NASA's new Aquarius instrument has produced its first global map of the saltiness (or salinity) of the Earth's ocean surface. Basically, yellow and red indicate areas of higher salinity while blue and purple indicate areas of lower salinity. Black areas are gaps in the data. Average salinity is 35.
For us in Sri Lanka, the most important thing to point out is the sharp contrast between the arid, high salinity Arabian Sea west of India, the result of excessive evaporation, and the low salinity Bay of Bengal to the east which is more dominated by freshwater from the Ganges river and monsoon rains. See what a vital exchange point the southern coast of Sri Lanka forms?