Flood plumes in the Great Barrier Reef : spatial and temporal patterns in composition and distribution

Abstract

Protecting water quality in the Great Barrier Reef World Heritage Area is recognised as one of the major challenges facing management of the area. One of the most important processes directly impacting the Great Barrier Reef (GBR) is the input of terrestrially derived nutrients and sediments to nearshore regions. This mainly occurs via river run-off, especially during periods of intense rainfall typically associated with tropical cyclones. Flood plumes occur at a time when the majority of inputs into the GBR lagoon are at peak concentrations and reefs and other inshore marine ecosystems then experience the highest concentrations of pollutants. The principal threat to the water quality of the reef arises from changes to the composition of the riverine discharge due to changed land use on coastal catchments. The characteristics of the plume water, including salinity, nutrients, sediment and toxicants pose a range of potential threats to the health of inshore ecosystems.