| Comparisons of Harmful Algae from the Barataria and Atchafalaya Estuaries and Nearshore Waters |
NO PRESENTATION AVAILABLE
Nancy N. Rabalais(1), Wendy Morrison(1), Warren Mendenhall(1), Ling Ren(1), Nazan Atilla(1), and Quay Dortch(2)
nrabalais@lumcon.edu
(1) Louisiana Universities Marine Consortium, 8124 Hwy. 56, Chauvin, LA 70344
(2) National Oceanographic and Atmospheric Administration
Abstract
The LUMCON Phytoplankton Group has conducted surveys of harmful algae based on a list (updated from Dortch et al. 1999) for a decade, and has developed a reasonably good understanding of the HABs occurring in south Louisiana and some of the factors that may influence them. The HAB presence/absence/abundance differ with salinity, nutrient, and turbidity levels. In the fresher end member of the Barataria estuary, cyanobacteria are more likely to be present; these are known to produce toxins that are detectable in these waters. Field and experimental results have identified factors in changes in phytoplankton communities (including HABs) as a result of diverted Mississippi River water into the upper end of the Barataria estuary. In the higher salinity areas of the Barataria estuary the HAB community consists primarily of dinoflagellates, many of which are toxin producers, and a toxin producing diatom. Less is known of the HAB composition of the Atchafalaya estuary. In the offshore waters of these two estuaries there are many instances of harmful algal blooms, consisting primarily of dinoflagellates and diatoms.
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