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Un ciclo microbiano de arsénico en un ambiente extremo y saturado de sal
Ronald S Oremland1, Thomas R Kulp, Jodi Switzer Blum
1U.S. Geological Survey, ms 480, 345 Middlefield Road, Menlo Park, CA 94025, USA. roremlan@usgs.gov
Science (New York, N.Y.)
|May 28, 2005
Resumen
El lago Searles es el lago Searles.
Área de la Ciencia:
- Ciencias ambientales Ciencias ambientales.
- La geoquímica es la geoquímica.
- Microbiología Microbiología.
Sus antecedentes:
- El lago Searles contiene salmueras alcalinas ricas en arsénico.
- La especiación del arsénico varía con la profundidad del sedimento, desde el arsenato [As(V) ] hasta la arsenita [As(III) ].
Objetivo del estudio:
- Investigar el ciclo biogeoquímico del arsénico en el lago Searles.
- Identificar las funciones microbianas en las transformaciones del arsénico.
Principales métodos:
- Incubación de lodos de sedimentos anóxicos y aeróbicos.
- Medición de la especiación del arsénico y la actividad microbiana.
- Aislamiento y caracterización de las bacterias que respiran arsénico.
Principales resultados:
- La actividad disimilatoria de la As(V) -reductasa fue estimulada por H2 o sulfuro en suspensiones anóxicas.
- La actividad de la AS (III) -oxidasa fue rápida en los lodos aeróbicos.
- Se aisló una bacteria anaeróbica, haloalcalifílica, que utilizaba la respiración As(V).
Conclusiones:
- En el lago Searles existe un ciclo biogeoquímico completo de arsénico.
- Los donantes de electrones inorgánicos contribuyen a impulsar este ciclo.
- Los procesos microbianos son clave para la transformación del arsénico en este entorno.
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