It took two weeks of intensive effort: traveling to the site, establishing the camp, conducting fieldwork on the water, and returning to the laboratory for analysis. The experts arrived at Kongsfjord in Ny-Ålesund, their primary research area, under overcast, rainy skies in early August. This location is ideal for studying the effects of climate change, arguably better than almost anywhere else on the planet. In the Arctic, ocean temperatures are increasing at twice the rate of the global average. The YESSS project aims to explore the seasonal impacts of this warming on the life cycles, feeding habits, and overwintering of various flora and fauna, particularly during the darker months—about which we currently know very little.

At the AWIPEV research station in Ny-Ålesund, the team has established comprehensive research facilities. Equipment and materials were transported to Svalbard using airplanes and the AWI research ship, Heincke. With the setup complete, the standard data collection process has begun: a small team goes out on the Kongsfjord by boat every week, collecting water samples at depths ranging from five to 300 meters at the same designated locations. Concurrently, they gather data on variables such as temperature and light penetration at different depths. These water samples and the organisms they contain will be analyzed in the station’s laboratory.

The research station is equipped with aquariums and tanks designed to replicate projected climate changes.

As Dr. Clara Hoppe, a biologist at AWI and Principal Investigator of YESSS, explains: “In parallel experiments with the current water temperature and water that is three and six degrees warmer, we’re investigating how marine organisms react to the higher temperatures.” She adds, “Rising temperatures are a stress factor and can lead to higher resource consumption – with consequences for the entire ecosystem.”

These experiments on temperature sensitivity focus on key components of the Arctic food web: phytoplankton, which are microscopic single-celled organisms that form the base of the food chain; macroalgae (like seaweed), molluscs (such as mussels), echinoderms (like sea urchins), and fish (including Arctic cod).

Studying arctic cod: Uncovering climate impact on a key species

Over recent weeks, the research team has been capturing specimens of Arctic cod, a key model organism, using the Heincke.

“In early August, we sailed from Bremerhaven on a direct course to Svalbard,” recounts Dr. Felix Mark, a marine ecophysiologist at AWI and the leader of the expedition. “Along the way, we collected some samples of zooplankton and water samples.”

Upon reaching the Kongsfjord in northwest Svalbard, the team began catching Arctic cod, which they will study both in Svalbard and later in Bremerhaven over the coming months.

The team transported approximately 500 fish to the German-French AWIPEV station using a specially designed aquarium container on board the Heincke. At the station, researchers will employ sensors to monitor and record various parameters over several months, including the fishes‘ heart rates, metabolic rates, energy consumption, and growth in both weight and length.

Arctic cod is currently the most common fish species in the Arctic Ocean, but its future is uncertain. Human activities and climate change are altering its habitat so drastically that every stage of its life—from spawning to daily survival—is affected. These changes, in turn, have cascading effects throughout the ecosystem, as Arctic cod is a crucial food source for Arctic marine mammals and indigenous Inuit communities. However, much of our understanding of these processes comes from studies conducted in the Arctic’s spring and summer months.

All participating research institutions and universities will have access to the original samples of various model organisms collected from Kongsfjord, as well as the datasets produced in the lab. Using data on resilience to higher temperatures and other overwintering strategies, the experts will create a new ecosystem model that identifies potential “winners” and “losers” in the context of climate change, as well as temperature tipping points for the ecosystem in different seasons.

With the setup and initial research activities for YESSS now complete in Ny-Ålesund, four PhD candidates will remain at the station, collecting samples and preparing analyses on a weekly basis. Every six weeks, two of them will be rotated out and replaced by other team members. These young scientists are embarking on an exciting challenge: surviving the long, dark polar winter in the Kongsfjord. Throughout the year, updates on their experiences and contributions to climate research will be shared regularly on the YESSS social media channels.