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STENNIS
SPACE CENTER
- Researchers from The University of Southern Mississippi Department
of Marine Science are working with a national team of scientists
to unravel the riddle of "red tides," or harmful algal
blooms.
Harmful algal
blooms are a particular form of microscopic marine plant life, or
phytoplankton, that accumulate and can have serious side effects
for surrounding organisms and, in some cases, humans. One form of
harmful algal bloom, a "red tide," occurs with frequency
along the west coast of Florida. These phenomena have been responsible
for large fish kills, and illnesses in marine mammals and humans.
Dr. Steven
Lohrenz and Dr. Donald Redalje, professors with the Southern Miss
Department of Marine Science at Stennis Space Center, are investigators
in the ECOHAB: FLORIDA project. They are working with colleagues
from the Florida Marine Research Institute, Mote Marine Laboratory,
the National Oceanic and Atmospheric Administration (NOAA), the
Environmental Protection Agency (EPA), North Carolina State University,
University of South Florida, Rutgers University, and the U.S. Department
of Agriculture.
Funded by various
government agencies, each organization in this five-year scientific
effort is studying different aspects of harmful algal blooms in
an attempt to answer a growing list of questions. What causes them?
How can they sustain life at such high densities in coastal waters?
How do they access nutrients for growth? How can we better detect
and monitor them?
"The more
we know about harmful algal blooms, the more questions we develop,"
Redalje said. With a generational lifecycle of about two to seven
days, the algae maintain extremely high densities in the blooms.
Redalje noted that his research has shown densities of between 700,000
and over 2 million cells per milliliter of ocean water.
"When
you consider that a milliliter is about the size of a sugar cube,
that's a lot of cells," he said.
Southern Miss'
participation in the ECOHAB: FLORIDA project has provided opportunities
for marine science graduate students to participate in thesis and
dissertation research. Students Xuemei Bai and Megan Natter have
been working to develop a more complete picture of the algae physiology
and why it can become so toxic.
"The algae's
physiology has to change to cause the blooms to reproduce,"
Natter said. So far, Natter has collected algal samples and is incubating
them in the laboratory setting to study the various compounds in
the algae, how they change over time and to compare these results
with what she has found using samples from blooms off the Florida
coast. Proteins, polysaccharides and lipids in the algae will be
closely studied to detect these changes.
Bai is studying
the vertical migration of the algae based on their chemistry. She
said she hopes her research will provide a better understanding
of the relationship between the physiological and biochemical state
of harmful algal blooms and its migratory behavior. "The findings
will be helpful for developing predictive models of migration behavior
and its regulation by environmental variables," Bai said.
The more we
know about harmful algal blooms, the more likely we will be able
to find methods of predicting or perhaps preventing them, Redalje
said.
Lohrenz is
contributing to efforts to refine methods of detection and, eventually,
develop large-scale models for predicting harmful algal blooms.
"We're
working to refine methods to detect and monitor optical properties
of the harmful algal blooms," said Lohrenz. One goal is to
collect data for the construction of a computer model to predict
the initiation, maintenance and dispersal of red tide on the west
coast of Florida.
By studying
the optical properties of the algae, researchers can hopefully devise
a method of spotting and tracking the blooms from airplanes or satellites.
This will give them information from which to predict their occurrence.
Doctoral student
Kevin Mahoney assisted Lohrenz in his research and has successfully
defended a dissertation on their work. Mahoney is now on his way
to do post-doctoral work at the Monterey Bay Aquarium Research Institute
in Moss Landing, Calif.
The ECOHAB:
FLORIDA project is due to be completed this year. Lohrenz and Redalje,
along with other researchers, will compile their notes into manuscripts
to be published in the Journal of Marine Systems.
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