Mono Lake is an alkaline and hypersaline lake in California, United States that is critical nesting habitat for several bird species and is one of the most productive ecosystems in North America.
Mono Craters to the right of the image are rhyolitic domes. The dark colored Negit island is of volcanic origin and is somewhat less than 2000 years old. Pahoa Island is the larger and lighter colored island in the lake and was formed 300 years ago from uplift caused by magma movement. Black Point is the remnant of a cinder cone volcano that erupted under water during on of the stands of Lake Russel.
In order to provide water for growing Los Angeles, water was diverted from the Owens River and then from the tributaries that fed Mono Lake (see California Water Wars). In 1941 the city of Los Angeles extended an aquaduct system into the Mono Basin, diverting water that would otherwise have entered Mono Lake.
Enough water was diverted that evaporation soon exceeded inflow and the lake level fell rapidly, exposing alkaline sands and once-submerged tufa towers, and turning Negit Island into a peninsula, exposing the nests of gulls to coyotes.
University of California, Davis graduate student David Gains in 1976 earned his master's degree studying the Mono lake ecosystem and was instrumental in alterting the public of the effects of the lower water level. Efforts have since been made to redivert water back into the lake. However, the lake is still lower than historic levels and exposed shorelines are a source of significant alkali dust during periods of high winds.
Owens Lake, which sustained a similar ecosystem, completely dried up because of water diversions. Mono Lake was spared the same fate on September 28, 1994, when the California State Water Resources Control Board issued an order to protect Mono Lake and its tributary streams. Since that time the lake level has steadily risen; in 1941 the lake level was at 6417 feet above sea level, as of 2002 it was at 6385 feet, and the goal is to have lake level rise to 6392 feet above sea level.
Mono Lake is a vital resting and eating stop for migratory shorebirds and has been recognized as an International Reserve in the Western Hemisphere Reserve Network.
Nearly 2,000,000 waterbirds, including 35 species of shorebirds, use Mono Lake to rest and eat for at least part of the year. Some shorebirds that depend on the resources of Mono Lake include American avocetss, killdeers, and sandpipers. Over 1.5 million eared grebes and phalaropes use Mono Lake during their long migrations.
Late every summer tens of thousands of Wilson's phalaropess and red-necked phalaropess arrive from their nesting grounds, and feed until they continue their migration to South America or the tropical oceans respectively.
The whole food chain of the lake is based on the high population of single-celled algae present in the warm shallow waters.
- Alkali fly (Ephydra hians)
- brine shrimp (Artemia monica)
- California gull (Larus californicus)
