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At least half of the oxygen produced on Earth comes from the ocean, mostly from tiny photosynthesizing plankton. But marine life also uses roughly the same amount of oxygen to breathe, for cellular respiration, and in the decomposition process.
Common uses of oxygen include production of steel, plastics and textiles, brazing, welding and cutting of steels and other metals, rocket propellant, oxygen therapy, and life support systems in aircraft, submarines, spaceflight and diving.
Oxygen cycle refers to the movement of oxygen through the atmosphere (air), biosphere (plants and animals) and the lithosphere (the Earth’s crust). The oxygen cycle demonstrates how free oxygen is made available in each of these regions, as well as how it is used.
At some point early in the game, perhaps within hundreds of millions of years of Earth's formation, a mechanism for pulling energy provided by sunlight from certain chemicals was chanced upon. Though it was technically photosynthesis, it wasn't the kind that left an excess of oxygen.
Oxygen is a colourless, odourless, tasteless gas essential to living organisms, being taken up by animals, which convert it to carbon dioxide; plants, in turn, utilize carbon dioxide as a source of carbon and return the oxygen to the atmosphere.
Around 350 million years ago, Earth’s oxygen levels hit 20%, which is roughly the percentage they are at today. Oxygen concentrations continued to rise to 35%, before a cooling climate and the large-scale death of many plants sent concentrations plummeting to 12%.
The Origin of Oxygen in Earth's Atmosphere. The breathable air we enjoy today originated from tiny organisms, although the details remain lost in geologic time. David Biello is a contributing ...
On modern Earth, the dominant tectonic activity is called plate tectonics, where oceanic crust — the outermost layer of the Earth under the oceans — sinks into the Earth’s mantle (the area...
Oxygen is produced by photosynthesizing organisms that live in the ocean, in fresh water, and on land. These organisms include bacteria, algae and plants. Photosynthesizing algae in the ocean produce around 70% of oxygen in the atmosphere.
Far more controversial is the timing of the first emergence of O 2 -producing photosynthesis, the source of essentially all oxygen in the atmosphere. Among the key questions is whether this...