BIOGENIC BROMOPHENOLS AS NEGATIVE RECRUITMENT CUES

Infauna greatly modify the sediments in which they live. One form of m odification occurs via the organisms' secretions. In a number of famil ies of Polychaeta and Hemichordata, the worms' secretions include halo genated aromatic compounds such as bromophenols. To determine how the presence of such compounds affects juvenile infauna, we directly added synthetic bromophenols to natural sediments at field concentrations a nd observed the responses of recently settled juveniles of 2 bivalve a nd 1 polychaete species. In nature the bromophenols are secreted into sediments by a capitellid polychaete. A significant percentage of the bivalve juveniles (50 and 67%) did not burrow into the sediments exper imentally contaminated with bromophenols, while all the bivalve juveni les burrowed into the control sediments. The arenicolid polychaete juv eniles burrowed into the experimentally contaminated sediments, but th e rate of burrowing of these juveniles was significantly slower in the contaminated sediments than in the control sediments. The addition of bromophenols to sediments, therefore, had a significantly negative ef fect on acceptance of the sediment by recently settled juveniles of al l 3 species. These results are consistent with the concept of such sec retions determining the composition of assemblages in areas with bioge nic producers of haloaromatic compounds.