Land and freshwater ecosystems are important reactors in Global Change; pollution and climate change affect biogeochemical functions, which feeds back on climate forcing and eutrophication through emissions to water and atmosphere. An interdisciplinary wa tershed project is proposed, focusing the release and ecological roles dissolved organic carbon (DOC) on its way from soil to the coast, and the release of greenhouse gases (GHG) to the atmosphere. The rationale for combining these phenomena in one projec t is the common spatial and temporal regulators in the landscape (geomorphology, hydrology, forest biomass and productivity), hence a common interest in tackling scaling issues by stratifying the landscape into homogenous response units (HRU).
In a refer ence watershed, novel high resolution remote sensing techniques will be used in combination with hydrological modeling, to delineate HRUs. The terrestrial "ground truth" will be investigated by field campaigns (hydrology, soil- and vegetation, gas fluxes, their isotope signatures, etc). The ultimate aim is to explore the options for adequate landscape stratification based on remote sensing, as a basis for upscaling estimates of DOC release and GHG flux/isotope-signatures. Ongoing measurements of DOC and c hemistry in the reference watershed will be continued and refined.
The project is divided into 5 work packages. WP1 will analyse databases for Nordic lakes to explore concentrations and mass transport of DOC, N, P and Si related to hydrology and watershed properties. WP2 and3 involves all partners in process-oriented studies of the reference watershed. WP4 will study loss rates and transformations of DOC in water (photo-oxidation and microbial) while WP5 will build on WP1-4 to construct an empirical model for a mass balance of C and flux of greenhouse gases from northern catchments in relation to catchment characteristics and climate, linking also the dependency of other key elements to the flux and fate of C.