Methane-based symbiosis in a mussel, Bathymodiolus platifrons, from cold seeps in Sagami Bay, Japan |
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Authors: | James P Barry Kurt R Buck Randall K Kochevar Douglas C Nelson Yoshihiro Fujiwara Shana K Goffredi Jun Hashimoto |
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Institution: | Monterey Bay Aquarium Research Institute, Moss Landing, California 95039, USA;University of California, Division of Biological Sciences, Davis, California 95616, USA;Japan Marine Science and Technology Center, Yokosuka 237, Japan |
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Abstract: | Abstract. Bathymodiolus platifrons , a chemosynthetic mussel from cold seeps off Japan, relies for its nutrition on the productivity of methylotrophic or methanotrophic endosymbionts. High densities of bacterial symbionts appearing to be type I methanotrophs were observed in transmission electron micrographs of gill tissues. Methanol dehydrogenase activity in gill tissue from a single individual was positive compared to non-methanotrophic control samples, indicating a high potential for methanotrophy. Stable isotopic ratios of carbon in symbiont-containing gill tissue, as well as host tissues, were extremely depleted in 13C, and similar to values reported for other methanotrophic species. TEMs of gill tissue showing symbionts in various stages of digestion support the hypothesis that carbon transfer from symbionts to B. platifrons occurs through intracellular digestion of the symbionts. Discovery of methane- or methanolbased symbioses in B. platifrons from cold seeps in Sagami Bay extends the range of such symbioses to include cold seeps and hydrothermal vents, and supports the idea that environmental methane levels control the distribution of these symbioses. |
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Keywords: | chemosynthesis methanotrophy methylotrophy bivalve biogeography |
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