Question

Q. With reference to the conditions required for the formation of Coral Reefs, Which of the following is/are incorrect?

Select the correct answer using the code given below:

• A. 1 and 2 only
• B. 2 and 3 only
• C. 1 and 3 only
• D. 1,2 and 3

Answer 1

The correct option is C 1 and 3 only

Explanation:

Statement 1 is incorrect- Warm water temperature: Corals generally live in water temperatures of 20–32° C.

Statement 2 is correct- Sunlight: Corals need to grow in shallow water where sunlight can reach them. zooxanthellae (algae) needs sunlight for photosynthesis.Corals have a symbiotic relationship with zooxanthellae; they are dependent on algae for food. Hence, corals rarely develop in water deeper than 50 meters.

Statement 3 is incorrect

• Corals need calm water. Area where rivers meet oceans are highly unstable due to continuous movement of water. Corals need saltwater to survive and require a certain balance in the ratio of salt to water. This is why corals don't live in areas where rivers drain fresh water into the ocean
• Saltwater not freshwater: saltwater is essential for corals. Salts extracted from seawater are necessary for the formation of calcareous shells. This is why corals don’t live in areas where rivers drain freshwater into the ocean i.e. the estuaries.

Additional information:

• Clearwater: Corals need clear water so that more sunlight can penetrate through seawater. They don’t thrive well when the water is opaque. Sediment and plankton can cloud water, which decreases the amount of sunlight that reaches the zooxanthellae and adversely affects its growth.
• Abundant Plankton: Phytoplankton is marine seafood. It is essential for the growth of corals.