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A four-year study has warned that rising temperatures in the seas surrounding the UK and the wider north-east Atlantic could destabilize marine food webs. Researchers caution that these changes may weaken ocean health and threaten food security by 2050.
Shifting Marine Biodiversity
The research, led by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) and published in Science Advances, challenges the assumption that marine biodiversity will increase uniformly in middle latitudes like the UK. While previous expectations suggested that warmer waters would attract a more diverse range of species moving from the equator, the new projections reveal a significant predator-prey imbalance.
Elena Couce, a marine ecologist at Cefas and co-lead author of the study, noted that the findings were unexpected. “What surprised us is that warming doesn’t increase or decrease biodiversity across the board,” she said. While species diversity for fish and seabed invertebrates is projected to rise by approximately 12% by mid-century, critical plankton groups are expected to decline. Specifically, phytoplankton and zooplankton diversity could drop by 3% and 7%, respectively, by 2050.
Implications for Ocean Resilience
The seas around the British and Irish Isles, particularly the southern North Sea, are recognized as “marine climate hotspots,” ranking among the 20 fastest-warming regions globally over the past half-century. According to the study, this trend creates a scenario where predator diversity increases while their prey base shrinks, potentially disrupting the entire food chain.
“Our results show that climate change could reshuffle marine biodiversity unevenly across the food web, and that gains in some groups do not necessarily mean the ecosystem as a whole is becoming more resilient,” said Lily Greig, a Cefas marine ecologist and co-lead author. Previous research by Cefas identified “climate winners” such as seabass, sardines, and anchovies, while species like Atlantic cod, coley, and haddock were categorized as “climate losers.”
Policy and Future Management
The international research team, which included experts from the University of East Anglia, the Marine Biological Association, and institutions in Norway, the Netherlands, and Denmark, utilized advanced machine-learning techniques and long-term datasets to model these changes. The researchers hope their work will serve as an “early warning system” for ecosystem shifts.
The findings have already been submitted to the UK government’s review of marine protected areas, which is currently evaluating fishery management strategies. Couce emphasized the necessity of integrating these climate projections into future planning, stating that policymakers must account for the fact that climate change is already actively altering biodiversity when developing management measures.
