ABSTRACT: Infauna greatly modify the sediments in which they live. One form of modification occurs via the organisms' secretions. In a number of families of Polychaeta and Hemichordata, the worms' secretions include halogenated 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 and observed the responses of recently settled juveniles of 2 bivalve and 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 experimentally contaminated with bromophenols, while all the bivalve juveniles burrowed into the control sediments. The arenicolid polychaete juveniles burrowed into the experimentally contaminated sediments, but the 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 effect on acceptance of the sediment by recently settled juveniles of all 3 species. These results are consistent with the concept of such secretions determining the composition of assemblages in areas with biogenic producers of haloaromatic compounds.

KEY WORDS: Recruitment · Polychaete · Bivalve · Settlement · Cue · Bromophenol · Rejection · Haloaromatic

Published in MEPS Vol. 157 (1997) on October 16
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 1997