EAPSI: The Effect of Increased Ocean Temperatures on Species Diversity in Cauliflower Corals (Pocillopora spp.)

Chan Andrea N, State College PA

Investigators

Abstract

Healthy coral ecosystems are beneficial to island nations, providing significant revenue from tourism and protecting their coastlines from erosion due to wave action and storms. In addition, coral reefs support a high diversity of other taxa, and thus maintaining coral ecosystems directly sustains marine biodiversity. Corals are sensitive to changes in their thermal environment, with sustained increases of a few degrees above the summer maximum causing their algal symbionts to leave their tissues (coral bleaching). Reef-building corals rely on these symbionts for a large proportion of their metabolic needs, and if temperatures remain elevated the corals perish. Recent studies have demonstrated the merit of using natural experiments to predict how climate change could affect reefs. Dr. Chaolun Allen Chen of Academia Sinica, has successfully used a high temperature reef site near the outlet of a nuclear power plant in Southern Taiwan to investigate the effects of chronic warm waters on juvenile cauliflower coral (Pocillopora spp.) diversity. This award supports research under Dr. Chen?s mentorship that builds on this work by examining the diversity of the adult cauliflower corals at two sites: one near the nuclear power plant and one farther away with normal water temperatures. For this natural experiment, tissue samples will be collected from both sites, and the mitochondrial open reading frame (ORF) will be sequenced. The ORF regions will be used in subsequent phylogenetic analyses, and the diversity between sites will be compared using standard biodiversity indices. If the relative proportion of Pocillopora species differs between the warm site and the normal temperature site, then this would indicate differential resilience to increased temperatures between species. An absence of significant differences in Pocillopora coral diversity between these sites would point to other mechanisms for maintaining physiological performance (e.g. gene expression, alternate algal symbionts, or microbiome differences). Because this coral genus is globally distributed, our findings will be useful for coral conservation beyond the boundaries of Taiwan. This NSF EAPSI award is funded in collaboration with the Ministry of Science and Technology of Taiwan.