Microbial reductive dehalogenation in Antarctic melt pond sediments

• Published in: Antarctic Science
• Main Authors: Griffin, Benjamin M., Tiedje, James M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2007
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; Ross Island; McMurdo Ice Shelf; Bratina Island; Antarc*; Antarctic Science; Antarctica; Ice Shelf
• Online Access: http://dx.doi.org/10.1017/s0954102007000570; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102007000570

Abstract Due to its geographic isolation and relatively limited human impact, Antarctica is a promising location to study the eco-physiology of natural halogen cycles. Anaerobic sediments from Antarctic melt ponds on Ross Island and on the McMurdo Ice Shelf near Bratina Island were tested for activity of microbial reductive dehalogenation. Anaerobic enrichment cultures were established with potential electron donors and tetrachloroethene, trichloroethene, 2-bromophenol, 2-chlorophenol, 3-bromobenzoate, or 3-chlorobenozoate, as model halocarbon electron acceptors. Dechlorination of aromatic compounds was limited, whereas 2-bromophenol was debrominated in seven of the eight sediments and one site also showed debromination of 3-bromobenzoate. A most probable number estimate with 2-bromophenol at one site revealed 10 3 –10 4 cultivatable debrominators per gram of sediment (wet weight). Chloroethene dechlorination was slow and primarily produced trichloroethene from tetrachloroethene, although both cis- and trans- dichloroethene were detected in certain enrichments upon extended incubation. These results demonstrate the presence of reductive dehalogenating activity in anaerobic, Antarctic melt-pond sediments and expand the known metabolic diversity of Antarctic microorganisms.