A Hydrological Seesaw and its Effect on Alkalinity Dynamics in Estuaries Along a Climate Gradient

The main goal of this project is to learn how changes in freshwater conditions in shallow estuaries affect how much alkalinity, or acid-neutralizing capacity, the sediments produce or consume. It is hypothesized that a reduction in freshwater runoff will reduce alkalinity production in sediments via respirational processes that do not require oxygen; and during extreme drought, reduced compounds, for example reduced sulfur, produced from the above processes can be oxidized and generates acids.

This project will examine three estuaries along the northwestern Gulf of Mexico with different amounts of freshwater inputs. One of the estuaries that experiences large freshwater runoff changes will be studied in more detail. The objective is to unravel the connection between these changes and the buildup and breakdown of reduced sulfur in the sediments. Additionally, the impact of these processes on the alkalinity of the water column will be assessed. This study will measure water column alkalinity changes and benthic fluxes, examine sedimentary record for historical changes, and conduct modeling to tie field measurements together.

Researchers from both Texas A&M University-Corpus Christi and Texas A&M University at Galveston will work on this project.

The results of this study will shed light on the role of hydrological conditions in nearshore alkalinity production and consumption. The findings will also be applied to other coastal regions in the face of decline in freshwater runoff. In addition, the model developed in this project can be used in a wide variety of applications in coastal research and management.