The acceleration of biogeochemical cycles in high mountain areas during the Anthropocene

The increase in atmospheric carbon dioxide, the greater deposition of assimilable nitrogen and phosphorus compounds, and warming that extends the vegetative period in cold regions suggest an acceleration of biogeochemical processes in remote cold areas not directly affected by human activity. The alpine zones of high mountains are likely among them. However, current monitoring lacks sufficient temporal perspective, as these changes likely began around the mid-20th century.

The study of sedimentary records from alpine lakes offers an alternative to the absence of long-term monitoring. To explore potential indications of this acceleration in biogeochemical cycles, sediment cores from three lakes in a basin with minimal livestock influence within Aigüestortes i Estany de Sant Maurici National Park were analyzed. The results reveal an abrupt shift in sediment composition beginning in the mid-20th century, characterized by an increase in organic content, a decline in complex organic molecules, and a probable acceleration of the nitrogen cycle due to greater nitrogen availability. These changes are strongly reflected in the isotopic composition of carbon and nitrogen, as well as in the bacterial communities associated with the sediments.

These findings reinforce the role of National Parks as exceptional sites for monitoring and assessing the impact of global change

Duration: December 2020 - December 2023

Funding Agency: Organismo Autónomo de Parques Nacionales

LOOP participants: Marisol Felip, Jordi Catalan, Lluís Camarero

Coordinator: Jordi Catalan

Collaborators: Antonio Martínez Cortizas, Meritxell Batalla, Sergi Pla

Participant institutions: CREAF, CEAB-CSIC, USC