title: Keep up or drown: adjustment of western Pacific coral reefs to sea-level rise in the 21st century.
abstract: Since the Mid-Holocene, some 5000 years ago, coral reefs in the Pacific Ocean have been vertically constrained by sea level. Contemporary sea-level rise is releasing these constraints, providing accommodation space for vertical reef expansion. Here, we show that Porites microatolls, from reef-flat environments in Palau (western Pacific Ocean), are 'keeping up' with contemporary sea-level rise. Measurements of 570 reef-flat Porites microatolls at 10 locations around Palau revealed recent vertical skeletal extension (78±13 mm) over the last 6-8 years, which is consistent with the timing of the recent increase in sea level. We modelled whether microatoll growth rates will potentially 'keep up' with predicted sea-level rise in the near future, based upon average growth, and assuming a decline in growth for every 1°C increase in temperature. We then compared these estimated extension rates with rates of sea-level rise under four Representative Concentration Pathways (RCPs). Our model suggests that under low-mid RCP scenarios, reef-coral growth will keep up with sea-level rise, but if greenhouse gas concentrations exceed 670 ppm atmospheric CO2 levels and with +2.2°C sea-surface temperature by 2100 (RCP 6.0 W m(-2)), our predictions indicate that Porites microatolls will be unable to keep up with projected rates of sea-level rise in the twenty-first century.
authors.affiliation: Department of Biological Sciences , Florida Institute of Technology , Melbourne, FL, USA.
authors.forename: R
authors.initials: R
authors.lastname: van Woesik
authors.affiliation: Palau International Coral Reef Center , PO Box 7086, Koror, PW 96940, Republic of Palau.
authors.forename: Y
authors.initials: Y
authors.lastname: Golbuu
authors.affiliation: School of Biology , University of Queensland , St Lucia, Queensland, Australia.
authors.forename: G
authors.initials: G
authors.lastname: Roff
keywords: Pacific; climate change; coral reefs; corals; sea-level rise