HR: 0800h
AN: B31D-0612    [Abstracts]
TI: Trace element ratios in bivalve shells as records of environmental conditions
AU: * Tynan, S
EM: sarah.tynan@anu.edu.au
AF: CRC LEME, DEMS, The Australian National University, Bldg 47, ANU Daley Rd, Canberra, ACT 0200, Australia
AU: Opdyke, B
EM: bradley.opdyke@anu.edu.au
AF: CRC LEME, DEMS, The Australian National University, Bldg 47, ANU Daley Rd, Canberra, ACT 0200, Australia
AU: Welch, S
EM: susan.welch@anu.edu.au
AF: CRC LEME, DEMS, The Australian National University, Bldg 47, ANU Daley Rd, Canberra, ACT 0200, Australia
AU: Beavis, S
EM: sara.beavis@anu.edu.au
AF: CRC LEME, FSES, The Australian National University, Bldg 42, ANU, Canberra, ACT 0200, Australia
AB: Stable isotope and trace element data from the carbonate of both marine and freshwater bivalves are proving to be useful tools in studies of palaeoclimate and environmental change. However, much of the work already done has shown that the trace element ratios in bivalve shells exhibit a complex relationship with the ambient environment and caution must be exercised when attempting to use them as environmental proxies. This work examines the feasibility of using the trace element ratios Mg/Ca, Sr/Ca, Ba/Ca and Mn/Ca of the shells of a number of different species of bivalves as records of the temperature and salinity of their ambient aquatic environment. The species analysed were the estuarine oysters Saccostrea glomerata, Ostrea angasi, and Crassostrea gigas, an estuarine mussel, Mytilus galloprovincialis, and the freshwater mussel Velesunio ambiguus. The estuarine shells were taken from monitoring experiments conducted over a period of 12 months at two different field sites. Freshwater shells were collected wild, from locations close to water monitoring stations. Preliminary results show distinct variations in the Mg/Ca of O. angasi shells with an apparent seasonal pattern. V. ambiguus shells show clear patterns in Mn/Ca, linked to environmental variations.
DE: 0424 Biosignatures and proxies
DE: 0489 Trace element cycling (4875)
DE: 0497 Wetlands (1890)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting