Microbial Life > Topics of Interest > About Mono Lake

Mono Lake

Created by Sarah Bordenstein, Marine Biological Laboratory

Mono Lake, the oldest lake in North America, is naturally hypersaline and alkaline. It is a terminal lake, meaning it has no outlet. Water entering the lake from Eastern Sierra streams leaves only via evaporation, resulting in high concentrations of salts and minerals being left behind. In addition, the City of Los Angeles- over 300 miles away- began diverting water from the Mono Basin in 1941, cutting the lake volume in half. This doubled its alkalinity and salinity. An extended court fight has since reduced the amount of water taken from the basin and the lake is slowly recovering. Mono Lake, two and half times as salty and 80 times as alkaline as the ocean, remains an "extreme environment" with a thriving community of halophiles and alkaliphiles. Very few animals live in the waters of Mono Lake, but those which do may occur in vast numbers - why might this be? The lake is home to a special species of Artemia and the alkali fly - the pupal cases of which form the dark desposits around the margins of the lake.

The geology of Mono Lake is of particular interest to scientists searching for clues about life on other planets, such as Mars. Mono Lake has become known for its unusual limestone towers- revealed by the decline in water level and known to extend up to 12 feet. Tufa are towers of calcium carbonate created underwater by the chemical reaction of calcium from fresh water springs with carbonates of the alkaline lake. The rapid precipitation of minerals entombs microorganisms within the towers, leaving behind a microbial fossil record. This is significant to understanding how and where life may have originated and specifically if it would survive passage through space because meteorites from Mars have been found to contain carbonate globules similar to those of the Mono Lake tufa. Scientists hope to apply knowledge gained from analyzing the tufa microfossils to the search for signs of extraterrestrial life.

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