MICROBIAL BIOMASS AND COMMUNITY STRUCTURES IN THE BURROWS OF BROMOPHENOL PRODUCING AND NONPRODUCING MARINE WORMS AND SURROUNDING SEDIMENTS

Microbial biomass and community structures were determined in sediment s lining the burrows of 3 species of marine worms, and in nearby surfa ce and subsurface sediments, using ester-linked phospholipid fatty aci d (PLFA) analysis. The potential impact of biogenic bromophenols produ ced by 2 of these animals on burrow microbial communities was of parti cular interest. The burrow microbial communities were markedly differe nt from those of surrounding surface and subsurface sediments. Differe nces in microbial biomass were attributed to burrow structures, textur es of the burrow lining sediments, and organic carbon content. No sign ificant reduction of microbial biomass or of several distinctive signa ture PLFA was detected in bromophenol-contaminated burrows, when compa red to non-bromophenol-containing burrows. All 3 types of sediments (b urrow, surface, and subsurface) examined for each worm species were di stinct as determined by multivariate cluster analysis of PLFA profiles . Signature lipid biomarker PLFA for Gram-negative bacteria, Gram-posi tive bacteria, sulfate-reducing bacteria and anaerobes, and microeucar yotes were readily identified in burrow sediments from bromophenol pro ducing and non-producing worm.