Planning the future by exploring the past in Mississippi’s Grand Bay

People have harvested oysters in Mississippi’s Grand Bay for more than 4,000 years. Today, that legacy is at a crossroads. Increased pollution from residential and industrial development and overtaxed wastewater treatment systems is flowing into the Bay with potentially far-reaching effects on ecosystems, human health, and local economies. To protect human health and identify areas at risk for habitat degradation and fisheries loss, local decision-makers need more information about the extent of these impacts on local ecosystems. In response to this need, the Grand Bay reserve worked with Dauphin Island Sea Lab used Grand Bay as a benchmark estuary to define the legacy effects of land use change on water quality, historic and modern oyster populations, shifts in nitrogen sources, and pathogen accumulation.

Project Impact

This project is helping local and regional stakeholders understand the impacts of land use on environmental and human health, identify areas at risk for habitat degradation and fisheries loss, and reduce the risk of harvesting contaminated shellfish.

Municipal officials and wastewater treatment plant representatives have used project data to make decisions about operations at a wastewater treatment plant and demonstrated the efficacy of the plant at reducing fecal indicator microbes. Mississippi’s Utility Authority and the U.S. Food and Drug Administration used project data to evaluate the effects effluent from the plant on local shellfish beds. Additionally, eco-tour business to use project information to enhance naturalist tours in the Grand Bay area.

During the project, the team identified a phosphate spill, and team members shared project data with the Alabama Department of Environmental Management to address the spill’s environmental implications and identify future sampling and monitoring actions to minimize spill effects.

How it worked

A team from the Grand Bay reserve and Dauphin Island Sea Lab worked with the U.S. Food and Drug Administration, the University of Southern Mississippi, and coastal managers to investigate historic land use changes in Grand Bay and define the resulting effects on ecosystem and human health. To ensure that scientific outputs met the needs of decision-makers, the team engaged stakeholders in project’s design and held workshops to integrate stakeholder perspectives throughout the project.

To improve the accuracy of current shellfish area closures, team members sampled and analyzed water quality and local shellfish populations to determine the impact of wastewater treatment plant discharge. They also modeled historic land use change in Grand Bay to define time scales of change and provide context for the evaluation of ecosystem and human health data. To trace the impacts of land use-related nitrogen sources and pathogen changes over time, they analyzed historic oyster shell deposits for nitrogen content and sediment cores for carbon and nitrogen content, stable isotope ratios, and bacterial indicators of potential human health risk. To link the effects of changing nutrient sources and microbial concentrations to changes in oyster growth rates and survival, they measured internal growth patterns, stable isotopes, and microbial indicators in modern oysters. Ultimately, they were able to combine the data from land use models, sediment cores, modern sediment and water samples, and historic and living oyster shells to define the legacy effects of land-use change through time.

NERRA Collaboration Research Guide

Developing a budget for a collaborative project is challenging. Building in resources for adaptation of products and outcomes based on stakeholder input is a critical and often overlooked resource requirement. Learn more about the team’s experience with this challenge in our Collaborative Project Toolkit.

NERRA Collaboration Research Guide

Resources

This project developed tools and resources that researchers and coastal managers can use to leverage the nitrogen content of oyster shells to identify historic land use and understand its impacts on coastal ecosystems. These include:

  • Project overview
  • Final report. For more information, contact the NERRS Science Collaborative program manager at NOAA’s Office for Coastal Management.
  • Peer-reviewed journal article: Gong, C. and W. Wu. Effects of shadow, atmospheric correction and seasonal factors on the extraction of subpixel imperviousness using regression tree modeling. Submitted to Photogrammetric Engineering and Remote Sensing.