The Nitrogen Cycle?

Question

Can someone explain the nitrogen cycle to me?

I have to write a story from the role of a molecule or element that circulates through the Nitrogen cycle.
I have no idea what to do or write about. Any help is greatly appreciated.

Answer 1

Nitrogen is in the air we breath. This nitrogen is in a very stable form that is not usable yet all living things need nitrogen. This means it must be 'fixed' into a usable or reactive form. Usable means it can bind to other elements like hydrogen, oxygen or carbon. This way animals and plants can use it to make amino acids to construct proteins. Animals have it easy they just eat plants or each other to get their nitrogen in forms they can use. Plants have to trade for it.
Plants can go into symbiosis with fungi that break down dead plants & animals for the nitrogen or with bacteria that takes nitrogen from the atmosphere.
Fungi, mycorrhizae, take forest litter containing complex organic nitrogen forms and digest it. The fungus grows along with plant roots and offers the usable nitrogen and other nutrients to the plant. In return the fungus obtains simple carbohydrates that are produced by the plant specifically for the fungus. Plants get nutrients they are unable to collect for them selves in exchange for carbohydrates the fungus cannot make for themselves.
Bacteria are the other way plants obtain usable nitrogen. Most naturally occurring reactive nitrogen comes originally from nitrogen fixation by bacteria. These types of bacteria can be loose in the soil or in symbiosis with plants.
Symbiotic bacteria also get the carbohydrates from plants in exchange for reactive nitrogen in these relationships. These bacteria live in the plants roots in special nodules. Plants capable of this are legumes like peas, soy, black locust trees, alfalfa etc. and other plants like alder trees.
The free living nitrogen fixing bacteria that are loose in the soil are followed by nitrifying bacteria that convert ammonia to nitrite or nitrate, forms plants can use but are also very mobile so can be washed out of soil into groundwater then into reservoirs.
This is nitrogen fixing followed by nitrification.
N2 -> ammonium (NH4+) -> nitrite ( NO2- ) -> nitrate ( NO3- )
All of these interactions take place in the root zone called the rhizosphere.
Lightning is another way atmospheric nitrogen gets into the soil for use. Lightning converts oxygen (O2) and nitrogen (N2) to nitric oxide (NO), which oxidizes to nitrogen dioxide (NO2), then to nitric acid (HNO3). This is carried into the soil with rain.

Answer 2

This is a very good question and should get 15 answers but it won't. Not enough people interested in botany it seems. I have this link and just look at the diagram. Forget about the text for now. That is no better to you than a text book is. Give me a second to review the chart once more (the should be reviewed numerous times) and I can quickly update this if it lets me...

Let's start with plants. Plants die, there are decomposers that covert plant parts in ammonification, I need another look here to walk you through it...okay, then you have nitrifying bacteria that convert the nitrogen from solid to gas back into the atmosphere, but that is just one direction that it can go. There's another direction there the nitrogen cycle goes. Okay I see nitrogen fixating bacteria there NOT TO BE CONFUSED with the nitrifying bacteria from before. The nitrogen fixating bacteria turns it from gas to solid. Nitrifying ones solid to gas, I believe.

Just the link itself is no good if there's noone to walk you through it. Study it for ten or twenty minutes.

Answer 3

which do you think is most important to the overall health of the biosphere? and why? Carbon Cycle in the atmosphere affects the absorption and reflection of ultraviolet lights.The Co2 in ppm will affect global temperatures

Answer 4

nitrogen cycle:

circulation of nitrogen in various forms through nature. Nitrogen, a component of proteins and nucleic acids, is essential to life on Earth. Although 78 percent by volume of the atmosphere is nitrogen gas, this abundant reservoir exists in a form unusable by most organisms. Through a series of microbial transformations, however, nitrogen is made available to plants, which in turn ultimately sustain all animal life. The steps, which are not altogether sequential, fall into the following classifications: nitrogen fixation, nitrogen assimilation, ammonification, nitrification, and denitrification.

Nitrogen fixation, in which nitrogen gas is converted into inorganic nitrogen compounds, is mostly (90 percent) accomplished by certain bacteria and blue-green algae (see nitrogen fixation). A much smaller amount of free nitrogen is fixed by abiotic means (e.g., lightning, ultraviolet radiation, electrical equipment) and by conversion to ammonia through the Haber-Bosch process (q.v.).

Nitrates and ammonia resulting from nitrogen fixation are assimilated into the specific tissue compounds of algae and higher plants. Animals then ingest these algae and plants, converting them into their own body compounds.

The remains of all living things—and their waste products—are decomposed by microorganisms in the process of ammonification, which yields ammonia. (Under anaerobic, or oxygen-free, conditions foul-smelling putrefactive products may appear, but they too are converted to ammonia in time.) Ammonia can leave the soil or be converted into other nitrogen compounds, depending in part on soil conditions.

Nitrification, a process carried out by nitrifying bacteria (q.v.), transforms soil ammonia into nitrates, which plants can incorporate into their own tissues.

Nitrates also are metabolized by denitrifying bacteria (q.v.), which are especially active in water-logged, anaerobic soils. The action of these bacteria tends to deplete soil nitrates, forming free atmospheric nitrogen.





carbon cycle:

also called carbon–nitrogen cycle sequence of thermonuclear reactions that provides most of the energy radiated by the hotter stars. It is only a minor source of energy for the Sun and does not operate at all in very cool stars. Four hydrogen nuclei are in effect converted into one helium nucleus, a fraction of the mass being released as energy (according to the law of mass–energy equivalence, E = mc2). The German-U.S. physicist Hans Bethe, in 1938, first described the process.

The reactions are as follows: a carbon-12 (12C) nucleus captures a hydrogen nucleus (1H, a proton) to form a nucleus of nitrogen-13 (13N); a gamma ray (γ) is emitted in the process. The nitrogen-13 nucleus emits a positive electron (positron, e+) and becomes carbon-13 (13C). This nucleus captures another proton, becomes nitrogen-14 (14N), and emits another gamma ray. The nitrogen-14 captures a proton to form oxygen-15 (15O); the resulting nucleus ejects a positron as above and is thereby transformed to nitrogen-15 (15N). Eventually, the nitrogen-15 nucleus captures a fast-moving proton and breaks down into a carbon-12 nucleus plus a helium nucleus (alpha particle) of mass 4 (4He).