Erik Smedberg

Hydrological alterations with river damming in northern Sweden: Implications for weathering and river biogeochemistry

Hydrological alterations with river damming in northern Sweden : Implications for weathering and river biogeochemistry

Nitrogen flows from European regional watersheds to coastal marine waters

Approaches A comprehensive evaluation of net anthropogenic inputs of reactive nitrogen (NANI) through atmospheric deposition, crop N fi xation, • fertiliser use and import of food and feed has been carried out for all European watersheds. A database on N, P and Si fl uxes delivered at the basin outlets has been assembled. A number of modelling approaches based on either statistical regression analysis or mechanistic description of the processes involved • in nitrogen transfer and transformations have been developed for relating N inputs to watersheds to outputs into coastal marine ecosystems.

Modeling hydrology and silicon‐carbon interactions in taiga and tundra biomes from a landscape perspective: Implications for global warming feedbacks

Modelling hydrology and silicon-carbon interactions in taiga and tundra biomes from a landscape perspective : Implications for global warming feedbacks

Landscape elements and river chemistry as affected by river regulation – a 3-D perspective

We tested the hypothesis whether individual land classes within a river catchment contribute equally to river loading with dissolved constituents or whether some land classes act as “hot spots” to river loading and if so, are these land classes especially affected by hydrological alterations. The amount of land covered by forests and wetlands and the average soil depth (throughout this paper soil refers to everything overlying bedrock i.e. regolith) of a river catchment explain 58–93% of the variability in total organic carbon (TOC) and dissolved silicate (DSi) concentrations for 22 river catchments in Northern Sweden. For the heavily regulated Lulëalven, with 7 studied sub-catchments, only 3% of the headwater areas have been inundated by reservoirs, some 10% of the soils and aggregated forest and wetland areas have been lost due to damming and further hydrological alteration such as bypassing entire sub-catchments by headrace tunnels. However, looking at individual forest classes, our estimates indicate that some 37% of the deciduous forests have been inundated by the four major reservoirs built in the Lulëalven headwaters. These deciduous forest and wetlands formerly growing on top of alluvial deposits along the river corridors forming the riparian zone play a vital role in loading river water with dissolved constituents, especially DSi. A digital elevation model draped with land classes and soil depths which highlights that topography of various land classes acting as hot spots is critical in determining water residence time in soils and biogeochemical fluxes. Thus, headwater areas of the Lule älven appear to be most sensitive to hydrological alterations due to the thin soil cover (on average 2.7–4.5 m) and only patchy appearance of forest and wetlands that were significantly perturbed. Hydrological alterCorrespondence to: E. Smedberg (erik@mbox.su.se) ations of these relatively small headwater areas significantly impacts downstream flux of dissolved constituents and their delivery to receiving water bodies.