The Nitrogen Cycle

Master the Nitrogen Cycle! Learn how nitrogen moves through ecosystems with this 9th-grade science worksheet.

Hey Class! Sorry I had to leave in a rush this morning. Please work with your table partners to complete the assignment. I know there are some new students to class, so please SHOW the newbies how to rock a wizer. :) Nitrogen Cycle Video Screencastify Nitrogen Cycle Video Here's a visual of the Nitrogen Cycle. What are the main steps of the nitrogen cycle? How are plants involved in the nitrogen cycle? Plants help in the assimilation of nitrogen when they absorb it from the soil in the form of ammonia, nitrite ions, nitrate ions or ammonium ions to form plant and animal proteins. In leguminous plants such as pea and bean, the symbiotic association with Rhizobium helps to assimilate nitrogen directly in the form of ammonium ions. What role do decomposers play in the nitrogen cycle? Detritus feeders or decomposers such as fungi and bacteria present in the soil convert the dead organic matter of plants or animals back into ammonia (NH3) or ammonium ions (NH4). What is the role of denitrifiers in the nitrogen cycle? Denitrifiers such as Clostridium and Pseudomonas (they're both bacteria) helps in the reduction of nitrates (NO3) or nitrites (NO2), resulting in the escape of gaseous nitrogen which again returns to the cycle. What is the role of lightening in the nitrogen cycle? Lightning with thunderstorm serves as an important source of fixing nitrogen in the atmosphere apart from bacteria mediated nitrogen fixation. Here the energy of lightning breaks atmospheric nitrogen into nitrogen oxides which can then be utilized by plants for assimilation. Why is the nitrogen cycle important in nature? 1- Allowing plants and animals to use nitrogen by converting atmospheric nitrogen to a more chemically available form such as ammonium (NH4), nitrate (NO3), or organic nitrogen2- Enriching the soil through the formation of Nitrates and nitrites which are essential for the cultivation3- Helping in the synthesis of some biomolecules such as amino acids, nucleic acids, and chlorophyll, the building blocks of life4- Decomposing dead plant and animal matter by decomposers which cleans up the environment How do humans impact the nitrogen cycle? Human activities release excess nitrogen into the environment, eventually disturbing the balance of nitrogen in its different reservoirs in two possible ways:- Burning of Fossil Fuels- Use of Nitrogen-Containing Fertilizers How does burning of fossil fuels affect the nitrogen cycle to cause climate change? Burning fossil fuels like coal, petroleum, and natural gas releases excess nitrogen into the environment that accumulates over time. An increase in the concentration of nitrogen is found to affect the climate of the earth by gradually increasing its temperature, causing greenhouse effect and global warming. How does the use of fertilizer affect the nitrogen cycle? When artificial fertilizers containing nitrogen as one of the components are washed away from the agricultural fields, it contaminates the nearby water bodies and also the groundwater making it more difficult for the plants to absorb the nitrogen both for the terrestrial and aquatic plants. Since nitrogen fixation by plants is affected, it affects the nitrogen cycle. A Deeper Look at the Nitrogen Cycle Screencastify If the EMBED video doesn't work. The Nitrogen Cycle is quite complex, so here is a summarization:** reminder: purple words in parentheses are how the word sounds if said out loud. When reading STOP and practice it a few times before continuing. All organisms need nitrogen to make proteins and nucleic (new-clay-ick) acid. Nucleic acids are DNA and RNA. The complex pathway that nitrogen follows within the ecosystem is called the nitrogen cycle. However, most plants can use nitrogen only in the form of nitrate (ny-tray-te). The process of converting nitrogen gas in to nitrate is called nitrogen fixation. Organisms rely on the actions of nitrogen fixing bacteria that are able to transform nitrogen gas into a usable form. Nitrogen-fixing bacteria live in the soil in the roots of some plants, such as beans, peas, clover, and alfalfa.Decomposers (dee-kom-poe-sers) break down dead and decaying organisms and release the nitrogen they contain as ammonia (NH3). When ammonia is in the soil it becomes ammonium (NH4). This process is known as ammonification (ah-mone-if-ah-kay-shon). Through ammonification, nitrogen that would otherwise be lost is reintroduced into the ecosystem. Bacteria in the soil take up the ammonium and react it with oxygen to form nitrites (ny-tri-ts)(NO2), and nitrates (NO3). This process is called nitrification (ny-try-fih-kay-shon). The erosion of nitrate-rich rocks also releases nitrates into an ecosystem. Plants use nitrates to form amino acids. Nitrogen is returned to the atmosphere through denitrification (dee-ny-try-fih-kay-shon). Denitrification occurs when anaerobic (anna-row-bik) bacteria, which are bacteria that can live both with and without oxygen, break down nitrates and release nitrogen back into the atmosphere. 1. When decomposers break down dead and decaying organisms and release the nitrogen they contain, what is it released as? ammonium ammonia ammonide ammonous 2. What does ammonia become when it is in the soil? ammonium ammonia ammonide ammonous 3. What is the process of NH3 becoming NH4 is called? nitricication ammonification notification ammonia transfer 4. Most plants can only use nitrogen in what form? nitrum nitrous pure nitrogen nitrate 5. What is the process of converting nitrogen gas into nitrate called? Nitrogen Conversion Nitrogen Reaction Nitrogen Respiration Nitrogen Fixation 6. What is the role of nitrogen-fixing bacteria? they transform nitrogen gas into a usable form they release nitrogen gas from plants they create nitrogen they transform nitrogen gas into an unusable form 7. Bacteria in the soil takes up ammonium and react it with _ to form nitrate and nitrites. carbon nitrogen oxygen fluorine 8. Where do nitrogen-fixing bacteria live? in the air in the soil in roots of plants in the soil in leaves of plants in animals 9. All organisms need _ to make proteins and amino acids. nitrogen oxygen carbon phosphorous A more detailed look at the Nitrogen Cycle RAFT: Be the Molecule Just like you became a Carbon atom and passed through the Carbon Cycle you are now going to become a Nitrogen atom and pass throughout the Nitrogen Cycle. Using the images in today's lesson as well as knowledge gained, start anywhere you would like and track your movement through 5 locations. Don't just tell me where you went though, tell me why you went there! Reflection