Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Nutrient Cycles Nitrogen and Phosphorus Step 1: Nitrogen fixation •Since nitrogen doesn’t naturally react with other molecules, several sources must fixes gaseous nitrogen (N2 ) to ammonia (NH3 ) requiring intense heat, pressure and energy •Bacteria (use the enzyme nitrogenase) and are found in the roots (nodules) of legumes such as beans or peas or under oxygen rich slime on other roots. •Burning fossil fuels •Volcanic eruptions •Lightning •Industrial manufacturing of fertilizers •Cyanobacteria- aquatic bacteria that fix oxygen in heterocysts (oxygen rich cells) Step 1: Nitrogen fixation: transfers nitrogen from the air (78%) to the soil Accomplished by: bacteria found in legume (bean) roots, volcanoes, burning fossil fuels, lightning, ocean bacteria, and fertilizers Step 2: Nitrification • Soil bacteria convert ammonia (NH4) to ammonium (NH3) in two steps in order to create energy for themselves: Chemosynthesis! Step 1: Nitrogen fixation: transfers nitrogen from the air to the soil Accomplished by: bacteria found in legume (bean) roots, volcanoes, burning fossil fuels, lightning, cyanobacteria, fertilizers Step 2: Nitrification: bacteria use the nitrogen for chemosynthesis and convert it to a form that animals and plants can use. Step 3: Assimilation •Plant roots absorb nitrate ammonia or ammonium and incorporate them into proteins and nucleic acids •Animals that eat plants covert these proteins and nucleic acids to animal forms •Example- folic acid Step 2: Nitrification: bacteria change ammonia to ammonium Step 3: Assimilation: plants and animals absorb ammonium from their food sources and convert it to nucleic acids (DNA or RNA) and protein Step 4: Ammonification •Organisms covert glucose to energy and create a waste product of ammonia •Organisms convert this to urine. •It is also absorbed in the soil when an animal dies. •Bacteria recycle the ammonia for nitrification or assimilation Step 2: Nitrification: bacteria change ammonia to ammonium Step 3: Assimilation: plants and animals absorb ammonium from their food sources and convert it to nucleic acids and protein Step 4: Ammonification: animals create nitrogen-containing urine as a waste product which returns to the soil and is recycled by bacteria back to step 2 Step 5: Denitrification •Nitrate is reduced to gaseous nitrogen and returns to the atmosphere •Denitrifying (anaerobic) bacteria reverse the process of nitrogen fixation deep in the soil Step 3: Assimilation: plants and animals absorb ammonium from their food sources and convert it to nucleic acids and protein Step 4: Ammonification: animals create nitrogen-containing urine as a waste product which returns to the soil and is recycled by bacteria back to step 2 Step 5: Denitrification: anaerobic bacteria ingest nitrogen products in the soil and convert it to a gas. Human Influence: •Agriculture- fertilizers produced from nitrogen gas are used to increase crop yields but add too much nitrogen to the earth. •When it enters ponds and lakes, the fertilizer increases algae growth… the overgrowth (eutrophication) dies and settles on the bottom of the body of water. Then bacteria decompose it, using all of the available oxygen dissolved in the water. This causes other aquatic life to suffocate. •Leach through soil and contaminate groundwater. •Burning fossil fuels adds more to the atmosphere causing photochemical smog, global warming and acid rain. Step 4: Ammonification: animals create nitrogen-containing urine as a waste product which returns to the soil and is recycled by bacteria back to step 2 Step 5: Denitrification: anaerobic bacteria ingest nitrogen products in the soil and convert it to a gas. Human Influence: agriculture (causes algae blooms, kills fish and fertilizers leach in soil contaminating groundwater), burning fossil fuels causes air pollution The Phosphorus Cycle The phosphorus cycle has two loops or circuits◦ Rocks with phosphorus contained in them weather and erode to become soil. 1. If the soil stays on land, it will be used by plants, passed to animals and returned to the soil via decomposition. 2. If the soil is compressed over time, it will become sedimentary rock, again. …or it could be washed into bodies of water where it will become sediment on the seafloor The Phosphorus Cycle Phosphorus is an important nutrient for plants and animals ◦ Used by cells to make ATP and DNA It must be present in soil for plant growth Too much can also cause problems- it can be toxic in high amounts The Phosphorus Cycle The phosphorus cycle does not involve the atmospherePhosphorus is found in the: • Ocean- dissolved in the water •Ocean bottom as sediments •Land soils- carried during erosion •Plants and animals Erosion of rock releases phosphorus into the soil for plant roots The Phosphorus Cycle Inside cells, it is used to make nucleic acids and ATP Decomposers recycle waste products The Phosphorus Cycle Differences between phosphorus and other matter cycles: • the atmosphere is not involved •Phosphate can be “lost” when it settles to the bottom of the ocean it may not be used for millions of years •Once in the aquatic system, it rarely returns back to land. The Phosphorus Cycle Human Influence: 1. Humans spread phosphorus more through agriculture and shipments of food around the country- causing loses of it on crops. More is added through fertilizers. 2. Human waste (sewage) is not treated for phosphorus so it is concentrated in rivers and lakes. 3. Phosphorus is lost by deforestation and development. The Phosphorus Cycle Description of the phosphorus cycle: After rock is weathered and erodes it will: 1. 2. Importance to phosphorus to plants and animals: Differences between this cycle and other nutrient cycles Human influences: The Phosphorus Cycle Step 1: Nitrogen fixation: Accomplished by: Step 2: Nitrification: Step 3: Assimilation: Step 4: Ammonification: Step 5: Denitrification Human Influence