title: Towards an Understanding of the Interactions between Freshwater Inflows and Phytoplankton Communities in a Subtropical Estuary in the Gulf of Mexico.
abstract: Subtropical estuaries worldwide face increased pressure on their ecosystem health and services due to increasing human population growth and associated land use/land cover changes, expansion of ports, and climate change. We investigated freshwater inflows (river discharge) and the physico-chemical characteristics of Galveston Bay (Texas, USA) as mechanisms driving variability in phytoplankton biomass and community composition between February 2008 and December 2009. Results of multivariate analyses (hierarchical cluster analysis, PERMANOVA, Mantel test, and nMDS ordination coupled to environmental vector fitting) revealed that temporal and spatial differences in phytoplankton community structure correlate to differences in hydrographic and water quality parameters. Spatially, phytoplankton biomass and community composition responded to nutrient loading from the San Jacinto River in the northwest region of the bay (consistent with nutrient limitation) while hydraulic displacement (and perhaps other processes) resulted in overall lower biomass in the Trinity River delta (northeast region). The influence of inflows on phytoplankton diminished along a north to south gradient in the bay. Temporally, temperature and variables associated with freshwater inflow (discharge volume, salinity, inorganic nitrogen and phosphorus concentrations) were major influences on phytoplankton dynamics. Dissolved inorganic nitrogen: phosphorus (DIN:DIP) ratios suggest that phytoplankton communities will be predominately nitrogen limited. Diatoms dominated during periods of moderate to high freshwater inflows in winter/spring and were more abundant in the upper bay while cyanobacteria dominated during summer/fall when inflow was low. Given the differential influences of freshwater inflow on the phytoplankton communities of Galveston Bay, alterations upstream (magnitude, timing, frequency) will likely have a profound effect on downstream ecological processes and corresponding ecosystem services.
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, Galveston, Texas, 77553, United States of America.
authors.forename: Samuel
authors.initials: S
authors.lastname: Dorado
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, Galveston, Texas, 77553, United States of America.
authors.forename: Tyra
authors.initials: T
authors.lastname: Booe
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, Galveston, Texas, 77553, United States of America; Department of Oceanography, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Jamie
authors.initials: J
authors.lastname: Steichen
authors.affiliation: Department of Oceanography, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Allison S
authors.initials: AS
authors.lastname: McInnes
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, Galveston, Texas, 77553, United States of America.
authors.forename: Rachel
authors.initials: R
authors.lastname: Windham
authors.affiliation: Department of Oceanography, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Alicia
authors.initials: A
authors.lastname: Shepard
authors.affiliation: Department of Oceanography, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Allyson E B
authors.initials: AE
authors.lastname: Lucchese
authors.affiliation: Department of Oceanography, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Hannah
authors.initials: H
authors.lastname: Preischel
authors.affiliation: Biological Sciences, University of South Carolina, Columbia, South Carolina, 29208, United States of America; Marine Science Program, University of South Carolina, Columbia, South Carolina, 29208, United States of America.
authors.forename: James L
authors.initials: JL
authors.lastname: Pinckney
authors.affiliation: Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas, 77843, United States of America; Everglades Foundation, Palmetto Bay, Florida, 33157, United States of America.
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Davis
authors.affiliation: Department of Oceanography, Texas A&M University, College Station, Texas, 77843, United States of America; Department of Wildlife and Fisheries Sciences, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Roelke
authors.affiliation: Department of Marine Biology, Texas A&M University at Galveston, Galveston, Texas, 77553, United States of America; Department of Oceanography, Texas A&M University, College Station, Texas, 77843, United States of America.
authors.forename: Antonietta
authors.initials: A
authors.lastname: Quigg
mesh_terms: D018533:Biomass; D000458:Cyanobacteria / Q000502:physiology*; D017377:Diatoms / Q000502:physiology*; D017753:Ecosystem; D063366:Estuaries; D060851:Gulf of America; D006801:Humans; D015999:Multivariate Analysis; D009584:Nitrogen / Q000172:deficiency*; D010758:Phosphorus / Q000378:metabolism; D010839:Phytoplankton / Q000502:physiology*; D011157:Population Dynamics; D045483:Rivers; D054712:Salinity; D012621:Seasons; D012623:Seawater; D013696:Temperature; D013781:Texas; D014329:Tropical Climate
chemical_list: D010758:Phosphorus; D009584:Nitrogen