Nitrogen Cycle PDF - Science 9

Nitrogen Cycle Science 9 I can Describe the steps in the nitrogen cycle and the human activities that imitate the nitrogen cycle Discuss the pros and cons of using fertilizers Water cycle With a partner, outline the water cycle. Start with the water in a lake. What path does it take...

Nitrogen Cycle Science 9 I can Describe the steps in the nitrogen cycle and the human activities that imitate the nitrogen cycle Discuss the pros and cons of using fertilizers Water cycle With a partner, outline the water cycle. Start with the water in a lake. What path does it take to go back to the lake? Make sure you include living organisms in your cycle. Nutrient Cycles The Water Cycle Sun’s rays evaporate huge amounts water Water vapour rises in the atmosphere - cools and condenses Clouds form from condensed water droplets Water falls back to the lithosphere as precipitation Water returns and erodes rocks and picks up other materials Absorbed by plants and other organisms - enters biosphere  Nitrogen Nitrogen (N) is an essential component of DNA, RNA, and proteins, the building blocks of life. All organisms require nitrogen to live and grow. The majority (78%) of the Earth’s atmosphere is N2.  The process for changing free nitrogen into Nitrogen nitrogen atoms which can combine with other Fixation elements to form compounds which can be used is called nitrogen fixation This can happen in three ways. Biological 7 Environmental Human  BIOLOGICAL: Nitrogen Cycle Bacteria (called Nitrogen-fixing bacteria) These bacteria form symbiotic relationships with host plants. The bacteria live in nodules found in the roots of the legume family of plants (e.g. beans, peas, and clover) 8 The Nitrogen Cycle Most organisms cannot use nitrogen in the form in which it exists in the air Soil bacteria convert nitrogen into ammonium Soil bacteria convert ammonium into nitrate Plants absorb both forms of nitrogen - nitrate and ammonium Different bacteria convert nitrate back into nitrogen gas atmosphere Excess nitrate and ammonium eventually enter the lithosphere Nitrogen Cycle Video  Nitrogen Uptake The ammonia (NH3) produced by nitrogen-fixing bacteria is usually quickly incorporated into protein and other organic nitrogen compounds (organisms!). It’s either absorbed by a plant, Denitrification - by the bacteria itself, or by another soil organism. NO3 --> N2 Denitrification bacteria Organisms at the top of the food removes nitrogen from chain (like us!) eat and grow, ecosystems, and converts it uptaking nitrogen (that has back to atmospheric N2. already been fixed). This completes the cycle Lightning is also a way to convert nitrogen in the air into nitrogen compounds used by plants HUMAN IMPACT Burning fossil fuels, using synthetic nitrogen fertilizers, and cultivation of legumes 14 all fix nitrogen.  Human Actıvıtıes Many chemicals are released into the air, water and soil every day. Activities such as agriculture, sanitation, water and waste treatment, industrial processes, manufacturing, and transportation can change 15 the concentration of different chemicals and cause an imbalance  Agricultural Activities Farmers must have an understanding of chemistry to produce crops that will give a good yield. Fertilizers ◻ Often, we help plants grow by giving them fertilizer ◻ Fertilizers imitate nitrogen cycle , adding nitrates, ammonia and urea ◻ Phosphorus provided as phosphate compounds ◻ Potash acts as source of potassium 16 Numbers on bag indicate percent of each substance  Fertilizer Pros Cons ◻ Increased plant growth ◻ Fertilizer and water can be ◻ Land not normally suitable an expensive price for productivity for farming, can yield large crops when ◻ Single crop = increased chance of impact by disease ⬜ High yield crops plants ◻ Pesticides can be used to ⬜ Fertilizer used reduce loss of crops, but are ⬜ Properly watered not without cost or environmental impact ◻ Eg: Harmful Algal Blooms Starting with the nitrogen gas in the air, N2, draw a path nitrogen takes through the nitrogen cycle to get back into the atmosphere. Include at least one living organism in this cycle. Write your name at the top and hand it in.