Towards an Understanding of the Interactions between Freshwater Inflows and Phytoplankton Communities in a Subtropical Estuary in the Gulf of Mexico

• DOI: 10.1371/journal.pone.0130931
• Publication Date: 2015-07-02T18:16:11Z
• Authors: Samuel Dorado; Tyra Booe; Jamie Steichen; Allison S. McInnes; Rachel Windham; Alicia Shepard; Allyson E. B. Luc...; Hannah Preischel; James L. Pinckney; Stephen E. Davis; Daniel L. Roelke; Antonietta Quigg
• Keywords: Freshwater inflow

Subtropical estuaries worldwide face increased pressure on their ecosystem health and services due to increasing human population growth associated land use/land cover changes, expansion of ports, climate change. We investigated freshwater inflows (river discharge) the physico-chemical characteristics Galveston Bay (Texas, USA) as mechanisms driving variability in phytoplankton biomass community composition between February 2008 December 2009. Results multivariate analyses (hierarchical cluster analysis, PERMANOVA, Mantel test, nMDS ordination coupled environmental vector fitting) revealed that temporal spatial differences structure correlate hydrographic water quality parameters. Spatially, responded nutrient loading from San Jacinto River northwest region bay (consistent with limitation) while hydraulic displacement (and perhaps other processes) resulted overall lower Trinity delta (northeast region). The influence diminished along a north south gradient bay. Temporally, temperature variables inflow (discharge volume, salinity, inorganic nitrogen phosphorus concentrations) were major influences dynamics. Dissolved nitrogen: (DIN:DIP) ratios suggest communities will be predominately limited. Diatoms dominated during periods moderate high winter/spring more abundant upper cyanobacteria summer/fall when was low. Given differential Bay, alterations upstream (magnitude, timing, frequency) likely have profound effect downstream ecological processes corresponding services.