Willis, B. L., Page, C. A., Boyett, H. V., Dinsdale, E. A., Lonergan, C. M.

Towards an understanding of the role of temperature in patterns of coral disease prevalence on the Great Barrier Reef

2006

Transactions, American Geophysical Union

87 [36 Supplement]

N.A.

Diseases of coral reef organisms have been escalating globally in the past few decades and, while climate change is speculated to underlie these patterns, the role of temperature in the increasing incidence of coral disease is difficult to separate from a range of other potential stressors. Here we compare seasonal patterns of coral disease prevalence in the northern sector of the Great Barrier Reef (GBR) Marine Park between 2002 and 2005, as a first step in understanding the role of elevated temperature in the epidemiology of coral disease in the region. Overall, disease prevalence increased dramatically between winter and summer surveys in three dominant coral families on the GBR, increasing fifteen-fold in summer in acroporids, twelve-fold in faviids and doubling in pocilloporids. In particular, mean prevalence of three coral diseases increased significantly in summer surveys; skeletal eroding band increased more than two-fold, black band and other cyanobacterial infections more than three-fold and white syndrome more than fifty-fold in summer. In combination, results for these diseases suggest a link between seasonally high temperatures and disease incidence. In contrast, no seasonal pattern was detected in the prevalence of brown band disease over the three years and experimental studies found no impact of elevated temperatures on rates of progression across host colonies. We conclude that coral pathogens vary in their response to temperature within seasonal ranges on the Great Barrier Reef. However, given putative links between disease prevalence and elevated temperatures for the majority of diseases surveyed, plus current trends in global climate change and intensity of human-related activities that compound stress in corals, studies such as ours on the Great Barrier Reef are critical for establishing global baselines against which to judge whether background levels of coral disease are increasing.

Australia /Great Barrier Reef Marine Park (Qld.) /climatic changes /coral reef conservation /Anthropogenic factors

CSA Abstract