Northeast Atlantic study projects uneven change across marine food webs

What you need to know

• The researchers modelled biodiversity change through 2100 under three climate scenarios, using long-term survey records and statistical models. Their analysis estimates biodiversity indicators, including the contribution of rare species; it does not directly measure future food-web functioning or fishery production. 14
• Under the study’s mid-range emissions scenario, regional richness generally increases for fish and benthic invertebrates, while zooplankton richness decreases. The paper reports approximate increases of 10 fish taxa and 45 benthic species, and a small zooplankton decline, over the period 1993–2099. 12
• Phytoplankton projections differ by region, adding to the uneven pattern across the four groups. The findings challenge the idea that biodiversity gains in some marine groups necessarily mean the food web as a whole is becoming more resilient. 12
• The study’s authors identify possible disruption to energy transfer between groups as a concern, with potential consequences for fisheries dependent on plankton production. The research does not quantify those consequences or establish that they will occur. 1
• The projections have important limits: model fit is low for some phytoplankton and zooplankton measures, and areas with environmental conditions outside the models’ training range are marked as less reliable. Results also vary with the climate scenario considered. 1

Why this matters

The study suggests that tracking biodiversity changes in individual groups may not, on its own, show how marine food webs are changing. Its projections highlight a potential mismatch between gains in fish and seabed invertebrate richness and declines in plankton, while leaving the consequences for ecosystem functioning and fisheries unresolved. 1

What happens next

A key question is whether the study’s proposed indicators will be taken up in marine management, and whether they lead to changes in protected-area or fisheries policy. The reporting does not establish that either step has been agreed. 1

What we know

• The study covers phytoplankton, zooplankton, benthic invertebrates and fish across the Northeast Atlantic, with projections extending to 2100. 1
• Its main results show gains in fish and benthic richness in many regions, declining zooplankton richness and geographically varied phytoplankton change under the mid-range scenario. 12
• Food-web disruption and food-security effects are presented as potential risks, not observed outcomes or direct model forecasts. 123

What we don't know

• How the projected biodiversity changes will translate into measured food-web functioning, fishery production or seafood supply remains unresolved. 1
• The sensitivity of the projections to different climate scenarios, model fit and locations outside the models’ training range remains an uncertainty identified by the study. 1
• It is not clear whether the proposed indicators will be adopted in marine management or lead to changes in protected-area or fisheries policy. 1

Read the reporting

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