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Chapter 5
Ecosystems and the Physical Environment
Importance of this Chapter
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This semester, we will focus most of our
efforts on the subjects of ENERGY AND
CLIMATE CHANGE.
These are ABIOTIC factors. So we need
to understand our Abiotic Environment.
This chapter will build a foundation to
support our learning for the rest of the
semester.
PLEASE FOCUS ON THIS MATERIAL
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
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Matter moves between
ecosystems, biotic & abiotic
environments, and organisms
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Biogeochemical cycling
involves
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Unlike energy
Biological, geologic and
chemical interactions
Five major cycles:
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Carbon, Nitrogen, Phosphorus,
Sulfur and Water (hydrologic)
The Water (Hydrologic) Cycle
Simplified Water (Hydrologic)
Cycle
EVAPORATION
TRANSPIRATION
PERCOLATION
CONDENSATION
PRECIPITATION
The Carbon Cycle
Simplified Carbon Cycle
BURNING
FOSSIL FUEL
CELLULAR
RESPIRATION
ACID RAIN
DISSOLVES PHOTOINTO WATER SYNTHESIS
COW
FARTS
FOSSIL
FUEL
STORAGE
UNDERGROUND
The Nitrogen Cycle
Know Importance of Nitrogen Fixation & Overall Roll of
Bacteria
The Phosphorus Cycle
This Cycle Never Enters Atmosphere
The Sulfur Cycle
Know that the cycle exists, we won’t focus on this
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Solar Radiation-VERY IMPORTANT
CONCEPT
Sun provides energy for life, powers
biogeochemical cycles, and determines climate
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69% of incoming solar
radiation is absorbed by
atmosphere and earth
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Remainder is reflected
Albedo
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The reflectance of solar
energy off earth’s surface
Dark colors = low albedo
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Forests and ocean
Light colors = high albedo
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Ice caps
Temperature Changes with Latitude
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Solar energy does not hit earth uniformly
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Due to earth’s spherical shape and tilt
Equator (a)
High concentration
Little Reflection
High Temperature
Closer to Poles (c)
From (a) to (c)
In diagram below
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
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Northern Hemisphere tilts towards the sun
from March 21- September 22 (warm season)
The Atmosphere
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Invisible layer of gases that
envelopes earth
Content
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21% Oxygen
78% Nitrogen
1% Argon, Carbon dioxide,
Neon and Helium
Density decreases with
distance from earth
Shields earth from high
energy radiation
Atmospheric Layers
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Troposphere (0-10km)
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Stratosphere (10-45km)
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Where weather occurs
Temperature decreases with
altitude
Temperature increases with
altitude- very stable
Ozone layer absorbs UV
Mesosphere (45-80km)
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Temperature decreases with
altitude
Atmospheric Layers
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Thermosphere (80-500km)
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Gases in thin air absorb x-rays
and short-wave UV radiation =
very hot
Source of aurora
Exosphere (500km and up)
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Outermost layer
Atmosphere continues to thin
until converges with
interplanetary space
Atmospheric Layers
The atmosphere may seem big,
but if you shrunk the Earth down
to the size of an apple;
The atmosphere
would be thinner
than the skin on
this apple (it is
fragile).
Atmospheric Circulation
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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
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Global convection
currents of air.
Winds blow from
high to low pressure
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Cold & dry air is
dense, creating high
pressure at the
ground.
Hot & humid air is
light, and is displaced
by cold & dry air (hot
air rises).
High
Low
High
Low
High
Low
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Coriolis Effect
Earth’s rotation influences
direction of wind
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Earth rotates from East to West
Objects at poles are moving slower
than objects at the equator.
Deflects wind from straight-line path
Coriolis Effect
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We don’t notice it, but things at the equator are
moving much faster than things in Anchorage.
This influences the movement of air and fluids
• Turns them Clockwise in the Northern Hemisphere
• Turns them Counterclockwise in the Southern
Hemisphere
Coriolis Effect
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Visualize it as a Merry-Go-Round (see below)
http://www.bing.com/videos/search?q=coriolis+effect+animation&mid=36B18
329995CA6548DD136B18329995CA6548DD1&view=detail&FORM=VIRE3
Global Ocean Circulation
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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
Westerlies
Position of Landmasses
Large landmasses in
the Northern
Hemisphere help to
dictate ocean
currents and flow
Very little land in
the Southern
Hemisphere
Ocean Conveyor Belt- Vertical
Mixing of Ocean
Upwelling
at South
America
Ocean Interaction with AtmosphereENSO
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El Niño-Southern Oscillation (ENSO)
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Alters ocean and atmospheric circulation patterns
Normal conditions- westward blowing tradewinds
keep warmest water in western Pacific
ENSO conditions- trade winds weaken and warm
water expands eastward to South America
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Def: periodic large scale warming of surface waters of
tropical eastern Pacific Ocean
Big effect on fishing industry off South America
La Nina is the strengthening of trade winds,
cooling surface waters off South America.
ENSO Climate Patterns
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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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Weather and Climate
The average weather conditions that occur in a
place over a period of years
2 most important factors: temperature and
precipitation
Earth as many climates
In places where the weather never changes,
the climate and weather are the same.
World Climate Map
Rain Shadows
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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
Tornadoes
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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
Tropical Cyclone
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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
Internal Planetary Processes
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Layers of the earth
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Lithosphere
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Asthenosphere
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Outermost rigid rock layer composed of plates
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
Types of Plate Boundaries
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Divergent Plate
Boundary-2 plates move
apart
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Convergent Plate Boundary2 plates move together
(may get subduction)
Types of Plate Boundaries
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Transform Plate
Boundary- 2
plates move
horizontally in
opposite,
parallel
directions
Earthquakes
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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
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Giant undersea wave caused by an
earthquake, volcanic eruption or landslide
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Tsunami wave may be 1m deep in ocean
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Travel > 450mph
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