“Oceans are one of the main driving forces of the Earth’s climate”

Núria Casacuberta Arola studies water circulation using radionuclides to understand the role of the oceans in mitigating climate change.
Núria Casacuberta Arola studies water circulation using radionuclides. (Photography: Daniel Rihs)

You’re an oceanographer, so what drew you to Zurich, which is so far away from the sea?

Worldwide there are only a handful of instruments able to measure environmental radioactivity – and ETH Zurich has one of them! These accelerator mass spectrometers can count even just a few atoms of radioisotopes in seawater. We use them to measure very long-lived radionuclides that have been introduced to the oceans by either natural or human activity.

What personal qualities are essential for working on a research vessel in the Arctic?

Above all, you need to be motivated and enthusiastic. Spending two to three months in one of the most remote places on Earth, often without internet access, is certainly an exceptional adventure – but it takes a lot of mental and physical strength! We all feel like different people when we come back.

As a postdoc, you studied the spread of radio­active contaminants after the Fukushima nuclear disaster. What was your most important finding?

During our first expedition off the coast of Fukushima, we were able to quantify the amounts of radioactivity that had been released into the Pacific Ocean. These estimated quantities did not put living organisms at risk. However, since concentrations of some radionuclides had increased by up to 2 to 3 orders of magnitude, we were able to use the spread of Cesium-137 to build an understanding of the surface circulation in the Pacific Ocean.

Why is it important to understand the circulation of the ocean?

Oceans are one of the main driving forces of the Earth’s climate, as they store and transport heat and carbon. A good knowledge of ocean circulation pathways and transport timescales is key to understanding the role that oceans play in mitigating climate change. The Arctic and North Atlantic oceans are of particular interest today, as these are two of the areas most vulnerable to global warming.

The European Research Council (ERC) is funding your current project, TITANICA. What’s the goal here?

At TITANICA, we’re investigating the pathways, transport timescales and mixing of waters 
in the Arctic and Atlantic oceans. What’s groundbreaking is that we use a quartet of radionuclides with different sources and input functions. The project will deploy cutting-edge counting techniques that have recently revolutionised the field of tracer oceanography.

This article appeared in the 21/04 issue of the ETH magazine Globe.

Further information

Núria Casacuberta Arola is Assistant Professor of Physical Oceanography at the Department of Environmental Systems Science at ETH Zurich.