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New Insights Into Legacy Phosphorus From Fractionation of Streambed Sediment
Author(s) -
Lannergård Emma E.,
AgstamNorlin Oskar,
Huser Brian J.,
Sandström Sara,
Rakovic Jelena,
Futter Martyn N.
Publication year - 2020
Publication title -
journal of geophysical research: biogeosciences
Language(s) - English
Resource type - Journals
eISSN - 2169-8961
pISSN - 2169-8953
DOI - 10.1029/2020jg005763
Subject(s) - sediment , streams , drainage basin , hydrology (agriculture) , eutrophication , ditch , environmental science , phosphorus , soil water , organic matter , geology , nutrient , soil science , ecology , geomorphology , chemistry , geography , computer network , cartography , geotechnical engineering , organic chemistry , computer science , biology
Streambed and lake sediment was studied in Sävjaån, 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.