1. Ecosystems Chapter 54

2. Overview Food Chains and Food Webs Productivity Ecological Pyramids Biomagnification Nutrient Cycles Global Warming

3. Ecosystems -The Community along with: Nutrient CyclingEnergy Flow

4. Energy Transfer in Ecosystems Food / Energy Pyramid Primary Consumers eat producers, incorporating the energy into the next level. Only 10 % of energy consumed moves to next level Animals loose 90% of the energy at each level Why are Big Fierce Animals so Rare?? Consumers are Heterotrophs Limited by Thermodynamcis

5. Simple Food Chains Trophic Levels Both Marine and Terrestrial

6. Productivity What is it? Season effects varies by ecosystem

7. Productivity –Amount of food in an ecosystem Primary productivity is growth of producers (Biomass) the baseline for the entire ecosystem. Gross productivity is the total amount of food produced or ingested at that trophic level. Net productivity is amount available to next trophic level, after respiration Measured by dry weight or calories

8. Productivity rates: Kelp beds have highest productivity Tropical rainforest highest per sq. meter on land, but only covers 3.3 % of globe Open ocean, one of the lowest, but because it covers 65.0 % it equals rainforest Marsh lands nearly equal tropical rainforest productivity

11. Summary of satellite data on global primary productivity from 1997 to August 2000

12. NORTH AMERICA ATLANTIC OCEAN AFRICA SPAIN Winter Spring

13. Ocean Currents

14. Wind from the north starts surface ocean water moving Earth's rotational force deflects moving water westward c. Deep, cold water moves up to replace water moving west Upwelling

15. Fig. 55-7 Atlantic Ocean Moriches Bay Shinnecock Bay Long Island Great South Bay A B C D E F G EXPERIMENT Ammonium enriched Phosphate enriched Unenriched control RESULTS A BC D E F G 30 24 18 12 6 0 Collection site Phytoplankton density (millions of cells per mL)

16. Table 55-1

18. Food Webs Energy transfer follows trophic levels Many animals eat at several trophic levels Omnivores: like most of us At salad bar you’re a herbivore Eating a burger makes you a carnivore

19. marsh hawk crow upland sandpiper garter snake frog spider weaselbadgercoyote ground squirrelpocket gopherprairie vole sparrow earthworms, insects First Trophic Level Second Trophic Level Higher Trophic Levels Sampling of connections in a Tall grass prairie food web grasses, composites

20. Energy Transfer in Ecosystems Food / Energy Pyramid Only 10 % of energy consumed moves to next level Why are Big Fierce Animals so Rare?? Consumers are Heterotrophs Limited by Thermodynamics

21. Laws of Thermodynamics Energy = ability to do work 1 st Law = Total amount of energy is a constant 2 nd Law = Some energy is lost in every transfer, not 100% efficient Most energy lost as heat Autotrophs about 1% efficient (light–sugar) Heterotrophs about 10% efficient

23. Energy Pyramid

24. Pyramid of Numbers

25. Nutrients Cycle Elements change form, but are not lost No more carbon now than when the dinosaurs lived !! May be trapped in bio-inactive forms Ice, fossil fuels Held together in chemical bonds Breaking bonds – releases energy Uses energy to form bonds

26. Cycles:

27. Nutrient cycles to learn: Water Carbon Nitrogen

29. Carbon Cycle Large reservoirs in rocks (99%), fossil fuels Associated with Greenhouse Effect Build up of CO 2, CH 4 etc. in atmosphere Raise sea levels – flooding islands, coasts More severe weather ?? Food chain moves through Carbon cycle

31. Nitrogen Cycle Largest pool is in atmosphere (80%) a generally bio-inactive form Nitrogen fixing bacteria capture it from air Many native plants have nitrogen fixing root nodules After water the most growth-limiting nutrient Nitrogen important for Autotrophs to make protein Protein breakdown releases it back to environment in urine

33. Nitrogen Cycle Always need to replenish agriculture fields with fertilizer. Denitrifying bacteria release it back to atmosphere Tightly cycled in Ecosystems Needed to make amino acids

34. Nitrogen Metabolism In amino acids, nucleotides Nitrogen fixing bacteria (N 2 ->NH 3 ) In soil, and some plant root nodules Nitrifying bacteria convert NH 3 -> NO 2 In soil, or biotower in treatment plant Denitrifying bacteria N0 2 -(Nitrite) or N0 3 (Nitrate) to atmospheric N 2 In soil, counter-act fertilizers

35. Forests and Nitrogen Cycle Most of nitrogen tied up in a tree’s Biomass Soils tend to be nutrient poor Often highest in later stages of succession Burning trees releases nutrients Soil fertility only lasts a few seasons Nitrogen is leached out with rains Classic problem with Slash and Burn

37. Fig. 31.8

38. Hubbard Brook

39. Loss of Nitrate from a forest after clear cutting

40. 1620 1850 1850 (pocket only) 1990 Extent of deforestation in the United States Remaining virgin forest

41. Bioaccumulation & Biomagnification Bioaccumulation Build-up of substance within body Lead in humans Calcium from milk to already strong bones Biomagnification build up of of substance along food chain DDT and birds Rachel Carlson’s Silent Spring

42. Build up of DDT along Food Chain Bioaccumulation Biomagnification

43. Fig. 34.1

44. Peregrine falcon

45. DDT Residues (ppm wet weight of whole live organism) Ring-billed gull fledgling (Larus delawarensis) Herring gull (Larus argentatus) Osprey (Pandion haliaetus) Green heron (Butorides virescens) Atlantic needlefish (Strongylira marina) Summer flounder (Paralychthys dentatus) Sheepshead minnow (Cyprinodon variegatus) Hard clam (Mercenaria mercenaria) Marsh grass shoots (Spartina patens) Flying insects (mostly flies) Mud snail (Nassarius obsoletus) Shrimps (composite of several samples) Green alga (Cladophora gracilis) Plankton (mostly zooplankton) Water 75.5 18.5 13.8 3.57 2.07 1.28 0.94 0.42 0.33 0.30 0.26 0.16 0.083 0.040 0.00005 Data for a Long Island, NY estuary in 1967

46. Greenhouse Effect Gasses trap heat in atmosphere Carbon dioxide, methane, CFC’s Anthropogenic use of these gasses is increasing Earth’s temperature appears to be warming Hard to measure a world temperature

47. Sun’s rays penetrate atmosphere. Enters as light not as heat. Hitting the earth, light changes to heat. Surface radiates heat. Greenhouse gases absorb some heat and radiate it back toward Earth. Increased greenhouse gases trap more heat near Earth’s surface. Greenhouse Effect

48. Correlation in changes in atmospheric CO 2 with ice ages and interglacials

49. Fig. 55-21 CO 2 CO 2 concentration (ppm) Temperature 1960 300 Average global temperature (ºC) 1965197019751980 Year 19851990199520002005 13.6 13.7 13.8 13.9 14.0 14.1 14.2 14.3 14.4 14.5 14.6 14.7 14.8 14.9 310 320 330 340 350 360 370 380 390

50. Satellite image of an iceberg roughly the same size as Connecticut Antarctica 2000

52. National Snow and Ice Data Center

55. Fig. 34.6

56. Fig. 55-24 O2O2 Sunlight Cl 2 O 2 Chlorine Chlorine atom O3O3 O2O2 ClO

57. Fig. 55-24 O2O2 Sunlight Cl 2 O 2 Chlorine Chlorine atom O3O3 O2O2 ClO

58. “Tragedy of the Commons”