MAST200 Lecture 21: Lecture 21
7 Dec 2016
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Document Summary
Support biological communities completely independent of the sun"s energy. Oasis of life in a highly toxic environment. Found in central rift of deep sea spreading zones. Existed for millions of years, but each independent community is highly ephemeral due to the volcanic activity of the vent itself. Cold seawater sinks down through cracks in the crust. Oxygen and potassium are removed from the seawater. Calcium, sulfate, magnesium are removed from fluid. Sodium, calcium, potassium from surrounding crust enter the fluid. Fluids have reached highest temperature; copper, zinc, iron, sulfur from the crust dissolve in the fluid. Hot fluids carrying dissolved metals rise up through crust. Hydrothermal fluids mix with cold, oxygen-rich seawater; metals and sulfur combine to form black metal-sulfide minerals. In white smokers, hydrothermal fluids mix beneath the seafloor before fluid exits chimney. Magma beneath the ocean floor is the engine that drives hydrothermal vents.
