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Released July 2, 2003


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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April 20, 2004 4:09 PM