title: Variation in physiological indicators in Bathymodiolus azoricus (Bivalvia: Mytilidae) at the Menez Gwen Mid-Atlantic Ridge deep-sea hydrothermal vent site within a year.
abstract: Bathymodiolus azoricus, thriving at Mid-Atlantic Ridge deep vents, benefits from a symbiosis with methane- and sulphide-oxidising (MOX and SOX) bacteria, and feeds on particulate and dissolved organic matter. To investigate the temporal evolution in their nutrition adult mussels were collected from one location at the Menez Gwen vent site (817 m depth) on four occasions between 2006 and 2007 and studied using different techniques, including stable isotope analyses and FISH. Gill and mantle tissues delta13C and delta15N signatures varied by 2-3 per thousand during the year and these variations were linked to fluctuations in tissue condition index, C and N contents and SOX/MOX volume ratios as quantified by 3D-FISH. October and January mussels presented a particularly poor condition, possibly related with the prolonged summer period of low sea-surface primary production and/or with the stress of the transplant to acoustically retrievable cages for the October mussels, and with their reproductive state in January mussels, since they were spawning. Our results point to the possibility that May mussels benefited from a pulse of sinking sea-surface plankton material. Results underline the dependency of stable isotopic signatures on the physiological state of the mussel at the time of collection, and on the type of tissue analyzed.
authors.affiliation: Department of Analytical and Environmental Chemistry & Earth System Sciences, Vrije Universiteit Brussel, Brussels, Belgium. virginie_riou@hotmail.com
authors.forename: Virginie
authors.initials: V
authors.lastname: Riou
authors.forename: Sébastien
authors.initials: S
authors.lastname: Duperron
authors.forename: Sébastien
authors.initials: S
authors.lastname: Halary
authors.forename: Frank
authors.initials: F
authors.lastname: Dehairs
authors.forename: Steven
authors.initials: S
authors.lastname: Bouillon
authors.forename: Inès
authors.initials: I
authors.lastname: Martins
authors.forename: Ana
authors.initials: A
authors.lastname: Colaço
authors.forename: Ricardo
authors.initials: R
authors.lastname: Serrão Santos
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D002250:Carbon Radioisotopes / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D005880:Gills / Q000737:chemistry; D017404:In Situ Hybridization, Fluorescence; D009590:Nitrogen Radioisotopes / Q000032:analysis; D009792:Oceans and Seas; D013997:Time Factors
chemical_list: D002250:Carbon Radioisotopes; D009590:Nitrogen Radioisotopes