A French-British team led by the Laboratoire d’océanographie de Villefranche-sur-Mer (CNRS/Sorbonne University) has just discovered that a little-known process regulates how the oceans can sequester carbon dioxide (CO2). At the ocean surface, photosynthesis by phytoplankton transforms atmospheric CO2 into organic particles, some of which then fall to the bottom. This essential mechanism allows part of the ocean’s carbon to be sequestered. Between 100 and 1000 metres below the surface, however, about 70% of this particle flux is lost. Although previous studies have revealed that small animals can take up 50% of this flux, no measurements had been made to explain what happens to the other half.
Using a fleet of robots deployed in different oceans, the scientists have now revealed that about 35% of this flux is broken down into finer particles.
Meanwhile, an international team of researchers involving a chemist from CNRS are the first to have shown that DNA quadruplexes (quadruple helix structures that are more complex than the double helix) are markers of neuronal aging and negatively affect autophagy – a primordial process for neurons because of its protective effect against neurodegenerative diseases. The findings highlight the precautions that must be taken when using quadruplex ligands as anticancer agents, because these compounds could trigger neuronal disorders symptomatic of age-related diseases, say the researchers.