Evapotranspiration mechanisms

ET is the evaporation of water from the soil surface and by plant transpiration (primarily through the stomata on the plant s leaves). ET should be carefully considered during all stages of design since it will be the largest mechanism of water removal in the water balance for an ET cover. With current knowledge, it is necessary to estimate potential evapotranspiration (PET) first and then using the PET estimate the actual evapotranspiration (AET) for the site. 

High atmospheric COj leads to fester evapotranspiration rates, providing another mechanism by which water vapor levels increase. This is singularly important as water vapor changes are now recognized by the IPCC as the largest feedback affecting climate sensitivity. 

Only part of the water infiltrating into the ground keeps moving downward into the saturated groundwater zone. An important part of infiltrated water is transferred back into the atmosphere. Two major mechanisms are involved evaporation and transpiration, together called evapotranspiration. 

A similar modern accumulation of silicon, as opal mineral, was monitored in Boreal Peat ecosystems in Belarussia and in floodplains of varions rivers in the Central Russian Plain. The biogeochemical mechanism of this silicon species formation is connected with the evapotranspiration of ground waters enriched in silicon by plants and deposition of amorphous silicon (Kovda, 1984). 

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