The overall objectives of the project are: to establish a network of catchments within Europe, covering a range of environmental conditions (including pollution climates) representative of Europe, where a common baseline programme of research and more intensive process and/or mechanistic studies will be carried out; to develop, or modify existing process based models to assess and predict the response of catchment ecosystems to natural and anthropogenic perturbations; and to identify indicators of environmental change and damage at different hierarchical levels within catchments suitable for the analysis and prediction of the effects of natural and anthropogenic perturbations.
Each site will provide common data on atmospheric inputs and drainage water outputs, (the network comprises 17 groups of experimental catchments in 7 countries), plus basic site and environmental data. Data collection, sampling and chemical analysis of samples will be carried out using common protocols. A central database will be established at the University of Goettingen and each site will provide data to this data base in common formats.
The following process studies will be carried out in subsets of the catchments.
Weathering rates and processes: quantification of base cation production from mineral weathering in a range of rock and soil types.
Quantification of atmospheric inputs: quantification of total atmospheric inputs to catchments; comparison of available methods; and production of protocols for future studies.
Water pathways and residence times: quantification of the contribution of water from different sources to streams at varying flows, in a range of catchment types represented by the network.
Ion exchange and A1 mobilization: development of improved models of ion exchange and A1 mobilization and immobilization for incorporation in hydrochemical models.
Sulphate fluxes: improved models of the processes controlling sulphate retention and production in soil plant systems.
Nitrate fluxes: improved models of the processes controlling nitrate retention and production in soil plant systems.
Experimental manipulations at selected catchments to allow testing, and further development of the models will be carried out: additions of nitric acid (a Gardsjon subcatchment); removal of excess nitrate and sulphate from atmospheric inputs (a Gardsjon subcatchment); liming (a Llyn Brianne subcatchment); clearcuttings (a Waroneu subcatchment); clearance of understorey vegetation (a Filebres subcatchment); burning (a Mont Lozere subcatchment); and addition of ammonium sulphate (a Schluchsee subcatchment).
Existing hydrochemical models (MAGIC, BIRKENES, RAINS) will be applied at catchments from each site to test the models over a wide range of environmental conditions, to identify key controlling processes and weaknesses in the models. Existing hydrochemical models using data from the process studies and experimental manipulations combined with results from application of the existing models across the network will be modified and enhanced.
Empirical models linking hydrochemistry to aquatic biota, initially using data from catchments in the United Kingdom will be developed and using data from other catchments in the network.
Forest growth models and hydrochemical models will be linked and tested using data from clearcutting studies and the sites in the network showing signs of frost damage.
Critical loads for forest soil systems and surface waters will be calculated at each site. The validation of currently proposed critical loads using data on aquatic biota and vegetation growth and status will be achieved.
Funding Schemeundefined - undefined
AB9 2QJ Aberdeen
LA1 4YQ Lancaster /High Bantham
CF1 1XL Cardiff