Ecosystems and the Physical Environment

1
Ecosystems and the Physical Environment

• Chapter 5

2
Overview

• Cycling of Materials within Ecosystems
• Nitrogen
• Phosphorus
• Carbon
• Sulfur
• Water
• Solar Radiation
• The Atmosphere
• Global Oceans
• Weather Climate
• Plate Tectonics

3
Gaia Hypothesis

• Originated by James Lovelock, biophysicist.
• Study is called geophysiology.
• Earth has unique environmental conditions by
  comparison to other planets.
• Due to active intervention by living biota to
  create and sustain a livable environment.
• Earth operates as a single superorganism.
• May be thresholds of disruption beyond which the
  nature may not be able to recover.
• Interactions between organisms the physical
  environment can lead to global self-regulation.

4
Cycling of Materials

• Maintenance of the ideal conditions of the
  biosphere requires constant recycling of
  materials.
• Many cycles exist. We will study
• Carbon
• Nitrogen
• Phosphorus
• Sulfur
• Water
• These are materials used to make the chemical
  compounds of cells.

5
Carbon Cycle

• Carbon
• structural component of organic molecules
• Forms chemical energy-holding bonds which are
  stored.
• in atmosphere?
• Sinks on planet

6
Carbon Cycle

• Photosynthesis.
• Respiration.
• Part of cellular structure in organisms
• Digestion of fungi and bacteria.
• Present in Coal and oil.

7
Carbon Cycle (cont.)

• 6. Released when burning fossil fuels.
• 7. Ocean as a sink.
• 8. Limestone deposits.
• 9. Erosion of limestone.
• 10. Recycled by earth processes.

8
Carbon Cycle Model
9
Animation

• Carbon Cycle animation

10
Human Intervention in the Carbon Cycle

• Greenhouse gas
• Increase in CO2 due to human activities
• Climate change (global warming) effects

11
Nitrogen Cycle

• Organisms need nitrogen by humans to make many
  compounds.
• Nitrogen is the most abundant gas in atmosphere.
  What is the ?

12
Step 1 - Nitrogen Fixation

• This step is done in soil and water environments
  by bacteria
• a bacteria which lives inside nodules on roots of
  legumes (beans, peas, woody plants) also fix
  nitrogen.
• Lightning discharges, combustion, volcanic action
  and industrial processes can also fix nitrogen

13
Step 2 - Nitrification

• Converts ammonia to nitrate.
• Step 3 - Assimilation
• Plant roots absorb the nitrate and animals eat
  plants

14
Step 4 - Ammonification

• Bacteria eat waste of animals and dead bodies and
  convert the nitrogen into ammonia
• Step 5 Dentrification
• The nitrogen goes back into the atmosphere

15
Nitrogen Cycle
16
Nitrogen Cycle

• Nitrogen Cycle animation

17
Human Interventions in N-Cycle

• Internal Combustion Engine Exhaust
• Farming
• Mining
• Deforestation
• Cattle Waste and Fertilizers

18
Phosphorus Cycle

• Organisms need phosphorus
• Not present in every place on planet
• Transported in aqueous form
• Cycle time is very long

19
Phosphorus Cycle Steps

• Plants uptake
• Erosion of rock
• Animals eat
• Decomposers eat carcasses
• Feces into soil -gt PO4-3
• Erosion of soil in oceans
• Uplift of rock

20
Human Interventions in Phosphorus Cycle

• Mining
• Deforestation

21
Phosphorus Cycle

• http//www.mhhe.com/biosci/genbio/tlw3/eBridge/Chp
  29/29_keypoints.mhtml

22
Sulfur Cycle

• Organisms need sulfur.
• Where is most of sulfur located?
• Cycle complicated by large number of oxidation
  states
• Hydrogen sulfide (H2S)
• Sulfur dioxide (SO2)
• Sulfate ion (SO4-2)
• Sulfur

23
Sulfur Cycle Steps

• Erosion
• Seaspray
• Forest fires dust storms
• Volcanoes
• Acid Rain

24
Sulfur Cycle Steps (cont.)

• Plant uptake (SO4-2)
• Animals eat plants
• Bacteria convert sulfates to hydrogen sulfide gas
• Bacteria in anaerobic environment uses hydrogen
  sulfide instead of water

25
Sulfur Cycle

• http//www.mhhe.com/biosci/genbio/tlw3/eBridge/Chp
  29/29_keypoints.mhtml

26
Human Interventions of Sulfur Cycle

• Burn coal -gt release sulfur dioxide (SO2)
• -gt acid rain
• Smelting ores -gt release sulfur dioxide (SO2) -gt
  acid rain
• Mining sulfur -gt sulfuric acid

27
Hydrologic Cycle

• Organisms use water for chemical reactions
  transport
• Water continuously circulates from ocean to
  atmosphere to land to ocean

28
Solar Radiation
29
Solar Radiation

• Sun supplies enormous amount of energy
• Top of atmosphere 1330 watts/sq meter
• Visible light passes undiminished
• Ozone absorption
• Infrared absorbed by CO2 and Water in atmosphere
• Albedo

30
Solar Radiation (cont.)

• Solar radiation that falls on earth causes many
  things to happen
• Ultimately all this energy is lost into space as
  heat (infrared energy)
• Infrared energy emitted from earths surface is
  greater than incoming solar radiation

31
Temperature Latitude

• Local variation in temperature
• Suns rays hit earth at different angles
• Equator
• Poles
• Animation

32
Temperature Seasons

• Seasons are determined by what?
• Inclination
• Seasons
• Vernal Equinox
• Summer Solstice
• Autumnal Equinox
• Winter Solstice

33
Atmosphere

• Composition
• Nitrogen
• Oxygen
• Remaining
• Argon
• Carbon Dioxide
• Neon
• Helium
• Methane
• Ozone, Dust Particles, CFC

34
Layers of Atmosphere

• Troposphere
• Location
• Depth
• What occurs in this layer
• Composition
• Temperature range
• Tropopause -

35
Layers of Atmosphere (cont)

• Stratosphere
• Depth
• Temperature
• Composition
• Stratosphere ozone

36
Layers of Atmosphere (cont)

• Mesosphere
• Depth
• Middle layer
• Temperature
• Thermosphere
• Depth
• Temperature
• Aurora occurs in this layer

37
Layers of Atmosphere
38
Atmospheric Circulation

• Caused by ?
• Convection Currents
• Sun heats earth surface
• Heat is transferred to adjacent air layers
  causing it to expand
• Lighter air rises and is replaced by cooler air
• Result is vertical convection current

39
Atmospheric Circulation (cont)

• Most air recirculates immediately however some
  splits and flows towards poles
• Air chills enough to sink to surface at 30
  degrees north and south latitudes.
• Similar spilt and flow occurs at 60 degrees north
  and south latitudes.
• Transfers heat from equator and cold air from
  poles to moderate earths temperature.

40
Atmospheric Circulation (cont)

• Coriolis effect the tendency for the air layers
  close to the earths surface to be pulled in the
  direction of the earths rotation.
• Coriolis effect influences the direction of the
  wind
• Trade winds north and south of equator
• Westerlies north of 30 degree N (latitude)
  south of 30 degree S (latitude)
• Polar Easterlies north of 60 degree N
  (latitude) south of 60 degree S (latitude).

41
Atmospheric Circulation (cont)

• Wind circulation

42
The Global Ocean

• Four sections
• Surface ocean currents
• Gyres circular ocean currents generated by
  prevailing winds
• Coriolis effect
• Northern Hemisphere
• Southern Hemisphere
• Coriolis effect video

43
Animation

• Ocean Currents

44
Vertical Mixing of Ocean Water

• Density of seawater
• Colder/saltier water vs. warmer/less salty water
• Ocean Conveyor belt affects ?
• Gulf Stream North Atlantic Drift
• Ocean conveyor belt is changing and can shift in
  relatively short period of time.

45
Animation

• Ocean conveyor belt

46
Ocean Interactions with the Atmosphere

• Ocean and atmosphere are strongly linked
• El Nino Southern Oscillation (ENSO) good
  example.
• Normally
• warm surface water of the Pacific Ocean is stored
  to the west near Indonesia
• Equatorial trade winds generate convection
  currents of moist air
• Thunderheads bring torrential rain to Northern
  Australia and Southeast Asia
• Winds in troposphere carry warm dry air to Mexico
  South America resulting in deserts
• Trade winds back towards Indonesia drive surface
  water to the west. This water is replaced by
  cold, nutrient-rich deep water off coast of South
  America. Supports anchovies and finfish

47
ENSO

• Every 3 to 5 years, things change
• Low pressure in Indonesia collapses
• Tends to happen in winter (northern hemisphere)
• Surface water off South America and Mexico become
  warmer
• Ocean currents slow down and stop or even flow
  eastward
• Colder nutrient-rich deep water is not pulled
  towards surface
• Lack of nutrient-rich water results in decrease
  in anchovies and other marine fish
• Results in heavy snows in Western U.S., drought
  in Indonesia
• Jet stream normally over Canada, splits and is
  drawn over US.
• Then, the jet stream pulls moist air from Pacific
  and Gulf of Mexico inland resulting in intense
  rain from California to Midwest.

48
Animation

• El Nino animation

49
La Nina

• Occurs when surface water temperature in Eastern
  Pacific becomes unusually cool westbound trade
  winds unusually strong
• Intervening years of El Nino
• Results in wetter winters in Pacific Northwest,
  warmer weather in Southeast, and drought in
  Southwest
• Atlantic hurricanes are also stronger

50
Weather Climate

• Weather
• Climate
• Two factors determine an areas climate

51
Climate Zones

• Humid equatorial
• Dry
• Humid temperate
• Humid cold
• Cold polar
• Highland climate
• Image

52
Precipitation

• Greatest where warm air passes over the ocean
  where it picks up moisture and is then cooled.
• Least in the rain shadows of mountain ranges or
  in continental interiors.

53
Rain Shadows

• Air carried by currents hits mountains which
  force air to rise
• Air cools as it gains altitude, clouds form and
  precipitation occurs
• As air mass moves down other side of mountain it
  is warmed and dry, picking up any remaining
  moisture in plants.
• Deserts result
• Example Sierra Nevada Mono Lake

54
Rain Shadow Animation

• Rainshadow

55
Tornadoes

• Swirling funnel clouds that form over land
• Associated with severe thunderstorms
• Generated when strong, dry air cold fronts from
  Canada collide with warm humid air moving north
  from Gulf of Mexico.
• The greater the air temperature difference, the
  more powerful the storm.
• Warm air rises rapidly over dense, cold air
  creating intense vertical convection currents
  that generate towering thunderheads

56
Tornadoes (cont)

• What causes spinning?
• Differential air speed called shear forces roll
  air ahead of front (like rolling clay between
  your hands).
• Wind speeds
• Width -
• Low pressure in center implodes houses, sucks
  people out of windows and hurls large objects
  across countryside.

57
Cyclones

• Created when strong winds pick up moisture over
  warm, surface water of tropical oceans.
• Spin as a result of Earths rotation.
• Called hurricanes in Atlantic eastern Pacific,
  typhoons in western Pacific, cyclones in Indian
  Ocean.
• High winds _________ and walls of water called
  storm surge are created. Storm surge creates
  waves up to __________.
• Width

58
Climatic Changes

• Random pattern brought about by chance
  interactions OR
• Periodic patterns due to

59
Volcanoes

• Sources of most of the earths crust
• Source of some of Earths most fertile soil
• Hazards include
• Nuees ardentes (French for glowing clouds) which
  are mixtures of hot gases and ash (Pompeii)
• Mudslides
• Ash dust
• Sulfur emissions

60
Earthquakes

• Sudden movements of the earths crust that occur
  along faults (planes of weakness) where one rock
  mass slides past another one.
• Friction and Stress

61
Animations of Earthquakes

• Plate tectonics

62
Earthquakes (cont)

• How are they measured
• Richter Scale
• Moment Magnitude scale

63
Earthquake Hazards

• Ground shaking
• Fault displacement
• Liquefaction
• Landslides
• Tsunami