Outcropping Methane Gas Hydrates and Methane Seeps
Energy Source

    Methane and hydrogen sulfide are present in abundance directly below the mussel beds (Paull et al., 1996).  The clams appear to have a symbiotic relationship with both methanogenic and sulfate reducing bacteria.  This idea is supported by a carbon isotopic composition  of δ13C  -55.77% in the gills of ten sampled clams (Van Dover et al. 2003).  This composition shows that the carbon was derived from biogenic methane production, rather than carbon used in photosynthesis.

Overview picture showing juvenile clams growing amid older, dead clam beds where samples for δ13C analysis were taken.  Scale bar = 10 cm.  (Van Dover 2003 et al. 2003).




    Fisher et al. 2000 documented a community of polychaetes living directly on hydrate outcropping in the Gulf of Mexico.  The polychaetes were grazing on the hydrate bacteria and supplying oxygen to their habitats, which appears to contribute to the dissolution of hydrates in surface sediments.

A new species of polychaetes, dubbed ice worms, thriving on bacteria living on the gas hydrate.  (picture curtesy of http://bioc.rice.edu/precollege/galbay/galbay99/students/Iceworms/Iceworms.htm).

Gas Hydrate: Introduction

Gas Hydrate: Community Structure

Gas Hydrate: Sustainability

Gas Hydrate: Signal in Sediments

Gas Hydrate: Locations

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