ORCID ID

0009-0002-2786-1735

Date of Award

8-2025

Degree Type

Dissertation

Degree Name

Ph.D.

Degree Program

Integrative Biology

Department

Biological Sciences

Major Professor

T. Eric Cox

Abstract

Artificial reefs are deployed to enhance marine habitats and fisheries, yet their role in supporting secondary production and their vulnerability to climate stressors remain understudied. This dissertation investigates the trophic ecology and climate sensitivity of benthic invertebrates at artificial reefs in the northern Gulf of Mexico. Chapter 1 assessed reef food webs using stable isotopes from fishes, invertebrates, and primary producers across six reefs and two seasons. Mixing models showed that most fishes rely on benthic reef carbon, while suspension feeders consume plankton and sediment microphytobenthos. Isotopic niche analysis revealed functional diversity and seasonal shifts in δ¹³C and δ³⁴S, though niche widths remained stable. Chapter 2 examined the effects of ocean warming (OW) and acidification (OA) on the suspension-feeding clam Chama macerophylla. Single stressors increased metabolism, while combined OW and OA (OWA) reduced it. Warming also reduced tissue biomass relative to shell weight, suggesting energetic trade-offs. Chapter 3 expanded vulnerability assessments to two additional invertebrates—Megabalanus coccopoma (barnacle) and Stenorhynchus seticornis (arrow crab)—and evaluated predation risk by Gray Triggerfish (Balistes capriscus). M. coccopoma survival declined under extreme OW and OWA; S. seticornis experienced total mortality at the highest temperatures and increased predation under OWA. Overall, this work shows that artificial reefs support trophic linkages but host invertebrate species critical to ecosystem function that are vulnerable to climate change. These findings emphasize the importance of considering species-specific thresholds to avoid prey loss, disrupted predator-prey interactions, and reduced reef functionality in a changing ocean.

Rights

The University of New Orleans and its agents retain the non-exclusive license to archive and make accessible this dissertation or thesis in whole or in part in all forms of media, now or hereafter known. The author retains all other ownership rights to the copyright of the thesis or dissertation.

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