World's Best Scientists 2026 revealed!

D-Index & Metrics

Environmental Sciences

D-Index
55
Citations
9496
World Ranking
3903
National Ranking
44

Biology and Biochemistry

D-Index
55
Citations
9369
World Ranking
15206
National Ranking
76

Overview

Geir Johnsen is affiliated with the Norwegian University of Science and Technology in Norway. Their research spans Environmental Science and Earth and Planetary Sciences, with a significant focus on Oceanography and Ecology among related subfields. Their scientific work addresses various aspects of marine environments, including long-term ecological changes and pollution effects.

The scientist's main fields of study include:

  • Environmental Science
  • Earth and Planetary Sciences

Their work delves into several subfields:

  • Oceanography
  • Ecology
  • Global and Planetary Change
  • Pollution
  • Ecology, Evolution, Behavior and Systematics

Johnsen's research topics cover diverse marine and ecological themes such as:

  • Isotope Analysis in Ecology
  • Marine and coastal ecosystems
  • Marine animal studies overview
  • Marine and coastal plant biology
  • Marine Biology and Ecology Research
  • Cephalopods and Marine Biology
  • Marine and fisheries research

The scientist has published multiple papers capturing advancements and observations in marine science and remote sensing technologies. Selected recent papers include:

  • "Hyperspectral imaging as an emerging tool to analyze microplastics: A systematic review and recommendations for future development," 2021, Microplastics and Nanoplastics
  • "Artificial light during the polar night disrupts Arctic fish and zooplankton behaviour down to 200 m depth," 2020, Communications Biology
  • "Mapping the Historical Shipwreck Figaro in the High Arctic Using Underwater Sensor-Carrying Robots," 2020, Remote Sensing
  • "HYPSO-1 CubeSat: First Images and In-Orbit Characterization," 2023, Remote Sensing
  • "Still Arctic?-The changing Barents Sea," 2023, Elementa Science of the Anthropocene

Johnsen's frequent co-authors include:

  • Jørgen Berge
  • Glaucia M. Fragoso
  • David McKee
  • Jonathan H. Cohen
  • Tor Arne Johansen

The scientist has also contributed to academic book publications. Notably, they authored a book titled POLAR NIGHT Marine Ecology, published in 2020 by Springer International Publishing.

Johnsen's research output appears in specific publication venues with multiple contributions, including:

  • Zenodo (CERN European Organization for Nuclear Research)
  • Applied Optics
  • Remote Sensing
  • Scientific Reports
  • Frontiers in Marine Science

Best Publications

  • Phytoplankton pigments : characterization, chemotaxonomy and applications in oceanography

    Suzanne Roy;Carole A. Llewellyn;Einar Skarstad Egeland;Geir Johnsen

  • Ocean temperature oscillations enable reappearance of blue mussels Mytilus edulis in Svalbard after a 1000 year absence

    Jørgen Berge;Geir Johnsen;Frank Nilsen;Bjørn Gulliksen

  • Leads in Arctic pack ice enable early phytoplankton blooms below snow-covered sea ice

    Philipp Assmy;Mar Fernández-Méndez;Pedro Duarte;Amelie Meyer

  • An Integrated Analysis of Molecular Acclimation to High Light in the Marine Diatom Phaeodactylum tricornutum

    Marianne Nymark;Kristin C. Valle;Tore Brembu;Kasper Hancke

  • Detection of harmful algal blooms using photopigments and absorption signatures: A case study of the Florida red tide dinoflagellate, Gymnodinium breve

    David F. Millie;Oscar M. Schofield;Gary J. Kirkpatrick;Geir Johnsen

  • Actinomycetes from sediments in the Trondheim fjord, Norway: diversity and biological activity.

    Harald Bredholt;Espen Fjærvik;Geir Johnsen;Sergey B. Zotchev

  • The Storegga tsunami along the Norwegian coast, its age and run up

    Stein Bondevik;John Inge Svendsen;Geir Johnsen;Jan Mangerud

  • 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 fluorometry1

    Geir Johnsen;Egil Sakshaug

  • The effect of food limitation on vertical migration in Daphnia longispina

    Geir Helge Johnsen;Per Johan Jakobsen

  • In the dark: A review of ecosystem processes during the Arctic polar night

    Jørgen Berge;Paul E. Renaud;Gerald Darnis;Finlo Cottier

  • Diel vertical migration of Arctic zooplankton during the polar night

    Jørgen Berge;Finlo Cottier;Øystein Varpe

  • Unexpected Levels of Biological Activity during the Polar Night Offer New Perspectives on a Warming Arctic.

    Jørgen Berge;Malin Daase;Paul E. Renaud;William G. Ambrose

  • Bio‐optical characteristics and photoadaptive responses in the toxic and bloom‐forming dinoflagellates gyrodinium aureolum, gymnodinium galatheanum, and two strains of prorocentrum minimum¹

    Geir Johnsen;Egil Sakshaug

  • Molecular and photosynthetic responses to prolonged darkness and subsequent acclimation to re-illumination in the diatom Phaeodactylum tricornutum.

    Marianne Nymark;Kristin Collier Valle;Kasper Hancke;Per Winge

  • In vivo absorption characteristics in 10 classes of bloom-forming phytoplankton: taxonomic characteristics and responses to photoadaptation by means of discriminant and HPLC analysis

    Unknown

  • Using absorbance and fluorescence spectra to discriminate microalgae

    David F. Millie;Oscar M. E. Schofield;Gary J. Kirkpatrick;Geir Johnsen

  • Pigments and photoacclimation processes

    Christophe Brunet;Geir Johnsen;Johann Lavaud;Suzanne Roy

  • THE SIGNIFICANCE OF INTRACELLULAR SELF‐SHADING ON THE BIOOPTICAL PROPERTIES OF BROWN, RED, AND GREEN MACROALGAE1

    Joe Grzymski;Geir Johnsen;Egil Sakshaug

  • Modeling of light-dependent algal photosynthesis and growth: experiments with the Barents sea diatoms Thalassiosira nordenskioldii and Chaetoceros furcellatus

    Egil Sakshaug;Geir Johnsen;Kjersti Andresen;Maria Vernet

  • Photoacclimation in phytoplankton: implications for biomass estimates, pigment functionality and chemotaxonomy

    F. Rodríguez;M. Chauton;G. Johnsen;K. Andresen

  • Phytoplankton Pigments: Aids for practical laboratory work

    Suzanne Roy;Carole A. Llewellyn;Einar Skarstad Egeland;Geir Johnsen

Frequent Co-Authors

Jørgen Berge
Jørgen Berge University of Tromsø - The Arctic University of Norway
Egil Sakshaug
Egil Sakshaug Norwegian University of Science and Technology
Mark A. Moline
Mark A. Moline University of Delaware
Suzanne Roy
Suzanne Roy Université du Québec à Rimouski
Finlo Cottier
Finlo Cottier Scottish Association For Marine Science
Asgeir J. Sørensen
Asgeir J. Sørensen Norwegian University of Science and Technology
Stig Falk-Petersen
Stig Falk-Petersen University of Tromsø - The Arctic University of Norway
Øystein Varpe
Øystein Varpe University of Bergen
Atle M. Bones
Atle M. Bones Norwegian University of Science and Technology

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