Bicycle around the carbon cycle: Tiny Diatoms could offset global warming.
About half the photosynthesis on earth occurs at sea, where tiny phytoplankton such as diatoms “fix” atmospheric carbon dioxide by converting it into organic matter. About 15% of this eventually sinks to the ocean depths, along with the diatom skeletons.
A 13-year study recently reported in PNAS revealed an unexpected and previously undocumented late summer deep sea sequestration of carbon by a symbiotic combination of cyanobacteria and diatoms. Although diatoms are tiny (about 30 could fit into the width of a human hair), their glass-like skeletons are heavy, so that when they die they take carbon out of the surface water, locking it into deep ocean sediments. Scientists speculate that the increase in day length could be a cue for the diatoms to begin sinking en masse, usually around August.
Carbon dioxide levels are higher now than the past 2.1 million years. Natural carbon sequestration by diatoms offers a welcome source of remediation.
Paper (open access):http://www.pnas.org/content/109/6/1842.full