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The abiotic hypothesis posits that the full suite of hydrocarbons found in petroleum can either be generated in the mantle by abiogenic processes, [17] or by biological processing of those abiogenic hydrocarbons, and that the source-hydrocarbons of abiogenic origin can migrate out of the mantle into the crust until they escape to the surface or ...
The prevailing scientific hypothesis is that the transition from non-living to living entities on Earth was not a single event, but a process of increasing complexity involving the formation of a habitable planet, the prebiotic synthesis of organic molecules, molecular self-replication, self-assembly, autocatalysis, and the emergence of cell ...
In ecology, the theory of alternative stable states (sometimes termed alternate stable states or alternative stable equilibria) predicts that ecosystems can exist under multiple "states" (sets of unique biotic and abiotic conditions). These alternative states are non-transitory and therefore considered stable over ecologically-relevant timescales.
The energy incorporated through this process supports life on earth, while the carbon makes up much of the organic matter in living and dead biomass, soil carbon and fossil fuels. It also drives the carbon cycle , which influences global climate via the greenhouse effect .
A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. [1] Many reefs result from natural, abiotic (non-living) processes such as deposition of sand or wave erosion planning down rock outcrops.
The word oxygen in the literature typically refers to molecular oxygen (O 2) since it is the common product or reactant of many biogeochemical redox reactions within the cycle. [37] Processes within the oxygen cycle are considered to be biological or geological and are evaluated as either a source (O 2 production) or sink (O 2 consumption). [36 ...
A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. [55] Many reefs result from natural, abiotic processes but there are also reefs such as the coral reefs of tropical waters formed by biotic processes dominated by corals and coralline algae.
Canton Island typifies the isolated coral atolls dotting the Pacific Ocean. The Structure and Distribution of Coral Reefs, Being the first part of the geology of the voyage of the Beagle, under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836, was published in 1842 as Charles Darwin's first monograph, and set out his theory of the formation of coral reefs and atolls.