Ghosts in Glass: Ghost Crabs as Judges of Glass Sand for Coastal Restoration

Author

Emily Parrish, University of South AlabamaFollow

Date of Award

5-2025

Document Type

Undergraduate Thesis

Degree Name

BS

Department

Biology

Faculty Mentor

Jeremiah Henning

Advisor(s)

Jack O'Brien, Jonathan Perez

Abstract

Over 60% of the Gulf of Mexico coastline is actively eroding, which has resulted in thousands of miles of lost coastline over the last 100 years. This drastic loss of coastal land highlights the dire need for coastal restoration across the entirety of the Gulf Coast. A vital aspect of restoring these eroded areas is replenishing eroded substrate, traditionally conducted through offshore dredging of substrates which comes with high economic and ecological costs. Recycled glass sand may be able to fill this role and reduce our reliance on dredging while lowering the amount of glass waste entering landfills each year. Our goal is to determine whether glass sand is a viable option for coastal restoration by testing the impact on a critical indicator organism in coastal dune ecosystems, the Atlantic Ghost Crab, Ocypode quadrata. Live caught ghost crabs from Dauphin Island, Alabama were reared in mesocosms containing full beach sand, half beach sand and half glass sand, and full glass sand for 8 weeks. To compare the effect of glass sand substrate on crab morphology and physiology, we measured carapace widths, mass, claw dimensions and crab mortality, crustacean hyperglycemic hormone at time of collection and after 8 weeks. We found no significant main effects of substrate and a weak effect of sex on crab mortality. We found no significant difference in carapace width or change in total mass across substrate, or sex. We found an 18.5% greater change in dominant claw volume in beach sand compared to glass sand substrate; however, we did not see any differences between sexes. Though final analysis of CHH levels is ongoing, we were able to confirm that commercial ELISA kits can reliably detect CHH levels in Atlantic Ghost Crabs and that those levels can be spiked for more sensitive testing. Overall, our growth and survival data indicate that ghost crabs had similar responses in glass sand and beach sand, suggesting that glass sand may be a viable option for large-scale restoration efforts both locally and globally.

Comments

© 2025 Emily Parrish ALL RIGHTS RESERVED

Recommended Citation

Parrish, Emily, "Ghosts in Glass: Ghost Crabs as Judges of Glass Sand for Coastal Restoration" (2025). Honors Theses. 100.
https://jagworks.southalabama.edu/honors_college_theses/100