Fine sediment dynamics on the inner shelf of the Great Barrier Reef during a flood

This study monitered the fine sediment dynamics during a moderate wet season event in 2007. The study area was located offshore and north of the mouths of the Tulla and Murray rivers in, around the Dunk and Bedarra Islands in the Northern Great Barrier Reef region. Moorings were deployed between 20 January and 19 February 2007 on the inner shelf. Upward looking, bottom-mounted RDI Acoustic Doppler Current Profilers (ADCP) and, at the inshore sites, Nortek single point current meters were deployed at sites along two cross-shore transects.Analite nephelometers, some with LiCor light meters, and sediment traps were also deployed at the upper and lower reef slopes at the eastern and western sides of the islands 0.5 m above the substratum, and at four of the mooring sites. SBE37 SeaBird salinometers, Analite nephelometers, and Nortek Awac wave gauges were deployed at 4 m depth, and recorded data in bursts of 2048 samples at 0.5 s intervals. All other instruments recorded data at 10 min intervals.Vertical profiles of temperature, salinity, dissolved oxygen concentration (DO), and suspended sediment concentration (SSC) were also obtained using a SeaBird SBE19plus CTD cum-OBS profiler at all mooring sites and along a cross-shelf transect on February 2, 4, 18 and 19, 2007.Surface water samples were taken and processed for concentrations of dissolved and particulate nutrients, total suspended solids, chlorophyll and phaeopigments.Sedimentation rates were calculated from 20 sediment traps. Dried material from sediment traps was analysed for percentages of carbonate, organics (loss after ignition), calcium, aluminum, iron and nutrients (total phosphorus and nitrogen, total organic and inorganic carbon.The aim of this study was to report the fate of mud and nutrients during a river flood to the Great Barrier Reef.