The Nitrogen Cycle

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What is the nitrogen cycle?

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The nitrogen cycle is the biogeochemical cycle by which nitrogen is converted into multiple chemical forms as it circulates among atmospheric, terrestrial, and marine ecosystems.

Front

What are the important processes in the nitrogen cycle?

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The important processes in the nitrogen cycle include fixation, ammonification, nitrification, and denitrification.

Front

What percentage of Earth's atmosphere is atmospheric nitrogen?

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78% of Earth's atmosphere is atmospheric nitrogen.

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Why is atmospheric nitrogen limited for biological use?

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Atmospheric nitrogen has limited availability for biological use, leading to a scarcity of usable nitrogen in many types of ecosystems.

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What human activities have altered the global nitrogen cycle?

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Human activities such as fossil fuel combustion, use of artificial nitrogen fertilizers, and release of nitrogen in wastewater have dramatically altered the global nitrogen cycle.

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How can human modification of the nitrogen cycle affect the environment?

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Human modification of the global nitrogen cycle can negatively affect the natural environment system and also human health.

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What is one source of nitrogen fixed by natural ecosystems?

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Nitrogen fixed by natural ecosystems is one source of reactive nitrogen.

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What is denitrification?

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Denitrification is a process in the nitrogen cycle where nitrogen compounds are reduced and ultimately produce nitrogen gas, which is released into the atmosphere.

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What role does nitrogen availability play in ecosystems?

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Nitrogen availability can affect the rate of key ecosystem processes, including primary production and decomposition.

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What are some sources of reactive nitrogen?

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Sources of reactive nitrogen include industrial fertilizer production, nitrogen fixed by oceans, agricultural crops, and emissions from biomass burning.