Term of Award
Fall 2025
Degree Name
Master of Science in Biology (M.S.)
Document Type and Release Option
Thesis (restricted to Georgia Southern)
Copyright Statement / License for Reuse
This work is licensed under a Creative Commons Attribution 4.0 License.
Department
Department of Biology
Committee Chair
Risa Cohen
Committee Member 1
Christine Hladik
Committee Member 2
Michele Guidone
Abstract
Sea level rise threatens coastal marsh stability; therefore, restoration techniques that increase marsh elevation to mitigate degradation are essential. In 2019, dredged sediment (15-25 cm) was placed onto a back-barrier marsh on Jekyll Island, Georgia. This thin layer placement (TLP) increased elevation, but introduced nonlocal sediment, potentially altering substrate composition and affecting benthic infauna. Infauna aid nutrient cycling and vary in disturbance tolerance, thereby serving as indicators of marsh recovery. I hypothesized that infaunal abundance, community composition, and sediment characteristics reflect disturbance from sediment addition. Sediment cores were collected from the TLP site (inside and outside the application area) and a control site in spring 2024 and 2025. Mean infaunal abundance was lower at the TLP site in both years, but increased from 2024 to 2025 at all sites, indicating temporal rather than spatial differences. Dominant taxa occurred in comparable proportions among sites in both years, demonstrating similar community composition. However, taxa contributing to dissimilarity varied between years but showed no consistent differences from sediment placement. Sediment characteristics were similar among sites, with salinity increasing between years and grain size changing over time without site-level differences. Although organic content was lower at the TLP site, it increased between years and remained within a range capable of supporting infauna. Similar sediment conditions and infaunal community structure demonstrated that the TLP site supports a functioning benthic community comparable to reference sites, suggesting recovery from TLP disturbance and supporting TLP as an effective method for maintaining marsh function under accelerating SLR.
Recommended Citation
Kilian, Samantha G., "Comparing Infaunal Communities and Sediment Characteristics Across Thin Layer Placement and Reference Sites at Jekyll Island, Georgia" (2025). College of Graduate Studies: Theses & Dissertations. 3059.
https://digitalcommons.georgiasouthern.edu/etd/3059
Research Data and Supplementary Material
No
