1Institute of Chemistry and Biology of the Marine Environment, 26111 Oldenburg, Germany.
2Cardiff School of Biosciences, Cardiff University, Wales, UK.
Volatile organic substances (VOS) in the volatility range between n-undecane and n-heptadecane were derived from crude oil (EKO-FISK, North Sea) and their effects were studied on the polychaete species, Platynereis dumerilii. In behavioral bioassays less then 10 ng VOS samples induced ripe male to perform their characteristic spawning behavior and gamete release without presence of females. Active VOS-fractions derived from distillation were separated by liquid chromatography (LC) in alkanes, aromatic compounds and heteroatomic compounds (N, S & O). Active fractions were separated by gaschromatography. Single components were recondensed in acetone by peak-trapping, identified by coupled GC-MS and verified by synthesis. The analysis of fractions, which induced sperm release, revealed mononuclear aromatic hydrocarbons. The alkylated benzene with the highest potentiality was identified as p-butyl-methylbenzene. In seawater 3.8 nmol L-1 of synthetic p-butyl - methylbenzene induced sperm release of 70% within 2 minutes. Other benzenes activated up to 80% of assayed males to swim twice as fast as control. LC-fractions of distillates in the range between dodecane and heptadecane also induced characteristic swarming behaviour as well as spawning of male nereids. Analysis of these fractions revealed unidentified isomers of higher alkylated benzenes as bioactive compounds. Fractions among dodecane and tetradecane caused irreversible paralysis of males. Although alkylated benzene-rich LC-fractions induced spawning.