Nutrients From Deep-Sea Vents a Key Factor in Carbon Storage, Study Says

Hot, nutrient-rich water seeping from a network of deep-sea volcanoes provides a consistent source of iron for the phytoplankton that soaks up carbon dioxide, playing a key role in limiting climate change, according to a new study by French and Australian scientists. The world’s oceans capture about 25 percent of the carbon dioxide emitted by human activities, including the burning of fossil fuels, scientists say. Among the largest “carbon sinks” is the Southern Ocean between Antarctica and Australia. Underpinning that cycle is the microscopic plant phytoplankton, which absorbs the carbon dioxide at the ocean surface and then eventually carries it to the ocean floor. While it is well known that iron carried in dust or in coastal sediments can trigger phytoplankton blooms, the extent and consistency of deep-sea vents as a source of nutrients was not as well understood, according to the study published in the journal Nature Geoscience. That source, researchers say, produces between 5 and 15 percent of the total carbon storage in the entire Southern Ocean, and as much as 30 percent in some parts.