A common and previously unknown ecological niche: the halorespiration of natural organochlorines in terrestrial soil and sediment

Abstract

The phylum <italic>Chloroflexi</italic> contains several isolated bacteria that have been found to dechlorinate a diverse array of halogenated anthropogenic chemicals. These bacteria use organohalogens, such as polychlorinated biphenyls and trichloroethene, as their terminal electron acceptors and are called halorespirers. While the distribution and role of halorespiring <italic>Chloroflexi</italic>, as well as halorespirers in other phyla such as the <italic>Firmicutes</italic>, have been relatively well characterized in contaminated systems and laboratory cultures, their distribution and role in uncontaminated terrestrial environments, where abundant natural organohalogens could function as potential electron acceptors, has not been studied. This dissertation focuses on the distribution and role of halorespiring <italic>Chloroflexi</italic> in uncontaminated environments and investigates the ability of natural organochlorines to serve as terminal electron acceptors for halorespiring organisms.