Which one of the following statements with regard to growth of coral reefs is not correct?

Coral reefs are highly sensitive marine organisms with specific environmental requirements. Statement 1 is incorrect because reef-building corals are stenohaline and cannot survive in freshwater; they require high salinity levels, typically between 30 and 42 parts per thousand [4]. Freshwater influx from rivers can lead to coral fatality. Statement 2 is correct as the optimal temperature for growth is generally between 23°C and 29°C, though they can survive in a slightly broader range above 20°C [2]. Statement 3 is correct because most reef-building corals are restricted to shallow waters, usually less than 50 meters deep, to ensure sufficient light penetration. Statement 4 is correct as corals maintain a symbiotic relationship with zooxanthellae algae, which require plenty of sunlight for photosynthesis to provide the coral with essential nutrients and energy [4].

Sources

1. [2] Environment and Ecology, Majid Hussain (Access publishing 3rd ed.) > Chapter 4: BIODIVERSITY > corAl reefs. > p. 54
2. [4] https://oceanservice.noaa.gov/facts/coralwaters.html
3. [1] Certificate Physical and Human Geography , GC Leong (Oxford University press 3rd ed.) > Chapter 11: Islands and Coral Reefs > Coral Reefs > p. 99
4. [3] Environment, Shankar IAS Acedemy .(ed 10th) > Chapter 4: Aquatic Ecosystem > 4.9. CORAL REEFS > p. 50