Biodiversity changes in Arctic coastal ecosystems under borealization

This study combines three decades of abundance data across multiple animal groups and regions in the European Arctic and Greenland to assess biodiversity change in Arctic coastal communities. The results support widespread borealization, with Arctic endemic species generally declining while boreal species increase, alongside an average rise in biodiversity that may nevertheless mask uncertain long-term consequences for Arctic ecosystem functioning and services.

Predicting potential Arctic kelp distribution and lower-depth biomass from seafloor irradiance

This paper develops a framework for estimating potential Arctic kelp distribution and lower-depth biomass from seafloor irradiance. Using fjord-specific empirical relationships, it links standing stock estimates to light availability and its drivers, providing a baseline for tracking how changing coastal light environments may alter Arctic kelp biomass under ongoing environmental change.

Summer primary production of Arctic kelp communities is more affected by duration than magnitude of simulated marine heatwaves

This study examines how mixed Arctic kelp communities respond to simulated marine heatwaves that vary in duration and magnitude. A mesocosm experiment showed that prolonged heatwave exposure reduced accumulated net community production more strongly than shorter, more intense events, highlighting the importance of duration when assessing marine heatwave impacts on fjord kelp ecosystems.

Productivity of mixed kelp communities in an Arctic fjord exhibit tolerance to a future climate

This study evaluates how mixed kelp communities in an Arctic fjord respond to combined future stressors associated with climate change, including warming, freshening, and reduced light. Using a two-month mesocosm experiment, it shows that summer net productivity remains comparatively tolerant across treatment conditions, while light availability exerts the strongest control on net community production.

Marine heatwaves drive recurrent mass mortalities in the Mediterranean Sea

Climate change is causing an increase in the frequency and intensity of marine heatwaves (MHWs) and mass mortality events (MMEs) of marine organisms are one of their main ecological impacts. Here, we show that during the 2015–2019 period, the Mediterranean Sea has experienced exceptional thermal conditions resulting in the onset of five consecutive years of widespread MMEs across the basin. These MMEs affected thousands of kilometers of coastline from the surface to 45 m, across a range of marine habitats and taxa (50 taxa across 8 phyla). Significant relationships were found between the incidence of MMEs and the heat exposure associated with MHWs observed both at the surface and across depths. Our findings reveal that the Mediterranean Sea is experiencing an acceleration of the ecological impacts of MHWs which poses an unprecedented threat to its ecosystems’ health and functioning. Overall, we show that increasing the resolution of empirical observation is critical to enhancing our ability to more effectively understand and manage the consequences of climate change.