Ultrastructural and molecular evidence for potentially symbiotic bacteria within the byssal plaques of the deep-sea hydrothermal vent mussel Bathymodiolus azoricus.

This study reports on the presence of a putatively symbiotic bacterial flora within the byssus plaque of the deep sea hydrothermal mussel Bathymodiolus azoricus, contributing to metal sequestration/deposition and testing positive to methane oxidizing symbiont-specific fluorescent probes. Combining an array of approaches including histology, electron microscopy, X-ray microanalysis, analytical chemistry, and microbiology we provide evidence for the frequently assumed, but rarely shown influence of prokaryotes on the biogeochemical cycling of metals as well as inorganic C sources (i.e.

Distribution of micro-essential (Fe, Cu, Zn) and toxic (Hg) metals in tissues of two nutritionally distinct hydrothermal shrimps.

Hydrothermal ecosystems of the Mid Atlantic Ridge (MAR) are dominated by shrimps and mussels that are naturally exposed to elevated levels of heavy metals providing unique in situ laboratories for ecotoxicological investigations. This study reports on the tissue compartmentalization of both micro-essential (Fe, Zn, Cu) and toxic metals (Hg) in two nutritionally distinct cariddean vent shrimps: Rimicaris exoculata and Mirocaris fortunata, in order to shed light on organism-biota interactions at hydrothermal vents. High metal concentrations in shrimps confirmed extreme exposure levels at both geochemically different hydrothermal vents (Rainbow and Lucky Strike).

Behavioural response to the bioavailability of inorganic mercury in the hydrothermal mussel Bathymodiolus azoricus.

The hydrothermal vent bivalve Bathymodiolus azoricus is naturally exposed to putatively elevated levels of mercury (Hg), exposure that dates back to the geological occurrence of vent ecosystems, and thus may have evolved evolutionary detoxification mechanisms. Therefore, it was used as a model organism in the present investigation to study the Hg-animal interaction. Mussels were exposed to inorganic Hg by daily administration of 20 microg l(-1) Hg for 21 days (cumulative added concentration was 420 microg l(-1), i.