MEPS 629:19-42 (2019)  -  DOI: https://doi.org/10.3354/meps13101

ABSTRACT: Cold seeps are locations where seafloor communities are influenced by the seepage of methane and other reduced compounds from the seabed. We examined macro-infaunal benthos through community analysis and trophic structure using stable isotope analysis at 3 seep locations in the Barents Sea. These seeps were characterized by high densities of the chemosymbiotic polychaetes Siboglinidae, clade Frenulata (up to 32120 ind. m^-2), and thyasirid bivalves, Mendicula cf. pygmaea (up to 4770 ind. m^-2). We detected low δ¹³C signatures in chemosymbiotic polychaetes and in 3 species of omnivorous/predatory polychaetes. These δ¹³C signatures indicate the input of chemosynthesis-based carbon (CBC) into the food web. Applying a 2-source mixing model, we demonstrated that 28-41% of the nutrition of non-chemosymbiotic polychaetes originates from CBC. We also documented large community variations and small-scale variability within and among the investigated seeps, showing that the impact of seepage on faunal community structure transcends geographic boundaries within the Barents Sea. Moreover, aggregations of heterotrophic macro- and megafauna associated with characteristic seep features (microbial mats, carbonate outcrops, and chemosymbiotic worm-tufts) add 3-dimensional structure and habitat complexity to the seafloor. Cold seeps contribute to the hydrocarbon-derived chemoautotrophy component of these ecosystems and to habitat complexity. These characteristics make the cold seeps of potential high ecological relevance in the functioning of the larger Arctic-Barents Sea ecosystem.

KEY WORDS: Cold seeps · Benthos · Methane · Trophic structure · Stable isotopes · Barents Sea · Svalbard

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Cite this article as: Åström EKL, Carroll ML, Sen A, Niemann H, Ambrose WG Jr, Lehmann MF, Carroll J (2019) Chemosynthesis influences food web and community structure in high-Arctic benthos. Mar Ecol Prog Ser 629:19-42. https://doi.org/10.3354/meps13101 Export citation Share:    Facebook - - linkedIn