From the lab to the ocean

“We know in theory that ocean acidification affects biological organisms in certain ways,” says Natalija Suhareva, a researcher on the IOC-UNESCO Ocean Acidification Research for Sustainability project. “We know which groups of species are more sensitive to ocean acidification, which are less sensitive, and which could even benefit from ocean acidification, thanks to evidence from experimental work.” But laboratory experiments cannot reproduce the full complexity of the ocean. “Reality is much more complex, so we don’t actually know how it happens in the real world. We only know how it happens in a controlled environment.”

The challenge, therefore, was to find a way of connecting changes in ocean chemistry with changes in marine biology. In 2023, GOA-ON published a framework that proposed a new way of approaching the problem: rather than comparing absolute states, researchers should compare rates of change in carbon chemistry with rates of change in biology. “We saw this as an opportunity to develop a new methodology that shows how these two different metrics correlated with each other,” says Steve Widdicombe, director of the Sharjah Marine Science Research Centre at University of Khorfakkan, UAE, and co-chair of GOA-ON. 

The framework identified five biological traits that could be measured: calcification and calcifiers; primary production; heterotrophic secondary production; biodiversity or ecosystem composition; and genetic adaptation. In 2024, the Ocean Acidification - proof of concept for new research strategies project, supported by the Velux Foundation, set out to put that framework into practice. Dr Suhareva and the team began by looking for long-term time series in which biological and chemical observations could be aligned across comparable periods, geographical scales and sampling frequencies.

What they found was a much more serious data gap than expected. In September 2026, the GOA-ON Data Explorer portal contained 799 records of existing time series around the world, but once the researchers had applied filters for duration and frequency of monitoring, carbon chemistry and associated biological measurements, the number fell rapidly. To qualify, datasets needed more than 15 years of carbon chemistry monitoring (excluding the unfinished year of 2026), observations more frequent than once a month and some associated biological data. “Out of nearly 800, fewer than ten records passed all of our filters,” says Dr Suhareva. But incomplete or outdated information in the portal can leave suitable records overlooked, so the findings do not mean that other time series don’t exist. The duration threshold is also a practical screening choice: as monitoring continues, additional records could cross it as early as next year.

Some biological datasets stretched back decades but lacked sufficiently long or consistent carbon chemistry records to accompany them. Other datasets appeared to be long running, but had been sampled too infrequently or inconsistently to provide a reliable time series. “Some claims of longevity were spurious in terms of how often and how consistently they were sampling, making them unreliable,” explains Professor Widdicombe. “The more datasets we examined, the more we had to discard.”

Better data for better decisions

The west coast of North America demonstrates what can happen when there is a direct economic incentive to understand changing ocean conditions. In 2005, shellfisheries began to observe alarming productivity declines linked to ocean acidification; this helped to drive investment in monitoring programmes such as the Pacific Ocean Acidification Project. In 2013, the US Integrated Ocean Observation System Ocean Technology Transition project, in collaboration with the National Oceanic and Atmospheric Administration’s Ocean Acidification Programme, funded five ocean acidification sensor development projects to inform and support the protection of the shellfish industry. “That example showed how local stakeholders and rights-holders who care about the issue can make a big difference in pushing for funding to support relevant monitoring,” says Professor Findlay. GOA-ON has invested in building capacity and training people around the world to engage in ocean observation and monitoring. However, the challenge now is to maintain—and fund—that work year after year. “As old-school as it might be, there is still no substitute for going out and measuring stuff consistently, at high enough frequency and over a sustained period of time,” insists Professor Widdicombe.

Scientists are increasingly emphasising the relevance of ocean acidification to stakeholders, in the hope of building the investment needed to improve monitoring. Aquaculture has already been affected by changing ocean conditions, with some operations adapting their practices in response. More detailed information about the rate and location of acidification could also help inform decisions about where to designate marine protected areas and how to approach marine spatial planning.

Accurate acidification data will become even more important as interest in marine carbon dioxide removal grows. Decisions about deploying ocean-based carbon removal technologies require an understanding of the underlying carbonate chemistry, particularly in coastal waters where conditions can vary considerably over relatively small distances. More broadly, understanding how quickly and where ocean conditions are changing is increasingly important for climate adaptation and marine management. “In everything from climate change adaptation to marine spatial planning and marine protected areas, the whole climate-smart revolution relies on us understanding how things are changing, over what timescale, and what the most appropriate decisions would be,” says Professor Widdicombe.

Monitoring systems for the future

The project has now developed tools that allow researchers to test their own datasets and describe their time series using the methodology. But it has also exposed the scarcity of datasets to which the approach can currently be applied. The researchers therefore have two clear messages: existing long-term observations need to be protected; and new monitoring needs must be designed with future applications in mind. “If we are now entering an era of longer, more frequently sampled carbonate chemistry time series, let’s think in advance about how to marry chemistry with biology to better understand biological responses to ocean acidification,” says Dr Suhareva. Doing so will require closer communication between oceanographic and biological communities. “Oceanographic and biological observations are often collected separately, sometimes by different organisations,” Dr Suhareva adds. Better co-ordination could allow biological observations to be built around existing chemical monitoring stations, creating aligned datasets capable of showing how ecosystems change alongside ocean chemistry.

That principle is being taken forward through a new European Commission project, Safeguarding from Acidification: Feedbacks and Ecosystem Services for European and Global Action (SAFESEA), led by Professor Findlay. One of its central questions is: what do stakeholders need from the ocean acidification community to make informed decisions? And, in turn, what data and modelling are required to support those decisions? “We’ll be taking specific guidance from stakeholders to think about what additional coastal and open-ocean data is needed,” explains Professor Findlay. The project will seek to improve coastal monitoring and incorporate more complex chemical models into coastal models, with the aim of better capturing the processes taking place in these highly variable environments.

Better data could also help translate existing international commitments into measurable results. Target 8 of the Kunming-Montreal Global Biodiversity Framework calls on countries to minimise the impacts of climate change and ocean acidification on biodiversity, yet there is currently no clear indicator for measuring the impact of ocean acidification on biodiversity. “Other targets within that framework had very good and very closely related numerical indicators to measure countries’ progress, but there was no such indicator for acidification,” says Professor Findlay. “Even within the international biodiversity protection community, there’s no guidance on ocean acidification beyond ‘please try and do something’.” 

Developing better, data-informed indicators would not solve the underlying problem, but it could provide a way to track change, assess progress and identify where further action or investment is needed. The challenge now is to ensure that monitoring is sustained long enough to connect changes in ocean chemistry with their consequences for ecosystems and the decisions that depend on them.