The Oceanic Carbon Pump
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The ocean is a climate regulator, mainly because it captures ⅓ of the carbon dioxide (CO2) emitted into the atmosphere each year. This phenomenon of “oceanic carbon pump” is due to a double process: a physical process and a biological process.
The physical process is related to the dissolution of carbon dioxide in water. At the surface between air and water, CO2 reacts with water molecules to form bicarbonate ions. These are dissolved and then carried away by cold, dense water – the dissolution of the gas is favoured in cold, high-latitude waters more than in warm, tropical waters. Through ocean currents, most of this dissolved carbon sinks with the cold, dense water to the sea floor. And it will remain buried there for hundreds of years!
The biological process is linked to the phenomenon of photosynthesis. On the surface of the oceans and from water, sunlight and CO2, the plant plankton synthesises matter by releasing oxygen (O2). It therefore absorbs CO2 and transforms it into organic matter..
But some of this plankton dies and falls to the bottom of the sea, while the other part is ingested by marine organisms in the food chain, which in turn die and fall to the deep sea. Both the dissolved carbon and the carbon absorbed during photosynthesis are therefore stored in the deep sea. This is why our oceans are said to be “great natural carbon sinks”, essential to our human life.
As CO2 is the main greenhouse gas, the oceans are fully playing their role as moderators of global warming: it is estimated that they have already absorbed more than 25% of man-made CO2 emissions since 1950!
However, as the waters warm and global warming increases, the dissolution of CO2 becomes more difficult. Unabsorbed CO2 stagnates in the atmosphere, which only accelerates global warming. This is why oceanographic campaigns and research are so important today: it is essential to better understand the evolution and movements of the ocean in order to better understand tomorrow’s climate phenomena.
A collective human adventure, an exceptional amount of data collected and the beginnings of a science of the sea concerned with its environmental impact: this is how we can sum up the success of this 2022 edition of the 32nd PIRATA oceanographic campaign.
A unique sailing boat, an international low-carbon campaign, that is a world first: it was under these favourable winds that the French sailing boat Blue Observer returned to the port of Brest in March after 96 days at sea in the North and South Atlantic.
More than 28 days since the departure, and the tiredness can be read on all faces. The scientists of the PIRATA-FR32 campaign have not had a single minute to keep a logbook or to send us some "live" news...it doesn't matter: the focus is on watches and measurements!
For several days now, the 14 scientists have been sailing for the 32nd edition of the oceanographic programme PIRATA ("Prediction and Research Moored Array in the Tropical Atlantic"). From the ship "Thalassa" of the French Oceanographic Fleet on which they have embarked, they gave us some news about their journey.
For the 25th consecutive year of the programme, the PIRATA oceanographic campaign left the port of Las Palmas in the Canary Islands on 28 February 2022.
In the spring of 2021 and despite a still complicated health context, scientists spent 42 days criss-crossing the South Atlantic Ocean with the aim of quantifying the most important marine current in the ocean circulation and climate system of our planet.
One of the scientific objectives of the SWINGS campaign was to understand the evolution and development of phytoplankton in the Southern Ocean.
48 sailors on board and 2 months at sea to collect, sample and filter water, with this main objective: to understand how the ocean helps regulate the climate by absorbing atmospheric CO2.
In his programme "La Terre au Carré" on France Inter, Mathieu Vidard looks back at the SWINGS expedition.
Leaving Reunion Island in January 2021, they have been together at the helm of the SWINGS mission for 8 weeks in the heart of the Southern Ocean.
For 8 weeks, 48 scientists and crew members crossed part of the Indian Ocean, passing through the Marion, Crozet, Heard and Kerguelen islands, before returning to Reunion Island 57 days later.
This year, 12 scientists and 25 crew members embarked on the 31st mission of the PIRATA oceanographic programme from the port of Brest (France) instead of the usual port since 2015 of Mindelo (Cape Verde), due to the pandemic.
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