Adapting to the effects of climate change on Australia’s deep marine reserves

Little is known about growth rates of deep-water reef forming corals or the rates atwhich these reefs accumulate. Such information is critical for determining the resilience ofthe reefs to anthropogenic impacts such as trawling and climate change. We radiocarbon datelive-caught and sub-fossil samples of the bioherm-forming coral Solenosmilia variabiliscollected from precisely known depths and locations by means of a remotely operated vehicleon seamounts south of Tasmania, Australia. The growth rate of a colony live-caught at 958 mwas estimated at 1.1mm linear extensionyr, and that of a large, recently dead specimen atleast 11 mm yr. Internal structure of the colony suggests annual deposition of growthincrements in its skeletal structure near the growing tips as the skeleton is extended andthickened. The extension rate of the live-caught specimen is similar to those reported in theliterature for S. variabilis in New Zealand and for other cold-water scleractinians, but that ofthe sub-fossil appears to be exceptionally high. Dating of additional sub-fossil materialindicates S. variabilis has been present on Tasmanian seamounts for at least the last 48,000years, and a reef accumulation rate of 0.12 mmyr.Keywords Demography, Deep-­‐sea, Scleractinia, Age, Growth rate, Holocene,Accumulation rate