Alteration and release of aliphatic compounds by the polychaete Nereis virens (Sars) experimentally fed with hydrocarbons

In the laboratory, marine worms were fed with a mixture of algae and severa l aliphatic hydrocarbons for 15 days. After ingestion by the worms, 34.9% o f hydrocarbons are found in the faeces and only 3.1% accumulated in the gut . The comparison between the initial mixture and the faeces shows that the worm's digestive process lead to changes in the distribution of the n-alkan e mixture. These changes are different from those only due to physical proc esses in the experimental conditions. In our experiment, no variation in th e distribution of hydrocarbons in faeces with time and no microbial hydroca rbon biodegradation were evidenced. Our results suggest that marine worm fe eding can substantially affect the fate of hydrocarbons in the sedimentary marine ecosystem by predominantly stimulating dissolution processes. (C) 20 01 Elsevier Science B.V. All rights reserved.