Wild populations increasingly experience extreme conditions as climate change amplifies environmental variability. How individuals respond to environmental extremes determines the impact of climate change overall. The variability of response from individual to individual can represent the opportunity for natural selection to occur as a result of extreme conditions. Here, we experimentally replicated the natural exposure to extreme temperatures of the reef lagoon at Ofu Island (American Samoa), where corals can experience severe heat stress during midday low tide. We investigated the bleaching and transcriptome response of 20 Acropora hyacinthus colonies 5 and 20 h after exposure to control (29 °C) or heated (35 °C) conditions. We found a highly dynamic transcriptome response: 27% of the coral transcriptome was significantly regulated 1 h postheat exposure. Yet 15 h later, when heat-induced coral bleaching became apparent, only 12% of the transcriptome was differentially regulated. A large proportion of responsive genes at the first time point returned to control levels, others remained differentially expressed over time, while an entirely different subset of genes was successively regulated at the second time point. However, a noteworthy variability in gene expression was observed among individual coral colonies. Among the genes of which expression lingered over time, fast return to normal levels was associated with low bleaching. Colonies that maintained higher expression levels of these genes bleached severely. Return to normal levels of gene expression after stress has been termed transcriptome resilience, and in the case of some specific genes may signal the physiological health and response ability of individuals to environmental stress.

Raw_counts_dataRead counts for all 152 samples and 33,496 contigs.Supp_mat_Spreadsheet1_Raw_counts_data.xlsxFull experimental designExperimental design for DESeq analysis.fullRTEdesign.csvDESeq Analysis 5hR commands for DESeq analysis on 5 hr data.DESeqAnalysis5h_nov2013.RDESeq Analysis 20hR commands for DESeq analysis on 20 hr data.DESeqAnalysis20h_nov2013.R33,496 Acropora hyacinthus contigsFasta file of the 33,496 assembled contiguous sequences from Acropora hyacinthus type E from Ofu Island, American Samoa.33496_Ahyacinthus_CoralContigs.fasta33496 Acropora hyacinthus Contigs AnnotationAnnotations for the 33,496 contigs from Acropora hyacinthus.33496_Ahyacinthus_Contigs_Annotation.xlsxRead counts for 5 hr samplesInput file for DESeq analysis on 5 hr samples.CombinedCounts_5h.txtRead counts for 20 hr samplesInput file for DESeq analysis on 20 hr samples.CombinedCounts_20h.txt