Study Guide For The Physical Oceanography Unit Test

Test is on 2/20/26

where did the water to form the oceans come from

water trapped inside of the earth’s mantle

how did the oceans become salty and what happens to salinity over time

weathering, erosion, acidic rain, and salinity stays stable

what are the two main ions in seawater

sodium & chloride

how does seawater evaporate

solar energy causes molecules to break out of their liquid state

what is the pressure of the atmosphere at sea level

14.7 psi

how deep does a diver need to go in meters to add another atmosphere of pressure

10 meters

name the three major layers of the ocean

surface mixed zone, transition zone, deep zone

what happens to water temperature in the thermocline layer

water temperature drops rapidly with increasing depth

currents that move in a large circular motion are called

gyres

what is the main cause of surface waves

wind blowing across the surface

what are the names of the 5 major oceans

pacific north/south, atlantic north/south, indian, southern, arctic

at what location is the new ocean floor being created

the mid ocean ridge

which ocean is the largest

pacific north/south

which hemisphere has the most water

the southern hemisphere

put the oceans in order from smallest to largest

arctic, southern, indian, atlantic n/s, pacific n/s

what is the deepest part of the ocean named

the mariana trench

what makes earth so unique with regards to properties of water

the surface temperature allows for water to exist in all three states (solid, liquid, & gas)

describe the heat capacity of water

gain & releases heat slowly

how does the heat capacity of water affect the land near a large body of water

can moderate the temperature of the coast nearby

how does water evaporate off of the oceans

water molecules steal heat from other molecules & the bonds break from solar energy

what is the freezing point of salt water and what happens to it (both volume and salinity)

28.4 degrees farenheit, increases the salinity of the surrounding water, turns into ice, the remaining salt turns into liquid

what is an rov

remotely operated vehicle

what type of device is used for measuring depth in the ocean

remotely operated vehicle (rov)

name an area of the ocean where salinity is high and an area where salinity is low at the surface

red sea (high), arctic (low)

what causes salinity to increase

when salts occur, driven by natural processes such as evaporation

why does the ocean appear bluish-green

light absorption

what are the two types of microscopic organisms that form the basis or the oceanic food chain

phytoplankton & zooplankton

thermocline graph

why is a thermocline nearly vertical at the poles

polar surface waters are consistently cold

ideal wave chart

wave period

time for 2 crests to pass a fixed point (T) seconds

wave speed

celerity, the formula is C: wavelength/time (meters/sec.)

wave steepness

height/wavelength

chop

short period (back bays)

swell

long period (boat rolls; seasickness)

what 3 things determine the size of wind generated waves

wind speed, wind duration (length of time that the wind blows), “fetch” extent of open water across which the wind can blow

rogue waves

causes: energy that gets concentrated into one huge wall of water.

where do they occur: at the agulhas current of south africa & the gulf stream in the north atlantic, where strong, opposing currents meet.

frequency: many times daily

tsunamis

causes: underwater earthquakes/volcanoes

description at sea: long, fast moving waves

description as it comes ashore: a fast moving turbulent wall of water that can get up to 100 feet

warning signs: rapid, unusual rise or fall in the water level

sumatra tsunami

when: 2004

what ocean: indian ocean

number of casualities; 220-230,000

tidal range

vertical distance between high & low tides

tidal bulge

bulge of water on the opposite sides of the earth

terms for high tide

rising, incoming tide, flow

terms for low tide

receding, outgoing tide, ebb

slack tide

when the vertical movement stops

spring tide diagram + impact on tides

neap tide diagram + impact on tides

apogee moon

moon is closer to earth & causes very high tides

perigee moon

moon is farthest from the earth & causes very low tides

diurnal tide

one high, one low per day, can be found along parts of the gulf of mexico & asia

semi-diurnal tide

two high, two low per day, can be found along the atlantic coasts of north america & europe

mixed tide

two high, two low per day, height will vary, found along the pacific coast

what is the length of a lunar day

29.53 earth days

how often does the moon orbit the earth

once every 27.3 days

in regards to the water column, where does warm water move? where does cold water move?

warm water moves horizontally across the surface from the tropics towards the poles

cold water moves towards the bottom of the water column

what causes currents

wind

earth’s rotation

density changes

longshore current

flows parallel to the shore & moves sediment

gyre

large system of rotating ocean currents

eddy

circulating water that gets pinched off from the current

upwelling

where winds push surface water away, causing deep, cold, nutrient-rich water to rise & replace it

how does the coriolis effect move water in the northern hemisphere

to the right

how does the coriolis effect move water in the southern hemisphere

to the left

what is the gulf stream, & how does it start the global conveyor belt of deep ocean circulation

powerful, warm ocean current in the atlantic that starts from the gulf of mexico

drives wind & ocean currents, carries warm, salty water, & benefits animals.

what should you do if you get caught in a rip current

don’t fight it, swim parallel to the shore to get out of the current

the three types of breaking waves

spilling breaker: gently-sloped beach

plunging breaker: moderately-sloped beach

surging breaker: steeply-sloped beach

how and why do currents move water around the ocean & their effect on coastal cities (hot vs. cold)

warm currents (the gulf stream) raise coastal temperatures

cold currents (the california current) creates cooler, foggy conditions

currents are driven by the coriolis effect

the dangerous water that flipped the sailboat in the 7 deadly seas video was located off of the tip of what area, & is called the cape of…

the “graveyard of ships”

the southern tip of tierra del fuego, chile

cape horn

what happened to the Trieste on it’s dive to the bottom of the Challenger Deep?

intense pressure cracked an outer plexiglass window, but the vessel still remained functional, so they went on to spend 20 minutes on the seabed

what was used to help the trieste float, & why did they have to use it

approx. 34,000 gallons of gasoline in a thin metal float to provide buoyancy

where is the gulf stream located

originates in the gulf of mexico

where is the agulhas current located

the southwest indian ocean

where is the california current located

southward along the western coast of north america

what causes up & downwelling

the coriolis effect

what is the benefit of upwelling

brings cold, nutrient-rich water to the surface, & fuel the base of the ecosystem

how big is the great pacific garbage patch

617-620,000 square miles

what would cause the highest possible high tide

high tides are caused by the alignment of the sun, moon, & earth (spring tides)

what would cause the lowest possible low tide

low tides are caused when the sun & moon are at right angles, which in turn, causes their gravitational forces to counteract