Response of estuarine phytoplankton to nutrient and spatio-temporal pattern of physico-chemical water quality parameters in Little Vermilion Bay, Louisiana

We studied the response pattern of phytoplankton to nutrient concentrations in Little Vermilion Bay, Louisiana in July and November 2013. It is important to understand the response of phytoplankton to nutrient concentrations in order to find impacts of eutrophication and improve the water quality for survival of fish and other aquatic life. Total Nitrogen and Total Phosphorus were measured in Little Vermillion Bay at several sampling locations along with some other water quality parameters and response of phytoplankton biomass was evaluated. The spatial-temporal pattern of water quality parameters in the study area was assessed using a spatial interpolation method. Phytoplankton biomass was positively correlated with nutrient enrichment in Little Vermillion Bay. Chlorophyll a concentrations were found to be strongly dependent on Total Nitrogen and Total Phosphorus in the water column. Nutrient concentration in the water column has a strong control over phytoplankton biomass and primary production. The TN:TP ratio was evaluated to establish the limiting nutrient for eutrophication in the study area. Both nitrogen and phosphorus were found to have strong relationships with phytoplankton growth and a growth limiting nutrient was not established for Little Vermilion Bay.