Lake Redon (formerly called Redó) has been the main research site of LOOP since 1984 and is one of the most studied alpine lakes in the world. Located in the Pyrenees at 2240 m altitude, it has been continuously monitored for nearly 30 years, with extensive studies on its limnology, climate interactions, and environmental changes. Research there has advanced understanding of global change, pollution, and ecosystem dynamics over the past 10,000 years.

The Pleta dels Molières peatland, located in the central Pyrenees near Vielha, is one of the region’s most representative acidic wetlands. Formed on granite at 1,720 m altitude, it hosts diverse peat-forming habitats and plays a key role in regulating carbon, nutrient, and water cycles. Its unique hydrology makes it a valuable site for studying how mountain peatlands respond to environmental change.

The Aigüestortes i Estany de Sant Maurici National Park, the only national park in Catalonia, is one of the best-preserved alpine ecosystems in the Iberian Peninsula, with over 200 lakes and great biodiversity. LOOP has conducted long-term ecological research there since 2004, focusing on the Sant Nicolau Valley—an experimental site for studying hydrology, biogeochemistry, and climate change impacts in high-mountain environments through advanced sensor networks and water monitoring programmes.

The Pyrenees Lake District, with over a thousand alpine lakes spanning diverse geological and climatic zones, is one of Europe’s richest mountain lake regions. Its varied conditions make it a natural laboratory for studying how environmental and human factors shape alpine ecosystems. LOOP has surveyed these lakes since 1987, building a database of over 500 sites to track long-term ecological changes.