Mono Lake

From Wikipedia, the free encyclopedia

 This article needs additional citations for verification.
Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (November 2007)
Mono Lake
Mono Lake - Satellite photo
Satellite photo
Location Mono County, California
Coordinates 38.016506° N 119.008999° WCoordinates: 38.016506° N 119.008999° W
Lake type Hypersaline
Monomictic
Primary inflows Owens River
Primary outflows Aqueduct
Evaporation
Basin countries United States
Max. length ~7.5 km (4.7 mi)
Max. width ~7.5 km (4.7 mi)
Surface area 180 km² (69 mi²)
Average depth 17 m (57 ft)
Max. depth 48 m (159 ft)
Water volume 2.97 km³ (0.71 mi³)
Shore length1 ~25 km (15.5 mi)
Surface elevation ~1,945.8 m (6,383.9 ft)
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[1] and is an unusually productive ecosystem.[2]

Contents

[edit] Geology

Showing nearby Lake Tahoe and Yosemite National Park
Showing nearby Lake Tahoe and Yosemite National Park

Mono Lake is believed to have 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 geologically 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.

[edit] Conservation efforts

South Tufa in 1981
South Tufa in 1981
Main article: California Water Wars

In order to provide resources for the growing Los Angeles area, water was diverted from the Owens River. In 1941 the Los Angeles Department of Water and Power extended an aqueduct system into the Mono Basin So much water was diverted that evaporation soon exceeded inflow and the surface level of Mono Lake fell rapidly. By 1982 the lake was reduced to 37,688 acres (152.5 km²) having lost 31 percent of its 1941 surface area. As a result alkaline sands and once-submerged tufa towers became exposed and Negit Island became landbridged exposing the nests of gulls to predators (chiefly coyotes) and forcing the breeding colony to abandon the site.

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 with the Audubon Society to fight a now famous court battle to protect Mono Lake through state public trust laws. While these efforts have resulted in positive change the surface level is still below historic levels and exposed shorelines are a source of significant alkali dust during periods of high wind.

Owens Lake, which once sustained a healthy ecosystem, is now a dry lake bed during dry years due to water diversion. Mono Lake was spared this fate when the California State Water Resources Control Board issued an order to protect Mono Lake and its tributary streams on September 28, 1994. Since that time, the lake level has steadily risen. In 1941 the surface level was at 6,417 feet (1,956 m) above sea level and as of August 2006 it was at 6,385 feet (1,946 m).[3] The lake level of 6,392 feet (1,948 m) above sea level is the goal, a goal made more difficult during years of drought in the American West.

Mono Lake from Mount Dana Summit
Mono Lake from Mount Dana Summit
South Tufa Area, Mono Lake
South Tufa Area, Mono Lake

[edit] Limnology

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 January 1982, when the lake reached its lowest level of 6,372 feet (1,942 m), 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.[4]

An important aspect of the end of water diversions was an onset of "meromixis" in Mono Lake.[5] Prior to the end of water diversions, Mono Lake was typically "monomictic," which means that at least once each year the deeper waters and the shallower waters of the lake mixed thoroughly, thus bring oxygen and other nutrients to the deeper waters. In meromictic lakes, the deeper waters do not undergo this mixing. In meromictic lakes, the deeper layers are more saline than the water near the surface, and are typically nearly devoid of oxygen. As a result, meromixis greatly changes a lake's ecology.

Mono Lake has undergone meromictic periods prior to the one commencing in 1994, and this most recent meromictic period brought on by the end of water diversions ended by 2004.[6]

[edit] Ecology

The hypersalinity and high alkalinity (pH=10 or equivalent to 2.5 grams of NaOH per liter of water[7]) 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.[8] 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 a site of international importance by the Western Hemisphere Shorebird Reserve Network.[9] 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, Killdeer and sandpipers. Over 1.5 million Eared Grebes and phalaropes use Mono Lake during their long migrations.

Exposed tufa towers in the lake
Exposed tufa towers in the lake

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.[1]

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 1970s, 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.

[edit] Important species residing in Mono Lake

Lake alkali flies
Lake alkali flies
Larus californicus
Larus californicus

[edit] Native people of Mono Lake

Captain John. Leader of the Yosemite-Mono Lake Paiutes
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 foraged alkali fly larvae[citation needed], called kutsavi in their language. Mono Lake was also referred to as Teniega Bah. The origin of the term "Mono Lake" is unknown.[10] 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.

[edit] Cultural history

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 1860s.

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

The Diver, a photo taken by Storm Thorgerson for Pink Floyd's album Wish You Were Here, features what appears to be a man diving into a lake, creating no ripples. The photo was taken at Mono Lake, and the tufa towers are a prominent part of the landscape. The effect was actually created when the diver performed a handstand underwater until the ripples dissipated.

Cinderella filmed the iconic power-ballad "Don't Know What You Got (Till It's Gone)" at this scenic spot.

[edit] See also

[edit] References

  1. ^ a b Birds of the Basin: the Migratory Millions of Mono. Mono Lake Committee. Retrieved on 2007-05-12.
  2. ^ Carle, David (2004). Introduction to Water in California. Berkeley: University of California Press. 
  3. ^ Monthly Lake Levels. Mono Lake Committee. Retrieved on 2004.
  4. ^ Mono Lake FAQ. Mono Lake Committee. Retrieved on 2007-05-12.
  5. ^ Jellison, R., Romero, J., and Melack, J. M. (1998). "The onset of meromixis in Mono Lake: unintended consequences of reducing water diversions," Limnology and Oceanograph Vol. 3, No. 4, pp. 704-711.
  6. ^ Jellison, R. and Roll, S. (2003). "Weakening and near-breakdown of meromixis in Mono Lake," unpublished; online version retrieved Feb. 8, 2008.
  7. ^ Living in an Alkaline Environment. Retrieved on 2004.
  8. ^ Mono Lake. Ecoscenario. Retrieved on 2007-01-23.
  9. ^ Western Hemisphere Shorebird Reserve Network. Retrieved on 2008-01-19.
  10. ^ Kutzadika'a People. Mono Lake Committee. Retrieved on 2006-04-02.

[edit] External links

Wikimedia Commons has media related to: