River water cycle

Sabater S (2008) Alterations of the global water cycle and their effects on river structure, function and services. Ereshw Rev 1 75-88... 

The Water Cycle. The evaporation of water from land and water surfaces, the transpiration from plants, and the condensation and subsequent precipitation of rain cause a cycle of transportation and redistribution of water, a continuous circulation process known as the hydrologic cycle or water cycle (see Fig. 86). The sun evaporates fresh water from the seas and oceans, leaving impurities and dissolved solids behind when the water vapor cools down, it condenses to form clouds of small droplets that are carried across the surface of the earth as the clouds are moved inland by the wind and are further cooled, larger droplets are formed, and eventually the droplets fall as rain or snow. Some of the rainwater runs into natural underground water reservoirs, but most flows, in streams and rivers, back to the seas and oceans, evaporating as it travels. 

ABSTRACT The locations, magnitudes, variations and mechanisms responsible for the atmospheric C02 sink are uncertain and under debate. Previous studies concentrated mainly on oceans, and soil and terrestrial vegetation as sinks. Here, we show that there is an important C02 sink in carbonate dissolution, the global water cycle and photosynthetic uptake of DIC by aquatic ecosystems. The sink constitutes up to 0.82 Pg C/a 0.24 Pg C/a is delivered to oceans via rivers and 0.22 Pg C/a by meteoric precipitation, 0.12 Pg C/a is returned to the atmosphere, and 0.23 Pg C/a is stored in the continental aquatic ecosystem. The net sink could be as much as 0.70 Pg C/a, may increase with intensification of the global water cycle, increase in C02 and carbonate dust in atmosphere, reforestation/afforestation, and with fertilization of aquatic ecosystems. Under the projection of global warming for the year 2100, it is estimated that this C02 sink may increase by 22%, or about 0.18 Pg c/a. 

Figure 8. (A) Shell 8180 and 813C cycle from one sample from the Siwaliks of Nepal. Note that the calculated amplitude of SlsO change in the river water is 10%o if cool temperature is associated with the most positive shell 8180 value. The amplitude is larger (13.65%o) if the temperature association is reversed. Modified from Dettman et al. 2001. (B) Tooth enamel SlsO cycle from the Siwaliks of Pakistan, showing similar amplitude variations for older vs. younger teeth.

Evaporation is the process of changing a liquid into a gas and is an essential part of the planets water cycle. Evaporation moves Earths liquid water from the surface of the oceans, lakes, rivers, and streams into the atmosphere, where it resides temporarily as a gas. 

The study of energy and water cycles carried out within the GEWEX program with regard to the carbon cycle was an important step forward. For example, analysis of data for the Mississippi River basin into the closedness of cycles has shown that cycles can be balanced within the error + 15%. Meteorological studies into the causes of precipitation in warm seasons in the southwest of the U.S.A. have shown that monsoons play a substantial role. 

Avery G.B. Kieber R.J. Willey J.D. Shank G.C. and Whitehead R.F. (2004). Impact of hurricanes on the flux of rainwater and Cape Fear River water dissolved organic carbon to Long Bay, southeastern United States. Global Biogeochemical Cycles, 18(GB3085), doi 10.1029/2004GB002229. 

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