Scientists explain how surface chlorophyll reached 1,000 metres deep
Scientists have solved the mystery of unusually high concentrations of chlorophyll detected more than 1,000 metres beneath the ocean A secret ocean circulation system Unexpected
Scientists have solved the mystery of unusually high concentrations of chlorophyll detected more than 1,000 metres beneath the ocean A secret ocean circulation system Unexpected signal discovered by underwater robots The breakthrough came from readings by autonomous underwater robots called Biogeochemical-Argo floats. Supercomputers to the rescue Major role in storing carbon The study shows that this mechanism accounts for 30 to 50 percent of all organic particles Why the discovery is important Scientists have solved the mystery of unusually high concentrations of chlorophyll detected more than 1,000 metres beneath the ocean surface by autonomous underwater robots after years of puzzling. The discovery, which took place between 2014 and 2017 in the North Atlantic, defied existing knowledge, as chlorophyll, produced by microscopic algae that rely on sunlight, is generally found in the upper layers of the ocean.Now, a new study in Science Advances has identified the mechanism behind this phenomenon, reported Phys Org. According to the research led by scientists from the Institute of Marine Sciences (ICM-CSIC) and the Barcelona Supercomputing Center (BSC-CNS), powerful winter ocean currents have a fast-track for transporting living microalgae and organic matter from the surface to the deep sea, opening up an important pathway for carbon storage and the maintenance of deep-ocean ecosystems.The study was carried out in the subpolar North Atlantic, especially the Labrador and Irminger Seas, where the circulation of the ocean is strongly affected by the harsh winter conditions.
It was found in the study that in winter, cold air and high winds cool the surface waters to make them denser than the water surrounding them. These heavy water masses sink rapidly in a process known as deep convection. Scientists call this an underwater cascade, carrying particles full of nutrients, including living microalgae and organic debris, from the surface down to more than 1,000 metres.This mechanism is far more rapid and can carry material to much greater depths than the slow settling of particles by gravity.According to the study, the breakthrough came from readings by autonomous underwater robots called Biogeochemical-Argo floats. These robotic instruments drift through the ocean, diving and surfacing at different intervals, taking measurements of temperature, salinity, oxygen levels and biological activity. They found surprising spikes of chlorophyll in deep waters in several winters between 2014 and 2017, at depths of around 1,000 metres. It is mentioned in the study that the presence of chlorophyll at such depths suggested that surface material had reached the deep ocean much more quickly than scientists had previously thought possible, since chlorophyll is associated with photosynthetic organisms that live near sunlight.Scientists used field observations and sophisticated computer simulations to determine how the chlorophyll got so deep.
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