Major element chemistry of sediments from the Darling-Barwon River and itstributaries: implications for sediment and phosphorus sources

Citation
J. Olley et G. Caitcheon, Major element chemistry of sediments from the Darling-Barwon River and itstributaries: implications for sediment and phosphorus sources, HYDROL PROC, 14(7), 2000, pp. 1159-1175
Citations number
48
Categorie Soggetti
Environment/Ecology
Journal title
HYDROLOGICAL PROCESSES
ISSN journal
08856087 → ACNP
Volume
14
Issue
7
Year of publication
2000
Pages
1159 - 1175
Database
ISI
SICI code
0885-6087(200005)14:7<1159:MECOSF>2.0.ZU;2-U
Abstract
In 1991, one of Australia's longest rivers, the Darling-Barwon, experienced one of the world's largest recorded algal blooms. Nearly 1000 km of river were affected. At the time of the bloom phosphorus originating from anthrop ogenic sources was believed to be the principal cause. In this study we hav e used major element chemistry to examine the sources of sediment and sedim ent-associated phosphorus delivered to the Darling-Barwon River. We show th at the sediments are derived primarily from the sedimentary and granitic be drock areas of the catchment, not the intensively farmed basalt areas. We a lso show that the sediment currently in transport in the Darling-Barwon doe s not originate from contemporary upland erosion, but is probably derived f rom lowland areas of the catchment that contain more weathered material. Ph osphorus concentrations in the sediments are consistent with those in natur al soils of the region, and evidence from two sediment cores indicates that phosphorus concentrations have not changed significantly in the last 200 y ears. The implications of these findings for algal growth control strategie s are discussed. Copyright (C) 2000 John Wiley & Sons, Ltd.