SYRACUSE, N.Y. - An expansive ecosystem of knee-high mud volcanoes, snowy microbial mats and flourishing clam communities lies beneath the collapsed Larsen Ice Shelf in Antarctica, say researchers. The discovery made in February in a deep glacial trough in the northwestern Weddell Sea was detailed this week in Eos, the weekly newspaper of the American Geophysical Union. Such sunless, cold-vent ecosystems have been found elsewhere — near Monterey, Calif., in the Gulf of Mexico and in the Sea of Japan — but never in Antarctica, the report said. "Seeing those organisms on the ocean bottom, it's like lifting the carpet...