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.
In northern Sweden, forestry and reindeer husbandry overlap spatially and judicially. To mitigate conflicting objectives regarding land use, the concept of " samråd" has been introduced as a form of institutional arrangement of environmental politics. This study
explores how stakeholders have interpreted this concept and corresponding processes from its first introduction in 1923 to 2019. Language, including the cartographic language, is regarded as a mean for argumentation. Results show that the understandings and expectations of samråd
differ among actors in terms of procedure, issues, efficiency and outcomes. As compared to the lexical definition and understanding, the samråd practice has merely become an instrument for information exchange before decisions are made, rather than a functional arrangement for
conflict mitigation. This ambiguity is in parallel to a deregulated forest policy and a watered-down meaning of samråd in public administration. However, the transformative potential of participatory mapping suggests a new way of thinking about power relations in land use matters
within the framework of samråd.
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.