Marine scientists in Plymouth have led a major study highlighting the effects of climate change on the plankton populations in UK seas.
Published as part of a wide-ranging report by the Marine Climate Change Impacts Partnership (MCCIP), it shows there have been extensive changes in plankton ecosystems around the British Isles over the last 60 years.
It says climate variability and ocean warming have had negative impacts on plankton production, biodiversity and species distributions, which have in turn affected fisheries production and other marine life such as seabirds.
The study was written by world-leading researchers from the University of Plymouth, Marine Biological Association (MBA) and Plymouth Marine Laboratory, along with colleagues at Marine Scotland Science and the Centre for Environment Fisheries and Aquaculture Science.
It forms part of the MCCIP Report Card 2020, which summarises 26 individual, peer-reviewed scientific reports to provide detailed evidence of observed and projected climate change impacts and identify emerging issues and knowledge gaps.
Among the key factors highlighted in the plankton report are:
- There has been a shift in the distribution of many plankton and fish species around the planet.
- The North Sea populations of previously dominant and important zooplankton species (the cold water species Calanus finmarchicus, a major food source for fish, shrimp and whales) have declined in biomass by 70% since the 1960s.
- Species with warmer-water affinities (e.g. Calanus helgolandicus) are moving northwards to replace the species, but are not as numerically abundant.
- The decline of the European cod stocks due to overfishing may have been exacerbated by climate warming and climate-induced changes in plankton production.
- Future warming is likely to alter the geographical distribution of primary and secondary open ocean (pelagic) production, affecting ecosystem services such as oxygen production and the removal of carbon dioxide from the atmosphere.