CH 10 Oceanography

Future sea level rise estimates that approximately ________ of existing U.S. coastal wetlands will be lost.

60%

If you built a solid structure perpendicular to the shore, such as a groin, which of the following would occur?

Sand would accumulate on the upcoast side of the structure.

The ________ extends inland from the shore as far as ocean-related features can be found.

coast

The boundary between the shore and the coast is known as the ________.

coastline

Which state contains mangrove swamps?

mangroves

In the figure above, showing a hypothetical groin along a coastline. The triangle extending between the groin and the land represents sediment deposited by the longshore current. In what direction is the longshore current moving? Assume up is north.

north

Narrow currents flowing across the surf zone toward the open ocean are called:

rip currents

The part of the shore that represents the water's edge and migrates back and forth with the tide is known as the ________.

shoreline

For how long will land rebound after a glacier melts?

thousands of years

Larger, high-energy waves scour sand from the berm and create a ________.

wintertime beach

How is an arch formed along a sea coast?

An arch forms when a sea cave breaks through a headland or where two sea caves coalesce as they erode back due to wave action.

Which of the following estuaries forms when sea level rises and floods an existing river valley?

Coastal Plain Estuary

Why does the crust subside slightly on either side of a melting glacier?

Crust under the glacier rises as the ice melts. This allows mantle on either side of the glacier to move to areas under the glacier.

What is the most obvious difference between summertime and wintertime beaches?

During summertime, there is much more sand on the beach

What is the most obvious difference between summertime and wintertime beaches?

During summertime, there is much more sand on the beach.

Which of the following best describes the coastal ocean environment that results in the temperature versus depth graph shown above?

High latitude

What happens to river runoff as it enters the ocean?

It floats on the surface

Compared to a typical estuary, which of the following exhibits the exact opposite circulation pattern?

Laguna Madre

Why does the beach in the video look the way that it does during wintertime?

Large waves move sand offshore onto longshore sand bars and create a rocky beach.

What is the difference between longshore current and longshore drift?

Longshore current refers to the movement of water, longshore drift refers to the movement of sediment.

Why does the crust uplift slightly on either side of a growing glacier?

Mantle under the glacier is pushed aside by sinking crust. This mantle pushes up the crust on either side of the glacier.

Examine the five words and/or phrases and determine the relationship among the majority of words/phrases. Choose the one option that does not fit the pattern

Melting sea ice

In the long term, what do beach drift and longshore current do?

Move sediment parallel to the shoreline

Which of the following occurs during light wave activity?

Much of the swash soaks into the beach

An example of relocation is the movement of Cape Hatteras Lighthouse. Where is the lighthouse located?

North Carolina

Which U.S. coast is considered an emerging shoreline?

Pacific coast

Which of the following beach compartment-to-submarine canyon affiliations is incorrect?

Redondo: Mugu

Which of the following is not a hard stabilization option?

Relocation

What is the salinity profile in areas of the coastal ocean where there is a dry offshore wind?

Salinity is high at the top, decreases rapidly through the halocline, then remains constant to the bottom of the water column.

What is the salinity profile in areas of the coastal ocean where there is river runoff?

Salinity is low at the top, increases rapidly through the halocline, then remains constant to the bottom of the water column.

Why does the beach shown in the video look the way that it does during summertime?

Small waves move sand up the beach face and create a wide, sandy beach.

What process formed the submarine canyons off the Southern California coast?

Some were carved out by rivers when sea level was lower than it is at present, but most form from the erosive action of turbidity currents.

Which of the following estuaries form when faulting or folding of rocks creates a restricted downdropped area into which the sea has flooded?

Tectonic estuary

Judge the following sentence according to the criteria given below: Coastal regions have experienced population increases and increased damage BECAUSE programs like the National Flood Insurance Program have encouraged construction in the unsafe locations they were designed to prevent.

The assertion and the reason are both correct, and the reason is valid

Judge the following sentence according to the criteria given below: The berm is a favorite place of beachgoers BECAUSE it normally consists of dry sand.

The assertion and the reason are both correct, and the reason is valid.

Judge the following sentence according to the criteria given below: Alternatives to hard stabilization have been sought BECAUSE hard stabilization has not been proven to have negative environmental consequences.

The assertion is correct, but the reason is incorrect

What will happen to the crust as a glacier grows?

The crust under the glacier will sink into the mantle.

Which of the following occurs when seafloor spreading rates increase?

There is a rise in sea level

How do engineers decrease the amount of erosion caused by a groin?

They build more groins and place them parallel to each other along the beach.

Beach joggers looking for the most compacted and smooth sand surface prefer to run on the __________.

beach face

Large deposits of sediment at the mouths of rivers are called:

deltas

What type of feature is a barrier island?

depositional

What are groins typically composed of?

large blocks of rock and concrete

In terms of erosion protection from wave action, seawalls:

lead to erosion of sediment on their seaward sides.

Which of the following processes is responsible for the movement of sand down the beach?

longshore transport

In the Southern Hemisphere, the coastal geostrophic current curves ________ on the western coast.

southward

The longshore current generally flows which direction along both the Atlantic and Pacific Coasts of the United States?

southward

What are submarine canyons?

steep-sided valleys cut into the continental slope

Normally, beaches have the greatest amount of sand on the berm near the end of __________.

summer

The Pacific coast, excluding Alaska, has the lowest average erosion rate in the United States, despite significant beach starvation and localized erosion. Which of the following factors accounts for this low average?

tectonic emergence

An estuary produced by faulting or folding of rocks that creates a dropped-down section into which a river flows is called a:

tectonic estuary

Most marginal seas result from which of the following?

tectonic events

What is isostasy?

the rising and sinking of Earth's crust relative to the mantle in response to the redistribution of mass on the surface

What is longshore transport?

the transport of sand and other sediment in a zigzag pattern down the beach

What is the longshore current?

water forced by waves to move along the shore

________ are ecosystems in which the water table is close to the surface, so they are typically saturated most of the time.

wetlands

The image above is an example of which of the following?

Summertime beach

Which of the following statements is/are true regarding groins? Choose all that apply.

-Groins are hard-stabilization structures that are always built perpendicular to shore. -Groins increase erosion on the downcurrent side. -Groins slow the movement of sand along the beach

Of the following characteristics or features, which is/are associated with depositional shores? Choose all that apply.

-High sediment supply -The formation of barrier islands -A location near a large delta -A large sand spit -Bay-mouth bars

Of the following statements about the physical characteristics of coastal oceans, which is/are true? Choose all that apply.

-Onshore wind and coastal runoff create geostrophic currents that flow northward along western North America. -In middle-latitude coastal oceans where evaporation is high, a halocline can develop. -In low-latitude areas where there is no mixing, surface water temperatures can be very high. -In high-latitude areas, the coastal ocean is isothermal (has a uniformly low temperature from surface to deeper waters).

What happens to a barrier island as sea level rises? Choose all that apply.

-Structures on the island are at risk due to increased erosion. -Peat deposits are exposed on the ocean beach side of the barrier island.

How do river runoff and dry offshore winds affect the coastal ocean when they are combined? Choose all that apply.

-They increase rates of evaporation. -They increase mixing

How do dry offshore winds affect the coastal ocean? Choose all that apply.

-They increase surface salinity. -They support the formation of a halocline. -They increase rates of evaporation.

Which of the following factors contribute to the direction of longshore current and longshore drift? Choose all that apply.

-angle that waves approach the shore -wave refraction -major offshore storm centers

Where are barrier islands common? Choose all that apply.

-east coast of the United States -Gulf coast of the United States

How long does it take berms to become narrow and rocky after summer has passed?

a few weeks

In which area(s) of a barrier island is peat formed? Choose all that apply

-low salt marsh -high salt marsh

Which of the following is/are part of a beach compartment? Choose all that apply.

-river -beach -submarine canyon

About what percent of the world fishery is obtained within 320 kilometers (200 miles) of shore?

95%

How does a sea stack form?

A stack forms when a sea arch collapses, leaving a vertical column of rock offshore.

What condition would create a weak longshore current?

A wave set approaching head-on to the shore

Sediment is supplied to the coastal zone by:

All of the above are sources of sediment in the coastal zone.

Where does the Davidson Current develop?

Along the coast of Washington and Oregon

Which of the following can help prevent beach starvation?

Beach replenishment

In general, what do beaches look like at the end of winter?

Beaches tend to have a narrow berm and a prominent longshore bar.

In general, what do beaches look like at the end of summer?

Beaches tend to have a wide berm and no longshore bar.

Why does glacial subsidence NOT occur at the exact moment that a glacier forms?

The rate of subsidence is controlled by the rate at which mantle can flow.

How does the tide cycle affect erosion along a sea coast?

The tide cycle causes erosion to occur at different elevations along a sea coast

How would a beach be affected if a wide berm were protected from erosion during winter months?

The wintertime beach would look similar to the summertime beach

How is a cave created in a cliff face along a sea coast?

Wave action erodes areas of weakness in rock in a sea cliff.

How are winter beaches different from summer beaches?

Winter waves are short and high, whereas summer waves are long and shallower.

One major problem associated with the Chesapeake Bay due to increased human pressure is:

an increase in nutrients resulting in more frequent kills of bottom-dwelling or benthic animals

Which way would sediment move if NO beach drift existed?

at an angle to shore

In which area of a barrier island would you expect to find a woodland or forest?

barrier flat

The area of the barrier island complex that would contain thickets and woodlands would be the:

barrier flat

The particle size on a beach:

is related to whatever material is locally available.

________ protect a harbor or bay entrance and usually occurs in pairs

jetties