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  2. Oxygen toxicity - Wikipedia

    en.wikipedia.org/wiki/Oxygen_toxicity

    Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen (O 2) at increased partial pressures.Severe cases can result in cell damage and death, with effects most often seen in the central nervous system, lungs, and eyes.

  3. Hypoxia (environmental) - Wikipedia

    en.wikipedia.org/wiki/Hypoxia_(environmental)

    If oxygen depletion becomes extreme, aerobic organisms, like fish, may die, resulting in what is known as a "summer kill". [8] The same phenomena can occur in the winter, but for different reasons. During winter, ice and snow cover can attenuate light, and therefore reduce rates of photosynthesis. The freezing over of a lake also prevents air ...

  4. Oxygen - Wikipedia

    en.wikipedia.org/wiki/Oxygen

    The common allotrope of elemental oxygen on Earth is called dioxygen, O 2, the major part of the Earth's atmospheric oxygen (see Occurrence). O 2 has a bond length of 121 pm and a bond energy of 498 kJ/mol. [42] O 2 is used by complex forms of life, such as animals, in cellular respiration. Other aspects of O

  5. Effects of high altitude on humans - Wikipedia

    en.wikipedia.org/wiki/Effects_of_high_altitude...

    Mitigation may be by supplementary oxygen, pressurisation of the habitat or environmental protection suit, or a combination of both. In all cases the critical effect is the raising of oxygen partial pressure in the breathing gas. [1] Room air at altitude can be enriched with oxygen without introducing an unacceptable fire hazard.

  6. Anaerobic organism - Wikipedia

    en.wikipedia.org/wiki/Anaerobic_organism

    Facultative anaerobes can grow with or without oxygen because they can metabolize energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more adenosine triphosphate (ATP) than either fermentation or anaerobic respiration. Microaerophiles need oxygen because they cannot ferment or respire ...

  7. Great Oxidation Event - Wikipedia

    en.wikipedia.org/wiki/Great_Oxidation_Event

    The appearance of highly reactive free oxygen, which can oxidize organic compounds (especially genetic materials) and thus is toxic to the then-mostly anaerobic biosphere, may have caused the extinction/extirpation of many early organisms on Earth – mostly archaeal colonies that used retinal to use green-spectrum light energy and power a form ...

  8. Breathing gas - Wikipedia

    en.wikipedia.org/wiki/Breathing_gas

    A breathing gas is a mixture of gaseous chemical elements and compounds used for respiration. Air is the most common and only natural breathing gas. Other mixtures of gases, or pure oxygen, are also used in breathing equipment and enclosed habitats such as scuba equipment, surface supplied diving equipment, recompression chambers, high-altitude mountaineering, high-flying aircraft, submarines ...

  9. Aerobic organism - Wikipedia

    en.wikipedia.org/wiki/Aerobic_organism

    3: Facultative anaerobes can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration. 4: Microaerophiles need oxygen because they cannot ferment or respire anaerobically. However ...