Exploring the ecology of the sea

Research spotlight: CHALKY

CHALKY (Coccolithophore controls on ocean alkalinity) is a three-year project exploring the ecology of microscopic algae, called coccolithophores, and how their calcification is impacting the oceans’ ability to absorb and store carbon dioxide from the atmosphere.

Led by Lyell Centre expert in plankton ecology and biogeochemistry, Professor Alex Poulton, the ambitious project operates in conjunction with two other studies, funded as part of BIO-Carbon (Biological Influence on Future Ocean Storage of Carbon), a strategic research programme supported by UKRI’s NERC (Natural and Environmental Research Centre) to address pressing questions on how marine life helps the ocean store huge amounts of carbon dioxide that would otherwise be in the atmosphere.

In May 2024, Alex and a team of researchers from 30 national and international science organisations, set-off on a 37-day expedition, aboard the RRS Discovery from Southampton and travelling to the North Atlantic (Iceland Basin) to conduct fieldwork that seeks to address the three climate change challenges that the BIO-Carbon programme is looking to solve.

Alex and his team led the first area of fieldwork, using innovative new sensors on ocean robots, satellites, and the ship itself to look at how biological processes, such as viral infection and grazing by small animals, affect coccolithophores and the fate of the carbon they fix from the atmosphere. The team then conducted novel measurements and experiments-at-sea to assess whether the ‘bloom’ observed – referred to as “turquoise waters” or “white tides” by fishermen - are negatively impacting the North Atlantic’s capacity to absorb carbon dioxide.

Their findings will complement the other areas of fieldwork conducted as part of the expedition. The second, led by the University of Southampton, explored how efficiently marine life converts nutrients into organic material in the surface of the ocean, and the third, led by the National Oceanography Centre (NOC), used advanced cameras and autonomous vehicles to quantify how sinking organic material is eaten and respired, which controls how much carbon is stored in the ocean for hundreds to thousands of years.

The next stage of the programme will combine the cumulative knowledge to produce new models, enabling an informed, interdisciplinary approach to future assessment of the ocean’s carbon sink abilities.