TY - JOUR
T1 - Towards an understanding of the interactions between freshwater inflows and phytoplankton communities in a subtropical estuary in the Gulf of Mexico
AU - Dorado, Samuel
AU - Booe, Tyra
AU - Steichen, Jamie
AU - McInnes, Allison S.
AU - Windham, Rachel
AU - Shepard, Alicia
AU - Lucchese, Allyson E.B.
AU - Preischel, Hannah
AU - Pinckney, James L.
AU - Davis, Stephen E.
AU - Roelke, Daniel L.
AU - Quigg, Antonietta
N1 - Funding Information:
This research was supported by grants from Texas Sea Grant (NA06OAR4170076), Texas Water Development Board (0904830894 and 1004831016), the Texas Commission for Environmental Quality (CE-00F208-01-0) and the Coastal Coordination Council under NOAA (NA08NOS4190458). The views expressed herein are those of the authors and do not necessarily reflect the views of the funding agencies or their staff. Many people from the Phytoplankton Dynamics Laboratory at TAMUG contributed to the successful completion of this project, Kung-Jen Liu (Calvin) from TAMU helped with nutrient analyses, and the following provided insightful and stimulating conversations: Jim Lester (HARC), Lisa Gonzalez (HARC), Ruben Solis (TWDB), Carla Guthrie (TWDB), George Guillen (UHCL) and Steven Johnston (GBEP). This paper is dedicated to Sammy Ray (1919–2013) and Charlotte Ray (1920–2014) who inspired a new generation to be passionate about all things related to freshwater inflows and the oysters they nourished. We thank the two reviewers and the editor for their careful reading of the manuscript before publication.
Publisher Copyright:
© 2015 Dorado et al.
PY - 2015/7/2
Y1 - 2015/7/2
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=84940055552&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0130931
DO - 10.1371/journal.pone.0130931
M3 - Article
C2 - 26133991
AN - SCOPUS:84940055552
SN - 1932-6203
VL - 10
JO - PLoS One
JF - PLoS One
IS - 7
M1 - e0130931
ER -
