exam 3 Flashcards
The vertical distance between the wave crest and the wave trough is the
Quiz 3-1
wave height
A deep-water wave is a wave that is in water
Quiz 3-1
greater than one half the wavelength.
When you go to the beach, most of the waves you see are caused by
Quiz 3-1
the wind.
Waves coming on to the shore are gentle spilling breakers when
Quiz 3-1
the shore shallows gradually over a long distance.
The distance a continuous wind blows across uninterrupted water is the __________.
Quiz 3-1
fetch.
The open ocean always has gentle 1-2 m (≈3-6 ft) waves, called ________
Quiz 3-1
swells
Why are most tsunamis found in the Pacific Ocean?
Quiz 3-2
It is the ocean with the most subduction zones
The most likely place for a tsunamis to start is
Quiz 3-2
The Subduction Zone
Tsunamis are
Quiz 3-2
caused by underwater earthquakes.
You own a nice 50-foot yacht in Hilo, Hawaii and you hear a tsunamis is coming in 8 hours. For the best result (save yourself first, the boat if possible), you should:
Quiz 3-2
Immediately cast off and sail out to deep water and wait for the all-clear announcement
A tsunamis with a wavelength of 200 km is a deep water wave
Quiz 3-2
Never, tsunamis are shallow-water waves.
A Tsunamis Early Warning System doesn’t work when
Quiz 3-2
the coast is very close to the source of the tsunamis
Diurnal tides have a high tide
Quiz 3-3
once a day.
The time with no tide currents is called:
Quiz 3-3
slack water
Flood tide refers to
Quiz 3-3
the tide current rising toward the high water mark.
In an area with semidiurnal tides, sea level (zero water depth) is equal to the water level at
Quiz 3-3
mean low tide.
A minus tide is a tide that
Quiz 3-3
is lower than the average low tide.
The tide range refers to
Quiz 3-3
the elevation difference between high tide and low tide.
Equilibrium moon-tides have two wave crests on opposite sides of the earth, one pulled by the force of _______________, and the other by the _______________ force.
Quiz 3-4
gravity, centrifugal
High tides are highest and low tides are lowest (largest tide range) during _______.
Quiz 3-4
spring tides
Destructive interference occurs when the _________ of one wave intersects the __________ of another wave.
Quiz 3-4
trough, crest
Tides that only occur at the time of the first quarter moon and the last quarter moon are
Quiz 3-4
neap tides.
You come to the beach to find high tide at 10:00 am. About what time tomorrow will you find high tide again?
Quiz 3-4
10:50 am
You want to calculate the height of the tide on Thursday in Los Angeles harbor. You will use the
Quiz 3-4
Dynamic Tide Model.
An emergent coast can be caused by
Quiz 3-5
all of these.
A long, narrow island made of sand deposited parallel to the shore is a
Quiz 3-5
barrier island.
A short beach contained between two rocky headlands:
Quiz 3-5
pocket beach
A __________________ forms when sea level rises and floods the lower parts of a river.
Quiz 3-5
drowned river valley.
Sea cliffs and pocket beaches are characteristic of a(n) _______________ coast.
Quiz 3-5
emergent
Pick the submergent coast:
Quiz 3-5
all of the above are submergent coasts
Starting on land and moving seaward, the parts of a beach profile are (in order)
Quiz 3-6
backshore – berm – foreshore – offshore
You spend a week on a sandy beach this summer and then come back next year. The sand on the beach
Quiz 3-6
has been completely replaced by longshore transport by waves.
A low sandy tongue of land extending out from the shore is called a
Quiz 3-6
sand spit.
A rip current is
Quiz 3-6
a fast current that takes water away from the beach.
Sand is removed from the coastal circulation cell by
Quiz 3-6
submarine canyons.
You visit a beach in New York and find a sand spit that points to the north. What is the main direction of longshore transport in this location?
Quiz 3-6
to the north
Breakwaters that produce a wave-protected environment in a region of longshore drift cause __________ in the area they protect.
Quiz 3-7
deposition
In an area of north-to-south longshore drift, building a groin leads to ________ on the north side and __________ on the south side of the groin.
Quiz 3-7
deposition, erosion
A short man-made barrier, designed to trap sand and make a wider beach:
Quiz 3-7
groin
When a harbor is created by building a breakwater, why does it usually need to be continuously dredged?
Quiz 3-7
ongshore transport of sand fills in the harbor.
Building a seawall to protect a building from erosion can cause
Quiz 3-7
erosion of the beach in front of the wall.
_________________ is when sand is brought by man in to rebuild an eroding beach.
Quiz 3-7
Beach replenishment
What is an estuary?
Quiz 3-8
a portion of the ocean that is semi-isolated and diluted by fresh water.
Towns on estuaries often grow into cities. Reasons include all of these EXCEPT:
Quiz 3-8
High wave energy makes good beaches for tourists.
The salinity profile of an estuary is controlled by
Quiz 3-8
size of the river
water depth of the estuary
tide range
A small creek entering a shallow bay will probably produce
Quiz 3-8
a well-mixed estuary.
An estuary where fresh water flows out over salt water for some distance before mixing is a ____________ estuary.
Quiz 3-8
salt wedge
Calculations of flushing times assume that none of the outflowing water is carried back into the estuary. If this assumption is not correct, the actual flushing time is __________ the calculated flushing time.
Quiz 3-8
greater than
Coastal wetlands are important
Quiz 3-9
as both nursery and habitat areas for many birds and fish.
Which of the following sources of pollution is considered a point source for pollution?
Quiz 3-9
A and B.
Dead zones with no oxygen in Chesapeake Bay are caused by
Quiz 3-9
excessive nutrients leading to algal blooms that later decay.
Why is it difficult to correct the pollution problem of excessive nutrients in Chesapeake Bay?
Quiz 3-9
The pollution is coming from thousands of small sources difficult to identify or correct.
Construction sites with poor environmental practices lead to ___________ in Chesapeake Bay.
Quiz 3-9
excessive sediments
The most likely source today of toxic metals (e.g. lead or mercury) in Chesapeake Bay today is
Quiz 3-9
an old closed manufacturing plant.
Oil booms are
Quiz 3-10
floating tubes used to contain floating oil spills.
The greatest threat to global coastal waters from oil pollution is
Quiz 3-10
oil washed into the ocean from oil spilled everyday by cars on streets and parking lots.
What does an oil dispersant do?
Quiz 3-10
Breaks up an oil spill so it won’t wash ashore.
A vessel for collecting oil floating on the surface of the water:
Quiz 3-10
oil skimmer
Pick the item which is NOT made from hydrocarbons:
Quiz 3-10
All of the above are made from hydrocarbons
Which phrase best describes modern cleanup technology for oil spills?
Quiz 3-10
moderately successful in quiet water
crest
L3-1 Defintions
the high part of a wave
trough
L3-1 Defintions
low part of the wave
wavelength
L3-1 Defintions
the horizontal distance between two wave crests or between two wave troughs (both are the same)
amplitude
wave height
L3-1 Defintions
vertical distance between the crest and trough
also equal to 1/2 the wave height
wave period
L3-1 Defintions
- time needed for two successive wave crests to pass
- measured with a stopwatch.
- speed=distance(miles) per time(hour)
how long it takes for one wavelength to pass(usually seconds)
wave orbit
L3-1 Defintions
water does move as the wave passes but ends up in about the same place after the wave has gone by.
out in the open ocean the water moves in a circular orbit as the wave goes by
deep-water wave
L3-1 Defintions
wave that does not reach the bottom
wave in water deeper that one-half the wavelength
need to know both the water depth and wavelength to determine whether or not a wave is a deep-water wave
orbital waves.
shallow-water wave
L3-1 Defintions
When the water is shallower than 1/20th the wavelength, it is considered a shallow-water wave and the water depth is the most important factor.
So a shallow-water wave is any wave in water less than 1/20th the wavelength.
Like the definition of a deep-water wave, both water depth and wavelength are needed to determine if a wave is a shallow-water wave.
A wave on the surface of the water whose
wavelength is at least 20 times water depth. The bottom affects the orbit of water particles, and speed is determined by water depth
plunging breaker
L3-1 Defintions
The plunging breakers occur where the water goes from deep to shallow over a short distance.
spilling breaker
L3-1 Defintions
produced spilling breakers in a shallow bay where the sea floor shallowed over a long distance
refraction
L3-1 Defintions
Wave refraction means most waves approach the beach at relatively small angles, regardless of where the waves come from. However, the process doesn’t have a chance to completely straighten the waves so they almost never come in perfectly parallel to the beach.
Wave refraction results when one part of a wave (off the points of land here) slows down while the rest of the wave, still a deep-water wave, does not.
On an irregular coast, the result is a concentration of wave energy on the headland (which sticks out) and dispersal of energy in the quiet pocket beaches (in between the headlands).
wind speed
L3-1 Defintions
The stronger the wind, the more force it can apply to the water. Therefore, faster winds push up larger waves.
wind duration
L3-1 Defintions
The wind duration refers to how long (in time) the wind blows.
Is it just a single gust of wind? Then the waves will be fairly small, even if the wind is very strong. If the wind blows for days, then waves can be pushed higher and higher until large waves result.
fetch
L3-1 Defintions
The fetch refers to the continuous distance the wind blows.
Since the waves are constantly moving, the wind must keep pushing as it moves to make a big wave. If the wave runs into land too soon, then a large wave will never be built.
So small bays or lakes won’t ever get really large waves because the fetch is too short. A really large fetch, like the Pacific Ocean, allows really large waves to be built.
storm waves
L3-1 Defintions
Storms at sea produce most of the waves that come breaking against the shore. Storms have strong winds (1. wind speed), they blow for several days (2. wind duration), and they are very large, traveling across hundreds of miles (3. fetch).
A given wind speed, however, has a maximum wave height that it can build because the energy needed to make a wave bigger increases as wave height increases.
Given sufficient fetch and time, a 10 knot wind (a light breeze, knot equals nautical miles per hour, 1 nautical mile is about 1.1 miles) will make waves with an average height of 1.2 m
but a 30 knot wind (a small storm) will make waves that average 5.8 m
All of the really large waves (greater than 4 m or 13 ft) start during storms.
ocean swells
L3-1 Defintions
By contrast, smaller-size waves, like the ever present swells (1 m tall), however, can also start with the trade winds, particularly in the Pacific Ocean.
The trade winds are not terribly strong winds, but they blow for months and years at a time across thousands of miles of open ocean.
This extreme duration and fetch compensates for the lower wind speed and generates some of the open ocean waves known as swells.
Storm waves get smaller as they spread out from the storm and cross the vast expanse of ocean; this is another way to make swells.
Know the anatomy of a wave. Be able to label the parts of a wave.
L3-1 Concepts
Crest (high point)
Trough (low point)
Wavelength (distance between two trough)
Wave height (vertical distance between crest/trough)
Wave period = time it takes one wavelength to pass
What is the orbit of a wave?
How does the orbit of a deep-water wave differ from that of a shallow-water wave?
L3-1 Concepts
When the water depth first becomes less than one-half the wavelength, the wave “feels the bottom” and the orbits are compressed into flattened ovals (properly ellipses), sort of like a beach ball with a big kid sitting on it.
The shape of the orbit, therefore, is an easy way to tell whether a wave is a deep-water wave: if the orbit is a round circle, it is a deep-water wave; otherwise it is either an intermediate water wave or a shallow-water wave.
What are the differences between a deep-water wave and a shallow-water wave?
L3-1 Concepts
A deep-water wave is a wave that does not reach to the bottom. Since, the orbit extends to a depth of one-half the wavelength, a deep-water wave is a wave in water deeper than one-half the wavelength.
A deep-water wave does not, therefore, require deep water–just water deeper than one-half the wavelength
If they do not touch the sea floor, then the wave proceeds without changing.
Once the wave orbits encounter the sea floor, the free motion of the wave is interfered with and the wave starts to change.
When the water depth first becomes less than one-half the wavelength, the wave “feels the bottom” and the orbits are compressed into flattened ovals (properly ellipses)
if the orbit is a round circle, it is a deep-water wave; otherwise it is either an intermediate water wave or a shallow-water wave.
While the properties of a deep water wave are dictated by the generating force (usually wind; see below), as it changes by interaction with the bottom, the water depth becomes increasingly important. When the water is shallower than 1/20th the wavelength, it is considered a shallow-water wave and the water depth is the most important factor.
So a shallow-water wave is any wave in water less than 1/20th the wavelength
What happens when a deep-water wave starts to feel the bottom?
Explain why the wave slows, the wavelength gets shorter, and the wave height gets taller.
L3-1 Concepts
When the water depth first becomes less than one-half the wavelength, the wave “feels the bottom” and the orbits are compressed into flattened ovals (properly ellipses)
Because the orbit is not free to move, the wave is forced to slow down. Remember that the speed = wavelength / period and that the period is constant and cannot change. Therefore, when a wave slows down, the wavelength must also decrease to keep this equation true.
And this is what we observe when we look at waves coming onto the shore. They bunch together with the wavelengths getting steadily shorter as the waves “feel” more of the bottom.
However, the energy of the wave doesn’t change much, so the same amount of energy is squished into a shorter wavelength, which makes the wave height get larger.
How does the shape of the seafloor control whether a wave coming into shore and breaking will be a plunging breaker or a spilling breaker?
L3-1 Concepts
As the wave height increases, eventually the wave will become too steep and the wave will break, with the crest curling over and crashing on the adjacent trough.
The base of the wave is slowing more than the top of the wave because it is the base that is “feeling” the bottom. Therefore, the high point (the crest) is going faster and outruns the rest of the wave. Sometimes the wave curls over in a spectacular plunging or curling breaker
Most waves are generated by the winds. Explain how wind speed, wind duration, and fetch contribute to the size of a wave.
L3-1 Concepts
In general, the more wind that pushes at the water the bigger the wave will get (meaning higher).
Wind speed: The stronger the wind, the more force it can apply to the water. Therefore, faster winds push up larger waves.
The wind duration refers to how long (in time) the wind blows. Is it just a single gust of wind? Then the waves will be fairly small, even if the wind is very strong. If the wind blows for days, then waves can be pushed higher and higher until large waves result.
The fetch refers to the continuous distance the wind blows. Since the waves are constantly moving, the wind must keep pushing as it moves to make a big wave. If the wave runs into land too soon, then a large wave will never be built. So small bays or lakes won’t ever get really large waves because the fetch is too short. A really large fetch, like the Pacific Ocean, allows really large waves to be built.
tsunami
L3-2 Definitions
is an enormous wave that forms when the sea floor somehow moves, displacing the water above it
vast majority occur in the Pacific ocean
shallow-water wave (Tsunami)
L3-2 Definitions
Generally, the sea floor doesn’t actually move very far, so the tsunamis waves start with low wave height, only 1 or 2 m.
The wavelength, however, is very large, somewhere between 100 and 200 km (60-120 miles).
Because of this long wavelength, a tsunamis is a shallow-water wave even out over the abyssal plains.
(Remember, a shallow-water wave is a wave in water shallower than 1/20th the wavelength. 1/20th of 100 km = 5 km (or 5000 m) and the average depth of the Pacific Ocean is only 4028 m.)
subduction zone
L3-2 Definitions
The most common location for a large underwater earthquake is in a subduction zone, because mid-oceanic ridges are too hot and soft to store enough energy for a large earthquake.
The old, cold plates going down subduction zones, on the other hand, can store a lot of energy before they break and cause an earthquake. In addition, the kind of movement on a subduction zone (convergent) tends to move the sea floor up or down more than the side-by-side motion of a spreading center.
Just about every subduction zone in the Pacific has generated a tsunamis in historic times. Japan is more prone to these waves because it sits nearly on top of three subduction zones and faces even more of them across the expanse of the Pacific Ocean.
What is a tsunami? How does it start?
Why are most tsunamis found in the Pacific Ocean? What is it about subduction zones that make tsunamis more common there
L3-2 Concepts
the Pacific Ocean is ringed by subduction zones while the Indian and Atlantic Oceans have very few
tsunamis also known as seismic sea waves, are a series of enormous waves created by an underwater disturbance such as an earthquake, landslide, volcanic eruption, or meteorite. A tsunami can move hundreds of miles per hour in the open ocean and smash into land with waves as high as 100 feet or more.
in a subduction zone, an oceanic plate dives beneath another plate the contact between these two plates doesn’t slide smoothly causing the upper plate to distort. Eventually the distortion is so great that the upper plate breaks free, causing an earthquake and moving the sea floor upward
When the sea floor moves, the entire water column above it also moves–the disturbed water moves away from the starting point as rings of waves–and these waves will travel until they are stopped by land, even if that is thousands of miles across the Pacific Ocean.
Generally, the sea floor doesn’t actually move very far, so the tsunamis waves start with low wave height, only 1 or 2 m. The wavelength, however, is very large, somewhere between 100 and 200 km (60-120 miles).
So the energy of a tsunamis is much greater than that of a wind-driven wave because it involves the entire ocean, not just the surface layer. Tsunamis have a period of 10 to 20 minutes and in the open ocean travel at around 760 kph (480 mph)!
Why is a tsunamis a shallow-water wave even in the middle of the Pacific Ocean? (Review the definition of a shallow-water wave.)
L3-2 Concepts
Generally, the sea floor doesn’t actually move very far, so the tsunamis waves start with low wave height, only 1 or 2 m. The wavelength, however, is very large, somewhere between 100 and 200 km (60-120 miles). Because of this long wavelength, a tsunamis is a shallow-water wave even out over the abyssal plains.
(Remember, a shallow-water wave is a wave in water shallower than 1/20th the wavelength. 1/20th of 100 km = 5 km (or 5000 m) and the average depth of the Pacific Ocean is only 4028 m.)
So the energy of a tsunamis is much greater than that of a wind-driven wave because it involves the entire ocean, not just the surface layer. Tsunamis have a period of 10 to 20 minutes and in the open ocean travel at around 760 kph (480 mph)!. And, just like that rock in a pond, there are several waves, not just one. Often the second, or even third, wave is the largest. Also, as the wave travels, it spreads out and gets smaller. The worst damage occurs to the closest land.
diurnal tide
L3-3 Definitions
Some coastal areas have one high tide and one low tide per day, a little over 12 hours apart.
These are called diurnal tides (from the Latin word for “day”) because the complete cycle takes one day to complete
semidiurnal tide
L3-3 Definitions
More commonly, there are two high tides per day and two low tides.
When the two high tides are about the same height (and the two low tides are about the same height), the tides are called semidiurnal tides because there are two complete tide cycles per day
mixed tide
(mixed semidiurnal tide)
L3-3 Definitions
In many areas, the two high tides and the two low tides are of different elevations.
Where the difference in elevation between successive high (or low) tides is fairly large,
The word mixed, therefore, is used to indicate the fact that the high tides are of mixed height (and the lows, too).
flood tide
L3-3 Definitions
a rising tide, which occurs as low tide rises to high tide. Signifies a strong current, generally toward land.
ebb tide
L3-3 Definitions
A falling tide, which occurs as high tide falls to low tide. Signifies a strong current, generally away from land.
slack tide
L3-3 Definitions
the brief time when there are no tide currents. Coincides with either a high tide or a low tide.
tidal current
L3-3 Definitions
Movement of water toward and away from the coast due to the rise and fall of the tides
high water
L3-3 Definitions
high water level between two lower water levels.
For mixed semidiurnal tides, we distinguish between higher high tide and lower high tide.
low water
L3-3 Definitions
low water level between two higher water levels
For mixed semidiurnal tides, we distinguish between higher low tide and lower low tide.
sea level
L3-3 Definitions
zero elevation
defined as Mean low tide (for areas with diurnal/semidiurnal tides)
or Mean Low-Low tide (for areas with mixed tides)
minus tide
L3-3 Definitions
A low tide that is lower than the average.
Since tides are measured relative to sea level, and sea level equals the average low tide, any tide below average has a negative elevation.
For example -1.2 ft. Hence the name, “minus tide”
equilibrium tides
L3-3 Definitions
The equilibrium tide model looks at the orbital relationship between the earth, the moon, and the sun as the earth turns on its axis.
the force of gravity combined with the earth-moon coupled system creating a centrifugal force resulting in bulges under which the earth rotates
dynamic tides
L3-3 Definitions
factors back in all the complexity left out of equilibrium tides, and so that it closely matches the real world–these are things like the shape and size of the ocean or inlet, the Coriolis Effect, the role of friction, the path the water takes moving in and out of coastal areas, and so on.
gravity
L3-3 Definitions
The tides result from the gravity and centrifugal forces of the moon and sun pulling the water of the ocean into a large wave with two crests, one lined up under the moon and the other on the opposite side of the earth from the moon.
The earth spins under this wave, one rotation every 24 hours, so the water rises and falls as we spin under first the crest and then under the trough of the tide wave
centrifugal force
L3-3 Definitions
The tides result from the gravity and centrifugal forces of the moon and sun pulling the water of the ocean into a large wave with two crests, one lined up under the moon and the other on the opposite side of the earth from the moon.
The earth spins under this wave, one rotation every 24 hours, so the water rises and falls as we spin under first the crest and then under the trough of the tide wave
neap tides
L3-3 Definitions
The smaller tide range that occurs between spring tides are called neap tides
which occur at the first quarter moon and the last quarter moon
spring tides
L3-3 Definitions
When the tide range is at the maximum, the tides are called spring tides.
This occurs every two weeks, about the times of a new moon and a full moon
beach
L3-6 Definitions
is a deposit of the shore area
backshore
L3-6 Definitions
is above the high tide shoreline and is covered with water only during storms
foreshore
L3-6 Definitions
is the portion exposed at low tide and submerged at high tide
berm
L3-6 Definitions
is the dry, gently sloping region at the door of the costal cliff or dunes
breakwater
L3-7 Definitions
A structure protecting a nearshore area from breaking waves, one was constructed in Santa Barbara, Cali
jetty
L3-7 Definitions
A structure that projects into the water and protects the shore, similarly built to a groin
groin
L3-7 Definitions
a type of hard stabilization, built perpendicular to a coastline and are specifically designed to trap sand moving along the coast in longshore transport
seawall
L3-7 Definitions
A barrier constructed to prevent waves from reaching the area behind the wall. Its purpose is to defend property from the force of breaking waves.
beach replenishment
L3-7 Definitions
when sand is added to the beach to replace lost sediment
What happens to longshore transport when a breakwater is built? Where is the sand deposited for a simple breakwater? How about a breakwater that is attached to the shore?
L3-7 Concepts
It blocks the waves, stopping longshore transport. this causes the sand to build up, requiring dredging
What is the difference between a jetty and groin? What happens to longshore transport when a jetty or groin is built? Be able to predict where sand will be deposited versus eroded.
L3-7 Concepts
Jetty- 90 degrees from shore, deliberately stops longshore transport and builds a big beach but erodes the latter side
Groin- Short and 90 degrees from shore, built to block the sand from filling the harbor and causes erosion down the beach
Why does building a seawall usually lead to complete erosion of the beach? Consider plunging versus spilling breakers in your answer.
L3-7 Concepts
As the crest of a tsunami wave builds, it draws into itself water from both sides of the crest. You can see the same thing happen anytime a wave comes ashore: first the water recedes a bit, pulled into the rising crest, and then the crest comes crashing down.
Open ocean is safe because tsunamis are undetectable there, being only 1-2 m
What is beach replenishment and why is it only a temporary solution? Why do people still do it, even knowing it will have to be repeated?
L3-7 Concepts
Beach replenishment is the manual effort of bringing in sand to make nice, big beaches. However, when winter comes the large storm and winter waves erode the beach, taking away the sand. This is repeated anyway because of tourism and keeping the local economy In motion
estuary
L3-8 Definitions
drowned river valley
freshwater
L3-8 Definitions
of or found in fresh water; not of the sea.
saltwater
L3-8 Definitions
of or found in salt water; living in the sea.
tide range
L3-8 Definitions
(vertical difference between increase and decrease of tide)
-When the sun and moon are aligned, the tide generating forces of the sun and moon are combined
river
L3-8 Definitions
a large natural stream of water flowing in a channel to the sea, a lake, or another such stream.
waves
L3-8 Definitions
a disturbance on the surface of a liquid body, as the sea or a lake, in the form of a moving ridge or swell
salt wedge estuary
L3-8 Definitions
occur where a large river enters a fairly deep bay with weak tide currents.
well-mixed estuary
L3-8 Definitions
Well mixed- occur where smaller rivers enter shallow estuaries with a relatively large tide range, being rapidly mixed with salrwater, producing a gradual increase in salinity with distance from the river
partially-mixed estuary
L3-8 Definitions
So you have a large river entering into a shallow estuary with a large tide range, or a small river entering a deep estuary with a small tide range. This intermediate condition is much more common than either extreme.
coastal wetlands
L3-8 Definitions
these are coastal land areas covered with water all or part of the year- include river mouths, inlets, bays, sounds, coastal marshes, and mangrove forests. They are some of the earth’s most productive ecosystems and nurseries for species
flushing time
L3-8 Definitions
A measure of the turnover time for fresh water in an estuary.
Know the three kinds of estuaries covered in lecture and in the text. Be able to predict the kind of estuary given a physical description of an estuary. Several factors control the nature of an estuary — What role do each of these play?
Salt Wedge - occur where a large river enters a fairly deep bay with weak tide currents.
Well mixed- occur where smaller rivers enter shallow estuaries with a relatively large tide range, being rapidly mixed with salrwater, producing a gradual increase in salinity with distance from the river
Partially - So you have a large river entering into a shallow estuary with a large tide range, or a small river entering a deep estuary with a small tide range. This intermediate condition is much more common than either extreme.
How are estuaries important to wildlife? What are the characteristics of an estuary that make them such productive ecosystems?
- The rivers bring into the estuary nutrients as well as freshwater. This constant influx of new nutrients allows lots of plant growth
- Where there are plants for food, there will also be animals to eat those plants. The protected, nutrient-rich waters of estuaries are important habitat and nurseries for a wide variety of marine life.
How are estuaries important to people? Why is nearly every major port in North America on an estuary?
- abundant wildlife and available freshwater.
- building large cities require a great deal of land. And much of the available land is along the shores of the estuary
What factors control the flushing time of an estuary? Why is the flushing time important?
- Size of estuary
- Amount of river flow
- Tide range
drainage basin
L3-9 Definitions
the area from which a single stream or river drains all of the water
point-source pollutant
L3-9 Definitions
Pollution from a specific location which is relatively easy to regulate
toxic metals
L3-9 Definitions
lead & mercury,
sediment
L3-9 Definitions
matter that settles to the bottom of a liquid
nutrients
L3-9 Definitions
are ions needed by plants; in other words, fertilizer. Nutrients are a critical part of marine ecosystems because without them, plants can’t grow.
sewage
L3-9 Definitions
refuse liquids or waste matter usually carried off by sewers.
septic system
L3-9 Definitions
A relatively small and simple sewage treatment system, made up of a septic tank and a leach field, often used for homes in rural areas
What is the difference between a point-source pollutant and a non-point source pollutant? Which is easier to control? Why?
Point source- Pollution from a specific location which is relatively easy to regulate
Non-point source- Having a little bit coming from every place such as cars, mowers, or farms. Hardest to regulate
Chesapeake bar is difficult to control because even with stopping the point sources, there are many, many drainage basins from places all around in multiple states that drain various non point toxic substances
How do excess nutrients threaten Chesapeake Bay? What are the sources of excess nutrients? Why are these hard to control? Why is the single largest problem today?
- Too much leads to Algal bloom, which uses up all of the oxygen in the water and creates a dead zone. This kills off all oysters and cause wildlife to leave
- Sources include fertilizers, untreated or under treated sewage
- Excessive nutrients is the greatest problem today
How do coastal wetlands help control pollutants entering into estuaries?
They filter the water
hydrocarbons
L3-10 Definitions
organic molecules consisting of only carbon and hydrogen
crude oil
L3-10 Definitions
Liquid petroleum removed from the ground
oil tanker
L3-10 Definitions
a ship designed to carry oil in bulk.
well blowout
L3-10 Definitions
uncontrolled release of oil and natural gas at well after pressure control has failed at the production site
oil slick
L3-10 Definitions
a film or layer of oil floating on an expanse of water, especially one that has leaked or been discharged from a ship.
bilge tank
L3-10 Definitions
A part of a cargo ship that stores liquid waste as a means for not polluting the ocean environment
skimmer
L3-10 Definitions
collects the oil off the surface of the water.
skimmer
L3-10 Definitions
Vessel picks up oil and water, essentially vacuuming the water
All best in calm water
dispersants
L3-10 Definitions
a liquid or gas used to disperse small particles in a medium.
What are the main uses for crude oil?
L3-10 Concepts
- Gasoline/Diesal fuels
- Lubricants
- Plastics made from unused oil
What is the difference between a point-source pollutant and a non-point source pollutant? Give examples from oil pollution. Note that for oil spills, unlike other point-source pollutants, it is not fully possible to regulate and prevent them. Accidents will still happen.
L3-10 Concepts
Non point source- include cars, changing the oil, or tankers constantly moving oil
Point source- Drilling rigs
What methods are currently used for cleaning up oil spills? For each one listed above, where is it most effective?
L3-10 Concepts
- Taking a tanker plane to disperse the oil and break it up
- Oil Booms- a floating barricade used to collect oil and then lighting on fire
- Skimmer- Vessel picks up oil and water, essentially vacuuming the water
All best in calm water - Collecting by hand- most effective on land
The largest source of oil in the oceans comes from oil washed off roads, and brought to the ocean by rivers and streams. Why is this more difficult to clean up? Why is this more dangerous than large spills?
L3-10 Concepts
This is more difficult to clean up because it is non point source and hard to control. This is more dangerous than larger spills because it causes more oil to be put in the ocean and is next to impossible to regulate. Large spills only account for 3% of oil in the ocean
tidal day
L3-4 Definitions
24 hours and 50 minutes
destructive interference
L3-4 Definitions
When the force of the moon and force of the sun work against each other which makes a lower tide range. high tides are lower and low tides are lower
constructive interference
L3-4 Definitions
When the force of the moon and the force of the sun are working together, cause higher high tides and lower low tides.
coast
L3-5 Definitions
the part of the land near the sea; the edge of the land.
coastal zone
L3-5 Definitions
Warm, nutrient-rich, shallow part of the ocean that extends from the high-tide mark on land to the edge of the continental shelf.
passive margin
L3-5 Definitions
a continental margin that is not a plate boundary
active margin
L3-5 Definitions
A continental margin that is colliding with another plate and as a result is geologically active
submergent coast
L3-5 Definitions
a coastline that is flooding and receding
Caused either by the water level actually rising (transgression)
or by the land getting lower (Subsidence)
beach
L3-5 Definitions
an expanse of sand or pebbles along a shore.
sea cliff
L3-5 Definitions
a steep coastal slope created by the erosive power of waves at its base
wave-cut notch
L3-5 Definitions
a hollow eroded by the impact of waves at the foot of a cliff
wave-cut terrace
L3-5 Definitions
flat section of rock formed by the erosion of a sea cliff
uplifted terrace
L3-5 Definitions
a wave-cut platform that is now exposed at the surface of the Earth by a fall in sea level
emergent coast
L3-5 Definitions
a coastline that is being elevated above sealevel and building out into the water (progradational)
Sea level fall is caused either by the water level actually falling (regression)
or by rising of the land ( uplift)
drowned river valley
L3-5 Definitions
- Water penetrating inland due to rises in sealevel.
fjord
L3-5 Definitions
A long narrow inlet from the sea between steep cliffs or hills
barrier island
L3-5 Definitions
a long ridge of sand or narrow island that lies parallel to the shore
What is an emergent coast and what features would you expect to find on it?
L3-5 Concepts
- Coast that rises out of the sea
- Plate tectonics lift the land
Ex: Sea cliffs, headlands, pocket beaches, wave cut terrace, uplifted terrace
What is an submergent coast and what features would you expect to find on it?
L3-5 Concepts
-Coast sinking into the sea
-land goes down or sea level rises
Can make barrier islands this way
How do emergent coasts form? Which U.S. coasts are emergent?
L3-5 Concepts
-Plate tectonics lift the land
in N American an ex. is New England
Another example is West Coast in America
How do submergent coasts form? Which U.S. coasts are just submergent? What feature of submergent coasts is often found on emergent coasts?
Sea level rises or land goes down
Gulf coast, S Atlantic coast, all coasts in N American area
Where is the sand deposited for a simple breakwater? How about a breakwater that is attached to the shore?
L3-7 Concepts
Sand is deposited parallel to the breakwater, creating a sort of lump along the beach
What happens to longshore transport when a jetty or groin is built? Be able to predict where sand will be deposited versus eroded.
L3-7 Concepts
Longshore transport is disrupted, causing big beaches where its stopped and eroding beaches down the line
