“nitrogen cycle”的概念、定义、翻译、参考文献-科学参考

nitrogen cycle

Chemistry

One of the major cycles of chemical elements in the environment. Nitrates in the soil are taken up by plant roots and may then pass along food chains into animals. Decomposing bacteria convert nitrogen-containing compounds (especially ammonia) in plant and animal wastes and dead remains back into nitrates, which are released into the soil and can again be taken up by plants (see nitrification). Though nitrogen is essential to all forms of life, the huge amount present in the atmosphere is not directly available to most organisms (compare carbon cycle). It can, however, be assimilated by some specialized bacteria (see nitrogen fixation) and is thus made available to other organisms indirectly. Lightning flashes also make some nitrogen available to plants by causing the combination of atmospheric nitrogen and oxygen to form oxides of nitrogen, which enter the soil and form nitrates. Some nitrogen is returned from the soil to the atmosphere by denitrifying bacteria (see denitrification).
Nitrogen cycle

Biology

One of the major cycles of chemical elements in the environment (see biogeochemical cycle). Nitrates in the soil are taken up by plant roots and may then pass along food chains into animals. Decomposing bacteria and archaea convert nitrogen-containing compounds (especially ammonia) in plant and animal wastes and dead remains back into nitrates, which are released into the soil and can again be taken up by plants (see nitrification). Though nitrogen is essential to all forms of life, the huge amount present in the atmosphere is not directly available to most organisms (compare carbon cycle). It can, however, be assimilated by some specialized bacteria (see nitrogen fixation) and is thus made available to other organisms indirectly. Lightning flashes also make some nitrogen available to plants by causing the combination of atmospheric nitrogen and oxygen to form oxides of nitrogen, which enter the soil and form nitrates. Some nitrogen is returned from the soil to the atmosphere by denitrifying bacteria (see denitrification). See illustration.
The nitrogen cycle

Geography

The cycling of nitrogen and its compounds through the ecosystem. Most plants obtain the nitrogen they need as inorganic nitrate from the soil solution. Animals receive the required nitrogen they need for metabolism, growth, and reproduction by the consumption of living or dead organic matter containing nitrogen in molecules.
http://www.physicalgeography.net/fundamentals/9s.html Michael Pidwirny on the nitrogen cycle.

单词	nitrogen cycle
释义	nitrogen cycle Chemistry One of the major cycles of chemical elements in the environment. Nitrates in the soil are taken up by plant roots and may then pass along food chains into animals. Decomposing bacteria convert nitrogen-containing compounds (especially ammonia) in plant and animal wastes and dead remains back into nitrates, which are released into the soil and can again be taken up by plants (see nitrification). Though nitrogen is essential to all forms of life, the huge amount present in the atmosphere is not directly available to most organisms (compare carbon cycle). It can, however, be assimilated by some specialized bacteria (see nitrogen fixation) and is thus made available to other organisms indirectly. Lightning flashes also make some nitrogen available to plants by causing the combination of atmospheric nitrogen and oxygen to form oxides of nitrogen, which enter the soil and form nitrates. Some nitrogen is returned from the soil to the atmosphere by denitrifying bacteria (see denitrification). Nitrogen cycle Biology One of the major cycles of chemical elements in the environment (see biogeochemical cycle). Nitrates in the soil are taken up by plant roots and may then pass along food chains into animals. Decomposing bacteria and archaea convert nitrogen-containing compounds (especially ammonia) in plant and animal wastes and dead remains back into nitrates, which are released into the soil and can again be taken up by plants (see nitrification). Though nitrogen is essential to all forms of life, the huge amount present in the atmosphere is not directly available to most organisms (compare carbon cycle). It can, however, be assimilated by some specialized bacteria (see nitrogen fixation) and is thus made available to other organisms indirectly. Lightning flashes also make some nitrogen available to plants by causing the combination of atmospheric nitrogen and oxygen to form oxides of nitrogen, which enter the soil and form nitrates. Some nitrogen is returned from the soil to the atmosphere by denitrifying bacteria (see denitrification). See illustration. The nitrogen cycle Geography The cycling of nitrogen and its compounds through the ecosystem. Most plants obtain the nitrogen they need as inorganic nitrate from the soil solution. Animals receive the required nitrogen they need for metabolism, growth, and reproduction by the consumption of living or dead organic matter containing nitrogen in molecules. http://www.physicalgeography.net/fundamentals/9s.html Michael Pidwirny on the nitrogen cycle.
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