Marine Biology Quiz
Questions: 16 · 10 minutes
1. How is a whale shark classified?
As a marine mammal because it is very large
As a bony fish because it breathes through gills
As a cartilaginous fish with a skeleton primarily made of cartilage
As a marine reptile because it swims near the surface
2. A persistent pollutant becomes more concentrated at each successive trophic level. In the same food web, where would the highest concentration usually be expected?
In primary producers at the base of the web
Only in organisms that perform photosynthesis
Equally in every organism regardless of diet
In long-lived predators near the top of the web
3. As seawater absorbs additional carbon dioxide, which paired change is expected?
Lower pH and reduced carbonate-ion availability
Higher pH and lower carbonate-ion availability
Lower pH and greater carbonate-ion availability
Higher pH and greater carbonate-ion availability
4. Which description best defines an estuary?
A coastal body of water where river water mixes with seawater
A freshwater lake periodically reached by ocean spray
A coral lagoon completely isolated from tides and rivers
A deep-ocean area surrounding a hydrothermal vent
5. Two seawater samples have the same salinity but different temperatures. Which sample would generally hold less dissolved oxygen at equilibrium?
The cooler sample, because cold water repels gases
They would necessarily hold identical amounts because their salinity is equal
The cooler sample, because oxygen is converted into salt
The warmer sample, because gas solubility generally decreases as water warms
6. Researchers want to measure how barnacle abundance changes from the low-tide zone to the high-tide zone on a rocky shore. Which approach is most suitable?
Collecting one water sample far offshore
Observing a single barnacle through one tidal cycle
Counting barnacles in quadrats placed along shore-height transects
Recording only the largest organism found on the shore
7. A fishery is accidentally catching sea turtles in its gear. Which change most directly addresses this bycatch problem?
Moving discarded catch to a different part of the vessel
Increasing the time that the gear remains in the water
Using gear modifications that allow turtles to escape
Targeting additional species during the same fishing trip
8. A marine bony fish continually loses water to its salty surroundings. Which response helps it maintain water balance?
Absorbing large amounts of water through its skin
Stopping ion transport across its gills
Producing large volumes of very dilute urine
Drinking seawater and excreting excess salts
9. A mussel on a rocky shore is exposed to air when the tide recedes. Which response best limits water loss?
Extending its feeding structures into the air
Closing its shells tightly
Releasing the water held inside its shell
Detaching so waves can carry it offshore
10. A researcher tests whether added nitrate increases algal growth. Which design best isolates the effect of nitrate?
Keep conditions consistent, vary nitrate levels, and include replicated controls
Use different algal species and temperatures in every container
Measure only the nitrate-treated algae without a comparison group
Give the nitrate treatment more light and compare it with a shaded control
11. Why must dolphins regularly return to the ocean surface?
Their gills function only in oxygen-rich surface water
They must warm their bodies in direct sunlight
They can absorb freshwater only from the air
They breathe atmospheric air with lungs
12. During a prolonged heatwave, a reef-building coral turns pale. What most directly causes this bleaching?
The coral's calcium carbonate skeleton dissolves completely
The coral loses or expels many of its symbiotic algae
The coral stops capturing every type of plankton
The coral is immediately replaced by a sponge colony
13. Which organisms perform much of the photosynthesis that supports open-ocean food webs?
Phytoplankton
Zooplankton
Marine fungi
Deep-sea tube worms
14. Satellite data reveal cool water rising near a coast, followed by increased phytoplankton growth. What most likely explains the increase?
The rising water blocks light and prevents grazing
Upwelling brings nutrient-rich deep water into the sunlit zone
The rising water converts zooplankton into primary producers
Upwelling removes dissolved nutrients from surface water
15. In a Southern Ocean food web, krill are major prey for several baleen whale species. If krill abundance falls sharply, what is the most direct likely effect on those whales?
Immediate conversion from filter feeding to photosynthesis
Reduced access to an important food source
Greater energy transfer from krill to whales
Elimination of competition among krill predators
16. A fish has a dark back and a pale underside. How can this countershading reduce its visibility?
Both surfaces reflect the same amount of light from every direction
The pattern makes the fish resemble a brightly colored reef
The dark back blends with deeper water from above, while the pale belly blends with surface light from below
The pale underside produces light that illuminates the seafloor