Lecture Outlines Chapter 5 Environment: The Science behind the Stories 4th Edition

1. Lecture Outlines Chapter 5 Environment:The Science behind the Stories 4th Edition Withgott/Brennan

2. Notes HW • Write each slide title on the left side of the paper • Summarize provided information on the right side of the paper • If there are slides with Objectives or “this lecture will help you understand” you do NOT need to write these. • Define any words or answer any questions or fill in the blanks when something appears in red. • Sometimes it is a question linked to a website you should view • Sometime there are comments written in purple. You do not need to write these. They are just my personal commentary  • Be prepared to answer questions at the end.

3. This lecture will help you understand: Environmental systems Ecosystems and their services How living and nonliving entities interact Landscape ecology, GIS and ecological modeling The water, carbon, nitrogen, and phosphorus cycles Human impacts on these cycles

4. Central Case: The Gulf of Mexico’s “Dead Zone” The Gulf of Mexico brings in a billion pounds/year of shrimp, fish, and shellfish Gulf “dead zone” = a region of water so depleted of oxygen That marine organisms are killed or driven away Hypoxia ? From fertilizer, fossil fuel emissions, runoff, sewage Above: algae bloom in Gulf of Mexico. Left: magnified example of one type of algae.

5. Systems show several defining properties System = a network of relationships among parts, elements, or components They interact with and influence one another They exchange energy, matter, or information Systems receive inputs of energy, matter, or information Feedback loop ? Negative and positive feedback loops DO NOT mean bad or good

6. Negative feedback loop Negative feedback loop = output from a system moving in one direction acts as input That moves the system in the other direction Input and output neutralize one another Stabilizes the system Example: predator – prey interactions Most common in nature Give 2 additional examples?

7. Positive feedback loop Positive feedback loop = instead of stabilizing a system, it drives it further toward one extreme or another Exponential growth in human population, erosion, melting sea ice Give 2 additional examples? Rare in nature But is common in natural systems altered by humans

8. Systems are active Dynamic equilibrium = system processes move in opposing directions Balancing their effects Homeostasis ? Give 2 additional examples?

9. Eutrophication The process of nutrient over-enrichment leads to: Blooms of algae Increased production of organic matter Decomposition and hypoxia

10. Eutrophication-Write & MEMORIZE THESE STEPS!!!! Algae dies and is eaten by aerobic bacteria • Nutrients enter the water: Generally fertilizer, sewage, animal waste & detergents (nitrates & phosphates) NOT pesticides • Excess algae grows • blocks out sun for SAV • SAV dies & no longer releases DO • Bacteria grows exponentially using all the dissolved oxygen • Hypoxic zone develops and fish and benthic organisms die due to lack of oxygen

11. Systems are perceived in various ways Earth consists of structural spheres Lithosphere ? Atmosphere ? Hydrosphere ? Biosphere ?

12. Ecosystems Ecosystem = all organisms biotic ? and abiotic ? entities that occur and interact in a particular area at the same time Biological entities are tightly intertwined with chemical and physical entities Through interactions and feedback loops

13. Energy is converted to biomass Primary production = conversion ofsolar energy to chemical energy in sugars by autotrophs Gross primary production (GPP) ? Net primary production(NPP) ? Available for consumption by heterotrophs Productivity ?

14. Net primary productivity of ecosystems High net primary productivity = ecosystems whose plants rapidly convert solar energy to biomass List the terrestrial & aquatic ecosystems with the greatest & smallest primary productivity?

15. NPP variation causes global geographic patterns NPP increases with temperature and precipitation in __?___ ecosystems, and with light and nutrients in __?____ ecosystems

16. Nutrients can limit productivity Nutrients ? Macronutrients = required in __?___ amounts Nitrogen, carbon, phosphorus Micronutrients = nutrients needed in __?____ amounts Nutrients stimulate plant production Nitrogen and phosphorus are important for plant andalgal growth

17. Worldwide marine dead zones Over 400 dead zones occur globally Most are off the coasts of Europe and the U.S. Mostly due to farm, city and industrial pollution Some are seasonal, others are permanent Fisheries and ecosystems are devastated Causing over $2 billion/year in lost harvests

18. Ecosystems interact spatially Adjacent ecosystems may share components and interact I.e. prairie and forests interact where they converge Ecotones ? Elements of each ecosystem mix

19. Metapopulations and conservation biology Metapopulation ? Most members stay within patches Some individuals may move among patches or mate with those of other patches Individuals in small, isolated patches risk extinction Conservation biologists ? Human development fragments habitat Creating small, isolated patches Habitat corridors that link patches protect biodiversity

20. Remote sensing applies landscape ecology Remote sensing allows scientists to take a landscape perspective Geographic information system (GIS) ?

21. Ecosystems provide vital services Human society depends on healthy, functioning ecosystems Ecosystem services ? List 5 examples?

22. Nutrients continually circulate Nutrient (biogeochemical) cycles = the movement of nutrients through ecosystems Atmosphere, hydrosphere, lithosphere, and biosphere Pools(reservoirs) = where nutrients reside for varying amounts of time (the residence time) Flux ? Can change over time Is influenced by human activities

23. Main components of a biogeochemical cycle Source = a pool that releases less/more (circle one)? nutrients than it accepts Sinks = a pool that accepts less/more (circle one)? nutrients than it releases

24. The hydrologic cycle Water is essential for biochemical reactions It 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 ? Transpiration ? Precipitation, runoff, and surface water ?

25. Groundwater Aquifers ? Groundwater ? Water table ? Water may be ancient (thousands of years old)

26. Human impacts on the hydrologic cycle Removing forests and vegetation increases runoff and erosion, reduces transpiration and lowers water tables Irrigating agricultural fields depletes rivers, lakes and streams and increases evaporation Damming rivers increases evaporation and infiltration Emitting pollutants changes the nature of precipitation The most threatening impact: overdrawing groundwater for drinking, irrigation, and industrial use Water shortages create worldwide conflicts

27. The carbon cycle Carbon is found in carbohydrates, fats, proteins, bones, cartilage and shells Carbon cycle = describes the route of carbon atoms through the environment Photosynthesis by plants, algae and cyanobacteria Removes carbon dioxide from air and water Produces oxygen and carbohydrates Plants are a major reservoir of carbon Respiration returns carbon to the air and oceans Plants, consumers and decomposers

28. Sediment storage of carbon Decomposition returns carbon to the sediment The largest reservoir of carbon Aquatic organisms die and settle in the sediment Older layers are buried deeply and undergo high pressure, may be converted into fossil fuels Oceans are the SECONDlargest reservoir of carbon

29. Humans affect the carbon cycle Burning fossil fuels moves carbon from the ground to the air increasing NET atmospheric carbon Cutting forests and burning fields moves carbon from vegetation to the air Today’s atmospheric carbon dioxide reservoir is the largest in the past 800,000 years It is the driving force behind climate change The missing carbon sink: 1-2 billion metric tons of carbon are unaccounted for It may be taken up by plants or soils of northern temperate and boreal forests

30. The nitrogen cycle Nitrogen comprises 78% of our atmosphere It is contained in proteins, DNA and RNA Nitrogen cycle = describes the routes that nitrogen atoms take through the environment Nitrogen gas cannot be used by organisms Nitrogen fixation = lightning or nitrogen-fixing bacteria combine (fix) nitrogen with hydrogen To form ammonium Which can be used by some plants

31. Nitrification and denitrification Nitrification = bacteria convert ammonium ions first into nitrite (NO2-) ions then into nitrate (most common) (NO3-) ions Plants can take up these ions Animals obtain nitrogen by eating plants or other animals Decomposers get it from dead and decaying plants or other animals Releasing ammonium ions to nitrifying bacteria Denitrifying bacteria = convert nitrates in soil or water to gaseous nitrogen N2 Releasing it back into the atmosphere

32. Humans affect the nitrogen cycle Haber-Bosch process ? Fixing atmospheric nitrogen with fertilizers Increases emissions of greenhouse gases and smog Washes calcium and potassium out of soil Acidifies water and soils Moves nitrogen into terrestrial systems and oceans Reduces diversity of plants adapted to low-nitrogen soils Changed estuaries and coastal ecosystems and fisheries

33. Humans put nitrogen into the environment Fully half of nitrogen entering the environment is of human origin

34. The phosphorus cycle Phosphorus (P) is a key component of cell membranes, DNA, RNA, ATP and ADP Phosphorus cycle = describes the routes that phosphorus atoms take through the environment Most phosphorus is within rocks It is released by weathering There is no significant atmospheric component With naturally low environmental concentrations Phosphorus is a limiting factor for plant growth

35. 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 Produces murkier waters Alters the structure and function of aquatic systems Do not buy detergents that contain phosphate

36. Solutions to the dead zone The Harmful Algal Bloom and Hypoxia Research and Control Act (1998) Called for an assessment of hypoxia in the dead zone Solutions outlined included: Reduce nitrogen fertilizer use in Midwestern farms Apply fertilizer at times which minimize runoff Use alternative crops and manage manure better Restore wetlands and create artificial ones Improve sewage treatment technologies Evaluate these approaches

37. Decreasing pollution Scientists, farmers and policymakers are encouraged to Decrease fertilizer use While safeguarding agriculture Offering insurance and incentives Using new farming methods Planting cover crops Maintaining wetlands There have been some successes Despite a lack of funding

38. 5-A • Explain the difference between a positive and negative feedback loop. Which one is more common in nature? • Describe how hypoxic conditions occur in the Gulf of Mexico. • Explain the difference between gross primary productivity and net primary productivity. • Define ecotone. How do ecotones affect communities?

39. 5-B • Define ecosystem service? Give five examples. • For biogeochemical cycles, define the following: pool, flux, source, sink, & residence time. • What is the difference between an aquifer, groundwater, and the water table? • What is the Haber-Bosch process and how did it change humanity?

40. 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.

41. 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.

42. 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.

43. 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.

44. 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.

45. 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.

46. 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

47. 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

48. QUESTION: Review Which biogeochemical cycle comprises 78% of our atmosphere; and is contained in proteins, DNA, and RNA? • Carbon • Nitrogen • Water • Phosphorus

49. QUESTION: Review Which biogeochemical cycle comprises 78% of our atmosphere; and is contained in proteins, DNA, and RNA? • Carbon • Nitrogen • Water • Phosphorus

50. QUESTION: Review Which biogeochemical cycle is being affected by damming rivers, and by altering the surface and vegetation? • Carbon • Nitrogen • Hydrologic • Phosphorus