1. Today -Review exam (briefly) -Biodiversity - Ecosystems -Nutrients as Pollutants - Introduce last class Activity (In-class Debate) Next Tuesday - Quiz - More Atmospheric Pollutants - Begin Water Pollution

2. Biodiversity – diversity of life - Variety of genes among individuals of a species –color, height - Variety of Species - Variety of ecosystems –coral reefs, rainforests

3. Ecosystems an assemblage of different species and their physical environment, all organized in a way that each population of organisms obtains energy and nutrients through specific pathways within the ecosystem.

5. Ecosystem components Functional groups of organisms a. Producers (autotrophs)fix energy and inorganic nutrients into organic forms that are accessible to other organisms. b. Consumers (heterotrophs) get energy and nutrients by consuming the producers. Decomposers (heterotrophs) get energy and nutrients by decomposing all other organisms that have died. Physical or Abiotic Environment Land Water Air

6. Energy transfer Unidirectional transfer of energy from one functional group to another until it is dissipated from the ecosystem as heat Energy is transferred in one direction, from producers to consumers to decomposers. After decomposers have extracted energy from dead organic matter, the energy is no longer available within the ecosystem.

7. Fig: ecosystem

8. Nutrient and material cycling Cycling of nutrients among the various groups of organisms through trophic (feeding) interactions Unlike energy, nutrients do not move unidirectionally through the ecosystem. They are recycled through the activity of decomposers, which return the organic nutrients to their inorganic forms. This process is called mineralization. The mineral nutrients are then available again to producers and microbes that can use them.

10. slide/ sea urchin

11. slide/ otter in kelp bed

12. fig/ otter,urc hin, kelp circle otters eat sea urchins eat kelp kelp provides habitat for otter

13. As we discussed Tuesday, Phosphorus Is very often limiting in freshwater systems What is happening here? Why doesn’t the line keep Going up?

14. Multiple or co-limiting factors – often it is more Complex than Liebig’s Law of the minimum Look what happens with the addition of N

15. Increase in autotrophs...

16. Decrease in autotrophs... Primary productivity is an important control on ecosystem productivity and one reason why we focus so much on nutrients

17. INPUTS Weathering Atmospheric Input Biological Nitrogen Fixation Immigration OUTPUTS Erosion Leaching Gaseous Losses Emigration/Harvesting Nutrient flux in Ecosystems

18. Excess Nitrogen – Too much of a good thing! Because Nitrogen often limits plant growth humans have gone to great lengths to use it as fertilizer It is also a by product of all types of combustion The net result is that we have altered the natural way that Nitrogen cycles more than we have any other element -including Carbon

19. In an undisturbed nitrogen cycle the element cycles very Efficiently – it is valuable so not readily given up by biota

20. In an undisturbed nitrogen cycle the element cycles very Efficiently – it is valuable so not readily given up by biota But humans add HUGE amounts of Nitrogen to the ecosystem 160

21. Nitrogen containing Compounds N 2 – nitrogen gas NO 3 – nitrate NO 2 - nitrite NH 4 – ammonium NH 3 – ammonia N 2 O – Nitrous Oxide Organic Nitrogen – Living and dead plants And animals

22. Human Emissions - Combustion NO x N 2 +O 2 --> 2NO Forms in high temperatures of combustion engine Converted in the atmosphere to HNO 3 - nitric acid From atm.

23. Human Emissions - Fertilizer N 2 +Energy H + --> NH 3 Formed by the Haber process Added to fields all over the world, but often lost after harvest

24. Nitrogen from agriculture and from combustion isn’t coupled in A tightly cycling system and often “escapes” into the atmosphere Forming acid precipitation

25. “Natural Rain” Pure water –pH of 7 - neutral Rain is not pure water –Dissolved CO 2 –Forms carbonic acid pH = 5.7 Other dissolved substances

26. Human Influence Increasing emissions of NO x 55% of NO x emissions are human related Regionally these percentages can be much higher –NE US - 65%, Europe - 80%

27. WHY is acid rain a threat? I Because acid rain will cause more cases of respiratory disease, skin irritation and eye irritation. People from the Kanto Plains of Japan have experienced severe eye and skin irritation since 1970. Because acid rain reduces crop productivity. In the Netherlands, damage to crops is estimated at $182 million a year. In Japan, damage to vegetable crops has been reported. Because acid rain corrodes and destroys buildings and monuments. The EPA estimates that annual costs of repairing damage due to acid rain exceeds $5 billion. Marble is particularly vulnerable.

28. WHY is acid rain a threat? II Because acid rain damages plant and animal life in lakes and streams. Lakes die, rendering them unable to support life. In Maine, 2% of trout habitats and 6% of minnow habitats are no longer able to support animal life. More than 1/2 of lakes currently being studied in Canada have lost 40-50% of species such as mollusks and insects. Florida has the highest percentage of acidic surface waters - 23% of lakes and 39% of streams.

29. WHY is acid rain a threat? III Because acid rain harms forests. Over 20-25% of European forests are classified as moderately or severely damaged. In France, 10-20% of trees in sensitive regions have lost more than 25% of their foliage. Because acid rain degrades soils. In Sweden soils have become up to thirty times more acidic in the last sixty years, and the acid deposition extends several meters below soil surface.

32. What happens to the rain when it hit the ground? Acid in rain …. … will react with a base in soil Many of our mobile ions produced in chemical weathering can “neutralize” the acid Base Cations: Ca, Mg, Na, K What determines the neutralization capacity of soil?

35. Acid Rain Reactions to convert to acid take place in ~2 days - travel 1000 miles Down wind - Acid rain Dry Dep. vs Wet Dep. Dry Deposition –50 % of total –Can react with plants - strip nutrients –Tree dieback

36. pH of Rain - Eastern US pH of rain over the Northeast averages in around 4.5 Note that in the early years the range is expanding 1990 things are getting better...

37. pH Rain - Europe Europe experiences similar acid rain Coal burning in England and Germany

38. Emissions vs. Effects All areas receiving acid deposition are not susceptible to the effects of the rain….why?

39. Acid Rain and Trees

40. Forests affected by Acid Rain Northeast US Canada Northern Europe Asia

41. Acid Rain and Buildings Many buildings are made of concrete and or stone These compounds act as bases and react with acid The building technically “weathers” very fast, or Non technically “crumbles”

42. Europe The US Capitol

43. When the pH drops below 6.0 species start to die off. When one species dies, others that depend on it may as well Acid Rain Effects – Aquatic Systems

44. Acid Neutralization How does this work? Cation Exchange on clay minerals Role of chemical weathering...

45. How does acid kill the fish? One way is mobilizing metals When all base cations are striped from soils Acid now reacts with metals e.g. aluminum –Normally aluminum is immobile –below pH 5 - mobile aluminum Fish breath in the water –Aluminum comes out of solution –Clogs gills - suffocate

46. Where do N emissions originate? ~ 55% come from agriculture ~ 25% come from industry – e.g. coal fired power plants ~ 20% come from automobiles

47. Major powerplants – sources of N emissions – Acid rain

48. Change in NOx emissions 1990 - 1999

49. Nitrogen deposition 1989 - 1991Nitrogen deposition 1995 - 1998

50. Surface water sensitivity to Acid Deposition - known in 1990

51. Surface water sensitivity to Acid Deposition - known in 1998

52. Watersheds – Large areas thought to be nitrogen saturated

53. Land - Sensitive Ecosystems to Nitrogen Deposition

54. Change in NOx emissions 1990 - 1999

55. 1990 5,700 1998 11,600 Emissions increasing in the western US

56. 1990 15,800 1998 17,600 Emissions increasing in the western US

57. 1990 24,700 1998 28,800 Emissions increasing in the western US

58. Recent and current policies to reduce acid precipitation and Nitrogen emissions are shifting the problem from one area To another While emissions are remaining stable or decreasing in already Heavily impacted areas, they are increasing in formerly “clean” or relatively unimpacted areas -Especially including other countries! -Nitrogen is only one compound important in acid rain and pollutant emissions to the atmosphere sulfur – SOx – has been a relative success story mercury is not an acid forming element, but is extremely toxic and is still increasing

59. Acid Rain Summary

60. http://www.epa.gov/airmarkets/picturethis/index.htm http://www.epa.gov/castnet/charts.html For more information see

64. Acid Rain Effects Other animals suceptible