So as better to understand the relationship between phytoplankton blooms and seasonal changes in sea ice, the researchers also used information on sea ice concentrations obtained from the US National Snow and Ice Data Center (NSIDC). Their study covered the period 1998-2007.
They found that ice-edge blooms occurred in all seasonally ice-covered areas and from spring to late summer. They observed ice-edge blooms in 77-89% of locations for which they had adequate data. The blooms usually peaked within 20 days of ice retreat, sometimes forming long belts along the ice edge (greater than 100 km).
"The bloom peak is most often located close to the ice edge," said Dr Yool, "We observed blooms propagating in a wave-like fashion behind the receding ice edge over hundreds of kilometres and over several months, while others remained stationary."
Because of the geography of the Arctic Ocean, sea ice does not always retreat northwards. For example, in Baffin Bay and Davis Strait, west of Greenland, ice shrunk both westward and south-eastward from the north in spring and summer, with phytoplankton blooms propagating along the ice edge as it receded.
"Our findings demonstrate strong biophysical linkage between bloom propagation and sea-ice melt back, which is independent of the actual direction of retreat," said Dr Yool.
These findings are important because they indicate that future change in Arctic sea- ice resulting from climate change could significantly impact the occurrence of phytoplankton blooms as well as the animals further up the food chain that ultimately depend upon them, including fish.
Ice-edge phytoplankton blooms also play an important role in the Arctic carbon cycle. Through photosynthesis, phytoplankton blooms
|Contact: Dr. Rory Howlett|
National Oceanography Centre, Southampton (UK)