The Nitrogen Cycle By Evelynn Liang Janelle Guild

The Nitrogen Cycle By: Evelynn Liang Janelle Guild AP Environmental Science Project

What is Nitrogen? What is nitrogen? -A gaseous element that is abundantly found in the Earth’s atmosphere (takes up about 78% of the atmosphere) -limiting nutrient: when a nutrient is short in supply and limits growth *a lack of nitrogen restricts the growth of the organism. What is it used for? ● growth and reproduction for plants and animals, and is found in amino acids in proteins that make up nucleic acids ● most important pigment needed for photosynthesis

Biotic and Abiotic Factors Biotic Factors: 1. Plants take in nitrogen. 2. Animals eat the plants and obtain nitrogen. 3. Animals that eat those animals obtain the nitrogen also (etc). Abiotic Factors: 1. Man made pollution adds to the nitrogen. 2. Cars and other sources of pollution affect the surroundings *do not necessarily need nitrogen to work or exist

Steps of the Nitrogen Cycle 1. Nitrogen Fixation- process of converting N 2 gas into ammonia (NH 3) Within nitrogen fixation, there are two processes: ● Abiotic Fixation- N 2 is combined with oxygen to form nitrogen oxides such as NO and NO 2 and are carried through the earth’s surface, in the form of rainfall (nitric acid-HNO 3). ● Biological fixation- microorganisms such as aerobic and anaerobic bacteria are found in the roots of legumes and provides ammonia for the plants

Steps of the Nitrogen Cycle Continued…. . . 2. Assimilation- nitrogen-based compounds continues to pass from one organism to another (through consumption) as matter and energy transfers through the ecosystem’s food web. 3. Ammonification-decomposing microorganisms, such as bacteria and fungi breaks down nitrogenous wastes and organic matter found in animal waste and dead plants/animals, and convert it to inorganic ammonia (NH 3) 4. Nitrification- bacteria converts ammonium (HH 4+) into nitrite (NO 2 -) and then into nitrate (NO 3 -) 5. Denitrification- bacteria converts nitrate into gaseous nitrogen (N 2) and becomes lost in the atmosphere

Nitrogen Cycle Diagram

Nitrogen Cycle Video Here is a video that will help you understand more in depth about the concepts and process of the nitrogen cycle. * DON’T WORRY, IT WON’T BE LONG : ) http: //www. pbslearningmedia. org/asset/lsps 07_int_nitrogen/ http: //www. youtube. com/watch? v=XU 3 QMYf. Od. CM

Let’s Play a Game ● ● Please grab a copy of the game. Pick up two pennies and a game piece (each person). Read the instructions. Begin the game. As you’re playing, here are some questions you may want to take notes of: 1. How many cycles you’ve completed? 2. What step of the nitrogen cycle you keep landing on? 3. Did you notice any patterns of any such? http: //apcentral. collegeboard. com/apc/public/repository/nitr ogen-cycling-in-ecosystems. pdf

Human Impacts ★ 1. Adding Nitrogen can reduce biodiversity by 48% because some species could survive under low-nitrogen conditions could no longer compete against larger plants that thrive under high Nitrogen conditions. It can also lead to a nutrient imbalance in trees and changes in forest health. ★ 2. Application of Unused Nitrogen-based fertilizers( usually in the form of Nitrate ) can leach out into soil and make its way into the streams and rivers. ★ 3. Burning of Fossil Fuels cause the nitric oxides to release in the air and combine with other elements that form smog and acid rain which affect the environment by forming ground level ozone which can ruin plant productivity and reduce agricultural yields for important crops like soybean, cotton. Acid rain can destroy crops and cause respiratory problems. ★ 4. Alterations to the Nitrogen Cycle may lead to a risk of parasitic and infectious diseases to humans and wildlife.

Review Questions ★ ★ ★ ★ ★ What are the steps of the Nitrogen Cycle? Why is Nitrogen crucial for sustaining life on earth? What is one way that the Nitrogen Cycle can be disrupted by human activities? What do plants do with the Nitrogen they absorb? A. Kill other plants B. Use it in photosynthesis C. Build Proteins What are the consequences of excess Nitrogen in the ecosystem? How much of Earth’s atmosphere is made up of Nitrogen? Nitrogen is used by plants in the form of? What is one biotic and abiotic factor in the nitrogen cycle? What is a limiting nutrient? What are the two processes within nitrogen fixation?