Consequences of Coral Bleaching for Sessile Reef Organisms

Abstract

The consequences of coral bleaching for reef corals, growth, productivity, and biodiversity are reviewed. Coral taxa are differentially affected by temperature stresses, and the complexities of their life histories make gross generalizations about impacts difficult. Some impacts, such as lost cover, reproduction, and recruitment, are highly visible and immediate, while others, such as changing species composition and reef calcification, are difficult to detect and unfold over longer timescales. Background water temperatures, light, water flow and water quality, as well as habitat also influence and interact with taxa to increase the complexity of responses. Additionally, some taxa appear to be changing their responses over time as locations are exposed to repeated stressful events. Diseases that frequently follow bleaching can be large scale and devastating in some regions, most notably the Caribbean. All the above factors continue to interact and are creating novel coral species assemblages increasingly composed of species with stress-resistant and weedy life histories. Increasing thermal stress is also associated with losses in coral cover through other mechanisms (i.e., diseases) but also the disappearance of growing and functioning reefs in many locations. Fisheries management has some potential to improve recovery rates of corals, but there is no evidence that management increases resistance to thermal stress, which is more dependent on local environmental conditions and the acclimation potential of coral species. Recommended fisheries restrictions differ in the Caribbean and western Indian Ocean with reduced line fishing recommended in the Indian Ocean and reduced trap fishing in the Caribbean. Differences are due to unique food web configurations, which further emphasizes understanding the local and ecological contexts when predicting and managing coral responses in a changing marine environment.