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3-4 What Happens to Matter in an Ecosystem?
Concept 3-4 Matter, in the form of nutrients, cycles within and among ecosystems and the biosphere, and human activities are altering these chemical cycles.
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Nutrients Cycle in the Biosphere
Matter and nutrients cycle through ecosystems in what we call __________________ cycles or _______________ cycles Hydrologic (water) Carbon Nitrogen Phosphorus Sulfur Nutrients may accumulate and ____________ in a portion of a cycle for a period of time These storage sites, like the atmosphere and the ocean, are called ____________________ biogeochemical nutrient remain reservoirs
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Water Cycles through the Biosphere
Collects, purifies, and distributes earth’s fixed water supply three major processes ___________________...liquid water to vapor ___________________...rain, snow, sleet, dew ___________________...evaporation from a plant Precipitation becomes surface _______________...which flows into streams, lakes, oceans…etc. Water may be stored as… Large bodies of water _________________ Ground water in underground __________________ evaporation precipitation transpiration runoff glaciers aquifers
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Figure 3.16: Natural capital.
Condensation Condensation Ice and snow Transpiration from plants Precipitation to land Evaporation of surface water Evaporation from ocean Runoff Lakes and reservoirs Precipitation to ocean Runoff Increased runoff on land covered with crops, buildings and pavement Infiltration and percolation into aquifer Increased runoff from cutting forests and filling wetlands Runoff Groundwater in aquifers Overpumping of aquifers Figure 3.16: Natural capital. This diagram is a simplified model of the water cycle, or hydrologic cycle, in which water circulates in various physical forms within the biosphere. Major harmful impacts of human activities are shown by the red arrows and boxes. Question: What are three ways in which your lifestyle directly or indirectly affects the hydrologic cycle? Water pollution Runoff Ocean Natural process Natural reservoir Human impacts Natural pathway Pathway affected by human activities Fig. 3-16, p. 67
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Water Cycles through the Biosphere
Alteration of the hydrologic cycle by humans Withdrawal of large amounts of _________________ at rates faster than nature can replace it (evaporation acts a natural distillation process that removes impurities from water) Clearing _______________...increases runoff, reduces infiltration to groundwater supplies, accelerates erosion Increased ______________ when wetlands are drained for farming or urban development freshwater vegetation flooding
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Water Erodes Rock in Antelope Canyon
Figure 3.18: Water flowing over the earth’s surfaces for millions of years played a major role in the formation of the Antelope Canyon in the U.S. state of Arizona. Fig. 3-18, p. 69
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Science Focus: Water’s Unique Properties
Water has unique properties due to hydrogen bonds _______________ water molecules: ________ boiling point: 100˚C Exists as a liquid over a _________ ___________ of temperature Changes temperature _________ (heat storage helps to moderate earth’s temp.) Adhesion and cohesion between High large range slowly
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Science Focus: Water’s Unique Properties
Water has unique properties due to hydrogen bonds ______________ water molecules: ______________ as it freezes (floats during cold winters) ___________ (dissolves nutrients) Filters out harmful _______ (protects aquatic life) between Expands Solvent UV
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Carbon Cycle Depends on Photosynthesis and Respiration
Carbon is the basis for all of our _______________ compounds…found in all living things Link between __________________ in producers and ____________________ in producers, consumers, and decomposers CO2 is also released through the __________________ of dead bodies…if this occurs in water CO2 may be stored in bottom sediment Dead organisms/fossils in the ground may be _____________ over time and turned into _______________ organic photosynthesis respiration decomposition compacted fossil fuels
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Carbon dioxide in atmosphere Respiration
Photosynthesis Animals (consumers) Burning fossil fuels Diffusion Forest fires Plants (producers) Deforestation Transportation Respiration Carbon in plants (producers) Carbon dioxide dissolved in ocean Carbon in animals (consumers) Decomposition Carbon in fossil fuels Marine food webs Producers, consumers, decomposers Figure 3.19: Natural capital. This simplified model illustrates the circulation of various chemical forms of carbon in the global carbon cycle, with major harmful impacts of human activities shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the carbon cycle? Carbon in limestone or dolomite sediments Compaction Process Reservoir Pathway affected by humans Natural pathway Fig. 3-19, p. 70
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Carbon Cycle Depends on Photosynthesis and Respiration
Humans are adding CO2 to the atmosphere at a faster rate through Tree clearing…less trees to use CO2 Burning of fossil fuels…part of our carbon footprint Increasing atmospheric CO2 at a faster than normal rate will enhance the greenhouse effect and may alter our ________________ climate
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Increase in Atmospheric Carbon Dioxide, 1960-2009
Figure 14 This graph shows the atmospheric concentration of carbon dioxide (cO2) measured at a major atmospheric research center in Mauna Loa, Hawaii, 1960–2009. The annual fluctuation in CO2 values occurs because land plants take up varying amounts of CO2 in different seasons. (Data from Scripps Institute of Oceanography, 2010, and U.S. Energy Information Agency, 2010) Data from Scripps Institute of Oceanography, 2010, and U.S. Energy Information Agency, 2010 Supplement 9, Fig 14
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Nitrogen Cycles through the Biosphere: Bacteria in Action (1)
Nitrogen gas, ______, makes up 70% of our atmosphere Nitrogen is a major component of our _______ and ___________...but plants and animals cannot use nitrogen gas directly Two major process convert or ______ nitrogen for us… Nitrogen fixed by electrical discharges or ____________ Nitrogen fixed by specialized _________________ N2 DNA proteins fix lightning bacteria
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Nitrogen Cycles through the Biosphere: Bacteria in Action (1)
Nitrogen fixing bacteria are found in our ________ and also as blue-green algae, ________________, in aquatic environments Nitrogen fixation Bacteria combine gaseous nitrogen (N2) with _______________ to make _____________ (NH3) and _________________ ions (NH4+) Nitrification Soil bacteria change ammonia and ammonium ions to ______________ ions (NO3-)…taken up easily in roots Denitrification Nitrate ions converted back to nitrogen _________ which is eventually released into the atmosphere soil cyanobacteria hydrogen ammonia ammonium nitrate gas
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Nitrates from fertilizer runoff and decomposition
Process Nitrogen in atmosphere Denitrification by bacteria Reservoir Nitrification by bacteria Pathway affected by humans Natural pathway Nitrogen in animals (consumers) Electrical storms Nitrogen oxides from burning fuel and using inorganic fertilizers Volcanic activity Nitrogen in plants (producers) Decomposition Nitrates from fertilizer runoff and decomposition Uptake by plants Figure 3.20: Natural capital. This diagram is a simplified model of the circulation of various chemical forms of nitrogen in the nitrogen cycle in a terrestrial ecosystem, with major harmful human impacts shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the nitrogen cycle? Nitrate in soil Nitrogen loss to deep ocean sediments Nitrogen in ocean sediments Bacteria Ammonia in soil Fig. 3-20, p. 71
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Nitrogen Cycles through the Biosphere: Bacteria in Action (2)
Human intervention in the nitrogen cycle Additional NO and N2O in atmosphere from burning fossil fuels; also causes ____________________ N2O released to atmosphere from bacteria acting on ______________..acts as a greenhouse gas Released to the atmosphere through ________________ of forest, grasslands, and wetlands Add excess nitrates to bodies of water through fertilizers and agricultural __________ Remove nitrogen from our _______________ anytime we harvest crops acid rain (deposition) fertilizers destruction run-off topsoil
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Human Input of Nitrogen into the Environment
Figure 16 Global trends in the annual inputs of nitrogen into the environment from human activities, with projections to 2050, are shown in this graph. (Data from 2005 Millennium Ecosystem Assessmentt) Data from 2005 Millennium Ecosystem Assessment Supplement 9, Fig 16
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Phosphorus Cycles through the Biosphere
Cycles through water, the earth’s crust, and living organisms…the only cycle we are studying that does NOT enter the ___________________ __________ cycle compared to the water, carbon, and nitrogen cycles phosphorus, in phosphate _______ typically gets trapped in __________ formations and cannot reenter the soil or water until the rock __________ away Phosphorus compounds (mostly ____________, PO43- )… act as a _____________ factor for plant growth Are components of our ___________________ atmosphere Slow salts rock erodes phosphates limiting nucleic acids
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Pathway affected by humans
Process Reservoir Pathway affected by humans Natural pathway Phosphates in sewage Phosphates in fertilizer Plate tectonics Phosphates in mining waste Runoff Runoff Sea birds Runoff Phosphate in rock (fossil bones, guano) Erosion Ocean food webs Animals (consumers) Phosphate dissolved in water Phosphate in shallow ocean sediments Phosphate in deep ocean sediments Figure 3.21: Natural capital. This is a simplified model of the circulation of various chemical forms of phosphorus (mostly phosphates) in the phosphorus cycle, with major harmful human impacts shown by the red arrows. Question: What are three ways in which you directly or indirectly affect the phosphorus cycle? Plants (producers) Bacteria Fig. 3-21, p. 73
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Phosphorus Cycles through the Biosphere
Impact of human activities Clearing forests and ______________ phosphate levels in soil Removing large amounts of phosphate from the earth to _________________ fertilizers Erosion leaches phosphates into streams….producer _____________ We do not have that much phosphate in our __________…and our actions are removing more and more of it reducing produce explosion soil
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Sulfur Cycles through the Biosphere
Sulfur found in organisms (proteins), ocean sediments, soil, rocks, and fossil fuels Much of our sulfur is stored underground in the form of ________________ (SO42-) Released naturally into the atmosphere through volcanoes ____________________ H2S ____________________SO2 Human activities affect the sulfur cycle Burn sulfur-containing coal and oil…leads to ________________ Refine sulfur-containing petroleum to make _______________ Convert sulfur-containing metallic mineral ores to metals that we _______ or use...copper, lead, zinc sulfates hydrogen sulfide Sulfur dioxide acid rain gasoline need
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Sulfur dioxide in atmosphere
Sulfuric acid and Sulfate deposited as acid rain Burning coal Refining fossil fuels Smelting Sulfur in animals (consumers) Dimethyl sulfide a bacteria byproduct Sulfur in plants (producers) Mining and extraction Uptake by plants Sulfur in ocean sediments Figure 3.22: Natural capital. This is a simplified model of the circulation of various chemical forms of sulfur in the sulfur cycle, with major harmful impacts of human activities shown by the red arrows. Question: What are three ways in which your lifestyle directly or indirectly affects the sulfur cycle? Decay Decay Process Sulfur in soil, rock and fossil fuels Reservoir Pathway affected by humans Natural pathway Fig. 3-22, p. 74
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Review Questions Which cycle holds the link between photosynthesis and respiration? Which two cycles are linked to causes of acid rain? Which cycle involves transpiration? Which cycle does not involve the atmosphere? Which two cycles involve fertilizers? Which cycle requires specialized bacteria? Carbon cycle Sulfur and nitrogen water phosphorus Nitrogen and phosphorus nitrogen
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