Atmosphere - Groundwater - Lithosphere

Considerable amounts of carbon dioxide are produced in the soil as a result of microbial degradation reactions. Particularly during the summer, concentrations of C02 soil gas of approximately 1-5 Vol% can be reached under humic climate. This amount is a significant increase compared to C02 partial pressures in the atmosphere of 0.03 Vol% (see also the exercise in chapter 3.1.1.6). Simulate the effect that a soil C02 partial pressure of 1 Vol% has on the following rainwater Na = 8, K = 7, Ca = 90, Mg = 29, S042 = 82, N03 = 80, C(+4) = 13 and Cl = 23 [all units in pmol/L], Value of pH 5.1, temperature 21°C. 

Attention In PHREEQC, C(+4) has indeed to be expressed as C(+4) and not as alkalinity as we did it so far. Because of the low concentrations in rainwater, a conventional determination of the alkalinity is not possible, only the determination of the TIC (total inorganic carbon, C(+4)) can be done. 

---

Atmosphere — Groundwater - Lithosphere 4.1.2.1 Precipitation under the influence of soil C02... 

There are 5 major reservoirs in the Earth system atmosphere, biosphere (vegetation, animals), soils, hydrosphere (oceans, lakes, rivers, groundwater), and the lithosphere (Earth crust). Elemental cycles of carbon, oxygen, nitrogen, sulfur, phosphorus, and other elements interact with the different reservoirs of the Earth system. The carbon cycle has important aspects in tropical forests due to the large amount of carbon stored in the tropical forests and the high rate of tropical deforestation 0acob 1999)-... 

---