SeaCURE at SEA LIFE Weymouth: What's Happening and Why

Do we need to remove Carbon Dioxide from the atmosphere? Isn’t that just an excuse to keep burning fossil fuels?

While deep cuts to greenhouse gas emissions remain the top priority, some sectors are extremely difficult to decarbonise. CO₂ removal must therefore compliment emissions reductions to get us to Net Zero and stabilise the climate. Net Zero is part of UK policy, for context click here.

What is SeaCURE?

SeaCURE is a research project that is developing and testing technology that could allow the ocean to absorb more CO₂ from the air, helping us to reach Net Zero. It is also researching the potential implications of the technology.

Why the ocean?

The ocean already holds and absorbs a large share of human-made CO₂ (for an explanation click here). Capturing carbon from seawater, or allowing the water to hold more carbon, could be more practical than capturing that carbon from air, and it doesn't compete for space on land.

Where & who?

The SeaCURE project has been led and run by the University of Exeter, with the Plymouth Marine Laboritory, Brunel University of London and Eliquo Hydrok.

We've built the world's first research-dedicated seawater carbon capture plant at SEA LIFE Weymouth. SEA LIFE has a strong commitment to marine science and sustainability, a pumped seawater system and space for trialing technology. Together with the wealth of data we have about English Channel's biology and chemistry, these factors make Weymouth is an exceptional location for understanding ocean approaches to carbon removal.

The initial project was funded by the UK Government’s Department for Energy, Security and Net Zero from 2021 to May 2025. Since May we have been supported by the University of Exeter, and the Carbon to Sea Initiative have funded workshops to understand how the local community would like this research to progress. This work will inform future funding bids aiming to support the site as a global research hub which can examine a wider set of ocean carbon removal questions in detail.

How does the process work and what has the SeaCURE plant demonstrated?

Seawater is drawn in, briefly acidified to release CO₂ gas, then the added acid is neutralised; the low‑carbon water returns to the sea ready to take up more CO₂.

Click here for a one minute explainer of the process, or for more detail click here for a three minute explainer.

Within the SeaCURE project we have been exploring the key questions we need answers to, if a technology like this is to be part of the solution to climate change.

What happens to the CO₂?

At scale the CO₂ can be stored deep underground or used industrially in processes that lock it away. For the small amounts removed during testing to demonstrate the process, it is currently released.

What about impacts on marine life?

Our pilot plant does not present a risk to marine life because the low-carbon seawater is released slowly and mixes rapidly with normal seawater. The plant uses automated controls to keep the pH of the released water below 9.5 (the upper limit for UK drinking water), which ensures compliance with our Environment Agency Permit. For more details on the permit, click here.

However, releasing low-carbon seawater into the ocean at larger scales could have unintended ecosystem impacts. Other than one recently published paper, there is currently very little research available on the potential effects of low carbon water, although more research has been conducted on other ocean carbon removal approaches.

A key research priority for the SeaCURE project is to understand whether and to what extent marine impacts could occur if this technology, or similar technologies, are scaled up. To begin addressing these questions, we have carried out laboratory experiments that investigate the effects of low-carbon seawater on marine plankton (tiny plants and animals that live in the ocean) and blue mussels. To find out about the laboratory experiments click here.

What's next?

We've shown from a two-month trial that we can remove carbon from seawater, but there is a lot more to be done. The ocean is complex and changes with tides, seasons and between years. Building a full understanding will take time and a lot more work. Our next priorities are to:

• Understand long term, real world impacts that small lab tests can't capture.
• Clearly show that removing CO₂ from the ocean translates to CO₂ removal from the air, and quantify the efficiency of the removal.

Meanwhile, we're keeping an open mind. It's too early to know which carbon removal methods will work best, and we are likely to need different solutions in different situations. We are particularly interested in a closely related approach to the one we have studied so far, where the seawater holds additional carbon rather than having its CO₂ 'squeezed out' to then be stored elsewhere. For a brief overview of this approach click here and for more detail click here.

The facility in Weymouth is globally unique. Continued research here helps us gather real world evidence responsibly. This evidence will help the public and policymakers decide whether ocean based carbon removal can—and should—play a part in tackling climate change, and how best to do this.

Click here for an overview of the kind of activity that could happen from SEA LIFE over the coming years.