Deck 16: The Tidelands: Rocky Shores, Soft-Substratum Shores, Marshes, Mangroves, Estuaries, and Oyster Reefs

Question 1

Intertidal organisms

A) Are usually the same temperature as air temperature at the time of low tide
B) Always suffer from high heat stress
C) Can never move to a place where they can avoid drying out
D) May be cooler than a comparably sized nonliving object on a hot day at the time of low tide

Answer 1

D

Question 2

If there is genetically based color polymorphism in an intertidal bivalve, solar heat stress would create conditions for light-colored forms to be found

A) Only at low latitudes
B) In the lower part of the intertidal only
C) In greater frequency in low latitudes
D) In greater frequency in high latitudes

Answer 2

C

Question 3

Mobile carnivores are

A) Usually found in the highest part of the intertidal
B) Not usually able to get to prey in the highest part of the intertidal
C) Generally nonselective
D) Always visual in prey detection

Answer 3

B

Question 4

Swash riders

A) Always are found in the lowest part of the intertidal
B) Migrate in longshore currents
C) Change vertical position to stay in wave-stirred sediments
D) Change vertical position to stay in moist, undisturbed sediments

Question 5

Salt marsh zonation and rocky shore zonation have the following in common

A) Zonation is controlled by a combination of ecological interactions and physical factors
B) Zonation is controlled in both cases by herbivory
C) The lower limit of a zone is determined by ecological interactions only
D) The highest part of the intertidal is the most stressful for species dominating zones

Question 6

Connell's experiments demonstrated

A) Barnacles settle randomly in the intertidal
B) The adult vertical distribution is greater than that of the newly settled larvae
C) Predation by snails is concentrated in the low part of a rocky shore
D) All of the above

Question 7

Infaunal bivalve species may reduce competition by

A) Feeding on different types of phytoplankton
B) Living at different depths below the sediment-water interface
C) Living on the sediment surface
D) Being inactive for much of the year and being active in a time such as winter when other bivalves are inactive

Question 8

Keystone species

A) Affect community structure by preying on competitively important prey species
B) Are superior competitors and affect community structure
C) Are primary producers
D) Are found only in the intertidal zone

Question 9

Predation is generally

A) Important in rocky shores but unimportant on soft intertidal sediments
B) Seasonal only on rocky shores
C) A major factor in community structure in areas where migratory shorebirds stop
D) Restricted in importance on rocky shores to starfish only

Question 10

Early dominants in intertidal seaweed succession

A) Inevitably give way to species later in the successional sequence
B) Are poor colonizers
C) Are resistant to grazing
D) Are usually not as well defended chemically as species later in succession

Question 11

In an estuary with a very high flushing rate

A) Marine invertebrate larvae will settle in dense numbers within the estuary
B) Long-lived planktotrophic larvae originating within the estuary will settle in the estuary in higher densities than lecithotrophic larvae originating within the estuary
C) Planktonic larvae that rise on the ebb tide will have high settlement rates within the estuary
D) None of the above

Question 12

In a rocky shore, the competitively superior species will take over

A) Unless there is little larval recruitment of that species
B) Under any circumstances
C) Only if its predator is abundant
D) Unless there is facilitation between individuals of that species

Question 13

Nutrients increase due to upwelling and there are more large carnivorous fish. This is an example of

A) The appearance of a foundation species
B) A bottom-up process
C) The effect of a keystone species
D) Competitive displacement

Question 14

Zonation

A) Is best developed on exposed shores with strong wave energy
B) Is best developed in soft sediment intertidal environments
C) Is best developed in protected rocky shore environments
D) Only develops when there is little vertical tidal range

Question 15

In protected soft sediment shores

A) Food is derived from decaying seaweed on the sediment surface
B) Food is derived from deposits of phytodetritus
C) Deposit-feeding invertebrates are often patchy
D) All of the above

Question 16

Benthic species in estuaries may be adapted to estuarine flow of larvae to the coastal zone

A) By crawling within the sediment toward higher salinity
B) By having planktonic larvae rise with the flooding tide and staying near the bottom on the falling tide
C) By never living on the sediment surface
D) By digging deeper than in open marine sediments

Question 17

The loss of oysters and other estuarine suspension feeders

A) Results in negative impacts on sea grasses
B) Has caused an expansion of sea grass in estuaries
C) Has resulted in a great increase of phytoplankton throughout large estuaries
D) Has resulted in a compensating increase of benthic diversity

Question 18

Estuaries

A) Are ephemeral and therefore of no biological importance
B) Are extremely important as nurseries for many species of fish
C) Have salinities too low to support much marine life
D) Have relatively low primary production, so species must feed outside the estuary

Question 19

In an estuary

A) Marine benthos penetrate not as far upstream as zooplankton
B) Marine benthos live with more salinity variation than zooplankton
C) Marine benthos penetrate just as far upstream as zooplankton
D) Marine benthos penetrate farther upstream than do zooplankton

Question 20

Spartina salt marsh plants spread mainly by

A) Seed set as they are flowering plants
B) Vegetative growth via the rhizomal system
C) Fragmentation and water-borne transport of adult plants
D) Subterranean spores

Question 21

In estuaries, which order of subhabitats goes from higher to lower salinity?

A) Oligohaline to mesohaline
B) Oligohaline to polyhaline
C) Polyhaline to mesohaline
D) Tidal freshwater to oligohaline

Question 22

Lower intertidal salt marsh plants

A) Can grow well in the high intertidal zone
B) Are severely limited in growth in the high intertidal zone
C) Are no more salt-tolerant than high intertidal plants
D) Can grow in very deep water

Question 23

Detritus derived from Spartina

A) Is very digestible and is consumed by many invertebrate species
B) Cannot be broken down by bacteria
C) Is never produced because all Spartina leaves are consumed by herbivores
D) None of the above

Question 24

Spartina salt marshes

A) Have an abundance of oxygen for root uptake
B) Consist of plants that grow separately from each other
C) Have adaptations to take up oxygen from pore waters at low concentrations
D) Have only one species of plant in the marsh usually

Question 25

Salt marsh sediment

A) Is usually very poor in organic matter
B) Is very rich in organic matter
C) Has a very high water content relative to coastal muddy sediments
D) Tends to have large grain size

Question 26

Vertical zonation in Spartina salt marshes

A) Is based on physiological tolerances that are essentially the reverse of rocky shore species
B) Is present and based on differential grazing at different tidal heights
C) Consists of species with physiological tolerance to salt and desiccation that is strikingly similar to sessile species on rocky shores
D) Is usually quite weak

Question 27

Mangroves

A) Have roots that penetrate into the oxygenated sediment below
B) Must have roots adapted to the anoxic sediment
C) Cannot live in regular sea water
D) Are common in high-latitude estuaries

Question 28

In a year when rainfall is plentiful within an estuary we might expect

A) Larval recruitment within the estuary to be at a low rate
B) Salinity to be generally lower throughout the estuary
C) Larger supplies of nutrients
D) All of the above

Question 29

Bromine-containing compounds

A) Are used by planktonic eggs as sperm attractants
B) Are common pollutants in mangroves
C) Are secreted by soft-sediment benthos to repel competitors
D) Are among the very few compounds not used by marine organisms

Question 30

Which of the following is not a foundation species?

A) A dominant mangrove species in a mangrove forest
B) An abundant sea grass species
C) A dominant species of cord grass in a salt marsh meadow
D) A barnacle species that wins out in competition over other species

Question 31

Zonation in salt marshes

A) Depends on increased resistance to environmental stress as you go up the intertidal zone
B) Is explained by grazing by herbivores
C) Depends on increased resistance to environmental stress as you do down in the intertidal zone
D) Is generally unpredictable

Question 32

Mangroves are found

A) Only in the tropical Atlantic
B) In the tropics on quiet shores in all oceans
C) Only on tropical islands in open ocean environments
D) A minimum of three meters in depth

Question 33

Mangroves

A) Can excrete salt through glands
B) Store salt in the leaves
C) Can completely avoid uptake of salt
D) Do not live in saltwater

Question 34

Mangrove roots

A) Are always embedded in sediment
B) Have chemical defenses in the roots against invertebrates
C) Are often in water and colonized by sessile invertebrates
D) Point into the air

Question 35

Oyster reefs may disappear from

A) Lack of shell production
B) Overharvesting
C) Pollution
D) All of the above

Question 36

Oyster reefs

A) Have greatly declined in United States estuaries
B) Are the main source of edible oysters for sale
C) Are essentially as abundant as they were over a hundred years ago
D) Nearly disappeared but have been restored