1. Chapter 7 – Ecosystem Ecology

2. © 2013 Pearson Education, Inc. 7.1 Ecosystem Ecology and Biogeochemistry Biosphere –All organisms and nonliving environment Biogeochemical cycle –Flow of matter through ecosystem Elements Water

3. © 2013 Pearson Education, Inc. 7.1 Ecosystem Ecology and Biogeochemistry Biogeochemical cycles –Distribution, abundance, and movement of elements –Pools Parts of ecosystem where element resides –Fluxes Rate element moves

4. © 2013 Pearson Education, Inc. 7.1 Ecosystem Ecology and Biogeochemistry Mass-balance accounting –Process that accounts for the abundance of an element in an ecosystem Capital (of a pool) –Total mass of an element in the pool Equilibrium –When capital in a pool remains constant Residence time –Average time element stays in pool Cycling time –Average time it takes an element move through the cycle

5. © 2013 Pearson Education, Inc. 7.1 Ecosystem Ecology and Biogeochemistry Nutrients –Elements needed to carry out life function –About 25 Macronutrients –Required in relatively large amount Carbon, nitrogen, hydrogen, phosphorous Micronutrients –Required in very small amounts Manganese, boron

6. © 2013 Pearson Education, Inc. 7.2 The Rock Cycle Elements in Earth's crust and mantle cycle –Rocks are converted from one type to another Three categories of rock –Igneous Solidified magma –Sedimentary Sediments (sand, silt) bound by pressure –Metamorphic Heat and pressure transform igneous or sedimentary

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8. 7.3 The Hydrologic Cycle Hydrologic cycle –Distribution and flux of water through biogeochemical system 98% located in ocean Less than 0.001% in atmosphere

9. © 2013 Pearson Education, Inc. 7.3 The Hydrologic Cycle Earth's water Solar energy and gravity drive cycle Includes all three phases of water –Solid ice –Liquid water –Gaseous water vapor

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11. 7.3 The Hydrologic Cycle Precipitation –Moves water from atmosphere to hydrosphere Water returns to atmosphere via –Evaporation –Transpiration Evaporation from plants Water percolates through soil/rock to become groundwater –Aquifers

12. © 2013 Pearson Education, Inc. 7.4 The Carbon Cycle Carbon only 0.032% of atmosphere and lithosphere Most tied in sedimentary rocks 0.0005% cycles through biosphere Carbon essential for life

13. © 2013 Pearson Education, Inc. 7.4 The Carbon Cycle Flux of carbon driven by life Respiration–returns to atmosphere Photosynthesis–pulls from atmosphere –Gross primary production (GPP) Total CO 2 converted each year –Net primary production (NPP) Organic carbon available to consumers –Net ecosystem production (NEP) Net flux of carbon into an ecosystem

14. © 2013 Pearson Education, Inc. Volcanic and hydrothermal emissions Gross primary production Respiration by consumers Respiration by plants Reduced uptake by plants Fossil fuel combustion Anthropogenic sources Deforestation 560 Storage in land plants Storage in consumers Human modifications to the carbon cycle Fossil fuel storage Decomposition 4,000 Storage in soil and soil biota 1,500 Carbon storage in the atmosphere 815 (+3.2/yr) 6 0.9 60 120

16. © 2013 Pearson Education, Inc. 7.4 The Carbon Cycle Most carbon stored in biomass terrestrial –Soil contains large amounts of organic carbon Plant litter, waste, dead organisms Portion not consumed by decomposers remain Carbon pool varies widely –Climate and water affect soil carbon pool

17. © 2013 Pearson Education, Inc. 7.4 The Carbon Cycle Aquatic and marine carbon –CO 2 dissolves in oceans, lakes, and rivers Phytoplankton Carbon used to make shells of marine organisms –Much of this carbon falls as sediment to ocean floor Ocean absorbs carbon

18. © 2013 Pearson Education, Inc. 7.4 The Carbon Cycle Human impacts –Humans have altered carbon cycle –Ecosystem change/destruction reduces NPP –Burning of fossil fuels Releases stored carbon Results in increase of carbon in atmosphere

19. © 2013 Pearson Education, Inc. 7.5 The Nitrogen Cycle Nitrogen –Most abundant element –Small amounts in crust –Microorganisms transform nitrogen gas to usable forms –Plants modify to create essential compounds Amino acids Nucleic acids

20. © 2013 Pearson Education, Inc. 7.5 The Nitrogen Cycle Nitrogen cycles rapidly between atmosphere and biosphere –Nitrogen enters biosphere by nitrogen fixation Bacteria convert N 2 to NH 3 - then other molecules Small amount by lightning –Soil bacteria carry out nitrification Makes nitrogen available to other organisms –Denitrification Bacteria transform nitrates to N 2 gas

21. © 2013 Pearson Education, Inc. 3, 870,000,000 Atmospheric nitrogen (N 2 ) 20 40 80 100 15 110 36 10 Biotic cycling = 8,000 NO x emissions Industry and automobiles Fixation by crops and fertilizer production 1,200 Land plantsConsumers Fossil fuels Groundwater Human modifications Conversion and nitrification by microorganisms Soil organic matter (NH 3 ) 115,000 Runoff 570,000 Inorganic N storage in oceans Sediments and sedimentary rock Atmosphere Fixation Denitrification ProducersConsumers Decomposers Fossil fuel extraction Biological fixation Burial

23. © 2013 Pearson Education, Inc. 7.5 The Nitrogen Cycle Human impacts –Humans have doubled rate of nitrogen fixation –Haber-Bosch process Nonbiological method of nitrogen fixation Source of chemical fertilizer –Excess nitrogen may act as pollutant –Aquatic ecosystems extremely sensitive Eutrophication

24. © 2013 Pearson Education, Inc. 7.6 The Phosphorus Cycle Phosphorous is abundant in crust but absent from atmosphere Organisms use phosphorous as phosphate (PO 4 ) Must be weathered out of sedimentary rock Limiting factor in marine production

25. © 2013 Pearson Education, Inc. 60 Land plants Consumers Decomposition Soil 200,000 Atmosphere Transport of dust and sea spray 10,000 Weathering Rock 12 Mining Erosion Geologic uplift Fertilizers and detergents Pollution Human modifications Runoff Uptake Oceans 90,000 Sediments and sedimentary rock 4,000,000 Burial MARINE CYCLING OF PHOSPHORUS Consumers Producers Decomposers Burial 2 19 1 21

27. © 2013 Pearson Education, Inc. 7.6 The Phosphorus Cycle Human impacts –Humans mine large quantities of phosphorous for fertilizer –Mining activities disrupt ecosystems –Excess phosphorous alters aquatic systems

28. © 2013 Pearson Education, Inc. 7.7 The Sulfur Cycle Sulfur is 0.07% of crust Most chemically bound to rock Weathering and volcanic activity releases usable forms Flux of sulfur into atmosphere high but residence time low

29. © 2013 Pearson Education, Inc. 7.7 The Sulfur Cycle Human impacts –Mining and fossil fuel burning has doubled amount of sulfur released –Source of acid rain

30. © 2013 Pearson Education, Inc. Atmosphere Volcanoes Acid precipitation Dust [8] Fossil fuel combustion Mining Land plants Consumers Decomposition Human modifications Soil Fossil fuels Sea salt and emissions from organisms [164] Uplifting and weathering Runoff Oceans Deposition Seafloor vents 90 150 180 10 130 90 96

32. © 2013 Pearson Education, Inc. 7.8 The Dynamics of Biogeochemical Cycles Biogeochemical cycles vary Seasonal change –Climate affects NPP Disturbance and succession –Plant growth and change after disturbance alters flux and pools