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In contrast, anthropogenic sources are caused by human activity. Some sources of a trace gas are biogenic processes, outgassing from solid Earth, ocean emissions, industrial emissions, and in situ formation. [1] A few examples of biogenic sources include photosynthesis, animal excrements, termites, rice paddies, and wetlands. Volcanoes are the ...
Greenhouse gas emissions from bioenergy can be low because when vegetation is harvested for bioenergy, new vegetation can grow that will absorb CO 2 from the air through photosynthesis. [2] After the biomass is harvested, energy ("bioenergy") is extracted in useful forms (electricity, heat, biofuels , etc.) as the biomass is utilized through ...
[9]: 2248 Subsequently, a pool is defined as "a reservoir in the Earth system where elements, such as carbon and nitrogen, reside in various chemical forms for a period of time". [ 9 ] : 2244 The United States Geological Survey (USGS) defines carbon sequestration as follows: "Carbon sequestration is the process of capturing and storing ...
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens.It is the fourth and final stage of anaerobic digestion.
Carbon is a primary component of all known life on Earth, and represents approximately 45–50% of all dry biomass. [1] Carbon compounds occur naturally in great abundance on Earth. Complex biological molecules consist of carbon atoms bonded with other elements , especially oxygen and hydrogen and frequently also nitrogen , phosphorus , and ...
A biogenic substance is a product made by or of life forms. While the term originally was specific to metabolite compounds that had toxic effects on other organisms, [1] it has developed to encompass any constituents, secretions, and metabolites of plants or animals. [2] In context of molecular biology, biogenic substances are referred to as ...
Section 202(a)(1) of the Clean Air Act requires the Administrator of the EPA to establish standards "applicable to the emission of any air pollutant from…new motor vehicles or new motor vehicle engines, which in [her] judgment cause, or contribute to, air pollution which may reasonably be anticipated to endanger public health or welfare" (emphasis added). [3]
Bubbles of methane, created by methanogens, that are present in the marsh, more commonly known as marsh gas. Marsh gas, also known as swamp gas or bog gas, is a mixture primarily of methane and smaller amounts of hydrogen sulfide, carbon dioxide, and trace phosphine that is produced naturally within some geographical marshes, swamps, and bogs.