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Redox potential (E h) is also closely tied to pH, and both have significant influence on the function of soil-plant-microorganism systems. [1] [8] The main source of electrons in soil is organic matter. [8] Organic matter consumes oxygen as it decomposes, resulting in reducing soil conditions and lower E h. [8]
Soil respiration refers to the production of carbon dioxide when soil organisms respire. This includes respiration of plant roots, the rhizosphere, microbes and fauna.. Soil respiration is a key ecosystem process that releases carbon from the soil in the form of CO 2.
Research concerning the relationship between the thermodynamic quantity entropy and both the origin and evolution of life began around the turn of the 20th century. In 1910 American historian Henry Adams printed and distributed to university libraries and history professors the small volume A Letter to American Teachers of History proposing a theory of history based on the second law of ...
At the same time, the soil is enriched in aluminium and potassium by at least 50%; by titanium, whose abundance triples, and ferric iron, whose abundance increases by an order of magnitude compared with the bedrock. [55] Basaltic rock is more easily weathered than granitic rock due to its formation at higher temperatures and drier conditions.
Soil pH and texture are both factors that can moderate denitrification, with higher pH levels driving the reaction more to completion. [22] Nutrient composition, particularly the ratio of carbon to nitrogen, is a strong contributor to complete denitrification, [ 23 ] with a 2:1 ratio of C:N being able to facilitate full nitrate reduction ...
The important sulfur cycle is a biogeochemical cycle in which the sulfur moves between rocks, waterways and living systems. It is important in geology as it affects many minerals and in life because sulfur is an essential element (), being a constituent of many proteins and cofactors, and sulfur compounds can be used as oxidants or reductants in microbial respiration. [1]
For many substances, the formation reaction may be considered as the sum of a number of simpler reactions, either real or fictitious. The enthalpy of reaction can then be analyzed by applying Hess' law, which states that the sum of the enthalpy changes for a number of individual reaction steps equals the enthalpy change of the overall reaction.
A classical example is the decomposition of mercuric oxide to give oxygen and mercury metal. The reaction was used by Joseph Priestley to prepare samples of gaseous oxygen for the first time. When water is heated to well over 2,000 °C (2,270 K; 3,630 °F), a small percentage of it will decompose into OH, monatomic oxygen, monatomic hydrogen, O ...