KeywordsBiological Activity Chemical Process Natural Environment Bioorganic Chemistry Surface Oxidant
Abiotic refers to the physical and chemical processes that take place in natural environments but are driven by mechanisms that do not involve any biological activity. Although major physical and chemical cycles on Earth can hardly escape the activity of the biosphere, some processes do not depend on biological activities. For example, this is the case of the formation of hydrothermal deposits that are based on redox, volatile fugacity, and high thermal conditions. Some abiotic processes are involved in the production of surface oxidants through photochemical reactions in planet atmospheres as has been proposed to explain the presence of perchlorates on Mars. Paradoxically, different abiotic pathways (thermal, radiolytic, or photochemical) create the chemical disequilibrium which is strictly necessary to fuel physical and chemical cycles on planets depleted of life. Some abiotic pathways have likely been essential to originate the primary biochemical machinery that drove the emergence of life on Earth. In this sense, most abiotic processes support the production of the compounds and chemical disequilibrium essential for a region of the universe to become habitable.