Year 3 (2008/2009) Project Leader:  Mr Jon Brodie, James Cook University

Research Organisation: AIMS, JCU, ANU

The principal objectives of this project are to assess the risk to GBR ecosystems from the various land-sourced pollutants entering the GBR. Risk will be assessed by establishing explicit links between the sources of pollutants within catchments (land uses, land management practices), delivery of these materials to the river mouths (including trapping and transformation processes) and transport of the materials in the GBR lagoon (including trapping, transformation and storage regimes). Thus exposure of GBR ecosystems (particularly coral reefs, seagrass meadows, mangrove forests and the water column ecosystem) to land-sourced pollutants can be determined and, in combination with the known toxicities/effect concentrations of the pollutants, risk can be assessed.

The project will characterise and obtain a distinct “fingerprint” of the fine sediments (mud fraction) entering the marine environment, using their isotopic and elemental properties, and link these to the sediment sources of the major terrestrial catchments. It will also examine historical changes in the delivery of terrestrial materials from the major river systems in the Rockhampton-Cairns region to the marine environment using coral and sediment cores. This will involve determining transport mechanism, residences time and fate of terrigenous materials in the floodplains, estuaries, inshore reefal areas and mid-shelf regions of the Great Barrier Reef, and develop and apply new technologies to specifically trace pathways of the key nutrient elements phosphorus and nitrogen from the terrestrial catchments, through estuaries, inshore coastal zones to the mid-shelf of the Great Barrier Reef.

In Year 3 (2008/2009) Project 3.7.2 aims to:

1. Trace materials in the terrestrial environment – generation, transport, transformation, trapping;

2. Trace materials in the marine environment – transport, transformation, trapping and fate; and
   

3. Trace inshore-offshore sediment transport in the Wet Tropics – relationships between sediment input and transport and regional turbidity regimes.

Lewis, S. E., Brodie, J. E., Bainbridge, Z. T., Rhode, K. W., Davis, A. M., Masters, B. L., Maughan, M., Devlin, M. J., Mueller, J. F. and Shaffelke, B. (2009) Herbicides:  A new threat to the Great Barrier Reef.  Environmental Pollution (In Press) [Access this article via www.elsevier.com/locate/envpol]

Hughes, A. O., Olley, J. M., Croke, J. C. and McKergow, L. A. (2009) Sediment source changes over the last 250 years in a dry-tropical catchment, central Queensland, Australia.  Geomorphology (In Press) [Access this article via www.elsevier.com/locate/geomorph]