Poster Presentation Society for Freshwater Science 2025 Annual Meeting

Dissolved oxygen dynamics of geographically isolated wetlands in southwest Georgia influenced by Hurricane Helene  (118742)

Jewell L Johnson 1 , Jamie L Rogers 2 , Chloe G.A. Hall 2 , Nicholas S Marzolf 2 , Jewell Johnson 1
  1. NSF Woods to Water RaMP Program, Tuscaloosa, AL, United States
  2. Aquatic Sciences, The Jones Center at Ichauway , Newton , GA, United States

Geographically isolated wetlands (GIWs) are common across the karst depressional landscape of the Dougherty Plain, southwest Georgia. GIWs are dynamic systems that include marshes, savannahs and swamps. Despite their small size relative to the surrounding landscape, GIWs provide many ecosystem services and are biogeochemical hotspots. Patterns of dissolved oxygen (DO) concentrations in inundated conditions inform biological activity, biogeochemical cycling, and greenhouse gas production. Understanding how DO changes at varying temporal scales (e.g., daily and seasonally), and different water levels can help inform habitat quality and ecosystem production. Additionally, changes in DO during and after storm events can inform ecosystem oxygen demand and system recovery.  Our study objective was to 1) understand how DO patterns vary across temporal scales and hydroperiods of GIWs and 2) determine how these are influenced by storm events. We collected continuous DO, climate, and precipitation data from four wetlands (two marsh savannahs and two Cypress swamps) at The Jones Center at Ichauway from July to November 2024. This period included Hurricane Helene, a 101-mm storm event across the Dougherty Plain between September 24 – 26th 2024. During the storm, we observed increased DO across all GIWs. Our results show greater diel DO variability in the marsh GIWs compared to the Cypress swamps. Knowledge of the influence that storm events have on wetland biogeochemistry is necessary for the agencies making informed decisions about greenhouse gas emissions and land management.