|Bioaccumulation of metals and detoxification processes within hydrothermal vent molluscs: the case of the bivalve Bathymodiolus sp. form the Mid-Atlantic Ridge|
Rousse, N.; Boulegue, J.; Geret, F.; Fiala-Médioni, A. (1997). Bioaccumulation of metals and detoxification processes within hydrothermal vent molluscs: the case of the bivalve Bathymodiolus sp. form the Mid-Atlantic Ridge, 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. 137-138
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 |
- Rousse, N.
- Boulegue, J.
- Geret, F.
- Fiala-Médioni, A.
The hydrothermal environment is characterized by high metal concentrations, as well as high hydrogen sulphide content, related to interactions of the convective seawater circulation with basaltic rocks inside the ocean crust. The biological communities associated with a hydrothermal system can survive in this toxic environment owing to their ability to regulate intracellular metal levels by excretion or accumulation of metal ions in non-toxic forms. The main detoxication processes known in bivalve molluscs are trapping and precipitation of metals in lysosomal systems, or binding to specific and soluble ligands, such as metallothioneins. These last molecules are heat stable and characterized by a high cystein content. Tissues of the mussel Bathymodiolus sp. collected at two sites, Menez-Gwen (37 degree 50'30"N; 800 m depth) and Lucky-Strike (37 degree 17'30"N; 1700m depth), show important concentrations of essential metals such as iron, zinc, copper and manganese, as well as toxic metals such as cadmium, silver, strontium and barium. All these metals can enter as dissolved ions into the gills or as particles phagocyted by the digestive gland. Lower levels were always found within the mantle as compared to gills and digestive gland. Large metallothionein concentrations were detected in all individuals. The synthesis of these proteins can be induced by exposition to high levels of Zn, Cu, Cd and Hg, these metals being able to bind to metallothioneins. The study of Zn, Cu and Cd distribution shows that these metals are more often located within insoluble fractions, hence most probably in lysosomal systems, which can be one of the dominant mechanism of detoxication. Only some organisms from Menez-Gwen used metallothioneins to detoxify zinc within gills tissues. The metallothioneins we have investigated seem to have a low metal (Zn+Cu+Cd) content, implying that they could rather play a role in sulphur transport than in metals' detoxication.The hydrothermal activity is an important source of metals for the world ocean and the deep biologic pump play non-negligible role in cycles of oceanic metals. This could be quantified only when more data on bioaccumulation and detoxication processes are obtained.