|Description of the environment of hydrothermal mussel beds at Lucky Strike and Menez Gwen Fields, MAR|
Caprais, J.-C.; Sarradin, P.-M.; Comtet, T.; Aminot, A. (1997). Description of the environment of hydrothermal mussel beds at Lucky Strike and Menez Gwen Fields, MAR, in: Biologie des sources hydrothermales profondes = Biology of deep-sea hydrothermal vents: Journées d'échanges du Programme DORSALES = DORSALES Workshop Roscoff 6-8 octobre 1997. Cahiers de Biologie Marine, 38(2): pp. 115
In: (1997). Biologie des sources hydrothermales profondes = Biology of deep-sea hydrothermal vents: Journées d'échanges du Programme DORSALES = DORSALES Workshop Roscoff 6-8 octobre 1997. Cahiers de Biologie Marine, 38(2)[s.n.][s.l.]. 111-149 pp., more
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723, more
|Authors|| || Top |
- Caprais, J.-C.
- Sarradin, P.-M.
- Comtet, T.
- Aminot, A.
A large number of water samples were collected around the communities of hydrothermal mussels (Bathymodiolus like) in the Lucky Strike (37 degree 17 N, 1700 m depth) and Menez Gwen (37 degree 50 N, 850 in depth) areas, Mid Atlantic Ridge, and analysed for chemical constituents. The environment surrounding the organisms is a dilute hydrothermal medium (88 to 100% of seawater) with a pH between 6.2 and 8 and hydrogen sulphide concentrations ranging from 0 to 62 micromol super(-1). Ambient dissolved organic carbon (DOC) concentrations are high compared to the seawater value, suggesting that the ecosystem is highly productive. The medium is not only a simple mixing of seawater and hydrothermal fluid but is also modified by the biological activity. Production of ammonium and DOC, consumption of nitrate and sulphide were observed in the vicinity of the organisms. This modification can be related to the distribution of the organisms and their need for different chemical species, not only supplied by the hydrothermal fluid but produced or excreted by the communities. An empirical distinction between the extreme classes of the mussel sizes (> 6 cm and < 3 cm) based on an estimation of the mussels length on the videos revealed that the size distribution of the communities is related to the presence of different environments. This spatial segregation of sizes is also observed in-situ and when studying length frequency distribution: the large size classes are present in a richer environment, closer to the vent emissions, than the small size classes. This could indicate differences in the growth rate in relation with the availability of the energy sources, real energy needs of the communities, competition for energy and space, and/or different settlement periods.