The Reef Sulphur Cycle: Influence on Climate and Ecosystem Services

Abstract

Research in the western Pacific over the last 15 years has shown that hard corals contain exceptionally high concentrations of a sulphur substance called dimethylsulphoniopropionate or DMSP which can produce a volatile sulphur substance called dimethylsulphide or DMS. Of all the different coral species, staghorn coral or Acropora species produce the greatest amounts of atmospheric DMS. Oxidation of atmospheric DMS produces a sulphate aerosol which can potentially form cloud condensation nuclei (CCN) leading to low level cloud development. An increasing amount of evidence now suggests that DMS emitted from coral reefs could keep sea surface temperatures (SSTs) cooler (~1 °C between 10–20 °S) in the Great Barrier Reef, and western Pacific, through this reef produced low level cloud climate feedback. The production of these natural sulphur substances from coral reefs and their effect on regional climate, bird, bacterial and fish behaviour, and possible use as Polynesian navigational aids are reviewed, providing evidence of a very valuable and important ecosystem service not previously described.