Marine Biology (Castro), 8th Edition

Chapter 12: Estuaries: Where Rivers Meet the Sea

Chapter Quiz

1
In an estuary, _____ is low while _____ usually is high.
A)Biodiversity, primary production
B)Primary production, biodiversity
C)Biomass, competition
D)Freshwater flow, transparency
2
An estuarine salt wedge is formed by a layer of seawater flowing on top of the outflowing freshwater.
A)True
B)False
3
Coastal plain estuaries are far more common on passive margins of continents than on active margins.
A)True
B)False
4
As a general rule, fjords are found
A)Along the Gulf of Mexico.
B)Where river valleys were drowned.
C)In cold places.
D)In areas with earthquakes.
5
In Northern Hemisphere estuaries, marine organisms can penetrate farther upstream on the left side (when facing land) due to the Coriolis effect on water flow.
A)True
B)False
6
Along the Caribbean coast of Mexico, some coastal lagoons have stratified water-fresh above, salty below--with no mixing. Why might this be so?
A)Very low tidal range
B)The fresh water is colder than the seawater
C)The fresh water does not flow downstream
D)The seawater has the same density as fresh water
7
The Bay of Fundy in eastern Canada is an estuary with extremely strong tidal currents. Why might this be so?
A)It is a negative estuary.
B)It is short and wide.
C)There is no Coriolis effect that far north.
D)It is long and narrow.
8
Estuary bottoms are usually sandy due to medium-sized sediment particles deposited by both the tide and river.
A)True
B)False
9
A deep-water channel dredged in a shallow estuary may contain stagnant water. This is because
A)The deeper water is more salty.
B)The deeper water is more dense.
C)Bacteria do not carry on composition in deeper water.
D)The shallow areas act as a sill that restricts circulation.
10
In the sediments of mudflats, oxygenated areas can be found
A)Only above the sediments, in the water column.
B)Along burrows of shrimp.
C)Where organic matter accumulates.
D)Where bacteria are common.
11
Detritus produced in estuarine communities stays within that estuary and does not enter the open ocean or other adjacent communities.
A)True
B)False
12
Primary producers of mud flats include
A)Seagrasses.
B)Salt grass.
C)Benthic diatoms.
D)Brown algae.
13
Survival of osmoconforming animals is benefited by burrowing in the sediment.
A)True
B)False
14
The majority of the infauna of a mud flat feed on
A)Diatoms.
B)Green algae.
C)Detritus.
D)Particles suspended in the water.
15
To survive in an estuary, a filter-feeding crab must have a means to
A)Catch the small amount of organic matter in the area.
B)Clean mud off its filtering mechanism and gills.
C)Shade its eyes from bright light.
D)Deal with hypersaline water.
16
Many of the fishes of estuaries are juvenile forms that return to the sea in adulthood.
A)True
B)False
17
A year-round inhabitant of an estuary is which fish?
A)Salmon
B)Anchovy
C)Killifish
D)Leopard shark
18
Shorebirds may specialize on mudflat prey at specific depths due to each bird species' particular shape and length of beak.
A)True
B)False
19
Fiddler crabs are used to study all of these topics but which one?
A)Biological clocks
B)Effects of predation on mussels
C)Color changes
D)Behavior
20
Clams of mud flats often have
A)The ability to dig quickly into sand.
B)Short, fringed siphons.
C)Shells cemented to the sea floor.
D)Long siphons.
21
Cat-tails (Typha) are plants of freshwater marshes, but they can be found at the extreme upper (landward) end of an estuary. Cat-tails are
A)Euryhaline.
B)Stenohaline.
C)Eurythermal.
D)Osmoregulators.
22
Fleshy plants dilute the salts they take up by accumulating large amounts of water.
A)True
B)False
23
Kelps and other large algae dominate salt-marsh communities on the edges of estuaries.
A)True
B)False
24
Salt-marsh plants typically grow on the fringes of estuaries where their tops are exposed to air even at high tide.
A)True
B)False
25
As sediment builds up around bases of cordgrass, this plant may give way to
A)Pickleweed.
B)Enteromorpha.
C)Mangroves.
D)Eelgrass.
26
All of the following can be found on or near mangroves except for which one?
A)Sponges
B)Crabs
C)Ribbed mussel
D)Mudskipper
27
Mangrove forests can be considered to be the tropical equivalent of salt marshes.
A)True
B)False
28
A luxurious new condominium is built on land created by dumping soil and other fill on top of a salt marsh. The fishing near the condominium rapidly becomes poor. Which of these reasons probably is NOT why there are fewer fish?
A)A nursery area has been destroyed.
B)Food sources for small fish and their prey have been destroyed.
C)Local water circulation has changed.
D)The people who inhabit the condominium caught all of them.
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