Coral Reef Evolution

Utilizing the evolutionary history of Coral Reefs: to go forward, we must look back

Demi Mills, School of Biological Sciences, University of Essex

With the future of coral reefs being uncertain, and 2015 set to experience the third global bleaching event with an El Niño predicted to rival that of 1998. The future of these highly biodiverse ecosystems is what researchers are rapidly attempting uncover. Piecing together, and unlocking mechanisms involved in a coral species plasticity to adapt and/or acclimatize, understanding how and why some species of coral are more resilient to stress and how coral reef systems on a local, regional and global scale are to respond to the current change in climate and threats are topics of interest to modern

Anthropogenic factors pose intensifying threats to marine ecosystems leading to potential extinctions. Knowledge of past extinction patterns is important for predicting the factors that will determine future extinction vulnerability. Investigating into extinction rates across marine genera over the past 23 million years by using paleontologically calibrated models to assess intrinsic risk- extinction risk; extinction risk, defined as the probability of a fossil taxon being classified as extinct on the basis of its similarity to other fossil taxa that went extinct over the same interval of time, to evaluate the vulnerabilities of extant marine taxa. The intrinsic risk refers to the paleontologically calibrated estimates of baseline vulnerability of modern taxa. Along with mapping the geographical distribution identifies coastal biogeographic provinces where fauna with high intrinsic risk are strongly affected by human activity or climate change. The regions are disproportionately in the tropics, giving an indication that these ecosystems are particularly vulnerable to future extinctions. Indicating that these regions might be of priority for conservation

Scleractinia have generated a focus of high interest, due to their ecological importance and current uncertainty of reef systems. Through phylogenetic analysis conducted on single gene sequences, and concatenated mitochondrial and nuclear data the origins of this species was analysed. Findings pushed the evolutionary origins of Scleractinan corals deep into the Paleozoic, bridging the gap between the Ordovician and Mesozoic Scleractinia. Although the molecular markers used may not be optimal for addressing the deep-divergence events, the data is largely consistent with molecular clock based analyses, however should be verified using a range of additional markers. Importantly the early origin of this coral implied by this study contributes to the debate on the future of corals. The findings implied the lineage itself has been through several dramatic climate changes in the last 450my. Resulting that the Scleractinia would appear less vulnerable than previously suggested (Stolarski et al., 2011). The implications of conducting this research contributes to predicting the survival of particular coral species, and with this predict how the structure of reef species could