Ecological status and type of alteration determine the C-balance and climate change mitigation capacity of Mediterranean inland saline shallow lakes.

Saline shallow lakes may play an important role in carbon exchange with the atmosphere, but their alteration may change carbon balance and greenhouse gas emissions patterns. This study investigated the relationship between carbon metabolic processes and environmental factors, focusing on alterations in salinity, hydroperiod length, and trophic status. The results revealed that disruptions to natural salinity patterns, driven by hydrological changes and ecological degradation, enhanced carbon greenhouse gas emitting metabolisms. In contrast, well-preserved lakes demonstrated significantly higher carbon retention and climate mitigation capacities (-188 ± 412 g C m yr) compared to lakes with hydrological and trophic disturbances (-30 ± 141 g C m yr). These findings emphasize the relevance of the metabolic activity of saline shallow lakes and highlight the need for targeted management and restoration efforts to maximize their climate regulation potential. The insights gained from this study may also be applicable to similar ecosystems in other regions.