New hydrochemical and isotopic data in the karstic spring of Maro (Nerja, Málaga).Considerations on the origin of solutes and on the influence of the vadose zone ventilation

摘要

The previously stated model concerning the behaviour of the karstic spring of Maro is corroborated with new data from the 2004-2014 period.Sulphate isotopes allow linking the origin of solutes with the dissolution of Mesozoic gypsum. Other hydrochemical data (pH, DO) suggest the association of the spring with relatively large and well-ventilated karstic conduits in the vadose zone of the carbonate aquifer drained by the spring. During the winter season, such conduits could be affected by pressure or temperaturedriven high-PCO2 airflows that may be responsible for local decreases in the pH of the spring water