Hydrothermal Vent Chemistry
Black smokers · metal sulfides · chemosynthesis · extreme geochemistry
Physics: Black smokers form where seawater percolates to ~2 km depth, heats to 350–400°C at the ridge axis, and rises buoyantly. At depth, supercritical water leaches metals (Fe, Zn, Cu, Mn) from basalt. On mixing with cold seawater (2°C, pH 8), metal sulfides precipitate instantly: Fe²⁺ + S²⁻ → FeS(s); Cu⁺ + HS⁻ → CuS + H⁺. Chemolithotrophs (Thiomicrospira, Aquificales) oxidize H₂S: H₂S + ½O₂ → S + H₂O + energy. These support tube worms, clams, shrimp — primary productivity without sunlight.