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2. I watched the rest of Home and, after discussing the shrinkage of Greenland’s ice cap (25% of the world’s fresh water!), it talked about the impacts of sea level rise on cities. Then it did a brief recap of some of the main crises outlined in the film and offered brief examples of very hopeful developments in different parts of world (for instance, in Gabon, Bangladesh, and Costa Rica). Cameron very kindly looked into nanotechnology: “UCLA molecular biologist Bénédicte Trouiller found that nano-titanium dioxide -- the nanomaterial most commonly used in consumer products today -- can damage or destroy DNA and chromosomes at degrees that can be linked to ‘all the big killers of man.’ Nano-titanium dioxide is so pervasive that the Environmental Working Groupsays it has calculated that close to 10,000 over-the-counter products use it in one form or another. It's ‘in everything from medicine capsules and nutritional supplements, to food icing and additives, to skin creams, oils and toothpaste,’ Schiestl says. He adds that at least 2 million pounds of nanosized titanium dioxide are produced and used in the U.S. each year... Including in numerous children’s products.”http://www.nanotechproject.org/news/archive/8302/http://www.nanotechproject.org/process/assets/files/8278/pen_submission_cpsc.pdfhttp://www.nanotechproject.org/inventories/consumer/browse/products/fraser_rainshell/

3. Upon completing this chapter, you will be able to: • Describe the fundamental properties of environmental systems and the importance of linkages among environmental systems and processes • Define ecosystem and discuss how living and nonliving entities interact in ecosystems • Outline the fundamentals of landscape ecology, GIS, and the use of modelling in environmental science • Assess ecosystem services and their benefits to us • Summarize the main features of global water, carbon, nitrogen, and phosphorus cycles • Explain how human activity is affecting biogeochemical cycles

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5. 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 classified as “threatened” by Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and is an indicator of the Great Lakes – St. Lawrence ecosystem 3-5

6. Earth’s Environmental Systems 3-6

7. Systems are networks of relationships • System = a network of relationships among parts elements or components that interact with and influence one another • Exchange of energy, matter, or information • Open systems receive inputs of energy and matter, and produce outputs of both • Closed systems (i.e. Earth) receive input and produce outputs of energy but not matter • hard to understand and predict 3-7

8. Feedbacks are common in environmental systems • Feedback loop = a system’s output serves as input to that same system • Negative feedback loop = output that results from a system moving in one direction acts as input that moves the system in the other direction. • Positive feedback loop = instead of stabilizing a system, it drives it further toward one extreme or another • Dynamic equilibrium = system processes move in opposing directions at equivalent rates, balancing their effects 3-8

9. Negative and positive feedback loops 3-9

10. Homeostasis is a state of balance • Homeostasis = a system maintains constant or stable internal conditions • Resistance refers to the strength of the system’s tendency to remain constant • Resilience is a measure of how readily the system will return to its original state once it has been disturbed

11. A whole may be more than the sum of its parts • Emergent properties = system characteristics not evident in the components alone • “The whole is more than the sum of the parts”

12. Complex systems have multiple subsystems • 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

13. Complex systems and subsystems: watershed

14. Environmental systems may be perceived in various ways • Categorizing environmental systems helps make Earth’s dazzling complexity comprehensible • For example, the earth consists of structural spheres • Geosphere = 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

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16. Ecosystems 3-16

17. 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

18. Ecosystems are systems of interacting biotic and abiotic components Energy entering the system is processed and transformed Matter is recycled within ecosystem, resulting in outputs such as heat, water flow, and waste products

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20. Energy is converted to biomass Primary production = conversion ofsolar 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

21. High net primary productivity = ecosystems whose plants rapidly convert solar energy to biomass

22. Variation in net primary productivity among ecosystems and biomes results in geographic patterns of variation across the globe

23. Nutrient availability limits 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 Dramatic growth of algae in water treated with phosphate

24. 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

25. weighingtheissues Ecosystems Where You Live • Think about the area where you live. How would you describe the ecosystems? • How do these systems interact with one another? • If one ecosystem were greatly disturbed (say, a wetland or forest replaced by a shopping mall) what impacts might that have on the system and others nearby? 3-25

26. Patches = form the landscape, and are distributed spatially in complex patterns (a mosaic) Landscape = larger than an ecosystem and smaller than a biome Landscape ecologists study geographic patterns

27. Landscape ecologists study geographic patterns • Metapopulation = a network of subpopulations • Most members 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

28. Remote sensing and GIS are important tools Remote sensing technologies allow scientists to create a complete picture of the landscape Geographic information system (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

29. Models help scientists understand complex systems Model = a simplified representation of a complex natural process, designed to help us understand how the process occurs and to make predictions

30. What Mother Nature Does for Free

31. Ecosystem Services

32. Biogeochemical Cycles 3-32

33. Nutrients and other materials move in biogeochemical cycles 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 3-33

34. Properties of reservoirs 3-34

35. The hydrologic cycle influences all other cycles • Water is essential for biochemical reactions and is involved in nearly every environmental system • Oceans are the main reservoir (97% of water) • 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 • Infiltration= seepage into groundwater tables/ aquifers 3-35

36. The hydrologic cycle

37. The hydrologic cycle influences all other cycles (cont’d) • 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 often in the form of a spring

38. Our impacts on the hydrologic cycle are extensive 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

39. The carbon cycle circulates a vital organic nutrient • 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

40. The carbon cycle

41. The nitrogen cycle involves specialized bacteria • 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 pm the roots of certain plants (legumes) • Usable form (ammonium ions) for plants FIGURE 5.18

42. Humans affect the carbon cycle • Burning fossil fuels moves carbon from the ground to the air (from ‘source’ to ‘sink’) • 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

43. The nitrogen cycle

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

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46. We have greatly influenced 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

47. Eutrophication • The process of nutrient over-enrichment, blooms of algae, increased production of organic matter, and ecosystem degradation

48. weighingtheissues Nitrogen Pollution and Its Financial Impacts 3-48

49. The phosphorus cycle involves mainly geosphere 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 • Food webs: Plants take up phosphorus when it is dissolved in water

50. The phosphorus cycle