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Chapter 5: Earth Systems and Ecosystem Ecology

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1 Chapter 5: Earth Systems and Ecosystem Ecology
GEOG 101 – Days 2 & 3 Chapter 5: Earth Systems and Ecosystem Ecology Source:

2 Housekeeping Items Last class we looked at the scope of the course and what you need to know to be in it (i.e. assignments, web site, etc.), and we started in on Chapter 1. We got almost all the way through, so please look at the notes on the web and read the rest of the chapter on your own. Does anyone need a course outline? There are still, so far as I know, textbooks in the bookstore. I will pass around the sign-in sheet for anyone not here last time, and also a folder of possibly interesting articles.

3 Housekeeping Items Wednesday is the end of the formal waitlist period. I will see who’s at the top of list at that time and probably add two additional people to the course. I try to answer s promptly, but my laptop over the holidays and I haven’t been able to replace it yet, and I have limited access to e- mail over the weekend. So, BE PATIENT! Today we will start to cover Chapter 5. We will come back to the very important topic of biodiversity (addressed in Chapters 3 and 4) later in the semester. Please read the textbook yourself. There is way more in there than we can cover in class!

4 This lecture on Chapter 5 will help you understand: (as mentioned last week, we are
skipping Chapters 2-4)‏ The nature of environmental systems How plate tectonics and the rock cycle shape the Earth [we will only touch on this lightly] Ecosystems and how living and nonliving entities interact Landscape ecology The water, carbon, nitrogen, and phosphorus cycles 5-4

5 But first some housekeeping items...
Decide soon if you are going to drop the course as we have quite a few people on the waiting list. How many people have seen The 11th Hour or The Human Footprint? Before we move on, I would like to read you something from Paul Hawken.... (http://globalmindshift.wordpress.com/2 009/05/21/the-unforgettable- commencement-address-by-paul- hawken-to-the-class-of-2009-university- of-portland-may /).

6 Central Case: The Plight of the St. Lawrence Belugas
Decreasing population due to GI cancer from pollutants (PAHs from fossil fuels)‏ Biomagnification of contaminants through food chain PAHs come from as far away as the Golden Horseshoe in Ontario Agricultural development also leads to hypoxia and eutrophication Beluga is “vulnerable” and is an indicator of the Great Lakes – St. Lawrence ecosystem image source: Aqua Views 5-6

7 Systems show several defining properties
System = a network of relationships among parts 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 hard to understand and predict Feedback loop = a system’s output serves as input to that same system 5-7

8 Negative feedback loop
Negative feedback loop = output that results from a system moving in one direction acts as input that moves the system in the other direction. FIGURE 5.1 5-8

9 Positive feedback loop
Positive feedback loop = instead of stabilizing a system, it drives it further toward one extreme or another FIGURE 5.1 5-9

10 Systems show several defining properties
Dynamic equilibrium = system processes move in opposing directions at equivalent rates, balancing their effects Homeostasis = a system maintains constant or stable internal conditions Emergent properties = system characteristics not evident in the components alone “The whole is more than the sum of the parts” FIGURE 5.2 5-10

11 A systems approach 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 5-11

12 Complex systems and subsystems: watershed
5-12

13 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 5-13

14 The rock cycle Since this topic is covered extensively in GEOG 212, I will mostly skip over it. 5-14 14 14

15 Rocks help determine soil chemistry, which influences ecosystems
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 5-15 15 15

16 Magma = the molten, liquid state of rock
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)‏ 5-16 16 16

17 Sedimentary rock 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 5-17 17 17

18 Metamorphic rock 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 5-18 18 18

19 Plate tectonics shapes Earth’s geography
Plate tectonics = process that underlies earthquakes and volcanoes and that determines the geography of the Earth’s surface Crust = lightweight thin component of Earth’s surface Mantle = malleable layer on which the crust floats Core = molten heavy center of Earth made mostly of iron 5-19 19 19

20 The Earth has 15 major tectonic plates
Movement of these plates influences climate and evolution FIGURE 5.6 5-20

21 Plate boundaries 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 FIGURE 5.7 5-21

22 Tectonic plates can collide
Convergent plate boundaries = where plates collide Subduction = one plate of crust may slide beneath another Uplift = lift material from both plates FIGURE 5.7 5-22 22 22

23 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 5-23 23 23

24 Ecosystems are systems of interacting living and nonliving entities
Energy entering the system is processed and transformed Matter is recycled within ecosystem, resulting in outputs such as heat, water flow, and waste products FIGURE 5.8 5-24 24 24

25 Energy is converted to biomass
Primary production = conversion of solar energy to chemical energy by autotrophs Gross primary production (GPP) = assimilation of energy by autotrophs Net primary production (NPP) = energy remaining after respiration, and is used to generate biomass Available for heterotrophs Secondary production = biomass generated by heterotrophs Productivity = rate at which ecosystems generate biomass 5-25 25 25

26 Net primary productivity
High net primary productivity = ecosystems whose plants rapidly convert solar energy to biomass FIGURE 5.9 5-26

27 Dramatic growth of algae in water treated with phosphate
Nutrients can limit productivity Nutrients = elements and compounds required for survival that are consumed by organisms Macronutrients = nutrients required in relative large amounts (Nitrogen, carbon, phosphorus) Micronutrients = nutrients needed in smaller amounts FIGURE 5.10 Dramatic growth of algae in water treated with phosphate 5-27 27 27

28 Nutrient runoff is devastating aquatic systems
FIGURE 5.11 5-28

29 Ecosystems are integrated spatially
Ecosystems vary greatly in size The term “ecosystem” is most often applied to self-contained systems of moderate geographic extent Adjacent ecosystems may share components and interact Ecotones = transitional zones between two ecosystems in which elements of different ecosystems mix 5-29 29 29

30 Landscape ecologists study geographic areas with multiple ecosystems
Patches = form the landscape, and are distributed spatially in complex patterns (a mosaic)‏ Landscape = larger than an ecosystem and smaller than a biome FIGURE 5.12 5-30 30 30

31 Populations and Biodiversity
Metapopulation = a network of subpopulations Most members of species stay within patches but may move among patches or mate with those of other patches Individuals in small patches risk extinction Conservation biology = study the loss, protection, and restoration of biodiversity. Considers cores and corridors, and has been influenced by island biogeography, which is the study of the relative abundance of species and sizes of populations on islands depending on their size and distance from the mainland. 5-31

32 Remote sensing helps us applies landscape ecology
Remote sensing technologies allow scientists to create a complete picture of the landscape Geographic information systems (GIS) = computer software used in landscape ecology research Can analyze how elements within the landscape are arranged to help make planning and land-use decisions Here’s an interesting example from a different discipline: yaegwuekwe/multimediafinal.html FIGURE 5.13 5-32 32 32

33 Nutrients circulate via biogeochemical cycles (more on this soon)‏
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 5-33 33 33

34 The hydrological cycle
FIGURE 5.15 5-34

35 The hydrological cycle influences all other cycles
Water is essential for biochemical reactions and is involved in nearly every environmental system 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 Run-off= movement of water across the land into receiving water bodies Infiltration= seeping of water into underground aquifers 5-35

36 Groundwater Aquifers = underground reservoirs of sponge- like regions of rock and soil that hold groundwater 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 5-36

37 Human impacts on hydrological 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 The most threatening impact is overdrawing groundwater for drinking, irrigation, and industrial use 5-37 37 37

38 weighing the issues Your water Are you aware of any water shortages or conflicts over water use in your region? What is the quality of your water, and what pollution threats does it face? Given your knowledge of the hydrological cycle, what solutions would you propose for water problems in your region? 4-38

39 The carbon cycle FIGURE 5.16 5-39

40 The carbon cycle Carbon is found in carbohydrates, fats, proteins, bones 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 The world’s oceans are the second largest reservoir of carbon 5-40 40 40

41 Humans affect the carbon cycle
Burning fossil fuels moves carbon from the ground to the air Cutting forests and burning fields moves carbon from organisms 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 5-41

42 The nitrogen cycle FIGURE 5.17 5-42

43 The nitrogen cycle Nitrogen is 78% of our atmosphere but N2 gas is inert (not a usable form)‏ Nitrogen fixation = Nitrogen gas is fixed (made into ammonia) by nitrogen-fixing bacteria Usable form (ammonium ions)‏ FIGURE 5.18 5-43

44 Nitrification and denitrification
Nitrification = bacteria that convert ammonium ions first into nitrite ions then into nitrate ions Plants can take up these ions Animals obtain nitrogen by eating plants or other animals Denitrifying bacteria = convert nitrates in soil or water to gaseous nitrogen, releasing it back into the atmosphere 5-44

45 Humans affect the nitrogen cycle
Haber-Bosch process = synthetic production of fertilizers by combining nitrogen and hydrogen to synthesize ammonia 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 Increased transfer from rivers to oceans Reduced biodiversity of plants adapted to low-nitrogen soils Changed estuaries and coastal ecosystems and fisheries 5-45

46 Eutrophication The process of nutrient over-enrichment, blooms of algae, increased production of organic matter, and ecosystem degradation FIGURE 5.19 5-46

47 The phosphorus cycle FIGURE 5.20 5-47

48 The phosphorus cycle involves mainly lithosphere and ocean
Phosphorus is a key component of cell membranes, DNA, RNA, ATP and ADP Geology: Most phosphorus is within rocks and is released by weathering With naturally low environmental concentrations, phosphorus is a limiting factor for plant growth Plants take up phosphorus when it is dissolved in water 5-48

49 We 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 Household detergents may contain phosphorus 5-49

50 Conclusion The hydrologic cycle, the rock cycle, and plate tectonics lay the groundwork for spreading life across Earth Understanding biogeochemical cycles is crucial because humans change the way 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 We can learn about sustainability from natural systems 5-50 50 50

51 QUESTION: Review The term “system” includes all of the following, except: A network of relationships among various components The various components tend to minimize interactions Energy, matter, and information are exchanged between components Energy and matter are valuable inputs to the system Answer: b 5-51 51

52 QUESTION: Review Which of the following describes a positive feedback loop? It drives a system towards an extreme It stabilizes the system It causes the system to move in opposite directions at the same rates It causes the system to maintain a constant condition Answer: a 5-52 52

53 QUESTION: Review Which of the following is a correct statement?
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 Answer: c 5-53 53

54 QUESTION: Review What is the definition of “net primary production”?
Assimilation of energy by heterotrophs Elements and compounds that are required for survival Energy remaining after respiration that is used to generate biomass Assimilation of energy by autotrophs Answer: c 5-54 54

55 QUESTION: Review Which biogeochemical cycle is contained in proteins, DNA and RNA? Carbon Nitrogen Water Phosphorus Answer: b 5-55 55

56 QUESTION: Review Which biogeochemical cycle is being affected by damming rivers, and altering the surface and vegetation? Carbon Nitrogen Water Phosphorus Answer: b 5-56 56

57 QUESTION: Review Which rock is formed from magma; for example, granite and basalt? Sedimentary Igneous Metamorphic Phosphorus Answer: b 5-57 57

58 QUESTION: Interpreting Graphs and Data
According to this graph, which ecosystem has the warmest temperature and most rainfall? a) Temperate grassland b) Boreal forest c) Savannah d) Tropical rain forest Answer: a FIGURE 5.9 5-58 58

59 QUESTION: Interpreting Graphs and Data
What would be created as a result of this (Figure 5.7)? An earthquake-prone area A slip-strike fault Colliding plates New crust Answer: d FIGURE 5.7 5-59 59


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