nitrogen fixation

noun

1. any process of combining atmospheric nitrogen with other elements, either by chemical means or by bacterial action: used chiefly in the preparation of fertilizers, industrial products, etc.

2. this process as performed by certain bacteria found in the nodules of leguminous plants, which make the resulting nitrogenous compounds available to their host plants.

nitrogen fixation

noun

1. the conversion of atmospheric nitrogen into nitrogen compounds by certain bacteria, such as Rhizobium in the root nodules of legumes

2. a process, such as the Haber process, in which atmospheric nitrogen is converted into a nitrogen compound, used esp for the manufacture of fertilizer

nitrogen fixation

1. The process by which free nitrogen from the air is combined with other elements to form inorganic compounds, such as ammonium ions, which can then be converted by nitrification into nutrients that can be readily absorbed by plants and other organisms for incorporation into more complex organic compounds. During lighting strikes, the atmosphere's free nitrogen molecules (N ₂) are broken apart and combine with oxygen to form nitrogen oxides that dissolve in rain to form nitric acid; atmospheric nitrogen is also fixed industrially under high pressure and heat to form ammonia, as in the production of fertilizers. Many species of cyanobacteria and certain other forms of bacteria, especially those that live in the roots of legumes, conduct nitrogen fixation as part of their metabolism, using the enzyme nitrogenase to combine nitrogen with hydrogen as ammonia. All living organisms are dependent on nitrogen fixation and would ultimately die without it.

2. See more at nitrogen cycle

Other Word Forms

• nitrogen-fixing adjective

Word History and Origins

Origin of nitrogen fixation¹

First recorded in 1890–95

Example Sentences

Nitrogen-fixing bacteria generate an enzyme called nitrogenase, sometimes referred to as the "fixer" because it carries out nitrogen fixation.

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The team linked algae growth, enhanced nitrogen fixation, and the upwelling of cool, nutrient-rich waters by studying coral cores collected across the Caribbean.

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The researchers found the highest nitrogen fixation rates along the ice edge -- where melting is most intense.

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The Max Planck scientists also wanted to understand how the Caribbean symbionts acquired the genes required for nitrogen fixation genes.

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This dual role of the bacteria in sulfur cycling and nitrogen fixation highlights their importance in coastal ecosystems and their contribution to plant health and growth.

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