The molecular ecophysiology of closely related pocilloporids of the South Pacific: a case study from the Austral and Cook Islands

Platax 13: 1-25, 2016
By Anderson B. Mayfield, Chii-Shiarng Chen, Alexandra C. Dempsey, Andrew W. Bruckner
January 25, 2016

Abstract

In April-May 2013, the Khaled bin Sultan Living Oceans Foundation’s research vessel, the M.Y. Golden Shadow, traversed a ~2,000-km, predominantly unexplored region of the South Pacific Ocean, a marine transect that incorporated reefs abutting the Austral Islands of French Polynesia and the Cook Islands. In addition to conducting traditional coral reef surveys on this four-week mission, molecular biological techniques were employed to attempt to assess the health of pocilloporid corals sampled at the majority of the 59 reefs visited. Ten molecular physiological response variables were measured in a 45-sample subset of the 122 colonies sampled, and, upon utilizing multivariate statistical approaches (MSA), it was found that Pocillopora verrucosa samples from Maria Atoll in the Austral Islands differed significantly from all other sampled colonies, particularly with respect to the hsp90 mRNA expression signatures of their endosymbiotic dinoflagellate (genus Symbiodinium) communities. Additionally, a novel outlier detection technique employing heat maps and a variety of MSA identified five outliers (11% of the dataset); curiously, though, there was no effect of environment on outlier frequency. These five colonies were hypothesized to be displaying aberrant behavior with respect to their cellular physiology at the time of sampling, and it is hoped that this MSA-based outlier discovery approach could be exploited to identify corals of compromised resilience in future coral reef monitoring endeavors.