Q. Consider the following statements:
- The salt concentration is less than 5 parts per thousand in inland waters.
- The organisms that can tolerate a wide range of salinities are called stenohaline.
- Freshwater animals easily survive in sea water for long period.
Which of the above is / are correct?
Answer:
Only 1 and 2
Notes: For aquatic organisms the quality (chemical composition, pH) of water becomes important. The salt concentration (measured as salinity in parts per thousand), is less than 5 in inland waters, 30-35 in the sea and > 100 in some hypersaline lagoons. Some organisms are tolerant of a wide range of salinities (euryhaline) but others are restricted to a narrow range (stenohaline). Many freshwater animals cannot live for long in sea water and vice versa because of the osmotic problems, they would face.