Mono Lake

Mono Lake
Mono Lake
Coordinates	38°0′N 119°0′W / 38.000°N 119.000°W
Type	Hypersaline; Monomictic
Primary inflows	Owens River
Primary outflows	Aquaduct; Evaporation
Basin countries	USA (California)
Max. length	~7.5 km
Max. width	~7.5 km
Surface area	180 km²
Average depth	43 m
Water volume	2.97 km³
Shore length1	~25 km
Surface elevation	1945 m
Islands	Negit Island; Paoha Island
	1 Shore length is not a well-defined measure.

Mono Lake is an alkaline and hypersaline lake in California, United States that is a critical nesting habitat for several bird species and is one of the most productive ecosystems in North America^{[citation needed]}.

Geology

Mono Lake is likely the oldest lake in the US formed at least 760,000 years ago dating back to the Long Valley eruption. Sediments located below the ash layer hint that Mono Lake could be a remnant of a larger and older lake that once covered a large part of Nevada and Utah, making it among the oldest lakes in North America.

Mono lake is a terminal lake in a watershed fed from melting runoff with no outlet. Dissolved salts in the runoff thus remain in the lake and raise the pH and the salt concentration.

Mono Lake is in a geologic active area at the north end of the Mono-Inyo Crater volcanic chain of the Long Valley Caldera. The geological activity is caused by faulting at the base of the Sierra Nevada, and is associated with the crustal stretching of the Basin and Range Province.

Volcanic activity continues in the Mono Lake vicinity: the most recent eruption occurred 250 years ago at Negit Island in Mono Lake. Panum Crater (on the south shore of the lake) is an excellent example of a combined rhyolite dome and cinder cone.

Ecology

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 aqueduct system into the Mono Basin, diverting water that would otherwise have entered Mono Lake. The water surface area was 54,924 acres in 1941. Water diversion soon rapidly reduced the surface area to 37,688 acres by 1982, resulting in a loss of nearly 27 square miles of lake area.

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 and forcing them to abandon the island.

In 1976 University of California, Davis graduate student David Gaines earned his master's degree studying the Mono Lake ecosystem and was instrumental in alerting the public of the effects of the lower water level. Gaines formed the Mono Lake Committee in 1978 and joined up with the Audubon Society to fight a now famous court battle to protect Mono Lake through state public trust laws. Despite these efforts, 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 and as of Aug 2006 it was at 6385 feet (1945 m)^[1]. The goal is to have lake level rise to 6392 feet above sea level, a goal made more difficult during years of drought in the American West.

The lake contains approximately 280 million tons of dissolved salts, with the salinity varying on the amount of water in the lake at any given time. Before 1941, the salinity was approximately 50 grams per liter (g/l) (compared to a value of 31.5 g/l for the world's oceans). In 1982, when the lake reached its lowest level, the salinity had nearly doubled to 99 g/l. In 2002 it was measured at 78 g/l and is expected to stabilize at an average 69 g/l as the lake replenishes over the next 20 years.

The hypersalinity and high alkalinity (pH=10 or equivalent to 2.5 grams of NaOH per liter of water^[2]) of the lake, means that no fish are native to the lake. An attempt by the California Department of Fish and Game to stock the lake failed. The lake is famous for the Mono Lake brine shrimp, Artemia monica, a tiny species of brine shrimp, no bigger than a thumbnail, that are found nowhere else on earth. During the warmer summer months, an estimated 4-6 trillion brine shrimp inhabit the lake. The brine shrimp feed on microscopic planktonic algae which reproduce rapidly during winter and early spring after winter runoff brings nutrients to the surface layer of water. By March the lake is "as green as pea soup" with photosynthesizing algae.^[3] Brine shrimp has no food value for humans, but is a staple for birds of the region. Also an important food source, alkali flies ("Ephydra hians") live along the shores of the lake and walk underwater encased in small air bubbles to graze and to lay eggs. The whole food chain of the lake is based on the high population of single-celled algae present in the warm shallow waters.

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 avocets, 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 phalaropes and red-necked phalaropes arrive from their nesting grounds, and feed until they continue their migration to South America or the tropical oceans respectively.

In addition to migratory birds, a few species spend several months to nest at Mono Lake. Mono Lake is the second largest nesting population of California gulls, second only to the Great Salt Lake in Utah. After abandoning the landbridged Negit Island in the late 70s, California gulls have moved to some nearby islets and have established new, if less protected nesting sites. Cornell University and Point Reyes Bird Observatory have continued the study of nesting populations on Mono Lake that was begun over 20 years ago. Snowy Plovers also arrive at Mono Lake each spring to nest along the remote eastern shores.

In Mark Twain's Roughing It (1872), chapter 38 and chapter 39 provide a humorous but informative early description of Mono Lake in its natural condition in the 1860's.

The general appearance of the lake and surrounding mountains circa 1973 can also be seen in the film, High Plains Drifter.

Native people of Mono Lake

File:Captain John.jpg

Captain John. Leader of the Yosemite-Mono Lake Paiutes

The early people of Mono Lake were called the Kutzadika'a who were the Yosemite-Mono Lake Paiutes. Mono Lake Paiutes cultivated alkali fly larvae called kutsavi in their language. Mono Lake was also referred to as Teniega Bah. The origin of the term "Mono Lake" is unknown^[4]. Apparently, "Mono" is a Yokut term for "fly eater". The Kutzadika'a did not use the term "Mono".

During early contact the first known chief was Captain John. He was also referred to by the Paiute names of Shibana or Poko Tucket. Captain John was the son of another Paiute named the older Captain John.

The Yosemite-Mono Lake Paiutes would also camp yearly at Hetch Hetchy, Yosemite Valley, and along the Merced River to gather acorns and different plant species.

Important species residing in Mono Lake

Alkali fly (Ephydra hians)
Brine shrimp (Artemia monica)
California gull (Larus californicus)

References

^ "Monthly Lake Levels". Mono Lake Committee. Retrieved 2004. {{cite web}}: Check date values in: |accessdate= (help)
^ "Living in an Alkaline Environment". Retrieved 2004. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |Work= ignored (|work= suggested) (help)
^ "Mono Lake". Ecoscenario. Retrieved 2007-01-23.
^ "Kutzadika'a People". Mono Lake Committee. Retrieved 2006-04-02.

External links

[1] "Monthly Lake Levels". Mono Lake Committee. Retrieved 2004. {{cite web}}: Check date values in: |accessdate= (help)

[2] "Living in an Alkaline Environment". Retrieved 2004. {{cite web}}: Check date values in: |accessdate= (help); Unknown parameter |Work= ignored (|work= suggested) (help)

[3] "Mono Lake". Ecoscenario. Retrieved 2007-01-23.

[4] "Kutzadika'a People". Mono Lake Committee. Retrieved 2006-04-02.

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