Mono Lake

Mono Lake lies within the Mono Basin, an endorheic basin with no outlet to the ocean. Dissolved salts in the runoff thus remain in the lake, raising the water's pH and salt concentration. The tributaries of Mono Lake include Lee Vining Creek, Rush Creek and Mill Creek which flows through Lundy Canyon. Geological forces formed the basin over the last five million years: basin and range crustal stretching and associated volcanism and faulting at the base of the Sierra Nevada. Prominent shore lines of Lake Russell, called strandlines by geologists, can be seen west of Mono Lake. The area around Mono Lake is currently geologically active. Volcanic activity is related to the Mono–Inyo Craters: the most recent eruption occurred 350 years ago, resulting in the formation of Paoha Island. Panum Crater (on the south shore of the lake) is an example of a combined rhyolite dome and cinder cone. ==Tufa towers==

Many columns of limestone rise above the surface of Mono Lake. These limestone towers consist primarily of calcium carbonate minerals such as calcite (CaCO3). This type of limestone rock is called tufa, a term for limestone that forms at low to moderate temperatures. Tufa tower formation Mono Lake is a highly alkaline lake, or soda lake. Alkalinity is a measure of how many bases are in a solution, and how well the solution can neutralize acids. Carbonate (CO32-) and bicarbonate (HCO3−) are both bases. Hence, Mono Lake has a very high content of dissolved inorganic carbon. Through supply of calcium ions (Ca2+), the water will precipitate carbonate-minerals such as calcite (CaCO3). Subsurface waters enter the bottom of Mono Lake through small springs. High concentrations of dissolved calcium ions in these subsurface waters cause huge amounts of calcite to precipitate around the spring orifices. The tufa originally formed at the bottom of the lake. It took many decades, or even centuries, to form the well-known tufa towers. When lake levels fell, the tufa towers rose above the water surface and stand as the pillars seen today (see Mono lake#Lake Level History for more information). Tufa morphology Description of the Mono Lake tufa dates back to the 1880s, when Edward S. Dana and Israel C. Russell made the first systematic descriptions of the Mono Lake tufa. • Lithoid tufa - massive and porous with a rock-like appearance • Dendritic tufa - branching structures that look similar to small shrubs • Thinolitic tufa - large, well-formed crystals of several centimeters Over time, many hypotheses have been developed regarding the formation of the large thinolite crystals (also referred to as glendonite) in thinolitic tufa. It was relatively clear that the thinolites represented a calcite pseudomorph after some unknown original crystal. Ikaite, or hexahydrated CaCO3, is metastable and only crystallizes at near-freezing temperatures. It is also believed that calcite crystallization inhibitors, such as phosphate, magnesium, and organic carbon, may help stabilize ikaite. When heated, ikaite breaks down and becomes replaced by smaller crystals of calcite. In the Ikka Fjord of Greenland, ikaite was also observed to grow in columns similar to the tufa towers of Mono Lake. This has led scientists to believe that thinolitic tufa is an indicator of past climates in Mono Lake because they reflect very cold temperatures. Tufa chemistry Russell (1883) studied the chemical composition of the different tufa types in Lake Lahontan, a large Pleistocene system of multiple lakes in California, Nevada, and Oregon. Not surprisingly, it was found that the tufas consisted primarily of CaO and CO2. However, they also contain minor constituents of MgO (~2 wt%), Fe/Al-oxides (.25-1.29 wt%), and PO5 (0.3 wt%). ==Climate==

The limnology of the lake shows that it contains approximately 280 million tons of dissolved salts, with salinity varying with the amount of water in the lake at any given time. Before 1941, average 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 , 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 of 69 g/L as the lake replenishes over the next 20 years. An unintended consequence of ending the water diversions was the onset of a period of "meromixis" in Mono Lake. In the time before this, 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 bringing oxygen and other nutrients to the deep waters. In meromictic lakes, the deeper waters do not undergo this mixing; the deeper layers are more saline than the water near the surface, and are typically nearly devoid of oxygen. As a result, becoming meromictic greatly changes a lake's ecology. Mono Lake has experienced meromictic periods in the past; the most recent episode of meromixis, brought on by the end of water diversions, commenced in 1994 and ended by 2004. Lake-level history An essential characteristic of Mono Lake is that it is a closed lake, meaning it has no outflow. Water can only escape the lake if it evaporates or is lost to groundwater. This may cause closed lakes to become very saline. The reconstruction of historical Mono Lake levels using carbon and oxygen isotopes has also revealed a correlation with well-documented changes in climate. In the recent past, Earth experienced periods of increased glaciation known as ice ages. This geological period of ice ages is known as the Pleistocene, which lasted until ~11 ka. Lake levels in Mono Lake can reveal how the climate fluctuated. For example, during the Pleistocene, when the climate was colder, the lake level was higher because there was less evaporation and more precipitation. Following the Pleistocene, the lake level was generally lower due to increased evaporation and decreased precipitation associated with a warmer climate. The low point before modern diversions is at elevation , reached in 143 CE. The lowest modern level due to diversions is at , reached in 1980. ==Ecology==

Aquatic life The hypersalinity and high alkalinity (pH=10 or equivalent to 4 milligrams of NaOH per liter of water) of the lake mean that no fish are native to the lake. An attempt by the California Department of Fish and Game to stock the lake failed. The whole food chain of the lake is based on the high population of single-celled planktonic algae present in the photic zone of the lake. These algae 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. The lake is famous for the Mono Lake brine shrimp, Artemia monica, a tiny species of brine shrimp, no bigger than a thumbnail, that is endemic to the lake. During the warmer summer months, an estimated 4–6 trillion brine shrimp inhabit the lake. Brine shrimp have no nutritional value for humans but are a staple for birds in the region. The brine shrimp feed on microscopic algae. Alkali flies, Ephydra hians, live along the lake's shores and swim underwater, encased in small air bubbles, to graze and lay eggs. These flies are an important food source for migratory and nesting birds. Eight nematode species were found living in the littoral sediment: • Auanema spec., which is outstanding for its extreme arsenic resistance (survives concentrations 500 times higher than humans), having three sexes, and being viviparous. • Pellioditis spec. • Mononchoides americanus • Diplogaster rivalis • species of the family Mermithidae • Prismatolaimus dolichurus • 2 species of the order Monhysterida Birds on tufa in the "South Tufa" area. 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. 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. One to two 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. ==History==

towers in Mono Lake; South Tufa (1981). Native Americans The indigenous people of Mono Lake are from a band of the Northern Paiute, called the Kutzadika'a. They speak the Northern Paiute language. The Kutzadika'a traditionally forage alkali fly pupae, called kutsavi in their language. The term "Mono" is derived from "Monachi", a Yokuts term for the tribes that live on both the east and west side of the Sierra Nevada. During early contact, the first known Mono Lake Paiute chief was Captain John. The Mono tribe has two bands: Eastern and Western. The Eastern Mono joined the Western Mono bands' villages annually at Hetch Hetchy Valley, Yosemite Valley, and along the Merced River to gather acorns, different plant species, and to trade. The Western Mono and Eastern Mono traditionally lived in the south-central Sierra Nevada foothills, including Historical Yosemite Valley. Present day Mono Reservations are currently located in Big Pine, Bishop, and several in Madera County and Fresno County, California. Conservation efforts The city of Los Angeles diverted water from the Owens River into the Los Angeles Aqueduct in 1913. In 1941, the Los Angeles Department of Water and Power extended the Los Angeles Aqueduct system farther northward into the Mono Basin with the completion of the Mono Craters Tunnel between the Grant Lake Reservoir on Rush Creek and the Upper Owens River. 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 , 69 percent of its 1941 surface area. By 1990, the lake had dropped 45 vertical feet and had lost half its volume relative to the 1941 pre-diversion water level. As a result, alkaline sands and formerly submerged tufa towers became exposed, the water salinity doubled, and Negit Island became a peninsula, exposing the nests of California gulls to predators (such as coyotes), and forcing the gull colony to abandon this site. In 1974, ecologist David Gaines and his student David Winkler studied the Mono Lake ecosystem and became instrumental in alerting the public of the effects of the lower water level with Winkler's 1976 ecological inventory of the Mono Basin. The National Science Foundation funded the first comprehensive ecological study of Mono Lake, conducted by Gaines and undergraduate students. In June 1977, the Davis Institute of Ecology at the University of California published a report, "An Ecological Study of Mono Lake, California," which alerted California to the ecological dangers posed by the diversion of water from the lake for municipal use. Owens Lake, the once-navigable terminus of the Owens River, which had sustained a healthy ecosystem, is now a dry lakebed during dry years due to water diversions beginning in the 1920s. Mono Lake was spared this fate when the California State Water Resources Control Board (after over a decade of litigation) issued an order (SWRCB Decision 1631) to protect Mono Lake and its tributary streams on September 28, 1994. SWRCB Board Vice-chair Marc Del Piero was the sole Hearing Officer (see D-1631). In 1941 the surface level was at above sea level. As of October 2022, Mono Lake was at above sea level. It has been more difficult during years of drought in the American West. ==In popular culture==

Artwork In 1968, the artist Robert Smithson made Mono Lake Non-Site (Cinders near Black Point) using pumice collected while visiting Mono on July 27, 1968, with his wife Nancy Holt and Michael Heizer (both prominent visual artists). In 2004, Nancy Holt made a short film entitled Mono Lake using Super 8 footage and photographs of this trip. An audio recording by Smithson and Heizer, two songs by Waylon Jennings, and Michel Legrand's Le Jeu, the main theme of Jacques Demy's film Bay of Angels (1963), were used for the soundtrack. The Diver, a photo taken by Aubrey Powell of Hipgnosis for Pink Floyd's album Wish You Were Here (1975), 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. In print Mark Twain's Roughing It, published in 1872, provides an informative early description of Mono Lake in its natural condition in the 1860s. Twain found the lake to be lying "in a lifeless, treeless, hideous desert... the loneliest place on earth." In film A scene featuring a volcano in the film Fair Wind to Java (1953) was shot at Mono Lake. Most of the film High Plains Drifter (1973) by Clint Eastwood was shot on the southern shores of Mono Lake in the 1970s. An entire town was built here for the film, and later removed when shooting was complete. In music The music video for glam metal band Cinderella's 1988 power ballad "Don't Know What You Got ('Till It's Gone)" was filmed by the lake. ==See also==