Question

Three water bodies were tested for the salinity of the water. Waterbody X showed salt concentration as 3 parts per thousand and Y showed 35 parts per thousand and Z showed 110 parts per thousand salinity. Select the correct option regarding this.
A. X can be a lagoon
B. Y can be sea
C. Z can be an inland river
D. None of these

Answer 1

Salinity refers to the concentration of salts in water. Lagoons have the highest salinity, followed by seawater and inland waters.

Complete answer: Water bodies play an important role in salinity (salt concentration). It is necessary to maintain the aquatic animals. For the survival of aquatic animals, the chemical composition and pH of the water is very crucial. The concentration of salt is measured as salinity in parts per thousand. The salt concentration is less than five parts in inland waters, 30-35 in the sea and > 100 in some hypersaline lagoons. Some organisms are tolerant to a wide range of salinities (euryhaline) but others are restricted to a narrow range (stenohaline). Many freshwater animals cannot live for long in seawater and vice versa because of the osmotic problems, they would face. Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it. Salts are compounds like sodium chloride, magnesium sulphate, potassium nitrate and sodium bicarbonate which dissolve into ions. Moreover, Seawater typically has a mass salinity of around 35 g. where rivers enter the ocean, lower salinity is typically near coasts. Add to this, evaporation of seawater and formation of sea ice both increase the salinity of the sea.
Therefore, option B is the correct answer.

Note: On average, seawater has salinity 35 parts per thousand. It means that for every 1 litre (1000 ml) of seawater there are 35 grams of salt (mostly, but not completely sodium chloride) dissolved in it. A lagoon is a body of water separated from larger bodies of water by a natural barrier. Lagoons are separated from larger bodies of water by sandbars, barrier reefs, coral reefs, and other natural barriers.