Cryptic lineages respond differently to coral bleaching

Coral cover is decreasing worldwide largely as a result of a rise in seawater temperatures that triggers coral bleaching and induces coral mortality. How coral reefs will respond to climate change will be a function of genetic variation and how it is partitioned within and among species. A critical initial step is to accurately delineate species and quantify their physiological potential to cope with heat stress. Cryptic species are morphologically similar but genetically distinct and may respond physiologically different to climate change. A dominant Caribbean reef builder severely affected by climate change is the mountainous star coral, Orbicella faveolata. Recently, Dziedzic et al. (2019) reported quantitative genetic variation in the physiological response to thermal stress in a single population of this species, suggesting that variation within populations will allow these corals to adapt to rising ocean temperatures. We reanalyzed their data and found multiple cryptic lineages ra...