Measuring sediment grain size across the catchment to reef continuum: improved methods and environmental insights
Journal Publication ResearchOnline@JCUAbstract
Sediments collected within freshwater, estuarine and marine habitats were used to trial various chemical and physical pre-treatments to develop a systematic protocol for grain-size analysis using laser diffraction. Application of this protocol mitigates the influence of bio-physical processes that may transform grain-size distributions, enabling the characterisation and quantification of 'primary' mineral sediments across the complex freshwater-marine continuum to be more reliably assessed. Application of the protocol to two Great Barrier Reef (Australia) river catchments and their estuaries reveals the ecologically relevant <20 μm fraction comprises a larger component of exported sediment than existing methods indicate. These findings are highly relevant when comparing measured data to grain-size-specific modelled sediment loads and water-quality targets. Finally, adoption of the protocol also improves the environmental interpretation of the influence of 'terrigenous sediment' in marine settings, including quantification of newly-delivered flood plume sediment.
Journal
Marine Pollution Bulletin
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Volume
168
ISBN/ISSN
1879-3363
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Pages Count
21
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Publisher
Elsevier
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Publisher Location
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Publish Date
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Date
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EISSN
N/A
DOI
10.1016/j.marpolbul.2021.112339