Ch 16, Oceans, Coastal Systems, and Wind Processes

Question 1

Salinity

Answer 1

Concentration of dissolved solids in a solution

Question 2

what is the average salinity range?

Answer 2

3.5% or 35%, ranges from 30-40

Question 3

What is seawater called when salinity is above or below 3.5%

Answer 3

above = brine

below: brakish

Question 4

What are the 3 horizontal layers in the sea

Answer 4

1- Mixing zone

2- thermocline transition zone

3- deep cold zone (80% salinity)

Question 5

True or false: Sea water freezing point deep at the bottom is lower than that of plain water

Answer 5

True, because of the salt

Question 6

Explain ocean acidification

Answer 6

As the oceans absorb excess carbon dioxide from the atmosphere, the process of carbonation forms carbonic acid in seawater, resulting in a lowering of the ocean pH

Question 7

Littoral zone:

Answer 7

Landward, it extends to the highest waterline reached on shore during a storm. Seaward, it extends to where water is too deep for storm waves to move sediments on the seafloor—usually around 60 m in depth

Question 8

How often can sea levels change and why?

Answer 8

They can change daily due to tides and over the long term due to factors like climate change, tectonic movements, and glaciation

Question 9

Tides and their causes

Answer 9

Tides are regular changes in sea level that happen twice a day, with rises and falls ranging from barely noticeable to several meters

Cause: By the gravitational pull of both the Sun and the Moon

Question 10

The 4 tides:

Answer 10

Flood tide: riding tide during the daily tidal cycle

ebb tide: falling tide during the daily tidal cycle

Spring tide: greatest tidal range between high and low tides (full moon and new moon)

neap tide: low tidal range (quarter moon)

Question 11

Waves:

Answer 11

Friction between moving air (wind) and the water on ocean surface generates waves

Question 12

Wave refraction

Answer 12

When waves approach an irregular coastline, resulting in different erosion potential along the coast

Question 13

longshore current (zigzag)

Answer 13

depend on wind
direction and the
resultant wave
direction, transports large amounts of sand and sediment (beach drift)

Question 14

Coastal erosion

Answer 14

More sediment is removed
than deposited

Rugged, high relief, and
tectonically active

Such as coastlines of the
Pacific Ocean along North
and South America

Question 15

Depositional landforms

Bay barrier, lagoon, beach, and tombolo

Answer 15

More sediment is deposited than removed.

Depositional coasts are
along land of gentle relief,
such as the Atlantic and
Gulf coastal plains.

Relatively passive, and
tectonically inactive
Beach

Question 16

beach protection goals and structures

Answer 16

Stop sand accumulation or force more desirable
accumulation patterns

structures (3):

Groins – slow drift
action along coast.

Jetties – block
material from harbor
entrances.

Breakwaters – create
zones of still water

Question 17

Barrier beaches:

Answer 17

long, narrow depositional features, generally of sand, that form offshore roughly parallel to the coast

Sediment from alluvial costal plains

Question 18

Barrier islands:
(barrier beaches on crack)

Answer 18

When the features of barrier beaches are broader and more extensive

Sediment from alluvial costal plains

Some parts of barrier
island landforms are
fragile and easily
disturbed.

Human-built
structures on these
landforms are
vulnerable to erosion
and sea level change.

Development
continues despite the
risks.

Question 19

Corals and their formation

Answer 19

Corals secrete CaCO3 in their bottom half, forming hard, calcified external skeleton

Thrive mostly in warm tropical oceans

Live corals build on the
foundation of older
skeletons

Question 20

Coral reef:

Answer 20

The accumulation of CaCO3 coral
skeletons lithified into rock

Question 21

Coral bleaching:

Answer 21

When the coral turns white by expelling their own nutrient-supplying algae

Possible causes include local pollution, disease, sedimentation, changes in ocean salinity, and increasing oceanic acidity

Question 22

Coastal wetlands:

Answer 22

Have great biological productivity—lush plant growth and spawning grounds for fish, shellfish, and other organisms

Mangrove swamp: The name for the trees, shrubs, palms, and ferns that grow in these intertidal areas, as well as for the habitat

Salt marshes: Consist mainly of halophytic (salt-tolerant) plants (mainly grasses) and usually form in estuaries and in the tidal mud flats behind barrier beaches and spits

Question 23

Eolian:

Answer 23

The work of wind, similar to river stream. Causes erosion, shifting or transporting materials such as dust, sand, snow, and deposition

Question 24

Stronger wind is required for which kind of particles?

Answer 24

For large and smaller particles, since large particles are typically heavy and small particles are cohesive

Intermediate particles are the easiest to transport

Question 25

Eolian (saltation) process:

Answer 25

bouncing and skipping action to transport particles larger than about 0.2 mm

Question 26

Eolian surface creep process:

Answer 26

When particles are too big for saltation so they just slide and roll along the ground surface

Question 27

Eolian deflation process:

Answer 27

lifting and removal of
individual particles by wind

Question 28

Eolian abrasion process:

Answer 28

grinding and shaping
of rock surfaces by the
‘sandblasting’ action of particles captured in the air.

Question 29

What causes desert pavement?

Answer 29

Deflation, it can lead to the formation of desert
pavements, which predominate across most
subtropical landscapes

Only 10% of desert areas are covered with
sand.

Question 30

What forms sand dunes

Answer 30

Larger deposits of sand grains

Question 31

Erg or sand sea:

Answer 31

Extensive area of sand dunes

Question 32

Coastal dune:

Answer 32

formed by sediment supplied by the work of ocean waves (and waves on large lakes) and by fluvial processes that move sediment onto deltas

Question 33

Loess deposits:

Answer 33

Accumulation of fine-grained particles that have been blown large distances

Unstratified, evenly mixed, and can be very deep (e.g.,
> 300-m in the Loess Plateau of China)

Unstratified, evenly mixed, and can be very deep (e.g.,
> 300-m in the Loess Plateau of China).