Chapter 15 Physical Oceanography

Words on Ch 15 Vocab Quiz 3/20/08 oceanographysea level oceanographysea level salinitythermocline salinitythermocline wavecrest wavecrest troughtide troughtide density currentsurface current density currentsurface current

Words on Ch 16 Vocab Quiz 3/21/08 wave refractionestuary wave refractionestuary longshore currentcontinental margin longshore currentcontinental margin continental shelfturbidity current continental shelfturbidity current abyssal plaindeep-sea trench abyssal plaindeep-sea trench mid-ocean ridgesseamount mid-ocean ridgesseamount

I. Ocean Water A. Origin of Oceans 1. Ancient volcanoes formed original oceans a) outgassing: volcanoes give off a lot of gases that is mostly water vapor b) this water vapor provided the necessary water to fill the oceans 2. Over millions of years enough water vapor went into the atmosphere to fill the oceans a) water fell as torrential rains to fill the low areas on the Earth (basins)

B. Composition of Oceans 1. Dissolved Salts a) Calcium, magnesium, potassium, and sodium came from rivers and groundwater b) Erupting volcanoes added chlorine and sulfur to the ocean

C. Salinity 1. Most salt is made of sodium and chlorine a) combine to form halite b) gives the ocean its salty taste 2. Salinity is the measure of the amount of dissolved solids in seawater a) measured in grams of salt per kilogram of ocean water b) ex 35 g Salt per kilogram of ocean water = 3.5% salinity

D. Element Removal 1. Oceans DO NOT get saltier 2. The salts and minerals are removed to help maintain a balance 3. Calcium and Silica are constantly removed from seawater a) marine animals, oysters, clams, and algae remove these elements 4. Iron is removed as it falls to the ocean bottom

E. Ocean Layering 1. Temperature Profile a) temperature decreases with depth b) Thermocline: the transition zone between the upper ocean that is warmed by the Sun and the cold lower ocean.

Answer the following in your notebook 1. Where did the water for the oceans come from? (according to scientific theory) 1. Where did the water for the oceans come from? (according to scientific theory) 2. How is some salt removed from ocean water? 2. How is some salt removed from ocean water? 3. What is the thermocline? 3. What is the thermocline? 4. What is the average salinity of today’s oceans? 4. What is the average salinity of today’s oceans?

II. Ocean Currents A. What are Ocean Currents? 1. A mass movement or flow of ocean water 2. Currents act like rivers within an ocean a) moves large volumes of water from one place to another

B. Surface Currents 1. Move water horizontally, parallel to shore 2. Surface currents are powered by wind a) friction between the wind and water drives the ocean in currents around the world 3. Surface Currents only move the upper few hundred meters of water

4 The Gulf Stream a) this current runs from the east coast of Florida to the west coast of the British Isles b) is 100km wide c) this current brings warm water up from the equator to the northern latitudes.

5. Factors Effecting Surface Currents a) currents in the northern hemisphere are always deflected to the right b) currents in the southern hemisphere are always deflected to the left c) currents are deflected by continents d) warm water currents are usually found on the east coast of continents e) cold water currents are usually found on the west coast of continents

C. Upwelling 1. Circulation that brings deep cold water to the ocean surface 2. Wind blowing offshore carries warm water away from the coast a) allows for cooler more nutrient rich water to rise to the surface b) attracts fish c) can cause large areas of dense fog Ex San Francisco D. Density Currents 1. More dense seawater sinks under less dense seawater 2. Mixes surface water farther into the ocean

Use your notes to answer the following in your notebook 1. What causes (powers) surface currents? 1. What causes (powers) surface currents? 2. Name one surface current that affects the USA? 2. Name one surface current that affects the USA? 3. Which direction are the surface currents deflected in the N. Hemisphere? 3. Which direction are the surface currents deflected in the N. Hemisphere? 4. In a density current which water sinks, more dense or less dense? 4. In a density current which water sinks, more dense or less dense? 5. What city in the USA is affected by upwellings? 5. What city in the USA is affected by upwellings?

III. Ocean Waves and Tides A. Waves 1. Caused by wind and the gravitational force of the moon a) on rare occasions are caused by earthquakes (tsunamis) 2. Caused by energy moving through the ocean

3. Wave Parts a) crest—highest point of a wave b) trough—lowest point of a wave c) wavelength—the distance between two crests of a wave d) wave height—measure of distance between a trough and a crest

4. Wave Breaking a) friction with the ocean bottom slows the bottom of a wave b) as the wave slows the crest and trough come closer together c) wave height increase and the top of the wave moves faster than the bottom of the wave causing it to roll over d) A breaker forms (collapsing wave)

B. Waves Caused by Wind 1. Friction between water and wind forms waves 2. Wave height depends on three things a) speed of the wind b) distance over which the wind blows (fetch) c) length of time the wind blows

C. Tides 1. The rise and fall of sea level a) caused by a giant wave, 1 or 2 meters high but thousands of kilometers long b) high tide—crest of the wave approaches c) low tide—trough of the wave approaches a few hours later d) one low tide-high tide cycle takes 12 hours and 25 minutes e) tidal range: the difference between the level of the ocean at high tide and low tide

2. Gravitational Effect of the Moon a) the moon’s gravity pulls the ocean water outward b) bulges of water forms directly under the moon and another forms on the opposite of the Earth c) these bulges appear as waves traveling across the ocean d) the Earth’s rotation cause high tide and low tide to occur in different locations around the Earth

D. Gravitational Effect of the Sun 1. Spring Tides a) the Earth, moon, and Sun are all lined up b) high tides are higher than normal c) low tides are lower than normal d) occur during full and new moon

2. Neap Tides a) the Earth, moon, and Sun form a right angle b) high tides are lower than normal c) low tides are higher than normal d) occur during first quarter and third quarter moon

Use your notes to answer the following 1. During which two phases of the moon do spring tides occur? 1. During which two phases of the moon do spring tides occur? 2. During which two phases of the moon do neap tides occur? 2. During which two phases of the moon do neap tides occur? 3. What is the tidal range? 3. What is the tidal range? 4. Draw and label a wave using crest, trough, wavelength, and wave height. 4. Draw and label a wave using crest, trough, wavelength, and wave height.