Marine Ecology Progress Series
MEPS is a leading hybrid research journal on all aspects of marine, coastal and estuarine ecology. Priority is given to outstanding research that advances our ecological understanding.
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DOI: https://doi.org/10.3354/meps08515
copiedMixotrophy in the deep sea: a dual endosymbiotic hydrothermal mytilid assimilates dissolved and particulate organic matter
- Virginie Riou
- Ana Colaço
- Steven Bouillon
- Alexis Khripounoff
- Paul Dando
- Perrine Mangion
- Emilie Chevalier
- Michael Korntheuer
- Ricardo Serrão Santos
- Frank Dehairs
ABSTRACT: Bathymodiolus azoricus mussels thrive 840 to 2300 m deep at hydrothermal vents of the Azores Triple Junction on the Mid-Atlantic Ridge. Although previous studies have suggested a mixotrophic regime for this species, no analysis has yet yielded direct evidence for the assimilation of particulate material. In the present study, tracer experiments in aquaria with 13C- and 15N-labelled amino acids and marine cyanobacteria demonstrate for the first time the incorporation of dissolved and particulate organic matter in soft tissues of vent mussel. The observation of phytoplanktonic tests in wild mussel stomachs highlights the occurrence of in situ ingestion of sea-surface-derived material. Particulate organic carbon fluxes in sediment traps moored away from direct vent influence are in agreement with carbon export estimates from the surface ocean above the vents attenuated by microbial degradation. Stable isotope composition of trapped organic matter is similar to values published in the literature, but is enriched by +7‰ in 13C and +13‰ in 15N, relative to mussel gill tissue from the Menez Gwen vent. Although this observation suggests a negligible contribution of photosynthetically produced organic matter to the diet of B. azoricus, the tracer experiments demonstrate that active suspension-feeding on particles and dissolved organic matter could contribute to the C and N budget of the mussel and should not be neglected.
KEYWORDS
Virginie Riou (Co-author)
- IMAR-University of the Azores, Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
- Earth System Sciences Group, Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
Ana Colaço (Co-author)
- IMAR-University of the Azores, Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
Steven Bouillon (Co-author)
- Earth System Sciences Group, Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
- Katholieke Universiteit Leuven, Department of Earth and Environmental Sciences, 3001 Heverlee, Belgium
Alexis Khripounoff (Co-author)
- Ifremer, Centre de Brest, DEEP/LEP, 29280 Plouzané, France
Paul Dando (Co-author)
- Marine Biological Association of the UK, Plymouth PL1 2PB, UK
Perrine Mangion (Co-author)
- Earth System Sciences Group, Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
Emilie Chevalier (Co-author)
- Earth System Sciences Group, Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
Michael Korntheuer (Co-author)
- Earth System Sciences Group, Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium
Ricardo Serrão Santos (Co-author)
- IMAR-University of the Azores, Department of Oceanography and Fisheries, 9901-862 Horta, Portugal
Frank Dehairs (Co-author)
- Earth System Sciences Group, Department of Analytical and Environmental Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium