Authors / CoAuthors
Heggie, D.T. | Skyring, G.W.
Abstract
The ratio of benthic silicate (SiO4 or DSi1) vs carbon dioxide (CO2) fluxes at 299/341 (87%) sites in 10 Australian estuaries was 0.15 to 0.19 (r2=0.8), indicating diatoms 2,3 as the major type of organic material (OM) being degraded in the sediments . Diatoms contributed 33% of the degradable OM at the remaining 42 (13%) sites. Diatomaceous phytoplankton was thus central to nutrient cycling in these estuaries. Dam-induced DSi depletion in coastal waters, a cause of toxic non-silicious algal blooms is now a global problem1. Our investigation indicated that DSi has another and potentially important global role in nutrient cycling in coastal waterways, also prompting a new DSi-dependent nutrient cycling model. The Si-opal inclusion (frustule) in living diatoms confers a density that causes rapid settling to the sediments4 where denitrification recycles N2 to an atmospheric sink, in this way lowering internal N cycling and preventing eutrophication5. Also, DSi is recycled quantitatively to the water column, participating in repeated cycles of diatom productivity. The silicate-diatom-sediment nexus is thus sustained and the N-loss processes of denitrification and burial are sustained.
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nonGeographicDataset
eCat Id
61647
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
Keywords
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- External PublicationArticle
- ( Theme )
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- coasts
- ( Theme )
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- marine
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2004-10-05T00:00:00
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geoscientificInformation
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