The relationship between sediment and water quality and riverine sediment loads in the wave-dominated estuaries of southwest Western Australia  


Authors / CoAuthors

Radke, L.C. | Prosser, I. | Robb, M. | Brooke, B. | Fredericks, D. | Douglas, G.B. | Skemstad, J.

Abstract

We examine surface sediment and water column total nutrient and chlorophyll a concentrations for 12 estuaries with average water depths <4 m, and calculated sediment loads ranging from 0.2 to 10.8 kg m-2 year-1. Sediment total nitrogen, phosphorus and organic carbon concentrations vary inversely with sediment loads due to: (i) the influx of more mineral-rich sediment into the estuaries; and (ii) increasing sediment sulfidation. Sediment total organic carbon (TOC) : total sulfur (TS) and TS : Fe(II) ratios correlated to sediment loads because enhanced sedimentation increases burial, hence the importance of sulfate reduction in organic matter degradation. Curvilinear relationships were found between a weathering index and organic matter 13C in sediment, and sediment load. The rising phase of the curve (increasing weathering, lighter isotopic values) at low to intermediate loads relates to soil erosion, whereas regolith or bedrock erosion probably explains the declining phase of the curve (decreasing weathering, heavier isotopic values) at higher sediment loads. The pattern of change for water column total nutrients (nitrogen and phosphorus) with sediment loads is similar to that of the weathering index. Most water quality problems occur in association with soil erosion, and at sediment loads that are intermediate for the estuaries studied. Limited evidence is presented that flushing can moderate the impact of sediment loads upon the estuaries.

Product Type

nonGeographicDataset

eCat Id

69512

Contact for the resource

  Custodian

EGD  

  Owner

Commonwealth of Australia (Geoscience Australia)  

  Custodian

Commonwealth of Australia (Geoscience Australia)  
Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia

Digital Object Identifier

http://dx.doi.org/10.1071/mf04044

Keywords

  • External PublicationScientific Journal Paper
( Theme )
  • water resources
( Theme )
  • erosion
( Theme )
  • coasts
( Theme )
  • geochemistry
( Theme )
  • marine
  • AU-WA
Australian and New Zealand Standard Research Classification (ANZSRC)
  • Earth Sciences
  • Published_External

Publication Date

2004-01-01T00:00:00

Creation Date

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Australian Government Security ClassificationSystem    

Classification - unclassified

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Creative Commons Attribution 4.0 International Licence    

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Use - license

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Purpose

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unknown

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geoscientificInformation

Series Information

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Unknown

Parent Information

Extents

[-35.86666, -32.0, 114.0, 122.0]

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