Liu, H. Marine Science Institute, University of Texas at Austin, hongbin@utmsi.utexas.edu
Buskey, E. Marine Science Institute, University of Texas at Austin, buskey@utmsi.utexas.edu

 
THE EFFECT OF HYPERSALINITY TO THE EXTRACELLULAR POLYMERIC SUBSTANCE (EPS) EXUDATION OF TEXAS BROWN TIDE ALGA, AUREOUMBRA LAGUNENSIS
 
The Texas brown tide alga, Aureoumbra lagunensis, produces large amounts of extracellular polymeric substance (EPS) that may protect them from being grazed by microzooplankton. The amount of the exudate appears to be dependent on the age of the cells and the nutrient conditions and physical characteristics of seawater. Laboratory experiments with batch cultures showed that both EPS and dissolved and particulate carbohydrate increased as the cultures go from exponential growth phase to stationary phase to declining phase. Per cell EPS and particulate carbohydrate concentration were more than 5 times higher during decline phase than that in exponential growth phase, whereas the difference for dissolved carbohydrate was much less. This indicates that the thick EPS layer surrounding A. lagunensis cells was developed when the population reached stationary and decline stages. The amount of carbohydrate and EPS produced per cells were significantly increased at higher salinity. The effects of nutrient conditions and bacteria on the production of EPS by A. lagunensis are currently underway. Our study may lead us to resolve the mystery of why the brown tide bloom had persisted in Laguna Madre, an often hypersaline coastal lagoon, for the past 7 years.
 
Day: Friday, Feb. 5
Time: 02:30 - 02:45pm
Location: Eldorado Hotel
 
Code: SS42FR0230E