Hydrocarbons in the fluids spewing from a set of hydrothermal vents on the seafloor of the central Atlantic were produced by inorganic chemical reactions within the ocean crust, scientists suggest. The finding holds possibly profound implications for the origins of life.

Most hydrothermal vents spew a highly acidic, mineral-rich broth at temperatures as high as 400°C. The sulfide minerals that precipitate when those hot fluids mix with near-freezing seawater form dark, crumbly chimneys that typically reach heights of only 20 meters or so before they collapse. At the Lost City site, however, vent fluids are alkaline, have temperatures between 28°C and 90°C, and are rich in dissolved carbonates, Proskurowski notes. Because carbonate minerals are much stronger than sulfides, the lofty white chimneys that form in the Lost City can grow at least 60 m tall.