The hydrologic cycle describes the essential movement of water in the ecosphere, necessary for life. It is one of the fundamental metabolic measures of the ecosystem. The total mass of water is nominally constant over the sum of various reservoirs of ice, fresh water, subterranean, brine and atmospheric vapor. Water moves naturally from one reservoir to another through physical processes of evaporation, condensation, precipitation, infiltration, surface runoff, and subsurface flow. Water can also be mechanically pumped in a CELSS, and is involved chemically in the photosynthesis and transpiration of plants.
In transport, the water often goes through different phases: liquid, solid (ice) and vapor (steam/humidity), thermodynamically involving an energy exchange, and hence temperature changes: Evaporation, sublimation, and melting take up energy from the surroundings and cool the environment; condensation and fusion(freezing) release energy and warm the environment. External (e.g., solar) energy can also be used to drive these phenomenon inside the habitat, while maintaining a closed system.
The flow of liquid water transports minerals toward the sinks of the habitat. The evaporative phase of the cycle purifies water which then replenishes the land with freshwater, but at the same time creates a brine in the sink (like the oceans on Earth).
In transport, the water often goes through different phases: liquid, solid (ice) and vapor (steam/humidity), thermodynamically involving an energy exchange, and hence temperature changes: Evaporation, sublimation, and melting take up energy from the surroundings and cool the environment; condensation and fusion(freezing) release energy and warm the environment. External (e.g., solar) energy can also be used to drive these phenomenon inside the habitat, while maintaining a closed system.
The flow of liquid water transports minerals toward the sinks of the habitat. The evaporative phase of the cycle purifies water which then replenishes the land with freshwater, but at the same time creates a brine in the sink (like the oceans on Earth).