Upwelling
The major upwellings in the ocean are associated with the divergence of currents that bring deeper, colder, nutrient rich waters to the surface. There are at least five types of upwelling: coastal upwelling, large-scale wind-driven upwelling in the ocean interior, upwelling associated with eddies, topographically-associated upwelling, and broad-diffusive upwelling in the ocean interior.
Soda lake
Soda lakes occur naturally throughout the world (see Table below), typically in arid and semi-arid areas and in connection to tectonic rifts like the East African Rift Valley. The pH of most freshwater lakes is on the alkaline side of neutrality and many exhibit similar water chemistries to soda lakes, only less extreme. 
In order for a lake to become alkalic, a special combination of geographic, geological and climatic conditions are required. First of all, a suitable topography is needed, that limits the outflow of water from the lake. When the outflow is completely prevented, this is called an endorheic basin. Craters or depressions formed by tectonic rifting often provide such topological depressions. The high alkalinity and salinity arise through evaporation of the lake water. This requires suitable climatic conditions, in order for the inflow to balance outflow through evaporation. The rate at which carbonate salts are dissolved into the lake water also depends on the surrounding geology and can in some cases lead to relatively high alkalinity even in lakes with significant outflow.