Resumen de Caracterización microecológica del ambiente de formación de carbonatos de Ca y Mg en sedimentos actuales mediante microelectrodos (Laguna de Gallocanta, NE España)
Aránzazu Luzón Aguado, Alfonso Corzo Rodríguez, María José Mayayo Burillo, J.S. Van Bergeijk, María Pilar Mata Campo, Juan García de Lomas
In this paper we describe the physical-chemical properties of the water-sediment interface and themineralogical and microbiological features of the upper sediment layer in three subenvironments in Gallocanta Lake: central (GLC), marginal (GLM), and palustrine (GP). An increasing gradient insalinity and sulphate concentration is detected from the palustrine to the central lacustrine area. The type of carbonate occurring in each subenvironment seems to be related to water chemistry and the highest contents in Ca-Mg carbonates in GLC. In contrast; only Ca-carbonates have been identified in GP. The microbial communities inhabiting the upper sediment layer in each subenvironment differed both, in taxonomic composition and in relevant metabolic activities. The microbial community in GLC lacked photosynthetic capacity. In this environment there is no O ,production, and anoxic conditions are reached at 700 m depth; below this limit an increasing H2Sproduction has been detected. Microbial communities in GLM and GP presented photosyntheticcapacity and were able to oxygenate the upper sediment layer when exposed to light conditions.We propose that the Ca-Mg carbonates in Gallocanta Lake precipitate favoured by the anaerobicoxidation of organic carbon by dissimilatory sulphate reduction.
