Queensland University of Technology, Institute for Future Environments, Gardens Point, Brisbane, Queensland, Australia.
Mar Pollut Bull. 2016 Dec 15;113(1-2):62-68. doi: 10.1016/j.marpolbul.2016.08.044. Epub 2016 Nov 8.
Increasing concerns over decreasing water quality and the state of coral reefs and seagrass meadows along the inshore and mid-shelf regions of the Great Barrier Reef has led to a large-scale government catchment sediment and nutrient reduction program. However the mechanistic understanding of how fine sediments washed out of catchments and transported within flood plumes leads to ongoing increases in turbidity at locations far downstream from estuaries long after flood plumes have dissipated is poorly understood. Essential criteria which need to be met in order for catchment-derived sediments to play a major role in nearshore water quality are proposed. Preliminary estimates of these essential criteria suggest that it is dynamically possible for fine sediments washed out of catchments during floods to be preferentially re-mobilised at downstream locations following the dissipation of flood plumes. However the longer-term influence of catchment-derived material on water quality is dependent upon the rate of degradation of floc particles that fall out of flood plumes and the rate of background deposition; neither of which are well quantified.
对大堡礁近岸和中层地区水质下降以及珊瑚礁和海草草甸状况的日益关注，促使政府开展了大规模的集水区泥沙和养分减排计划。然而，人们对于集水区泥沙被冲刷并在洪水羽流中输送，从而导致洪水羽流消散后很长一段时间内，下游河口处浊度持续增加的机理仍知之甚少。提出了为使集水区泥沙在近岸水质中发挥重要作用而需要满足的基本条件。这些基本条件的初步估计表明，在洪水期间从集水区冲刷出来的细泥沙在洪水羽流消散后，在下游位置重新迁移是完全有可能的。然而，集水区物质对水质的长期影响取决于从洪水羽流中沉降的絮体颗粒的降解速度和背景沉积速度；而这两者都没有得到很好的量化。
