We have added the measurement of both stable and radio-isotopes to the routinary monitoring scheme in the Aigüestortes i Estany de Sant Maurici National Park, with the aims of:

1) Comparing the isotopic composition of water and several solutes in atmospheric deposition in the bottom and the highest areas of the Sant Nicolau valley.  

2) Carrying out solute mass-balances in three lakes at different altitude, to assess changes in the isotopic composition and infere which are the dominant biogeochemical processes within the lakes.

3) Examinating the fluxes of isotopes to and from the sediments in two lakes, using sediment traps and monitoring changes in the deepest zones of the lakes. Thermistor chains are installed in the lakes to monitor in detail stratification and mixing of the water column.

4) Measure the inputs of fine and coarse suspended matter in two lakes, and determine its isotopic composition. For this, drift traps are installed at the inlet and outlet of the lakes.

5) Modeling the transfer of radio-isotopes from the atmosphere to soil and snow cover, and from these to the lakes.