Identifier

etd-07132014-152427

Degree

Master of Science (MS)

Department

Biological Sciences

Document Type

Thesis

Abstract

Oyster reefs in the Gulf of Mexico provide water quality enhancement, shoreline stabilization, carbon sequestration, and facilitate spat recruitment. They are also essential refuges for numerous resident fish and invertebrates, in turn supporting commercial fisheries. Oyster reefs are however in danger worldwide as oyster fisheries increase and pollution from oil spills, such as the Deepwater Horizon spill further degrade reefs. The development of artificial reefs has therefore become a necessity. This study assesses both the long-term and acute response of oyster reef commensal communities to hydrocarbon contamination, as well as comparing the efficacy of artificial reef substrates for restoring these faunal assemblages. Long-term effects were analyzed by quantifying commensal abundance, taxa richness, and diversity from cultch-filled bags deployed at two sites in Barataria Bay, Louisiana, that experienced oiling from Deepwater Horizon, and two control sites. Bags were deployed seasonally in both 2012 and 2013, and the results indicated that while commensal abundance was generally greater at oiled sites, the effects of hydrocarbon contamination several years post spill were neither large nor consistent. To observe the acute colonization response, oil-soaked and control bags were retrieved 1, 2, 4, and 8 weeks after deployment at Grand Isle, LA, an area in Barataria Bay where no oil contamination was documented, in both June and September 2013. Oil effects on commensal communities were inconsistent and minimal by week 8, perhaps due to biodegradation of the hydrocarbons. Commensal communities were also sampled from bags containing either disarticulated oyster shell, limestone rubble or a composite material known as OysterCrete. While OysterCrete had the greatest abundance of commensal organisms, the experiments indicated that seasonal variation was more influential for commensal community dynamics, as well as new spat recruitment and growth, than the presence of hydrocarbons or various substrates. In areas in close proximity to major oil operations, such as the northern Gulf of Mexico, any restoration efforts that provide a hard substrate will be beneficial for the recruitment of commensal organisms if natural oyster reefs are impacted by anthropogenic disturbances.

Date

2014

Document Availability at the Time of Submission

Student has submitted appropriate documentation to restrict access to LSU for 365 days after which the document will be released for worldwide access.

Committee Chair

Brown, Kenneth

DOI

10.31390/gradschool_theses.3125

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