WP 2: Regionalisation of lake chemistry
Targets
Lead Contractor
Lead Partners
Task 2.1
Task 2.2
Task 2.3
Task 2.4
Targets
The water chemistry of mountain lakes is influenced mainly by
catchment bedrock and soils and by atmospheric deposition and varies
significantly across Europe. In this workpackage we relate
atmospheric deposition and catchment soils to water chemistry,
produce a chemical classification of lakes, and generate data that
allow the MAGIC model to be used for scenario testing of sulphur and
nitrogen reductions at the regional scale.
Task 2.1.: Extrapolation of chemical deposition
Chemical deposition has been recently measured on site for a
number of remote lakes in Europe. We will use these data and EMEP
data to extrapolate chemical deposition to all Lake
Districts. Deposition to individual sites will be obtained by
interpolating data from the four closest EMEP surrounding grid
cells (50 x 50 km) with inverse square distance weighting models,
and correcting the interpolation using records of measured
deposition at our Experimental sites.
Task 2.2.: Regionalisation of soil properties relevant to
mountain lake water chemistry
Although soils are poorly developed in mountain lake
catchments it is necessary to characterise catchment soils in
order to calibrate models. We will select a maximum of 3 lake
catchments from each Lake District for detailed sampling and
analysis. We will define the main lithological and vegetation
units that most strongly correlate with the different soil types
present and then characterise each soil type according to depth,
bulk density, cation exchange capacity (CEC), base saturation (BS)
and carbon-nitrogen (C-N) content. A system for classifying soils
within catchments will thereby be obtained, and this will in turn
enable the principal data required by the models (CEC, BS and C-N)
to be generated for each site.
Task 2.3.: Chemical classification and empirical
regionalisation
Water chemistry data already available, together with new
data will be used to establish a lake classification both for
individual Lake Districts and for the whole of Europe. This
procedure will allow the continuous range of variability to be
reduced to a few classes and will facilitate regionalisation
according to catchment attributes (WP
6) and enable the application of biogeochemical models such
as MAGIC7 and SMART.
Task 2.4.: Regionalisation of process-based chemical models
Process-based models, such as MAGIC that simulate water
runoff chemistry, are particularly suitable for forecasting
changes in lake-water chemistry in mountain regions. The MAGIC7
model has already been tested at some mountain lake sites, and we
will use these previous calibrations for regionalisation trials in
Central and Southern Norway, Scotland, the Pyrenees and the Tatra
Mountains. Of the two regionalisation techniques that have been
previously developed we will use the site-specific approach which
involves the calibration of MAGIC7 to each lake/catchment data
set individually, followed by the aggregation of the results to
the regional scale. This technique allows for GIS mapping of the
predicted results within each region. Validation of the predictive
capacity of the models will be tested using palaeolimnological
and, where available, instrumental data. Palaeolimnological data
covering the last 200 years are available from all Experimental
sites. However, new cores (one per Lake District) will be
analysed for a site in Greenland and for sites in the Retezat and
Rila Mountains.
Lead Contractor
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NIVA - Norwegian Water
Research Institute, Oslo, Norway
Lead Partners
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UB-DE - Ecology Department, University of Barcelona, Spain
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HBI-ASCR - Hydrobiological
Institute, Academy of Sciences of the Czech Republic, Ceske
Budjovice, Czech Republic
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