摘要：Quantification of suspended sediment yield from rivers is essential to determining how land cover and land use affect water quality in fluvial ecosystems and erosion rates in catchment basins. In this study we used long-term (1967–2011) river-runoff and sedimentconcentration data to seek new insights into suspended sediment transport and its governing factors. We found that long-term suspended sediment concentrations and yield of very fine sediment (< 0.4–1.2 μm) are dependent on: (i) temporal changes in biogeochemical processes in catchment soils and fluvial systems, and (ii) temporal variations in metal humate colloid concentrations, especially in peat-covered catchments. The results also showed that the proportion of very fine sediment varies seasonally and can significantly affect transport rates in boreal rivers. Thus national monitoring activities should includeparameters describing the quality of suspended sediment (e.g. particle size range and losson-ignition) in order to provide information relevant to land management and ecological assessments in boreal rivers.
