Authors / CoAuthors
Palmer, D.W. | Fredericks, D.J. | Smith, C.S. | Tindall, C. | Heggie, D.T.
Abstract
Executive Summary Between the 6th and 10th December 1999, the Australian Geological Survey Organisation, in collaboration with the NSW Environment Protection Authority and the Department of Land and Water Conservation, conducted a field survey of Durras Lake, South East, NSW. The objectives of the survey were to: (i) measure the net fluxes of sediment metabolites from the major sediment facies; (ii) estimate the rate and significance of denitrification; and (iii) field test modifications to AGSO automated benthic chambers. Eight chambers were deployed on two sediment facies (sand and mud). Time series of water samples collected from these chambers were used to determine nutrient flux rates and sediment respiration. The following observations were made: At the time of the survey, the deep mud basin was stratified with an anoxic, saline bottom layer and fresher well oxygenated surface waters.. Respiration dominated (ie oxygen demand of the sediments was greater than production via photosynthesis) in each chamber incubation in the mud and sand facies. TCO2 fluxes ranged between 13.3 ?57.4 mmol m-2 day-1 in the mud facies and 39.0 ?106.3 mmol m-2 day-1 in the sand facies. Organic carbon being degraded in the deeper mud basin was primarily of a diatomaceous composition. Dark respiration in the sand facies was not consistent with a mainly diatomaceous origin of organic carbon. Denitrification efficiencies were relatively low in both the sand and mud facies. Low denitrification rates in the mud facies may be related to the low concentrations of dissolved oxygen in the water overlying the sediments. Tests of AGSO system for direct measurement of denitrification using benthic chambers and N2 measurement by quadropole mass spectrometer were successful.
Product Type
nonGeographicDataset
eCat Id
40715
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Custodian
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External PublicationReport
- ( Theme )
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- geochemistry
- ( Theme )
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- marine
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- AU-NSW
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2000-01-01T00:00:00
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geoscientificInformation
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[-35.67, -35.58, 150.25, 150.32]
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