Variability in fluvial suspended and streambed sediment phosphorus fractions among small agricultural streams.

Autor: Sandström S; Dep. of Aquatic Sciences and Assessment, Swedish Univ. of Agricultural Sciences, P.O. Box 7050, Uppsala, Sweden., Futter MN; Dep. of Aquatic Sciences and Assessment, Swedish Univ. of Agricultural Sciences, P.O. Box 7050, Uppsala, Sweden., O'Connell DW; Dep. of Civil and Environmental Engineering, Museum Building, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland., Lannergård EE; Dep. of Aquatic Sciences and Assessment, Swedish Univ. of Agricultural Sciences, P.O. Box 7050, Uppsala, Sweden., Rakovic J; Dep. of Soil and Environment, Swedish Univ. of Agricultural Sciences, P.O. Box 7014, Uppsala, Sweden., Kyllmar K; Dep. of Soil and Environment, Swedish Univ. of Agricultural Sciences, P.O. Box 7014, Uppsala, Sweden., Gill LW; Dep. of Civil and Environmental Engineering, Museum Building, Trinity College Dublin, the University of Dublin, Dublin 2, Ireland., Djodjic F; Dep. of Aquatic Sciences and Assessment, Swedish Univ. of Agricultural Sciences, P.O. Box 7050, Uppsala, Sweden.
Jazyk: angličtina
Zdroj: Journal of environmental quality [J Environ Qual] 2021 May; Vol. 50 (3), pp. 612-626. Date of Electronic Publication: 2021 Apr 05.
DOI: 10.1002/jeq2.20210
Abstrakt: Agriculture is a major source of sediment and particulate phosphorus (P) inputs to freshwaters. Distinguishing between P fractions in sediment can aid in understanding its eutrophication risk. Although streams and rivers are important parts of the P cycle in agricultural catchments, streambed sediment and especially fluvial suspended sediment (FSS) and its P fractions are less studied. To address this knowledge gap, seasonal variations in FSS P fractions and their relation to water quality and streambed sediment were examined in three Swedish agricultural headwater catchments over 2 yr. Sequential fractionation was used to characterize P fractions in both streambed sediment and FSS. All catchments had similar annual P losses (0.4-0.8 kg ha -1 ), suspended solids (124-183 mg L -1 ), and FSS total P concentrations (1.15-1.19 mg g -1 ). However, distribution of P fractions and the dominant P fractions in FSS differed among catchments (p < .05), which was most likely dependent on differences in catchment geology, clay content, external P sources, and flow conditions. The most prominent seasonal pattern in all catchments was found for iron-bound P, with high concentrations during low summer flows and low concentrations during winter high flows. Streambed sediment P fractions were in the same concentration ranges as in FSS, and the distribution of the fractions differed between catchments. This study highlights the need to quantify P fractions, not just total P in FSS, to obtain a more complete understanding of the eutrophication risk posed by agricultural sediment losses.
(© 2021 The Authors. Journal of Environmental Quality © 2021 American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.)
Databáze: MEDLINE
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