Area Groups to Collaborate on Coastal Dune Lakes Study

The Choctawhatchee Basin Alliance, Mattie Kelly Environmental Institute of Northwest Florida State College, Topsail Hill Preserve State Park and the University of Florida will be supporting a University of Florida Water and Soil Science graduate student, Brandy Foley, and her thesis research project focused on three coastal dune lakes in Walton County.

There are 15 recognized coastal dune lake formations along the Northwest Florida in Walton and Bay County. The Florida Natural Areas Inventory lists the coastal dune lakes of Northwest Florida as imperiled globally and vulnerable to extinction.

These formations are shallow, irregular shaped lakes which can periodically connect to the Gulf of Mexico, exchanging saltwater and creating periodic brackish water system. Their connection to the Gulf, known as the lake outlet, is intermittent and causing hydrologic conditions to fluctuate from fresh to saltwater conditions. The coastal dune lakes contain rich, biodiverse ecosystems that contain a species native to both fresh and saltwater conditions.

The outfall of Western Lake, the coastal dune lake found within Grayton Beach State Park. Photo by Nic Stoltzfus.

Coastal dune lake formations can be found in a few places around the world, most famously in Australia and New Zealand. However, the coastal dune lakes in Northwest Florida are unique from other locations due to the local geology, water chemistry and intermittent connection to the Gulf of Mexico.

The Sediment analysis thesis research project began on May 4 and 5, 2017, and consists of nine sediment core collections from two coastal dune lakes: Big Redfish and Eastern Lake.

Ms. Foley’s thesis research will analyze sediment cores for diatom species. Diatoms are the primary producers of ecosystems and are good indicators of environmental change. Identification of these species will provide the diatom population abundance for each lake. A total of three sediment cores will be collected and analyzed from each lake. The sediment cores will be radiocarbon dated to provide a timeline for the reconstruction of historical diatom populations in the lakes. Each diatom species has a preference to phosphorus-nutrient concentrations within the water, meaning that some diatoms prefer phosphorus-nutrient rich waters while others prefer nutrient poor conditions.

After establishing the diatom abundance and diatom-phosphorus preference data, a statistical analysis will be applied to reconstruct a chronological timeline of phosphorus-nutrient concentrations within the lakes. This data will provide the historical baseline conditions of the coastal dune lakes and allow for the assessment of nutrient influences to the lakes overtime.

This research has never been conducted on the Walton County Coastal Dune Lakes and could be pivotal to the future of these lakes.

Foley believes the research results can provide valuable insight to coastal dune lake functions and help determine environment changes that have impacted the lakes over time.

Furthermore, it could assist management agencies in evaluating and managing impacts to the coastal dune lakes.

The Mattie Kelly Environmental Institute, University of Florida, Topsail Hill Preserve State Park, Sanctuary at Redfish and Newman Dailey Resort Properties have all collaborated to fulfill the Choctawhatchee Basin Alliances coastal dune lake research initiative and support Ms. Foley’s study on’ three coastal dune lakes.

The Alliance has created partnerships with local and statewide entities to develop and support research on the coastal dune lakes in an effort to improve the comprehensive understanding of these unique ecosystems.

Choctawhatchee Basin Alliance is a non-profit organization responsible for improving the health of local waterways through monitoring, education, restoration, and research. For 20 years, CBA has promoted water stewardship within the Choctawhatchee watershed, growing the network of supporters who join in CBA’s mission to provide a future for these precious, natural resources.

For more info, visit Choctawhatchee Basin Alliance.