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
Ch 7 Environmental Systems and Ecosystem Ecology Part 1: Foundations of Environmental Science PowerPoint® Slides prepared by Jay Withgott and Heidi Marcum Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Study Guide: • The nature of environmental systems • Ecosystems and how living and nonliving entities interact • Flow of Energy and Cycle of Matter • Net Primary Production • The Carbon, Phosphorus, Nitrogen, and Water Cycles • How Plate Tectonics and the Rock Cycle shape the Earth Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Mississippi River entering Gulp of Mexico Central Case: The Gulf of Mexico’s “Dead Zone” - before Hurricane Katrina(2005), & BP Oil Station Explosion(2010) • Gulf of Mexico brings in 600 million kg/year shrimp, fish, and shellfish • Gulf “dead zone”: a region of water so depleted of oxygen that kills or drives away marine organisms • Hypoxia: low concentrations of dissolved oxygen water Normal level: Minimum: 10 ppm 2 ppm Hypoxia: below the level Caused by fertilizer, runoff, sewage Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings ppm: parts/million % = parts/hundread ppm=0.0001 % 10,000 ppm = 1 % The Earth’s systems • System = a network of relationships among parts. Consists of elements or components that interact with and influence one another - Exchange of energy, matter, or information - Receives inputs of energy, matter, or information; processes these inputs; and produces outputs • Systems often show behavior that is hard to predict • Feedback loop = a system’s output serves as input to that same system - A circular process Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Earth Systems System changes (active) Most of earth’s systems are in dynamic equilibrium or steady state – Balanced & stable state Rate of change in one direction equals that in the other. results in no change in net results. (eg. Zero pop. growth) Feedback Negative feedback- change triggers a response that counteracts the changed condition- stabilize the system, common in nature Positive feedback- change triggers a response that intensifies the changing condition drive the system to an extreme, human induced Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Feedback Negative Feedback Stabilize the system Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Positive Feedback Drive to an extreme (Unstable) Understanding requires system considerations • Environmental entities are complex systems that interact with each other - For example, river systems consist of hundreds of smaller tributary subsystems • To solve environmental problems, all appropriate systems must be considered Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Systems are perceived in various ways • Categorizing environmental systems helps make Earth’s dazzling complexity comprehensible • For example, the earth consists of structural spheres - Lithosphere = rock and sediment - Atmosphere = the air - Hydrosphere = liquid, solid or vapor water - Biosphere = all the planet’s living organisms and the abiotic portions of the environment • Boundaries overlap, so the systems interact Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ecology • Biosphere contains earth’s communities, ecosystems and landscapes, and includes: Atmosphere gaseous envelope surrounding earth Hydrosphere - earth’s supply of water Lithosphere - soil and rock of the earth’s crust Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Gulf of Mexico from a systems perspective • Nutrients from fertilizer enter the Mississippi River from Midwestern farms • Fertilizer use has increased, which causes…. • Phytoplankton to grow, then… • Bacteria eat dead phytoplankton and wastes and deplete oxygen, causing… • Fish and other aquatic organisms to suffocate Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Eutrophication • The process of nutrient overenrichment, blooms of algae, increased production of organic matter, and ecosystem degradation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Ecosystems • Ecosystem = all organisms and nonliving entities that occur and interact in a particular area at the same time - Includes abiotic and biotic components - Energy flows and matter cycles among these components • Biological entities are highly intertwined with chemical and physical entities - Interactions and feedback loops Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Systems of interacting entities in ecosystems • Energy from the sun flows in one direction - Energy entering the system is processed and transformed chemical energy(green) & heat energy (red) • Matter is recycled within ecosystem, resulting in outputs such as heat, water flow, and waste products Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Energy & mass(Nutrient) are converted to biomass • Primary production: conversion of solar energy to chemical energy (in sugars) by autotrophs – All photosynthetic output • Gross primary production (GPP): GPP = E(CR) + NPP assimilation of energy by autotrophs = Energy for Cellular Respiration + Biomass (Carbohydrate) • Net primary production (NPP) : energy remaining after respiration, and is used to generate Biomass NPP = GPP - E(CR) - Available as a food for heterotrophs • Secondary production: total biomass that heterotrophs generate by consuming autotrophs • Productivity: rate at which ecosystems generate Biomass normally given in g C/m2/yr Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Photosynthesis and Cellular Respiration Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings NPP variation causes global geographic patterns NPP increases with temperature and precipitation on land, and with light and nutrients in aquatic ecosystems Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Net primary productivity of various ecosystems High net primary productivity = ecosystems whose plants rapidly convert solar energy to biomass Corn, or Potato • Tropical Rainforest: ~ 5 lbs/m2/yr • Temp. g’land. (Midwest) ~ 2 lbs m2/yr • Tundra ~ 1 lbs/m2/yr • Desert ~0.5 lbs/m2/yr 1m2 = 11 ft2 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Nutrients can limit productivity • Nutrients = elements and compounds required for survival that are consume by organisms - Nitrogen, carbon, phosphorus - Stimulate plant production Table 4.1 p89 Composition of Organisms: O 65% C 18.5% H 9.5% N 3.3% Ca 1.5% P 1.0 % • N&P K 0.4% are important for plant S 0.3% and algal growth Others 0.5% Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Dramatic growth of algae in water treated with phosphate Biogeochemical Cycle (Nutrient Cycle) - Nutrients circulate through ecosystems • Physical matter is circulated continually in an ecosystem • Nutrient (biogeochemical) cycle : the movement of nutrients through ecosystems - Atmosphere, hydrosphere, lithosphere, and biosphere • Pools (reservoirs) : where nutrients reside for varying amounts of time • Flux : movement of nutrients among pools, which change over time and are influenced by human activities • Sources :pools that release more nutrients than they accept • Sinks : accept more nutrients than they release Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The carbon cycle • Carbon is found in carbohydrates, fats, proteins, bones • Carbon cycle = describes the routes that carbon atoms take through the environment • Photosynthesis moves carbon from the air to organisms • Respiration returns carbon to the air and oceans • Decomposition returns carbon to the sediment, the largest reservoir of carbon - Ultimately, it may be converted into fossil fuels • The world’s oceans are the second largest reservoir of carbon Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The carbon cycle: amount in Pg (Peta grams) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Humans affect the carbon cycle • Burning fossil fuels moves C from the ground to the air • Cutting forests & burning fields moves carbon from organisms (Biosphere) to the air • Today’s atmospheric carbon dioxide reservoir is the largest in the past 650,000 years - The driving force behind climate change • The missing carbon sink: 1-2 billion metric tons of carbon are unaccounted for - It may be the plants or soils of northern temperate and boreal forests Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The phosphorus cycle • Phosphorus is a key component of cell membranes, DNA, RNA, ATP and ADP, and ? (in an animal) • Phosphorus cycle = describes the routes that phosphorus atoms take through the environment - No significant atmospheric component - Most phosphorus is within rocks and is released by weathering • With naturally low environmental concentrations, phosphorus is a limiting factor for plant growth Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The phosphorus cycle: (in Tg) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Humans affect the phosphorus cycle • Mining rocks for fertilizer moves phosphorus from the soil to water systems - Wastewater discharge also releases phosphorus • Runoff containing phosphorus causes eutrophication of aquatic systems Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The nitrogen cycle • Nitrogen comprises 78% of our atmosphere, and is contained in Proteins, DNA and RNA • Nitrogen cycle = describes the routes that nitrogen atoms take through the environment - N2 gas is inert and cannot be used by organisms • Nitrogen fixation = Nitrogen gas is combined (fixed) with hydrogen by nitrogen-fixing bacteria to become ammonium that can be used by plants N2+3H2 → 2NH3 & 2NH4 + Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Nitrification and denitrification • Nitrification: = that convert ammonium ions first into nitrite ions then into nitrate ions by bacteria NH3 / NH4+- → NO2 - → NO3 - - Plants can take up these ions Animals obtain nitrogen by eating plants or other animals • Denitrification: convert nitrates in soil or water to gaseous nitrogen, releasing it back into the atmosphere by bacteria NO3 - → NO2 - → Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings N2 (the atmosphere) The nitrogen cycle; (in Tg) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Humans affect the nitrogen cycle • Haber-Bosch process = synthetic production of fertilizers by combining nitrogen and hydrogen to synthesize ammonia - Dramatically changed the nitrogen cycle - Humans are fixing as much nitrogen as nature does • Increased emissions of nitrogen-containing greenhouse gases • Calcium and potassium in soil washed out by fertilizers • Acidified water and soils • Moved more nitrogen into plants and terrestrial systems • Reduced biodiversity of plants adapted to low-nitrogen soils • Changed estuaries and coastal ecosystems and fisheries Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Human inputs of nitrogen into the environment Fully half of nitrogen entering the environment is of human origin Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings A law addressing hypoxia in the Gulf • The Harmful Algal Bloom and Hypoxia Research and Control Act (1998) called for an assessment of hypoxia in the Gulf • Solutions outlined included: - Reduce nitrogen fertilizer use in Midwestern farms - Change timing of fertilizer applications to minimize runoff - Use alternative crops - Restore wetlands and create artificial ones - Improve sewage = treatment technologies - Evaluate these approaches Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The hydrologic cycle • Water is essential for biochemical reactions and is involved in nearly every environmental system • Hydrologic cycle = summarizes how liquid, gaseous and solid water flows through the environment - Oceans are the main reservoir • Evaporation = water moves from aquatic and land systems to air • Transpiration = release of water vapor by plants • Precipitation = condensation of water vapor as rain or snow Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Groundwater • Aquifers = underground reservoirs of sponge-like regions of rock and soil that hold … - Groundwater: water found underground beneath layers of soil - Water table: the upper limit of groundwater held in an aquifer - Water may be ancient (thousands of years old) • Groundwater becomes exposed to the air where the water table reaches the surface (wells) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The hydrologic cycle Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Human impacts on hydrologic cycle • Damming rivers increases evaporation and infiltration • Altering the surface and vegetation increases runoff and erosion • Spreading water on agricultural fields depletes rivers, lakes and streams • Removing forests and vegetation reduces transpiration and lowers water tables • Emitting pollutants changes the nature of precipitation - Acid Rain Probelms • The most threatening impact is overdrawing groundwater for drinking, irrigation, and industrial use Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Plate tectonics shapes the Earth - Continental Drift (Wegener, 1880-1930) • Plate tectonics: The motions of regions of Earth’s Lithosphere which drift wrt one another. Underlies earthquakes and volcanoes, and determines the geography of the Earth’s surface. • Crust: thin outer lightweight layer of Earth Asthenosphere: boundary layer where slipping occurs • Mantle: malleable layer on which the crust floats Convection Cells • Core: molten heavy center , made mostly of iron • Average Density of Earth: ~5.5g/cm3 = 5.5 kg/L = 5.5 Mg/m3 = 5.5 ton/m3 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Internal Structure of Earth Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Earth Topography Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Earth Topography World War II: Needed Sea Floor Map for Submarine Warfare Harry Hess, US Naval Officer, History of Ocean Basin, 1962 Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Earth has 15 major tectonic plates Movement of these plates influences climate and evolution Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The effect of mantle convection http://rst.gsfc.nasa.gov/Sect2/Sect2_1b.html Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Earth’s crust is constantly created and destroyed • Divergent plate boundaries = magma surging upward to the surface divides plates and pushes them apart, creating new crust as it cools and spreads • Transform plate boundary = two plates meet, slipping and grinding alongside one another - Friction spawns earthquakes along slip-strike faults Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Tectonic plates can collide • Convergent plate boundaries = where plates collide • Subduction = one plate of crust may slide beneath another - Magma erupts through the surface in volcanoes • Two colliding plates of continental crust may lift material from both plates - Resulted in the Himalaya and Appalachian mountains Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Locations of Earth’s Volcanos Occurs mostly along the plate boundaries Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The rock cycle • Rock cycle = The heating, melting, cooling, breaking and reassembling of rocks and minerals • Rocks help determine soil chemistry, which influences ecosystems • Helps us appreciate the formation and conservation of soils, mineral resources, fossil fuels, and other natural resources Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Igneous rock • Magma = the molten, liquid state of rock • Lava = magma released from the lithosphere • Igneous rock = forms when magma cools • Intrusive rock = magma that cools slowly well below Earth’s surface (i.e., granite) • Extrusive rock = magma ejected from a volcano (i.e., basalt) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Sedimentary rock: Limestone • Sediments = particles of rock are blown by wind or washed away by water • Sedimentary rock = dissolved minerals seep through sediment layers and crystallize and bind sediment particles together: • Lithification = formation of rock through the processes of compaction, binding, and crystallization Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Formation of sedimentary rock through chemical and physical processes • Some rock is formed by chemical means when rocks dissolve and their components crystallize to form new rock: primarily by chemical processes - limestone (CaCO3 ) - rock salt (NaCl) • Other rocks are formed when layers of sediment compress and physically bond to one another: primarily by physical processes - shale (from silt & clay particles) - sandstone (from sand), - conglomerate (from gravels), coal (organic) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Metamorphic rock: Marble • Metamorphic rock: great heat or pressure on a rock changes its form • Temperatures is high enough to reshape crystals and change its appearance and physical properties Marble: heated and pressurized limestone Slate: heated and metamorphosed shale Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Pangaea: the supercontinent At least twice in Earth’s history, all landmasses were joined in one supercontinent Pangaea: 225 Myr BP Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Pangaea: the supercontinent Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Fossil Evidence for Plate Tectonics http://www.clemson.edu/caah/history/FacultyPages/PamMack/lec124/originalnature.html Fossils from Extinct Animals and Plants of the Triassic Periods (245~210 M yr BP) History Written by Mother Nature http://pubs.usgs.gov/gip/dynamic/historical.html Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Earth’s crust is constantly created and destroyed • Divergent plate boundaries = magma surging upward to the surface divides plates and pushes them apart, creating new crust as it cools and spreads • Transform plate boundary = two plates meet, slipping and grinding alongside one another - Friction spawns earthquakes along slip-strike faults Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Mid-Atlantic Ridge: Oceanic Divergent Plates Divergence of South American Plate and African Plate http://www.serg.unicam.it/Boundaries.html Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/ tectonics_landforms/magnetic_stripe_formation.htm Tectonic plates can collide • Convergent plate boundaries = where plates collide • Subduction = one plate of crust may slide beneath another - Magma erupts through the surface in volcanoes • Two colliding plates of continental crust may lift material from both plates - Resulted in the Himalaya and Appalachian mountains Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The effect of mantle convection http://rst.gsfc.nasa.gov/Sect2/Sect2_1b.html Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Mid-Atlantic Ridge: Oceanic Divergent Plates Divergence of South American Plate and African Plate http://www.serg.unicam.it/Boundaries.html Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/ tectonics_landforms/magnetic_stripe_formation.htm Transform Plate Boundaries: Strike-slip fault Pacific Plate and N American Plate 1906 San Francisco earthquake http://pubs.usgs.gov/gip/earthq3/along2.html Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings San Andreas Fault http://pubs.usgs.gov/gip/dynamic/San_Andreas.html Convergent continental plates: Himalayan Mountains Eurasian Plate & Indian-Australian Plate http://www.travel-himalayas.com/himalayas-pictures/gifs/spiti-ladakh-b.jpg Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings http://pubs.usgs.gov/gip/dynamic/himalaya.html Convergent plates with subduction Nazca Plate Under S American Plate Andes Mountains Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings http://pubs.usgs.gov/gip/dynamic/Nazca.html Conclusion • The biogeochemical cycles, the rock cycle, and plate tectonics lay the groundwork for spreading life across Earth • Understanding biogeochemical cycles is crucial - Humans are causing significant changes in the ways those cycles function • Thinking in terms of systems can teach us how to avoid disrupting Earth’s processes and how to mitigate any disruptions we cause Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Conclusion • The biogeochemical cycles, the rock cycle, and plate tectonics lay the groundwork for spreading life across Earth • Understanding biogeochemical cycles is crucial - Humans are causing significant changes in the ways those cycles function • Thinking in terms of systems can teach us how to avoid disrupting Earth’s processes and how to mitigate any disruptions we cause Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Conclusion • The biogeochemical cycles, the rock cycle, and plate tectonics lay the groundwork for spreading life across Earth • Understanding biogeochemical cycles is crucial - Humans are causing significant changes in the ways those cycles function • Thinking in terms of systems can teach us how to avoid disrupting Earth’s processes and how to mitigate any disruptions we cause Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review The term “system” includes all of the following, except: a) A network of relationships among various components b) The various components tend to minimize interactions c) Energy, matter, and information are exchanged between components d) Energy and matter are valuable inputs to the system Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Which of the following describes a positive feedback loop? a) It drives a system towards an extreme b) It stabilizes the system c) It causes the system to move in opposite directions at the same rates d) It causes the system to maintain a constant condition Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Which of the following is a correct statement? a) b) c) d) Energy and matter flow in one direction only Energy and matter both cycle repeatedly Energy flows in one direction, while matter recycles Matter flows in one direction, while energy recycles Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review What is the definition of “net primary production”? a) Assimilation of energy by heterotrophs b) Elements and compounds that are required for survival c) Energy remaining after respiration that is used to generate biomass d) Assimilation of energy by autotrophs Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Which biogeochemical cycle comprises 78% of our atmosphere, and is contained in proteins, DNA and RNA? a) b) c) d) Carbon Nitrogen Water Phosphorus Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Which biogeochemical cycle is being affected by damming rivers, and altering the surface and vegetation? a) b) c) d) Carbon Nitrogen Water Phosphorus Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Review Which rock is formed from magma; for example, granite and basalt? a) b) c) d) Sedimentary Igneous Metamorphic Phosphorus Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Weighing the Issues Who should pay for cleanup of the nitrate entering the Gulf of Mexico? a) b) c) d) The federal government State governments Fishermen Farmers responsible for fertilizer runoff Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings QUESTION: Interpreting Graphs and Data According to this graph, which ecosystem has the warmest temperature and most rainfall? Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings a) Temperate grassland b) Boreal forest c) Savannah d) Tropical rain forest QUESTION: Interpreting Graphs and Data What would be created as a result of this figure? a) An earthquake-prone area b) A slip-strike fault c) Colliding plates d) New crust Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings