The small but mighty phytoplankton are the labourers of the ocean, they serve as the base of the food web
Researchers from the Âé¶¹´«Ã½ have led the production of a new report highlighting the impact of climate change on marine plankton and pelagic habitats in UK waters.
Published by the , the report discusses the latest evidence showing major large-scale shifts already happening in plankton communities.
It also demonstrates how these effects are being amplified by human activities, including commercial fishing and the development of offshore energy infrastructure, as well as run-off from agriculture and other land-based industries.
The report’s authors also say there are marked differences across areas of the coastal and marine environment, with poor monitoring in some areas leading to a lack of consensus in some of the observed trends and predictions. But overall, they expect to see the effects observed currently to impact the entire marine ecosystem, which will likely affect food web efficiency and productivity into the future.
The new report was authored by a team including Dr Matthew Holland, Professor Abigail McQuatters-Gollop, and Mr Matthew Faith from the University’s Centre for Marine Biology and Conservation Science (CMACS), as well as scientists at the Marine Biological Association, Âé¶¹´«Ã½ Marine Laboratory, Environment Agency, Cefas, the Scottish Government, and the Scottish Association for Marine Science.

I hope this report will help ensure that plankton and pelagic habitats receive greater consideration in marine policy and climate adaptation planning.

Plankton form the foundation of marine food webs, supporting fisheries and playing a fundamental role in carbon cycling, yet they often receive far less attention than more visible parts of the marine environment. By summarising the latest evidence, I hope this report provides policymakers, managers, and the wider public with a better understanding of how climate change is already affecting UK seas, and what future changes could mean for the benefits that our shared marine ecosystem provides to society.

Matthew HollandDr Matthew Holland
Research Fellow and lead author of the new MCCIP report

The new MCCIP report builds on a previous assessment, published in 2020 and also co-authored by scientists from the University. Since then, UK and European researchers have produced a number of studies highlighting the importance of plankton for the entire planet and the ways in which climate change is driving fundamental shifts at the base of the marine food web.
Having been invited by Defra to lead the new report’s production, Dr Holland conducted a targeted review of the scientific literature on climate change impacts on plankton in and around UK waters.
This involved screening more than 500 studies, including research led by the University and supported by Defra’s Marine Natural Capital and Ecosystem Assessment (mNCEA) programme, as well as ongoing work with colleagues across Europe to assess the health of marine ecosystems for OSPAR, the international convention responsible for protecting the North-East Atlantic.
The amassed evidence was then processed according to the type of observed change in plankton communities described, the identified drivers of those changes, and the geographic region where the impacts occurred. Dr Holland also coordinated the group of 17 co-authors, plankton experts from across the UK, drawing on their wide range of expertise to review the evidence, ensure scientific accuracy, and refine the report's key messages.

Plankton may be microscopic lifeforms but they are among the most important organisms on our planet – without them, Earth would be a very different place.

We have been saying for decades that plankton communities are changing as a result of shifts in the global climate and human activities, and more comprehensive evidence is the only way we can bring that to greater attention. This report, and the robust scientific evidence it is based on, can hopefully be another piece of the jigsaw that ultimately leads to joined-up action for marine biodiversity management at a regional and global scale.

Abigail McQuatters-GollopProfessor Abigail McQuatters-Gollop
Professor of Marine Conservation

Outlining the present and future challenges facing the UK’s plankton communities

The new MCCIP report includes detailed descriptions of the current status of plankton communities and pelagic habitats and how they could shift in years to come:

What is already happening?

  • Climate change is driving major shifts in plankton communities and pelagic habitat conditions across UK waters.
  • Long-term monitoring shows declines in large phyto- and zooplankton in oceanic waters beyond the continental shelf, while smaller plankton and microbial species are dominating in warmer, stratified shelf waters. Smaller species transfer energy less efficiently, reducing food availability for predators.
  • Warming and changes in stratification and currents are impacting phyto- and zooplankton species distribution, with some warm-water species spreading northward and contracting their southward distributions, while others are declining in southern areas.
  • The timing of the spring plankton bloom has advanced in many parts of the North Sea, creating risks of mismatch with fish spawning.
  • Gelatinous organisms such as jellyfish are increasing in some regions, likely due to warming as well as changes in predator and prey availability; however, in most regions they remain poorly monitored.
  • Marine heatwaves and other extreme events may impose increasing stresses on plankton communities although their effects are still in early stages of being explored.
  • These climate driven pressures on plankton communities are amplified by eutrophication, changing nutrient ratios, coastal darkening (reduction in water clarity caused by land runoff and climate-driven sediment resuspension), fishing impacts, and offshore energy infrastructure.

What could happen in the future?

  • Future warming is expected to result in earlier and longer lasting spring blooms in some regions, farther northward shifts in phyto- and zooplankton, as well as fish species, reduced overall primary productivity by intensifying water-column stratification and depleting surface nutrients, and increased dominance of smaller phytoplankton and protist species (single-celled eukaryotic organisms) adapted to nutrient-poor conditions.
  • Climate-driven changes in primary productivity and phyto- and zooplankton community composition are expected to adversely impact marine food web functioning and efficiency, reducing the maximum sustainable yield for key fish species in some regions. Fish larvae are also likely to need more prey to survive as warmer water increases metabolic demands.
  • Carbon export to the seafloor is expected to be weakened with declining primary productivity and phytoplankton community shifts towards smaller and slower sinking plankton, reducing the rate at which UK seas remove anthropogenic carbon from the atmosphere.
  • Reduced food web productivity from changes in plankton will have wider impacts to the functioning of the UK marine environment and alter the provision of future ecosystem services, including key fisheries.