6th Annual ARCUS Award for Arctic Research Excellence

Honorable Mention Life Science

Submitted by		Robin Brinkmeyer
Authors		Robin Brinkmeyer
Category		Life Science
Title		Oxidation and Utilization of Dimethylsulfide and Dibromomethane by Bacteria in Arctic Sea-ice
Affiliation		Biological Oceanography, University of Bremen, Bremerhaven, Germany

Abstract

Algal-rich sea ice collected in the Arctic Ocean during the F.S. Polarstern ARKXVI/2 expedition was incubated with ¹⁴C labeled- dimethylsulfide and dibromomethane, respectively, over several days. Oxidation of these compounds by bacteria was measurable. The same sample was enriched with unlabeled dimethylsulfide, dibromomethane and methane as the sole carbon sources. Clone sequences from these enrichment cultures revealed diverse consortia including bacteria closely related to an obligate methylotroph, Methylophaga sp. Application of MICRO-FISH indicates that only certain members of the gamma subclass of Proteobacteria incorporate dimethylsulfide as cell material.