Hurricanes that wreak havoc on humans are now believed
to nurture the growth of tiny phytoplankton, microscopic
vegetation that float on the ocean surface gobbling up
harmful carbon dioxide. This finding puts researchers one
step closer to a comprehensive understanding of the ocean's
carbon cycle, to knowing how organisms like phytoplankton
protect the Earth from global warming and to determining
what effect phytoplankton might have on climate.
The research is being led by Steven M. Babin, a
meteorologist at the Johns Hopkins University
Babin had spent much of his career studying the
atmosphere's influence on military radar systems. In 1998,
he became curious about vegetation growth that appeared
after Atlantic Coast hurricanes and started studying ocean
color data from the SeaWiFS instrument on NASA's SeaStar
satellite. Previous research on phytoplankton bloom was of
little help because it relied largely on sporadic,
incomplete data from ships.
Using the satellite data he looked at how plant life
changed after each of 13 North Atlantic hurricanes passed
through the North Atlantic's Sargasso Sea region from 1998
to 2001. Because phytoplankton contain most of the
chlorophyll in the ocean, he analyzed levels of
chlorophyll, the green pigment in plants, to determine the
extent of vegetation growth. He found that after a
hurricane there were increases in these chlorophyll levels
along the hurricane tracks and that these increases
persisted for two to three weeks after the storm had
"Some parts of the ocean are like deserts, and there
isn't enough food for many plants to grow," Babin says.
"The satellite evidence indicates that hurricanes stir up
the colder deep ocean water, bringing necessary nutrients
to the surface to feed the phytoplankton and, in the
process, push it toward the sunlight, causing it to bloom,"
The study found the physical makeup of a storm,
including its size, strength and forward speed, is directly
related to the amount of phytoplankton that blooms. Bigger
storms appear to cause larger phytoplankton blooms.
"Because 1998 was the first complete Atlantic hurricane
season observed by the SeaWiFS instrument, we first noticed
this effect in late 1998 after looking at hurricane
Bonnie," Babin says. "This effect of hurricanes on ocean
deserts has not been seen before. We believe it is the
first documented satellite observation of this
Phytoplankton are a key element in the ocean carbon
cycle of carbon dioxide absorption, storage and release to
the atmosphere. The tiny plants absorb carbon dioxide, a
heat-trapping greenhouse gas, and draw it down to the ocean
floor as a carbon form when the tiny plants die, keeping it
safely contained for hundreds of years.
Scientists are still trying to determine how much
carbon dioxide might be removed from such a process, and
Babin's study is a step in that direction. "Better
knowledge of the carbon cycle will improve our
understanding of global ecology and how climate change
might affect us," Babin says.
Detailed results of Babin's research appeared in the
March issue of the Journal of Geophysical Research-Oceans.
Study co-authors include Jim Carton, University of
Maryland, College Park; Tommy Dickey, Ocean Physics
Laboratory, University of California, Santa Barbara; and
Jerry Wiggert, Center for Coastal Physical Oceanography,
Old Dominion University.
For images and more information on this re-search, go