Regional distribution of water salinity across the oceans

  • Indian Ocean: The average salinity of the Indian Ocean is 35 parts per thousand . The low salinity is observed in the Bay of Bengal due to the influx of river water by the river Ganga. On the other hand, the Arabian Sea shows higher salinity due to high evaporation and a low influx of freshwater.
  • Pacific Ocean: The salinity variation in the Pacific Ocean is mainly due to its shape and larger areal extent.
  • Atlantic Ocean: The salinity in the Atlantic ocean varies between 20 to 37 parts per thousand according to the location.
    • For example, Near the equator, there is heavy rainfall, high relative humidity, cloudiness and calm air of the doldrums.
    • Whereas, The polar areas experience very little evaporation and receive large amounts of freshwater from the melting of ice. This leads to low levels of salinity, ranging between 20 and 32 parts per thousand
  • North Sea: In spite of its location in higher latitudes, it records higher salinity due to more saline water brought by the North Atlantic Drift.
  • The Mediterranean Sea: The Mediterranean Sea records higher salinity due to high evaporation. Surface waters average about 38 parts per thousand in this sea
  • The Baltic Sea: Baltic Sea records low salinity due to influx of river waters in large quantity, averaging around 35 parts per thousand
  • The Black Sea: Salinity in the Black Sea is very low due to the enormous freshwater influx by rivers, averaging around 13–23 parts per thousand