PhD Studentship - Engineering the Ocean-atmosphere Interface: Accelerating Atmospheric CO2 Removal into Seawater

How do you engineer seawater to pull carbon dioxide out of the atmosphere and help to mitigate climate change?

Removing carbon dioxide from the atmosphere at enormous scale is likely to be an important part of tackling climate change. The ocean naturally exchanges CO₂ with the air, but because the alkalinity of that seawater buffers CO₂, the amount of carbon dissolved in the ocean is vastly greater than in the atmosphere. For context, if you took all the CO₂ that humanity has every emitted and stirred it into the ocean, the seawater carbon concentration would only increase by about 2%.

An extremely promising technique, known as Ocean Alkalinity Enhancement, aims to increase the buffering of CO₂ by seawater. This would allow seawater to take up even more atmospheric CO₂, helping us to balance the emissions from activities - such as flying and farming - that we don’t know how to decarbonise, and potentially even begin to reverse climate change.

But there is a fundamental problem.

If we increase the capacity of seawater to store carbon, atmospheric CO₂ does not instantaneously move into the water. The rate at which CO₂ crosses the air-water interface is the major bottleneck, with implications around marine ecosystem impacts, scalability, verification and cost. Overcoming that bottleneck could transform the way marine carbon dioxide removal is designed and deployed. This PhD, part of the CASE4CDR project - aligned with ARIA’s Resilient Climate and Ecosystems Opportunity Space - will investigate how to make that happen.

You will work at the interface of environmental engineering, marine chemistry, enzymology, fluid mechanics, and climate science to understand, quantify and ultimately engineer the transfer of CO₂ from air into seawater.

A major focus will be the development and optimisation of systems designed to maximise gas exchange while minimising the energy, material and environmental costs of carbon removal.

You will design experiments to quantify CO₂ exchange between air and seawater and investigate how performance changes with a wide range of factors. You will establish rigorous carbon budgets to quantify carbon removal. Working closely with a second PhD researcher and the project supervisors, you will explore a potentially transformative way of accelerating this process.

From laboratory experiments to the sea

A particularly exciting feature of this PhD is that, with the right safeguards in place, the work is intended to move beyond laboratory proof-of-concept.

Upon meeting key acceptance criteria, you will help translate fundamental measurements and engineering designs into trials using real seawater at the SeaCURE pilot facility situated on the coast in Weymouth.

This will create a unique opportunity to follow an emerging climate technology through multiple stages of development: from calculations and controlled laboratory experiments, through engineering and instrumentation, to operation in a real marine environment.

Carbon dioxide removal cannot succeed on engineering performance alone.

You will join a wider interdisciplinary project examining what would actually be required to deploy a new marine carbon removal technology responsibly. Alongside your core research, you will have opportunities to contribute to work around environmental permitting, regulation, environmental impacts, public and stakeholder engagement, and trials at the Weymouth plant.

That wider perspective is important. The central question is not just can we build it, but can we develop a carbon-removal system that is measurable, environmentally responsible, socially acceptable and capable of eventually operating at meaningful scale.

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