Hobart

Seminar abstract

Tuesday 5 December 2006, 11.30 am (Tas time)
CSIRO Auditorium, Hobart

Graham Jones
School of Environmental Science and Management
Southern Cross University

The DMS sulphur cycle and climate change over the Great Barrier Reef

This talk outlines research carried out in the Great Barrier Reef (GBR) on dimethylsulphide (DMS), a trace sulphur gas, which affects the radiative climate of the atmosphere.

Seasonal studies at several reefs in the GBR have shown that coral reefs produce abundant amounts of DMS, and its precursor compound, dimethylsulphoniopropionate (DMSP), present in coral zooxanthellae. The size of the reef, state of the tide, and nutrient status of the reef all seem to affect DMS and DMSP production in the water column. For inshore reefs dissolved DMS is strongly correlated with sea surface temperature, and increases in atmospheric DMS often occur in the daylight hours over reefs.

Chamber experiments with Acropora corals demonstrate that the production of DMS and DMSP from coral zooxanthellae is significant, increasing when temperatures and sunlight increase. However, when temperature stress is prolonged DMS production seems to shut down. A bleaching experiment on corals with different “clades” of zooxanthellae suggests that zooxanthellar DMSP increases when corals are subjected to increases in seawater temperature (30-32 o C), with clade C zooxanthellae displaying the greatest increase in cellular DMSP when stressed.

These results suggest that DMS and DMSP may act as an antioxidant in coral zooxanthellae. In 1998 and 2002 over 650 reefs in the GBR bleached white when SST's reached 31 o C. Whilst greenhouse gas warming may have been responsible, could S-aerosols produced from the reefs themselves also have an effect, or is DMS production from these coral reefs decreasing at these high temperatures?

Bibliography:
Graham Jones is an Associate Professor in Earth System Science from the School of Environmental Science and Management at Southern Cross University in northern New South Wales . Graham lectures in Environmental Chemistry, Coastal Geomorphology, and Global Climate & Ocean Systems; and for the last 16 years has carried out research on the DMS-S cycle in the Great Barrier Reef and Southern Ocean. He is a member of the Australian Academy of Sciences National Committee for Antarctic Research (NCAR), and a member of Australia 's International Polar Year (IPY) committee.

[back]

Location:
CSIRO = Marine Laboratories Auditorium, Castray Esplanade, Hobart

For further information, or to schedule a seminar, contact:
To schedule a seminar, contact:
Karen Wild-Allen, (Oceanographic seminars) CSIRO Marine and Atmospheric Research (03) 6232 5010
Piers Dunstan, (Biological seminars) CSIRO Marine and Atmospheric Research (03) 6232 5382
Annabel Ozimec (seminar administrator) CSIRO Marine and Atmospheric Research (03) 6232 5462
Sandra Zicus, Antarctic Climate and Ecosystems CRC (03) 6226 7888 & Institute of Antarctic and Southern Ocean Studies (IASOS) University of Tasmania (03) 6226 2509

Last updated 12/10/06