Widespread occurrence of natural halogenated organics among temperate marine infauna

Despite the global prevalence of marine sedimentary habitats, the potential for chemically mediated ecological interactions within these assemblages r emains poorly known. Using GC/MS, we examined methanol extracts of worm, mo llusc, and crustacean macroinfauna from 2 local intertidal sandflat communi ties for volatile organohalogens, a common, often bioactive class of second ary metabolites from marine organisms. Halogenated compounds were newly ide ntified from 11 common polychaete species in the families Capitellidae, Cha etopteridae, Cirratulidae, Glyceridae, Pectinariidae and Spionidae. Tentati ve structures of these halometabolites are proposed based on GC/MS data. Th e represented chemical das ses included aromatic mono - and dibrominated hy droxyphenylpropanoids, nitrogen-containing bromoalkylpyrroles, as well as b rominated and chlorinated hydrocarbons and sulfides. Among the molluscs, on ly Terebra dislacata (Prosobranchia) contained an organohalogen compound (2 ,6-dibromophenol), which is likely derived from its diet of hemichordate wo rms. Volatile haloorganics were not found in amphipod and nemertean taxa. P ossession of these compounds was not a function of any particular phylum, s ize categorization, or trophic mode, although hemichordates and all Capitel lid and Spionid polychaetes collected at these sites invariably contained h alocompounds. Most (40 of ca 54 taxa) of the numerically dominant macroinfa unal taxa at these 2 sites were examined in this survey; of these, 43 % con tained halometabolites, including the broadly distributed species Mediomast us ambiseta, Heteromastus filiformis, Streblospio benedicti, Tharyx marioni , and Saccoglossus kowalevskii. Thus, the potential for widespread occurren ce of halogenated compounds among infauna is great. The presence of organoh alogens in many common and abundant polychaete species suggests a general b iological significance for these melabolites, a result of potential interes t to marine ecologists, toxicologists and environmental chemists.