Exciting research in progress: Heatwaves in the seas around Svalbard are being investigated by a PhD candidate

The Nansen Center has established the PRIMA research project to study the development of marine heatwaves in the High North and their consequences. Marianne Williams-Kerslake has been employed in a PhD position at The Nansen Center to investigate these issues further, including how marine heatwaves can be predicted. Marianne is from the UK and completed her MSc in Marine Biology and Oceanography at the University of Southampton.

When the sea surface in an area is much warmer than normal over a long period of time, we talk about a marine heatwave. A typical criterion is that the extreme temperatures should last for 5 days, but these episodes can also last for several weeks, or months. The Arctic Ocean and surrounding seas are particularly vulnerable to this phenomenon, and the seas around Svalbard have experienced several such heatwaves in recent years. Marianne has identified these waters as a key area for her research. She went to Svalbard for a research stay in the autumn of 2024 to find out how she could best identify the triggers that lead to marine heatwaves.

She started the process by validating and comparing in-situ data from instruments in the seas around Svalbard with data from a dynamical reanalysis that covers the area from the North Atlantic Ocean to the Arctic Ocean. The Nansen Center produces and constantly updates this reanalysis through the TOPAZ system, which is also used by Copernicus Marine Service. The comparison Marianne has made shows that the reanalysis represents well the actual variability in the seas west of Svalbard. This provides an exciting opportunity to gain insight into the spatial and vertical extent of marine heatwaves in this region.

Marianne is soon planning an analysis selected ocean regions to investigate the conditions that must be present for marine heatwaves to occur. She will build on this information to find out if and how these events can be predicted in advance.

In the final part of her PhD project, she will link her work to marine biology and investigate how the organisms at the bottom of the food pyramid – specifically phytoplankton, which are consumed by larger organisms, which in turn will be consumed by higher-level consumers – are affected by marine heatwaves in the Arctic seas.

The Nansen Center looks forward to exciting research results from the work of Marianne Williams-Kerslake!

Key researchers: Marianne Williams-Kerslake, Helene R. Langehaug, Annette Samuelsen, Noel Keenlyside

Marine heatwaves

Marine heatwaves can occur anywhere in the world’s oceans and at any time, as long as conditions favour a sharp rise in temperature. In recent decades, marine heatwaves have become both more frequent and more intense, which is linked to global warming. This trend is expected to continue in the future.

Read more about marine heatwaves, how they can be predicted and their consequences here.

About Svalbard

Svalbard is a Norwegian archipelago located in the Arctic, between mainland Norway and the North Pole. The islands are surrounded by several seas. The Greenland Sea lies to the west, the Arctic Ocean to the north and the Barents Sea to the east.  These seas have sea ice and are important for both wildlife and research. South of Svalbard lies the Norwegian Sea. Here dominates the Norwegian Atlantic Current and the Norwegian Sea is sea-ice free.

The PRIMA research project

The PRIMA project at the Nansen Center is dedicated to research on the forecasting of marine heatwaves in northern seas. A group of researchers with different expertise are working together to create the best possible picture of what characterises marine heatwaves in the region, what it takes to predict them, and what impact they have on biological and biogeochemical conditions in the ocean.