The Aigüestortes i Estany de Sant Maurici National Park is characterised by the wide diversity of aquatic ecosystems located here. There are more than 200 lakes within its boundaries, a fact that makes the Park the most important alpine lacustrine area of Europe. Since its beginnings, the LOOP has been in a close relationship with the Park, where part of its research has taken place. Since 2004, the LOOP carries out a monitoring programme in several lakes and streams of the Park. The LOOP is a founder member of the long term ecological research node LTER-Aigüestortes.