Bass, A.M., Bird, M.I., Liddell, M.J., and Nelson, P. (2011) Fluvial dynamics of dissolved and particulate organic carbon during periodic one-flood events in a steep tropical rainforest catchment. In: Abstracts from 11th Australasian Environmental Isotopes Conference and 4th Australasian Hydrogeology Research Conference. p. 21. From: 11th Australasian Environmental Isotopes Conference and 4th Australasian Hydrogeology Research Conference, 12-14 July 2011, Cairns, QLD, Australia.

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Abstract

In small catchments with rapid flood pulses, detailed temporal data is essential as high discharge events can be measured in hours and days, rather than weeks and months. Using high resolution (15 minutes) sampling procedures, we studied the dynamics of aquatic dissolved and particulate organic carbon (DOC and POC) export through episodic discharge events in a small pristine rainforest catchment in north-east Australia between November 2009 and March 2010. The concentration of DOC and POC peaked during times of high stream discharge, reflecting an increased mobilisation of soil water carbon stocks. DOC was the major form of organic carbon in the stream, over 70% of the total carbon export. 84% of the total organic carbon exported from the catchment occurred during significant discharge events (discharge >50 L s-l) measured during 9% of the study. Export of DOC and POC totalled 195 and 68 kg km-2 month-1, respectively. with a DOC:POC ratio of 2.9 ± 0.9. If this sub-catchment was sampled at weekly intervals the lateral export of carbon would have been underestimated by between 49% and 78% for DOC and POC, respectively. Preliminary 613C and molar C:N values of the dissolved and particulate matter which suggested that during discharge events less microbially processed material from the upper soil layers dominated organic matter export, with the opposite being true in non-flood conditions. Not only will the quantities of organic matter exported change in different discharge conditions, but the source and quality may also shift.

Item ID:	19758
Item Type:	Conference Item (Abstract / Summary)
Date Deposited:	14 Feb 2012 04:55
FoR Codes:	04 EARTH SCIENCES > 0402 Geochemistry > 040204 Organic Geochemistry @ 100%
SEO Codes:	96 ENVIRONMENT > 9611 Physical and Chemical Conditions of Water > 961103 Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and @ 100%
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• Fluvial dynamics of dissolved and particulate organic carbon during periodic one-flood events in a steep tropical rainforest catchment. (deposited 14 Feb 2012 04:55) [Currently Displayed]
  • Fluvial dynamics of dissolved and particulate organic carbon during periodic discharge events in a steep tropical rainforest catchment. (deposited 14 Feb 2012 05:05)