2.2 Nutrient Cycles in Ecosystems Name: Date: (Reference: BC Science 10 pp. 68 to 91) Block: NUTRIENT CYCLING IN THE BIOSPHERE. nutrients: aka.

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1 2.2 Nutrient Cycles in Ecosystems Name: Date: (Reference: BC Science 10 pp. 68 to 91) Block: NUTRIENT CYCLING IN THE BIOSPHERE nutrients: stores: aka Nutrients are accumulated for short or long periods of time in,, and. Biotic processes, such as and abiotic processes, such as can cause nutrients to flow in and out of stores. nutrient cycles: aka Nutrient cycles are nearly in ; the amount of nutrients flowing the stores are nearly the same as the amounts flowing of the stores. Metric measurement units used in the diagrams of nutrient cycles: gigatonne: megatonne: Page 1

2 **Complete Act. 2-2A Understanding Nutrient Cycles THE EFFECT OF HUMAN ACTIVITIES ON NUTRIENT CYCLES Human activities, such as,,,,, and can affect a nutrient cycle by increasing the amounts of nutrients in the cycle than natural biotic and abiotic processes can move them back to the. What does the term biogeochemical cycles mean? THE CARBON, NITROGEN, AND PHOSPHORUS CYCLES Five chemical elements (aka chemical nutrients) that limit the amount and types of life in ecosystems are: Page 2

3 Which of the five chemical elements are cycled between living organisms and the atmosphere? How does phosphorus enter the environment? Health of the ecosystem depends on a of these five nutrients. THE CARBON CYCLE Every living thing contains. Only % of the Earth s crust is carbon. How carbon is stored Short term: Long term: Define the following: sedimentation: Page 3

4 carbonate: Refer to THE CARBON CYCLE on p. 8 of your Data Booklet to answer the following. 1. The greatest carbon stores on earth: 2. The store that contains the least amount of carbon: 3. The greatest carbon exchange (in gigatonnes) and what is responsible : 4. The smallest carbon exchange (in gigatonnes) and what is responsible : 5. What process only releases carbon into the cycle? How carbon is cycled through the ecosystem A variety of natural processes move carbon through ecosystems. These include,,,, and events such as and large scale. Photosynthesis Is an important process in cycling and through ecosystems. Page 4

5 A chemical reaction that converts into. Carbon in the form of in the atmosphere enters through the leaves of plants and reacts with in the presence of to produce energy-rich (carbohydrates) and. o occurs in the of plant cells. The balanced chemical equation for photosynthesis is: Also occurs in some micro-organisms, such as. Makes usable energy for. By eating plants, obtain energy and take into their cells. Cellular Respiration the process in which both and release back into the atmosphere and are converted into and. occurs in the of all living cells. The balanced chemical reaction for cellular respiration is: Page 5

6 Decomposition The importance of decomposition in the carbon cycle: Other ways carbon is cycled through ecosystems The following also play an important part in the carbon cycle, by releasing CO 2 into the atmosphere: the oceans: volcanic activity: decomposing trees: forest fires: HUMAN ACTIVITIES AND THE CARBON CYCLE Human activities have affected the natural carbon cycle in the following ways: Burning fossil fuels: Land clearing/logging: Page 6

7 THE NITROGEN CYCLE Nitrogen is an important component of and. DNA is the abbreviation for. Proteins are essential for within the. In animals, this includes. In plants,. How nitrogen is stored The largest store of nitrogen:, as. Other major stores:,. Smaller stores (on land):,,. How nitrogen is cycled through ecosystems % of the Earth s atmosphere is nitrogen gas. Most organisms cannot use it in this form, so much of the nitrogen cycle involves processes to make nitrogen available to plants, and then in turn to animals Nitrogen Fixation: Page 7

8 Can occur in 3 ways: 1. In the atmosphere: Compounds formed by and can enter soil through. Only small amounts 2. In the soil: Bacteria grow in root nodules and legumes. Symbiosis -> mutualism: plants get, bacterial get. 3. In water bodies: 2. Nitrification: Page 8

9 There are 2 stages involving nitrifying bacteria: Uptake: These nitrogen compounds compose plant. Herbivores and omnivores then eat plants, and use nitrogen for &. How nitrogen is returned to the atmosphere Denitrification: denitrifying bacteria converted ( ) back to ( ). Should be a between the amount of fixed nitrogen and nitrogen returned to the atmosphere. N 2 is also returned to the atmosphere as ammonia (NH 3 ) through How nitrogen is removed from ecosystems Page 9

10 Excess nitrogen dissolves in, enters the, and washes into and. The nitrogen compounds eventually become trapped in, and will not be released again until the rock is. HUMAN ACTIVITIES AND THE NITROGEN CYCLE Due to human activities, the amount of nitrogen in the ecosystem has in the last 50 years. 1. and releases nitrogen oxide (NO) and nitrogen dioxide (NO 2 ). Burning also releases nitrogen compounds that increase in the form of nitric acid (HNO 3 ). 2. often use large amounts of nitrogen-containing. Excess nitrogen is washed away, or leached, into the waterways. leaching: This promotes huge growth in aquatic algae = eutrophication: Page 10

11 Refer to THE NITROGEN CYCLE on p. 11 of your Data Booklet. 1. What two processes take nitrogen from the atmosphere and where do they occur? 2. Locate the two stages of nitrification. Name organism(s) and ions involved in the process. 3. What is involved in uptake? List the ion(s) involved. 4. Locate denitrification on the data table. Name organism(s) and ions involved in the process. 5. Locate and name another natural process that adds nitrogen to the cycle. 6. Locate and name two human activities that add nitrogen to the cycle. THE PHOSPHORUS CYCLE Page 11

12 Phosphorus is essential for in plants and animals Phosphorus is a part of the molecule that carries in living cells. : adensosine triphosphate In plants, phosphorus is important for,, and. In animals, phosphorus and calcium are important for. How phosphorus is stored Phosphorus is not stored in the. it is trapped in (PO 3 4, HPO 2 4, H 2 PO 4 ) found in (Earth s Crust) and in the ocean. Refer to THE PHOSPHORUS CYCLE on p. 9 of your Data Booklet. 1. List the five phosphorus sinks, in order, from largest to smallest? Page 12

13 How phosphorus is cycled through ecosystems Weathering: Two types of weathering: 1. chemical weathering: Ex. 2. physical weathering: After weathering, phosphates are absorbed by, which are then eaten by, and return them to the soil. Weathering doesn t occur until there is geological uplift. Geological uplift: Refer to THE PHOSPHORUS CYCLE on p. 9 of your Data Booklet. 1. List the eight processes, in order, from largest to smallest involved in the flow of phosphorus in the phosphorus cycle? Page 13

14 HUMAN ACTIVITIES AND THE PHOSPHORUS CYCLE Human activities can either add excess phosphorus to the ecosystem or reduce the phosphorus supplies in the ecosystem. Add excess phosphorus: Mined for commercial fertilizers and detergents Extra phosphorus and potassium is added to the ecosystem than it can be put back into natural stores. Can lead to Reduce phosphorus supplies: Slash-and-burn practices Releases phosphate from in the form of. Phosphates accumulate in the soil and is leached from the ash into the water ways, where is settles and becomes to organisms. HOW CHANGES IN NUTRIENT CYCLES AFFECT BIODIVERSITY Any significant changes to any of these nutrients (,,,, and ) can greatly impact the health and biodiversity in an ecosystem 1. Carbon: contributing to carbon in the atmosphere, slight temperature changes and changes in water level can all affect ecosystem biodiversity Page 14

15 If one part of the ecosystem is affected/removed, it affects the rest of the food chain/food web. 2. Nitrogen: can seriously affect biodiversity Some plants better adapted to nitrogen levels than others and therefore out complete the less tolerant species. 3. Phosphorus: can affect phosphorus have reduced algae production in some lakes, which is an important food source for. **Complete CC p. 91 # 1-7, 9-11, 17, 18, 19 Page 15