The distribution of submarine groundwater discharge and its effect on coastal water quality in Mississippi

 
 

Principal Investigators: Adam Skarke (Mississippi State University), Alan Shiller (University of Southern Mississippi), Natasha Dimova (University of Alabama)

Team Members: Amy Moody (USM), Zachary Peoples (MSU), Stephen Anderson (UA), Riza Magbitang (USM), Jackson Stewart (UA), Shaily Rahman (USM), Kenneth Bolster (USM), Laura Whitmore (USM), Megan Hansen (USM)

Undergraduate Intern: Talon Washington (Deepwater Horizon Memorial Internship, USM), Megan Hansen (USM)

Award Amount: $450,052

Project Description

Goal:

Understand controls on the location, timing, and composition of submarine groundwater discharge (SGD) in Mississippi coastal waters

Why it is Important:

SGD transports nutrients, contaminants, and pathogens into coastal waters at concentrations comparable to surface waters, potentially contributing to eutrophication and hypoxia.

Objectives:

  • Geochemical sampling to analyze SGD composition

  • Geochemical tracer surveys to map spatial and temporal variability of SGD

  • Geophysical profile surveys to map presence of fresh groundwater and influence of geology on the location of SGD in Mississippi Sound

Expected Outcomes and Management Impacts:

  • Improved understanding of the contribution of SGD to nutrient budgets and water quality degradation in Mississippi coastal waters

  • Improved understanding of the contribution of anoxic SGD to hypoxia in Mississippi coastal waters

  • Improved understanding of seafloor locations where ecosystem stress due to poor water quality conditions and hypoxia are most likely to occur

  • Resulting maps of SGD “hotspots” can inform the evaluation of the suitability of seafloor locations as benthic habitat for oysters and optimize restoration actions like oyster cultch deployment

Project Outputs

    1. Gilbert M, Davis J, Moody A, Shiller A, “Utilizing water isotopes to differentiate Mississippi River, local rivers, and groundwater sources to the Mississippi Sound and Lake Pontchartrain area”, Bays & Bayous Symposium, Mobile, AL, January 24, 2023

    2. Moody A, Gilbert M, Shiller A, “Dissolved rhenium reveals freshwater sources to Mississippi Sound”, Bays & Bayous Symposium, Mobile, AL, January 24, 2023

    3. Moody A, Shiller A, “Seasonal Shifts in Groundwater Dominance in the Mississippi Sound.” Ocean Sciences Meeting (Virtual), February 24-March 4, 2022

    4. Peoples Z, Skarke A, “Characterization of Quaternary stratigraphy in the Mississippi Sound to evaluate the influence of geologic heterogeneity on submarine groundwater transport and discharge”, Ocean Sciences Meeting (Virtual), February 24-March 4, 2022

    5. Shiller A, Gilbert M, Moody A, Ho P, Joung DJ, Sanial V, “Use of stable isotopes to trace Mississippi River discharge in Louisiana and Mississippi coastal waters.” State of the Coast Conference (Virtual) June 3, 2021

    6. Moody A, Shiller A, Almario A, “Impact of submarine groundwater discharge (SGD) on the western Mississippi Sound.” Bays and Bayous Symposium (Virtual), December, 2020

    7. Moody A, Shiller A, “Multi-tracer approach to determine effects of submarine groundwater discharge on the Mississippi Sound.” American Geophysical Union Fall Meeting (Virtual), December, 2020.

    8. Moody A, Shiller A, Pierce T, Almario A, "Does submarine groundwater discharge play a role in seasonal hypoxia in the Mississippi Sound?" Ocean Sciences Meeting, San Diego, CA, February 2020.

    1. Amy Moody, 2022, “Evaluating the impact of submarine groundwater discharge on nutrients and trace elements in coastal systems: The examples of the Tuckean Swamp (Australia) and the Mississippi Sound (USA)”, University of Southern Mississippi Ph.D.

    2. Zachary Peoples, 2022, “Characterization of Quaternary stratigraphy in the Mississippi Sound to evaluate the influence of geologic heterogeneity on submarine groundwater transport and discharge”, Mississippi State University M.S. Thesis.

    1. Heal, E.N., Mize, S.V., Glisch, E., Frederick, P., Swarzenski, C.M., Loftin, K.A., St. Amand, A., Shiller, A.M., and Gilbert, M., 2023. Water-quality and phytoplankton data for Lake Pontchartrain and the western Mississippi Sound associated with operation of the Bonnet Carré Spillway, 2008–2020. U.S. Geological Survey data release, https://doi.org/10.5066/P9XE6KVW.W. (We contributed to an online USGS data release which includes water isotope data in Lake Pontchartrain and the western Mississippi Sound.)

    2. Moody, A., 2022. Global STE Nutrients. https://marineresearch.shinyapps.io/Gobal_STE_Nutrients/ (This is an open access online global compendium of nutrients in submarine estuaries [i.e., SGD], including a mapping tool.)

  • Moore, W.S., Benitez-Nelson, C., Schutte, C. et al. SGD-OD: investigating the potential oxygen demand of submarine groundwater discharge in coastal systems. Sci Rep 14, 9249 (2024). https://doi.org/10.1038/s41598-024-59229-7