Deck 12: The Plankton, Productivity, and Food Webs

Question 1

The only zone of the ocean with sufficient light for photosynthesis is the ________.

A) euphotic zone
B) aphotic zone
C) disphotic zone
D) None of these choices is correct.
E) All of these choices are correct.

Answer 1

A

Question 2

The total productivity of upwelling areas is greater than the total productivity of open-ocean areas.

Answer 2

False

Question 3

The plankton, benthos, and nekton are subdivisions of the ________.

A) seafloor
B) littoral
C) oceanic water column
D) organisms
E) continental shelf

Answer 3

D

Question 4

Greater mixing and nutrients from the land cause the coastal areas to generally have higher primary productivity than the open ocean.

Question 5

The total primary production of the world's oceans is determined more by the large seaweeds than it is by the single-celled microscopic phytoplankton.

Question 6

Organisms that float, but cannot swim against the tides and waves, are known as ________.

A) photon
B) aphoton
C) plankton
D) nekton
E) benthos

Question 7

At low latitudes, primary production is controlled more by the seasonality of the sunlight than by the availability of nutrients.

Question 8

The standing stock of a population is equivalent to its biomass.

Question 9

The shorter food chains of coastal and upwelling areas generally are more efficient than longer open-ocean food chains.

Question 10

If both primary productivity and grazing are large, the standing stock cannot be small.

Question 11

Productivity tends to be higher in the open ocean than the coastal ocean.

Question 12

Gross primary production is the rate of production of organic material by photosynthesis required for both the respiration of the plants or algae and the production of new material.

Question 13

Approximately 15 percent of the world's ocean area produces eighty-five percent of the ocean's harvest.

Question 14

In grams of carbon per square meter per day, the open-ocean environment is as productive as a tropical rainforest.

Question 15

If the rate of uptake of dissolved inorganic carbon by phytoplankton is measured, the rate of production of organic matter can be calculated.

Question 16

Net primary production equals gross primary production minus the respiration requirements of plants or phytoplankton.

Question 17

Nutrients tend to be liberated by decomposition of organic matter at depth and returned to the surface by the physical processes of vertical circulation.

Question 18

Primary productivity per square meter of ocean surface is, on the average, higher in the neritic zone than in the oceanic zone.

Question 19

In temperate regions, both winter mixing and summer's increasing solar radiation control primary production.

Question 20

The upper boundary of the aphotic zone is determined by the depth of solar light penetration.

Question 21

Productivity in tropical oceans is limited by nutrient availability.

Question 22

At temperate latitudes, a stable water column with a pycnocline near the surface will ________ primary production in the spring and ________ primary production in late summer.

A) decrease; increase
B) increase; increase
C) increase; decrease
D) decrease; decrease
E) None of these is correct; both will be moderately productive.

Question 23

Chlorophyll a absorbs energy mostly in the blue and red wavelengths.

Question 24

Primary productivity is measured in terms of gC/m²/day.

Question 25

The arctic region has low annual productivity because ________.

A) the nutrient supply is low
B) the water is cold
C) ice covers the water in winter
D) the intensity of solar radiation is low
E) the oxygen level of the surface waters is low

Question 26

Although light, nitrogen, and phosphorous are abundant in the Pacific and Southern Oceans, the plankton are less abundant due to ________.

A) low surface temperature
B) low oxygen levels at the surface
C) lack of iron in surface waters
D) low surface temperature and lack of iron in surface waters
E) low surface temperature, low oxygen levels at the surface, and lack of iron in surface waters

Question 27

A high-oxygen content and a low-nutrient content in surface seawater indicate that a population of ________ are present.

A) animals
B) phytoplankton
C) bacteria
D) decomposers
E) None of these is correct; they indicate no life presence.

Question 28

Upwelling areas are more productive than oceanic areas because ________ in upwellings.

A) organic matter is more concentrated
B) food chains are shorter
C) there are more nutrients
D) All of these are correct.
E) None of these is correct.

Question 29

Satellites can detect ocean color.

Question 30

Approximately the same amount of primary productivity occurs in the oceans as occurs on land.

Question 31

The most numerous and greatest biomass of herbivores are ________.

A) zooplankton
B) fish
C) the great whales
D) primary consumers
E) zooplankton and primary consumers

Question 32

When new marine phytoplankton biomass is produced by photosynthesis, dissolved carbon dioxide is converted to ________.

A) carbon dioxide gas
B) carbon dioxide solids
C) soluble inorganic compounds
D) organic carbon compounds
E) None of these is correct.

Question 33

When primary productivity is high, the standing crop remains high and nearly constant.

Question 34

Phytoplankton biomass can be measured by satellite.

Question 35

Productivity is higher at a surface convergence than surface divergence.

Question 36

A standing crop of phytoplankton can be measure by ________.

A) determining the chlorophyll a content of a sample
B) weighing the cells in a sample
C) counting the cells in a sample
D) All of these are correct.
E) None of these is correct.

Question 37

In terms of grams of carbon per square meter per day, the open-ocean environment is about as productive as ________.

A) prairie land
B) alpine forests
C) deserts
D) intensively farmed fields
E) tropical rain forests

Question 38

Areas of divergence promote higher rates of primary production.

Question 39

Which of the following is not necessary for photosynthesis?

A) light
B) chlorophyll
C) oxygen
D) water
E) carbon dioxide

Question 40

Primary productivity is best described as ________.

A) population
B) standing crop
C) life expectancy
D) rate of birth minus rate of death
E) rate of production of organic carbon

Question 41

The biomass of planktonic, unicellular algae in tropical regions ________.

A) remains nearly constant over the year
B) increases during the summer months
C) decreases during the summer months
D) increases during the winter months
E) decreases during the winter months

Question 42

The highest rates of productivity in temperate waters occur in ________.

A) spring
B) winter
C) summer
D) fall
E) Productivity is the same during all seasons.

Question 43

As a general rule, total biomass ________, size of individuals ________, and number of individuals ________ as you move up a trophic pyramid.

A) increases; decreases; decreases
B) decreases; increases; decreases
C) increases; decreases; increases
D) decreases; decreases; increases
E) increases; increases; increases

Question 44

Adding iron to the surface of the ocean has been shown to ________.

A) have no impact on phytoplankton community composition
B) increase phytoplankton production for an initial short period
C) make no difference to phytoplankton production
D) be toxic to phytoplankton production
E) All of these are false; this experiment has never been tried.

Question 45

The most common nutrient that limits coastal productivity is ________.

A) oxygen
B) phosphate
C) nitrate
D) carbon
E) iron

Question 46

In temperate waters, the timing of the phytoplankton bloom is influenced by ________.

A) light intensity
B) inorganic nutrient concentrations
C) stability of the water column
D) zooplankton abundance
E) All of these are correct.

Question 47

A food web is ________.

A) a net for trapping marine organisms
B) a plan of interactive food chains and energy
C) an inverse trophic pyramid
D) used only with herring life histories
E) a diagram of an organism's life history

Question 48

Krill is the common name for copepods.

Question 49

An increase in the chlorophyll a content of a seawater sample with time yields a measurement of ________.

A) change in the species of phytoplankton in the sample
B) gross production of organic carbon
C) plant respiration
D) net production of organic carbon
E) decomposition of plant cells

Question 50

There is less biomass per unit volume available for harvesting in the open ocean, as compared to upwelling and coastal zones, because ________.

A) there are less nutrients
B) there is less oxygen
C) the salinity is greater
D) the temperature is lower
E) All of these are correct.

Question 51

In a simple food chain with 10-percent efficiency, a net primary production rate at the first trophic level is 10,000 units. How many units are available to the fourth trophic level?

A) 1000
B) 100
C) 10
D) 1
E) 0.1

Question 52

If the net primary production in a region is continually consumed by herbivores, the standing stock ________.

A) increases
B) decreases
C) does not change
D) increases, decreases, or does not change depending on the time of year
E) increases, decreases, or does not change depending on the nutrients present

Question 53

At higher and higher trophic levels, there are usually ________ and ________ animals.

A) fewer; smaller
B) fewer; larger
C) more; smaller
D) more; larger
E) None of these is correct; there is no change in number or size.

Question 54

Sargassum is the only large planktonic seaweed.

Question 55

The Redfield Ratio is ________.

A) N:C:P 106:16:1
B) P:C:N 106:16:1
C) C:P:N 106:16:1
D) C:N:P 106:16:1
E) P:N:C 106:16:1

Question 56

Which compound does not serve as a pigment in phytoplankton?

A) chlorophyll c
B) chlorophyll a
C) fucoxanthin
D) hemoglobin
E) phycoerythrin

Question 57

The coccoliths on the outside of coccolithophores are made of silica.

Question 58

Net plankton are larger than nannoplankton.

Question 59

If baleen whales eat krill that eat diatoms, krill represents the ________ trophic level.

A) first
B) second
C) third
D) fourth
E) fifth

Question 60

The period of highest productivity in polar areas is ________.

A) summer
B) winter
C) spring
D) fall
E) Productivity is similar in all seasons.

Question 61

Diatoms are able to ________.

A) form chains to help floating
B) store oil to reduce their density
C) produce two flagella that provide motility and reduce sinking
D) form chains to help floating and store oil to reduce their density
E) form chains to help floating, store oil to reduce their density, and produce two flagella that provide motility and reduce sinking

Question 62

The most abundant phytoplankton in the open ocean is the cyanobacterium Prochlorococcus.

Question 63

Viral abundance is strongly correlated with plankton biomass.

Question 64

Some ctenophores are herbivores while others are carnivores.

Question 65

All harmful algal blooms are caused by dinoflagellates.

Question 66

Red tides may or may not be poisonous to other marine organisms.

Question 67

Cyanobacteria are one of only a few organisms able to use nitrogen gas to make organic matter.

Question 68

Which organisms are members of the holoplankton?

A) foraminiferans
B) pteropods
C) comb jellies
D) All of these are correct.
E) None of these is correct.

Question 69

DOM or dissolved organic matter is largely unused by other organisms.

Question 70

Holoplankton spend only their larval stages in the plankton.

Question 71

Populations of zooplankton can ________.

A) accumulate at water-layer density boundaries
B) move toward the sea surface at night
C) reflect sound waves
D) accumulate at water-layer density boundaries and reflect sound waves
E) accumulate at water-layer density boundaries, move toward the sea surface at night, and reflect sound waves

Question 72

Dinoflagellates and coccolithophores belong to the ________.

A) phytoplankton
B) zooplankton
C) benthos
D) nekton
E) decomposers

Question 73

Some phytoplankton species migrate as much as 500 m vertically every day.

Question 74

Comb jelly is another name for jellyfish.

Question 75

Archaea are found only in physically extreme environments such as hydrothermal vents.

Question 76

The dominant phytoplankton in the open ocean are members of the picoplankton.

Question 77

Dinoflagellates are known for ________.

A) producing toxins that can be lethal to humans
B) their ability to glow with bioluminescence
C) their formation of bottom sediments
D) producing toxins that can be lethal to humans and their ability to glow with bioluminescence
E) producing toxins that can be lethal to humans, their ability to glow with bioluminescence, and their formation of bottom sediments

Question 78

Autotrophic organisms are ________.

A) able to chemosynthesize
B) the base of the food web
C) able to photosynthesize
D) All of these are correct.
E) None of these is correct.

Question 79

All phytoplankton are capable of photosynthesis.

Question 80

Which is not a member of the zooplankton?

A) a copepod
B) an arrow worm
C) a fish egg
D) a diatom
E) a jellyfish