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Taking the ocean’s pulse Covering 70% of the Earth’s surface, the oceans are a unique field for scientific research. By improving their understanding of the subtle interplay between currents and carbon flow in the oceans, scientists are helping to protect this fragile environment. Chaos involved in ocean variability Researchers have shown that small-scale (10-200 kilometers) turbulent ocean processes play a role in interannual variations in ocean currents and sea level. A sizeable proportion—as much as 70% on average in the Southern Ocean—of the interannual variability of sea level is chaotic and generated by the ocean, without any direct forcing by the atmosphere. These findings argue in favor of including small-scale oceanic processes in climate prediction systems and raise questions about the predictability of ocean currents. Comet Hartley 2 photographed by NASA’s EPOXI mission from a distance of approximately 700 kilometers. Journal of Climate November 2011 Comet Hartley 2 rekindles debate Geophysical Research Letters August 2011 on the origin of the Earth’s oceans An international team including researchers from France has found that comet Hartley 2 contains water similar to that found in terrestrial oceans. The discovery—achieved by using the European Space Agency’s Herschel infrared telescope—rekindles the debate about the origin of water on the Blue Planet. Although it is generally accepted that small icy bodies from the Solar System brought water to Earth, the contribution from comets may well have been underestimated, as well as the size of the reservoir of small icy bodies that helped to form the oceans. Nature October 2011 Calcareous phytoplankton appears to be very sensitive to ocean acidification. An international study including French researchers shows that although secretion On board the Marion Dufresne during of the calcareous skeleton of a species of the KEOPS 2 campaign. single-celled algae called coccolithophores diminishes when seawater becomes more Understanding the carbon pump acidic, certain heavily calcified strains have adapted to in the Southern Ocean the most corrosive environments. ------------------------------------------- Fifty researchers participated in the KEOPS 2 campaign, which took place in the Southern Ocean off the Kerguelen Islands in October and November 2011. The objective was to understand the working, in this ocean, of the It was thought that the Lost City hydrothermal biological carbon pump, which transfers carbon from the surface to the field, on the Atlantic seafloor, was only deep ocean. Iron deficiency in the region limits phytoplankton growth and habitable by microorganisms. However, the CO2 uptake as a result. These findings should make it easier to predict study of its fossil equivalent, Ghost City, discovered in the effects of natural or artificial iron fertilization of the Southern Ocean on 2008 on the Mid-Atlantic Ridge, shows that the alkaline carbon fluxes and the ecosystem. fluids released in this new type of hydrothermal process can be home to an abundant fauna. KEOPS 2 2 October-29 November 2011 ------------------------------------------- 41 2011 A year at CNRS


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