Oceanology Exam #2

All things being equal, Which holds more dissolved gases: cold seawater or warm seawater?

cold seawater

What major dissolved gases are found in seawater?

Nitrogen (N2), Oxygen (O2), Carbon Dioxide (CO2)

Water that has no dissolved O2 gas is called what?

Anoxie (anaerobic)

What are the average pH value of seawater?

7.5 to 8.4

what is seawater normally?

slightly alkaline/basic

Which dissolved organics/nutrients are often called the “fertilizers of the sea”?

Nitrate (NO3 -2) and phosphate (PO4 -3)

is saltier water more dense than less salty water?

yes

is colder water more dense than warmer water?

yes

What is the halocine?

salinity

What is the thermocline?

temperature

What is the pycnocline?

density

What are Equatorial countercurrent and how do they form?

• 3 of them

• west-flowing equatorial currents push water against the western boundaries of ocean basins

• water piles up + flows backcast due to gravity

• flow between equatorial currents

• best developed in pacific

• worst developed in the Indiana

Which colors of light (red, yellow, green, blue) penetrates to the deepest depths?

Blue

Which color disappears at the shallowest depths?

Red

Abundant dissolved organic materials result in seawater of what color?

Yellowish seawater

Abundant suspended sediment result in seawater of what color?

Brownish seawater

Abundant plankton results in seawater of what color?

Greenish seawater

What conditions are needed to be deep blue colored seawater?

few particles in water

What is the photic zone?

depth to which light penetrates

Do sound waves bend towards or away from areas of low velocity?

Towards

Sound waves can be trapped in a low velocity layer at about 1000 to 1500 m depth - What is the name of this zone?

SOFAR channel

What is albedo?

reflectivity of a planet or moon

What portions of Earth experience net heat gain?

30 N to 35 S

What portions of Earth experience net heat loss?

above 35 N - below 35 S

What are the dominant gases in modern air?

N2, O2, Ar, CO2

Do warm air masses, rise or sink? does a low pressure air or high-pressure air result?

Rise, low-pressure

Do cold air masses, rise or sink? does a low pressure air or high-pressure air result?

Sink, high-pressure

Does warm air hold lots of moisture( water vapor)?

yes

Does cold air hold lots of moisture( water vapor)?

no

On a spinning, tilted earth, wind paths get deflected from their ideal north-south direction by the Coriolis effect. understand the basics of the Coriolis effect

• Moving objects follow curved paths

• actually are straight paths, but Earth moves under the moving objects.

What are Hadley Cells? Where do they occur?

• Warm air rises at equator + releases rain.

• Dry air moves N or S + cool, sinks, returns to equator

• 30 N - equator- 30 S

What are Ferrel Cells? Where do they occur?

• Rising warm air + sinking cool air

• Move like interlocking gears, matching air movement of adjacent cells

• 30 N - 60 N + 30 S - 60 S

What are Polar Cells? Where do they occur?

• rising warm air + sinking cool air

• 60 N - North Pole + 60 S - South Pole

What are sea breezes?

During the day, cool air moves in from ocean, towards the land

What are land breezes?

At night, cool air above land moves out to the sea

Be familiar with the basics or hurricanes

• largest storms on Earth

• summer to fall

• usu. last 5-10 days

• usu. moves from east to west

What is sea ice?

frozen seawater

what are icebergs?

large masses of ice detached from glaciers on land

Do icebergs originate in the sea?

no

What is the first stage of sea ice formation?

• small needles

• hexagonal crystals of the mineral ice, H2O

What is pancake ice?

pieces of ice that get rounded into discs by erosion

Does sea ice have the same salinity as ordinary seawater?

no

How many subtropical gyres exist in modern oceans? Where are they located?

• 2

• North Hemisphere + South Hemisphere

How many currents does each subtropical gyre have?

4

Are western boundary currents warm + fast moving or cool/cold and slow moving?

Warm + fast moving

What is an equatorial current?

flow to the west along equator

What is an Ekman Spiral? How do they form?

• Surface waters don’t move with wind direction

• Coriolis effect

What is upwelling?

upward movement of cold, nutrient-rich water to the surface

What is downwelling?

downwards movement of surface water to the deep

What is coastal upwelling?

Winds + Ekman transport move water away from the coast

What is coastal downwelling?

Winds + Ekman transport move water towards the coast

What is the West Wind Drift?

Clockwise current going around Antarctic

What is the Sargasso Sea?

Rotation center of the North Atlantic subtropical gyre

What is El Niño?

Warm phase

What is La Niña

Cold phase

In the Indian Ocean, do changing monsoon seasons every 6 months change ocean currents from 2 large loops of water to 1 large loop of water

yes but it depends on the season

Most waves are continuously generated by what?

winds

What are ocean waves?

waves at the air-water interface caused by winds

What are atmospheric waves?

Waves at the air-air interface

What are internal waves?

waves at the water-water interface

What are longitudinal waves?

Waves that move by compression + decompression

What are orbital waves?

particles move in circular orbits

What is crest?

highest part of a wave

What is trough?

lowest part of a wave

What is the still water level?

halfway marks between crest + trough

What is wave height (H)?

vertical distance between crest + trough

What is wavelength (L)?

crest-to-crest

What is deep water waves? Do they interfere with the seafloor?

• Water depth is > than wave base

• no

What is shallow water waves? Do they interfere with the seafloor?

• Water depth is < than water base

• yes

What is sea?

choppy, irregular waves

what is swell?

uniform, long-crested, symmetrical waves

What is surf?

zone of breaking waves

Spilling breakers

flat beaches

plunging breakers

somewhat steep beaches

surging breakers

steep beaches

which is most common type of breaking wave?

spilling breakers

what type of breaking wave has a curling crest of water over an air pocket?

plunging breakers

what type of breaking wave develops at steep beaches and shore face?

surging breakers

What is wave refraction?

in shallow water, waves bend so that crest are parallel

Does wave energy get concentrated at headlands?

yes

Does wave energy get spread out in embayments?

yes

What is wave reflection?

Waves encounters + bounces away from a vertical barrier

How does stationary waves form?

2 waves with the same L move in opposite directions; no net movement

What are tsunamis?

Large destructive waves that occasionally arrives at the coastline

What kinds of real-life geologic events are known to generate tsunamis?

• earthquakes

• volcanic eruptions

• underwater sediment slides

What happens at the shoreline before a tsunami hits?

sudden drop in sea level

What two extraterrestrial bodies cause the tides?

sun + moon

What is high tides?

maximum elevation of water

What is low tides?

minimum elevation of water

What is flood ride?

tides coming in

What is an ebb tide?

tides going out

The highest tidal range on modern Earth occurs at what locality?

Bay of Fundy, Nova Scotia (SE Canada)

What is the highest tidal range on Earth, in meters

17m

What is tidal bore?

true tidal wave

How much more influence does the Moon have over Earth’s tides than the Sun?

two times

What is centripetal force (gravitational pull)?

keeps the moon in orbit

What is inertia (centrifugal force)?

keeps the Earth + Moon apart

How long is a full trial cycle? Is it the same as one Earth day/ solar day? (=24 hours)?

• 24 hours, 50 mins

• No

What is a spring tide?

When sun, moon, and earth are aligned, solar tide is added to lunar tide

What is a neap tide?

When sun, moon, and earth are at right angles, solar tides + lunar tides partially cancel each other out