Studying the Health of Benthic Microalgae in Coastal Bays and Estuaries
By April Smith
Demands for freshwater resources in Texas watersheds are forecasted to increase steadily due to population and economic growth and associated requirements for drinking water and agricultural irrigation. As a result, freshwater inputs into coastal bays and estuaries will likely be reduced, leading to higher salinities of Texas estuaries.
Alyce Lee, a doctorate student at Texas A&M University in the Department of Oceanography, is researching the effects of light, nutrients and salinity on benthic microalgae (BMA) community structure and productivity. BMA are microscopic, filamentous photosynthetic plants that live in the upper few millimeters of sediment surface layers. They inhabit shallow water and intertidal systems where there is sufficient light and nutrients. BMA are considered major primary producers in estuarine and coastal environments, and play a vital role in the food web serving as a carbon source for higher trophic levels.
“The goal of my research is to provide a valuable tool for estuarine and ecosystem managers to use to determine the health of their system,” said Lee.
Lee has done two experiments to date, one on Galveston Island’s East Beach and one in the laboratory. Lee’s experiments are conducted using sediment cores and water samples taken from the bay, as well as laboratory-produced samples of varying salt concentrations. Lee is trying to show that a 25 percent increase in salinity will result in a significant shift in BMA community composition, resulting in a reduction of BMA biomass and primary production.
If the food quality or species composition of the BMA community is altered due to higher salinities, higher trophic levels could be negatively impacted. This could have significant implications on the tourism and fishing industries by ultimately resulting in lowered shrimp, oyster and fish yields.
“By examining the status of these organisms you obtain insights into ecosystem health,” said Lee. “BMA are good indicators of ecosystem health because they respond quickly to changes in their environment, whether negative or positive.”
“People need to realize life thrives in sandy areas and those areas are still extremely important for estuarine diversity,” said Dr. James Pinckney, Lee’s supervisor and assistant professor in the Department of Oceanography at Texas A&M University.
