Dimethylsulphide (DMS) production in corals, sediments and benthic microalgae
Dimethylsulphide (DMS) is a trace sulphur substance that is produced by either enzymatic cleavage of its main precursor dimethylsulphoniopropionate (DMSP) or reduction of dimethylsufoxide (DMSO) in various taxa in higher plants, algae and marine phytoplankton. DMS is believed to play an important role in climate regulation by enhancing the formation of cloud condensation nuclei (CCN) which then form stratocumulous clouds, reducing solar radiation levels over the ocean. Previous studies have shown that staghorn coral (e.g Acropora sp.), a dominant coral in the Indo-Pacific region, produce significant amounts of dissolved DMS and DMSP, suggesting that reefs could participate in a regional climate feedback, which lowers temperatures. Chamber experiments with Acropora intermedia collected from Heron Island coral cay in the central Great Barrier Reef have shown this coral species releases high concentrations of atmospheric DMS. However, when this coral was stressed with higher light and temperature levels, atmospheric DMS emissions decreased significantly and almost completely shut down when temperatures were increased by only 2oC above ambient seawater temperatures. These results suggest that exposure to elevated temperatures beyond the coral's tolerance threshold could have negative feedback effects on DMS emission, cloud condensation nuclei and regional climate where coral biomass is high. Our project will aim to understand better the mechanisms involved in the DMS and DMSP production as well as atmospheric DMS emission by Staghorn corals during high temperature exposure. We are also aiming to extend this project to sediments and benthic microalgae in order to have a broader understanding of the marine sulphur cycle.
Swan H. B., R. W. Crough, P. Vaattovaara, G. B Jones, E. S. M. Deschaseaux, B. D. Eyre, B. Miljevic and Z. D. Ristovski. 2016. Dimethylsulfide and other biogenic volatile organic compounds emitted from branching coral and reef seawater: Potential sources of secondary aerosol over the Great Barrier Reef. Journal of Atmospheric Chemistry 73, 303-328.
Swan, H. B., Ivey, J. P. Jones, G. B. and Eyre, B. D. 2015. The validation and measurement uncertainty of an automated gas chromatograph for marine studies of atmospheric dimethylsulfide. Analytical Methods 7, 3893-3902.
Deschaseaux, E.S.M., Kiene, R. P., Oswald, L., Jones, G. B., Deseo, M. A., Swan, H. B. and Eyre, B. D. 2014. Dimethylsulphoxide (DMSO) in biological samples: a comparison of two methods based on TiCl3 or NaBH4 reduction. Marine Chemistry 164, 9-15.
Deschaseaux, E.S.M., Beltran, V. H., Jones, G. B., Deseo, M. A., Swan, H.B., Harrison, P. L. and Eyre, B. D. 2014. Comparative response of DMS and DMSP concentrations in Symbiodinium clades C1 and D1 under thermal stress. Journal of Experimental Marine Biology and Ecology 459, 181-189.
Deschaseaux, E, G. Jones, M.A. Deseo, K.M. Shepherd, R.P. Kiene, H.B. Swan, P.L. Harrison, and B.D. Eyre. 2014. Effects of environmental variables on dimethylated sulphur compounds and their role in the antioxidant system of the coral symbiosis. Limnology and Oceanography 59, 758-768.