nitrogen cycle

简明释义

氮循环

英英释义

例句

1.Farmers often monitor the nitrogen cycle 氮循环 to optimize their crop yields.

农民通常监测氮循环 nitrogen cycle 以优化作物产量。

2.Understanding the nitrogen cycle 氮循环 is crucial for improving soil fertility.

理解氮循环 nitrogen cycle 对于提高土壤肥力至关重要。

3.Scientists study the nitrogen cycle 氮循环 to understand how nitrogen moves through ecosystems.

科学家研究氮循环 nitrogen cycle 以了解氮如何在生态系统中移动。

4.The nitrogen cycle 氮循环 involves processes like nitrogen fixation and denitrification.

氮循环 nitrogen cycle 包括氮固定和反硝化等过程。

5.The disruption of the nitrogen cycle 氮循环 can lead to environmental issues such as eutrophication.

干扰氮循环 nitrogen cycle 可能导致富营养化等环境问题。

作文

The nitrogen cycle is a fundamental ecological process that describes the movement of nitrogen through various forms in the environment. Nitrogen is an essential element for all living organisms, as it is a key component of amino acids, proteins, and nucleic acids. However, the atmosphere is composed of about 78% nitrogen gas (N2), which is not directly usable by most living organisms. The nitrogen cycle illustrates how nitrogen is converted into different chemical forms, making it accessible to plants and animals.The cycle begins with nitrogen fixation, a process where atmospheric nitrogen is converted into ammonia (NH3) by certain bacteria, such as those found in the root nodules of legumes. These bacteria possess the enzyme nitrogenase, which enables them to break the strong triple bond of N2 molecules. This conversion is vital because ammonia can be taken up by plants and transformed into organic compounds. Once nitrogen is in a usable form, it enters the soil through various means, including decomposition of organic matter. When plants and animals die or excrete waste, nitrogen compounds are released back into the soil. Decomposers, like bacteria and fungi, play a crucial role in breaking down this organic matter, returning nitrogen to the soil in the form of ammonium (NH4+). This process is known as ammonification.After ammonification, the next step in the nitrogen cycle is nitrification. This process involves the oxidation of ammonium into nitrites (NO2-) and then into nitrates (NO3-), which are also usable by plants. Nitrifying bacteria, such as Nitrosomonas and Nitrobacter, facilitate this transformation. Nitrates are particularly important because they are the primary form of nitrogen that plants absorb from the soil.Plants utilize nitrates to synthesize proteins and other essential compounds. When animals consume these plants, nitrogen is transferred up the food chain. However, the cycle does not stop here; when animals excrete waste or die, nitrogen again returns to the soil, continuing the nitrogen cycle.The final stage of the nitrogen cycle is denitrification, a process carried out by anaerobic bacteria that convert nitrates back into nitrogen gas, which is then released into the atmosphere. This step is crucial in maintaining the balance of nitrogen in the environment, preventing the accumulation of excess nitrates in the soil, which can lead to issues such as water pollution and eutrophication.In summary, the nitrogen cycle is a complex yet essential process that ensures the continuous availability of nitrogen in different forms for living organisms. Understanding this cycle is vital for environmental science, agriculture, and ecology, as it highlights the interconnectedness of life and the importance of maintaining healthy ecosystems. By recognizing the significance of the nitrogen cycle, we can take steps to protect our environment and promote sustainable practices that support the natural processes that sustain life on Earth.

氮循环是一个基本的生态过程，描述了氮在环境中以各种形式的运动。氮是所有生物体必不可少的元素，因为它是氨基酸、蛋白质和核酸的关键组成部分。然而，大气中约有78%的氮气（N2），大多数生物无法直接利用。氮循环展示了氮是如何转化为不同的化学形式，使其可以被植物和动物所利用。这一循环始于氮固定，这是一个将大气氮转化为氨（NH3）的过程，由某些细菌完成，例如生长在豆科植物根瘤中的细菌。这些细菌拥有氮酶，这使得它们能够打破N2分子的强三重键。这一转化至关重要，因为氨可以被植物吸收并转化为有机化合物。一旦氮以可用的形式进入土壤，它就会通过各种方式进入，包括有机物的分解。当植物和动物死亡或排泄废物时，氮化合物会释放回土壤。分解者，如细菌和真菌，在分解这些有机物方面发挥着至关重要的作用，将氮以铵（NH4+）的形式返回土壤。这个过程被称为铵化。在铵化之后，氮循环的下一个步骤是硝化。这个过程涉及将铵氧化成亚硝酸盐（NO2-），然后再转化为硝酸盐（NO3-），这些也是植物可用的。硝化细菌，如Nitrosomonas和Nitrobacter，促进了这一转化。硝酸盐尤其重要，因为它们是植物从土壤中吸收的主要氮源。植物利用硝酸盐合成蛋白质和其他必需化合物。当动物食用这些植物时，氮就会传递到食物链中。然而，循环并未止步；当动物排泄废物或死亡时，氮再次返回土壤，继续氮循环。氮循环的最后阶段是反硝化，这是由厌氧细菌完成的过程，将硝酸盐转化回氮气，然后释放到大气中。这个步骤对于维持环境中氮的平衡至关重要，防止土壤中硝酸盐过量积累，这可能导致水污染和富营养化等问题。总之，氮循环是一个复杂但至关重要的过程，确保氮以不同形式持续可用于生物体。理解这一循环对环境科学、农业和生态学至关重要，因为它突显了生命的相互联系以及维持健康生态系统的重要性。通过认识氮循环的重要性，我们可以采取措施保护我们的环境，促进支持维持地球上生命的自然过程的可持续实践。