δ13C provides a robust indicator of the sources of suspended sediment in a tropical river traversing forested and agricultural land

Hateley, Louise, Nelson, P.N., and Amiotte-Suchet, P. (2011) δ13C provides a robust indicator of the sources of suspended sediment in a tropical river traversing forested and agricultural land. In: Abstracts from 11th Australasian Environmental Isotopes Conference and 4th Australasian Hydrogeology Research Conference, p. 36. From: 11th Australasian Environmental Isotopes Conference and 4th Australasian Hydrogeology Research Conference, 12-14 July 2011, Cairns, QLD, Australia.

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Abstract

Degradation of freshwater and marine ecosystems by sediment and associated pollutants is widespread, We set out to determine the sources of suspended sediment, using composite fingerprinting, in the Tully River, which discharges into the Great Barrier Reef lagoon. Samples of suspended sediment combined over a whole wet season were taken from the Tully River and two of its main tributaries, Samples of potential source material were taken from 102 sites covering several land use and geological categories. When all 23 measured properties (mostly total elemental contents) were included in the fingerprint, 50% of the suspended sediment in the Tully River was attributed to sugarcane surface soil, 15% to other land uses, and 35% to channels, which are all in sugarcane growing areas on Quaternary alluvium and colluvium. However, mean relative errors were quite high. When mineral properties were excluded from the fingerprint, land use sources could be discriminated with reduced mean relative errors, δ13C separated forest versus sugarcane, and 613C in combination with C:N ratio separated surface soil versus channels. Fingerprints based on organic properties attributed >60% of suspended sediment to channel erosion. The results show that caution is needed when applying and interpreting the composite fingerprinting approach in some environments.

Item ID: 19761
Item Type: Conference Item (Abstract / Summary)
Date Deposited: 14 Feb 2012 05:17
FoR Codes: 04 EARTH SCIENCES > 0406 Physical Geography and Environmental Geoscience > 040607 Surface Processes @ 50%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050206 Environmental Monitoring @ 50%
SEO Codes: 96 ENVIRONMENT > 9614 Soils > 961402 Farmland, Arable Cropland and Permanent Cropland Soils @ 50%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 50%
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