Correct option is A
Statement A is Correct:
- Chlorinity refers to the total weight of chloride, bromide, and iodide ions in seawater.
- The average chlorinity of ocean water is 19.2‰, as determined through global oceanographic studies.
- Since salinity is approximately 1.80655 times chlorinity, the average ocean salinity is around 35‰.
Statement B is Correct:
- The highest salinity zones are found in the subtropical high-pressure belts, between 20° and 40° latitudes in both hemispheres.
- These regions have high evaporation rates and low precipitation, leading to higher salinity.
- Example: North Atlantic and South Atlantic Oceans show peak salinity levels in this belt.
Statement D is Correct:
- Isohalines are lines on a map that connect points of equal salinity in the ocean.
- They are similar to contours in topography, showing spatial variation in ocean salinity.
Information Booster:
Why is Salinity High in 20°-40° Latitudes?
- High evaporation due to strong solar radiation.
- Low precipitation due to subtropical high-pressure systems.
- Limited freshwater input as major rivers are located outside this belt.
Why is Salinity Lower at the Equator and Poles?
- Equator:
- Heavy rainfall and river discharge dilute the seawater.
- Example: Amazon, Congo, and Ganges river mouths have low salinity zones.
- Poles:
- Low evaporation rates due to cold temperatures.
- Ice melting lowers salinity in Arctic and Antarctic waters.
Additional Information
Statement C is Incorrect:
- The belt ofhighest salinity is NOT found between 10° and 20°N and S latitudes.
- This region hasinfluence from the Equatorial zone, wherehigher precipitation and river dischargereduce salinity.
- Thecorrect high-salinity belt is 20°–40° N & S.
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