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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]
Marine biogeochemical cycles are biogeochemical cycles that occur within marine environments, that is, in the saltwater of seas or oceans or the brackish water of coastal estuaries. These biogeochemical cycles are the pathways chemical substances and elements move through within the marine environment. In addition, substances and elements can ...
This process results in the continual recycling of nitrogen gas involving the ocean. Chemical cycling describes systems of repeated circulation of chemicals between other compounds, states and materials, and back to their original state, that occurs in space, and on many objects in space including the Earth. Active chemical cycling is known to ...
The iron–sulfur world hypothesis is a set of proposals for the origin of life and the early evolution of life advanced in a series of articles between 1988 and 1992 by Günter Wächtershäuser, a Munich patent lawyer with a degree in chemistry, who had been encouraged and supported by philosopher Karl R. Popper to publish his ideas.
Alternative abiogenesis scenarios. A scenario is a set of related concepts pertinent to the origin of life (abiogenesis), such as the iron-sulfur world. Many alternative abiogenesis scenarios have been proposed by scientists in a variety of fields from the 1950s onwards in an attempt to explain how the complex mechanisms of life could have come ...
Sulfur metabolism. Sulfur is metabolized by all organisms, from bacteria and archaea to plants and animals. Sulfur can have an oxidation state from -2 to +6 and is reduced or oxidized by a diverse range of organisms. [1] The element is present in proteins, sulfate esters of polysaccharides, steroids, phenols, and sulfur-containing coenzymes.
Sulfur assimilation is the process by which living organisms incorporate sulfur into their biological molecules. [1] In plants, sulfate is absorbed by the roots and then transported to the chloroplasts by the transipration stream where the sulfur are reduced to sulfide with the help of a series of enzymatic reactions.
Reduced sulfur compounds such as H 2 S produced by the hydrothermal vents are a major source of energy for sulfur metabolism in microbes. [11] Oxidation of reduced sulfur compounds into forms such as sulfite , thiosulfate , and elemental sulfur is used to produce energy for microbe metabolism such as synthesis of organic compounds from ...