2 months at sea to explore the Southern Ocean’s contribution to climate regulation

The Marion Dufresne II sailing in the Southern Ocean. Fred PLANCHON / UBO-LEMAR - To better understand the sequestration of atmospheric CO2 in the ocean, and especially how the chemical elements essential to this storage are supplied, transported and transformed by the oceans, is the goal of the SWINGS oceanographic cruise. To this end, a team coordinated by two CNRS researchers and involving colleagues from Sorbonne University, Toulouse III - Paul Sabatier University, the University of Western Brittany and Aix-Marseille University, will traverse the Southern Ocean from 11 January to 8 March 2021, aboard the Marion Dufresne II research vessel chartered by the French Oceanographic Fleet. The Southern Ocean, which surrounds the Antarctic continent, south of the Atlantic, Pacific and Indian Oceans, wild region that is difficult to explore. It plays a key, yet complex, role in the capture and storage of atmospheric CO2. A wide range of factors need to be taken into account, including biological activity (surface photosynthesis, carbon export to the deep ocean and its sequestration in sediments) and ocean circulation. To understand these processes it is necessary to quantify them, which can be done by measuring what are known as geochemical elements (silica, nitrate, iron, zinc, as well as elements such as thorium, radium and rare earths).