Terry Hughes: Dredging on the Great Barrier Reef

Coal mining and natural gas extraction (fracking) in Queensland, Australia are expanding rapidly. Apart from the enormous additional CO2 emissions, the expansion of huge ports and dumping of dredge spoil within the Great Barrier Reef (GBR) World Heritage Area have prompted UNESCO to consider including the GBR on their list of “World Heritage Areas in Danger”. The Australian Federal government and the State of Queensland earn billions of dollars in royalties from mining and they are now fast-tracking new mega-coal mines and the largest coal and gas ports in the world. These officials claim that dredging and dumping >100 million cubic meters of sediment will cause no significant damage to the environment.

However, two new scientific studies from James Cook University prove that dredging is a major threat to marine ecosystems, including coral reefs. A recent study by Pollock et al. shows that dredging-associated sedimentation and turbidity dramatically increase coral disease levels on nearby reefs. Essentially, corals get sick more often when they are stressed by reduced light levels and sedimentation (http://dx.plos.org/10.1371/journal.pone.0102498). A separate study by Burns examines the dispersal of fine particles, and shows that hydrocarbons from coal have already dispersed across the width of the GBR, and are approaching international benchmarks for toxicity in suspended sediments and on the benthos (http://dx.doi.org/10.1016/j.ecss.2014.04.001).
Together these benchmark studies prove that dredging is a major threat to the Great Barrier Reef. I encourage you to read them.
Yesterday, Australia became the first country to repeal legislation that curbs CO2 emissions.

Paper citations:
Pollock FJ, Lamb JB, Field SN, Heron SF, Schaffelke B, Shedrawi G, Bourne DG, Willis BL (2014) Sediment and turbidity associated with offshore dredging increase coral disease prevalence on nearby reefs. PLoS ONE 9(7): e102498. doi:10.1371/journal.pone.0102498
Burns KA (2014) PAHs in the Great Barrier Reef Lagoon reach potentially toxic levels from coal port activities. Estuarine, Coastal and Shelf Science 144:39-45. http://dx.doi.org/10.1016/j.ecss.2014.04.001

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Prof. Terry Hughes FAA
Director, ARC Centre of Excellence for Coral Reef Studies
James Cook University
Townsville, QLD 4811, AUSTRALIA
Fax: 61 (0) 4781-6722
tel: 61 (0)7-4781-4000
http://www.coralcoe.org.au/

Special thanks to Coral-list

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