title: The polychaete worm Nereis diversicolor increases mercury lability and methylation in intertidal mudflats.
abstract: The polychaete worm Nereis diversicolor engineers its environment by creating oxygenated burrows in anoxic intertidal sediments. The authors carried out a laboratory microcosm experiment to test the impact of polychaete burrowing and feeding activity on the lability and methylation of mercury in sediments from the Bay of Fundy, Canada. The concentration of labile inorganic mercury and methylmercury in burrow walls was elevated compared to worm-free sediments. Mucus secretions and organic detritus in worm burrows increased labile mercury concentrations. Worms decreased sulfide concentrations, which increased Hg bioavailability to sulfate-reducing bacteria and increased methylmercury concentrations in burrow linings. Because the walls of polychaete burrows have a greater interaction with organisms, and the overlying water, the concentrations of mercury and methylmercury they contain is more toxicologically relevant to the base of a coastal food web than bulk samples. The authors recommend that researchers examining Hg in marine environments account for sediment dwelling invertebrate activity to more fully assess mercury bioavailability.
authors: Department of Earth & Environmental Science, K.C. Irving Environmental Science Center, Acadia University, Wolfville, Nova Scotia, Canada.
authors: Tom
authors: T
authors: Sizmur
authors: João
authors: J
authors: Canário
authors: Samuel
authors: S
authors: Edmonds
authors: Adam
authors: A
authors: Godfrey
authors: Nelson J
authors: NJ
authors: O'Driscoll
mesh_terms: D000818:Animals; D002170:Canada; D003901:Desulfovibrio / Q000187:drug effects; D020387:Food Chain; D019015:Geologic Sediments / Q000737:chemistry* / Q000382:microbiology; D008628:Mercury / Q000378:metabolism / Q000633:toxicity*; D008745:Methylation; D008767:Methylmercury Compounds / Q000378:metabolism / Q000633:toxicity*; D011077:Polychaeta / Q000502:physiology*; D053833:Wetlands
chemical_list: D008767:Methylmercury Compounds; D008628:Mercury
keywords: Bioavailability; Hg; Methylmercury; Redox; Sulfur