Question

From the list given below, identify the organism type in the biological pump that takes up carbon dioxide from the atmosphere into the ocean.

• A. Zooplankton
• B. Fish
• C. Phytoplankton
• D. Radiolarians

Hint:

Remember: Phytoplankton = “plant of the sea,” perform photosynthesis, fix CO$_2$ → biological pump driver.

Answer 1

The Correct Option is C

Step 1: Recall the concept of biological pump.
- The biological pump refers to the process where marine organisms fix atmospheric CO$_2$ and transport it into deeper ocean layers.
Step 2: Identify key organisms.
- Phytoplankton: Photosynthetic organisms; directly absorb CO$_2$ from the atmosphere and form the base of marine food chains.
- Zooplankton and fish: Consumers, they do not fix CO$_2$, instead they respire.
- Radiolarians: Protozoans that build silica shells, but not the primary fixers of CO$_2$.
Step 3: Conclusion.
Hence, phytoplankton are the key organisms responsible for CO$_2$ uptake in the biological pump. Final Answer: \[ \boxed{\text{(C) Phytoplankton}} \]