. Ocean Optics
Konferanseabstract
Hansen, Ingrid; Pettersen, Ragnhild; Beuchel, Frank; Cochrane, Sabine; Frantzen, marianne; Ekehaug, Stefan; Erdal, Ivar; Johnsen, Geir; Camus, Lionel. (2014) Underwater hyperspectral imaging (UHI) for environmental mapping and monitoring of seabed habitats. Ocean Optics
Konferanseabstract
Nilssen, Ingunn; Ødegård, Øyvind; Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen; Nornes, Stein Melvær; Norgren, Petter; Vieweg, Ireen. (2014) Integrated environmental monitoring; a methodological approach to optimise knowledge gathering and sampling strategy. Ocean Optics
Konferanseabstract
Johnsen, Geir; Ekehaug, Stefan; Hansen, Ingrid; Sørensen, Asgeir Johan. (2014) The use of underwater hyperspectral imaging deployed on remotely operated vehicles to identify, map and monitor bio-geo-chemical objects of interest. Ocean Optics
Konferanseabstract
Nornes, Stein Melvær; Candeloro, Mauro; Ødegård, Øyvind; Johnsen, Geir; Sørensen, Asgeir Johan. (2014) Photomosaic camera as simultaneous data collector and navigation aid on unmanned underwater vehicles. Ocean Optics
Konferanseabstract
Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Lågstad, Petter Arthur; Ødegård, Øyvind. (2014) Scientific Operations Combining ROV and AUV in the Trondheim Fjord. Marine Technology Society journal
Vitenskapelig artikkel
Eldevik, Tor; Reigstad, Marit; Falck, Eva; Gerland, Sebastian; Jentoft, Sissel; Johnsen, Geir; Lindstrøm, Ulf; Rasmussen, Tine Lander; Røed, Lars Petter; Wassmann, Paul. (2014) Arven efter Nansen. Forskningsplan for det sentrale og nordlige Barentshavet. UiT Norges arktiske universitet
Forskningsrapport
Berge, Jørgen; Cottier, Finlo; Varpe, Øystein; Renaud, Paul; Falk-Petersen, Stig; Kwasniewski, Sawomir; Griffiths, Colin; Søreide, Janne; Johnsen, Geir; Aubert, Anais; Bjærke, Oda; Hovinen, Johanna Emilia Heidi; Jung-Madsen, Signe; Tveit, Martha; Majaneva, Sanna. (2014) Arctic complexity: A case study on diel vertical migration of zooplankton. Journal of Plankton Research
Vitenskapelig artikkel
Johnsen, Geir; Candeloro, Mauro; Berge, Jørgen; Moline, Mark A.. (2014) Glowing in the dark: Discriminating patterns of bioluminescence from different taxa during the Arctic polar night. Polar Biology
Vitenskapelig artikkel
Johnsen, Geir; Candeloro, Mauro; Berge, Jørgen; Moline, Mark A.. (2014) Erratum to: Glowing in the dark: discriminating patterns of bioluminescence from different taxa during the Arctic polar night. Polar Biology
Korrigendum
Valle, Kristin Collier; Nymark, Marianne; Aamot, Inga; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Brembu, Tore; Bones, Atle M.. (2014) System responses to equal doses of photosynthetically usable radiation of blue, green, and red light in the marine diatom Phaeodactylum tricornutum. PLOS ONE
Vitenskapelig artikkel

2013

Hovland, Erlend Kjeldsberg; Dierssen, Heidi; Ferreira, Ana Sofia; Johnsen, Geir. (2013) Dynamics regulating major trends in Barents Sea temperatures and subsequent effect on remotely sensed particulate inorganic carbon. Marine Ecology Progress Series
Vitenskapelig artikkel
Pettersen, Ragnhild; Johnsen, Geir; Bruheim, Per; Andreassen, Trygve. (2013) Development of hyperspectral imaging as a bio-optical taxonomic tool for pigmented marine organisms. Organisms Diversity & Evolution
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Falk-Pettersen, Stig. (2013) Mørkets hemmeligheter. Svalbardposten
Populærvitenskapelig artikkel
Johnsen, Geir; Volent, Zsolt; Dierssen, Heidi; Pettersen, Ragnhild; Ardelan, Murat Van; Søreide, Fredrik; Fearns, Peter; Ludvigsen, Martin; Moline, Mark A.. (2013) Underwater hyperspectral imagery to create biogeochemical maps of seafloor properties.
Vitenskapelig kapittel
Ludvigsen, Martin; Johnsen, Geir; Lågstad, Petter Arthur; Sørensen, Asgeir Johan; Ødegård, Øyvind. (2013) Scientific operations combining ROV and AUV in the Trondheim Fjord.
Vitenskapelig kapittel
Båtnes, Anna Solvang; Miljeteig, Cecilie; Berge, Jørgen; Greenacre, Michael; Johnsen, Geir. (2013) Quantifying the light sensitivity of Calanus spp. during the polar night: potential for orchestrated migrations conducted by ambient light from the sun, moon, or aurora borealis. Polar Biology
Vitenskapelig artikkel
Nymark, Marianne; Valle, Kristin Collier; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Bones, Atle M.; Brembu, Tore. (2013) Molecular and photosynthetic responses to prolonged darkness and subsequent acclimation to re-illumination in the diatom Phaeodactylum tricornutum. PLOS ONE
Vitenskapelig artikkel

2012

Gabrielsen, Tove M; von Quillfeldt, Cecilie; Johnsen, Geir; Berge, Jørgen. (2012) Varm vinter, sen vår i fjorden. Svalbardposten
Kommentar
Elde, Anette; Pettersen, Ragnhild; Bruheim, Per; Järnegren, Johanna; Johnsen, Geir. (2012) Pigmentation and Spectral Absorbance Signatures in Deep-Water Corals from the Trondheimsfjord, Norway. Marine Drugs
Vitenskapelig artikkel
Hovland, Erlend Kjeldsberg; Hancke, Kasper; Alver, Morten; Drinkwater, Kennneth F.; Høkedal, Jo; Johnsen, Geir; Moline, Mark A.; Sakshaug, Egil. (2012) Optical impact of an Emiliania huxleyi bloom in the frontal region of the Barents Sea. Journal of Marine Systems
Vitenskapelig artikkel
Hancke, Kasper; Hovland, Erlend Kjeldsberg; Volent, Zsolt; Pettersen, Ragnhild; Johnsen, Geir; Moline, Mark A.; Sakshaug, Egil. (2012) Optical properties of CDOM across the Polar Front in the Barents Sea: Origin, distribution and significance. Journal of Marine Systems
Vitenskapelig artikkel
Berge, Jørgen; Båtnes, Anna Solvang; Johnsen, Geir; Blackwell, Susan; Moline, Mark A.. (2012) Bioluminescence in the high Arctic during the polar night. Marine Biology
Vitenskapelig artikkel

2011

Volent, Zsolt; Johnsen, Geir; Hovland, Erlend Kjeldsberg; Folkestad, Are; Olsen, Lasse Mork; Tangen, Karl; Sørensen, Kai. (2011) Improved monitoring of phytoplankton bloom dynamics in a Norwegian fjord by integrating satellite data, pigment analysis, and Ferrybox data with a coastal observation network. Journal of Applied Remote Sensing
Vitenskapelig artikkel
Johnsen, Geir; Moline, Mark; Pettersson, Lasse H.; Pinckney, J. L.; Pozdnyakov, Dmitry; Egeland, Einar Skarstad; Schofield, O. M.. (2011) Optical monitoring of phytoplankton bloom pigment signatures.
Vitenskapelig kapittel
Thoen, Hanne Halkinrud; Johnsen, Geir; Berge, Jørgen. (2011) Pigmentation and spectral absorbance in the deep-sea arctic amphipods Eurythenes gryllus and Anonyx sp. Polar Biology
Vitenskapelig artikkel
Pettersen, Ragnhild; Johnsen, Geir; Berge, Jørgen; Hovland, Erlend Kjeldsberg. (2011) Phytoplankton chemotaxonomy in waters around the Svalbard archipelago reveals high amounts of Chl b and presence of gyroxanthin-diester. Polar Biology
Vitenskapelig artikkel
Jouenne, Fabien; Eikrem, Wenche; Gall, F Le; Marie, Dominique; Johnsen, Geir; Vaulot, Daniel. (2011) Prasinoderma singularis sp. nov. (Prasinophyceae, Chlorophyta), a Solitary Coccoid Prasinophyte from the South-East Pacific Ocean. Protist
Vitenskapelig artikkel
Roy, Suzanne; Llewellyn, Carole; Egeland, Einar Skarstad; Johnsen, Geir. (2011) Preface.
Innledning i antologi
Llewellyn, Carole A.; Roy, Suzanne; Johnsen, Geir; Egeland, Einar Skarstad; Chauton, Matilde; Hallegraeff, Gustaff; Lohr, Martin; Oster, Ulrike; Porra, Robert J.; Scheer, Hugo; Zhao, Kai-Hong. (2011) Perspectives on future directions.
Vitenskapelig kapittel
Brunet, Christophe; Johnsen, Geir; Lavaud, Johan; Roy, Suzanne. (2011) Pigments and photoacclimation processes.
Vitenskapelig kapittel
Johnsen, Geir; Bricaud, Annick; Nelson, Norman; Prézelin, Barbara; Bidigare, Robert. (2011) In vivo bio-optical properties of phytoplankton pigments.
Vitenskapelig kapittel

2010

Aamot, Inga; Berge, Jørgen; Hancke, Kasper; Johnsen, Geir; Moline, Mark; Schofield, Oscar. (2010) NORUS - Technology Development for Marine Monitoring and Ocean Observation:An North America-Norway educational program. http://ipy-osc.no/abstract/
Konferanseabstract
Thoen, Hanne Halkinrud; Johnsen, Geir; Berge, Jørgen. (2010) Pigmentation and spectral absorbance in the deep-sea arctic amphipods Eurythenes gryllus and Anonyx sp. Polar Biology
Vitenskapelig artikkel
Johnsen, Geir; Søreide, Fredrik. (2010) Underwater hyperspectral imaging of marine mineral deposits. Underwater Mining meeting Institute (UMI)
Konferanseabstract

2009

Johnsen, Geir; Nepstad, Ina. (2009) Cloning and characterisation of interleukin-6 and interleukin-11b in Atlantic halibut (Hippoglossus hippoglossus). NTNU, Institutt for biologi
Masteroppgave
Sakshaug, E.; Johnsen, Geir; Kristiansen, Svein; Quillfeldt, C.v.; Rey, F.; Slagstad, D.; Thingstad, F.. (2009) Phytoplankton and primary production.
Vitenskapelig kapittel
Johnsen, Geir; Volent, Z; Sakshaug, E.; Sigernes, Fred; Pettersson, L.H.. (2009) Remote sensing in the Barents Sea.
Vitenskapelig kapittel
Evertsen, Jussi; Johnsen, Geir. (2009) In vivo and in vitro differences in chloroplast functionality in the two north Atlantic sacoglossans (Gastropoda, Opisthobranchia) Placida dendritica and Elysia viridis. Marine Biology
Vitenskapelig artikkel
Sakshaug, E.; Johnsen, Geir; Volent, Z. (2009) Light.
Vitenskapelig kapittel
Berge, Jørgen; Lønne, Ole Jørgen; Renaud, Paul; Johnsen, Geir; Gulliksen, Bjørn; Varpe, Øystein; Nygård, Henrik. (2009) Polartorsken - vil den bli utkonkurrert av sørlige fiskearter?. Svalbardposten
Populærvitenskapelig artikkel
Berge, Jørgen; Cottier, Finlo; Last, Kim S.; Varpe, Øystein; Leu, Eva; Søreide, Janne; Eiane, Ketil; Falk-Petersen, S.; Willis, Kate; Nygård, Henrik; Vogedes, Daniel; Griffiths, Collin; Johnsen, Geir; Lorentzen, Dag Arne; Brierley, A.S.. (2009) Diel vertical migration of Arctic zooplankton during the polar night. Biology Letters
Vitenskapelig artikkel
Quillfeldt, Cecilie H. von; Hegseth, Else Nøst; Johnsen, Geir; Sakshaug, Egil; Syvertsen, Erik. (2009) Ice algae.
Vitenskapelig kapittel
Nymark, Marianne; Valle, Kristin Collier; Brembu, Tore; Winge, Per; Hancke, Kasper; Andresen, Kjersti; Johnsen, Geir; Bones, Atle M.. (2009) An integrated analysis of molecular acclimation to high light in the marine diatom Phaeodactylum tricornutum. PLOS ONE
Vitenskapelig artikkel
Quillfeldt, C.v.; Hegseth, E.N.; Johnsen, Geir; Sakshaug, E.; Syvertsen, E.E.. (2009) Ice algae.
Vitenskapelig kapittel
Sakshaug, Egil; Johnsen, Geir; Kristiansen, Svein; von Quillfeldt, Cecilie; Rey, Francisco; Slagstad, Dag; Thingstad, Frede. (2009) Phytoplankton and primary production.
Vitenskapelig kapittel
Johnsen, Geir; Volent, Zsolt; Sakshaug, Egil; Sigernes, Fred; Pettersson, Lasse H.. (2009) Remote sensing in the Barents Sea.
Vitenskapelig kapittel
Volent, Z; Johnsen, Geir; Sigernes, Fred. (2009) Microscopic hyperspectral imaging used as a bio-optical taxonomic tool for micro- and macroalgae. Applied Optics
Vitenskapelig artikkel
Sakshaug, Egil; Johnsen, Geir; Volent, Z.. (2009) Light.
Vitenskapelig kapittel
von Quillfeldt, Cecilie; Hegseth, Else Nøst; Johnsen, Geir; Sakshaug, Egil; Syvertsen, Erik E.. (2009) Ice algae.
Vitenskapelig kapittel

2008

Hancke, Torunn Beate; Hancke, Kasper; Johnsen, Geir; Sakshaug, Egil. (2008) Rate of O2 production derived from pulse-amplitude-modulated fluorescence: Testing three biooptical approaches against measured O2-production rate. Journal of Phycology
Vitenskapelig artikkel
Hovland, Erlend Kjeldsberg; Johnsen, Geir; Moline, Mark. (2008) Combined use of AUV and hyperspectral imaging to mapping sea-surface and macroalgae. Ocean Optics
Konferanseabstract
Bredholt, Harald; Fjærvik, Espen; Johnsen, Geir; Zotchev, Sergey. (2008) Actinomycetes from sediments in the Trondheim Fjord, Norway: Diversity and biological activity. Marine Drugs
Vitenskapelig artikkel
Hancke, Kasper; Hancke, Torunn Beate; Olsen, Lasse Mork; Johnsen, Geir; Glud, RN. (2008) Temperature effects on microalgal photosynthesis-light responses measured by O2 production, pulse-amplitude-modulated fluorescence, and C-14 assimilation. Journal of Phycology
Vitenskapelig artikkel
Bakken, Torkild; Evertsen, Jussi; Johnsen, Geir. (2008) Vitenskapelig dykking - behov for endringer i forskriften. Dykkenytt : informasjonsorgan for dykkeindustrien
Fagartikkel

2007

Cibic, Tamara; Blasutto, Oriana; Hancke, Kasper; Johnsen, Geir. (2007) Microphytobenthic species composition, pigment concentration, and primary production in sublittoral sediments of the Trondheimsfjord (Norway). Journal of Phycology
Vitenskapelig artikkel
Edvardsen, B; Eikrem, W; Shalchian-Tabrizi, K; Riisberg, I; Johnsen, Geir; Naustvoll, L; Throndsen, J. (2007) Verrucophora farcimen gen. et sp nov (Dictyochophyceae, Heterokonta) - A bloom-forming ichthyotoxic flagellate from the Skagerrak, Norway. Journal of Phycology
Vitenskapelig artikkel
Hancke, Kasper; Johnsen, Geir; Sakshaug, Egil. (2007) Bio-optical properties and spectral attenuation of photosynthetically available radiation: relation to primary productivity and phytoplankton composition. In Proceedings from Arctic Frontiers: balancing human use and ecosystem protection. UiT Norges arktiske universitet
Forskningsrapport
Johnsen, Geir; Volent, Zsolt; Sigernes, F.; Berge, Jørgen; Hovland, Erlend Kjeldsberg; Sakshaug, Egil. (2007) Local hyperspectral imaging of ocean colour from tethered balloons in the Arctic. In Proceedings from Arctic Frontiers: Balancing human use and ecosystem protection. UiT Norges arktiske universitet
Forskningsrapport
Berge, Jørgen; Schander, C; Pampanin, D.M.; Johnsen, Geir. (2007) The past, present and future of the Mytilus edulis population on Svalbard. In Proceedings from Arctic Frontiers: Balancing human use and ecosystem protection. UiT Norges arktiske universitet
Forskningsrapport
Johnsen, Geir; Volent, Zsolt; Sigernes, F.. (2007) Fine scale studies using hyper-spectral remote sensing. ESSAS Meeting in Marine Arctic Climate
Forskningsrapport
Johnsen, Geir; Sakshaug, Egil. (2007) Biooptical characteristics of PSII and PSI in 33 species (13 pigment groups) of marine phytoplankton, and the relevance for pulse-amplitude-modulated and fast-repetition-rate fluorometry. Journal of Phycology
Vitenskapelig artikkel
Johnsen, Geir. (2007) Arctic Life: Bridging ecosystem function using remote sensing technologies. Svalbard Science Forum
Populærvitenskapelig artikkel
Carlsen, BP; Johnsen, Geir; Berge, Jørgen; Kuklinski, P. (2007) Biodiversity patterns of macro-epifauna on different lamina parts of Laminaria digitata and Saccharina latissima collected during spring and summer 2004 in Kongsfjorden, Svalbard. Polar Biology
Vitenskapelig artikkel
Volent, Z; Johnsen, Geir; Sigernes, Fred. (2007) Kelp forest mapping by use of airborne hyperspectral imager. Journal of Applied Remote Sensing
Vitenskapelig artikkel
Evertsen, Jussi; Burghardt, Ingo; Johnsen, Geir; Wägele, Heike. (2007) Retention of functional chloroplasts in some sacoglossans from the Indo-Pacific and Mediterranean. Marine Biology
Vitenskapelig artikkel
Ludvigsen, Martin; Sortland, Bjørn; Johnsen, Geir; Singh, Hanumant. (2007) Applications of Geo-Referenced Underwater Photo Mosaics in Marine Biology and Archaeology. Oceanography
Vitenskapelig artikkel

2006

Olsen, Lasse Mork; Öztürk, M.; Sakshaug, Egil; Johnsen, Geir. (2006) Photosynthesis-induced phosphate precipitation in seawater: ecological implications for phytoplankton. Marine Ecology Progress Series
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Nilsen, Frank; Gulliksen, Bjørn; Slagstad, Dag; Pampanin, Daniella. (2006) The Mytilus edulis population in Svalbard: how and why. Marine Ecology Progress Series
Vitenskapelig artikkel
Rodriguez, F; Chauton, Matilde Skogen; Johnsen, Geir; Andresen, Kjersti; Olsen, Lasse Mork; Zapata, M.. (2006) Photoacclimation in phytoplankton: implications for biomass estimates, pigment functionality and chemotaxonomy. Marine Biology
Vitenskapelig artikkel
Johnsen, Geir. (2006) Warming Arctic sees return of blue mussels after 1000 years. National Geographic
Populærvitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Nilsen, Frank; Nilsen, Frank; Gulliksen, Bjørn; Slagstad, Dag; Pampanin, Daniela M.. (2006) The Mytilus edulis population in Svalbard: how and why. Marine Ecology Progress Series
Leder
Onstad, L; Evertsen, Jussi; Johnsen, Geir. (2006) Snegle på solceller. Gemini
Populærvitenskapelig artikkel
Roy, Suzanne; Egeland, Einar Skarstad; Johnsen, Geir; Llewellyn, Carole; Wright, Simon. (2006) Report of a Workshop on a Follow-Up Volume of the Book "Phytoplankton Pigments in Oceanography". Scientific Committee on Oceanic Research
Forskningsrapport

2005

Burghardt, Ingo; Evertsen, Jussi; Johnsen, Geir; Wägele, Heike. (2005) Solar powered seaslugs - Mutualistic symbiosis of aeolid nudibranchia (Mollusca, Gastropoda, Opisthobranchia) with Symbiodinium. Symbiosis
Vitenskapelig artikkel
Fossmark, Reidar; Johnsen, Geir; Waldum, Helge; Johannesen, Eli Marie. (2005) Rebound acid hypersecretion after long-term inhibition of gastric acid secretion. Alimentary Pharmacology and Therapeutics
Vitenskapelig artikkel
Sakshaug, Egil; Johnsen, Geir. (2005) Algal cultures, Analogues of Blooms and Applications. Multi-Science Publishing
Antologi
Berge, J; Johnsen, Geir; Nilsen, F; Gulliksen, B; Slagstad, D. (2005) Ocean temperature oscillations causes the reappearance of blue mussels in Svalbard after 1000 years of absence. Marine Ecology Progress Series
Vitenskapelig artikkel
Sakshaug, Egil; Johnsen, Geir. (2005) Absorption, fluorescence excitation and photoacclimation in phytoplankton.
Vitenskapelig kapittel
Bordvik, Hans Otto; Johnsen, Geir. (2005) “En glupsk nellik”. NEWTON websider (NRK)
Populærvitenskapelig artikkel
Indergaard, M; Nordtvedt, M; Johnsen, Geir. (2005) Satellittmålinger for miljøet (SISCAL project, NTNU, IBI). Gemini
Populærvitenskapelig artikkel
Bordvik, Hans Otto; Johnsen, Geir. (2005) “Forskning og foto under vann”. NEWTON websider (NRK)
Populærvitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Nilsen, Frank; Gulliksen, Bjørn; Slagstad, Dag. (2005) Ocean temperature oscillations enable reappearance of blue mussels Mytilus edulis in Svalbard after 1000 year absence. Marine Ecology Progress Series
Vitenskapelig artikkel

2004

Chauton, Matilde Skogen; Tilstone, Gavin; Legrand, Catherine; Johnsen, Geir. (2004) Changes in pigmentation, bio-optical characteristics and photophysiology, during phytoflagellate succession in mesocosms. Journal of Plankton Research
Vitenskapelig artikkel
Hancke, Torunn Beate; Johnsen, Geir. (2004) SISCAL processor evaluation document. www.siscal.net
Forskningsrapport

2003

Johansen, Torunn Beate; Johnsen, Geir. (2003) SISCAL prototype evaluation document. www.siscal.net. Satellite-based Information System on Coastal Areas and Lakes. IST 2000
Vitenskapelig artikkel
Chauton, Matilde Skogen; Optun, Odd Inge; Bathen, F. T; Volent, Z.; Gribbestad, Ingrid S.; Johnsen, Geir. (2003) HR MAS 1H NMR spectroscopy analysis of whole cells of marine microalgae. Marine Ecology Progress Series
Vitenskapelig artikkel
Figueroa, F. L.; Escassi, L.; Perez-Rodriguez, E.; Korbee, N.; Johnsen, Geir. (2003) Effects of the irradiance in the short-term on accumulation of mycosporine like amino acids in sun and shade species of the red algal genus Porphyra. Photochemistry and Photobiology
Vitenskapelig artikkel
Johansen, Torunn Beate; Johnsen, Geir. (2003) SISCAL End User Requirement evaluation document. www.siscal.net. Satellite-based Information System on Coastal Areas and Lakes. IST 2000
Vitenskapelig artikkel

2002

Johnsen, Geir; Børsheim, Knut Yngve; Johansen, Torunn Beate. (2002) Production and mortality of phytoplankton and sea-ice microalgae in the southern ocean. Rapportserie (Norsk polarinstitutt)
Vitenskapelig artikkel
Millie, David; Schofield, Oscar; Kirkpatrick, Gary J.; Johnsen, Geir; Evens, Tim J.. (2002) Using absorbance and fluorescence spectra to discriminate microalgae. European journal of phycology
Vitenskapelig artikkel
Gileptis, Laura; Johnsen, Geir; Moxness, Helge; Norwich, Inger; Vangen, Steffen. (2002) Modul for mønstergjenkjenning/klassifisering i DynamicImager ved bruk av backpropagation-algoritmen. Piksel'n : Organ for NOBIM (Norsk forening for bildebehandling og mønstergjenkjenning)
Vitenskapelig artikkel
Johansen, Torunn Beate; Johnsen, Geir. (2002) End User requirement evaluation document. [Mangler utgivernavn]
Forskningsrapport
Johansen, Torunn Beate; Johnsen, Geir. (2002) End User Requirements document. [Mangler utgivernavn]
Forskningsrapport

1995

Jovine, R. V.; Johnsen, Geir; Prezelin, B. B.. (1995) Isolation of membrane bound chlorophyll a-chlorofhyll c binding light harvesting complexes from the dinoflagellates heterocapsa pygmaea and Prorocentrum minimum. Photosynthesis Research
Vitenskapelig artikkel
Egeland, E.; Johnsen, Geir; Eikrem, W.; Jensen, S. Liaaen-; Throndsen, J.. (1995) The pigments of Bathycoccus prasinos. Journal of Phycology
Vitenskapelig artikkel
Johnsen, Geir; Sakshaug, Egil. (1995) Light harvesting in bloom-forming marine phytoplankton: species-specificity and photoadaption. Scientia Marina
Vitenskapelig artikkel

1994

Johnsen, Geir. (1994) Light Harvesting and Utiliation in Marine Phytoplankton: Species-Specific and Photoadaptive Responses. Dr. Scient. Thesis in Marine Botany, University of Trondheim
Doktoravhandling
Jovine, R. V.; Schofield, O.; Johnsen, Geir; Prezelin, B. B.. (1994) Photoacclimatory differences in the light-harvesting complex of the bloom forming dinoflagellates Heterocapsa pygmaea and Prorocentrum minimum. Journal of Phycology
Vitenskapelig artikkel
Johnsen, Geir; Samset, O.; Granskog, L.; Sakshaug, Egil. (1994) In vivo absorption characteristics in 10 classes of phytoplankton: Taxonomic characteristics and responses to photoadaption by means of discriminant and HPLC analysis. Marine Ecology Progress Series
Vitenskapelig artikkel
Johnsen, Geir; Nelson, N. B.; Jovine, R. V. M.; Prezelin, B. B.. (1994) Chromoprotein- and pigment-dependent modeling of spectral light absorption in two dinoflagellates, Prorocentrum minimum and Heterocapsa pygmaea. Marine Ecology Progress Series
Vitenskapelig artikkel
Jovine, R. V; Johnsen, Geir; Prezelin, B. B. (1994) Photoadaptation of Prorocentrum minimum and Heterocapsa pygmaea (Dinoflagellates): Chromoprotein changes and the consequenses for spectral absorption. EOS
Vitenskapelig artikkel

1993

Gilstad, Mona; Johnsen, Geir; Sakshaug, Egil. (1993) Photosynthetic parameters, pigment composition and respiration rates of the marine diatom Skeletonema costatum grown in continuous light and a 12:1 light-dark cycle. Journal of Plankton Research
Vitenskapelig artikkel
Johnsen, Geir; Sakshaug, Egil. (1993) Bio-optical characteristics and photoadaptive responses in the toxic and bloomforming dinoflagellates Gyrodinium aureolum, Gymnodinium galatheanum two strains of Prorocentrum minium. Journal of Phycology
Vitenskapelig artikkel
Volent, Zsolt; Johnsen, Geir. (1993) Presentation of an optical sensor-"OPTISENS" designed for Eulerian measurements of Phytoplankton on a buoy. Underwater light measurements. Proceedings from International Symposium on high latitude optics.
Vitenskapelig artikkel

1992

Syvertsen, E.; Hegseth, E; Johnsen, Geir; Sakshaug, Egil; Gulliksen, B; Lønne, O. J; Aarseth, A. (1992) Livet i isen (The life in the ice). In Økosystem Barentshavet. [Mangler utgivernavn]
Faglig monografi
Sakshaug, Egil; Kristiansen, S; Syvertsen, E; Eilertsen, H. C; Gilstad, M; Hegseth, E. N; Hewes, C; Holm-Hansen, O; Johnsen, Geir; Mitchell, B. G; Rey, F; Slagstad, D. (1992) Planktonalger (Phytoplankton). In Økosystem Barentshavet. [Mangler utgivernavn]
Faglig monografi
Johnsen, Geir; Sakshaug, Egil; Vernet, Maria. (1992) Pigment composition, spectral characteriation and photosynthetic parameters in Chrysochromulina polylepis. Marine Ecology Progress Series
Vitenskapelig artikkel
Volent, Zsolt; Johnsen, Geir. (1992) Presentation of an optical sensor-"OPTISENS" designed for Eulerian measurements of Phytoplankton on a moored buoy. ABOOS (Autonomous Bio-Optical Observing Systems) Scientific Symposium : Abstracts
Vitenskapelig artikkel
Johnsen, Geir; Samset, Oddgeir; Zsolt, Volent. (1992) Bio-optical characteristicts of phytoplankton in relation to remote sensing. ABOOS (Autonomous Bio-Optical Observing Systems) Scientific Symposium : Abstracts
Vitenskapelig artikkel

1991

Sakshaug, Egil; Johnsen, Geir; Andresen, Kjersti; Vernet, Maria. (1991) Modeling of light-dependent algal photosynthesis and growth: Experiments with the Barents Sea diatoms Thalassiosira nordensskioeldii and Chaetocero furcellatus. Deep-Sea Research Part II: Topical Studies in Oceanography
Vitenskapelig artikkel
Johnsen, Geir; Hegseth, Else Nøst. (1991) Photoadaptation of sea-ice microalgae in the Barents Sea. Polar Biology
Vitenskapelig artikkel
Johnsen, Geir. (1991) Identification of Chrysochromulina leadbeateri by means of remote sensing. Fisken og Havet
Vitenskapelig artikkel
Sakshaug, Egil; Johnsen, Geir; Samset, Oddgeir; Zsolt, Volent. (1991) Identification of phytoplankton blooms by means of remote sensing. Environment Northern Seas
Vitenskapelig artikkel
Johnsen, Geir. (1991) Proceedings from a scientific working meeting. Fisken og Havet
Vitenskapelig artikkel

Tidsskriftspublikasjoner

Paiba Garcia, Laura Catherine; Perrin, Sam Wenaas; Johnsen, Geir; Finstad, Anders Gravbrøt; Bakken, Torkild. (2026) Application of an integrated Species Distribution Model (iSDM) for deep-sea marine habitats: Knowledge gaps in the Norwegian extended continental shelf. Ecological Informatics
Vitenskapelig artikkel
Osanen, Janina Emilia; Lange, Benjamin Allen; Campbell, Karley; Johnsen, Geir; Günzel, Leonard Florian Tom; Moreira Fragoso, Glaucia. (2026) Two-platform approach to mapping Arctic sea ice algal aggregates using underwater hyperspectral imaging. Elementa: Science of the Anthropocene
Vitenskapelig artikkel
Nevstad, Malin Bø; Bakken, Torkild; Løvås, Håvard Snefjellå; Hancke, Kasper; Johansen, Tor Arne; Johnsen, Geir. (2026) Hyperspectral Imaging of Seagrass and Macroalgae Using Uncrewed Aerial and Surface Vehicles for Coastal Habitat Mapping. Remote Sensing
Vitenskapelig artikkel
Summers, Natalie Maria; Bremnes, Jens Einar; Liu, Hongbo; Løvås, Håvard Snefjellå; Moreira Fragoso, Glaucia; Johnsen, Geir. (2026) Assessing Arctic under sea-ice light regimes and ice algal bio-optical properties using ROV-based hyperspectral imaging. Polar Biology
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Hama, Nalia; Snijder, Elisabeth; Aldridge, David; Borrero Santiago, Ana Rocio; Broch, Ole Jacob; Johnsen, Geir; Olsen, Yngvar; Hatlebakk, Maja Karoline Viddal. (2026) The influence of environmental factors and phytoplankton blooms on cyphonautes larvae abundance and bryozoan colony development at a kelp farm in central Norway. Marine Environmental Research
Vitenskapelig artikkel
Paiba Garcia, Laura Catherine; Johnsen, Geir; Perrin, Sam Wenaas; Bakken, Torkild. (2025) Open‐Source Marine Biodiversity Data Quality in the Norwegian Sea Spanning 149 Years: Knowledge Gaps in the Deep‐Sea Mining Opening Area. Ecology and Evolution
Vitenskapelig artikkel
Johnsen, Geir; Børsheim, Knut Yngve; Johansen, Torunn Beate. (2002) Production and mortality of phytoplankton and sea-ice microalgae in the southern ocean. Rapportserie (Norsk polarinstitutt)
Vitenskapelig artikkel
Kauko, Hanna Maria; Pavlov, Alexey; Johnsen, Geir; Granskog, Mats; Peeken, Ilka; Assmy, Philipp. (2019) Photoacclimation state of an Arctic underice phytoplankton bloom. Journal of Geophysical Research (JGR): Oceans
Vitenskapelig artikkel
Kauko, Hanna Maria; Taskjelle, Torbjørn; Assmy, Philipp; Pavlov, Alexey K.; Mundy, C.J.; Duarte, Pedro; Fernández-Méndez, Mar; Olsen, Lasse Mork; Hudson, Stephen R.; Johnsen, Geir; Elliott, Ashley; Wang, Feiyue; Granskog, Mats A.. (2017) Windows in Arctic sea ice: light transmission and ice algae in a refrozen lead. Journal of Geophysical Research (JGR): Biogeosciences
Vitenskapelig artikkel
Schartmüller, Bernhard; Mckee, David; Berge, Jørgen; Johnsen, Geir. (2024) Calibration verification of an underwater hyperspectral imaging push broom instrument to measure light in absolute units and field demonstration. Applied Optics
Vitenskapelig artikkel
Ringvold, Halldis; Taite, Morag; Allcock, A. Louise; Vecchione, Michael; Péan, Michel; Sandulli, Roberto; Johnsen, Geir; Fjellheim, Arne; Bakke, Snorre; Sannæs, Hanne; Synnes, Ann-Elin; Coronel, José; Hansen, Martin; Olejar, Peter; Eliassen, Geir; Eliassen, Anita; Klungland, Karl. (2021) In situ recordings of large gelatinous spheres from NE Atlantic, and the first genetic confirmation of egg mass of Illex coindetii (Vérany, 1839) (Cephalopoda, Mollusca). Scientific Reports
Vitenskapelig artikkel
Hancke, Torunn Beate; Hancke, Kasper; Johnsen, Geir; Sakshaug, Egil. (2008) Rate of O2 production derived from pulse-amplitude-modulated fluorescence: Testing three biooptical approaches against measured O2-production rate. Journal of Phycology
Vitenskapelig artikkel
Cibic, Tamara; Blasutto, Oriana; Hancke, Kasper; Johnsen, Geir. (2007) Microphytobenthic species composition, pigment concentration, and primary production in sublittoral sediments of the Trondheimsfjord (Norway). Journal of Phycology
Vitenskapelig artikkel
Olsen, Lasse Mork; Öztürk, M.; Sakshaug, Egil; Johnsen, Geir. (2006) Photosynthesis-induced phosphate precipitation in seawater: ecological implications for phytoplankton. Marine Ecology Progress Series
Vitenskapelig artikkel
Bazilchuk, Nancy Reney; Fossum, Trygve Olav; Moreira Fragoso, Glaucia; Ludvigsen, Martin; Johnsen, Geir. (2019) Smart undervannsrobot leter etter plankton. Av N Bazilchuk. Forskning.no. Angående NTNU Entice prosjekt publisert i Science Robotics. Forskning.no
Populærvitenskapelig artikkel
Burghardt, Ingo; Evertsen, Jussi; Johnsen, Geir; Wägele, Heike. (2005) Solar powered seaslugs - Mutualistic symbiosis of aeolid nudibranchia (Mollusca, Gastropoda, Opisthobranchia) with Symbiodinium. Symbiosis
Vitenskapelig artikkel
Bazilchuk, Nancy Reney; Berge, Jørgen; Johnsen, Geir. (2021) Lysforurensning I Arktis kan ha ødelagt forskningsresultater. Gemini.no
Populærvitenskapelig artikkel
Cardwell, CR; Berge, Jørgen; Johnsen, Geir. (2021) Arctic voyage shines light on some cold, hard truths. The Herald, UK
Populærvitenskapelig artikkel
Bazilchuk, Nancy Reney; Stahl, Annette; Johnsen, Geir; Saad, Aya; Thu, Maren; Nøland, Annecken; Aberle-Malzahn, Nicole. (2021) Sporhunden som lukter mikroalger. Gemini.no
Populærvitenskapelig artikkel
Johansen, Torunn Beate; Johnsen, Geir. (2003) SISCAL prototype evaluation document. www.siscal.net. Satellite-based Information System on Coastal Areas and Lakes. IST 2000
Vitenskapelig artikkel
Hovland, Erlend Kjeldsberg; Dierssen, Heidi; Ferreira, Ana Sofia; Johnsen, Geir. (2013) Dynamics regulating major trends in Barents Sea temperatures and subsequent effect on remotely sensed particulate inorganic carbon. Marine Ecology Progress Series
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Nilsen, Frank; Gulliksen, Bjørn; Slagstad, Dag; Pampanin, Daniella. (2006) The Mytilus edulis population in Svalbard: how and why. Marine Ecology Progress Series
Vitenskapelig artikkel
Evertsen, Jussi; Johnsen, Geir. (2009) In vivo and in vitro differences in chloroplast functionality in the two north Atlantic sacoglossans (Gastropoda, Opisthobranchia) Placida dendritica and Elysia viridis. Marine Biology
Vitenskapelig artikkel
Volent, Zsolt; Johnsen, Geir; Hovland, Erlend Kjeldsberg; Folkestad, Are; Olsen, Lasse Mork; Tangen, Karl; Sørensen, Kai. (2011) Improved monitoring of phytoplankton bloom dynamics in a Norwegian fjord by integrating satellite data, pigment analysis, and Ferrybox data with a coastal observation network. Journal of Applied Remote Sensing
Vitenskapelig artikkel
Donahue, Michelle; Berge, Jørgen; Johnsen, Geir; Ødegård, Øyvind. (2016) The age of humans - living in the anthropocene - "Termites of the sea" found munching wood near Arctic shipwrecks. Smithsonian
Populærvitenskapelig artikkel
Summers, Natalie; Johnsen, Geir; Mogstad, Aksel Alstad; Løvås, Håvard; Moreira Fragoso, Glaucia; Berge, Jørgen. (2022) Underwater Hyperspectral Imaging of Arctic Macroalgal Habitats during the Polar Night Using a Novel Mini-ROV-UHI Portable System. Remote Sensing
Vitenskapelig artikkel
Førde, Henny; Forbord, Silje; Handå, Aleksander; Fossberg, Julia; Arff, Johanne; Johnsen, Geir; Reitan, Kjell Inge. (2016) Development of bryozoan fouling on cultivated kelp (Saccharina latissima) in Norway. Journal of Applied Phycology
Vitenskapelig artikkel
Hovland, Erlend Kjeldsberg; Johnsen, Geir; Moline, Mark. (2008) Combined use of AUV and hyperspectral imaging to mapping sea-surface and macroalgae. Ocean Optics
Konferanseabstract
Ramirez-Llodra, Eva; Hilário, Ana; Paulsen, Emil; Costa, Carolina; Bakken, Torkild; Johnsen, Geir; Rapp, Hans Tore. (2020) Benthic Communities on the Mohn’s Treasure Mound: Implications for Management of Seabed Mining in the Arctic Mid-Ocean Ridge. Frontiers in Marine Science
Vitenskapelig artikkel
Ødegård, Øyvind; Mogstad, Aksel Alstad; Johnsen, Geir; Sørensen, Asgeir Johan; Ludvigsen, Martin. (2018) Underwater hyperspectral imaging: a new tool for marine archaeology. Applied Optics
Vitenskapelig artikkel
Rodriguez, F; Chauton, Matilde Skogen; Johnsen, Geir; Andresen, Kjersti; Olsen, Lasse Mork; Zapata, M.. (2006) Photoacclimation in phytoplankton: implications for biomass estimates, pigment functionality and chemotaxonomy. Marine Biology
Vitenskapelig artikkel
Pettersen, Ragnhild; Johnsen, Geir; Bruheim, Per; Andreassen, Trygve. (2013) Development of hyperspectral imaging as a bio-optical taxonomic tool for pigmented marine organisms. Organisms Diversity & Evolution
Vitenskapelig artikkel
Edvardsen, B; Eikrem, W; Shalchian-Tabrizi, K; Riisberg, I; Johnsen, Geir; Naustvoll, L; Throndsen, J. (2007) Verrucophora farcimen gen. et sp nov (Dictyochophyceae, Heterokonta) - A bloom-forming ichthyotoxic flagellate from the Skagerrak, Norway. Journal of Phycology
Vitenskapelig artikkel
Cohen, Jonathan H.; Berge, Jørgen; Moline, Mark A.; Sørensen, Asgeir Johan; Last, Kim; Falk-Petersen, Stig; Renaud, Paul; Leu, Eva; Grenvald, Julie Cornelius; Cottier, Finlo; Cronin, Heather; Menze, Sebastian; Norgren, Petter; Varpe, Øystein; Daase, Malin; Darnis, Gérald; Johnsen, Geir. (2015) Is ambient light during the high Arctic polar night sufficient to act as a visual cue for zooplankton?. PLOS ONE
Vitenskapelig artikkel
Fossmark, Reidar; Johnsen, Geir; Waldum, Helge; Johannesen, Eli Marie. (2005) Rebound acid hypersecretion after long-term inhibition of gastric acid secretion. Alimentary Pharmacology and Therapeutics
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Davies, Emlyn John; Ellingsen, Ingrid H.; Chauton, Matilde Skogen; Fossum, Trygve Olav; Ludvigsen, Martin; Steinhovden, Kristine; Rajan, Kanna; Johnsen, Geir. (2019) Physical controls on phytoplankton size structure, photophysiology and suspended particles in a Norwegian biological hotspot. Progress in Oceanography
Vitenskapelig artikkel
Dumke, Ines; Purser, Autun; Marcon, Yann; Nornes, Stein Melvær; Johnsen, Geir; Ludvigsen, Martin; Søreide, Fredrik. (2018) Underwater hyperspectral imaging as an in situ taxonomic tool for deep-sea megafauna. Scientific Reports
Vitenskapelig artikkel
Schartmuller, Bernhard; Anderson, Philip; Mckee, David; Connan-McGinty, Stacey; Kopec, Tomasz Piotr; Daase, Malin Hildegard Elisabeth; Johnsen, Geir; Berge, Jørgen. (2023) Development and calibration of a high dynamic range and autonomous ocean-light instrument to measure sub-surface profiles in ice-covered waters. Applied Optics
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Johnsen, Geir; Chauton, Matilde Skogen; Cottier, Finlo Robert; Ellingsen, Ingrid H.. (2020) Phytoplankton community succession and dynamics using optical approaches. Continental Shelf Research
Vitenskapelig artikkel
Williamson, David Roddan; Moreira Fragoso, Glaucia; Majaneva, Sanna Kristiina; Dallolio, Alberto; Halvorsen, Daniel Ørnes; Hasler, Oliver Kevin; Oudijk, Adriënne Esmeralda; Langer, Dennis David; Johansen, Tor Arne; Johnsen, Geir; Stahl, Annette; Ludvigsen, Martin; Garrett, Joseph Landon. (2023) Monitoring Algal Blooms with Complementary Sensors on Multiple Spatial and Temporal Scales. Oceanography
Vitenskapelig artikkel
Berge, Jørgen; Lønne, Ole Jørgen; Renaud, Paul; Johnsen, Geir; Gulliksen, Bjørn; Varpe, Øystein; Nygård, Henrik. (2009) Polartorsken - vil den bli utkonkurrert av sørlige fiskearter?. Svalbardposten
Populærvitenskapelig artikkel
Kauko, Hanna Maria; Olsen, Lasse Mork; Duarte, Pedro; Peeken, Ilka; Granskog, Mats A.; Johnsen, Geir; Fernández-Méndez, Mar; Pavlov, Alexey; Mundy, Christopher John; Assmy, Philipp. (2018) Algal colonization of young arctic sea ice in spring. Frontiers in Marine Science
Vitenskapelig artikkel
Berge, Jørgen; Cottier, Finlo; Last, Kim S.; Varpe, Øystein; Leu, Eva; Søreide, Janne; Eiane, Ketil; Falk-Petersen, S.; Willis, Kate; Nygård, Henrik; Vogedes, Daniel; Griffiths, Collin; Johnsen, Geir; Lorentzen, Dag Arne; Brierley, A.S.. (2009) Diel vertical migration of Arctic zooplankton during the polar night. Biology Letters
Vitenskapelig artikkel
Cohen, Jonathan; Cronin, Heather; Moline, Mark A.; Berge, Jørgen; Johnsen, Geir; Sørensen, Asgeir Johan. (2014) Are krill eyes useful in the high Arctic polar night?. Ocean Optics
Konferanseabstract
Johnsen, Geir; Norli, Marit; Moline, Mark A.; Robbins, Ian; von Quillfeldt, Cecilie; Sørensen, Kai; Cottier, Finlo Robert; Berge, Jørgen. (2018) The advective origin of an under-ice spring bloom in the Arctic Ocean using multiple observational platforms. Polar Biology
Vitenskapelig artikkel
Aamot, Inga; Pokrzywinski, Kaytee; Johnsen, Geir; Berge, Jørgen; Sørensen, Asgeir Johan. (2014) Light Climate and Status of the Photosynthetic Machinery in Macroalgae in the Polar Night. Ocean Optics
Konferanseabstract
Hansen, Ingrid; Pettersen, Ragnhild; Beuchel, Frank; Cochrane, Sabine; Frantzen, marianne; Ekehaug, Stefan; Erdal, Ivar; Johnsen, Geir; Camus, Lionel. (2014) Underwater hyperspectral imaging (UHI) for environmental mapping and monitoring of seabed habitats. Ocean Optics
Konferanseabstract
Berge, J; Johnsen, Geir; Nilsen, F; Gulliksen, B; Slagstad, D. (2005) Ocean temperature oscillations causes the reappearance of blue mussels in Svalbard after 1000 years of absence. Marine Ecology Progress Series
Vitenskapelig artikkel
Berge, Jørgen; Geoffroy, Maxime; Daase, Malin; Cottier, Finlo Robert; Priou, Pierre; Cohen, Jonathan H.; Johnsen, Geir; Mckee, David; Kostakis, Ina; Renaud, Paul Eric; Vogedes, Daniel Ludwig; Anderson, Philip J.; Last, Kim S.; Gauthier, Stephane. (2020) Artificial light during the polar night disrupts Arctic fish and zooplankton behavior down to 200 m depth. Communications Biology
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Falk-Pettersen, Stig. (2013) Mørkets hemmeligheter. Svalbardposten
Populærvitenskapelig artikkel
Nilssen, Ingunn; Ødegård, Øyvind; Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen; Nornes, Stein Melvær; Norgren, Petter; Vieweg, Ireen. (2014) Integrated environmental monitoring; a methodological approach to optimise knowledge gathering and sampling strategy. Ocean Optics
Konferanseabstract
Johnsen, Geir; Ekehaug, Stefan; Hansen, Ingrid; Sørensen, Asgeir Johan. (2014) The use of underwater hyperspectral imaging deployed on remotely operated vehicles to identify, map and monitor bio-geo-chemical objects of interest. Ocean Optics
Konferanseabstract
Nornes, Stein Melvær; Candeloro, Mauro; Ødegård, Øyvind; Johnsen, Geir; Sørensen, Asgeir Johan. (2014) Photomosaic camera as simultaneous data collector and navigation aid on unmanned underwater vehicles. Ocean Optics
Konferanseabstract
Johnsen, Geir. (2006) Warming Arctic sees return of blue mussels after 1000 years. National Geographic
Populærvitenskapelig artikkel
Summers, Natalie Maria; Moreira Fragoso, Glaucia; Johnsen, Geir. (2023) Photophysiologically active green, red, and brown macroalgae living in the Arctic Polar Night. Scientific Reports
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Nilsen, Frank; Nilsen, Frank; Gulliksen, Bjørn; Slagstad, Dag; Pampanin, Daniela M.. (2006) The Mytilus edulis population in Svalbard: how and why. Marine Ecology Progress Series
Leder
Mogstad, Aksel Alstad; Løvås, Håvard; Sture, Øystein; Johnsen, Geir; Ludvigsen, Martin. (2022) Remote Sensing of the Tautra Ridge: An Overview of the World’s Shallowest Cold-Water Coral Reefs. Frontiers in Marine Science
Vitenskapelig artikkel
Johnsen, Geir; Sakshaug, Egil. (2007) Biooptical characteristics of PSII and PSI in 33 species (13 pigment groups) of marine phytoplankton, and the relevance for pulse-amplitude-modulated and fast-repetition-rate fluorometry. Journal of Phycology
Vitenskapelig artikkel
Oudijk, Esmée; Hasler, Oliver Kevin; Øveraas, Henning; Marty, Sabine; Williamson, David Roddan; Svendsen, Torbjørn Karl; Berg, Simen; Birkeland, Roger; Halvorsen, Daniel Ørnes; Bakken, Sivert; Henriksen, Marie Bøe; Alver, Morten; Johnsen, Geir; Johansen, Tor Arne; Stahl, Annette; Kvaløy, Pål; Dallolio, Alberto; Majaneva, Sanna; Moreira Fragoso, Glaucia; Garrett, Joseph. (2022) Campaign For Hyperspectral Data Validation In North Atlantic Coastal Waters. Workshop on Hyperspectral Image and Signal Processing, Evolution in Remote Sensing
Vitenskapelig artikkel
Onstad, L; Evertsen, Jussi; Johnsen, Geir. (2006) Snegle på solceller. Gemini
Populærvitenskapelig artikkel
Dumke, Ines; Nornes, Stein Melvær; Purser, Autun; Marcon, Yann; Ludvigsen, Martin; Ellefmo, Steinar Løve; Johnsen, Geir; Søreide, Fredrik. (2018) First hyperspectral imaging survey of the deep seafloor: High-resolution mapping of manganese nodules. Remote Sensing of Environment
Vitenskapelig artikkel
Faltynkova, Andrea; Johnsen, Geir; Wagner, Martin. (2021) Hyperspectral imaging as an emerging tool to analyze microplastics: A systematic review and recommendations for future development. Microplastics and Nanoplastics
Vitenskapelig oversiktsartikkel
Moreira Fragoso, Glaucia; Davies, Emlyn John; Fossum, Trygve Olav; Ullgren, Jenny; Majaneva, Sanna; Aberle-Malzahn, Nicole; Ludvigsen, Martin; Johnsen, Geir. (2022) Contrasting phytoplankton-zooplankton distributions observed through autonomous platforms, in-situ optical sensors and discrete sampling. PLOS ONE
Vitenskapelig artikkel
Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Lågstad, Petter Arthur; Ødegård, Øyvind. (2014) Scientific Operations Combining ROV and AUV in the Trondheim Fjord. Marine Technology Society journal
Vitenskapelig artikkel
Chauton, Matilde Skogen; Tilstone, Gavin; Legrand, Catherine; Johnsen, Geir. (2004) Changes in pigmentation, bio-optical characteristics and photophysiology, during phytoflagellate succession in mesocosms. Journal of Plankton Research
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Dallolio, Alberto; Grant, Stephen Denis; Garrett, Joseph Landon; Ellingsen, Ingrid Helene; Johnsen, Geir; Johansen, Tor Arne. (2024) The Role of Rapid Changes in Weather on Phytoplankton Spring Bloom Dynamics Captured by an Autonomous Uncrewed Surface Vehicle. Earth and Space Science
Vitenskapelig artikkel
Mogstad, Aksel Alstad; Johnsen, Geir; Ludvigsen, Martin. (2019) Shallow-Water Habitat Mapping using Underwater Hyperspectral Imaging from an Unmanned Surface Vehicle: A Pilot Study. Remote Sensing
Vitenskapelig artikkel
Kleiven, Wanda; Johnsen, Geir; Ardelan, Murat Van. (2019) Sea surface microlayer and elemental composition in phaeo-, chloro-, and rhodophytes in winter and spring. Journal of Phycology
Vitenskapelig artikkel
Mogstad, Aksel Alstad; Ødegård, Øyvind; Nornes, Stein Melvær; Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen. (2020) Mapping the Historical Shipwreck Figaro in the High Arctic Using Underwater Sensor-Carrying Robots. Remote Sensing
Vitenskapelig artikkel
Fossum, Trygve Olav; Eidsvik, Jo; Ellingsen, Ingrid H.; Alver, Morten; Moreira Fragoso, Glaucia; Johnsen, Geir; Mendes, Renato; Ludvigsen, Martin; Rajan, Kanna. (2018) Information-driven robotic sampling in the coastal ocean. Journal of Field Robotics (JFR)
Vitenskapelig artikkel
Fossum, Trygve Olav; Moreira Fragoso, Glaucia; Davies, Emlyn John; Ullgren, Jenny; Mendes, Renato; Johnsen, Geir; Ellingsen, Ingrid H.; Eidsvik, Jo; Ludvigsen, Martin; Rajan, Kanna. (2019) Toward adaptive robotic sampling of phytoplankton in the coastal ocean. Science robotics
Vitenskapelig artikkel
Ingulstad, Mats; Bakken, Torkild; Ellefmo, Steinar Løve; Johnsen, Geir; Hagspiel, Verena. (2024) Villedende om hypotetiske havbunnsmineraler?. Dagens næringsliv
Kommentar
Horni, K; Sørensen, Asgeir Johan; Johnsen, Geir; Ludvigsen, Martin. (2021) Internasjonalt forskningsmiljø dykker i Mjøsa etter at Oppland Arbeiderblad skrev om forurensning. Oppland arbeiderblad
Populærvitenskapelig artikkel
Mo-Bjørkelund, Tore; Majaneva, Sanna Kristiina; Moreira Fragoso, Glaucia; Johnsen, Geir; Ludvigsen, Martin. (2024) Multi-vehicle adaptive 3D mapping for targeted ocean sampling. PLOS ONE
Vitenskapelig artikkel
Jovine, R. V.; Johnsen, Geir; Prezelin, B. B.. (1995) Isolation of membrane bound chlorophyll a-chlorofhyll c binding light harvesting complexes from the dinoflagellates heterocapsa pygmaea and Prorocentrum minimum. Photosynthesis Research
Vitenskapelig artikkel
Jovine, R. V.; Schofield, O.; Johnsen, Geir; Prezelin, B. B.. (1994) Photoacclimatory differences in the light-harvesting complex of the bloom forming dinoflagellates Heterocapsa pygmaea and Prorocentrum minimum. Journal of Phycology
Vitenskapelig artikkel
Vernet, M.; Mitchell, B. G.; Sakshaug, Egil; Johnsen, Geir; Iturriaga, R.; Wassmann, P.. (1996) Evidence for a novel pigment with in vivo absorption maximum at 708 nm associated with Phaeocystis sp. blooms. Marine Ecology Progress Series
Vitenskapelig artikkel
Johnsen, Geir; Prezelin, B. B.; Jovine, R. V. M.. (1997) Fluorescence excitation spectra and light utiliation in two red tide dinoflagellates. Limnology and Oceanography
Vitenskapelig artikkel
Sakshaug, Egil; Johnsen, Geir; Andresen, Kjersti; Vernet, Maria. (1991) Modeling of light-dependent algal photosynthesis and growth: Experiments with the Barents Sea diatoms Thalassiosira nordensskioeldii and Chaetocero furcellatus. Deep-Sea Research Part II: Topical Studies in Oceanography
Vitenskapelig artikkel
Løvås, Håvard; Mogstad, Aksel Alstad; Sørensen, Asgeir Johan; Johnsen, Geir. (2021) A Methodology for Consistent Georegistration in Underwater Hyperspectral Imaging. IEEE Journal of Oceanic Engineering
Vitenskapelig artikkel
Faltynkova, Andrea; Deschenes, Catherine; Zolich, Artur; Wagner, Martin; Johansen, Tor Arne; Johnsen, Geir. (2024) Use of an uncrewed surface vehicle and near infrared hyperspectral imaging for sampling and analysis of aquatic microplastics. Marine Pollution Bulletin
Vitenskapelig artikkel
Johnsen, Geir; Sakshaug, Egil; Vernet, Maria. (1992) Pigment composition, spectral characteriation and photosynthetic parameters in Chrysochromulina polylepis. Marine Ecology Progress Series
Vitenskapelig artikkel
Johnsen, Geir; Hegseth, Else Nøst. (1991) Photoadaptation of sea-ice microalgae in the Barents Sea. Polar Biology
Vitenskapelig artikkel
Egeland, E.; Johnsen, Geir; Eikrem, W.; Jensen, S. Liaaen-; Throndsen, J.. (1995) The pigments of Bathycoccus prasinos. Journal of Phycology
Vitenskapelig artikkel
Schofield, O.; Prezelin, B. B.; Johnsen, Geir. (1996) Wavelength-dependency of maximum quantum yield of carbon fixation for two red tide dinoflagellates, Heterocapsa pygmaea and prorocentrum minimum. Journal of Phycology
Vitenskapelig artikkel
Johnsen, Geir; Sakshaug, Egil. (1996) Light harvesting in bloom-forming marine phytoplankton: Species-specifity and photoacclimation,. Scientia Marina
Vitenskapelig artikkel
Berge, Jørgen; Renaud, Paul E.; Johnsen, Geir; Darnis, Gerald; Geoffroy, Maxime; Daase, Malin; Kwasniewski, S; Draganska, K; Cottier, Finlo Robert; Falk-Petersen, Stig. (2016) I grenselandet (mellom Tull og Thule). Svalbardposten
Populærvitenskapelig artikkel
Gilstad, Mona; Johnsen, Geir; Sakshaug, Egil. (1993) Photosynthetic parameters, pigment composition and respiration rates of the marine diatom Skeletonema costatum grown in continuous light and a 12:1 light-dark cycle. Journal of Plankton Research
Vitenskapelig artikkel
Johnsen, Geir; Samset, O.; Granskog, L.; Sakshaug, Egil. (1994) In vivo absorption characteristics in 10 classes of phytoplankton: Taxonomic characteristics and responses to photoadaption by means of discriminant and HPLC analysis. Marine Ecology Progress Series
Vitenskapelig artikkel
Johnsen, Geir; Sakshaug, Egil. (1993) Bio-optical characteristics and photoadaptive responses in the toxic and bloomforming dinoflagellates Gyrodinium aureolum, Gymnodinium galatheanum two strains of Prorocentrum minium. Journal of Phycology
Vitenskapelig artikkel
Johnsen, Geir; Nelson, N. B.; Jovine, R. V. M.; Prezelin, B. B.. (1994) Chromoprotein- and pigment-dependent modeling of spectral light absorption in two dinoflagellates, Prorocentrum minimum and Heterocapsa pygmaea. Marine Ecology Progress Series
Vitenskapelig artikkel
Haugstad, Tor; Erdal, Ivar; Johnsen, Geir; Sørensen, Asgeir Johan; Fjærvik, Nils. (2016) Gründerne mener dette kameraet kan bli det nye ekkoloddet – Ecotone er kandidat til TU Tech Award. Teknisk Ukeblad
Populærvitenskapelig artikkel
Aarskog, Karine Nigar; Berge, Jørgen; Johnsen, Geir; Sørensen, Asgeir Johan. (2016) Et stort løft for arktisk forskning (NTNU & UiT). Universitetet i Tromsø
Fagartikkel
Haudemann-Andersen, Jørn; Lystad, M S; Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen. (2016) Blå lys i det kalde dyp. NRK Trøndelag, Nyheter
Populærvitenskapelig artikkel
Bazilchuk, Nancy Reney; Leite, Stein Roar; Johnsen, Geir; Kjeken, John; Sørensen, Asgeir Johan; Ludvigsen, Martin. (2016) Bomber og buss på havbunnen. Gemini
Populærvitenskapelig artikkel
Mogstad, Aksel Alstad; Johnsen, Geir. (2017) Spectral characteristics of coralline algae: a multi-instrumental approach, with emphasis on underwater hyperspectral imaging. Applied Optics
Vitenskapelig artikkel
Berge, Jørgen; Bakken, Torkild; Heggland, Kristin; Sneli, Jon-Arne; Ødegård, Øyvind; Ingulstad, Mats; Thun, Terje; Johnsen, Geir. (2025) Exploring Climate Change, Geopolitics, Marine Archeology, and Ecology in the Arctic Ocean Through Wood-Boring Bivalves. Oceanography
Vitenskapelig artikkel
Deschenes, C; Zolich, Artur; Wagner, Martin; Johnsen, Geir; Johansen, Tor Arne; Faltynkova, Andrea. (2023) Unmanned vehicle and hyperspectral imager for a more rapid microplastics sampling and analysis. OCEANS
Vitenskapelig artikkel
oudijk, AE; Johansen, Tor Arne; Johnsen, Geir; Alver, Morten Omholt. (2023) Simulating Hyperspectral Datacubes for Ocean Color: A Foundation for Phytoplankton Recognition in Spectral Signatures. OCEANS
Vitenskapelig artikkel
Johnsen, Geir. (2016) Yrende liv i Isfjorden. Svalbardposten
Populærvitenskapelig artikkel
Gabrielsen, Tove M; von Quillfeldt, Cecilie; Johnsen, Geir; Berge, Jørgen. (2012) Varm vinter, sen vår i fjorden. Svalbardposten
Kommentar
Berge, Jørgen; Cottier, Finlo; Varpe, Øystein; Renaud, Paul; Falk-Petersen, Stig; Kwasniewski, Sawomir; Griffiths, Colin; Søreide, Janne; Johnsen, Geir; Aubert, Anais; Bjærke, Oda; Hovinen, Johanna Emilia Heidi; Jung-Madsen, Signe; Tveit, Martha; Majaneva, Sanna. (2014) Arctic complexity: A case study on diel vertical migration of zooplankton. Journal of Plankton Research
Vitenskapelig artikkel
Krüger, Frida Jørstad; Johnsen, Geir; Kjeken, John; Ludvigsen, Martin. (2016) Gammel buss ble korallrev. NRK Viten
Populærvitenskapelig artikkel
Lervik, Frank; Johnsen, Geir; Ludvigsen, Martin; Kjeken, John. (2016) Det ligger flere busser der. Adresseavisen
Populærvitenskapelig artikkel
Bjørgan, Espen Halvorsen; Johnsen, Geir; Kjeken, Jon; Ludvigsen, Martin. (2016) Fant buss på 600 m dybde. Adresseavisen
Populærvitenskapelig artikkel
Berge, Jørgen; Falk-Petersen, Stig; Renaud, Paul E.; Daase, Malin; Geoffroy, Maxime; Johnsen, Geir. (2016) En reise mot Ultima Thule. Svalbardposten
Populærvitenskapelig artikkel
Cohen, Jonathan H.; Last, Kim; Charpentier, Corie L.; Cottier, Finlo; Daase, Malin; Hobbs, Laura; Johnsen, Geir; Berge, Jørgen. (2021) Photophysiological cycles in Arctic krill are entrained by weak midday twilight during the Polar Night. PLoS Biology
Vitenskapelig artikkel
Bazilchuk, Nancy Reney; Johnsen, Geir; Berge, Jørgen; Ludvigsen, Martin; Sørensen, Asgeir Johan; Ødegård, Øyvind. (2016) Mørkets fyrster, varulver og Indiana Jones. Gemini
Populærvitenskapelig artikkel
Neves, Luiza S.; Smeby, Kristin; Broch, Ole Jacob; Johnsen, Geir; Ardelan, Murat van; Skjermo, Jorunn. (2025) Particulate and dissolved organic carbon losses in high latitude seaweed farms. Science of the Total Environment
Vitenskapelig artikkel
Kokkegård, Hanne; Johnsen, Geir; Ludvigsen, Martin; Torre, Pedro De La. (2016) Vitenskab - Bomber fra 2 verdenskrig danner koralrev på 600 m dybde. Danmarks radio
Populærvitenskapelig artikkel
Moreira Fragoso, Glaucia; Dallolio, Alberto; Grant, Stephen Denis; Garrett, Joseph Landon; Ellingsen, Ingrid Helene; Johnsen, Geir; Johansen, Tor Arne. (2024) The Role of Rapid Changes in Weather on Phytoplankton Spring Bloom Dynamics From Mid-Norway Using Multiple Observational Platforms. Journal of Geophysical Research (JGR): Oceans
Vitenskapelig artikkel
Geoffroy, Maxime; Berge, Jørgen; Majaneva, Sanna Kristiina; Johnsen, Geir; Langbehn, Tom; Cottier, Finlo Robert; Mogstad, Aksel Alstad; Zolich, Artur Piotr; Last, Kim. (2018) Increased occurrence of the jellyfish Periphylla periphylla in the European high Arctic. Polar Biology
Vitenskapelig artikkel
Johnsen, Geir; Zolich, Artur; Grant, Stephen; Bjørgum, Rune; Cohen, Jonathan H.; Mckee, David; Kopec, Tomasz Piotr; Vogedes, Daniel Ludwig; Berge, Jorgen. (2021) All-sky camera system providing high temporal resolution annual time series of irradiance in the arctic. Applied Optics
Vitenskapelig artikkel
Elde, Anette; Pettersen, Ragnhild; Bruheim, Per; Järnegren, Johanna; Johnsen, Geir. (2012) Pigmentation and Spectral Absorbance Signatures in Deep-Water Corals from the Trondheimsfjord, Norway. Marine Drugs
Vitenskapelig artikkel
Legrand, Catherine; Johnsen, Geir; Graneli, Edna; Sakshaug, Egil. (2001) (Proceedings of the 9th International conference on Harmful Algal Blooms. Hobart, Tasmania, 7-11 February 2000.) Effect of polyamines on growth and toxicity of Chrysochromulina leadbeateri, Haptophytae. Phycologia
Vitenskapelig artikkel
Legrand, Catherine; Johansson, Niclas; Johnsen, Geir; Børsheim, Knut Yngve; Graneli, Edna. (2001) Phagotrophy and toxicity in the photosynthetic Prymnesium patelliferum (Haptophyte). Limnology and Oceanography
Vitenskapelig artikkel
Wägele, Heike; Johnsen, Geir. (2001) New results on histology and photosynthetic performance of solar-powered� opisthobranchs (Mollusca, Gastropoda, Opisthobranchia) containing symbiotic chloroplasts or zooxanthellae. Organisms Diversity & Evolution
Vitenskapelig artikkel
Nilssen, Ingunn; Ødegård, Øyvind; Sørensen, Asgeir Johan; Johnsen, Geir; Moline, Mark A.; Berge, Jørgen. (2015) Integrated environmental mapping and monitoring, a methodological approach to optimise knowledge gathering and sampling strategy. Marine Pollution Bulletin
Vitenskapelig artikkel
Graneli, Edna; Legrand, Catherine; Carlsson, Per; Johnsen, Geir; Maestrini, Serge Y.; Reichelt, Michael; Hummert, Christian; Luckas, Bernt; Pallon, Jan; Sakshaug, Egil. (2001) (Proceedings of the 9th International conference on Harmful Algal Blooms. Hobart, Tasmania, 7-11 February 20). Structuration of marine phytoplankton communities subjected to different levels of N, P and Si limitation in a mesocosm experiment (summary paper). Phycologia
Vitenskapelig artikkel
Gabrielsen, Tove M.; Johnsen, Geir. (2018) Skogen på Svalbard. Svalbardposten
Populærvitenskapelig artikkel
Thoen, Hanne Halkinrud; Johnsen, Geir; Berge, Jørgen. (2011) Pigmentation and spectral absorbance in the deep-sea arctic amphipods Eurythenes gryllus and Anonyx sp. Polar Biology
Vitenskapelig artikkel
Bakken, Sivert; Johnsen, Geir; Johansen, Tor Arne. (2021) Analysis and Model Development of Direct Hyperspectral Chlorophyll-A Estimation for Remote Sensing Satellites. Workshop on Hyperspectral Image and Signal Processing, Evolution in Remote Sensing
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir. (2016) Mørkets fyrster med påskrudd lys. Svalbardposten
Populærvitenskapelig artikkel
Johnsen, Geir. (2007) Arctic Life: Bridging ecosystem function using remote sensing technologies. Svalbard Science Forum
Populærvitenskapelig artikkel
Volent, Zsolt; Johnsen, Geir. (1992) Presentation of an optical sensor-"OPTISENS" designed for Eulerian measurements of Phytoplankton on a moored buoy. ABOOS (Autonomous Bio-Optical Observing Systems) Scientific Symposium : Abstracts
Vitenskapelig artikkel
Volent, Zsolt; Johnsen, Geir. (1993) Presentation of an optical sensor-"OPTISENS" designed for Eulerian measurements of Phytoplankton on a buoy. Underwater light measurements. Proceedings from International Symposium on high latitude optics.
Vitenskapelig artikkel
Seppala, J; Johnsen, Geir; Babichenko, S; Leeben, A; Poryvkina, L; Shalapyonok, [Mangler fornavn]. (1998) In vivo light absorption by photosynthetic and photoprotective algal pigments: Methodology and the effects of light acclimation and nutrient limitation. Report Series in Geophysics
Vitenskapelig artikkel
Johnsen, Geir; Dalløkken, Runar; Aure, J; Skjoldal, H. R. (1998) Photophysiology and environmental conditions during a toxic bloom of Chrysochromulina leadbeateri (Prymnesiophyceae). International symposium on Harmful Algal Blooms
Vitenskapelig artikkel
Johnsen, Geir. (1991) Identification of Chrysochromulina leadbeateri by means of remote sensing. Fisken og Havet
Vitenskapelig artikkel
Bordvik, Hans Otto; Johnsen, Geir. (2005) “En glupsk nellik”. NEWTON websider (NRK)
Populærvitenskapelig artikkel
Berge, Jørgen; Renaud, Paul; Darnis, Gérald; Cottier, Finlo; Last, Kim; Gabrielsen, Tove M.; Johnsen, Geir; Seuthe, Lena; Weslawski, Jan Marcin; Leu, Eva; Moline, Mark A.; Nahrgang, Jasmine; Søreide, Janne; Varpe, Øystein; Lønne, Ole Jørgen; Daase, Malin; Falk-Petersen, Stig. (2015) In the dark: a review of ecosystem processes during the Arctic polar night. Progress in Oceanography
Vitenskapelig artikkel
Berge, Jørgen; Daase, Malin; Renaud, Paul; Ambrose, William G. Jr.; Darnis, Gérald; Last, Kim S; Leu, Eva; Cohen, Jonathan H.; Johnsen, Geir; Moline, Mark A.; Cottier, Finlo; Varpe, Øystein; Shunatova, Natalia; Morata, Nathalie; Balazy, Piotr; Massabuau, Jean Charles; Falk-Petersen, Stig; Kosobokova, Ksenia; Hoppe, Clara J.M.; Weslawski, Jan Marcin; Kuklinski, Piotr; Legeżyńska, Joanna; Nikishina, Daria; Cusa, Marine; Kedra, Monika; Wlodarska-Kowalczuk, Maria; Vogedes, Daniel Ludwig; Camus, Lionel; Tran, Damien; Michaud, Emma; Gabrielsen, Tove M.; Granovitch, Andrei; Gonchar, Anya; Krapp, Rupert; Callesen, Trine A.. (2015) Unexpected levels of biological activity during the polar night offer new perspectives on a warming Arctic. Current Biology
Vitenskapelig artikkel
Båtnes, Anna Solvang; Miljeteig, Cecilie; Berge, Jørgen; Greenacre, Michael; Johnsen, Geir. (2013) Quantifying the light sensitivity of Calanus spp. during the polar night: potential for orchestrated migrations conducted by ambient light from the sun, moon, or aurora borealis. Polar Biology
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Ødegård, Øyvind. (2016) Mark spiser opp vrak på havbunnen. Fiskaren
Populærvitenskapelig artikkel
Bondø, Tor-Hartvig; Johnsen, Geir; Berge, Jørgen. (2016) Fant yrende liv i polarnatta. VG : Verdens gang
Populærvitenskapelig artikkel
Johnsen, Geir; Ludvigsen, Martin; Sørensen, Asgeir Johan; Aas, Lars Martin Sandvik. (2016) The use of underwater hyperspectral imaging deployed on remotely operated vehicle – methods and applications. IFAC-PapersOnLine
Vitenskapelig artikkel
Nymark, Marianne; Valle, Kristin Collier; Brembu, Tore; Winge, Per; Hancke, Kasper; Andresen, Kjersti; Johnsen, Geir; Bones, Atle M.. (2009) An integrated analysis of molecular acclimation to high light in the marine diatom Phaeodactylum tricornutum. PLOS ONE
Vitenskapelig artikkel
Bredholt, Harald; Fjærvik, Espen; Johnsen, Geir; Zotchev, Sergey. (2008) Actinomycetes from sediments in the Trondheim Fjord, Norway: Diversity and biological activity. Marine Drugs
Vitenskapelig artikkel
Aamot, Inga; Berge, Jørgen; Hancke, Kasper; Johnsen, Geir; Moline, Mark; Schofield, Oscar. (2010) NORUS - Technology Development for Marine Monitoring and Ocean Observation:An North America-Norway educational program. http://ipy-osc.no/abstract/
Konferanseabstract
Johnsen, Geir; Volent, Z; Tangen, K; Sakshaug, Egil. (1996) Time-series of potential toxic phytoplankton blooms in North European waters in 1993 using the SEAWATCH-Europe buoy system. EOS
Vitenskapelig artikkel
Jovine, R. V; Johnsen, Geir; Prezelin, B. B. (1994) Photoadaptation of Prorocentrum minimum and Heterocapsa pygmaea (Dinoflagellates): Chromoprotein changes and the consequenses for spectral absorption. EOS
Vitenskapelig artikkel
Sakshaug, Egil; Johnsen, Geir; Samset, Oddgeir; Zsolt, Volent. (1991) Identification of phytoplankton blooms by means of remote sensing. Environment Northern Seas
Vitenskapelig artikkel
Johnsen, Geir; Samset, Oddgeir; Zsolt, Volent. (1992) Bio-optical characteristicts of phytoplankton in relation to remote sensing. ABOOS (Autonomous Bio-Optical Observing Systems) Scientific Symposium : Abstracts
Vitenskapelig artikkel
Pettersen, Ragnhild; Johnsen, Geir; Berge, Jørgen; Hovland, Erlend Kjeldsberg. (2011) Phytoplankton chemotaxonomy in waters around the Svalbard archipelago reveals high amounts of Chl b and presence of gyroxanthin-diester. Polar Biology
Vitenskapelig artikkel
Thoen, Hanne Halkinrud; Johnsen, Geir; Berge, Jørgen. (2010) Pigmentation and spectral absorbance in the deep-sea arctic amphipods Eurythenes gryllus and Anonyx sp. Polar Biology
Vitenskapelig artikkel
Millie, D; Shofield, O. M; Kirkpatrick, G. J; Tester, P. A; Johnsen, Geir. (1996) Using bio-optical characterisics as bio-markers for harmful algal blooms: A case study of the Florida red-tide dinoflagellate,. EOS
Vitenskapelig artikkel
Johnsen, Geir; Candeloro, Mauro; Berge, Jørgen; Moline, Mark A.. (2014) Glowing in the dark: Discriminating patterns of bioluminescence from different taxa during the Arctic polar night. Polar Biology
Vitenskapelig artikkel
Indergaard, M; Nordtvedt, M; Johnsen, Geir. (2005) Satellittmålinger for miljøet (SISCAL project, NTNU, IBI). Gemini
Populærvitenskapelig artikkel
Bordvik, Hans Otto; Johnsen, Geir. (2005) “Forskning og foto under vann”. NEWTON websider (NRK)
Populærvitenskapelig artikkel
Hancke, Kasper; Hancke, Torunn Beate; Olsen, Lasse Mork; Johnsen, Geir; Glud, RN. (2008) Temperature effects on microalgal photosynthesis-light responses measured by O2 production, pulse-amplitude-modulated fluorescence, and C-14 assimilation. Journal of Phycology
Vitenskapelig artikkel
Grant, Stephen Denis; Johnsen, Geir; Mckee, David; Zolich, Artur Piotr; Cohen, Jonathan H.. (2023) Spectral and RGB analysis of the light climate and its ecological impacts using an all-sky camera system in the Arctic. Applied Optics
Vitenskapelig artikkel
Liu, Hongbo; Summers, Natalie Maria; Chen, Yi-Chun; Løvås, Håvard Snefjellå; Johnsen, Geir; Koestner, Daniel Warren; Sætre, Camilla; Hamre, Børge. (2024) Pixelwise immersion factor calibration for underwater hyperspectral imaging instruments. Optics Express
Vitenskapelig artikkel
Dumke, Ines; Ludvigsen, Martin; Ellefmo, Steinar Løve; Søreide, Fredrik; Johnsen, Geir; Murton, Bramley J.. (2018) Underwater Hyperspectral Imaging Using a Stationary Platform in the Trans-Atlantic Geotraverse Hydrothermal Field. IEEE Transactions on Geoscience and Remote Sensing
Vitenskapelig artikkel
Jouenne, Fabien; Eikrem, Wenche; Gall, F Le; Marie, Dominique; Johnsen, Geir; Vaulot, Daniel. (2011) Prasinoderma singularis sp. nov. (Prasinophyceae, Chlorophyta), a Solitary Coccoid Prasinophyte from the South-East Pacific Ocean. Protist
Vitenskapelig artikkel
Bakken, Torkild; Evertsen, Jussi; Johnsen, Geir. (2008) Vitenskapelig dykking - behov for endringer i forskriften. Dykkenytt : informasjonsorgan for dykkeindustrien
Fagartikkel
Johnsen, Geir; Søreide, Fredrik. (2010) Underwater hyperspectral imaging of marine mineral deposits. Underwater Mining meeting Institute (UMI)
Konferanseabstract
Jones, Alun; Utne, Ingrid Bouwer; Johnsen, Geir. (2025) Towards ecological integration into socio-technical risk assessment: A multidisciplinary system-theoretic approach. Ocean Engineering
Vitenskapelig artikkel
Gerland, Sebastian; Ingvaldsen, Randi Brunvær; Reigstad, Marit; Sundfjord, Arild; Bogstad, Bjarte; Chierici, Melissa; Hop, Haakon; Renaud, Paul E.; Smedsrud, Lars Henrik; Stige, Leif Christian; Årthun, Marius; Berge, Jørgen; Bluhm, Bodil A.; Borgå, Katrine; Bratbak, Gunnar; Divine, Dmitry V; Eldevik, Tor; Eriksen, Elena; Fer, Ilker; Fransson, Agneta; Gradinger, Rolf; Granskog, Mats A.; Haug, Tore; Husum, Katrine; Johnsen, Geir; Jonassen, Marius O.; Jørgensen, Lis Lindal; Kristiansen, Svein; Larsen, Aud; Lien, Vidar S.; Lind, Sigrid; Lindstrøm, Ulf; Mauritzen, Cecilie; Melsom, Arne; Mernild, Sebastian H.; Müller, Malte; Nilsen, Frank; Primicerio, Raul; Søreide, Janne E.; van der Meeren, Gro I.; Wassmann, Paul. (2023) Still Arctic? — The changing Barents Sea. Elementa: Science of the Anthropocene
Vitenskapelig oversiktsartikkel
Volent, Z; Johnsen, Geir; Sigernes, Fred. (2009) Microscopic hyperspectral imaging used as a bio-optical taxonomic tool for micro- and macroalgae. Applied Optics
Vitenskapelig artikkel
Carlsen, BP; Johnsen, Geir; Berge, Jørgen; Kuklinski, P. (2007) Biodiversity patterns of macro-epifauna on different lamina parts of Laminaria digitata and Saccharina latissima collected during spring and summer 2004 in Kongsfjorden, Svalbard. Polar Biology
Vitenskapelig artikkel
Connan-McGinty, Stacey; Banas, Neil S.; Berge, Jørgen; Cottier, Finlo Robert; Grant, Stephen; Johnsen, Geir; Kopec, Tomasz Piotr; Porter, Marie; Mckee, David. (2022) Midnight Sun to Polar Night: A Model of Seasonal Light in the Barents Sea. Journal of Advances in Modeling Earth Systems
Vitenskapelig artikkel
Millie, David; Schofield, Oscar; Kirkpatrick, Gary J.; Johnsen, Geir; Evens, Tim J.. (2002) Using absorbance and fluorescence spectra to discriminate microalgae. European journal of phycology
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Nilsen, Frank; Gulliksen, Bjørn; Slagstad, Dag. (2005) Ocean temperature oscillations enable reappearance of blue mussels Mytilus edulis in Svalbard after 1000 year absence. Marine Ecology Progress Series
Vitenskapelig artikkel
Bakken, Sivert; Luis, Kelly; Johnsen, Geir; Johansen, Tor Arne. (2023) Evaluating hyperspectral Secchi depth retrieval through hybrid modeling and regression. Workshop on Hyperspectral Image and Signal Processing, Evolution in Remote Sensing
Vitenskapelig artikkel
Volent, Z; Johnsen, Geir; Sigernes, Fred. (2007) Kelp forest mapping by use of airborne hyperspectral imager. Journal of Applied Remote Sensing
Vitenskapelig artikkel
Nymark, Marianne; Valle, Kristin Collier; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Bones, Atle M.; Brembu, Tore. (2013) Molecular and photosynthetic responses to prolonged darkness and subsequent acclimation to re-illumination in the diatom Phaeodactylum tricornutum. PLOS ONE
Vitenskapelig artikkel
Cronin, Heather; Cohen, Jonathan H.; Berge, Jørgen; Johnsen, Geir; Moline, Mark A.. (2016) Bioluminescence as an ecological factor during high Arctic polar night. Scientific Reports
Vitenskapelig artikkel
Hovland, Erlend Kjeldsberg; Hancke, Kasper; Alver, Morten; Drinkwater, Kennneth F.; Høkedal, Jo; Johnsen, Geir; Moline, Mark A.; Sakshaug, Egil. (2012) Optical impact of an Emiliania huxleyi bloom in the frontal region of the Barents Sea. Journal of Marine Systems
Vitenskapelig artikkel
Hancke, Kasper; Hovland, Erlend Kjeldsberg; Volent, Zsolt; Pettersen, Ragnhild; Johnsen, Geir; Moline, Mark A.; Sakshaug, Egil. (2012) Optical properties of CDOM across the Polar Front in the Barents Sea: Origin, distribution and significance. Journal of Marine Systems
Vitenskapelig artikkel
Chauton, Matilde Skogen; Optun, Odd Inge; Bathen, F. T; Volent, Z.; Gribbestad, Ingrid S.; Johnsen, Geir. (2003) HR MAS 1H NMR spectroscopy analysis of whole cells of marine microalgae. Marine Ecology Progress Series
Vitenskapelig artikkel
Figueroa, F. L.; Escassi, L.; Perez-Rodriguez, E.; Korbee, N.; Johnsen, Geir. (2003) Effects of the irradiance in the short-term on accumulation of mycosporine like amino acids in sun and shade species of the red algal genus Porphyra. Photochemistry and Photobiology
Vitenskapelig artikkel
Johansen, Torunn Beate; Johnsen, Geir. (2003) SISCAL End User Requirement evaluation document. www.siscal.net. Satellite-based Information System on Coastal Areas and Lakes. IST 2000
Vitenskapelig artikkel
Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H.; Torre, Pedro R. De La; Nornes, Stein Melvær; Singh, Hanumant; Sørensen, Asgeir Johan; Daase, Malin; Johnsen, Geir. (2018) Use of an autonomous surface vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance. Science Advances
Vitenskapelig artikkel
Johnsen, Geir; Candeloro, Mauro; Berge, Jørgen; Moline, Mark A.. (2014) Erratum to: Glowing in the dark: discriminating patterns of bioluminescence from different taxa during the Arctic polar night. Polar Biology
Korrigendum
Moreira Fragoso, Glaucia; Poulton, Alex J.; Yashayaev, Igor M.; Head, Erica J.H.; Johnsen, Geir; Purdie, Duncan A.. (2018) Diatom biogeography from the Labrador Sea revealed through a trait-based approach. Frontiers in Marine Science
Vitenskapelig artikkel
Evertsen, Jussi; Burghardt, Ingo; Johnsen, Geir; Wägele, Heike. (2007) Retention of functional chloroplasts in some sacoglossans from the Indo-Pacific and Mediterranean. Marine Biology
Vitenskapelig artikkel
Gileptis, Laura; Johnsen, Geir; Moxness, Helge; Norwich, Inger; Vangen, Steffen. (2002) Modul for mønstergjenkjenning/klassifisering i DynamicImager ved bruk av backpropagation-algoritmen. Piksel'n : Organ for NOBIM (Norsk forening for bildebehandling og mønstergjenkjenning)
Vitenskapelig artikkel
Grzymski, J.; Johnsen, Geir; Sakshaug, Egil. (1997) The significance of intracellular self-shadingon the bio-optical properties of brown, red and green macroalgal species. Journal of Phycology
Vitenskapelig artikkel
Valle, Kristin Collier; Nymark, Marianne; Aamot, Inga; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Brembu, Tore; Bones, Atle M.. (2014) System responses to equal doses of photosynthetically usable radiation of blue, green, and red light in the marine diatom Phaeodactylum tricornutum. PLOS ONE
Vitenskapelig artikkel
Günzel, Leonard Florian Tom; Osanen, Janina Emilia; Løvås, Håvard Snefjellå; Johnsen, Geir; Ortiz, Alberto García; Ludvigsen, Martin. (2025) Using Underwater Hyperspectral Imaging to Increase Feature Detection and Improve Under-Ice Navigation. IEEE Underwater Technology (UT)
Vitenskapelig artikkel
Vernet, M.; Mitchell, B.G.; Sakshaug, Egil; Johnsen, Geir; Iturriaga, R.; Wassmann, P.. (1996) Evidence for a novel pigment with in vivo absorption maximum at 708 nm associated with Phaeocystis cf. pouchetii blooms. Marine Ecology Progress Series
Vitenskapelig artikkel
Johnsen, Geir; Sakshaug, Egil. (1995) Light harvesting in bloom-forming marine phytoplankton: species-specificity and photoadaption. Scientia Marina
Vitenskapelig artikkel
Millie, D.; Schofield, O. M.; Kirkpatrick, G. J.; Johnsen, Geir; Tester, P. A.; Vinyard, B. T.. (1997) Phytoplankton pigments and absorption spectra as potential bio-markers for harmful algal blooms: A case study of the Florida red-tide dinoflagellat Gymnodinium breve. Limnology and Oceanography
Vitenskapelig artikkel
Grzymski, J.; Johnsen, Geir; Sakshaug, Egil. (1997) The significance of intracellular self-shading on the bio-optical properties of brown, red and green macroalgal species. Journal of Phycology
Vitenskapelig artikkel
Overrein, Martin Molberg; Tinn, Phil; Aldridge, David; Johnsen, Geir; Moreira Fragoso, Glaucia. (2024) Biomass estimations of cultivated kelp using underwater RGB images from a mini-ROV and computer vision approaches. Frontiers in Marine Science
Vitenskapelig artikkel
Ludvigsen, Martin; Sortland, Bjørn; Johnsen, Geir; Singh, Hanumant. (2007) Applications of Geo-Referenced Underwater Photo Mosaics in Marine Biology and Archaeology. Oceanography
Vitenskapelig artikkel
Berge, Jørgen; Båtnes, Anna Solvang; Johnsen, Geir; Blackwell, Susan; Moline, Mark A.. (2012) Bioluminescence in the high Arctic during the polar night. Marine Biology
Vitenskapelig artikkel
Geoffroy, Maxime; Langbehn, Tom Jasper; Priou, Pierre; Varpe, Øystein; Johnsen, Geir; Bris, Arnault Le; Fisher, Jonathan A. D.; Daase, Malin; Mckee, David; Cohen, Jonathan H.; Berge, Jørgen. (2021) Pelagic organisms avoid white, blue, and red artificial light from scientific instruments. Scientific Reports
Vitenskapelig artikkel
Johnsen, Geir; Eikrem, W.; Dalløkken, R.; Aure, J.; Skjoldal, H. R.. (1998) Physiology and environmental conditions during a toxic blooms of Chrysochromulina leadbeateri Prymnesiophyceae. Journal of Phycology
Vitenskapelig artikkel
Johnsen, Geir. (1991) Proceedings from a scientific working meeting. Fisken og Havet
Vitenskapelig artikkel
Nilssen, Ingunn; Santos, Francisco Dos; Coutinho, Ricardo; Gomes, Natalia; Cabral, Marcelo M.; Eide, Ingvar; Figueiredo, Marcia AO; Johnsen, Geir; Johnsen, Ståle. (2015) Assessing the potential impact of water-based drill cuttings on deep water calcareous red algae using species specific impact categories and measured oceanographic and discharge data. Marine Environmental Research
Vitenskapelig artikkel
Berge, Jørgen; Geoffroy, Maxime; Johnsen, Geir; Cottier, Finlo Robert; Bluhm, Bodil; Vogedes, Daniel Ludwig. (2016) Ice-tethered observational platforms in the Arctic Ocean pack ice. IFAC-PapersOnLine
Vitenskapelig artikkel
Ostaszewska, Kaja; Balazy, Piotr; Berge, Jørgen; Johnsen, Geir; Staven, Robert. (2017) Seabirds during Arctic Polar Night: underwater observations from Svalbard archipelago, Norway. Waterbirds (De Leon Springs, Fla.)
Vitenskapelig artikkel
Saad, Aya; Stahl, Annette; Våge, Andreas; Davies, Emlyn John; Nordam, Tor; Aberle-Malzahn, Nicole; Ludvigsen, Martin; Johnsen, Geir; Sousa, João; Rajan, Kanna. (2020) Advancing Ocean Observation with an AI-driven Mobile Robotic Explorer. Oceanography
Vitenskapelig artikkel
Assmy, Philipp; Fernández-Méndez, Mar; Duarte, Pedro; Meyer, Amelie; Randelhoff, Achim; Mundy, Christopher John; Olsen, Lasse Mork; Kauko, Hanna M.; Bailey, Allison; Chierici, Melissa; Cohen, Lana; Doulgeris, Anthony Paul; Ehn, Jens K.; Fransson, Agneta; Gerland, Sebastian; Hop, Haakon; Hudson, Stephen R.; Hughes, Nick; Itkin, Polona; Johnsen, Geir; King, Jennifer A.; Koch, Boris P.; Koenig, Zoe; Kwasniewski, Slawomir; Laney, Samuel R.; Nikolaus, Marcel; Pavlov, Alexey K.; Polashenski, Christopher M.; Provost, Christine; Rösel, Anja; Sandbu, Marthe; Spreen, Gunnar; Smedsrud, Lars H.; Sundfjord, Arild; Taskjelle, Torbjørn; Tatarek, Agnieszka; Wiktor, Josef; Wagner, Penelope Mae; Wold, Anette; Steen, Harald; Granskog, Mats A.. (2017) Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ic. Scientific Reports
Vitenskapelig artikkel
Moreira Fragoso, Glaucia; Poulton, Alex James; Pratt, Nicola Jane; Johnsen, Geir; Purdie, Duncan Alastair. (2019) Trait-based analysis of subpolar North Atlantic phytoplankton and plastidic ciliate communities using automated flow cytometer. Limnology and Oceanography
Vitenskapelig artikkel
Liefmann, Stephanie; Järnegren, Johanna; Johnsen, Geir; Murray, Fiona. (2018) Eco-physiological responses of cold-water soft corals to anthropogenic sedimentation and particle shape. Journal of Experimental Marine Biology and Ecology
Vitenskapelig artikkel
Berge, Jørgen; Johnsen, Geir; Sørensen, Asgeir Johan; Nilssen, Ingunn. (2015) Enabling technology for Arctic research. Pan European Networks: Science and Techology Magazine
Vitenskapelig oversiktsartikkel
Nilssen, Ingunn; dos, Francisco Santos; Coutinho, Ricardo; Gomes, Natalia; Montenegro, Marcelo Cabral; Eide, Ingvar; Figueiredo, Marcia; Johnsen, Geir; Johnsen, Ståle. (2015) Assessing the potential impact of water-based drill cuttings on deep-water calcareous red algae using species specific impact categories and measured oceanographic and discharge data. Marine Environmental Research
Vitenskapelig artikkel
Rodriguez, Francisco; Garrido, J.L.; Sabrino, C; Johnsen, Geir; Riobo, P; Franco, J; Aamot, Inga; Ramilo, I; Sanz, N; Kremp, Anke. (2015) Divinyl chlorophyll a in the marine eukaryotic protist Alexandrium ostenfeldii (Dinophyceae). Environmental Microbiology
Vitenskapelig artikkel
Dona, Angela; Evertsen, Jussi; Johnsen, Geir. (2022) The role of parapodia and lack of photoacclimation in kleptoplasts of the sacoglossan sea slug Plakobranchus ocellatus. Coral reefs
Vitenskapelig artikkel
Bakken, Sivert; Henriksen, Marie Bøe; Birkeland, Roger; Langer, Dennis David; Oudijk, Adriënne Esmeralda; Berg, Simen; Pursley, Yeshi Jampel; Garrett, Joseph Landon; Gran-Jansen, Fredrik; Honoré-Livermore, Evelyn; Grøtte, Mariusz Eivind Santora; Kristiansen, Bjørn Andreas; Orlandic, Milica; Gader, Paul; Sørensen, Asgeir Johan; Sigernes, Fred; Johnsen, Geir; Johansen, Tor Arne. (2023) HYPSO-1 CubeSat: First Images and In-Orbit Characterization. Remote Sensing
Vitenskapelig artikkel

Bøker

Sakshaug, Egil; Johnsen, Geir. (2005) Algal cultures, Analogues of Blooms and Applications. Multi-Science Publishing
Antologi
Syvertsen, E.; Hegseth, E; Johnsen, Geir; Sakshaug, Egil; Gulliksen, B; Lønne, O. J; Aarseth, A. (1992) Livet i isen (The life in the ice). In Økosystem Barentshavet. [Mangler utgivernavn]
Faglig monografi
Sakshaug, Egil; Kristiansen, S; Syvertsen, E; Eilertsen, H. C; Gilstad, M; Hegseth, E. N; Hewes, C; Holm-Hansen, O; Johnsen, Geir; Mitchell, B. G; Rey, F; Slagstad, D. (1992) Planktonalger (Phytoplankton). In Økosystem Barentshavet. [Mangler utgivernavn]
Faglig monografi

Del av bok/rapport

Sakshaug, E.; Johnsen, Geir; Kristiansen, Svein; Quillfeldt, C.v.; Rey, F.; Slagstad, D.; Thingstad, F.. (2009) Phytoplankton and primary production.
Vitenskapelig kapittel
Johnsen, Geir; Volent, Z; Sakshaug, E.; Sigernes, Fred; Pettersson, L.H.. (2009) Remote sensing in the Barents Sea.
Vitenskapelig kapittel
Johnsen, Geir; Volent, Z.; Tangen, K.; Sakshaug, Egil. (1997) Time series of harmful and benign phytoplankton blooms in northwest European waters using the Seawatch buoy system.
Vitenskapelig kapittel
Ødegård, Øyvind; Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Ekehaug, Stefan; Dukan, Fredrik; Moline, Mark A.. (2014) Managing data from multiple sensors in an interdisciplinary research cruise.
Vitenskapelig kapittel
Sakshaug, E.; Johnsen, Geir; Volent, Z. (2009) Light.
Vitenskapelig kapittel
Johnsen, Geir; Samset, O.; Sakshaug, Egil. (1998) Bio-optical classification of potential harmful chlorophyll c -containing prymnesiophyte blooms in Scandinavian water.
Vitenskapelig kapittel
Pavlov, Alexey K.; Leu, Eva; Hanelt, Dieter; Bartsch, Inka; Karsten, Ulf; Hudson, Stephen; Gallet, Jean-Charles; Cottier, Finlo Robert; Cohen, Jonathan H.; Berge, Jørgen; Johnsen, Geir; Maturilli, Marion; Kowalczuk, Piotr; Sagan, Slawomir; Meler, Justyna; Granskog, Mats. (2019) The Underwater Light Climate in Kongsfjorden and Its Ecological Implications.
Vitenskapelig kapittel
Johnsen, Geir; Moline, Mark; Pettersson, Lasse H.; Pinckney, J. L.; Pozdnyakov, Dmitry; Egeland, Einar Skarstad; Schofield, O. M.. (2011) Optical monitoring of phytoplankton bloom pigment signatures.
Vitenskapelig kapittel
Zolich, Artur Piotr; Faltynkova, Andrea; Johnsen, Geir; Johansen, Tor Arne. (2022) Portable Catamaran Drone - an uncrewed sampling vehicle for micro-plastics and aquaculture research.
Vitenskapelig kapittel
Berge, Jørgen; Johnsen, Geir; Cohen, Jonathan H.. (2020) Introduction.
Innledning i antologi
Cohen, Jonathan H.; Berge, Jørgen; Moline, Mark A.; Johnsen, Geir; Zolich, Artur Piotr. (2020) Light in the Polar Night.
Vitenskapelig kapittel
Zolich, Artur Piotr; Torre, Pedro R. De La; Rodwell, Shane; Geoffroy, Maxime; Johnsen, Geir; Berge, Jørgen. (2018) An ice-tethered buoy for fish and plankton research.
Vitenskapelig kapittel
Johnsen, Geir; Leu, Eva; Gradinger, Rolf. (2020) Marine Micro- and Macroalgae in the Polar Night.
Vitenskapelig kapittel
Berge, Jørgen; Johnsen, Geir; Last, Kim; Cohen, Jonathan H.; McKee, David. (2024) Light in polar regions.
Faglig kapittel
Berge, Jørgen; Johnsen, Geir. (2020) Life and Light at the Dead of Night.
Vitenskapelig kapittel
Sakshaug, Egil; Johnsen, Geir. (2005) Absorption, fluorescence excitation and photoacclimation in phytoplankton.
Vitenskapelig kapittel
Johnsen, Geir; Mogstad, Aksel Alstad; Berge, Jørgen; Cohen, Jonathan H.. (2020) Operative Habitat Mapping and Monitoring in the Polar Night.
Vitenskapelig kapittel
Johnsen, Geir; Volent, Zsolt; Dierssen, Heidi; Pettersen, Ragnhild; Ardelan, Murat Van; Søreide, Fredrik; Fearns, Peter; Ludvigsen, Martin; Moline, Mark A.. (2013) Underwater hyperspectral imagery to create biogeochemical maps of seafloor properties.
Vitenskapelig kapittel
Quillfeldt, Cecilie H. von; Hegseth, Else Nøst; Johnsen, Geir; Sakshaug, Egil; Syvertsen, Erik. (2009) Ice algae.
Vitenskapelig kapittel
Ludvigsen, Martin; Johnsen, Geir; Lågstad, Petter Arthur; Sørensen, Asgeir Johan; Ødegård, Øyvind. (2013) Scientific operations combining ROV and AUV in the Trondheim Fjord.
Vitenskapelig kapittel
Quillfeldt, C.v.; Hegseth, E.N.; Johnsen, Geir; Sakshaug, E.; Syvertsen, E.E.. (2009) Ice algae.
Vitenskapelig kapittel
Sakshaug, Egil; Johnsen, Geir; Kristiansen, Svein; von Quillfeldt, Cecilie; Rey, Francisco; Slagstad, Dag; Thingstad, Frede. (2009) Phytoplankton and primary production.
Vitenskapelig kapittel
Johnsen, Geir; Volent, Zsolt; Sakshaug, Egil; Sigernes, Fred; Pettersson, Lasse H.. (2009) Remote sensing in the Barents Sea.
Vitenskapelig kapittel
Sakshaug, Egil; Johnsen, Geir; Volent, Z.. (2009) Light.
Vitenskapelig kapittel
Roy, Suzanne; Llewellyn, Carole; Egeland, Einar Skarstad; Johnsen, Geir. (2011) Preface.
Innledning i antologi
Llewellyn, Carole A.; Roy, Suzanne; Johnsen, Geir; Egeland, Einar Skarstad; Chauton, Matilde; Hallegraeff, Gustaff; Lohr, Martin; Oster, Ulrike; Porra, Robert J.; Scheer, Hugo; Zhao, Kai-Hong. (2011) Perspectives on future directions.
Vitenskapelig kapittel
Ludvigsen, Martin; Thorsnes, Terje; Hansen, Roy Edgar; Sørensen, Asgeir Johan; Johnsen, Geir; Lågstad, Petter Arthur; Ødegård, Øyvind; Candeloro, Mauro; Nornes, Stein Melvær; Malmquist, Christian. (2015) Underwater vehicles for environmental management in coastal areas.
Vitenskapelig kapittel
von Quillfeldt, Cecilie; Hegseth, Else Nøst; Johnsen, Geir; Sakshaug, Egil; Syvertsen, Erik E.. (2009) Ice algae.
Vitenskapelig kapittel
Brunet, Christophe; Johnsen, Geir; Lavaud, Johan; Roy, Suzanne. (2011) Pigments and photoacclimation processes.
Vitenskapelig kapittel
Johnsen, Geir; Bricaud, Annick; Nelson, Norman; Prézelin, Barbara; Bidigare, Robert. (2011) In vivo bio-optical properties of phytoplankton pigments.
Vitenskapelig kapittel
Johnsen, Geir; Volent, Z.; Tangen, K.; Sakshaug, Egil. (1997) Time series of harmful and benign phytoplankton blooms in northwest European waters using the Seawatch buoy system.
Vitenskapelig kapittel

Rapport

Hancke, Kasper; Johnsen, Geir; Sakshaug, Egil. (2007) Bio-optical properties and spectral attenuation of photosynthetically available radiation: relation to primary productivity and phytoplankton composition. In Proceedings from Arctic Frontiers: balancing human use and ecosystem protection. UiT Norges arktiske universitet
Forskningsrapport
Johnsen, Geir; Volent, Zsolt; Sigernes, F.; Berge, Jørgen; Hovland, Erlend Kjeldsberg; Sakshaug, Egil. (2007) Local hyperspectral imaging of ocean colour from tethered balloons in the Arctic. In Proceedings from Arctic Frontiers: Balancing human use and ecosystem protection. UiT Norges arktiske universitet
Forskningsrapport
Johnsen, Geir. (2001) SISCAL End User Requirement Satellite-based Information System on Coastal Areas and Lakes. Information Society Technologies Programme funded by the European Comm
Forskningsrapport
Berge, Jørgen; Schander, C; Pampanin, D.M.; Johnsen, Geir. (2007) The past, present and future of the Mytilus edulis population on Svalbard. In Proceedings from Arctic Frontiers: Balancing human use and ecosystem protection. UiT Norges arktiske universitet
Forskningsrapport
Johnsen, Geir; Volent, Zsolt; Sigernes, F.. (2007) Fine scale studies using hyper-spectral remote sensing. ESSAS Meeting in Marine Arctic Climate
Forskningsrapport
Eldevik, Tor; Reigstad, Marit; Falck, Eva; Gerland, Sebastian; Jentoft, Sissel; Johnsen, Geir; Lindstrøm, Ulf; Rasmussen, Tine Lander; Røed, Lars Petter; Wassmann, Paul. (2014) Arven efter Nansen. Forskningsplan for det sentrale og nordlige Barentshavet. UiT Norges arktiske universitet
Forskningsrapport
Hancke, Torunn Beate; Johnsen, Geir. (2004) SISCAL processor evaluation document. www.siscal.net
Forskningsrapport
Johansen, Torunn Beate; Johnsen, Geir. (2002) End User requirement evaluation document. [Mangler utgivernavn]
Forskningsrapport
Johansen, Torunn Beate; Johnsen, Geir. (2002) End User Requirements document. [Mangler utgivernavn]
Forskningsrapport
Roy, Suzanne; Egeland, Einar Skarstad; Johnsen, Geir; Llewellyn, Carole; Wright, Simon. (2006) Report of a Workshop on a Follow-Up Volume of the Book "Phytoplankton Pigments in Oceanography". Scientific Committee on Oceanic Research
Forskningsrapport

Studentoppgave eller avhandling

Osanen, Janina Emilia; Moreira Fragoso, Glaucia; Johnsen, Geir. (2026) Use of novel optical and imaging technologies for the study of phytoplankton and sea ice algal dynamics across spatial and temporal scales. Norges teknisk-naturvitenskapelige universitet
Doktoravhandling
Johnsen, Geir; Nepstad, Ina. (2009) Cloning and characterisation of interleukin-6 and interleukin-11b in Atlantic halibut (Hippoglossus hippoglossus). NTNU, Institutt for biologi
Masteroppgave
Johnsen, Geir. (1994) Light Harvesting and Utiliation in Marine Phytoplankton: Species-Specific and Photoadaptive Responses. Dr. Scient. Thesis in Marine Botany, University of Trondheim
Doktoravhandling

Undervisning

Emner

Formidling

2026

Konferanseposter

Singh, Asmita; Moreira Fragoso, Glaucia; Osanen, Janina Emilia; Dallolio, Alberto; Johansen, Tor Arne; Ardelan, Murat van; Johnsen, Geir; Sanchez Puerto, Nicolas. (2026) From Satellites to Molecules: Resolving the Impacts of Snowmelt-Driven Runoff on Spring Phytoplankton Blooms in the Trondheim Fjord. Ocean Science Meeting
Konferanseposter

Moreira Fragoso, Glaucia; Osanen, Janina Emilia; Sanchez Puerto, Nicolas; Oudijk, Adrienne Esmeralda; Perumthuruthil Suseelan, Vishnu; Singh, Asmita; Dunshea, Glenn John; Gryte, Kristoffer; Torre, Pedro R. De La; Stevenson-Jones, Ralph; King, Dana Margareta; Skipenes, Pavel Germanjuk; Johnsen, Geir; Ardelan, Murat van; Johansen, Tor Arne. (2026) Using the ‘Observational Pyramid’Framework for High-Resolution Multi-Platform Monitoring of Autumn Phytoplankton Blooms in Trondheimsfjord-from eDNA to Hyperspectral Satellites. Ocean Sciences Meeting

2025

Aviskronikk

Berge, Jørgen; Bakken, Torkild; Heggland, Kristin; Ødegård, Øyvind; Ingulstad, Mats; Thun, Terje; Johnsen, Geir. (2025) Historien om et tre (og dets innbyggere).
Konferanseforedrag

Davidsen, Jan Grimsrud; Friis, Mikkel Emil Lange; Museth, Jon; Barron, Elizabeth Sanna; Ingulstad, Mats; Ødegård, Øyvind; Eikemo, Terje Andreas; Johnsen, Geir; Sørensen, Asgeir Johan; Ødegård, Rune Strand; Carson, Siri Granum; Sivertsen, Eirik Selnæs; Wroldsen, Jørn. (2025) Mission Mjøsa. 7. international conference on fish telemetry

2024

Konferanseposter

García, Laura Catherine Paiba; Johnsen, Geir; Bakken, Torkild. (2024) Biological diversity in the Norwegian basin: insights for the management of deep-sea mining. Nordic OIKOS 2024
Konferanseforedrag

García, Laura Catherine Paiba; Johnsen, Geir; Bakken, Torkild. (2024) The deep-sea: in numbers and pictures (related to deep-sea mining). NTNU Ocean talks
Aviskronikk

Ingulstad, Mats; Bakken, Torkild; Ellefmo, Steinar Løve; Johnsen, Geir; Hagspiel, Verena. (2024) Norge mangler kunnskap om gruvedrift i dyphavet.
Aviskronikk

Ingulstad, Mats; Bakken, Torkild; Johnsen, Geir; Ellefmo, Steinar Løve; Hagspiel, Verena. (2024) Norway needs to know much more before actually mining the deep sea.
Konferanseforedrag

Majaneva, Markus; Viljanen, Martta; Grant, Stephen Denis; Daase, Malin Hildegard Elisabeth; Geoffroy, Maxime; Langbehn, Tom; Johnsen, Geir; Majaneva, Sanna Kristiina. (2024) Illuminating zooplankton diel vertical migration with eDNA metabarcoding in the polar night. The 7th ICES/PICES Zooplankton Production Symposium
Konferanseposter

Singh, Asmita; Sanchez Puerto, Nicolas; Moreira Fragoso, Glaucia; Garrett, Joseph Landon; Johnsen, Geir; Johansen, Tor Arne; Ardelan, Murat van. (2024) Decoding Oceanic Mysteries: The Observational Pyramid for Insights into the Physical and Biogeochemical Changes in the Remote Polar Oceans. Antarktisseminaret 2024
Konferanseposter

Singh, Asmita; Sanchez Puerto, Nicolas; Moreira Fragoso, Glaucia; Garrett, Joseph Landon; Johnsen, Geir; Johansen, Tor Arne; Ardelan, Murat van. (2024) Enhancing Remote Polar Ocean Monitoring: Applying the Observational Pyramid for Improved Climate Insights. Digital Life Norway: Research School Conference
Konferanseposter

Viljanen, Martta; Five, Taran; Daase, Malin Hildegard Elisabeth; Hatlebakk, Maja Karoline Viddal; Johnsen, Geir; Majaneva, Sanna Kristiina. (2024) Species-specific light reactions of Arctic Calanus copepods revealed by AI assisted tracking. 15th International Congress of Neuroethology
Foredrag

Singh, Asmita; Sanchez Puerto, Nicolas; Moreira Fragoso, Glaucia; Garrett, Joseph Landon; Johnsen, Geir; Johansen, Tor Arne; Ardelan, Murat van. (2024) The Observational Pyramid: Unravelling the Physical and Biogeochemical Processes in the Remote Polar Oceans. Surface Ocean Lower Atmosphere (SOLAS) conference
Konferanseposter

Nevstad, Malin Bø; Johnsen, Geir; Bakken, Torkild; Løvås, Håvard Snefjellå. (2024) Using the observational pyramid for mapping of norwegian seagrass habitats. Ocean Optics 2024
Foredrag

Finstad, Anders Gravbrøt; Bakken, Torkild; Moreira Fragoso, Glaucia; Johnsen, Geir. (2024) Trondheimsfjorden, hva nå?. Hovedutvalg for natur, klima og beredskap, Trøndelag fylkeskommune
Konferanseforedrag

Majaneva, Markus; Viljanen, Martta; Grant, Stephen Denis; Daase, Malin Hildegard Elisabeth; Geoffroy, Maxime; Langbehn, Tom; Johnsen, Geir; Majaneva, Sanna Kristiina. (2024) Illuminating zooplankton diel vertical migration with eDNA metabarcoding in the polar night. BioStandards
Konferanseposter

Paiba Garcia, Laura Catherine; Johnsen, Geir; Bakken, Torkild. (2024) Exploring deep-sea benthos in the Greenland and Norwegian Seas: what may be affected by deep-sea mining?. British Ecological Conference 2024
Aviskronikk

Ingulstad, Mats; Bakken, Torkild; Ellefmo, Steinar Løve; Hagspiel, Verena; Johnsen, Geir. (2024) Feil på feil om gruvedrift på havbunnen - Stortingsmeldingen om gruvedrift på havbunnen holder ikke vann.
Konferanseposter

Viljanen, Martta; Majaneva, Sanna Kristiina; Majaneva, Markus; Daase, Malin Hildegard Elisabeth; Johnsen, Geir; Donner, Kristian; Lindström, Magnus. (2024) Arctic zooplankton in changing marine lightscape. Arctic Frontiers 2024 ACTIONS & REACTIONS
Konferanseforedrag

Bakken, Sivert; Johnsen, Geir; Johansen, Tor Arne. (2024) First Look at Mondrian Forests for Hyperspectral Secchi Depth Estimation. 13th EARSeL Workshop on Imaging Spectroscopy
Konferanseposter

Viljanen, Martta; Daase, Malin Hildegard Elisabeth; Majaneva, Markus; Donner, Kristian; Lindström, Magnus; Johnsen, Geir; Majaneva, Sanna Kristiina. (2024) Arctic zooplankton in changing marine lightscape. The 7th ICES/PICES Zooplankton Production Symposium 2024

2023

Aviskronikk

Sørensen, Asgeir Johan; Ludvigsen, Martin; Sivertsen, Eirik; Johnsen, Geir; Johansen, Tor Arne. (2023) Hvem skal samle inn, forvalte og ha tilgang til informasjon om havområdene?.
Aviskronikk

Sørensen, Asgeir Johan; Ludvigsen, Martin; Siversten, Eirik; Johnsen, Geir; Johansen, Tor Arne. (2023) Who should collect, manage and have access to data from the oceans?.
Aviskronikk

Sørensen, Asgeir Johan; Ludvigsen, Martin; Sivertsen, Eirik Selnæs; Johnsen, Geir; Johansen, Tor Arne. (2023) Hvem skal samle inn, forvalte og ha tilgang til informasjon om havområdene?.
Aviskronikk

Sørensen, Asgeir Johan; Ludvigsen, Martin; Sivertsen, Eirik Selnæs; Johnsen, Geir; Johansen, Tor Arne. (2023) Hvem skal samle inn, forvalte og ha tilgang til informasjon om havområdene?.
Konferanseposter

Lange, Benjamin Allen; Cimoli, Emiliano; Johnsen, Geir; Campbell, Karley Lynn; Osanen, Janina; Anhaus, Philipp; Summers, Natalie Maria; Granskog, Mats; Katlein, Christian; Matero, Ilkka; Marcel, Nicolaus. (2023) An Overview of Underwater Hyperspectral Imagery of Sea Ice in the Central Arctic Ocean. the Nansen Legacy Symposium
Konferanseposter

Hatlebakk, Maja Karoline Viddal; Viljanen, Martta; Grant, Stephen Denis; Johnsen, Geir. (2023) Behavioral Response in Calanus Copepods to Change in Ambient Light in the Polar Night. Nansen Legacy symposium: Towards a new Arctic Ocean - Past, Present, Future
Konferanseforedrag

Geoffroy, Maxime; Langbehn, Tom; McKee, David; Sandbank, Einat; Daase, Malin Hildegard Elisabeth; Vogedes, Daniel Ludwig; Varpe, Øystein; Priou, Pierre; Le Bris, Arnault; Fisher, JA; Cohen, Jonathan H.; Johnsen, Geir; Berge, Jørgen. (2023) Pelagic organisms avoid artificial light from scientific instruments. Svalbard Science Conference
Konferanseforedrag

Geoffroy, Maxime; Langbehn, Tom; Mckee, David; Sandbank, Einat; Daase, Malin Hildegard Elisabeth; Vogedes, Daniel Ludwig; Priou, Pierre; Le Bris, Arnault; Fisher, JA; Cohen, Jonathan H.; Varpe, Øystein; Johnsen, Geir; Berge, Jørgen. (2023) Pelagic organisms avoid white, blue, green, and red artificial light from scientific instruments. ICES Symposium on Fisheries Acoustics
Konferanseposter

Reigstad, Marit; Gerland, Sebastian; Eldevik, Tor; Kunisch, Erin; Wiedmann, Ingrid; Sundfjord, Arild; Bluhm, Bodil Annikki Ulla Barbro; Li, Camille; Nilsen, Frank; Johnsen, Geir; Hansen, Håvard; Christensen, Kai Håkon; Årthun, Marius; Ludvigsen, Martin; Forwick, Matthias; Chierici, Melissa; Skogen, Morten D.; Godøy, Øystein Arne; Ingvaldsen, Randi Brunvær; Jentoft, Sissel; Gabrielsen, Tove M.. (2023) The Nansen Legacy project invites you to its upcoming international symposium in November 2023. Alaska Marine Science Symposium
Aviskronikk

Carson, Siri Granum; Munro, Bjoern Jenssen,; Johnsen, Geir; Mason, Arthur. (2023) En bærekraftig fremtid for Svalbard – er utvinning av dyphavsmineraler en del av svaret?.
Konferanseforedrag

Viljanen, Martta; Daase, Malin Hildegard Elisabeth; Hatlebakk, Maja Karoline Viddal; Johnsen, Geir. (2023) Behavioral light responses vary between different species of Arctic zooplankton. Visionarium XXI
Intervju

Nordahl, A; Dugstad, L; Magnussen, O; Bakken, JB; Johnsen, Geir. (2023) Laksegriseriet.

2022

Foredrag

Zolich, Artur Piotr; Faltynkova, Andrea; Johnsen, Geir; Johansen, Tor Arne. (2022) Portable Catamaran Drone - an uncrewed sampling vehicle for micro-plastics and aquaculture research. MTS/IEEE OCEANS
Konferanseforedrag

Dona, Angela; Evertsen, Jussi; Johnsen, Geir. (2022) Lack of kleptoplast photoacclimation and the role of parapodia in the sacoglossan sea slug Plakobranchus ocellatus. 15th International Coral Reef Symposium
Foredrag

Oudijk, Esmée; Hasler, Oliver Kevin; Overaas, H; Marty, Sabine; Williamson, David; Svendsen, T; Berg, Simen; Birkeland, Roger; Halvorsen, D; Bakken, S; Henriksen, Marie Bøe; Alver, Morten; Johnsen, Geir; Johansen, Tor Arne; Stahl, Annette; Kvaløy, Pål; Dallolio, Alberto; Majaneva, Sanna; Moreira Fragoso, Glaucia; Garrett, Joseph. (2022) Campaign For Hyperspectral Data Validation In North Atlantic Coastal Waters. 2022 12th Workshop on Hyperspectral Imaging and Signal Processing: Evolution in Remote Sensing (WHISPERS)

2021

Konferanseforedrag

Geoffroy, Maxime; Langbehn, Tom; Varpe, Øystein; Cohen, Jonathan H.; Cottier, Finlo; Last, Kim S; Johnsen, Geir; Mckee, David; Daase, Malin Hildegard Elisabeth; Berge, Jørgen. (2021) In situ experiments reveal behavioral response of marine fish and zooplankton when exposed to artificial light during the Arctic polar night. ICES 2021 Annual Science Conference
Konferanseforedrag

Geoffroy, Maxime; Langbehn, Tom; Varpe, Øystein; Cohen, Jonathan H.; Cottier, Finlo; Last, Kim S; Johnsen, Geir; McKee, David; Daase, Malin Hildegard Elisabeth; Berge, Jørgen. (2021) Behavioral response of marine fish and zooplankton exposed to artificial light during acoustic surveys. Arctic Science Summit Week

2020

Konferanseforedrag

Johnsen, Geir. (2020) Centre of Autonomous Marine Operations & Systems (AMOS) - selcted research activities. PRIME + EELS Ocean Worlds Arctic Collaboration (OWAC) Workshop
Konferanseforedrag

Bakken, Sivert; Wei, J; Lee, Z; Johnsen, Geir; Johansen, Tor Arne; Montoya, J; Subramaniam, Ajit. (2020) Hyperspectral Remote Sensing of the Amazon River Plume. Ocean Science Meeting
Intervju

Gibbens, Sarah; Berge, Jørgen; Johnsen, Geir; Mckee, David. (2020) As the Arctic warms, light pollution may pose a new treat to marine life.

2019

Konferanseforedrag

Ødegård, Øyvind; Johnsen, Geir; Sørensen, Asgeir Johan; Ludvigsen, Martin; Geoffroy, Maxime; Berge, Jørgen. (2019) Shipwrecks in the Arctic – knowledge gaps illustrated by a case from Svalbard. ArcticNet Anuual Scientific Meeting 2019

2018

Foredrag

Johnsen, Geir. (2018) Polar night - light as a cue of life. Seminar at Hawaiian Inst of marine biology (HIMB), University of Hawaii at Manoa
Konferanseforedrag

Johnsen, Geir. (2018) Underwater hyperspectral imaging for marine biological applications. Seminar at University of Hawaii at Manoa
Foredrag

Johnsen, Geir. (2018) Light as a cue for life - Arctic. Kunstakademiet - invitert foredrag
Foredrag

Johnsen, Geir; Berge, Jørgen; Sørensen, Asgeir Johan. (2018) Marin polarnatt. 30 årsjubileum Vitensenteret i Trondheim
Foredrag

Johnsen, Geir. (2018) Light as a cue of life - Arctic. Arktis
Foredrag

Johnsen, Geir; Berge, Jørgen. (2018) Polarnatt. Polarnatts seminar med muliggjørende teknologi
Konferanseforedrag

Johnsen, Geir; Berge, Jørgen; Sørensen, Asgeir Johan. (2018) Enabling technology fort marine ecology. Conference
Konferanseforedrag

Davies, Emlyn John; Moreira Fragoso, Glaucia; Johnsen, Geir; Ellingsen, Ingrid H.. (2018) Combining optics, imaging and artificial intelligence for in-situ characterisation of complex particle populations. AGU Ocean Sciences
Aviskronikk

Berge, Jørgen; Johnsen, Geir. (2018) Lysforurensning - enda en kilde til bekymring.
Aviskronikk

Berge, Jørgen; Johnsen, Geir. (2018) Lysforurensning truer livet i Arktis.

2017

Konferanseposter

Geoffroy, Maxime; Berge, Jørgen; Majaneva, Sanna Kristiina; Johnsen, Geir; Cottier, Finlo Robert. (2017) First records of Periphylla periphylla in a high Arctic fjord: a newcomer or a returning visitor?. Gordon Reserach Conference in Polar Marine Science
Foredrag

Geoffroy, Maxime; Berge, Jørgen; Majaneva, Sanna Kristiina; Johnsen, Geir; Cottier, Finlo Robert. (2017) First records of Periphylla periphylla in a high Arctic fjord: a newcomer or a returning visitor?. Gordon Research Seminar in Polar Marine Science
Konferanseforedrag

Berge, Jørgen; Johnsen, Geir; Torre, Pedro De La. (2017) Field activities in Kongsfjorden and relations between ice cinditions, light climate and ecosystem dynamics. Resice project-Arctic 2030 - seminar
Foredrag

Geoffroy, Maxime; Berge, Jørgen; Falk-Petersen, Stig; Johnsen, Geir; Hernandez, Nestor Santana; Cusa, Marine Lure Joana; Daase, Malin; Bluhm, Bodil; Graeve, Martin; Cottier, Finlo Robert. (2017) Northward range expansion of boreal species into the Arctic: further evidences from the polar night. ArcticChange conference
Aviskronikk

Johnsen, Geir; Christiansen, Hanne H; Ravolainen, Virve; Reymert, Per Kyrre; Jenssen, Eva Therese; Arlov, Thor Bjørn; Dybdahl, Jørn. (2017) Utfordrende natur og sikkerhet på Svalbard.
Konferanseforedrag

Johnsen, Geir. (2017) Kunnskapsgenerering, kartlegging og overvåkning I nordområdene med autonome systemer. Norges Teknisk Vitenskapsakademi (NTVA) årsmøte
Intervju

Otterlei, Inger; Johnsen, Geir; Sørensen, Asgeir Johan; Ludvigsen, Martin; Hareide, Nils Roar; Christensen-Dalsgaard, Signe. (2017) 300 000 sjøfugl er forsvunnet fra Runde.
Konferanseposter

Kauko, Hanna M.; Taskjelle, Torbjørn; Assmy, Philipp; Pavlov, Alexey; Mundy, C J; Duarte, Pedro; Fernández-Méndez, Mar; Olsen, Lasse Mork; Hudson, S R; Elliott, A; Peeken, Ilka; Johnsen, Geir; Wang, F; Granskog, M A. (2017) Windows in Arctic sea ice – light transmission and ice algal response in a refrozen lead. ESSAS international open science meeting, Tromsø, Norway,
Konferanseforedrag

Johnsen, Geir. (2017) Hyperspectral imaging above and in water – applications. Small Satellite Seminar
Konferanseforedrag

Johnsen, Geir. (2017) Use of enabling technology for marine science applications. SFF AMOS og FFI Seminar
Konferanseposter

Moreira Fragoso, Glaucia; Davies, Emlyn John; Ellingsen, Ingrid H.; Ludvigsen, Martin; Johnsen, Geir. (2017) Assessing phytoplankton and zooplankton dynamics using optical sensors. Aquafluor II Conference in Sydney
Konferanseforedrag

Johnsen, Geir. (2017) Can novel technologies revolutionise the montoring regime in sea-based aquaculture?. Ocean Week Conference, Trondheim
Konferanseposter

Zolich, Artur Piotr; Johnsen, Geir; Berge, Jørgen; Hagan, Bernard. (2017) Ny Ålesund light observatory experiment – from polar night to midnight sun. Arctic Change Conference, Quebec City, Canada
Konferanseposter

Kauko, Hanna M.; Mundy, C J; Granskog, M A; Peeken, Ilka; Johnsen, Geir; Ehn, Jens K.; Assmy, Philipp. (2017) Ice algal pigments in thin Arctic sea ice: Trends and correlation to transmitted irradiance. Gordon research conference on Polar marine sciences, Ventura, USA
Konferanseforedrag

Johnsen, Geir. (2017) Bruk av ny teknologi for marine økosystemobservasjoner i luft og vann. Workshop - planlegging av Runde kartlegging, overvåkning og tokt i juni 2017
Konferanseforedrag

Johnsen, Geir; Ludvigsen, Martin; Sørensen, Asgeir Johan. (2017) Enabling technology for marine ecology studies. Official meeting between University of Porto and NTNU
Konferanseforedrag

Johnsen, Geir; Berge, Jørgen; Zolich, Artur Piotr. (2017) . Light observatory in Ny Ålesund. Arctic ABC Seminar at NTNU
Konferanseforedrag

Johnsen, Geir. (2017) Polar night – past, present and future – A view for nature management and decision making. The Henningsvær charter, Henningsvær 28-30th Sep 2017.
Konferanseforedrag

Berge, Jørgen; Johnsen, Geir. (2017) Life and light in the dead of night. Science Week in Moscow
Konferanseforedrag

Ludvigsen, Martin; Sørensen, Asgeir Johan; Johnsen, Geir. (2017) Autonomous technology in marine environment mapping and monitoring. Autonomous Vehicles for ocean monitoring
Aviskronikk

Berge, Jørgen; Johnsen, Geir. (2017) Superkommunisten.
Aviskronikk

Berge, Jørgen; Johnsen, Geir. (2017) Om bambus, spøkelseskreps og et Arktis i endring.
Konferanseforedrag

Johnsen, Geir; Moreira Fragoso, Glaucia; Davies, Emlyn John; Sørensen, Asgeir Johan; Ludvigsen, Martin; Berge, Jørgen. (2017) Use of optical sensors to identify, map and monitor phyto- and zooplankton. Arctic change conference, Quebec City, Canada
Konferanseforedrag

Johnsen, Geir; Berge, Jørgen; Sørensen, Asgeir Johan; Ludvigsen, Martin. (2017) Use of autonomous platforms in the Arctic. Seminar at Norges Vitenskapsakademi for polarforskning og Norges tekniske vitenskapsakademi.
Aviskronikk

Berge, Jørgen; Johnsen, Geir. (2017) Kunnskapshull om livet i Arktis i mørketiden.

2016

Intervju

Kintisch, Eli; Berge, Jørgen; Last, Kim; Cohen, Jonathan; Johnsen, Geir. (2016) Voyage into darkness.
Intervju

Bazilchuk, Nancy Reney; Johnsen, Geir; Berge, Jørgen; Sørensen, Asgeir Johan; Ødegård, Øyvind. (2016) Dark lords, werewolves and Indiana Jones in the polar night.
Aviskronikk

Berge, Jørgen; Johnsen, Geir; Ludvigsen, Martin; Cohen, Jonathan. (2016) Design for latskap - men med store muligheter.
Intervju

Haugstad, Tormod; Erdal, Ivar; Johnsen, Geir. (2016) Kameraet deres «kan bli det nye ekkoloddet». Nå er det norske selskapet i ferd med å lykkes.
Aviskronikk

Berge, Jørgen; Johnsen, Geir; Ødegård, Øyvind. (2016) Kinderegg i polarnatten.
Aviskronikk

Berge, Jørgen; Ødegård, Øyvind; Johnsen, Geir. (2016) Opp fra polarnattens mørke.
Aviskronikk

Berge, Jørgen; Ødegård, Øyvind; Johnsen, Geir. (2016) A bitter-sweet symphony.
Foredrag

Søreide, Janne E.; Gradinger, Rolf; Niehoff, Barbara; Bluhm, Bodil; Gabrielsen, Tove M.; Peeken, Ilka; Johnsen, Geir; Berge, Jørgen. (2016) Arctic Ocean winter ecology – the Big Black Box. 3rd Arctic Observing Summit

2015

Konferanseforedrag

Ludvigsen, Martin; Thorsnes, Terje; Hansen, Roy Edgar; Sørensen, Asgeir Johan; Johnsen, Geir; Lågstad, Petter Arthur; Candeloro, Mauro; Nornes, Stein Melvær; Malmquist, Christian. (2015) Underwater vehicles for environmental management in coastal areas. OCEANS 2015
Konferanseposter

Vogedes, Daniel Ludwig; Berge, Jørgen; Daase, Malin; Johnsen, Geir; Darnis, Gérald; Last, Kim S.; Moline, Mark A.; Renaud, Paul; Leu, Eva; Morata, Nathalie; Gabrielsen, Tove M.; Shunatova, Natalia; Varpe, Øystein; Sørensen, Asgeir Johan; Cottier, Finlo; Weslawski, Jan Marcin; Kuklinski, Piotr; Balazy, Piotr; Nahrgang, Jasmine; Falk-Petersen, Stig. (2015) Expect the unexpected - a new perspective and understanding of marine life at high latitudes. Gordon Research Conference and Seminar on Polar Marine Science

2014

Konferanseforedrag

Bones, Atle M.; Nymark, Marianne; Valle, Kristin Collier; Winge, Per; Brembu, Tore; Johnsen, Geir; Hancke, Kasper; Aamot, Inga; Andresen, Kjersti. (2014) System responses to equal doses of photosynthetically usable radiation of blue, green and red light in the diatom Phaeodactylum tricornutum. SEB 2014
Foredrag

Johnsen, Geir. (2014) Perspektiv fra en faglig ansatt. Strategiske partnerskap og allianser – hva får vi ut av dem – case NORUS. Internasjonaliseringskonferansen 2014, Trondheim 5-6 mars 2014
Konferanseforedrag

Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen. (2014) Underwater robots & sensors in the Polar night. Worshop in underwater robotics
Konferanseforedrag

Ødegård, Øyvind; Johnsen, Geir; Sørensen, Asgeir Johan. (2014) Use of Underwater Hyperspectral Imager (UHI) in Marine Archaeology. Ocean Optics XXII
Foredrag

Johnsen, Geir; Berge, Jørgen. (2014) Varulvene kommer!. Svalbard seminaret
Konferanseforedrag

Johnsen, Geir. (2014) KOMPiS (Kompetanse i Skolen) Biodiversitet - Trondheimsfjorden. Kompetanse i skolen (KOMPiS)
Konferanseforedrag

Johnsen, Geir. (2014) Underwater hyperspectral imagery for seafloor mapping - now and future perspectives. Seminar at Curtin University, Perth Western Australia
Foredrag

Johnsen, Geir; Sørensen, Asgeir Johan; Berge, Jørgen. (2014) Varulver i polarnatta. NTVA-/NVP-seminar i Trondheim
Konferanseforedrag

Johnsen, Geir; Berge, Jørgen. (2014) "Varulvene kommer". Seminar Norw Academy of Polar Res (NAPR) & Techn Sci (NTVA)

2013

Konferanseforedrag

Johnsen, Geir; Hansen, Ingrid; Ekehaug, Stefan. (2013) Identification, mapping & monitoring of underwater habitats using Underwater Hyperspectral Imager (UHI) on robots. Workshop on sea bed habitats of environmental concern
Konferanseforedrag

Ødegård, Øyvind; Sørensen, Asgeir Johan; Johnsen, Geir. (2013) Towards Autonomy in Marine Archaeology. Nordisk Konference for Marinarkæologi
Foredrag

Johnsen, Geir. (2013) Trondheimsfjordens hemmeligheter. Kunnskapsbyen
Foredrag

Johnsen, Geir. (2013) Trondheimsfjordens hemmeligheter - i dypet. Trondheim Rotary Klub
Foredrag

Johnsen, Geir. (2013) Undervannsroboter i Trondheimsfjorden. Forskningsdagene i Trondheim
Konferanseforedrag

Johnsen, Geir. (2013) Marine Arctic environment- a quick overview. Workshop in underwater technology & operations, UNIS 10-12 April 2013
Konferanseforedrag

Johnsen, Geir; Hansen, Ingrid Myrnes; Ekehaug, Stefan. (2013) Identification, mapping and monitoring of underwater habitats using underwater hyperspectral imager on robots. Workshop on Sea Bed Habitats of Environmental Concern 2013
Konferanseforedrag

Johnsen, Geir; Ludvigsen, Martin; Sørensen, Asgeir Johan; Moline, Mark A.. (2013) Underwater hyperspectral imagery for identification, mapping and monitoring of bio-geo-chemical features on the sea floor. Blue Photonics 3
Konferanseforedrag

Ludvigsen, Martin; Låge, Petter A.; Johnsen, Geir; Sørensen, Asgeir Johan; Ødegård, Øyvind. (2013) Scientific operations combining ROV and AUV in the Trondheim Fjord. OCEANS’13
Konferanseforedrag

Johnsen, Geir; Sørensen, Asgeir Johan. (2013) Ny teknologi for utforskning av havrommet. Årssamling FHL Midtnorsk Havbrukslag
Konferanseforedrag

Johnsen, Geir; Sørensen, Asgeir Johan. (2013) Underwater remote sensing – mapping & monitoring of marine life. Workshop on habitat mapping and time-series in coastal Norway and Svalbard
Konferanseforedrag

Johnsen, Geir; Moline, Mark A.; Ludvigsen, Martin; Berge, Jørgen; Sørensen, Asgeir Johan. (2013) Use of underwater robots and sensors to identify, map, monitor biomass & production in the Arctic. Arctic Frontiers

2012

Konferanseforedrag

Johnsen, Geir; Sørensen, Asgeir Johan. (2012) UHI based mapping of habitats and organisms on the seabed. International workshop on seabed mapping methods and technology
Konferanseforedrag

Båtnes, Anna Solvang; Miljeteig, Cecilie; Berge, Jørgen; Johnsen, Geir. (2012) Light responses of Arctic zooplankton during the polar night. Ocean Optics Conference XXI
Konferanseforedrag

Johnsen, Geir. (2012) Marine biology and TBS- Marine underwater robots & sensors. NTNU Marine Science Seminar
Konferanseforedrag

Johnsen, Geir; Sørensen, Asgeir Johan. (2012) NTNU´s kobling naturvitenskap/teknologi gir nøkkelrolle for havrom-utforskning via NTNU MCD. NTNU Marine coastal development strategiseminar
Foredrag

Johnsen, Geir. (2012) Marine undervannsroboter og sensorer til havovervåkning. Luncheseminar Institutt for biologi
Foredrag

Johnsen, Geir; Sørensen, Asgeir Johan. (2012) Marine undervannsroboter og sensorer til havovervåkning. Luncheseminar Gløshaugen Akademiske Klubb, NTNU
Konferanseforedrag

Johnsen, Geir; Moline, Mark A.; Berge, Jørgen; Sørensen, Asgeir Johan. (2012) Underwater mapping and monitoring in the Arctic. Workshop in Underwater Technology and operations. Workshop in Underwater Technology and operations
Konferanseforedrag

Johnsen, Geir; Moline, Mark A.; Berge, Jørgen; Schofield, Oscar. (2012) Technology and science development for marine monitoring and ocean observation. Workshop in Underwater Technology and operations
Konferanseforedrag

Hovland, Erlend Kjeldsberg; Dierssen, Heidi; Johnsen, Geir. (2012) Emiliania huxleyi in the Barents Sea. Ocean Optics Conference XXI
Konferanseforedrag

Johnsen, Geir. (2012) In situ and remote sensing of phytoplankton pigments – some examples of detecting pigment-signatures using different platforms and optical sensors. Final PROTOOL meeting at SYKE – “Marine Environmental Monitoring Methods
Konferanseforedrag

Båtnes, Anna Solvang; Berge, Jørgen; Johnsen, Geir; Miljeteig, Cecilie. (2012) In situ light responses of high Arctic Calanus spp. Ocean Optics 2012
Konferanseforedrag

Ødegård, Øyvind; Ludvigsen, Martin; Johnsen, Geir; Sørensen, Asgeir Johan; Ekehaug, Stefan; Dukan, Fredrik; Moline, Mark A.. (2012) Managing data from multiple sensors in an interdisciplinary research cruise. CAA 2012 (Computer Applications and Quantitative Methods in Archaeology )
Foredrag

Johnsen, Geir. (2012) Trondheimsfjordens hemmeligheter – I dypet. Kunnskapsbyen, NTNU
Leserinnlegg

Gabrielsen, Tove M.; von Quillfeldt, Cecilie; Johnsen, Geir; Berge, Jørgen. (2012) Varm vinter, sen vår i fjorden.

2011

Konferanseforedrag

Johnsen, Geir. (2011) The use of a underwater hyperspectral imager to map and monitor bio-geo-chemical object of interest on seafloor. Australian Meterological & Oceanographic Society symposium
Konferanseforedrag

Johnsen, Geir. (2011) The use of a underwater hyperspectral imagery to map bio-geo-chemical objects of interest on seafloor. Imaging and Phycics seminar series.
Konferanseforedrag

Johnsen, Geir. (2011) Underwater hyperspectral imaging of Great Barrier Reef corals. Lizard Island Research seminar, Australian Museum
Konferanseforedrag

Lynch, Mervin; Hedley, John; Klonowski, Wojchiech; Slivkoff, Matt; Johnsen, Geir; Fearns, Peter; Marrable, Dan. (2011) Remote sensing of the eutrophic state of coastal waters via phytoplankton functional groups. International Symposium on Remote Sensing of Environment
Konferanseforedrag

Johnsen, Geir. (2011) The use of underwater robotics and underwater hyperspectral imagery to map and monitor marine bio-diversity. School of Biology Sciences seminars
Konferanseforedrag

Berge, Jørgen; Moline, Mark; Johnsen, Geir. (2011) NORUS – Research-based educational field studies using new sensors for mapping of water surface, column and sea-floor. Transatlantic Science Week, UC Berkeley
Foredrag

Johnsen, Geir. (2011) Romteknologi under havoverflaten – Undervannsroboter med optiske sensorer for deteksjon av bio-geo-kjemiske objekter av interesse. Havforskermøte 2011
Konferanseforedrag

Moline, Mark A.; Johnsen, Geir; Berge, Jørgen. (2011) Technology Development for marine monitoring and oceran observation – a SiU funded research based educational program between US and Norway. Transatlantic Science Week, UC Berkeley
Konferanseforedrag

Johnsen, Geir; Sørensen, Asgeir Johan. (2011) Applied Underwater Robotics Laboratory – A new view of subsea applications. The Society for Underwater Technology (AiUT) and The Australian Hydrographic Society.
Foredrag

Johnsen, Geir. (2011) Planktonalger – fra fjernmåling til gener. NATUR 2011, Artsdatabankens konferanse om biologisk mangfold
Konferanseforedrag

Johnsen, Geir; Ardelan, Murat Van. (2011) Underwater monitoring of bio-geo-chemical objects of interest using underwater hyperspectral imagery. Transatlantic Science Week

2010

Konferanseforedrag

Dierssen, Heidi; Johnsen, Geir; Cummings, Molly; Maginnis, Tara; Holt, J.. (2010) Spectral polarized reflectance from skin preparations from four different subtropical fish species. Ocean Optics conference OOXX
Konferanseforedrag

Hovland, Erlend Kjeldsberg; Hancke, Kasper; Høkedal, Jo; Johnsen, Geir; Moline, Mark; Sakshaug, Egil. (2010) An in situ bio-optical study of Emiliania huxleyi in the Barents Sea. Oslo Science Conference (OSC)
Konferanseforedrag

Hancke, Kasper; Hovland, Erlend Kjeldsberg; Johnsen, Geir; Moline, Mark; Sakshaug, Egil. (2010) The Underwater Light Regime and cDOM across the Polar Front (Barents Sea):With relevance for the Primary Production. Oslo Science Conference (OSC)
Konferanseposter

Hovland, Erlend Kjeldsberg; Hancke, Kasper; Volent, Zsolt; Johnsen, Geir; Sakshaug, Egil. (2010) cDOM in the Barents Sea. Ocean Optics XX

2009

Konferanseforedrag

Nymark, Marianne; Valle, Kristin Collier; Brembu, Tore; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Johnsen, Geir; Bones, Atle M.. (2009) En integrert analyse av molekylær akklimatisering til sterkt lys i kiselalgen Phaeodactylum tricornutum. Algesymposium 2009
Konferanseposter

Nymark, Marianne; Valle, Kristin Collier; Hancke, Kasper; Andresen, Kjersti; Brembu, Tore; Johnsen, Geir; Bones, Atle M.. (2009) Global physiological and expression adaptation to changes in light condition in the diatom Phaeodactylum tricornutum. 45th Contact Meeting of the Norwegian Biochemical Society
Konferanseforedrag

Nymark, Marianne; Valle, Kristin Collier; Brembu, Tore; Winge, Per; Johnsen, Geir; Bones, Atle M.. (2009) Molecular mechanisms behind acclimation to high light conditions for the marine diatom Phaeodactylum tricornutum. CMB seminar series
Konferanseposter

Nymark, Marianne; Valle, Kristin Collier; Brembu, Tore; Hancke, Kasper; Winge, Per; Andresen, Kjersti; Østensen, Mari-Ann; Johnsen, Geir; Bones, Atle M.. (2009) Molecular mechanisms behind acclimation to high light conditions for the marine diatom Phaeodactylum tricornutum. Plant Biology 2009
Konferanseposter

Bones, Atle M.; Valle, Kristin Collier; Hancke, Kasper; Andresen, Kjersti; Brembu, Tore; Johnsen, Geir; Nymark, Marianne. (2009) Mining for genes, proteins, metabolites, nanoscale structures and molecular machinery of marine algae. Bioprosp2009

2008

Konferanseposter

Evertsen, Jussi; Johnsen, Geir. (2008) A window into endosymbiotic adaptation - from organelle to cell in photosynthetic phycozoans. Norske havforskeres forenings årsmøte
Konferanseposter

Hovland, Erlend Kjeldsberg; Johnsen, Geir; Moline, Mark. (2008) Combining AUV and hyperspectral imaging in coastal monitoring. Ocean Optics conference
Konferanseposter

Evertsen, Jussi; Johnsen, Geir. (2008) A window into endosymbiotic adaptation - from organelle to cell in photosynthetic phycozoans. Norske havforskeres forenings årsmøte

2007

Konferanseposter

Brembu, Tore; Valle, Kristin Collier; Størseth, T.R.; Østensen, Mari-Ann; Bjørk, Camilla; Andresen, Kjersti; Johnsen, Geir; Bones, Atle M.. (2007) The DIABOL project – mining for nanoscale structures and machinery of the diatom silica shell. Nanomat konferanse
Konferanseforedrag

Johnsen, Geir; Sakshaug, Egil. (2007) Application of in vivo fluorescence excitation spectra from different pigment-groups of phytoplankton. AquaFluo
Konferanseforedrag

Johnsen, Geir. (2007) Bruk av nye plattformer til tverrfaglig marin forskning ved NTNU. Havet og Kysten
Konferanseforedrag

Johnsen, Geir. (2007) Makroalgeforskning ved TBS-IBI. Integrate SIP konferanse
Konferanseforedrag

Johnsen, Geir. (2007) Overvåkning, kartlegging av marine ressurser ved hjelp av optikk, akustikk og telemetri. Statoil Hydro
Konferanseforedrag

Johnsen, Geir. (2007) Marine bio-optics. NTNU
Konferanseforedrag

Johnsen, Geir. (2007) Hyperspectral monitoring of ocean colour. VISTA
Konferanseforedrag

Johnsen, Geir; Volent, Zsolt; Sigernes, F.. (2007) Fine scale studies using hyper-spectral remote sensing. ESSAS meeting in marine Arctic climate
Konferanseforedrag

Johnsen, Geir. (2007) Bio-optikk til bruk i fjernmåling og in situ detektering av forskjellige biologiske komponenter i Trondheimsfjorden. Marin kystutvikling
Konferanseposter

Hancke, Torunn Beate; Hancke, Kasper; Johnsen, Geir; Sakshaug, Egil. (2007) Rate of O2 production from PAM fluorescence: Testing three bio-optical approaches against measured O2 production rate. AquaFluo Conference
Konferanseposter

Johnsen, Geir; Volent, Zsolt; Sigernes, F.; Berge, Jørgen; Hovland, Erlend Kjeldsberg; Sakshaug, Egil. (2007) Local hyperspectral imaging of ocean colour from tethered balloons in the Arctic. Arctic Frontiers Conference
Konferanseposter

Hancke, Kasper; Hancke, Torunn Beate; Olsen, Lasse Mork; Johnsen, Geir. (2007) Temperature effects on photosynthesis-light responses measured by O2 evolution, pulse amplified modulated (PAM) fluorescence and 14C assimilation. AquaFluo Conference
Konferanseposter

Johnsen, Geir; Volent, Zsolt; Sigernes, Fred; Berge, Jørgen; Hovland, Erlend Kjeldsberg; Sakshaug, Egil. (2007) Local hyperspectral imaging of ocean colour from tethered balloons in the Arctic. Arctic Frontiers

2006

Konferanseforedrag

Johnsen, Geir. (2006) Marine Biology ?. IBI meeting, NTNU
Konferanseforedrag

Johnsen, Geir. (2006) Nye tider for foto-opto-molekylo (FOM) biologi. IBI meeting, NTNU
Konferanseforedrag

Johnsen, Geir. (2006) Monitoring of phytoplankton on coastal areas. UNESCO SCOR Meeting
Konferanseposter

Hancke, Torunn Beate; Hancke, Kasper; Johnsen, Geir; Sakshaug, Egil. (2006) The use of PAM fluorescence and bio-optical characteristics to estimate oxygen production in phytoplankton. Annual meeting at the Association of Norwegian Oceanographers
Konferanseforedrag

Hancke, Kasper; Hancke, Torunn Beate; Olsen, Lasse Mork; Johnsen, Geir; Glud, Ronnie N. (2006) Temperature effects on photosynthesis: Measurements using O2-microelectrodes, Pulse Amplitude Modulated (PAM) fluorescence and 14C-incorporation techniques. Annual meeting at the Association of Norwegian Oceanographers

2005

Konferanseforedrag

Edvardsen, Bente; Eikrem, Wenche; Shalchian-Tabrizi, Kamran; Riisberg, Ingvild; Johnsen, Geir; Naustvoll, Lars; Throndsen, Jahn. (2005) Phylogeny of a new ichthyotoxic dictyochophyte forming blooms in the North Sea. Seminarserie ved CNRS Station Biologique de Roscoff
Foredrag

Johnsen, Geir. (2005) Introduction & overview of Marine Ecosystems to NFR. “Kunnskapsstatus om marine økosystem I Norge 2005”. Meeting in “Havet og kysten”
Konferanseforedrag

Johnsen, Geir. (2005) Kunnskapsstatus om marine økosystem I Norge 2005. Meeting in “Havet og kysten”
Konferanseforedrag

Johnsen, Geir. (2005) "Forskning og foto under vann” Fotoptip of GJ.www.nrk.no/programmer/TV/Newton´s hjemmside Publ. 1409 and updated 210905. Newton spesial (NRK news website)
Konferanseforedrag

Johnsen, Geir. (2005) "Forskning og foto under vann” Fotoptip of GJ.www.nrk.no/programmer/TV/Newton´s hjemmside Publ. 1409 and updated 210905. Newton spesial (NRK news website)
Konferanseforedrag

Johnsen, Geir. (2005) Evidence of global warming became so overwhelming in 2004, now the question is: What can we do about it. Vol 26, No 1 (see MEPS 303). Discover magazine (Jan issue by R. Kunzig).
Konferanseposter

Hancke, Kasper; Hancke, Torunn Beate; Olsen, Lasse Mork; Johnsen, Geir. (2005) Temperature effects on photosynthesis-light responses measured by O2-evolution, 14C-assimilation and Pulse Amplitude Modulated (PAM) fluorescence. Am. Soc. Limnol. Oceanogr. (ASLO) conference

2004

Konferanseforedrag

Edvardsen, Bente; Eikrem, Wenche; Johnsen, Geir; Shalchian-Tabrizi, Kamran; Riisberg, Ingvild; Naustvoll, Lars; Throndsen, Jahn. (2004) Phylogeny of a new ichthyotoxic dictyochophyte forming blooms in the Skagerrak. 11th International Conference on Harmful Algae
Konferanseposter

Volent, Z.; Johnsen, Geir; Sigernes, F.. (2004) Comparison study between airborne remote sensing of of ocean colour using hyperspectral imager and in situ measurements of optical properties in surface waters in an Arctic fjord, Svalbard, May 2004. Poster
Konferanseforedrag

Johnsen, Geir; Hancke, Torunn Beate. (2004) SISCAL dissemination evaluation. Foredrag
Konferanseposter

Salvesen, Ingrid; Brakstad, I.; Givskov, M.; Johnsen, Geir; Skindersø, M.; Størseth, Trond. (2004) Antibacterial activity in crude extracts of marine macroalgae. Poster
Konferanseposter

Berge, J.; Johnsen, Geir; Nilsen, F.; Gulliksen, B.. (2004) Discovery of blue mussels (Mytilus edulis) in Svalbard - indication of temperature increase in the Arctic marine environment. Poster
Konferanseforedrag

Johnsen, Geir; Evertsen, Jussi. (2004) Photosynthetic Nudibranchs and Sacoglossans. Foredrag/poster
Konferanseforedrag

Johnsen, Geir; Hancke, Torunn Beate. (2004) SISCAL processor evaluation. Fordrag
Konferanseforedrag

Johnsen, Geir. (2004) Presentation of SISCAL and the use of remote sensing. Foredrag
Konferanseforedrag

Johnsen, Geir; Evertsen, Jussi. (2004) Photosynthetic Opisthobranchs. Foredrag
Konferanseforedrag

Forbord, Silje; Johnsen, Geir. (2004) Marine bio-prospecteering of marine macroalgae. Foredrag
Konferanseforedrag

Johnsen, Geir. (2004) Light utilzation in 13 different pigments groups of phytoplankton. Foredrag
Konferanseforedrag

Edvardsen, Bente; Eikrem, Wenche; Johnsen, Geir; Naustvoll, L.; Riisberg, I.; Shalchian-Tabrizi, K.; Trondsen, Jahn. (2004) Verruca fascima gen. et. sp. nov. (Dictyochophyceae, Heterokontophyta) a bloom forming ichthyotoxic flagellate isolated from Skagerrak, Norway. Foredrag
Konferanseposter

Bredholt, Harald; Fjærvik, E.; Johnsen, Geir; Johansen, G.; Sletta, Håvard; Ellingsen, Trond Erling; Zotchev, Sergey. (2004) Isolation and characterization of actinomycete bacteria from sediments in the Trondheimsfjord, Norway. Genetics and Molecular Biology of Industrial Microorganisms conference
Konferanseposter

Bredholt, Harald; Fjærvik, Espen; Johnsen, Geir; Hancke, Torunn Beate. (2004) Isolation and characterization of actinomycete bacteria from sediments in the Trondheimsfjord, Norway. GMBIM/BMP
Konferanseforedrag

Olsen, Lasse Mork; Øzturk, Murat; Sakshaug, Egil; Vadstein, Olav; Sandaa, Ruth Anne; Johnsen, Geir. (2004) Interactions between metabolism, geochemistry and bacterial diversity in cultures of the marine dinoflagellate Prorocentrum minimum. ASLO møte
Konferanseforedrag

Bredholt, Harald; Fjærvik, E.; Hakvåg, Sigrid; Sletta, Håvard; Johnsen, Geir; Ellingsen, Trond Erling; Zotchev, Sergey. (2004) Mining for antibiotic-producing bacteria in the Trondheim fjord. BIOPROS 2004

2003

Konferanseposter

Forbord, Silje; Valle, Kristin Collier; Hilstad, Kari; Evertsen, Jussi; Johnsen, Geir. (2003) Annual variation of pigments in marine red-, brown- and green macroalgae. Norske havforskeres forening, årsmøtet
Konferanseposter

Evertsen, Jussi; Johnsen, Geir. (2003) Opisthobranchs with solar panels. Norske havforskeres forening, årsmøtet
Konferanseposter

Hilstad, Kari; Evertsen, Jussi; Forbord, Silje; Valle, Kristin Collier; Johnsen, Geir. (2003) Annual variation in bio-optical characteristics in marine red-, brown-, and green macro algae. Norske havforskeres forening, årsmøtet
Konferanseposter

Valle, Kristin Collier; Forbord, Silje; Hilstad, Kari; Evertsen, Jussi; Johnsen, Geir. (2003) Detectation of annual variation in red-, brown- and green macroalgae using in situ video technique and fluorescence microscopy. Norske havforskeres forening, årsmøtet
Konferanseposter

Volent, Z.; Johnsen, Geir. (2003) Presentation of an optical sensor for in situ detection of phytoplankton, inorganic particles and yellow substance. Norske Havforskers Forenings årsmøte
Konferanseposter

Johnsen, Geir. (2003) Bio-optical characterization in 10 major phytoplankton classes. Norske Havforskers Forenings årsmøte
Konferanseforedrag

Johansen, Torunn Beate; Johnsen, Geir. (2003) SISCAL prototype evaluation. SISCAL Second Annual Meeting

2002

Konferanseposter

Evertsen, Jussi; Johansen, Torunn Beate; Johnsen, Geir. (2002) MODTEQ Module 2 - bio-optical methods. Model based development of advanced marine equipment. Norske Havforskeres Forenings årsmøte
Konferanseposter

Salvesen, Ingrid; Størseth, Trond; Johnsen, Geir; Brakstad, O.G.. (2002) Bakteriehemmenede forbindelser i marine alger: Utvikling av miljøvennlige strategier for å kontrollere virulens og begroing. Ikke opplyst
Konferanseposter

Fell, Frank; Herut, Barak; Johansen, Torunn Beate; Johnsen, Geir; Brozek, Morten; Hanssen, Frank. (2002) SISCAL: internet-based delivery of near-real-time data products on coastal areas and lakes from satellite imagery. SPIE
Konferanseposter

Størseth, Trond; Reitan, Kjell Inge; Salvesen, Ingrid; Skjermo, Jorunn; Rainuzzo, J.; Johnsen, Geir; Partali, Vassilia. (2002) Immunostimulants and Antimicrobial Compounds from algae, Isolation and Characterization. Marin bioprospektering
Konferanseposter

Salvesen, Ingrid; Johnsen, Geir; Rainuzzo, J.; Reitan, Kjell Inge; Skjermo, Jorunn; Størseth, Trond. (2002) Immunstimulerende og antibakterielle forbindelser fra marine alger. Marin bioprospektering. Marin bioprospektering
Konferanseposter

Johansen, Torunn Beate; Evertsen, Jussi; Johnsen, Geir. (2002) SISCAL - satellite-based information system on coastal areas and lakes. Norske havforskeres forening, årsmøtet
Konferanseforedrag

Fell, Frank; Herut, Barak; Johansen, Torunn Beate; Johnsen, Geir; Brozek, Morten; Hanssen, Frank. (2002) SISCAL project: establishing an internet-based delivery of near-real-time data products on coastal areas and lakes from satellite imagery. SPIE 2002
Konferanseforedrag

Børsheim, Knut Yngve; Kirkvold, Ståle; Johansen, Torunn Beate; Johnsen, Geir. (2002) Measurement of phytoplankton mortality as a tool to estimate turnover of phytoplankton biomass. Phytoplankton Productivity. An Appreciation of 50 years of the study of oceans and lakes
Konferanseforedrag

Johnsen, Geir. (2002) End user requirements in SISCAL (EU Romete sensing project). SISCAL meeting
Foredrag

Johnsen, Geir. (2002) Queen Maud and myself. Norwegian Antarctic Research Expedition jan-mar 2001. Primary production under the sea ice

2001

Konferanseforedrag

Ødegaard, Øyvind Tangen; Sortland, Bjørn; Ellingsen, Ingrid Helene; Slagstad, Dag; Johnsen, Geir; Sakshaug, Egil. (2001) An Interdisciplinary Marine Research Programme: How to promote generative interaction between marine scientists, modellers and engineers. OCEANS, 2001. MTS/IEEE Conference and Exhibition

2000

Konferanseforedrag

Johnsen, Geir. (2000) Bio-optics as a tool to detect physiological status in toxic algae. Conference in EC MAST III prosject.
Konferanseforedrag

Johnsen, Geir; Legrand, C; Chauton, Matilde Skogen; Eigeland, E; Sakshaug, Egil. (2000) The use of a DIVING-PAM for detection of irradiance, biomass and photosystem II fluorescene yield in harmful algal bloom experiments: Discussion of methodological aspects. HAB 2000
Konferanseforedrag

Legrand, C; Johnsen, Geir; Graneli, E; Sakshaug, Egil. (2000) Effect of polyamines on growth and toxicity of Chrysochromulina leadbeateri and Prymnesium patellifreum (Haptophytes). HAB 2000
Konferanseforedrag

Legrand, C; Johnsen, Geir; Graneli, E; Sakshaug, Egil. (2000) Effect of polyamines on growth and toxicity of Chrysochromulina leadbeateri, Haptophytae. Proceedings of the 9th International conference on Harmful Algal Blooms.
Konferanseforedrag

Johnsen, Geir. (2000) Bio-optical instruments for use in marine water and plankton. SINTEF seminarseries in bio-optics held at auditorium E5-101 Realfagsbygget NTNU, Gløshaugen.
Konferanseforedrag

Johnsen, Geir. (2000) Why bio-optics in marine biology. 2nd NTNU seminarseries in bio-optic held at the auditorium Trondhjem Biological Station.
Foredrag

Mork, Jarle; Johnsen, Geir; Tokle, Nils Egil; Evensen, Jussi; Andresen, Kjersti. (2000) Trondhjem Biologiske Stasjon. Poster presentasjon. Trøndelagsmessa 2000
Konferanseposter

Legrand, C; Johnsen, Geir; Graneli, E; Sakshaug, Egil. (2000) Effect of polyamines on growth and toxicity of Chrysochromulina leadbeateri and Prymnesium patelliferum (Haptophytae). 9th International conference on Harful Algal Blooms.
Konferanseforedrag

Chauton, Matilde Skogen; Johnsen, Geir; Legrand, C; Sakshaug, Egil; Granëli, E. (2000) Development of a pontential harmful algal bloom in a mesocosm experiment monitored through pigment analysis and bio-optical measurements. HAB 2000
Konferanseforedrag

Granëli, E; Legrand, C; Carlsson, P; Maestrini, SY; Johnsen, Geir; Hummert, C; Pallon, J; Luckas, B; Sakshaug, Egil. (2000) Nitrogen and phosphorus deficiency favours the dominance and toxin content of harmful species in summer Baltic Sea phytoplankton. HAB 2000
Konferanseposter

Graneli, E; Legrand, C; Carlsson, P; Maestrini, S.Y; Hummert, C; Reichelt, M; Johnsen, Geir; Pallon, J; Luckas, B; Sakshaug, Egil. (2000) Nitrogen and phosphorus deficiency favours the dominance and toxin content of harmful species in summer Baltic Sea phytoplankton. 9th International conference on Harmful Algal Blooms.
Konferanseposter

Johnsen, Geir; Legrand, C; Graneli, C; Sakshaug, Egil. (2000) The use of a DIVING-PAM for detection of irradiance, biomass and photosystem II fluorescence yields in harmful algal bloom experiments: Discussion of methodological aspects. 9th International conference on Harmful Algal Blooms.
Konferanseposter

Tilstone, G; Johnsen, Geir; Chauton, Matilde Skogen; Johansen, T; Figueiras, F.G. (2000) Temporal evolution of photosynthetic parameters and primary prodution during a bloom of an ichthytoxic prymnesiophyte under different N/P ratios. 9th International conference on Harmful Algal Blooms.
Konferanseposter

Chauton, Matilde Skogen; Johnsen, Geir; Legrand, C; Graneli, E; Sakshaug, Egil. (2000) Development of a potential harmful algal bloom in mesocosm experiment monitored through pigment analysis and bio-optical measurements. 9th International conference on Harmful Algal Blooms.
Konferanseforedrag

Wägele, H; Johnsen, Geir. (2000) New result on histology and photosynthetic performance of solar-powered¨ opisthobranchs (Mollusca, Gastropoda, Opisthobranchia) constaining symbiotic chloroplasts or zooxanthellae. -
Konferanseforedrag

Johnsen, Geir. (2000) Inhibition of toxin production in cultures. Conference in EC MART III prosject.
Konferanseforedrag

Johnsen, Geir. (2000) Fish killing species. Conference in EC MAST III project ¨NUTOX¨
Konferanseforedrag

Johnsen, Geir. (2000) PSP producer Alexandrium tamarense II. Conferrnce in EC MAST III project.
Konferanseforedrag

Johnsen, Geir. (2000) Inhibition of toxin production in natural communities. Conference in EC MAST III ¨NUTOX¨

1999

Konferanseforedrag

Legrand, C; Johnsen, Geir; Hummert, C; Graneli, E. (1999) Variation in toxin production in two strains of Alexandrium tamarense: Effects of nitrogen and phosphorus replete vs. limited growth conditions. ASLO winter meeting.
Konferanseforedrag

Graneli, E; Carlsson, P; Legrand, C; Johnsen, Geir; Luckas, B; Maestrini, S. Y; Reichelt, M. (1999) Structuration of marine phytoplankton communities subjected to different levels of N, P and Si limitation in a mesocosm experiment. ASLO winter meeting.

1998

Konferanseforedrag

Chauton, Matilde Skogen; Johnsen, Geir; Sakshaug, Egil. (1998) In vivo fluorescence exitation spectra of phytoplankton. CANIGO 2nd general meeting.
Konferanseforedrag

Johnsen, Geir; Sakshaug, Egil. (1998) Monitoring of Harmful Algal Blooms using bio-optical methods. International Symposium and workshop on harmful algal blooms in the Benguela current region and other upwelling ecosystems. Phagotrophy and toxicity in photosynthetic Prymnesium patellifreum (Haptophyte).

1997

Konferanseforedrag

Johnsen, Geir; Sakshaug, Egil. (1997) Chlorophyll c3-containing prymnesiophytes and dinoglagellates: a potentially harmful phytoplankton group. VIII International Conference on Harmful Algae,

1996

Konferanseforedrag

Egeland, E. S; Johnsen, Geir; Jensen, S Liaaen-. (1996) Variable carotenoid composition in a prasinophycean phytoplankton acclimated to three different irradiances. 11th International Symposium on carotenoids,

1994

Konferanseforedrag

Johnsen, Geir; Sakshaug, Egil. (1994) Pigment composition and photoadaptive pigment variation in three toxic marine dinoflagellate species. Ocean Science Meeting (ASGU/ASLO).

1993

Konferanseforedrag

Johnsen, Geir; Nelson, N. B; Jovine, R. V. M; Prezelin, B. B. (1993) Chromoprotein- and pigment dependent modeling of spectral light absorption in two dinoflagellates, Prorocentrum minimum and Heterocapsa pygmaea. Optical properties and quantum yields of aquatic photosynthetic systems. Binational Scientific Fundation Workshop.

1992

Konferanseforedrag

Volent, Z; Johnsen, Geir. (1992) Presentation of an optical algae sensor "Optisens" designed for Eulerian measurements from a moored buoy. In: Autonomous bio-optical ocean observin systems scientific symposium (ABOOS). [Mangler data]
Konferanseforedrag

Johnsen, Geir; Samset, O; Volent, Z. (1992) Optical characteristics of phytoplankton in relation to remote sensing. In: Autonomous boi-optical ocean observing systems scientific symposium (AB. [Mangler data]

1990

Konferanseforedrag

Johnsen, Geir; Gilstad, M; Sakshaug, Egil. (1990) Diurnal variations in light absorption spectra, fluorescence excitation spectra and pigment composition in the marine diatom skeletonema costatum. NATO/ASI Individual cell & particle analysis in oceanography. Aquafredda di Maratea,
Konferanseforedrag

Gilstad, M; Johnsen, Geir; Sakshaug, Egil. (1990) Diurnal varations in cell chemistry, photosynthetic parameters and respiration in the marine diatom skeletonema costatum. In: NATO/ASI Individual cell & particle analysis in oceanography. Aquafredda di Maratea.

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