A
soda lake or
alkaline lake is a
lake on the strongly
alkaline side of neutrality (in other words, a
pH value above 7, typically between 9 - 12). They are characterized by high concentrations of
carbonate salts, typically
sodium carbonate (and related salt complexes), giving rise to their alkalinity. In addition, many soda lakes also contain high concentrations of
sodium chloride and other dissolved
salts, making them
saline- or
hypersaline lakes as well. High pH and salinity often coincide, because of how soda lakes develop (see "Geology, geochemistry and genesis"). The resulting hypersaline and highly alkalic soda lakes are considered some of the most extreme aquatic environments on Earth.