Nearshore Sediment Comparisons among Natural, Living, and Armored Shorelines in Mobile Bay, Alabama

Saranee Dutta¹, Patrick D. Biber^1,*, and Chris A. Boyd²

¹Gulf Coast Research Laboratory, School of Ocean Science and Engineering, The University of Southern Mississippi, 703 East Beach Drive, Ocean Springs, MS 39564. ²Department of Biological and Environmental Sciences, Troy University, Montgomery, AL 36103. *Corresponding author.

Southeastern Naturalist,Volume 20, Issue 1 (2021): 135–151

Abstract
This study was conducted to compare the sediment parameters of 2 project sites located near Dauphin Island, AL, which each contained a natural shoreline (NS), a living shoreline (LS), and a hardened shoreline (HS) treatment. We collected sediment core samples from the shallow intertidal zone along 3 replicate transects and sectioned them into shallow (0–15 cm) and deep (16–30 cm) fractions. We analyzed sediment subsamples for bulk density, sediment grain size, total carbon, total nitrogen, and extractable phosphorus. At both project sites, HS sediments contained significantly more sand (>90% percent) and higher bulk density than NS and LS sediments. The HS sediments also contained significantly less C and N than the LS and NS. These data suggest that LS treatments over time facilitate conditions that favor organic-matter rich and fine-grained sediments and approach the conditions found in the NS, in contrast to HS sediments that become less suitable for marsh development. These sediment changes in LS treatmnts promote habitat conditions that help facilitate marsh expansion and thereby provide important habitat for estuarine dependent wildlife.

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