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Phytoplankton Community Structure, Biomass and Diversity on the Louisiana Continental Shelf
Citation:
Kurtz, Jan, M. Murrell, J. Lehrter, AND B. Schaeffer. Phytoplankton Community Structure, Biomass and Diversity on the Louisiana Continental Shelf. Presented at ASLO 2013 Aquatic Sciences Meeting, February 17 - 22, 2013.
Impact/Purpose:
Coupled water-quality/phytoplankton community data may allow for improvements to models and more accurate predictions of the linkages between freshwater flow, nutrient loading and the timing and extent of hypoxia on the LCS.
Description:
Phytoplankton communities on the Louisiana continental shelf (LCS) respond to nutrient loading from the Mississippi and Atchafalaya River Basin (MARB). Enhanced phytoplankton biomass is a source of organic matter contributing to the development of seasonal hypoxia. Samples were collected during spring and fall of 2003 and 2005, when average MARB discharge was higher during the spring cruises (26 and 34 x 103 m3 s-1) compared to fall discharges (9.6 and 17 x 103 m3 s-1). In the months preceding the spring 2005 cruise, average discharge was particularly high (38 x 103 m3 s-1) along with nutrient load. Diatoms dominated phytoplankton communities in both seasons, accounting for 64-97% of numerical abundance and 73-98% of total biovolume in surface samples. Phytoplankton community abundance and biovolume were positively correlated with total nitrogen, particulate carbon, and dissolved carbon, but negatively correlated with salinity. Coupled water-quality/phytoplankton community data may allow for improvements to models and more accurate predictions of the linkages between freshwater flow, nutrient loading and the timing and extent of hypoxia on the LCS.