The warming waters surrounding the UK and the broader northeast Atlantic pose a significant threat to marine ecosystems, potentially destabilizing food webs and impacting food security by 2050, according to a comprehensive four-year study. The findings reveal unexpected shifts in marine biodiversity, challenging the notion that mid-latitude regions like the UK would see an overall increase in marine life diversity.
Research conducted by scientists on four critical groups of marine organisms highlights a troubling predator-prey imbalance. This imbalance may lead to unforeseen transformations within marine ecosystems, particularly in the “marine climate hotspots” of the British Isles, including the rapidly warming southern North Sea. Over the past five decades, these areas have been identified as some of the fastest-warming regions globally.
Under a projected warming scenario of 3C by 2100, the study predicts a rise in diversity among fish and seabed invertebrates by mid-century. However, crucial plankton groups, essential to the marine food chain, are expected to decline. “What surprised us is that warming doesn’t increase or decrease biodiversity across the board,” said Elena Couce, a marine ecologist at the Centre for Environment, Fisheries and Aquaculture Science (Cefas) and co-lead author of the study.
While gains are anticipated in species higher up the food chain, such as fish, key plankton groups that support marine ecosystems could lose species. The research, led by Cefas and published in Science Advances, included contributions from international teams across several prestigious institutions.
As temperatures rise, species from equatorial regions are expected to migrate north and south. “The UK is in the middle latitudes. So we expected diversity to go up, because you get species from the south that are more diverse than the species you lose to the north,” Couce explained.
Previous research identified climate “winners” like anchovies, seabass, and sardines in north-western European waters, with species like Atlantic cod and haddock potentially being “losers” in the changing climate.
The study, which spans the UK, Ireland, and France, forecasts a 12% increase in fish and seabed invertebrate diversity by 2050, contrasting with a decline of approximately 3% and 7% in phytoplankton and zooplankton diversity, respectively. “If predator diversity rises while prey diversity falls, that has the potential to disrupt the food chain,” remarked Lily Greig, a marine ecologist at Cefas and co-lead author. “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.”
By pinpointing areas of rapid biodiversity change and identifying vulnerable parts of the ecosystem, the study offers an “early warning system” for potential ecosystem alterations. The findings have been submitted to the government’s review of marine protected areas, which examines fishery management strategies. “Policymakers have a mandate to try to preserve or even increase biodiversity,” Couce stated. “What we are trying to tell them is climate change is already changing biodiversity, and you need to take that into account before you can make other management plans.”
Utilizing extensive long-term datasets and advanced machine-learning techniques, the scientists established the link between biodiversity and environmental shifts, enabling them to project climate-driven biodiversity changes through 2100.
Original Story at www.theguardian.com