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• 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• 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 PlatesThe Earth’s Major Tectonic Plates

Spreading centerCollision between

two continentsOcean trench

Plate movement

Subduction zone

Oceanic crust

Continental crust

Continental crust

Material cools as it reaches

the outer mantle

Cold dense material falls back through

mantle

Hot material

rising through

the mantle

Mantle convection

cell

Two plates move towards each other. One is subducted back into the mantle on a falling convection current.

Mantle

Hot outer core Inner

core

Plate movementTe

cton

ic

plat

e

Oceanic tectonic

plate

Oceanic tectonic plate

Oceanic crust

EURASIAN PLATEEURASIAN PLATENORTH NORTH AMERICAN AMERICAN PLATEPLATE

ANATOLIAN ANATOLIAN PLATEPLATE

JUAN DE JUAN DE FUCA PLATEFUCA PLATE

CHINA CHINA SUBPLATESUBPLATE

CARIBBEAN CARIBBEAN PLATEPLATE

PHILIPPINE PHILIPPINE PLATEPLATE

ARABIAN ARABIAN PLATEPLATEAFRICAN AFRICAN

PLATEPLATEPACIFIC PACIFIC PLATEPLATE SOUTH SOUTH

AMERICAN AMERICAN PLATEPLATENAZCA NAZCA

PLATEPLATEINDIA-INDIA-

AUSTRALIAN AUSTRALIAN PLATEPLATE

SOMALIAN SOMALIAN SUBPLATESUBPLATE

ANTARCTIC PLATEANTARCTIC 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• How to make ozone:

– O2 + High Energy UV O + O– O2 + O O3

• CFC’s – chlorofluorocarbons• Stratospheric ozone depletion• Harmful effects of less ozone:

– 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