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Atmosphere
Atmos. turbulences
Ocean and climate
Natural Factors
Climatic and oceanic phenomenas
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5st PART
The CO2 (carbonic gas) gas present in the atmosphere is constantly exchanged with biomass (breathing and damage of plants) and the ocean (by solution of gas in water). LBiomass contains about 2 times more CO2 than the atmosphere and the ocean 50 times more ! Every 10 years the CO2 is renewed by exchange with the biomass and the ocean which would mean that this gas is controlled by the ocean. But this control depends above all on the rate of water renewal that is in contact with the atmosphere as carbon transport is dissolved by oceanic currents that directs the oceanic carbon cycle. Thermohaline circulation is the main point driver of this renewal. However, the ocean also contains a significant
biomass: plankton. It is about 10 times lower than the continental
biomass. Oceanic biomass is renewed 10 times faster than the
continental biomass and the rate of organic carbon creation
in the ocean is comparable to that of the continents. Due to their low temperature, Antarctic waters
absorb a lot of CO2. In fact, most oceanic
mass is cold, more it absorbs carbon dioxide.
This animated map shows the seasonal
exchange of CO2 between the atmosphere
Some of the CO2 is
reabsorbed by the ocean, by dissolution in water. Then by
dissolved form this gas can be transported by oceanic currents.
Seaweed and algae assimilate carbon dioxide that goes into
the chain of life. Then by particular form it can either be
deposited in the depths of the abyss or be rapidly remineralized
by the action of bacteria on surface.
The Southern Ocean uptake 30 to 50% of the amount of carbon dioxide conveyed into Earth's atmosphere, while it represents only 10% of the oceanic surface. It is what scientists call a « carbon sinks » . In ten years, within the context of the Antares program they started in 1990 at the initiative of the Brest IUEM the researchers of oceanography discovered this particuliarity of the Antarctic Ocean. They are now able to quantify the amount of CO2 taken up each year by the oceans : 2 billions of tons ! They also discovered over 60 campaigns conducted in the
Southern Ocean, of which some number fullfiled by the «
Marion Dufresne », that this aspiration varies in intensity
depending on the variation of temperature a more or less degree
of the ocean. This temperature variation would be to link
to the effect of El
Nino that occurs regularly in the Pacific and causes considerable
damages on both sides of the ocean.
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