Project: Exploring the adaptation and acclimatization potentials of tropical reef corals to Global Climate Change

Coral reefs around the world are in decline with much of the mortality attributed coral bleaching – the loss of their photosynthetic microalgal symbionts – resulting from global warming. Recent projections of future global climate changes (GCC) have given rise to grave concerns about the future of the world’s coral reefs, as the thermal consequences of GCC have been predicted to intensify in the next 30-50 years. To date, our ability to gauge the vulnerability of coral reefs to global warming has been limited by our lack of knowledge about the capacity for coral symbioses to acclimatize and/or adapt to thermal stress over ecological time frames. In order to be able to predict and model how corals will respond to increasing ocean temperature anomalies, we need to begin understanding the potential mechanisms of thermal tolerance in scleractinian coral symbioses. The purpose of this research is to identify the genetic response of coral species to global environmental changes by looking at the molecular mechanisms behind thermal tolerance and by identifying the genetic traits under global-change-induced selection. The specific aims were as follows:

Aim 1: Identify the candidate genes involved in modulating thermal tolerance in a model scleractinian coral, Acropora millepora.

Aim 2: Correlate the patterns of expression of candidate thermal tolerant genes in naturally-occurring corals with different thermal histories.

Aim 3: Determine the genetic variation and allele frequency changes of identified candidate thermal tolerant genes among natural populations inhabiting environment with different thermal histories, and asses the selective pressures on these genes.

This area of research is crucial to a complete understanding of the potential of tropical corals to survive and adapt to the rapid global climate changes that our planet is facing. The use of gene expression profiling approaches, under simulated and controlled experimental settings, allowed us to identify the molecular level effects that account for thermal tolerance ranges, and type of  changes in gene expression is needed to achieve thermal acclimatization. Moreover, this project proposed to use the identified candidate genes involved in the acclimatization process of thermal tolerance as genetic markers to monitor whether seawater temperature changes influence coral species at the level of DNA sequences.