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CYCLING MATERIALS WITHIN THE ECOSYSTEM Ch. 6
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Conservation of matter – matter is recycled not created or destroyed. (forms: solid, liquid, gas) In ecosystem matter recycled b/w organisms and abiotic environment Biogeochemical cycles
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Carbon .04% of atmosphere (as CO 2 ) and in all life (organic matter contains carbon) Carbon sinks (reservoirs): atmospheric carbon dioxide, dissolved CO 2 in oceans, organic matter in soil, fossil fuels, some rock, calcium carbonate of ocean shelled organisms, biomass CO 2 main greenhouse gas from human activities
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Carbon cycle Geological cycle: limestone (calcium carbonate rock) dissolves from rainwater and washes carbon to ocean. Settles on sea floor, subducted under by plate tectonics. Heat and pressure releases CO 2 from rock returned by volcanic eruptions. Biological cycle: air/water plants via photosynthesis used as fuel in cellular respiration released in waste and decomposition
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issues Changing quantities in carbon sinks Industrial revolution (~ 1850) – combustion of fossil fuels
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NAME 3 WAYS CARBON GETS RETURNED TO THE ATMOSPHERE
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Check for understanding 4 - I can explain to my peers how carbon cycles between living and nonliving matter and how humans influence the amount of carbon in the atmosphere. 3 - I understand how carbon cycles between living and nonliving matter and how humans influence the amount of carbon in the atmosphere. 2 - I understand how carbon cycles but I need more practice 1 - I am lost about the carbon cycle
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NITROGEN 78% atm. Commonly a limiting factor Atm. Nitrogen (N 2 ) gets “fixed” into ammonia by bacteria in absence of oxygen. Ex: Rhizobium Nitrogen Fixation Nitrification: Ammonia (NH 3 ) nitrite (NO 2 - ) nitrate (NO 3 - ) Plants assimilate nitrogen (various forms) consumers. Living things use it for DNA and protein Ammonification: Waste/dead body decompose back to ammonia (NH 3 ) Denitrification: nitrate (NO 3 - ) atm. Nitrogen (N 2 );
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Issues Fertilizers into water ecosystems = algal growth eutrophication N2O: Greenhouse gas N2O:Destroy ozone Combustion of fossil fuels releases nitrogen and changes atm. N2 into nitrogen oxides. (NO) Photochemical smog injures plant tissues, resp. problems, irritate eyes React with H 2 O to form nitric acid (HNO 3 ) acid deposition – decreased surface water/soil pH (effects discussed later)
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Check for understanding 4 - I can explain to my peers how nitrogen cycles between living and nonliving matter and how humans influence the amount of nitrogen in the atmosphere and in aquatic biomes. 3 - I understand how nitrogen cycles between living and nonliving matter and how humans influence the amount of nitrogen in the atmosphere and in aquatic biomes. 2 - I understand how nitrogen cycles but I need more practice 1 - I am lost about the nitrogen cycle
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PHOSPHORUS Not in atmosphere Eroded from rocks by water plants consumers; decomposers return it to soil Other sinks: ocean floor sediment
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issues Phosphate lost from land Farm soil loses phosphate b/c plants shipped away. Then need phosphate fertilizer for plant growth. Washed down toilets and exit as effluent into water ecosystems. My house
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SULFUR Tiny bit in atmosphere ; part of proteins; bacteria imp. in cycle Major sinks: sedimentary rock and oceans A little: Soil plants animals
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issues Sulfur dioxide/acid deposition: Burning coal releases Smelting of copper, lead, zinc Improvements: scrubbers on smokestacks
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HYDROLOGIC CYCLE 97% seawater; most fresh is frozen Key terms: transpiration, watershed, runoff
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issues Dams Aquifer depletion
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Check for understanding 4 - I can explain to my peers how water, phosphorus, and sulfur cycle between living and nonliving matter and how humans influence the amount of these elements in the atmosphere, on land, and in aquatic biomes. 3 - I understand how water, phosphorus, and sulfur cycle between living and nonliving matter and how humans influence the amount of these elements in the atmosphere, on land, and in aquatic biomes 2 - I understand how water, phosphorus, and sulfur cycle, but I need more practice. 1 - I am lost about at least of the cycles – water, sulfur, phosphorus.
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