Oxygen cycle

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The oxygen cycle is the biogeochemical cycle of oxygen in four main dams: the atmosphere (air), the total content of biological matter in the biosphere (the global sum of all ecosystems), the hydrosphere (the combined mass of water found at, , and above the surface of the planet Earth), and the lithosphere/crust of the Earth. The main driving factor of the oxygen cycle is photosynthesis, which is responsible for Earth's modern atmosphere and Earth's life (see Great Oxygen Events).

Video Oxygen cycle

Reservoir

So far, the largest reservoir of Earth's oxygen is in silicate minerals and oxides of crust and mantle (99.5 wt%). The Earth's atmosphere, the hydrosphere and the biosphere together weigh less than 0.05% of the total mass of the Earth. Oxygen is one of the most abundant elements on Earth and represents most of each of the main dams:

• The atmosphere is 21% oxygen based on the available volume mainly as free oxygen molecules (O ₂ ) with other oxygen-containing molecules including ozone (O ₃ ) (H ₂ O), and sulfur and nitrogen oxides (SO ₂ , NO, N < sub> 2 O, etc.)
• The biosphere is 22% oxygen based on the available volume mainly as an organic molecular component (C _x H _x N _x O _x ) and water molecules
• The hydrosphere is 33% oxygen based on the present volume mainly as a component of water molecules with dissolved molecules including free oxygen and carbonic acid (H _x CO ₃ )
• The lithosphere is 94% oxygen based on the present volume mainly as a silica mineral (SiO ₂ ) and other oxide minerals

Pergerakan oxygen former reservoir difasilitasi sebagian besar oleh adanya oksigen bebas atmosfer. Sumber utama oksigen bebas atmosfer adalah photosintesis, yang menghasilkan gula dan oksigen bebas dari carbon dioxida dan air:

${\ displaystyle \ mathrm {6 \ CO2 6H_2 O energi \ longrightarrow C 6 H 12 O 6 6 \ O2}} Â Â$

Photosynthetic organisms include plant life from land areas as well as phytoplankton from the oceans. Small cyanobacterium sea prochlorococcus was discovered in 1986 and accounts for more than half of photosynthesis from open seas.

Sumber tambahan oksigen bebas atmosfer berasal dari fotolisis, di mana radiasi ultraviolet energi tinggi memecah air atmosfer dan nitrogen oksida menjadi komponen atom. Atom H dan N bebas melarikan say that angkasa, meninggalkan O ₂ di atmosfer:

${\ displaystyle \ mathrm {2 \ H_2 O energi \ longrightarrow 4 \ H O_2}} Â Â$

${\ displaystyle \ mathrm {2 \ N_2 O energi \ longrightarrow 4 \ N O2}} Â Â$

The main way to liberate oxygen from the atmosphere is through respiration and decay, the mechanism by which the lives of animals and bacteria consume oxygen and release carbon dioxide.

Litosfer jugo mengkonsumsi oksigen bebas atmosfer oleh pelapukan kimia dan reaksi permukaan. Contoh kimia pelapukan permukaan adalah pembentukan oksida besi (karat):

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Oxygen also cycles between the biosphere and the lithosphere. Marine organisms in the biosphere create an oxygen-rich calcium carbonate (CaCO _{3) substance. When the organism dies, its shell is deposited on the shallow seabed and buried from time to time to create limestone rocks from the lithosphere. The weathering process initiated by organisms can also liberate oxygen from the lithosphere. Plants and animals extract nutrient minerals from rocks and release oxygen in the process.}

Maps Oxygen cycle

Capacity and flux

The following table offers the approximate capacity and flux of the oxygen cycle cycles. These figures are based primarily on estimates of (Walker, J. C. G.):

Table 1 : The main reservoir involved in the oxygen cycle

Table 2 : Annual profit and loss of atmospheric oxygen (Unit 10 ¹⁰ kg O ₂ per year)

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Ozone

Kehadiran oksigen atmosfer telah menyebabkan pembentukan ozon (O ₃ ) dan lapisan ozon di dalam stratosfer:

${\ displaystyle \ mathrm {O_2 uv ~ light \ longrightarrow 2 ~ O} \ qquad (\ lambda \ lesssim 200 ~ {\ text {nm} })} Â Â$

${\ displaystyle \ mathrm {O O_2 \ longrightarrow O3}} Â Â$

Lapisan ozone sangat penting untuk kehidupan modern karena menyerap radiasi ultraviolet yang berbahaya:

${\ displaystyle \ mathrm {O_3 uv ~ light \ longrightarrow O_2 O} \ qquad (\ lambda \ lesssim 300 ~ {\ text { nm}})} Â Â$

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Reference

• Cloud, P. dan Gibor, A. 1970, Siklus oksigen, Scientific American, September, S. 110-123
• Fasullo, J., Pengganti Ceramah untuk ATOC 3600: Prinsip Iklim, Ceramah tentang siklus oksigen global

, http://paos.colorado.edu/~fasullo/pjw_class/oxygencycle.html

• Morris, RM, OXYSPHERE - Beginner's Guide to Cycling Biogeochemistry from Atmospheric Oxygen, https://web.archive.org/web/20041103093231/http://seis.natsci.csulb.edu/rmorris/oxy/Oxy.htm

Source of the article : Wikipedia