Download Closer to Poles (c)

Chapter 5
Ecosystems and the Physical Environment
Overview of Chapter 5
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Biogeochemical Cycles
Solar Radiation
The Atmosphere
The Global Ocean
Weather and Climate
Internal Planetary Processes
Biogeochemical Cycles
Matter moves between
ecosystems, biotic & abiotic
environments, and organisms
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Unlike energy
Biogeochemical cycling involves
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Biological, geologic and
chemical interactions
Five major cycles:
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Carbon, Nitrogen, Phosphorus,
Sulfur and Water (hydrologic)
The Carbon Cycle
Cycling of Materials within Ecosystems
Nitrogen cycle:
Biological
nitrogen
fixation
NH3 &
NH4-
Atmospheric
nitrogen (N2)
Nitrogen
fixation
by humans
Decomposition
Internal
cycling
Nitrification
Denitrification
Plant & animal
proteins
Assimilation
NO3
-
The Nitrogen Cycle
Cycling of Materials within Ecosystems
Phosphorus cycle:
Phosphate rocks
Excretion /
decomposition
Phosphate
mining
Erosion
Internal
cycling
Marine
organisms
Marine
sediments
Fertilizer
containing
phosphates
Dissolved
phosphates
Erosion
Animals, crops
Internal
cycling
Soil phosphates
The Phosphorus Cycle
The Sulfur Cycle
The Water (Hydrologic) Cycle
Solar Radiation
Sun provides energy for life, powers
biogeochemical cycles, and determines climate
69% of incoming solar
radiation is absorbed by
atmosphere and earth
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What happens to the
rest?
Albedo
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The reflectance of solar
energy off earth’s surface
Dark colors = ???
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Forests and ocean
Light colors = ???
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Ice caps, glaciers, snow
Temperature Changes with Latitude
Solar energy does not hit earth uniformly
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Due to earth’s spherical shape and tilt
Equator (a)
Closer to Poles (c)
High concentration
Little Reflection
High Temperature
Low concentration
Higher Reflection
Low Temperature
Temperature Changes with Season
Seasons
determined by
earth’s tilt
(23.5°)
Causes each
hemisphere to
tilt toward the
sun for half
the year
Northern Hemisphere tilts towards the sun from
March 21- September 22 (warm season)
The Atmosphere
Invisible layer of gases that
envelopes earth
Content
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78% Nitrogen
21% Oxygen
1% Argon, Carbon dioxide,
H2O, Neon and Helium
Density decreases with
distance from earth
Shields earth from high
energy radiation
Atmospheric Layers
Exosphere (500km and up)
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Outermost layer
Atmosphere continues to thin
until converges with
interplanetary space
Thermosphere (80-500km)
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Gases in thin air absorb x-rays
and short-wave UV radiation =
very hot
Source of aurora
Atmospheric Layers
Mesosphere (45-80km)
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Temperature decreases with
altitude
Stratosphere (10-45km)
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Temperature increases with
altitude- very stable
Ozone layer absorbs UV
Troposphere (0-10km)
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Where weather occurs
Temperature decreases with
altitude
Atmospheric Circulation
Near Equator
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Warm air rises, cools and
splits to flow towards the
poles
~30°N&S sinks back to
surface
Air moves along surface
back towards equator
This occurs at higher
latitudes as well
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Moves heat from equator
to the poles
Surface Winds
Winds blow from high
to low pressure
Large winds due in
part to pressures
caused by global
circulation of air
High
Low
High
Low
High
Low
High
Coriolis Effect
Earth’s rotation influences direction of wind
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Earth rotates from East to West
Deflects wind from straight-line path
Coriolis Effect
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Influence of the earth’s rotation on movement
of air and fluids
Turns them Right in the Northern Hemisphere
Turns them Left in the Southern Hemisphere
Coriolis Effect
Visualize it as a Merry-Go-Round (see below)
Global Ocean Circulation
Prevailing winds produce ocean currents and
generate gyres
Example: the North Atlantic Ocean
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Trade winds blow west
Westerlies blow east
Creates a clockwise gyre in the North Atlantic
Circular pattern influenced by coriolis effect
Global Ocean Circulation
Westerlies
Trade winds
Position of Landmasses
Large landmasses in
the Northern
Hemisphere help to
dictate ocean
currents and flow
Very little land in
the Southern
Hemisphere
Vertical Mixing of Ocean
Ocean Interaction with AtmosphereENSO
El Niño-Southern Oscillation (ENSO)
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Def: periodic large scale warming of surface waters of
tropical eastern Pacific Ocean
Alters ocean and atmospheric circulation patterns
Normal conditions- westward blowing tradewinds keep
warmest water in western Pacific
Ocean Interaction with AtmosphereENSO
ENSO conditionstrade winds weaken
and warm water
expands eastward
to South America
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Big effect on
fishing industry off
South America
ENSO Climate Patterns
Weather and Climate
Weather
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The conditions in the atmosphere at a given
place and time
Temperature, precipitation, cloudiness, etc.
Climate
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The average weather conditions that occur in a
place over a period of years
2 most important factors: temperature and
precipitation
Earth has many climates
Weather and Climate
Precipitation:
• Atacama Desert in Chile = 0.05 cm / year
• Mount Waialeale in Hawaii = 1200 cm /
year
• What is the annual precipitation in your
area?
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Kaiserslautern gets nearly 100cm a year.
Rain Shadows
Mountains force humid air to rise
Air cools with altitude, clouds form and
precipitation occurs (windward side)
Dry air mass moves down opposite leeward
side of mountain
Severe Weather Events:
Tornadoes
Powerful funnel of air associated with a
severe thunderstorm
Formation:
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Mass of cool dry air collides with warm humid air
Produces a strong updraft of spinning air under
a cloud
Spinning funnel becomes tornado when it
descends from cloud
Wind velocity= up to 300mph
Width ranges from 1m to 3.2km
Tornadoes
Frequency of tornados annually per 100,000 km2
Tornado Alley (US)
40
Sydney, Australia
8
United Kingdom
1
Bangledesh
0.6
Severe Weather Events:
Tropical Cyclones
Giant rotating tropical storms
Wind >119km per hour
Formation
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Strong winds pick up moisture over warm surface
waters
Starts to spin due to Earth’s
rotation
Spin causes upward spiral
of clouds
Damaging on land
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High winds
Storm surges
Severe Weather Events:
Tropical Cyclones
Tropical cyclones
Atlantic Ocean = hurricanes
Pacific Ocean = typhoons
Indian Ocean = cyclones
Internal Planetary Processes
Layers of the earth
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Lithosphere
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Outermost rigid rock layer composed of plates
Asthenosphere
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Lower mantle comprised of hot soft rock
Plate Tectonics- study of the processes by
which the lithospheric plates move over
the asthenosphere
Plate Boundary- where 2 plates meet
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Common site of earthquakes and volcanoes
Plates and Plate Boundaries
Internal Planetary Processes
Volcanoes
Most volcanoes occur along subduction
zones
Internal Planetary Processes
Volcanoes
Some occur along spreading
zones
Few, such as Hawaiian Islands, not
associated with plates.
Types of Plate Boundaries
Divergent Plate Boundary-2
plates move apart
Convergent Plate Boundary-2
plates move together (may
get subduction)
Types of Plate Boundaries
Transform Plate
BoundaryTwo plates move
horizontally in
opposite, parallel
directions
Earthquakes
Caused by the release of accumulated energy
as rocks in the lithosphere suddenly shift
or break
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Occur along faults
Energy released as seismic wave
Focus- the site where the earthquake
originates below the surface
Epicenter- located on the earth’s surface,
directly above the focus
Richter scale and the moment magnitude
scales are used to measure the magnitude
Tsunami
Giant undersea wave caused by an
earthquake, volcanic eruption or landslide
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Travel > 450mph
Tsunami wave may be 1m deep in ocean
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Becomes 30.5m high on shore
Magnitude 9.3 earthquake in Indian Ocean
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Triggered tsunami that killed over 230,000
people in South Asia and Africa