Environmental and calcification data for widespread scope for coral adaptation under combined ocean warming and acidification

Reef-building coral populations are at serious risk of collapse due to the
combined effects of ocean warming and acidification. However, many corals
show potential to adapt to changing ocean conditions. Here, we examine the
broad sense heritability (H2) of coral calcification rates across an
ecologically and phylogenetically diverse sampling of eight of the primary
reef-building corals across the Indo-Pacific. We show that all eight
species exhibit relatively high heritability of calcification rates under
combined warming and acidification (0.23-0.56). Further, tolerance to each
factor is positively correlated, and the two factors do not interact in
most species, contrary to the idea of tradeoffs between temperature and pH
sensitivity. All eight species can co-evolve tolerance to elevated
temperature and reduced pH. Using these values together with historical
data, we estimate potential increases in thermal tolerance of 1.0-1.7 °C
over the next 50 years, depending on species. None of these species are
likely capable of keeping up with a high global change scenario, and
climate change mitigation is essential if reefs are to persist. Such
estimates are critical for our understanding of how corals may respond to
global change, accurately parameterizing modeled responses, and predicting
rapid evolution.