Nitrogen & Phosphorus CYcles

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What is the nitrogen cycle?

Back

The nitrogen cycle is the process by which nitrogen is converted between its various chemical forms, including nitrogen fixation, nitrification, denitrification, and ammonification, allowing nitrogen to be used by living organisms.

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What is nitrogen fixation?

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Nitrogen fixation is the process of converting atmospheric nitrogen (N2) into ammonia (NH3) or related compounds, making nitrogen available for plants.

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Why can't plants and animals use nitrogen directly from the air?

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Plants and animals cannot use nitrogen directly from the air because it exists in a gaseous form (N2) that is not chemically reactive and cannot be absorbed by them.

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What role do bacteria play in the nitrogen cycle?

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Bacteria play crucial roles in the nitrogen cycle, including nitrogen fixation (converting N2 to NH3), nitrification (converting NH3 to nitrates), and denitrification (converting nitrates back to N2).

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What is the phosphorus cycle?

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The phosphorus cycle is the process by which phosphorus moves through the lithosphere, hydrosphere, and biosphere, primarily through weathering of rocks, absorption by plants, and return to the soil through decomposition.

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How do plants obtain phosphorus?

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Plants obtain phosphorus from the soil in the form of phosphate ions (PO4^3-), which are released from rocks through weathering.

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What is the primary source of carbon dioxide in the atmosphere?

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The primary source of carbon dioxide in the atmosphere is the burning of fossil fuels, which releases CO2 as a byproduct.

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What is photosynthesis?

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Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy, producing oxygen and glucose from carbon dioxide and water.

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What is denitrification?

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Denitrification is the process by which nitrates (NO3-) are converted back into nitrogen gas (N2), returning nitrogen to the atmosphere and completing the nitrogen cycle.

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What is the role of decomposers in the nitrogen cycle?

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Decomposers break down dead organic matter, releasing nitrogen back into the soil in the form of ammonium (NH4+), which can then be used by plants.