MEPS 179:241-246 (1999)  -  doi:10.3354/meps179241

ABSTRACT: Many marine infaunal hemichordates and polychaetes produce volatile halogenated secondary metabolites, including several brominated aromatic compounds. These compounds have been suggested to have antimicrobial activity. However, the impact of added bromometabolites on microbial activities in undisturbed sediments has not been assessed. This study examines the effects of a common bromometabolite, 4-bromophenol, on substrate respiration and assimilation by undisturbed sediment bacterial communities. Intact sediment cores were collected from a site inhabited by the bromophenol producing capitellid polychaete Notomastus lobatus and from a similar site having no bromometabolite producing infauna. These cores were injected with a radiolabeled substrate (acetate or glucose) and varying levels of 4-bromophenol, then incubated at in situ temperature. Rates of respiration and assimilation of the substrates at levels of 4-bromophenol ranging from ambient to 10 µg g^-1 (dry weight) sediment were determined. No significant inhibition of respiration or assimilation of either substrate was observed in samples from either location, even at 4-bromophenol levels 100x the ambient concentration in wormbed sediments. These data show that this naturally occurring bromoaromatic compound has no significant effect on community activity of sediment bacteria.

KEY WORDS: Bromophenols · Bromometabolites · Marine sediment · Bacterial activity