AP Environmental Study Session 6

Tropical Storms

• When moisture laden air blows over warm ocean water a low pressure system forms

• Winds will spiral around the depression• What’s the difference between a hurricane and

a typhoon?– Location Location Location

• As the systems moves over the warm water:– Pulls water vapor up into the air– Vapor condenses and adds energy

El Nino / La Nina

• Occurs every 3 – 7 years• Normal:– Trade Winds move warm water off the coast– Keeps coastal water cool and with lots of nutrients

• During El Nino:– Trade Winds are weakened or reversed– Moves warm water to the coast– Water contains less oxygen and nutrients

• During La Nina:– Coastal waters are colder than normal

Upwelling and Redtides

• Upwelling:– Seasonal movement of cold, deep, nutrient rich

water to the surface– Large influx of nutrients causes exponential

increases in algae populations• Redtide:– Dinoflagellate blooms which produce toxins

The Hydrosphere

Salt Water and Oceans

• Ocean’s salinity varies, but it about 3.5%– For every 1 liter of sea water there are 35 grams of

salt• Barrier Islands:– Created by deposited sediments– Continually shifting– Act as a buffer zone to shorelines behind them

Coral Reefs

• A type of barrier island• Built by cnidarians– Secrete a hard

calciferous shells• Diversity Reserviors– Corals provide homes

and food for numerous species

– An Oasis in the Desert

Ocean Zones

• Coastal:– Area between the shore and the edge of the

continental shelf• Euphotic: – Has the highest levels of dissolved oxygen– Most sunlight, >>>photosynthesis– Warmest region

• Bathyal:– Below Euphotic Zone, < sunlight– Not enough light for photosynthesis– Cooler than Euphotic

• Abyssal:– Deepest region of the ocean– Extremely cold temps– Very low dissolved oxygen

levels– Lots of nutrients– >>> Pressure

Ocean Currents• Thermohaline Conveyor– Large circulation of sea water– Contributes to the climates throughout the world– Driven by differences in temp, salinity, density and

Earth’s rotation

Freshwater

• Contains small amounts of salts, not near the extent of the ocean ( < 1.0% salt )

• Formed by the accumulation of liquid atmospheric moisture and melted snow

• Lakes, rivers, streams, ground water

Vocab regarding Freshwater

• Watershed:– An area that drains an area of land into a particular river or stream

• Estuaries:– Freshwater with increased nutrients, salts, and sediments– ‘arms’ of the ocean that extend inland– Salt water marshes, mangrove forests, bays, inlets

• Wetlands:– Areas where excess water sits on the surface of the Earth– Marshes, swamps, bogs, prairie potholes, flood plains

• Deltas:– Areas of rivers/streams that meet the ocean– Significantly slowed flow velocity causes sediments to fall to the

bottom

Freshwater Stratification

• Epilimnion:– Upper most, photosynthetic, warmer, less dense, most

oxygenated• Hypolimnion:– Lower, more dense, less oxygenated, cooler

• Thermocline– The transition between the Epi- and Hypo-limnion where a

dramatic temperature shift is experienced• Pycnocline– The transition between different layers of water which have

differing densities

Freshwater Stratification

• Littoral Zone:– From the shoreline to the point where rooted plants stop

growing– Abundant sunlight and photosynthesis

• Limnetic Zone:– Surface of open water– Abundant sunlight and photosynthesis

• Profundal Zone:– Aphotic zone = no sunlight

• Benthic Zone:– Deepest layer of water– Low temps, low oxygen

Human Water Use Key Words

• Riparian Right– People have legal rights to use a riparian area

• Prior Appropriation– Water is given to people who have traditionally used it in the past

• Interbasin Transfer– Water moved long distances away from their original source

• Confined/Unconfined Aquifer– No water is readily transported / water can freely move vertically

or horizontally• Water-stressed

– Annual supply of 1,000 – 2,000 cubic meters per person• Water-scarce

– < 1,000 cubic meters of water per person

Human Uses