The GCAN Webinar series presents Dr. José Gilberto Cardoso Mohedano, Investigador Titular A, Laboratorio de Modelado Ecológico and Estación del Carmen-ICML, UNAM. His talk “Hidden Carbon Sources: How Karst Geology Drives Extreme COz Variability in Mexico’s Largest Coastal Lagoon” focused on his research in the Yucatán Peninsula.
Karstic groundwater flowing through the limestone-rich Yucatán Peninsula delivers large amounts of dissolved carbon to Términos Lagoon, the largest tropical estuarine-lagoon system in the southern Gulf of Mexico. Measurements along river-to-coast transects during dry and rainy seasons revealed strong seasonal shifts: alkalinity and dissolved inorganic carbon were highest in the dry season, while CO? levels nearly doubled and pH dropped during the rainy season.
The Palizada River became an extreme CO? hotspot during the rainy season, reaching 4,000–8,000 µatm — far above typical river values and up to four times higher than the Mississippi-Atchafalaya system. These findings show that karst groundwater discharge and organic matter oxidation make the Yucatán Peninsula a major CO? source with important implications for Gulf carbon budgets and coastal acidification monitoring.
