Date of Award

2015

Document Type

Thesis

Department

Environmental and Forest Biology

Thesis Advisor

Mark Teece

Keywords

Dutch Caribbean, Bari Reef, Kralendijk, physiological stress, human impacts, reef degradation

Abstract

Pathogen-host relation dynamics have adjusted in the Caribbean due to increased epizootic events and decreased coral cover resulting from anthropogenic influences. Reef-building corals are being infected by numerous diseases including dark spots disease, a ubiquitous Caribbean disease of an unknown agent. The objectives of this study were to quantify the change in dark spots disease prevalence in Siderastrea siderea and Stephanocoenia spp. from 1998 to 2014 and determine influencing conditions on prevalence and infection severity of disease. The abundance of benthic organisms and substrate types were also quantified. A 1350 m2 area between six sites on Bonaire was surveyed using belt and video transects to determine disease prevalence and benthic composition. Prevalence was compared temporally (1998 study to 2014 study) and spatially (Bonaire to Turks & Caicos, Grenada, and Bahamas). I found an increase in disease prevalence between 1998 and 2014 and moderate spatial variation between island sites. Site, colony size, spatial distribution, or coral density did not influence disease prevalence or infection severity of the disease. Substrate types varied between sites with live hard coral cover and sand and rubble cover. As dark spots disease did not have a positive correlation between coral density and prevalence, DSD does not follow a density- dependent model. Dark spots disease in these coral species most likely arises from opportunistic pathogens emerging from stressful environmental conditions due to lack of density- dependence. With the changing environment induced by anthropogenic consequences, it is prudent to monitor and quantify the status of reefs in terms of disease prevalence and its disease associated factors.

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