Type to search

Marine Science


Significant changes in Scotland’s marine food web

Significant changes in Scotland’s marine food web

Scotland’s latest Marine Assessment reveals significant changes are taking place at the heart of the marine food web, with potential for impacts on the wider pelagic environment.

For the first time, a team of researchers has published an assessment based on all available plankton time-series data from Scottish waters to investigate the current state of the plankton community, and therefore ocean health, and to identify if it has changed over time.

Researchers from Marine Scotland Science, Scottish Environment Protection Agency, the Scottish Association for Marine Science and the Marine Biological Association worked together to combine available plankton data in an attempt to understand conditions in the pelagic environment. Plankton form the very base of the marine foodweb and are excellent indicators of marine health. This combined approach allowed broad-scale data from the Continuous Plankton Recorder (CPR) Survey (operated by the MBA) to be analysed together with data from a number of high-frequency fixed point plankton sampling sites. Combined, these data provide a comprehensive picture of the current health of Scottish waters, and offers context for any observed changes, enabling local vs. wide scale changes to be identified.

Researchers working on this assessment used a standard approach to collate the different datasets based on plankton “lifeforms”. By assigning plankton taxa to different groups based on biological traits e.g. size, shape, feeding mechanism etc., this method allowed the combination of disparate datasets. Assessing these data against each other provides important and meaningful information regarding the changes in the state of the pelagic realm.

This assessment revealed significant changes in the abundance of several plankton lifeforms over the last 30 years, with both increases and decreases of different lifeform groups being reported. Currently, there is no defined threshold to assess whether the plankton community are in a ‘good’ or ‘bad’ condition. However, being able to detect these changes is an important step in understanding the overall health of the marine environment, as they have the potential to affect the wider marine community, e.g. commercially important fish species, marine birds and mammals.

David Johns, Head of the CPR Survey at the Marine Biological Association said ‘it’s vitally important we use our valuable long term data to get a better understanding of changes in our marine environment – working with our colleagues in Scotland has allowed us to look at both the finer local scales, up to changes in the open ocean. These reports help to shape future policy decisions, and protect our oceans from multiple impacts’.

This important assessment was produced by a large group of experts from several leading research institutes in the UK, and will be used to underpin significant policy decisions in Scottish waters now and in the future. For further information, visit https://marine.gov.scot/sma/assessment/plankton