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Titolo:
Phosphorus dynamics in Australian lowland rivers
Autore:
Webster, IT; Ford, PW; Hancock, G;
Indirizzi:
CSIRO Land & Water, Canberra, ACT 2601, Australia CSIRO Land & Water Canberra ACT Australia 2601 berra, ACT 2601, Australia
Titolo Testata:
MARINE AND FRESHWATER RESEARCH
fascicolo: 1, volume: 52, anno: 2001,
pagine: 127 - 137
SICI:
1323-1650(2001)52:1<127:PDIALR>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
SEDIMENT-WATER EXCHANGE; CARP CYPRINUS-CARPIO; EXPERIMENTAL MANIPULATIONS; AQUATIC SEDIMENTS; PHOSPHATE; GEOCHEMISTRY; SOLUBILITY; BILLABONGS; BIOMASS; IMPACTS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
33
Recensione:
Indirizzi per estratti:
Indirizzo: Webster, IT CSIRO Land & Water, GPO Box 1666, Canberra, ACT 2601, Australia CSIRO Land & Water GPO Box 1666 Canberra ACT Australia 2601 ia
Citazione:
I.T. Webster et al., "Phosphorus dynamics in Australian lowland rivers", MAR FRESH R, 52(1), 2001, pp. 127-137

Abstract

In freshwater systems, phosphorus is adsorbed predominantly to clay withinthe sediments. Assuming a linear adsorption/desorption isotherm, rapid equilibrium adsorption, and transport by molecular diffusion, estimates are derived for (a) the rates of exchange between the adsorbed phosphorus pool inthe sediments and the dissolved pool in the water column and (b) time scales to re-establish equilibrium after a step change in the water column phosphorus concentration. For oxic sediments, the time scale is of the order oftens of days. Anoxic release is much faster; the time scale is tens of minutes. The release of treated sewage at Narrabri abruptly raises the phosphorus concentration in the Namoi River. The concentration only returns to itsoriginal level 10-20 km downstream. A sediment adsorptive-uptake model underestimates the downstream phosphorus uptake rates. An alternative model, based on biotic uptake by Cladophora, describes reality better. It treats phosphorus transfer as controlled by physical transport processes and by the phosphorus uptake capacity of the biota. We show also that carp resuspension is faster than diffusion (6 v. 28 days) in restoring phosphorus concentrations in the water column after perturbation by rapid algal drawdown.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 23/09/20 alle ore 12:45:28