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Uniting on ocean acidification: a radical new approach to monitoring OA impacts at global scale

3 February 2023

A new framework supports the vision for a step change in the global monitoring of OA impacts on marine life
Around one quarter of the CO2 emitted from human activities annually is absorbed by the ocean. This has been shown to affect the chemistry of the seawater, causing a drop in pH which has major implications for many marine species and ecosystems.

Despite the threat that ocean acidification (OA) poses, there is currently no global framework for monitoring its biological impacts, and this is hampering efforts to fully assess the rate and scale of the issue. As such, a team of ocean acidification experts, including scientists from Plymouth Marine Laboratory (PML), have created a new methodology designed to ensure best practice in future OA monitoring and improve globally-coordinated efforts to understand and mitigate its effects.

Drawing on a wealth of data from previous experiments and observations, the publication "Unifying biological field observations to detect and compare ocean acidification impacts across marine species and ecosystems: What to monitor and why" proposes five broad classes of biological indicators that, when coupled with environmental observations including carbonate chemistry, would create a far more advanced understanding of the rate and severity of the biological changes taking place due to ocean acidification globally.

Lead author, PML’s Director of Science and Co-Chair of the Global Ocean Acidification Observing Network (GOA-ON), Professor Steve Widdicombe explains:

“The chemical effects of ocean acidification are well-documented but we still need much better, more detailed and more consistent real-world data on its biological effects.

Over the past two decades, lab experiments and other studies and analyses have shown that ocean acidification can have profound effects on species such as corals, crabs and other shellfish and marine organisms. Higher CO2 levels in seawater make it difficult for shellfish to build their shells and for corals to form their reefs, as these are made of carbonate compounds. This is hugely significant for ecosystems, the wider marine food web and indeed, our own food security.

By establishing a universal methodology we hope to be able to effectively evaluate the rate of change and the various mechanisms that affect ocean acidification across a diverse range of ocean environments.
It’s a very ambitious and innovative step forward but also something that requires rapid and widespread adoption.”

The framework itself presents an approach which considers five fundamental ecosystem traits, all of which span across different marine ecosystems and which have been previously identified as potentially sensitive to ocean acidification.

These are illustrated as follows:


Designed to enable a comparison of the relationships between rates of chemical and biological change under different circumstances, and across regional and global scales, the framework will, in turn, contribute towards UN Sustainable Development Goal 14.3 "Minimize and address the impacts of ocean acidification, including through enhanced scientific cooperation at all levels'.

Crucially, it will also support work towards the achievement of the UN Convention on Biological Diversity (UN CBD) goal to minimise the impacts of ocean acidification (as set out in the Kunming-Montreal Global Biodiversity Framework, adopted in December 2022 at COP15 in Montreal).  

Professor Widdicombe adds:

An improved and inclusive monitoring framework, enabling the combination of chemical and biological data, is vital in terms of how we understand ocean acidification and the impacts it is having -- and will have in future - across marine species and ecosystems. Ultimately, this new approach should help enable the scientific community to contribute even more effectively to the achievement of the UN Decade of Ocean Science vision - ‘the science we need for the ocean we want’. This includes empowering countries and regions with emerging OA science capacity.”

To read the paper in full visit: Unifying biological field observations to detect and compare ocean acidification impacts across marine species and ecosystems: What to monitor and why
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