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Research article - Peer-reviewed, 2020

New Insights Into Legacy Phosphorus From Fractionation of Streambed Sediment

Lannergard, Emma E.; Agstam-Norlin, Oskar; Huser, Brian J.; Sandstrom, Sara; Rakovic, Jelena; Futter, Martyn N.

Abstract

Streambed and lake sediment was studied in Savjaan, a eutrophic mesoscale catchment (722 km(2)) in central Sweden. Triplicate sediment cores from five lakes and nine streams, ranging from headwater to fourth order, were sampled. The sediment was analyzed with a sequential extraction method, where six different phosphorus (P) fractions were measured. The results showed that streambed sediments store considerable amounts of P and in some cases have comparable P contents (g/kg DW) to lake sediment. Land use, soil type, and drainage area (location in the catchment) had a significant effect on the different P fractions found in surficial sediments. Sediment from lakes and forested headwater streams generally had high proportions of organic P and iron bound P. In larger streams located in agricultural areas on clay soils closer to the catchment outlet, with dense sediment and a relatively low proportion of organic matter, P was to a larger extent bound to calcium. Streambed sediment may be an important catchment scale P store and should be considered when modeling catchment P dynamics. The large stores of streambed legacy P should also be considered when performing ditch maintenance to avoid unnecessary mobilization of bioavailable P.

Keywords

catchment study; streambed sediment; phosphorus fractionation; internal loading; legacy phosphorus; ditch maintenance

Published in

Journal of Geophysical Research: Biogeosciences
2020, volume: 125, number: 9, article number: e2020JG005763
Publisher: AMER GEOPHYSICAL UNION

Authors' information

Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Agstam-Norlin, Oskar (Agstam, Oskar)
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment
Swedish University of Agricultural Sciences, Department of Aquatic Sciences and Assessment

Sustainable Development Goals

SDG6 Clean water

UKÄ Subject classification

Oceanography, Hydrology, Water Resources
Soil Science

Publication Identifiers

DOI: https://doi.org/10.1029/2020JG005763

URI (permanent link to this page)

https://res.slu.se/id/publ/108294