Arctic and Subarctic marine heatwaves and their ecological impacts

Abstract

In this review paper, we searched and analyze the literature to understand the trends, mechanisms and ecological impacts of Arctic marine heatwaves (MHWs), prolonged period of abnormally high sea temperatures. MHWs are predicted to increase in the Arctic and Subarctic regions, and they can pose unique challenges to these high-latitude marine ecosystems. The accelerated warming and sea ice loss in these areas threaten species that are adapted to cold conditions. We show that MHWs in the Arctic and Subarctic seas are becoming increasingly prevalent and have significant ecological impacts across various organism groups. This was especially documented in the Arctic marginal seas such as the Bering and Barents seas. These impacts are particularly severe in areas experiencing sea ice retreat. Arctic species, with their cold- and narrow thermal preferences are especially vulnerable to MHWs, whereas boreal species could potentially benefits from these heat events. The review also emphasizes the limited evidence of MHW impacts on some taxa, such as sessile foundation species like kelp and seagrasses, pointing to gaps in current research.

The review’s insights into the ecological impacts of MHWs demonstrate the urgency of developing conservation strategies and adaptive management practices to protect biodiversity in European marine regions, which are crucial for maintaining ecological balance and supporting socio-ecological systems.