Subterranean Fishes of the World

3447

2011

Ecology

2056-2062

92

Photoautotrophs are generally considered to be the base of food webs, and habitats that lack light, such as caves, frequently rely on surface-derived carbon. Here we show, based on analysis of gut contents and stable isotope ratios of tissues (13C:12C and 15N:14N), that sulfur-oxidizing bacteria are directly consumed and assimilated by the fish Poecilia mexicana in a sulfide-rich cave stream in Tabasco state, Mexico. Our results provide evidence of a vertebrate deriving most of its organic carbon and nitrogen from in situ chemoautotrophic production, and reveals the importance of alternative energy production sources supporting animals in extreme environments. KW: Cave fish, chemoautotroph, food web, hydrogen sulfide, Poecilia mexicana, production source.

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