Chapter 17—The Open Sea
MULTIPLE CHOICE
1. In tropical water, the photic zone in the open ocean can extend down to:
a.
10 m.
b.
20 m.
c.
100 m.
d.
200 m.
e.
1000 m.
2. The epipelagic refers to the location of pelagic animals that can extend down to:
a.
10 m.
b.
20 m.
c.
100 m.
d.
200 m.
e.
1000 m.
3. Pelagic organisms live:
a.
in the water column.
b.
on the sediment.
c.
in the sediment.
d.
in hydrothermal vents.
e.
close to shore.
4. Those organisms that can swim strongly against ocean currents are called:
a.
plankton.
b.
neuston.
c.
nekton.
d.
macroplankton.
e.
epifauna.
5. Those organisms that cannot swim against the ocean currents are collectively called:
a.
plankton.
b.
nekton.
c.
seston.
d.
demersal.
e.
infauna.
6. All the following are used to classify plankton except:
a.
taxonomic groups.
b.
functional groups.
c.
life history.
d.
light spectrum requirements.
e.
size.
7. Phytoplankton of the open ocean are very small in order to:
a.
avoid detection by grazers.
b.
maximize their surface area.
c.
increase their sinking rates.
d.
none of the above
8. The most abundant plankton are the:
a.
phytoplankton.
b.
bacterioplankton.
c.
viriplankton.
d.
zooplankton.
e.
macroplankton.
9. Archaeans and bacteria are generally included in the:
a.
seston.
b.
tripton.
c.
bacterioplankton.
d.
viriplankton.
e.
pleuston.
10. The base of the food web in the open ocean and the bottom beneath the open ocean is:
a.
algae.
b.
seagrasses.
c.
chemosynthetic bacteria.
d.
phytoplankton.
e.
detritus.
11. Primary productivity is limited in surface waters of the open ocean by:
a.
sunlight.
b.
nutrients.
c.
carbon dioxide.
d.
oxygen.
e.
temperature.
12. The dominant primary producers in tropical open ocean areas are:
a.
large net phytoplankton.
b.
small nanoplankton.
c.
diatoms.
d.
algae.
e.
seaweeds.
13. Kinetic organisms can move themselves by all except:
a.
flagella.
b.
jet propulsion.
c.
undulation of the body.
d.
using turbulent mixing.
14. Particles suspended in the sea are called:
a.
seston.
b.
tripton.
c.
bacterioplankton.
d.
viriplankton.
e.
nekton.
15. Marine snow is composed of:
a.
inorganic nutrients.
b.
flocculated marine salts.
c.
particulate organic matter.
d.
frozen seawater.
e.
terrestrial materials.
16. Marine snow refers to:
a.
neston.
b.
seston.
c.
cobwebby aggregates of mucus.
d.
fecal pellets.
e.
necktonic organisms.
17. Phytoplankton patchiness in the epipelagic can occur when:
a.
water clarity declines.
b.
there is an influx of nutrients.
c.
surface waters plunge to depths.
d.
fish aggregate.
e.
hydrothermal vents erupt.
249 Chapter 17—The Open Sea
18. Macroplankton are organisms visible to the naked eye and generally exceed ____ in size.
a.
5 mm
b.
1 mm
c.
5 mm
d.
10 mm
e.
10 cm.
19. Plankton that can be caught with a standard plankton net are called:
a.
nanoplankton.
b.
picoplankton.
c.
microplankton.
d.
megaplankton.
e.
gigaplankton.
20. An example of megaplankton would be:
a.
larval fishes.
b.
Sargassum seaweed.
c.
invertebrate larvae.
d.
green flagellates.
e.
copepods.
21. An example of mesoplankton would be
a.
larval fishes.
b.
Sargassum seaweed.
c.
invertebrate larvae.
d.
green flagellates.
e.
bacteria.
22. Those organisms that remain planktonic for their whole lives are called:
a.
meroplankton.
b.
holoplankton.
c.
nanoplankton.
d.
seston.
e.
nekton.
23. Those organisms that live only part of their life history as plankton are called:
a.
meroplankton.
b.
holoplankton.
c.
nanoplakton.
d.
seston.
e.
pleuston.
24. Nutrient-rich microenvironments can occur in the open ocean around:
a.
viriplankton.
b.
discarded larvacean houses.
c.
marine snow.
d.
b and c
25. The deep scattering layer refers to:
a.
an area where organisms are spread apart in a random manner.
b.
a dense aggregation of migratory zooplankton and fish.
c.
a safe area where zooplankton can quickly scatter to avoid predators.
d.
where sonar from whales travels rapidly to facilitate their communication.
e.
the abyssal zone.
26. The primary organisms that make up the deep scattering layer are:
a.
zooplankton and fishes.
b.
phytoplankton.
c.
seston.
d.
nanoplankton.
e.
marine snow animals.
27. Each day the animals of the deep scattering layer
a.
must form mucus nets to protect themselves from predators.
b.
make a nocturnal migration to the DSL to feed.
c.
make a nocturnal migration to the epipelagic to feed.
d.
make a daytime migration to the epipelagic to feed.
e.
migrate to a depth of 1.6 km to feed.
28. The primary reason for the daylight migration of many pelagic animals to deeper waters is:
a.
escape from visual predators.
b.
escape from the harmful effects of the sun.
c.
preference for the colder waters of the deep.
d.
the abundance of food in deeper waters.
29. All of the following are adaptations against predation in the open ocean except:
a.
transparent bodies.
b.
colorful bodies.
c.
colonial lifestyles.
d.
countershading.
e.
silvery coloration.
30. Common megaplankton of the open ocean include all but
a.
cnidarians.
b.
mollusks.
c.
gelatinous zooplankton.
d.
diatoms.
e.
salps.
31. Megaplanktonic molluscs without a shell are called:
a.
cephalopods.
b.
thecosome pteropods.
c.
gymnosome pteropods.
d.
nudibranchs.
e.
oceanic limpets.
32. Thecosome pteropods are primarily
a.
herbivores.
b.
carnivores.
c.
detritovores.
d.
omnivores.
e.
scavengers.
33. Gymnosome pteropods are primarily
a.
herbivores.
b.
carnivores.
c.
detritovores.
d.
omnivores.
e.
filter feeders.
34. All of the following are adaptations against sinking in the open ocean except:
a.
long spines and projections.
b.
lipid droplets.
c.
dense tissues.
d.
gas bladders.
e.
small size.
35. To avoid sinking the purple sea snail
a.
uses jet propulsion from the mantle to move upward.
b.
has wings on its foot for swimming.
c.
has gas vacuoles in its shell.
d.
produces a bubble raft surrounded by mucus.
e.
fills its liver with low-density oil.
36. Pelagic snails that produce a bubble raft in order to remain afloat are
a.
pteropods.
b.
purple sea snails.
c.
cowries.
d.
littorine snails.
e.
abalone.
37. Salps play an important ecological role as consumers of:
a.
bacteria.
b.
diatoms.
c.
krill.
d.
fish larvae.
e.
jellyfish.
38. Common nekton include
a.
tuna.
b.
billfish.
c.
jelly fish.
d.
both a and b
e.
both b and c
39. All of the following are adaptations of tuna for fast swimming except:
a.
warmer than ambient body temperature.
b.
retractable pectoral fins.
c.
rounded tail.
d.
operculum that lies tightly against the body.
e.
sickle-shaped tail.
40. Water comprises at least ____ of the body of salps.
a.
5%
b.
10%
c.
25%
d.
70%
e.
95%
41. Which fish can grow to weigh a ton, and is known for high levels of internal and external parasites?
a.
billfish.
b.
skipjack tuna.
c.
ocean sunfish.
d.
great white shark.
e.
pilot fish.
42. Which non-mammal organism has a connection to supply nutrients to developing embryos similar to
the mammals?
a.
sea snake
b.
sea turtles
c.
hammerhead shark
d.
manta ray
e.
sea turtle
43. The manta ray feeds on:
a.
larger fish.
b.
surface and diving birds.
c.
squid.
d.
small fish and plankton.
e.
other rays.
44. Which organism is considered part of the nekton?
a.
frigate bird
b.
penguin
c.
cormorant
d.
snowy plover
e.
albatross
TRUE/FALSE
45. Coastal upwelling is a common source of nutrients in the open ocean.
46. Pyrosomes are gelatinous zooplankton composed of a colony of individual pelagic tunicates.
47. Salps and amphipods of the genus Phronima have a commensal symbiosis.
48. Because zooplankton do not need sunlight they tend to be most concentrated in deeper waters away
from the surface.
49. Physically, the open ocean is a very stable environment.
50. The body temperature of tunas is 8-10° C higher than ambient water temperature.
254 Chapter 17—The Open Sea
51. Many zooplankton migrate daily from the DSL to the epipelagic zone.
52. Marine snow is an important source of food for many pelagic organisms.
53. Bacteria play an insignificant role in the pelagic realm.
54. Squids are dominant nektonic predators in the open ocean.
MATCHING
Match the organism group with its most closely associated classification group.
a.
Kinetic plankton
b.
Bacterioplankton
c.
Macroplankton
d.
Meroplankton
55. Classified by taxonomic group
56. Classified by motility
57. Classified by size
58. Classified by life history
Match the organism group with its most closely associated classification group.
a.
Microplankton
b.
Holoplankton
c.
Nekton
d.
Viriplankton
59. Life history
60. Spatial distribution
61. Size
62. Taxonomic group
Match the phenomena with a closely associated term.
a.
aggregations of nekton
b.
migratory zooplankton
c.
marine snow
63. Deep scattering layer
64. Micropatchiness
65. Macropatchines
Match the characteristic with the most closely associated organism.
a.
winged, shell absent
b.
winged, small shell
c.
bubble raft
66. Purple sea snail
67. Thecoscome pteropod
68. Gymnosome pteropod
Match the characteristic with the species.
a.
lack swim bladder
b.
cartilage layer
c.
lack teeth
d.
viviparous
69. Billfish
70. Tuna
71. Ocean Sunfish
72. Hammerhead Shark
Match the size with the most closely associated plankton type.
a.
2.0 mm
b.
0.02 mm
c.
200 mm
d.
20 mm
73. Megaplankton
74. Mesoplankton
75. Microplankton
76. Macroplankton
256 Chapter 17—The Open Sea
Match the size with the most closely associated plankton type.
a.
0.02 m
b.
2.0 m
c.
0.2 m
77. Nanoplankton
78. Picoplankton
79. Femtoplankton
Match the location with its most closely associated group.
a.
entire life in water column
b.
part of life in water column
c.
animals live at or near the surface
80. Neuston
81. Holoplankton
82. Meroplankton
Match the species with its most closely associated trophic level.
a.
krill
b.
diatoms
c.
copepods
d.
squid
83. Primary producer
84. Herbivore
85. 2nd level consumer
86. 3rd level consumer
Match the species with its most closely associated size/ trophic level.
a.
copepods
b.
krill
c.
foraminiferans
87. Microzooplankton
88. Mesozooplankton
89. Macrozooplankton
ESSAY
90. What is the deep scattering layer? How was it discovered? What organisms commonly compose this
layer?
91. What is meant by the terms “holoplankton” and “meroplankton”?
92. What is micropatchiness, and what factors give rise to micropatchiness in the open sea?
93. What is the ecological importance of salps and larvaceans to the pelagic food web?
94. Describe at least 3 of the adaptations used by plankton in their efforts to remain near the surface.
95. Describe the open-ocean planktonic food chain, and elaborate on why its supports few large animals.
96. Define the term “marine snow.” What is it composed of? How is it affected by bacteria and other
marine zooplankton? How does marine snow aid in the deposition of marine sediments?
259 Chapter 17—The Open Sea
97. Trace the open ocean microbial loop, starting with DOM released by unicells, and follow how it is
reprocessed through the bodies of various microorganisms, finally leading up in the bodies of
zooplankton.