Inhibition of microbial activity in marine sediments by a bromophenol from a hemichordate

Abstract

Allelochemicals, a class of organic compounds, affect succession, competition, predation and other interactions between organisms^1–3. Bromophenols, a member of this class, are found in marine algae and invertebrates, particularly annelids, phoronids and hemi-chordates^4,5. Bromophenols are toxins with bacteriocidal properties^6–9. Here I report inhibition of microbial activity in marine sediments by the common bromophenol, 2,4-dibromophenol (DBP), from the hemichordate Saccoglossus kowalewskii and demonstrate that anaerobic microbial metabolism in sediments is relatively unaffected by DBP whereas aerobic metabolism is particularly sensitive. These data, together with observations of the distributions of DBP and burrow-wall chemistry, suggest that secretion of DBP inhibits the aerobic microbial degradation of the burrow-wall mucous lining or alters local biogeochemistry. Thus, bromophenols may be targeted against higher organisms with which S. kowalewskii competes as well as against microorganisms.