Date of Award
12-2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Biological Sciences
Committee Chair/Advisor
Michael Childress
Committee Member
Kyle Barrett
Committee Member
Elizabeth Baldwin
Committee Member
Antonio Baeza
Abstract
The Florida Keys reef tract has rapidly shifted from a structurally complex, hard coral-dominated reef to a less rugose, soft coral-dominated reef. Persistent anthropogenic stressors facilitate ecological transitions by including recreational and commercial fishing and increased anthropogenic marine debris. These artificial structures are becoming habitats for small marine taxa known as cryptofauna. Cryptofauna are among the most essential yet understudied reef taxa where little is known about their fate considering degrading coral reefs and increasing anthropogenic disturbance. With increased anthropogenic stressors on the marine environment, the SCUBA diving community has initiated extensive marine debris removal efforts to assist in cleaning the seafloor. However, debris-species interactions complicate the motivations and intensity of debris removal. The current study took a four-step approach to study these interactions, assess cleaning behaviors by divers, and the impacts made on displaced marine organisms.
The first step involved a benthic cover census to identify substrate and marine debris composition for 30 reefs in the middle Florida Keys. Inshore reefs containing higher rugosity and coral cover also contained high densities of monofilament and rope. Plastic items overall contained the highest associated taxa diversity. Secondly, mobile cryptofauna communities were observed to determine differences between naturally occurring populations and those occurring on marine debris. Invertebrate diversity was measured using Autonomous reef monitoring systems (ARMS) on 14 patch reefs along the Middle Florida Keys Reef Tract. ARMS were used as a proxy for natural structure to compare to marine debris removed from the same reef locations. Each structural unit contained significantly different and diverse communities. Functional richness increased with taxa richness for ARMS communities, and debris-associated communities showed decreasing functional richness and high functional similarity, suggesting a specialization of debris-specific taxa.
Third, human impact was assessed using a mixed-methods approach to determine the factors affecting debris removal decisions and how these decisions affect debris clean-up efficiency in the SCUBA diving community. A gamified survey and interviews were used to determine what types of items divers would not remove and why and how dive professionals perceive their relationship with the ocean, marine debris, practitioners, and volunteers. Perceptions of risk to nature and risk to humans most impacted debris selections from the questionnaire, while dive professionals expressed sentiments towards ecological belonging, regulation compliance, business management, dive training, awareness, and risk assessments as factors influencing cleaning behavior. Lastly, we dove beyond perception to assess physical impact by measuring marine taxa diversity and biomass displaced during marine debris removals. Displaced taxa were observed from marine debris removed from the seafloor for eighteen dive events. Taxonomic groups most impacted resulted in Mithracidae crabs, Polychaete worms, and Scleractinia corals, representing over 58% of all taxa retrieved from marine debris. Using length-weight relationships, we estimated an impact of less than one kilogram of cryptofauna per debris removal dive.
These data suggest that there is 1) differential use of marine debris by associated biota, 2) associated biota are functionally similar, 3) debris removal regulations should continue to encourage education and awareness, and 4) understanding displacement impacts on marine cryptofauna will help to better understand reef health. This dissertation adds to the limited knowledge known about the use of marine debris by marine organisms and aims to aid in awareness which future marine debris management and innovations can use to conserve and maintain ecosystem function.
Recommended Citation
Payton, Tokea, "Socio-Ecological Drivers of Anthropogenic Marine Debris Effects on Coral Reef Communities in the Florida Keys, USA" (2024). All Dissertations. 3786.
https://open.clemson.edu/all_dissertations/3786
Author ORCID Identifier
0000-0002-1196-2024
