London, Jan 30 (ANI): An Indo-German project that aims to dump iron in the ocean to fix the climate by capturing carbon dioxide (CO2) from the atmosphere, is now under way in the Southern Ocean.
According to a report in New Scientist, the project hopes that by dumping iron into the water, plankton blooms could be stimulated, which will absorb CO2 from the atmosphere.
When the plankton die and drop to the ocean floor, they should drag carbon down with them.
To investigate how much carbon gets dragged down and stored on the sea floor and how much is recycled higher up in the water column, Raymond Pollard of the National Oceanography Centre in Southampton, UK, and colleagues set up a number of sediment traps around the Crozet islands in the Southern Ocean.
Plankton bloom naturally every year north of Crozet, boosted by the iron swept off the island's volcanic flanks.
Pollard and colleagues monitored the fallout from one of these blooms 100 meters and 300 meters beneath the surface, and compared this with the carbon fallout in an area that did not bloom.
They found that three times as much carbon falls to the sea floor beneath a bloom as in "clear" waters. Sediment cores taken from the sea floor suggest the carbon stays there for thousands of years.
"Our carbon-to-iron ratio is 80 times less than one reported by another study a year ago," said Pollard. He believes the previous experiment underestimated the amount of iron that was seeping into the bloom area.
He said that the more optimistic figure "was so high it might have given geoengineers great hope that they could stick in not much iron and get huge quantities of carbon sequestered".
According to Pollard, artificial schemes might be more effective than natural blooms at boosting carbon stores.
Suddenly, dumping large amounts of iron overboard is quite different from the slow flow of iron into the ocean through natural processes, and it is possible that this would prompt different species of plankton to bloom and sequester more carbon.
To test this possibility, Pollard welcomes open-ocean experiments such as the German-Indian project, now under way in the Southern Ocean. (ANI)