Biology Test Biology Marine Biology & Aquatic Ecosystems

Question 1

Which zone of the ocean receives enough sunlight to support photosynthesis?

Accepted Answer

Photic (euphotic) zone

Answer

Abyssal zone

Answer

Benthic zone

Answer

Aphotic zone

Question 2

What are the primary producers in most open-ocean (pelagic) ecosystems?

Accepted Answer

Phytoplankton

Answer

Kelp forests

Answer

Zooplankton

Answer

Coral polyps

Question 3

Coral reefs are built primarily by:

Accepted Answer

Colonial cnidarians secreting calcium carbonate skeletons

Answer

Calcareous algae alone

Answer

Sponges depositing silica

Answer

Mollusks forming limestone beds

Question 4

Coral bleaching occurs when corals expel their symbiotic algae (zooxanthellae) due to:

Accepted Answer

Elevated water temperatures and stress

Answer

Excess nutrients

Answer

Low salinity

Answer

Reduced wave action

Question 5

Which physical factor most strongly stratifies the ocean into distinct layers?

Accepted Answer

Temperature and salinity differences (creating density gradients)

Answer

Water pressure

Answer

Current direction

Answer

Dissolved oxygen levels

Question 6

Estuaries are highly productive ecosystems because they receive nutrients from:

Accepted Answer

Both freshwater runoff (rivers) and tidal marine input

Answer

Deep ocean upwelling only

Answer

Volcanic vents

Answer

Offshore kelp beds