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1D - Soil and Sediment Contamination (TUP/17) Effect of benthic organisms (a polychaete and an echinoderm) on sediment-associated polycyclic aromatic carbon. Selck, Henriette1, Palmqvist, Annemette1, Granberg, Marie2, Forbes, Valery1, 1 Dept. of Life Sciences and Chemistry, Roskilde University, Roskilde, Denmark2 Dept. of Marine Ecology, Göteborg University, KMRS, Fiskebäckskil, Sweden ABSTRACT- Sediment dwellers represent a variety of feeding behaviours and life histories, which can their exposure to contaminants as well as the effect they have on sediment-associated contaminant fate. Infaunal deposit-feeding organisms, such as the polychaete, Capitella sp. I, burrow through sediment and obtain food from ingested particles in the top few centimeters of the sediment surface while depositing fecal pellets on the sediment surface. In contrast, the infaunal facultative deposit-feeding brittle star Amphiura filiformis lives with its body buried in the sediment (depth: 4-5 cm) and one or several arms raised into the water column when suspension feeding or lying on the sediment surface when deposit-feeding. We examined the effect of Capitella sp. I and Amphiura filiformis on removal / breakdown of the sediment-associated polycyclic aromatic hydrocarbon, fluoranthene (Flu). Sediment samples were extracted into 4 fractions: parent Flu (untransformed), polar- (phase I products), aqueous- (phase II products) Flu metabolites, and tissue residue Flu (unextractable). Capitella sp. I significantly enhanced removal of Flu from the sediment, which primarily was due to the production and excretion of water-soluble metabolites and to a lesser extent due to flushing. A. filiformis enhanced the downward transport of Flu from the surface sediment to deeper layers by burrow building, and altered (either directly or indirectly) the distribution of total Flu between parent and metabolites such that the metabolites constituted a higher percentage compared to parent Flu in the burrows. Thus, our results stress that bioturbation produced by these two organisms disrupts any equilibrium established by sediment-associated contaminants, affecting bioavailability not only to the deposit-feeders themselves, but potentially to all biota in the reworking zone. Key words: Polychaete, Echinoderm, PAH, sediment |
