Deck 18: Benthos From the Continental Shelf to the Deep Sea

Question 1

Suspension feeders do badly in mud because of

A) High turbidity near the sediment-water interface
B) Anoxic pore water in the sediment
C) Predation
D) A very low food supply

Answer 1

A

Question 2

Muddy sediments dominated by deposit feeders

A) Tend to be anoxic right at the surface
B) Have low water content
C) Have very high water content far below the sediment-water interface
D) Have very high water content near the sediment-water interface

Answer 2

D

Question 3

Trophic group amensalism

A) Is a negative effect caused by predators eating prey
B) Is a negative effect caused by suspension feeders depleting the water column of food for deposit feeders
C) Is a negative effect caused by deposit feeders making the environment unsuitable for suspension feeders
D) None of the above

Answer 3

C

Question 4

Patchiness on the seabed is caused by

A) Disturbance caused by grazing benthic fishes
B) Burrowing structures generated by large burrowing animals
C) Patchy settlement of larvae of benthic invertebrates
D) All of the above

Question 5

In polar regions a unique supply of organic matter important to the economy of the benthos is

A) Fecal material from birds and mammals
B) Phytodetritus from extraordinarily large-celled diatoms in the water column
C) Sedimentary detritus derived from ice algae
D) Sea grass detritus

Question 6

Particulate organic matter

A) Is deposited on the deep-sea floor in a very irregular way, causing patchiness in food supply
B) Reaches the deep-sea floor but is always too refractory to be of importance to the benthos
C) Never reaches the deep-sea floor
D) Arrives on the deep-sea floor continuously through the year as a drizzle of food supply for the deep-sea benthos

Question 7

Following a disturbance, the later stages of succession in a subtidal soft bottom involve

A) Deeper-burrowing species
B) Shallower-burrowing species
C) Epifaunal species
D) Species adapted to anoxia

Question 8

Until the 1950s deep-sea sampling was hampered by

A) The lack of a sampling device that could dig into the mud
B) The lack of a closing device, resulting in washout of bottom organisms
C) The lack of ships capable of deploying deep-sea samplers
D) All of the above

Question 9

In deep-sea sediments below gyres centers,

A) Organic matter supply is not particularly less than in the deep sea nearer to the continental slope
B) Organic matter is completely absent
C) Sediments are black because of the input of organic matter
D) Sediments have the lowest organic matter in the deep sea

Question 10

Bacteria living in the deep sea

A) Are slow growing in all habitats
B) Are slow growing in abyssal soft sediments but grow rapidly near vents and seeps
C) Are not important in the food of macroinvertebrates anywhere in the deep sea
D) Are very similar to bacteria living in shallow water

Question 11

Temperature in the deep-sea abyssal plain

A) Is the coldest on earth
B) Is seasonally and spatially very stable
C) Has about the same annual range as coastal midlatitude shelf waters
D) Is stable at about 15 degrees C

Question 12

Seamounts

A) Are never found near continental margins
B) Are important sites for open water fisheries
C) Have been protected by international treaties because of their high diversity
D) Are extremely remote coral reefs that reach the surface

Question 13

The number of benthic species

A) Increases continuously from the continental shelf coral reefs to the abyssal plain
B) Increases continuously from the continental shelf soft sediments to those of the abyssal plain
C) Decreases from continental shelf muddy sediments to the continental slope, then increases again
D) Increases from shelf muds to the depths of the continental rise, then decreases toward the abyssal plain

Question 14

Deep water coral mounds

A) Consist of one dominant coral species with very few associated animal species
B) Are very diverse and support a large diverse biota of invertebrates
C) Are known to exist intact for millions of years at a time in any one place
D) Are never found at depths shallower than 200 m

Question 15

Deep-water corals

A) Are made of calcite and therefore not subject to dangers of increased carbon dioxide
B) Have an organic skeleton
C) Are generally made of aragonite and are therefore endangered from increasing dissolved carbon dioxide
D) Are known to have experienced before industrialization carbon dioxide concentrations that are greater than the present day

Question 16

Cold seeps

A) Are found in the same areas as hot vents
B) Have a very different fauna than hot vents
C) Have important types of species in common with hot vents
D) Are always rich in sulfide

Question 17

The high biomass adjacent to hot vents depends upon the release of

A) Sulfur from the vents
B) Nitrogen from the vents
C) Phosphorus from the vents
D) Bacteria from the vents

Question 18

Vestimentiferans can live without a gut because

A) They live near sources of dissolved organic matter
B) They are parasites living within the guts of bivalves
C) They have symbiotic bacteria, which are the source of their nutrition
D) They are protistans

Question 19

Bivalves and vestimentiferans living near vents

A) Have very rapid growth rates
B) Have growth rates similar to typical abyssal benthos
C) Grow only in response to falls of phytoplankton detritus
D) Have very slow growth rates

Question 20

Which of the following statements about hot-vent systems is correct?

A) The same species in hot vents have been found throughout the world ocean
B) Even along a ridge, there is very strong genetic differentiation within a species
C) Species are genetically similar even along a great length of the same ridge system
D) Extinctions of deep-sea vent species are observed constantly

Question 21

Hot vents, while having a very distinctive trophic environment,

A) Consist of localized patches of very low diversity, usually less than 20 species
B) Have not been assayed for biodiversity
C) Comprise the most diverse of all marine environments, including coral reefs
D) Consist of several hundred specialized species