Yet the geographic scope of the LOOP spans beyond the local scale. Synoptic lake surveys conducted not only in the AESM National Park, but also in the whole Pyrenean range, have been the basis for developing a regional Pyrenean limnology. Moreover, the repeated surveys over time provide a view of the environmental changes at the regional scale. The data collection started by Prof. Margalef and coworkers survey in 1975 has been continued in the 1986 survey mentioned above, and subsequent surveys in the framework of several projects in 1994-95, 2000 and 2011, covering thus a multi-decadal period.