Mesopelagic fishes’ biomass much greater than previously estimated, study finds.
The biomass of mesopelagic fishes – which live at depths between 200 and 1000 meters under the ocean’s surface – is ten times higher than the 1000 million tonnes previously estimated from trawling activities.
A team of researches, led by the director of the Red Sea Center at King Abdullah University of Science and Technology, Xavier Irigoien, published their findings in March 2014 in Nature Communications. Their results came from acoustic observations taken during Malaspina 2010, a Spanish circumnavigation expedition.
The mesopelagic zone, located between the sunlit surface waters and the black abyss below, is home to the most abundant vertebrate population of Earth. Each night, schools of mesopelagic fish swim up from the deep ocean to the surface to feed on drifting zooplankton, before descending again at dawn having consumed a significant quantity of organic material. By doing so, they capture large quantities of carbon and release it into the deep waters much faster than any other organism. The new sty-rudy shows how mesopelagic fishes accelerate the ’biological pump’ by eliminating CO2 from the surface waters and transforming it in the form of feces in deeper ocean layers.
credits : Louise Sarant, Ameer Abdullah, Xavier Irigoien.