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Climate action
17 Nov 2022
Vast phytoplankton blooms may be lurking beneath Antarctic ice
by Angharad Brewer Gillham, Frontiers science writer Image: Shutterstock.com Researchers using NASA’s Earth observing system find that Antarctic sea ice allows enough light in to let hidden phytoplankton bloom in the Southern Ocean. Until now, we thought the packed sea ice of the Southern Ocean blocked all light from reaching the sea beneath, preventing phytoplankton — tiny algae which are the base of aquatic food webs — from growing there. The less light available, the less the phytoplankton can photosynthesize and therefore the less phytoplankton there will be, heavily restricting life beneath the ice. But research inspired by increasing under-ice blooms of phytoplankton in the Arctic has shown that Antarctic waters also have unexpected denizens, indicating that there is underestimated ecological variability under the ice. Blooms are often spotted as soon as the sea ice begins its seasonal retreat, supported by plenty of light and freshwater with high iron content. Yet a team led by Dr Christopher Horvat of Brown University and the University of Auckland suspected that there would already be potential phytoplankton blooms in waiting. Writing in Frontiers in Marine Science, they described using sampling from independent BGC-Argo floats and climate model output to estimate light availability beneath […]