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Climate Change and Human Influence Perturb Marine Ecosystems

A new study published in Global Change Biology reports that in the last 60 years, the UK’s plankton population, which includes microscopic algae and animals supporting the entire marine food web, has undergone tremendous changes.

The Continuous Plankton Recorder device is towed in surface waters and occupies a similar space to a marine mammal. Image Credit: Marine Biological Association.

The study, which was led by the University of Plymouth and involved leading marine scientists from across the United Kingdom, integrates, for the first time, the outcomes of UK offshore surveys like the Continuous Plankton Recorder (CPR) and UK inshore long-term time-series.

The next step was to map the observations against recorded variations in sea surface temperature to unravel the impact of changing climate on these extremely sensitive marine communities.

According to the researchers, the study outcomes offer further evidence that higher direct human pressures on the marine environment—together with climate-induced changes—are affecting marine ecosystems worldwide.

Furthermore, they noted it is vital to gain insights into wider changes across UK waters. This is because any changes in plankton communities could have negative impacts on the marine ecosystem and the services it offers.

The plankton population forms the basis of the marine food web, and hence changes in the plankton could possibly lead to changes in sea birds, commercial fish stocks, and even the ability of the ocean to offer the oxygen that humans breathe.

Studies of plankton functional groups demonstrated profound long-term changes, which were consistent over wider geographical areas very close to the UK coastline.

For instance, a comparison of CPR samples from the North Sea, during increasing sea surface temperatures showed that the 1998–2017 decadal average abundance of meroplankton—a class of animal plankton including crabs and lobsters that spend their adult lives on the seafloor—was 2.3 times that for 1958–1967.

This was contrary to a general decline in the population of planktons that spend their entire lives in the water column, while the population of other offshore species decreased by around 75%. The research was headed by former postdoctoral researcher Dr Jacob Bedford and Dr Abigail McQuatters-Gollop, from the University of Plymouth’s Marine Conservation Research Group.

Other contributors to the study were researchers from The Marine Biological Association, Plymouth Marine Laboratory, The Environment Agency, Marine Scotland Science, Centre for Environment Fisheries and Aquaculture Science (Cefas), Agri-Food & Biosciences Institute of Northern Ireland, and the Scottish Association for Marine Science.

Plankton are the base of the entire marine food web. But our work is showing that climate change has caused plankton around UK waters to experience a significant reorganisation. These changes in the plankton suggest alterations to the entire marine ecosystem and have consequences for marine biodiversity, climate change (carbon cycling) and food webs including commercial fisheries.

Dr McQuatters-Gollop, Lead Scientist for Pelagic Habitats Policy, United Kindom

According to Dr Clare Ostle, of the Marine Biological Association’s Continuous Plankton Recorder (CPR) Survey, “Changes in plankton communities not only affect many levels of marine ecosystems but also the people that depend on them, notably through the effects on commercial fish stocks.”

This research is a great example of how different datasets—including CPR data—can be brought together to investigate long-term changes in important plankton groups with increasing temperature. These kind of collaborative studies are important for guiding policy and assessments of our changing environment.

Dr Clare Ostle, Continuous Plankton Recorder Survey, Marine Biological Association

Study co-author Professor Paul Tett, from the Scottish Association for Marine Science (SAMS) in Oban, said, “In this paper, we have tried to turn decades of speculation into evidence. It has long been thought that warming seas impact on plankton, the most important organisms in the marine food web.”

By bringing together such a large, long-term dataset from around the UK for the first time, we have discovered that the picture is a complex one. We therefore need to build on the success of this collaboration by further supporting the Continuous Plankton Recorder and the inshore plankton observatories.

Paul Tett, Professor, Scottish Association for Marine Science


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