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Plankton Bloom
Tue Feb 18, 2003
Listen in RealAudio 
They are not exactly dust bunnies and you won't find them under the sea bed, but dust clouds
from Asian deserts have triggered a bloom of phytoplankton -- minute algae and other sea
plants -- in the North Pacific Ocean. And they might have given us a clue to slowing global
warming. Hi, I'm Bryan Yeaton with The Weather Notebook's weekly segment on global climate
change.
Phytoplankton populations and their carbon-fixing productivity depend on several environmental
factors including sunlight, temperature and nutrients. But, many marine biologists believe a
lack of dissolved iron in ocean waters severely limits phytoplankton growth. That theory was
uniquely tested in 2001.
In April, NASA satellites tracked a major duststorm, from near China's Gobi Desert to the
North Pacific. The storm kicked up waves and deposited large quantities of iron-rich dust onto
the sea surface.
Fortunately, researchers from Lawrence Berkeley National Laboratory had just deployed two
carbon explorer floats in the area. These are instruments that measure carbon particles to
determine phytoplankton growth.
In the weeks following the duststorm, researchers noticed an immense biomass bloom in the
upper ocean waters. The phytoplankton had nearly doubled.
Phytoplankton ingest carbon dioxide during photosynthesis, thus removing it from the
atmosphere. Some scientists believe that one solution to the problem of excess atmospheric
carbon dioxide could be to fertilize the oceans with iron particles to stimulate phytoplankton
growth. But that could cause numerous other problems, like less sunlight reaching sub-surface
sea life. Oceanographer James Bishop cautions, "There's a huge amount of science left to be
done. We've only scratched the surface."
Our climate change series is supported by the New England Science Center Collaborative, and
the Roy A. Hunt Foundation.
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