The works mentioned so far were not intended to be a true monitoring. However, they supposed the basis to set the framework of a posterior monitoring of the biogeochemistry of alpine waters as indicators of global change and, though intermittently, they provided the first time series of environmentally relevant data. By the early 2000’s, the idea of maintaining these series and a regular, long term environmental monitoring programme in the Pyrenees took off. At the same time, part of the researchers of the team, which had been until then composed exclusively of members of the Department of Ecology of the University of Barcelona, moved to the Center for Advanced Studies of Blanes (CEAB-CSIC). However the team kept operationally together, and became a sub-unit of the mixed Limnology Group under the denomination of the LOOP. In adition, the LOOP has been formally recognised by CEAB as one of its Observational Facilities.