The Biosphere

1
The Biosphere

• Biology 1030
• Principles of Biology

2
Climate

• Average weather condition in a region
• Affected by
• amount of incoming solar radiation
• prevailing winds
• elevation

3
The Atmosphere

• Three layers
• Outer mesosphere
• Middle stratosphere (includes ozone layer)
• Inner troposphere (where air is warmed by the
  greenhouse effect)

4
Warming the Atmosphere

• Solar energy warms the atmosphere and sets global
  air circulation patterns in motion

5
Rotation and Wind Direction

• Earth rotates faster under the air at the equator
  than it does at the poles
• Deflection east and west

6
Seasonal Variation

• Northern end of Earths axis tilts toward sun in
  June and away in December
• Difference in tilt causes differences in sunlight
  intensity and day length
• The greater the distance from the equator, the
  more pronounced the seasonal changes

7
Varying Temperatures
8
Pollutants

• Substances with which an ecosystem has had no
  prior evolutionary experience
• No adaptive mechanisms are in place to deal with
  them

9
Ozone Thinning

• In early spring and summer ozone layer over
  Antarctica thins
• Seasonal loss of ozone is at highest level ever
  recorded

10
Effect of Ozone Thinning

• Increased amount of UV radiation reaches Earths
  surface
• UV damages DNA and negatively affects human
  health
• UV also affects plants, lowers primary
  productivity

11
Air Pollutants

• Carbon oxides
• Sulfur oxides
• Nitrogen oxides
• Volatile organic compounds
• Photochemical oxidants
• Suspended particles

12
Protecting the Ozone Layer

• CFC production has been halted in developed
  countries, will be phased out in developing
  countries
• Methyl bromide will be phased out
• Even with bans it will take more than 50 years
  for ozone levels to recover

13
Thermal Inversion

• Weather pattern in which a layer of cool, dense
  air is trapped beneath a layer of warm air

cooler air
normal circulation
cool air
warm air
cool air
warm inversion air
cool air
14
Industrial Smog

• Gray-air smog
• Forms over cities that burn large amounts of coal
  and heavy fuel oils mainly in developing
  countries
• Main components are sulfur oxides and suspended
  particles

15
Photochemical Smog

• Brown-air smog
• Forms when sunlight interacts with components
  from automobile exhaust
• Nitrogen oxides are the main culprits
• Hot days contribute to formation

16
Acid Deposition

• Caused by the release of sulfur and nitrogen
  oxides
• Coal-burning power plants and motor vehicles are
  major sources

17
Ocean Currents

• Upper waters move in currents that distribute
  nutrients and affect regional climates

18
Rain Shadow

• Air rises on the windward side, loses moisture
  before passing over the mountain

19
Coastal Breezes

• Breeze blows in direction of warmer region
• Direction varies with time of day

20
Biogeographic Realms

• Six areas in which plants and animals are
  somewhat similar
• Maintain their identity because of climate and
  physical barriers that tend to maintain isolation
  between species

21
Biomes

• Regions of land characterized by habitat
  conditions and community structure
• Distinctive biomes prevail at certain latitudes
  and elevations

22
nearctic
neotropical
23
Hot Spots

• Portions of biomes that show the greatest
  biodiversity
• Conservationists are working to inventory and
  protect these regions
• 24 hot spots hold more than half of all
  terrestrial species

24
Deserts

• Less than 10 centimeters annual rainfall, high
  level of evaporation
• Tend to occur at 30 degrees north and south and
  in rain shadows
• One third of land surface is arid or semiarid

25
Dry Shrublands and Woodlands

• Semiarid regions with cooler, wet winters and
  hot, dry summers
• Tend to occur in western or southern coastal
  regions between latitudes of 30 and 40 degrees

26
Forest Biomes

• Tall trees form a continuous canopy
• Evergreen broadleaves in tropical latitudes
• Deciduous broadleaves in most temperate latitudes
• Evergreen conifers at high temperate elevations
  and at high latitudes

27
Arctic Tundra

• Occurs at high latitudes between polar ice cap
  and boreal forests
• Summers are short and snow-free
• Permafrost lies beneath surface, causes
  waterlogging in summer
• Nutrient cycling is very slow

28
Alpine Tundra

• Occurs at high elevations throughout the world
• No underlying permafrost
• Plants are low, cushions or mats as in arctic
  tundra

29
Lakes

• Bodies of standing freshwater
• Eutrophic lake is shallow, nutrient-rich, has
  high primary productivity
• Oligotrophic lake is deep, nutrient-poor, has low
  primary productivity

30
Lake Zonation
LITTORAL
LITTORAL
LIMNETIC
limit of effective light penetration
PROFUNDAL
31
Thermal Layering

• In temperate-zone lakes, water can form distinct
  layers during summer

wind
THERMOCLINE
32
Seasonal Overturn

• In spring and fall, temperatures in the lake
  become more uniform
• Oxygen-rich surface waters mix with deeper
  oxygen-poor layers
• Nutrients that accumulated at bottom are brought
  to the surface

33
Eutrophication

• Enrichment of a body of water with nutrients
• Can occur naturally over long time span
• Can be triggered by pollutants

34
Estuary

• Partially enclosed area where saltwater and
  freshwater mix
• Dominated by salt-tolerant plants
• Examples are Chesapeake Bay, San Francisco Bay,
  salt marshes of New England

35
Mangrove Wetlands

• Tropical saltwater ecosystem
• Form in nutrient-rich tidal flats
• Dominant plants are salt-tolerant mangroves
• Florida, Southeast Asia

36
Coral Reefs

• Develop in clear, warm waters near coasts or
  around volcanic islands, mainly between latitudes
  25 north and south
• Coral bleaching is on the rise occurs when
  sea temperatures rise

37
The Open Ocean
38
Phytoplankton

• Floating or weakly swimming photoautotrophs form
  the base for most oceanic food webs
• Ultraplankton are photosynthetic bacteria

39
Deep Ocean Food Webs

• Regions too dark for photosynthesis
• Marine snow supports a detrital food web
• Organic matter drifts down from shallower water
• Diverse species migrate up and down in water
  column daily

40
Hydrothermal Vents

• Openings in ocean floor that spew mineral-rich,
  superheated water
• Primary producers are chemoautotrophic bacteria
  use sulfides as energy source
• Life may have originated in similar conditions on
  early Earth

41
Upwelling

• Upward movement of water along a coast replaces
  surface waters that move away from shore

42
Cholera Connection

• Cholera outbreaks are correlated with rises in
  sea temperature
• Dormant stage of causative organism lives in
  copepods
• Copepod population increases when phytoplankton
  increase in warming seas