Which ocean is the saltiest?

The Atlantic Ocean is generally considered the saltiest major ocean.

Average surface salinity in the open Atlantic is roughly 33 to 37 parts per thousand, although it changes by location and season. The highest values tend to occur in the subtropics, especially around 25 degrees north and south, where strong evaporation removes water while relatively little rain returns to the surface.

Salinity is not uniform across the entire ocean. Tropical rainfall lowers surface salinity near the equator, while river discharge freshens coastal waters. Melting sea ice can also reduce salinity. Even so, when the major oceans are compared as broad basins, the Atlantic usually has the highest average surface salinity.

The Atlantic's saltier water is important to global ocean circulation. Dense, salty water sinks in the North Atlantic and helps drive the Atlantic Meridional Overturning Circulation, a system that redistributes heat and nutrients around the planet. The Indian Ocean can contain very salty regional waters, but that does not make it the saltiest major ocean overall. Salinity also differs between surface water and deep water, so local exceptions do not overturn the standard quiz answer.