Icebergs Oasis for Ocean Life
22.06.2007 - Other
According to a new study undertaken by the Monterey Bay Aquarium Research Institute (MBARI), drifting icebergs in the Weddell Sea are having major ecological and chemical impacts on the ocean around them.
As global climate change is causing Antarctic ice shelves to shrink, more drifting icebergs carry with them important terrestrial materials and associated trace nutrients. The minerals which are then released far out at sea as the icebergs begin to melt, serve as "hotspots" for ocean life. Researchers have discovered that these floating islands attract phytoplankton, krill and seabirds from a radius of over 3 kilometres out.
Through satellite images and detailed on-site studies aboard the Antarctic research vessel Laurence M. Gould, scientists discovered that the phytoplankton around the icebergs was enriched with large diatom cells, which are known for their role in productive systems such as upwelling areas or ice-edge communities. As diatoms are the preferred food for krill, it is expected that the krill could contribute to carbon sequestration as waste material containing CO2 sinks to the ocean floor. Hence, by increasing its biological productivity, icebergs "serve as a route for carbon dioxide drawdown [...] as it sinks into deep sea", says oceanographer Ken Smith, first author and principal investigator for the research.
Scientists believe that, overall, biological productivity in the Weddell Sea is increasing by 40% due to drifting icebergs. This property of removing carbon from the atmosphere could thus have significant implications for climate models, needing further studies.