Methane-oxidizing bacteria in Pogonophora

Abstract

Abstract Siboglinum poseidoni FLUGEL & LANGHOF, a recently described pogonophore from the central Skagerrak, is equipped with a strand of bacteria-containing tissue. Electron microscopy revealed rod-shaped bacteria with intracytoplasmic membrane stacks hitherto not observed in other endosymbiotic bacteria. Bacteria from the pogonophoran tissue and the sediment were cultured in mineral media designed for chemoautotrophic and methylotropic bacteria. The dominant bacteria in the methane enrichment cultures showed identical membrane stacks. The uptake and oxidation of methane by the animals was proved by incubation experiments with 14CH4. 14C was incorporated by both the homogenized trunk tissue and whole animals within their tubes. The 14CH4-fixation into high molecular cell compounds was demonstrated by autoradiography. Culture experiments with whole animals showed that the pogonophores can be kept longer than two weeks only in the presence of methane (air: methane 4: 1).