Caspian Sea
The Caspian Sea, like the Black Sea, Namak Lake, and Lake Urmia, is a remnant of the ancient Paratethys Sea. It became landlocked about 5.5 million years ago due to tectonic uplift and a fall in sea level. During warm and dry climatic periods, the landlocked sea almost dried up, depositing evaporitic sediments like halite that were covered by wind-blown deposits and were sealed off as an evaporite sink when cool, wet climates refilled the basin. (Comparable evaporite beds underlie the Mediterranean.) Due to the current inflow of fresh water, the Caspian Sea is a freshwater lake in its northern portions, and is most saline on the Iranian shore, where the catchment basin contributes little flow. Currently, the mean salinity of the Caspian is one third that of Earth's oceans. The Garabogazköl embayment, which dried up when water flow from the main body of the Caspian was blocked in the 1980s but has since been restored, routinely exceeds oceanic salinity by a factor of 10.
Caribbean Sea
The hydrology of the sea has a high level of homogeneity. Annual variations in monthly average water temperatures at the surface do not exceed . Over the past fifty years the Caribbean has gone through three stages: cooling until 1974; a cold phase with peaks during 1974–1976 and 1984–1986 then; a warming phase with an increase in temperature of per year. Virtually all temperature extremes were associated with the phenomena of El Niño and La Niña. The salinity of seawater is about 3.6% and its density is . The surface water colour is blue-green to green.