Effects of Organic Enrichment and Burrowing Activity of the Polychaete Neries Diversicolor on the Fate of Tetrachlorobiphenyl in Marine Sediments

Abstract

Abstract-The effects of organic enrichment and burrowing activity of the infaunal polychaete Nereis (Hediste) diversicolor on the distribution of 14 C-3,3Ј,4,4Ј-tetrachlorobiphenyl (TCB) were studied in an experimental benthic system. Organic enrichment of the sediment was provided by a mixture of the diatom Skeletonema costatum and the sea lettuce Ulva lactuca. Organic matter and TCB were both initially added to a surface sediment layer of the microcosms. A factorial design with organic enrichment (control vs enriched) and bioturbation (presence or absence of N. diversicolor) as fixed factors and concentration of TCB in sediment, water, and biota as dependent variables allowed us to test the four combinations. Release of TCB from the sediment to the water column was measured in the outflowing water of the aquaria. After 28 d of exposure, TCB concentrations were measured in animals, feces, sediment cores, burrows, sediment surface, and in sulfur bacteria mats. Both bioturbation and organic enrichment enhanced the release of TCB from the sediment to the water column. The greatest effect was caused by the combination of the two factors, which increased release rates by 280% compared with controls. No general downward transport and vertical redistribution of TCB in the sediment were observed. However, TCB concentrations were significantly higher in the burrow linings of the worms than in the bulk sediment. Increased TCB accumulation by the animals was observed following organic enrichment, which was considered to be the result of selective feeding on TOC-rich contaminated food particles. The organic enrichment also stimulated the production of sulfur bacteria mats, which were found to accumulate high TCB concentrations. Our results contradict those of several other studies that have reported a reduced bioavailability of organic contaminants with increasing sedimentary organic carbon content. Our study suggests that the quality of the organic matter should be considered in the evaluation of exposure in benthic organisms.

Effects of settling organic matter on the bioaccumulation of cadmium and BDE-99 by Baltic Sea benthic invertebrates

“…This is in agreement with previous studies, which have shown that assimilation efficiency and bioaccumulation of cadmium is greater from phytoplankton than from sediment (Griscom et al, 2002b) and wood fibers (Maloney, 1996). Similarly, several HOCs have been observed to exhibit enhanced bioaccumulation when associated with labile OM (Gunnarsson et al, 1999a(Gunnarsson et al, , 1999b. Since all species studied in this experiment can be assumed to have a preference for labile algae compared to more refractory food sources (Christensen and Kanneworff, 1985;Wheatcroft, 1989, Byrén et al, 2002), the higher BAFs for both…”

Effects of sediment organic matter quality on bioaccumulation, degradation, and distribution of pyrene in two macrofaunal species and their surrounding sediment

“…than with refractory lignin. Enrichment with high quality organic matter (OM) has been reported to stimulate accumulation of sediment associated PCB and PAH in various sediment dwelling marine invertebrates including A. filiformis and N. diversicolor (Gunnarsson, Schaanning, Hylland, Sköld, Eriksen, Berge et al, 1996, Gunnarsson et al, 1999b, Gunnarsson & Sköld, 1999. In all of these studies, however, enriched treatments contained more total organic carbon (TOC) than controls, thus confounding effects of SOM quality and quantity and complicating mechanistic interpretations.…”

“…Pyrene is a particle reactive compound , log K OW between 4.50 and 5.32 (Meador et al, 1995), and its distribution is thus highly dependent on forces affecting particle mixing, such as macrofaunal feeding and burrowing. Species-specific differences in bioturbation behaviour often appear to leave finger prints in the distribution of contaminants in the sediment (Holmer et al, 1997, Kure & Forbes, 1997, Gunnarsson et al, 1999a, Gunnarsson et al, 1999b, Sandnes, Forbes, Hansen & Sandnes, 2000. N. diversicolor build, and continuously re-route, extensive burrow galleries (Davey, 1994), while A. filiformis, although sometimes observed to be highly mobile, construct only as much burrow needed for keeping disks buried at ~5 cm depth with 2-4 arms protruding from the sediment for feeding (Woodley, 1975, Jonsson, Broman, Gunnarsson, Lagergren, Larsson, Ohlsson et al, 1997 ( Fig.…”

“…Such physiological response due to changes in food value is likely also to affect the absorption, metabolism and general fate of sediment associated contaminants. E xperimental enrichment with high quality SOM has previously been reported to stimulate the accumulation of sediment associated PCBs and PAHs in various marine invertebrates (Gunnarsson, Granberg, Nilsson, Rosenberg & Hellman, 1999a, Gunnarsson, Hollertz & Rosenberg, 1999b, Gunnarsson & Sköld, 1999, Granberg & Forbes, 2006, while effects of SOM quality on contaminant metabolism and toxicity are largely unexplored. Furthermore, the stimulating effect of increased SOM quality on general microbial mineralization is well documented (Graf, Schulz, Peinert & Meyer-Reil, 1983, 6 Meyer-Reil, 1983, while information is scarce on its effects on the microbial degradation of organic contaminants in sediments.…”

Relative importance of macrofaunal burrows for the microbial mineralization of pyrene in marine sediments: impact of macrofaunal species and organic matter quality

“…A. filiformis has further been shown to concentrate particle reactive contaminants such as fluoranthene and tetrachlorobiphenyl (TCB) in the burrow sediment, with TCB concentrations an order of magnitude higher in burrows compared to the surrounding bulk sediment (Gunnarsson et al 1999a, Selck et al 2004. N. diversicolor have been shown to do the same, however, to a lesser extent (Gunnarsson et al 1999b). The lower TCB concentrations observed in N. diversicolor burrows may result from contaminant dilution as the wall surface area of a single N. diversicolor burrow is several times larger than that of a single A. filiformis burrow.…”