The Impact of Hydrologic State on CO2 flux and Acidification in Subtropical Estuaries

Principal Investigator

Led by Dr. Xinping Hu, HRI Chair for Ecosystem Science & Modeling, this project will integrate research and education to investigate air-water CO2 flux and acidification of estuarine waters. Fieldwork will be carried out in a highly dynamic subtropical estuary as a case study and will be coupled with the analysis of a multidecadal dataset from a broad expanse of subtropical coastal estuaries subject to strong hydrologic and climatic gradients.

Educational components of the project include:

  1. Creation of an ocean and estuarine acidification research course at Texas A&M University-Corpus Christi (TAMU-CC) that utilizes hands-on, inquiry-based group learning, as well as the redesigning of two existing courses at TAMU-CC based on the experience of this new course, and
  2. Collaboration with Foy Moody High School to engage ninth through twelfth grade students, predominantly from underrepresented and economically challenged backgrounds, in field and lab experiences that will enrich their educational curriculum while encouraging their involvement in current environmental issues pertinent to this project.

The ultimate educational goal is to encourage high school students to pursue a STEM (Science, Technology, Engineering, Math) path for their college education and for undergraduate STEM students to pursue graduate degrees.


Research objectives of the project include:

  1. Unraveling the relationship between hydrologic state and estuarine CO2 partial pressure (pCO2) in a case study of the Mission-Aransas Estuary,
  2. Understanding the extent of CO2 flux and its hydrologic control in one of the world’s largest lagoonal estuarine systems along the northwestern Gulf of Mexico, and
  3. Elucidating the mechanisms that lead to estuarine acidification and its feedback to CO2 fluxes.

Intensive field campaigns for high-temporal resolution pCO2 and water carbonate chemistry sampling as well as sediment incubation for benthic alkalinity consumption will be carried out. Analysis of multidecadal carbonate chemistry parameters will be used to obtain temporal trends of water pCO2 against the backdrop of increasing freshwater scarcity in this region.


This project runs October 2020 through April 2022. It was initially awarded when Dr. Hu served as faculty with the TAMU-CC College of Science and Engineering.