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NSF PR 97-47 - June 25, 1997
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Breakthrough Research on Ocean Algae Could Lead to
Freeze- and Drought-Resistant Crops
"The missing link" has been found in how tiny ocean
algae produce a chemical substance that influences
cloud formation in the atmosphere.
The breakthrough research by a National Science Foundation
(NSF)-funded scientist at the University of Florida
at Gainesville could help explain global climate changes
and make it possible to develop agricultural crops
that resist freeze, drought and salt-water damage.
Andrew Hanson, a plant biochemist and molecular biologist,
describes his research in the June 26 issue of the
journal Nature. There, he identifies
the four steps by which marine algae make DMSP. Hanson
explains how marine algae produce DMSP (dimethylsulfoniopropionate),
which is converted into DMS (dimethylsulfide),
a sulfur gas that helps clouds form in the atmosphere.
For the first time, scientists now understand the
precise mechanism by which algae make DMSP. Researchers
have been interested in unraveling the mysteries of
DMSP for more than 30 years.
"This work furthers our understanding of the biological
origin of atmospheric dimethylsulfide, which is a
significant factor in the global sulfur cycle and
may play an important role in climate regulation,"
said Porter Ridley, program director in NSF's metabolic
biochemistry program.
"We have established the biochemistry of how algae
convert the common compound methionine -- which
is found in all algae -- into DMSP," Hanson explained.
Algae produce DMSP to protect themselves from the
negative effects of high salinity and freezing. DMSP
is also formed in some higher plants that are tolerant
to drought, freeze and salt stress, according to Hanson.
"If we can use genetic engineering to transfer the
capacity to make this compound from these simple marine
organisms into commercial agricultural crops, we should
be able to confer a useful degree of drought, freeze
and salt tolerance to these plants," Hanson said.
"Citrus, for example, would be a particularly good
target because it is quite sensitive to freezing and
has no DMSP or any related compounds itself."
"We also now have a clearer picture of how marine
algae help control world climate," Hanson said. "Since
DMS gas from algae is linked to cloud formation, its
role in global heating and cooling could be critical.
We don't know how future trends in world climate will
affect marine algae, but we do know there is a feedback
effect operating."
When the DMS sulfur gas in ocean water enters the
atmosphere by sea-air exchange, the gas is oxidized
into sulfuric acid. Tiny sulfuric acid particles then
help promote the formation of clouds which block and
reflect heat energy from the sun back into space,
resulting in a cooling effect on the earth.
Hanson is not, however, able to predict whether or
not global warming will have an impact on marine algae's
ability to make more or less DMS, which would affect
cloud formation.
Most of the algae used in Hanson's research were collected
along the east coast of Florida in Flagler County.
Editors: Photos are available by calling Thomas
Wright in Gainesville at: (352) 392-1773.
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