Comparison of water chemistry in an artificial system and in coastal underwater Mexican caves

Kallmeyer, DE; Carpenter, JH

Northern Kentucky Univ., Dep. Biol. Sci., Highland Heights, KY 41099-0400, USA

Conference 2. International Conference on Groundwater Ecology, Atlanta, GA (USA), 27-30 Mar 1994 Stanford, JA; Valett, HM (eds)

PROCEEDINGS OF THE SECOND INTERNATIONAL CONFERENCE ON GROUND WATER ECOLOGY., AMERICAN WATER RESOURCES ASSOCIATION, 950 HERNDON PKWY, STE 300, HERNDON, VA (USA), 1994, pp. 77-84, ISBN 1-882132-28-9

AMERICAN WATER RESOURCES ASSOCIATION, 950 HERNDON PKWY, STE 300, HERNDON, VA (USA)

Interactions of temperature, density/salinity, pH, and solubility of carbon dioxide and calcium were studied in both an artificial freshwater/saltwater system and in coastal underwater caves on the Yucatan Peninsula, Quintana Roo, Mexico. These caves are composed of porous limestone and contain an upper freshwater layer and lower saltwater layer that mix to form a halocline. A clear plastic column was constructed to develop an artificial shallow halocline. In both the column and caves a correlation was established between carbon dioxide and pH. Generally, freshwater held more carbon dioxide than did saltwater. When samples were removed from the stable cave environment, there were significant changes in water chemistry associated with decreases in pressure: rapid decreases in dissolved carbon dioxide, increases in pH, and heavy precipitation of calcium carbonate. These changes affected some cave organisms so strongly that they did not survive outside the cave environment for more than a few days.