In an estuary, _____ is low while _____ usually is high.
|A)||Biodiversity, primary production|
|B)||Primary production, biodiversity|
|D)||Freshwater flow, transparency|
An estuarine salt wedge is formed by a layer of seawater flowing on top of the outflowing freshwater.
Coastal plain estuaries are far more common on passive margins of continents than on active margins.
As a general rule, fjords are found
|A)||Along the Gulf of Mexico.|
|B)||Where river valleys were drowned.|
|C)||In cold places that have been glaciated.|
|D)||In areas with earthquakes.|
Estuaries are vital to many species as:
|D)||Safe, sterile open areas free of any predators.|
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 which produces little vertical mixing.|
|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.|
The Bay of Fundy in eastern Canada is an estuary with extremely strong tidal currents. Due to these strong tidal currents which of these is most likely to occur?
|A)||It is a negative estuary due to almost no circulation.|
|B)||There is no sedimentation.|
|C)||There is no breeding of marine species due to tidal action.|
|D)||The saltwater wedge goes much further up the estuary.|
Estuary bottoms are usually sandy due to medium-sized sediment particles deposited by both the tide and river.
A deep-water estuary like a fjord is more likely to have:
|A)||No detritus production at all.|
|B)||Less temperature variation|
|C)||Higher bacteria levels with more hydrogen-sulfide production.|
|D)||Fewer migrating species|
Which of these areas will have the highest percentage of burrowing animals?
|A)||A rocky intertidal area.|
|C)||A mangrove forest|
|D)||The uppermost tidal area of a salt marsh.|
All detritus produced in estuarine communities stays within that estuary and does not enter the open ocean or other adjacent communities.
The greatest primary producers of mud flats are:
|D)||Large brown algae.|
Many of these esturine animals survive by burrowing in the sediment. They tend to be:
The majority of the infauna of a mud flat feed on
|D)||Particles suspended in the water.|
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.|
Many of the fishes of estuaries are juvenile forms that return to the sea in adulthood.
Which of these fish is a year-round inhabitant of an estuary?
Shorebirds may specialize on mudflat prey at specific depths due to each bird species' particular adaptation of its:
|C)||Ability to osmoregulate|
Fiddler crabs have been used to study all of these topics but which one?
|B)||Effects of predation on mussels|
Brackish water is:
|B)||Always has a very high bacteria count|
|C)||Contains high levels of hydrogen-sulfide|
|D)||Has an intermediate salinity|
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:
Fleshy esturine plants dilute the salts they take up by accumulating large amounts of water in their tissues.
Mangrove forests and salt marshes can mitigate the destructive forces of natural disasters by:
|A)||Modifying seismic activity in tsunami-prone areas|
|B)||Changing local weather patterns to alleviate hurricanes and typhoons|
|C)||Altering tidal patterns to avoid spring tides|
|D)||Acting as buffers or barriers to violent ocean surges of water resulting from natural disasters.|
Salt-marsh plants typically grow on the fringes of estuaries where their tops are exposed to air even at high tide.
As sediment builds up around bases of cordgrass it creates a firmer shore type. Thus this plant may give way to:
All of the following can be found on or near mangroves except for which one?
Mangrove forests can be considered to be the tropical equivalent of salt marshes in terms of productivity.
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 have already caught all of them.|