BJU Earth Science, Ch. 14

moon

has the greatest influence over the tides

2 lows 2 highs

how many tides do most coasts experience in a typical 24 hour period

What causes the high tides that occur twice a month?

the sun, moon, and earth being arranged in a straight line

Antarctic Circumpolar Current

includes the southern portions of the Pacific, Atlantic, and Indian Ocean gyres. Also transfers surface and subsurface currents between these main basins as it flows past Africa, South America, and Australia.

Canary Current

the major warm current located in the West Atlantic Ocean

Ekman spiral

combines the effects of the Coriolis effect, current speed, and water depth to produce the direction of a current

plankton, European eels, humpback whales, blue sharks, sea turtle, sea birds

sea life that is thought to take advantage of ocean currents in their efforts to move about

higher than outside the gyre

in the center of a ocean gyre, the sea level is usually ____.

more oxygen but less nutrients

water that is forced down by downwelling typically has _____ than surrounding waters.

prevailing winds

has the least effect on subsurface currents

2 things applying to thermohaline currents

density currents
subsurface currents

wave base

the deepest depth below the ocean's surface that is affected by the wave's passage

wave period

most directly related to wave speed

rip currents

cause the greatest amount a drownings per year
a strong, narrow surface current that carries water from the shore to the sea

neap tides

occur twice each month; lower-than-usual tides

Great Pacific Garbage Patch

the result of man's carelessness and a strong oceanic gyre

turbidity current

type of density current that carries a great amount of sediment and acts like an underwater mudslide

wavelength

the horizontal distance from the crest of one wave to the crest of the next wave

fetch

distance that wind blows over the water's surface in one direction

stack

a mass of rock that has been cut off from the mainland by erosion

Why is upwelling often associated with very productive fisheries?

Upwelling pulls up nutrients that support phytoplankton, the basis of the marine food chain

Why is it inaccurate to call a tsunami wave a tidal wave?

Tsunami waves are caused by large earthquakes. The regular changes in sea levels caused by the gravitational pull of the sun and the moon are true tidal waves.

Why are groins sometimes constructed along coastlines?

Groins disrupt longshore currents, thus reducing beach erosion

breaker

an unstable wave whose crest is falling forward

gyre

a circular flow of currents within an ocean basin

hook

a pit with a harp bend

longshore current

a current resulting from waves breaking at an angle to the shore

spring

a higher-than-usual tide occurring twice a month

tides

the alternating rise and fall of local sea level

tombolo

a wave deposit that connects an island or a stack with the mainland

trough

the lowest part of a wave

upwelling

cold water rising to the surface

power plants

designed to harness the power of tidal changes
are fairly small

currents

are affected by the rotation of the earth

Cold ocean currents

along a coast can dry the air so much that a desert forms

longest waves

greatest speed

List at least 3 things besides the position of the sun and moon that can affect the height and times of the tides.

1. the shape of the coastline
2. width of the continental shelf
3. the size and depth of the ocean basin
4. position of the moon relative to the Equator
5. a hurricane can also push water forward, causing dangerously high tides, especially if it occurs du

Describe density currents and the major factors that cause them to develop and flow

Water that is higher in salinity is also denser, causing it to sink below less dense water. Cooler water is also denser than warmer water. AS a result, these factors cause the coldest, densest water to move to the sea floor where gravity causes it to foll