The term anoxia means a total depletion in the level of
oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
, an extreme form of hypoxia or "low oxygen". The terms anoxia and hypoxia are used in various contexts:
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Anoxic waters, sea water, fresh water or groundwater that are depleted of dissolved oxygen
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Anoxic event, when the Earth's oceans become completely depleted of oxygen below the surface levels
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Euxinic
Euxinia or euxinic conditions occur when water is both anoxic and sulfidic. This means that there is no oxygen (O2) and a raised level of free hydrogen sulfide (H2S). Euxinic bodies of water are frequently strongly stratified, have an oxic, highly ...
, anoxic conditions in the presence of hydrogen sulfide
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Hypoxia (environmental)
Hypoxia refers to low oxygen conditions. Normally, 20.9% of the gas in the atmosphere is oxygen. The partial pressure of oxygen in the atmosphere is 20.9% of the total barometric pressure. In water, oxygen levels are much lower, approximately 7 p ...
, low oxygen conditions
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Hypoxia (medical)
Hypoxia is a condition in which the body or a region of the body is deprived of adequate oxygen supply at the tissue level. Hypoxia may be classified as either '' generalized'', affecting the whole body, or ''local'', affecting a region of the bo ...
, when the body or a region of the body is deprived of adequate oxygen supply
** Cerebral anoxia, when the brain is completely deprived of oxygen, an extreme form of
cerebral hypoxia
Cerebral hypoxia is a form of hypoxia (reduced supply of oxygen), specifically involving the brain; when the brain is completely deprived of oxygen, it is called ''cerebral anoxia''. There are four categories of cerebral hypoxia; they are, in o ...
See also
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''Anoxia'' (beetle), a genus of
scarab beetle
The family Scarabaeidae, as currently defined, consists of over 30,000 species of beetles worldwide; they are often called scarabs or scarab beetles. The classification of this family has undergone significant change in recent years. Several sub ...
s
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Oxygen saturation, a relative measure of the oxygen dissolved or carried in a medium; a measure of the severity of hypoxic conditions
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Oxygen toxicity
Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen () at increased partial pressures. Severe cases can result in cell damage and death, with effects most often seen in the central nervous system, lu ...
(hyperoxia), the opposite condition of hypoxia, an excess of oxygen in body tissues
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Oxygen-free (disambiguation) Oxygen-free may refer to the absence of oxygen in an environment or in a material.
Not to be confused with ''free oxygen'', oxygen in the atmosphere of Earth that is not combined with other elements and may be breathed by living beings.
Environm ...
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