Environment

PLANTS

THE NITROGEN CYCLEGROUP 4

What is Nitrogen?Nitrogen makes up about 78% of our atmosphere. Nitrogen in the atmosphere it is mostly in the form of N2, which is a compound that plants and animals cannot use.The process of converting nitrogen into compounds that can be used by plants and animals is called the Nitrogen Cycle.

Why we care about nitrogenNitrogen is an essential component of _____________________.The building blocks of life.

DNA, RNA and Proteins

How does atmospheric nitrogen (N2) get changed into a form that can be used by most living organisms? By traveling through one of the Five processes in the Nitrogen Cycle! Nitrogen Cycle(1) Nitrogen Fixation(4) Ammonification(2) Nitrification(5) Denitrification(3) Assimilation

Process 1: Nitrogen FixationNitrogen Fixation is the process in which the N2 compound in the atmosphere breaks and combines with other compounds. The nitrogen is fixed when it combines with hydrogen or oxygen.

NNHNHHN2Ammonia (NH3) Nitrous Oxide (N2O)

Three ways to fix NitrogenMain process: Special bacteria convert the nitrogen gas (N2) to ammonia (NH3), which only some plants can use (peas, beans). Lightning strikes convert N2 to N2O or NO3.

Industrial production. Chemical manipulation turns N2 into NH3 (Fertilizer)

Process 2: NitrificationNitrification is the process that converts ammonia (NH3) into nitrites (NO2) and nitrates (NO3) which most plants can use.Note: Ammonia comes from both nitrogen fixation and ammonification

How is it done? NNNHHHOOOOOBacteria!

Process 3: AssimilationAssimilation - process by which plants and animals incorporate the ammonia and NO3-, formed through nitrogen fixation and nitrification.

Process 4: AmmonificationAmmonification - After all the living organisms have used the organic nitrogen, decomposer bacteria convert the nitrogen to ammonia.NHHHBacteriaAmmoniaOrganic Nitrogen (proteins)

Process 5: DenitrificationDenitrification: Process in which nitrogen compounds convert back into atmospheric nitrogen (N2 or N2O).The main process is performed by bacteria in the soil. It can also happen by burning fossil fuels.N2ONO3N2

Nitrogen Cycle(4) Denitrification(1) Nitrogen Fixation(2) AmmonificationNitrates in SoilOrganic nitrogen is converted to ammonia.N2NH3NO3N2OAmmonia is converted to nitrites and nitrates.(3) Nitrification

Nitrogen inthe airanimal proteindead plants & animalsurine & fecesammonianitritesnitratesplant madeproteindecomposition by bacteria & fungibacteria(nitrifying bacteria)nitrates absorbeddenitrifyingbacteriaroot nodules(containing nitrogen fixing bacteria)nitrogen fixing planteg pea, cloverbacteria

Human Impact___________________, releases toxic nitrogen compounds into the atmosphere.____________________________ release nitrous oxide into the atmosphere and introduce excess nitrogen into the environment.Remove nitrogen from the soil when we mine it for nitrogen rich __________________________.Discharge of ___________________________ releases excess nitrogen into the water ecosystems which disrupts the aquatic balance and kills fish.

CombustionCommercial Fertilizersmineral depositsmunicipal sewage

Commercial FertilizersAre the ______ contributor of new nitrogen in the nitrogen cycle.Added because nitrogen is a ________________ for plant growth. Problems: hard to apply fertilizer and keep it in one area. Runoff, evaporation, etc.. So farmers apply about ___________________ as they need.Extra nitrogen disrupts the ________________.#1limiting factortwice as muchfood chain

***