Three new ARCTOS PhDs – Snorre Flo, Cheshtaa Chitkara and Antonia Klöcker

We have three PhD candidates who have defended their PhD theses in the last weeks, take a look at their summaries below:

Five people standing holding glasses of champagne, Dr. Flo in the middle
From left: Committee leader Associate Professor Christian Selbach (UiT), supervisor Anna Vader, Dr. Snorre Flo, second opponent Dr. Jens C. Nejstgaard (Leibniz Institute of Freshwater Ecology and Inland Fisheries, Germany), first opponent Professor Monika Quinoes Winder (Stockholm University, Sweden)

Dr. Snorre Flo successfully defended his PhD thesis on May 26, 2025 at UNIS in Longyearbyen. The title of his thesis was: “On the appetites of small copepods and nematodes in the Arctic Barents Sea and Nansen Basin: In situ trophic interactions revealed by brute force prey metabarcoding”, which can be found here.

His supervisory team has been: Associate professor Anna Vader (UNIS) and Professors Camilla Svensen, Bodil A. Bluhm and Kim Præbel (all UiT).

Dr. Flo’s thesis consists of three papers:

Paper I: Flo, S., Vader, A. & Præbel, K. (2024). Brute force prey metabarcoding to explore the diets of small invertebrates. Ecology and Evolution, 14(5), e11369. https://doi.org/10.1002/ece3.11369

Paper II: Flo, S., Svensen, C., Præbel, K., Bluhm, B.A. & Vader, A. (2024). Dietary plasticity in small Arctic copepods as revealed with prey metabarcoding. Journal of Plankton Research, 46(5), 514. https://doi.org/10.1093/plankt/fbae042

Paper III: Flo, S., Bluhm, B.A., Svensen, C., Præbel, K. & Vader, A. Eukaryote food acquisition in Arctic marine nematodes across seasons and shelf-to-basin gradients. (Manuscript).

Five people standing and holding glasses of champagne, Dr. Chitkara in the middle.
From left: Supervisors Tove M. Gabrielsen (UiA, UNIS) and Anna Vader (UNIS), Dr. Cheshtaa Chitkara, committee leader professor Ane Timenes Laugen (UiA), first opponent professor Daniel Vaulot (UiO). Second opponent Dr. Matthias Wietz (AWI, Germany) participated digitally.

Dr. Cheshtaa Chitkara successfully defended her PhD thesis on May 28, 2025 at UNIS in Longyearbyen. The title of her thesis was: “Arctic marine microbial eukaryotes – Spatiotemporal drivers of community structure and ecological impacts of Atlantification”, which can be found here.

Her supervisors have been Associate Professor Anna Vader (UNIS) and Professor Tove M. Gabrielsen (UiA/UNIS).

Dr. Chitkara’s thesis consists of three papers:

Paper I: Chitkara, C., Juul-Pedersen, T., Krawczyk, D., Søreide, J., Vader, A., Gradinger, R. R., HS Winding, M. & Vonnahme, T. R. (2024). Seasonality in phytoplankton communities and production in three Arctic fjords across a climate gradient. Progress in Oceanography, 227, 103317. https://doi.org/10.1016/j.pocean.2024.103317

Paper II: Chitkara, C., Gabrielsen, T.M., Vonnahme, T., Skogseth, R., Krabberød, A. K., Petelenz, E. A., Larsen, A., Vader, A. ( Unpublished manuscript). Tracking the effects of Atlantification on microbial eukaryotes in an Arctic marine time series, IsA

Paper III: Chitkara, C., Gabrielsen T. M., Skogseth, R., Descôteaux, R. & Vader A. (Unpublished manuscript). Seasonality of planktonic microbial eukaryotic communities in Arctic versus Atlantic Spitsbergen fjords.

Eight people standing, Dr. Klöcker in the middle holding flowers.
From left to right: Eva B. Thorstad (2. Opponent), Dag O. Hessen (administrator), Yannis Papastamatiou (1. Opponent), Alexander Eiler (Chair), Claudia Junge (Supervisor), Mikko Vihtakari (Supervisor), Øystein Langangen (Supervisor).

Dr. Antonia Klöcker has successfully defended her PhD thesis on June 2, 2025 at UiO in Oslo. The title of her thesis was: “On the move: The movement ecology of sharks in high-latitude waters and Beyond”, which can be found here.

Her supervisory team has been: Researcher Claudia Junge (IMR), Associate Professor Øystein Langangen (UiO), Researcher Mikko Vihtakari (IMR) and Principal Researcher Nuno Queiroz (University of Porto).

Dr. Klöcker’s thesis consists of four papers:

Paper I: Klöcker et al. Seasonal habitat use and diel vertical migration in female spurdog in Nordic waters. Movement Ecology, 2024, 12(1):62. https://doi.org/10.1186/s40462-024-00498-2

Paper II: Klöcker, C. A., Schlindwein, A., Arostegui, M. C., Bruvold, I. M., Wernström, J. V., Martin-Armas, M., Sims, D. W., Straube, N., Altenburger, A., & Junge, C. (2025). Giants in the cold: Morphological evidence for vascular heat retention in the viscera but not the skeletal muscle of the basking shark (Cetorhinus maximus). Journal of Fish Biology, 1–20. https://doi.org/10.1111/jfb.70052

Paper III: Klöcker, C.A., Bjelland, O., Ferter, K. et al. Basking sharks of the Arctic Circle: year-long, high-resolution tracking data reveal wide thermal range and prey-driven vertical movements across habitats. Anim Biotelemetry 13, 15 (2025). https://doi.org/10.1186/s40317-025-00407-3

Paper IV: Klöcker et al. (Manuscript). Away from the edge and back again: Seasonal residency and large-scale return migrations of basking Sharks in high-latitude environments.

Congratulations to Dr. Flo, Dr. Chitkara and Dr. Klöcker on their huge successes and wish them the best in their future careers!