Coral reef growth in an era of rapidly rising sea level: predictions and suggestions for long-term research

Abstract

Coral reef growth is intimately linked to sea level. It has been postulated that over the next century, sea level will rise at a probable average rate of 15 mm/year, in response to fossil fuel emissions, heating, and melting of the Antarctic ice cap. This predicted rate of sea level rise is five times the present modal rate of vertical accretion on coral reef flats and 50% greater than the maximum vertical accretion rates apparently attained by coral reefs. We use these predictions and observations to offer the following hypothesis for reef growth over the next century. The vertical accretion rates of protected reef flats will accelerate from the present modal rate up to the maximum rate, in response to the more rapidly rising sea level. This more rapid vertical accretion rate will be insufficient to keep up with sea level rise, if present predictions prove to be correct. Less protected reef flats will slow their rate of growth as they become inundated and subjected to erosion by progressively larger waves. This projected sea level rise and postulated reef response will provide an opportunity for long-term studies of the response of coral reef systems to a predictable and measurable forcing function. If the scientific benefits from this uncontrolled global experiment are to be maximized, it will be necessary to establish a permanent international coordinating body to assist with the identification and preservation of long-term study sites and to provide guidelines for baseline data surverys, methods selection and comparison, and other procedures and decisions.