Transcript APES review topics

APES review topics
Cycles
• All nutrients on earth have to cycle: matter is
neither created nor destroyed.
• All nutrients pass through both living and non
living components of the ecosystem
• Living things need all nutrients and can only get
them through consumption (animals) or uptake
(plants)
• Nitrogen cycle is driven by bacteria
• Hydrologic cycle is driven by the sun, water
vapor
• Carbon cycle: greenhouse effect, carbon
sequestration.
Soils
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O layer- organic material, decaying life
A layer- topsoil, humus
B layer- subsoil, some broken parent material
C layer- parent material bedrock
Infiltration: the downward movement of water through soil.
Leaching: dissolving of minerals and organic matter in
upper layers carrying them to lower layers.
The soil type determines the degree of infiltration and
leaching.
Sand- 0.05-2 mm
Silt- 0.002-0.05 mm
Clay- less than 0.002 mm
Soil nutrients are determined by the type of vegetation
which is determined by the climate
Weathering and erosion
• Soil erosion lowers soil fertility and can overload nearby
bodies of water with eroded sediment.
– Sheet erosion: surface water or wind peel off thin layers of soil.
– Rill erosion: fast-flowing little rivulets of surface water make small
channels.
– Gully erosion: fast-flowing water join together to cut wider and
deeper ditches or gullies.
• Soil erosion is the movement of soil components, especially
surface litter and topsoil, by wind or water.
• Soil erosion increases through activities such as farming,
logging, construction, overgrazing, and off-road vehicles.
• Desertification- land becoming more desert like due to soil
erosion
• Weathering- biologic, chemical and mechanical
• Weathering is the breaking apart of rock material into
smaller particles
Global warming
• Proxy Data
– Ice cores, Tree Rings and Lake Core Sediments
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major factors shape the earth’s climate:
– The sun.
– Greenhouse effect that warms the earth’s lower troposphere and
surface because of the presence of greenhouse gases.
– Oceans store CO2 and heat, evaporate and receive water, move
stored heat to other parts of the world.
– Natural cooling process through water vapor in the troposphere
(heat rises).
• Between 1979 and 2005, average Arctic sea ice dropped
20%
• If seas levels rise by 9-88cm during this century, most of
the Maldives islands and their coral reefs will be flooded.
• “global warming” refers to the current increase in global
temperatures which is suspected to be caused by
anthropogenic sources (cars, factories, etc)
Plate tectonics
The Earth’s Major Tectonic Plates
Spreading
center
Collision between
two continents
Subduction
zone
Continental
crust
Ocean
trench
Oceanic
crust
Oceanic
crust
Continental
crust
Material cools Cold dense
as it reaches material falls
the outer back through
mantle
mantle
Mantle
convection
cell
Two plates move
towards each other.
One is subducted
back into the mantle
on a falling convection
current.
Hot
material
rising
through
the
mantle
Mantle
Hot outer
core Inner
core
JUAN DE
FUCA PLATE
EURASIAN PLATE
NORTH
AMERICAN
PLATE
ANATOLIAN
PLATE
CARIBBEAN
PLATE
ARABIAN
AFRICAN PLATE
PLATE
PACIFIC
PLATE
SOUTH
AMERICAN
NAZCA PLATE
PLATE
SOMALIAN
SUBPLATE
CHINA
SUBPLATE
PHILIPPINE
PLATE
INDIAAUSTRALIAN
PLATE
ANTARCTIC PLATE
Divergent plate
boundaries
Convergent plate
boundaries
Transform
faults
Benefits of the ocean
• Great diversity- coral reefs
• Coral bleaching- waters getting too warm
causing coral (animals) to die leaving behind
only the white limestone
• Coral reefs protect main land from high surf and
storms.
• Huge amount of carbon sequestration
• estuaries are where rivers meet the sea. Help
control flooding, very productive ecosystem.
– Filter toxic pollution, excess plant nutrients, sediments
and other pollutants.
Ozone depletion
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How to make ozone:
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O2 + High Energy UV  O + O
O2 + O  O3
CFC’s – chlorofluorocarbons
Stratospheric ozone depletion
Harmful effects of less ozone:
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Melanoma
Basal Cell Carcinomas
Squamous Cell Carcinomas
Other Skin Damage
Cataracts and Other Eye Damage
Immune Suppression
Inhibit photosynthesis in plankton
Air pollution
• Carbon oxides- incomplete combustion of
carbon-containing materials.
– 93% of carbon dioxide (CO2) in the troposphere
occurs as a result of the carbon cycle.
– 7% of CO2 in the troposphere occurs as a result of
human activities (mostly burning fossil fuels).
• Nitrogen oxides- nitrogen and oxygen gas in air
react at the high-combustion temperatures in
automobile engines and coal-burning plants.
• Sulfur Oxides- 2/3 come from coal and oil
combustion
– SO2 in the atmosphere can be converted to sulfuric
acid (H2SO4) and sulfate salts (SO42-) that return to
earth as a component of acid deposition.
Air Pollution
• Suspended particulates (SPM)
– The most harmful forms of SPM are fine particles
(PM-10, with an average diameter < 10 micrometers)
and ultrafine particles (PM-2.5).
• Troposphere Ozone- highly reactive gas, major
component of photochemical smog.
– UV + VOC = NOx = Ozone
– NOx: Released mainly from burning of fossil fuels
– VOCs: emitted in gasoline fumes, and in the
evaporation of solvents
• Nitrogen dioxide- A brown gas which contributes
to urban haze
– Can be converted in the atmosphere to HNO3 which
then is deposited as acid deposition
Water pollution