Effects of nutrient distributions on phytoplankton in lower Laguna Madre : with particular reference to brown tide




Whitledge, Terry E., 1943-
Stockwell, Dean A.

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The appearance of a dense phytoplankton bloom of a brown tide algae in lower Laguna Madre during late 1990 greatly reduced water clarity and recreational sports fishing. A biological monitoring program was undertaken over a one year period, September 1994 to August 1995, to assess the distribution of nutrients and phytoplankton water quality parameters in lower Laguna Madre. Samples were collected at 21 locations during monthly surveys of hydrographic, nutrient and plant pigment parameters. The ambient growth rates of the phytoplankton and brown tide organisms were measured at 10 locations distributed throughout lower Laguna Madre with reference to areas of dominant circulation near the Gulf of Mexico passes, discharge of the Arroyo Colorado, and advective losses to the Land Cut. The relative abundance and distribution of the brown tide organism during the study period were assessed with regard to inflows and discharges within the lower Laguna Madre. A special effort was continued in the Harlingen Ship Channel with respect to freshwater inflows and shrimp mariculture facilities.
September 1995
For Texas General Land Office, Coastal Division