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Aquatic Microbial Ecology

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AME 36:271-284 (2004)  -  doi:10.3354/ame036271

Influence of bioturbation by three benthic infaunal species on microbial communities and biogeochemical processes in marine sediment

F. Mermillod-Blondin1,2,*, R. Rosenberg2, F. François-Carcaillet3,5, K. Norling2, L. Mauclaire4

1UMR-CNRS 5023, Laboratoire d¹Ecologie des Hydrosystèmes Fluviaux, Université Calude Bernard Lyon I, Domaine Scientifique de la Doua, 69622 Villeurbanne, France
2Department of Marine Ecology, Göteborg University, Kristineberg Marine Research Station, 45034 Fiskebäckskil, Sweden
3UMR-CNRS 7621, Laboratoire Arago, Université Paris VI, BP 44, 66651 Banyuls/Mer, France
4Swiss Federal Institute of Technology Zurich, Geological Institute, Sonneggstrasse 4, 8092, Zurich, Switzerland
5Present address: UMR-CNRS 5119 ŒEcosystèmes lagunaires¹, Université Montpellier II, Case 093, Place Eugène Bataillon, 34095 Montpellier cedex 05, France

ABSTRACT: Benthic invertebrates play a key role in the physical, chemical, and biological properties of the marine water-sediment interface. The influences of invertebrates on biogeochemical processes have mainly been attributed to their sediment reworking and bioirrigation activities. The aim of this study was to compare the influences of bioturbation activities by 3 dominant species of shallow water habitats (Cerastoderma edule, Corophium volutator, and Nereis diversicolor) on microbial communities and biogeochemical processes in sediment cores. C. edule acted as a biodiffuser, mixing surface particles in the top 2 cm of the sediment. Despite this mixing activity, this species had little effect on O2 consumption, water exchange between the water column and the sediment, microbial characteristics, and release of nutrients from the sediment. In contrast, C. volutator and N. diversicolor produced burrows in the sediment that allowed transport of surface particles into biogenic structures. These 2 species doubled the solute exchange between the water column and the sediment. Such modifications of sediment structure and solute transport increased the O2 consumption and the release of nutrients from the sediment. Both C. volutator and N. diversicolor stimulated the microbial communities as indicated by higher percentages of active bacteria. Reduction of the numbers of sulphate reducing bacteria was observed when the 3 invertebrates were present and could be attributed to the penetration of O2 due to animal activities. N. diversicolor had a greater influence than C. volutator on pore water chemistry, ammonium release, and active bacteria. As N. diversicolor burrowed deeper in the sediment than C. volutator, it irrigated a greater volume of sediment. The modes of sediment reworking and structure building, irrigation behaviour, and burrowing depths were factors sufficient to assign the 3 species into different functional groups.

KEY WORDS: Nereis diversicolor · Corophium volutator · Cerastoderma edule · Functional groups · Bioturbation · Microbial activity · Organic matter processing

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