Hydrogen cycle

Article

The hydrogen cycle describes the movement and chemical transformation of hydrogen among water, living organisms, the atmosphere, rocks, and Earth's interior. Most hydrogen near the surface is contained in water and organic compounds.

Water moves through evaporation, condensation, precipitation, runoff, infiltration, freezing, melting, and biological uptake. In living systems, hydrogen is transferred through photosynthesis, respiration, fermentation, and many metabolic reactions.

Hydrogen also participates in geochemical processes such as mineral hydration, weathering, hydrothermal reactions, volcanic degassing, and exchanges between the crust and mantle. Small amounts occur in atmospheric gases such as methane and molecular hydrogen.

The hydrogen cycle is closely connected with the water, carbon, oxygen, and energy cycles. Human production and use of hydrogen fuel can alter local flows, but the natural cycle is dominated by water and biological and geological transformations.

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• Source / publisher: Wikipedia
• URL type: WWW
• Credits: Wikipedia
• URL: https://en.wikipedia.org/wiki/Hydrogen_cycle