Journal of Marine Science: Research & Development
Open Access

Abstract

Because of their limited temperature tolerance range (~18-28oC), corals face increasing threats from climate change/global warming. Will corals survive this perturbation, and, if so, how? We examined the distribution of oceanic climatic zones and developed a predictive model for future changes. The Equatorial Zone may be expected to expand, pushing the tropical, subtemperate, and temperate zones poleward. This movement will be at the expense of the shrinking sub-polar and polar zones. A Hyper-Tropical Zone may be expected to appear in the middle of the Equatorial Zone, which will possess the highest seawater temperatures of the Earth?s oceans, becoming a zone of local or global extinction. Examples of zooxanthellate organisms affected would include the scleractinian corals, soft corals, sponges, and giant clams. Zooxanthellar strains and species with broader temperature tolerances will ?migrate? poleward with the Equatorial and Tropical Zones. The probability of other symbionts such as cyanobacteria, Chlorella, or chloroplast units themselves becoming substitute symbionts is possible but highly improbable due to required adaptations in both host and symbiont and their immunological systems. Thus, some corals, zooxanthellar strains, and other zooxanthellate species will become extinct in the Hyper-Tropical Zone due to increasing seawater temperatures, while others will follow the migration of the Equatorial and Tropical Climatic Zones poleward. In the short-term, no new symbiotic arrangements will emerge between the ex-zooxanthellate hosts and new photosynthetic symbionts because of the rapidity of the climate change/global water and the lack of evolutionary time required to accommodate all of the adaptations required for such.

Biography

Paul W Sammarco is a Professor, Louisiana Universities Marine Consortium (LUMCON), Chauvin, Louisiana, USA. He has conducted research on coral reef ecology for 45 years in the Caribbean and Great Barrier Reef, Australia. He has >300 publications and has served as an Asst. Professor, Clarkson University (NY); Senior Research Scientist, Australian Institute of Marine Science; Executive Director, LUMCON; Director, Envtl. Research, Resource Assessment Commission, Dept. Prime Minister and Cabinet (Australia); Executive Director, Assn. Marine Laboratories Caribbean; Chairman, State Commission, South Louisiana Wetlands Discovery Center; Assoc. Editor, Marine Biology, Marine Ecology Progress Series, and Aquatic Biology. His PhD is in Ecology and Evolution.