Impacts of Freshwater on Ocean Acidification for Three Northwestern Gulf of Mexico Estuaries

Principal Investigator

Estuaries are known to be highly influenced by freshwater inflow. The northwestern Gulf of Mexico has a natural latitudinal gradient in amount of freshwater inflow available to estuaries. Estuaries in the northwestern Gulf of Mexico have demonstrated long-term (1970s to 2010s) declining pH and alkalinity. To investigate the long-term influence of river alkalinity input on estuary alkalinity inventory and biogeochemical processes’ influence on alkalinity changes, Dr. Xinping Hu, HRI Chair for Ecosystem Science & Modeling, and his team will:

  • Calculate annual alkalinity yield and flow-weighted alkalinity concentration.
  • Analyze spatiotemporal lag-time correlation analyses to elucidate relationships between alkalinity yield and estuarine alkalinity over multidecadal time periods.
  • Consider long-term trends and relationship with weather dynamics and freshwater diversions in the final analyses.
  • Consider influences on ecosystems and local fisheries.
  • Incubate sediments to examine the influence of biogeochemistry on alkalinity consumption for the Mission-Aransas Estuary.

Because little is known about carbonate systems of subtropical estuaries, Dr. Hu’s research stands to yield broad impacts. The research will clarify the relationship between river alkalinity yield and estuary pH and alkalinity for subtropical estuaries. Specifically, Texas estuaries exhibit a range of freshwater inflow conditions and results will extrapolate to a variety of subtropical estuaries with varying inflow. This research will clarify the interconnected influences of freshwater diversion, alterations in weathering patterns, and increases in atmospheric CO2 on estuarine acidification in the northwestern Gulf of Mexico and globally.