A pioneering study, published in the journal Nature Geosciences, found that giant icebergs contribute to the storage of atmospheric carbon dioxide much more than previously thought.
Scientists from the University of Sheffield’s Department of Geography discovered that melting water from icebergs had surprisingly high levels of phytoplankton growth – a side benefit of this is a natural form of carbon sequestration, a process that stores carbon dioxide.
Scientists think that melting water from icebergs could be responsible for as much as 20 per cent of the carbon sequestered to the depths of the Southern Ocean. Apparently, the carbon is sequestered in the melting water, along with iron and other nutrients found in iceberg melt, and plunges deep into the ocean where it’s unable to contribute to global warming.
In the study, researchers analysed 175 satellite images from 2003-2010 following a number of giant icebergs (at least 18 km in length) in the Southern Ocean. They monitored ocean color as the icebergs pass by, which is an indicator of phytoplankton productivity at the ocean’s surface.
The research suggests that giant icebergs carry a massive halo of carbon storage. More specifically, evidence shows an enhanced radius of chlorophyll levels surrounding icebergs at least 4-10 times the icebergs length. Results also show enhanced phytoplankton levels extending hundreds of kilometers from giant icebergs, and persisting for at least one month after the iceberg passes.
The Southern Ocean is responsible for about 10 percent of the worlds ocean carbon storage. Previous studies suggested that icebergs played a relatively minor role in phytoplankton uptake of CO2 – but as mentioned before, this study suggests as much as 20 percent of carbon storage in the Southern Ocean is due to icebergs.