Up until last year, we had a
decade of general ice loss in the Arctic . This led to more open water and the earlier
blooms noted here. As the ice retreats,
the Arctic expands its food chain hugely.
After this winter, I am expecting
a powerful reversal of this behavior, so we will have our eyes open for
reports. We should have a late spring
breakup. In Vancouver , the cherry blossoms are just now
breaking out. No February bloom this
year and no lost ski days.
So all of north
America had a severe winter by any standard.
Yet what is important here is
that this work independently confirms the decadal change that took place in the
Arctic .
Scripps Oceanography Researchers Discover Arctic Blooms Occurring
Earlier
Ice edge blooms often follow retreating ice, as shown here on July 5,
2007, south of Wrangel Island in the eastern Chukchi Sea .
Satellite data captured by the NASA MODIS-Aqua
sensor, processed by Mati Kahru. Credit: Scripps Institution of Oceanography,
UC San Diego
by Staff Writers
Warming temperatures and melting ice in the
Scientists at Scripps Institution of Oceanography at
UC San Diego, along with colleagues in Portugal and Mexico, plotted the yearly
spring bloom of phytoplankton-tiny plants at the base of the ocean food
chain-in the Arctic Ocean and found the peak timing of the event has been
progressing earlier each year for more than a decade. The researchers analyzed
satellite data depicting ocean color
and phytoplankton production to determine that the spring bloom has come up to
50 days earlier in some areas in that time span.
The earlier Arctic blooms have roughly occurred in areas where ice
concentrations have dwindled and created gaps that make early blooms possible,
say the researchers, who publish their findings in the March 9 edition of the
journal Global Change Biology.
During the one- to two-week spring bloom, which occurs in warm as well
as cold regions, a major influx of new organic carbon enters the marine ecosystem through
a massive peak in phytoplankton photosynthesis, which converts carbon dioxide
into organic matter as part of the global carbon cycle. Phytoplankton blooms
stimulate production of zooplankton, microscopic marine animals, which become a
food source for fish.
Mati Kahru, lead author of the study and a research oceanographer in
the Integrative Oceanography Division at Scripps, said it's not clear if the
consumers of phytoplankton are able to match the earlier blooms and avoid
disruptions of their critical life-cycle stages such as egg hatching and larvae
development.
"The spring bloom provides a major source of food for zooplankton,
fish and bottom-dwelling animals," he said. "The advancement of the
bloom time may have consequences for the Arctic ecosystem."
Such a match or mismatch in timing could explain much of the annual
variability of fish stocks in the region.
"The trend towards earlier phytoplankton blooms can expand into
other areas of the Arctic Ocean and impact the whole food chain," say the
authors, who used satellite data from 1997-2010 to create their bloom maps.
The NASA Ocean Biology and Biogeochemistry
Program and the National Science Foundation provided financial support for the
research. The satellite data were provided by the NASA Ocean Biology Processing
Group, ESA GlobColour group, the National Snow and Ice Data Center and the
Japan Aerospace Exploration Agency. Kahru's coauthors include Greg Mitchell, a
Scripps Oceanography research biologist, Vanda Brotas of the University of
Lisbon in Portugal and Marlenne Manzano-Sarabia of Universidad Autonoma de
Sinaloa in Mexico.
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