How healthy is the North-East Atlantic? Findings from the 2023 OSPAR Quality Status Report
13 September 2023
OSPAR Quality Status Reports (QSR) provide a comprehensive assessment of the NE Atlantic and its adjacent shelves, fulfilling international policy obligations to report on the health of our seas. This is important as OSPAR is the mechanism by which 15 Governments & the EU cooperate to protect the marine environment of the North-East Atlantic.
Their aim is to assess the environmental status of the North-East Atlantic against baseline indicators, to find out whether offshore waters in Europe are of ‘Good Environmental Status’, to support EU member state obligations under the Marine Strategy Framework Directive (MSFD).
The objective of the MSFD is to have a clean, healthy and biologically diverse North-East Atlantic Ocean, which is productive, used sustainably and resilient to climate change and ocean acidification.
400 scientific experts from the EU and UK have contributed to 120 assessment reports on the health and status of the North-east Atlantic and its fringing European shelf seas (with 50 of these now published on the OSPAR website), with a significant number of our own scientists playing leading roles such as chapter co-leads and contributing expert scientific evidence across a range of issues.
The Western Channel Observatory (WCO) time series, a marine dataset situated in the Western English Channel, has been a vital source for the monitoring and assessment of trends in these subject areas, enabling our scientists to contribute expertise from a wealth of data. The WCO is the longest, near-continuous marine dataset in the world - data collection began back in 1903. The data and knowledge generated at the WCO allows us to better understand the causes and consequences of some of the largest environmental issues we are currently facing, such as climate change, ocean acidification, biodiversity loss and pollution.
The main conclusions from our scientists’ reports are as follows:
Eutrophication still persists in some river plumes and coastal areas of the North-east Atlantic, and in some catchments, it has even increased. Nature-based solutions to controlling eutrophication are being explored through the use of wetlands that filter and capture nutrients.
Plankton are impacted in pelagic habitats. Phytoplankton and zooplankton form the base of the marine food web and support species higher in the food web including birds, fish and marine mammals. The new report shows that there has been a decrease in the abundance and biomass of phytoplankton and key zooplankton groups, due to changes in water column dynamics (mainly increased stratification linked to the rise in global temperatures).
Ocean acidification puts marine ecosystems at further risk. Ocean acidification occurs because at least a quarter of the CO2 released into the atmosphere by human activities is being absorbed by the ocean, changing its carbon chemistry through an increase in acidity, and reduced availability of carbonate ions. This change in the prevailing chemical environment affects marine organisms, with direct effects especially for calcareous habitats and calcifying organisms, threatening indirect consequences for entire marine ecosystems.
The state of the marine food web is of great concern. Shifts in nutrient inputs have affected primary production and fisheries, while shipping and maritime infrastructure have impacted higher level organisms. Specifically, demersal fish did not achieve good environmental status in the Greater North Sea and Celtic Sea.
The effects of climate change are clearly seen. Climate change is causing ocean warming, ocean acidification, decreased oxygen, marine heatwaves and sea level rise, all of which have a negative impact on marine ecosystems. These can result in increased storm intensity, increased risk of flooding, and changes in rainfall patterns. Climate change has shifted species distributions, changed primary productivity and altered trophic interactions.
Underpinning many of these assessments is the data and research on primary productivity, that sustains the functioning of marine food webs, to which PML made a major contribution. The main findings from this report are that from 1997 to 2019, primary production was stable in the Greater North Sea, Celtic Seas and Bay of Biscay and Iberian Coast. Primary production decreased significantly however from 2015-2019, which is likely to be driven by both reduced nutrient availability and climate change.
Dr Tilstone, Bio-optical Oceanographer, commented: “This is the first pilot assessment of primary production, which we have shown to be a more sensitive indicator of disturbance in the marine environment compared to Chlorophyll-a biomass alone. The decrease in phytoplankton productivity in many areas of the North-east Atlantic will inevitably have knock-on effects higher up the food chain and may affect the abundance of fish, birds and marine mammals.”
Dr Angus Atkinson, Marine Ecologist at PML, added, "This assessment is based on a network of time series from multiple laboratories across the UK and rest of Europe. It shows some worrying declines in some of the key plankton groups, and while the scale of the decline points to large scale climatic warming as the ultimate cause, we still need to understand why some species and regions are changing faster than others."
And given the multidisciplinary requirements to produce such a comprehensive report, three of our ocean acidification experts also contributed to the OSPAR QSR, including our Director of Science – Professor Steve Widdicombe, Biological Oceanographer - Professor Helen Findlay and Marine Ecosystem Modeller - Dr Yuri Artioli.
Professor Steve Widdicombe, who is also Co-chair of the Global Ocean Acidification Observing Network (GOA-ON) Executive Council, said: “Ocean acidification has often been referred to as ‘the other carbon problem’. Carbon is released into the atmosphere from human activities, like the burning of fossil fuels, but not all of it stays there. At least a quarter of the CO2 released into the atmosphere by humans is then absorbed by the ocean, where it changes its carbon chemistry. This change in the prevailing chemical environment affects marine organisms, with direct effects especially for calcareous habitats and calcifying organisms, and indirect consequences for entire marine ecosystems.”
“And ocean acidification has been observed in all OSPAR Regions during the past decades. It is projected to keep occurring, and even accelerate under the higher carbon dioxide emission scenarios.”
Professor Helen Findlay, who is also Chair of Northeast Atlantic Ocean Acidification (NEA-OA) Hub, co-led chapter 3 of the Ocean Acidification Assessment - Ocean Acidification Trends and Variability in the OSPAR Maritime Area. She said:
“Ocean acidification has been observed over the past decades, both in coastal areas and in the open ocean – and throughout the water column. The rate of acidification, however, varies between regions. The data from coastal areas is particularly worrying - pH is declining at faster rates in the shallow coastal regions than observed in the open oceans. This is because coastal and shelf seas are significantly more complex in terms of physicochemical conditions due to the interaction of multiple drivers; such as freshwater from rivers, wastewaters, mixing, upwelling, biological processes, and sediment interactions. These conditions can create a perfect storm for acidity. And, considering coastal regions are where we humans interact most with the ocean, we must anticipate the effects.”
Dr Yuri Artioli, who is also a member of the Executive committee of the Northeast Atlantic hub of Global Ocean Acidification Observing Network, co-led chapter 4 of the Ocean Acidification Assessment - Projections of Future Ocean Acidification. Dr Yuri is a part of our Marine Systems Modelling team, working with computer models to project future rates and effects of ocean acidification. He said:
“We have projected ocean acidification in models in OSPAR Regions I to IV, for the period up to 2050, using two regional models and two emissions scenarios (high-emission and mid-emission scenarios). Unfortunately, ocean acidification is projected to occur in all four of those OSPAR regions, with stronger acidification projected with the higher emission scenarios, which is projected to accelerate towards the end of this century.”
“In terms of the effects of this ocean acidification, models have shown that part of the seafloor is projected to be corrosive to exposed calcareous structures. In the European shelf, in the mid-emission scenario, this condition will be seasonal and only occurring in a small region, but it will impact a large part of the seafloor in the high emission scenario by 2100. The deep arctic basin is projected to be already corrosive to exposed calcareous structures, and in the high emission scenario this area is projected to double.”
“These are possible future scenarios – but they are not a reality, yet. Models give some foresight to make changes now, for a better tomorrow.”
OSPAR Indicator Assessment reports involving PML scientists include:
Changes in phytoplankton biomass and zooplankton abundance
Changes in plankton diversity
Changes in phytoplankton and zooplankton communities
Concentrations of Chlorophyll-a
Concentrations of winter nutrients
Pilot assessment of primary productivity
Ocean Acidification in the OSPAR Maritime Area – Assessment Summary and Recommendations
Ocean Acidification Trends and Variability in the OSPAR Maritime Area
Projections of Future Ocean Acidification
Ocean acidification impacts on ecosystems and ecosystem services
Climate change mitigation and adaptation: an ocean acidification perspective
The work on primary productivity conducted by Dr. Tilstone and Dr. Peter Land from Plymouth Marine Laboratory was funded by the European Maritime and Fisheries Fund through the project: “North-east Atlantic project on biodiversity and eutrophication assessment integration and creation of effective measures (NEA PANACEA)”, financed by the European Union’s DG ENV/MSFD 2020, under agreement No. 110661/2020/839628/SUB/ENV.C.2.
Relevant publications -