title: Dark carbon fixation: an important process in lake sediments.
abstract: Close to redox boundaries, dark carbon fixation by chemoautotrophic bacteria may be a large contributor to overall carbon fixation. Still, little is known about the relative importance of this process in lake systems, in spite the potentially high chemoautotrophic potential of lake sediments. We compared rates of dark carbon fixation, bacterial production and oxygen consumption in sediments from four Swedish boreal and seven tropical Brazilian lakes. Rates were highly variable and dark carbon fixation amounted up to 80% of the total heterotrophic bacterial production. The results indicate that non-photosynthetic carbon fixation can represent a substantial contribution to bacterial biomass production, especially in sediments with low organic matter content.
authors.affiliation: Department of Ecology, Institute of Biology, University Federal of Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: Santoro
authors.forename: David
authors.initials: D
authors.lastname: Bastviken
authors.forename: Cristian
authors.initials: C
authors.lastname: Gudasz
authors.forename: Lars
authors.initials: L
authors.lastname: Tranvik
authors.forename: Alex
authors.initials: A
authors.lastname: Enrich-Prast
mesh_terms: D018533:Biomass; D001938:Brazil; D002244:Carbon / Q000737:chemistry*; D057486:Carbon Cycle; D019015:Geologic Sediments / Q000737:chemistry*; D060106:Lakes; D010101:Oxygen Consumption; D013548:Sweden
chemical_list: D002244:Carbon