Data from: Low recruitment due to altered settlement substrata as primary constraint for coral communities under ocean acidification

The future of coral reefs under increasing CO2 depends on their capacity
to recover from disturbances. To predict the recovery potential of coral
communities that are fully acclimatized to elevated CO2, we compared the
relative success of coral recruitment and later life stages at two
volcanic CO2 seeps and adjacent control sites in Papua New Guinea. Our
field experiments showed that the effects of ocean acidification (OA) on
coral recruitment rates were up to an order of magnitude greater than the
effects on the survival and growth of established corals. Settlement
rates, recruit and juvenile densities were best predicted by the presence
of crustose coralline algae, as opposed to the direct effects of seawater
CO2. Offspring from high CO2 acclimatized parents had similarly impaired
settlement rates as offspring from control parents. For most coral taxa,
field data showed no evidence of cumulative and compounding detrimental
effects of high CO2 on successive life stages, and three taxa showed
improved adult performance at high CO2 that compensated for their low
recruitment rates. Our data suggest that severely declining capacity for
reefs to recover, due to altered settlement substrata and reduced coral
recruitment, is likely to become a dominant mechanism of how OA will alter
coral reefs.