One of the most ancient lakes in North America is found a little over a dozen miles outside Yosemite National Park. But it's not your average lake. Known for tall formations called tufa towers, arriving at the shores of this lake feels a little like arriving on the surface of another planet. Welcome to the natural wonder that is the 1 million-year-old Mono Lake.
While it may look like a desolate place at first glance, Mono Lake is actually a rich and thriving ecosystem.
"Sagebrush, Jeffrey pines, volcanoes, tufa towers, gulls, grebes, brine shrimp, alkali flies, freshwater streams, and alkaline waters comprise an unlikely world at the transition between the Sierra Nevada mountains and the Great Basin desert," according to the Mono Lake Committee. "Embracing 14 different ecological zones, over 1,000 plant species, and roughly 400 recorded vertebrate species within its watershed, Mono Lake and its surrounding basin encompass one of California's richest natural areas."
The lake covers about 65 square miles, and is considered an important breeding ground for gulls as well as an important stop-off for migratory birds. The best guess at age is a minimum of 760,000 years old, but likely the lake formed more than 1 million years ago. The lake is fed by run-off from the Sierras, and has no outlet. Because of this, there's a high concentration of salts and currently the lake is about three times as salty as the ocean.
The chemistry of the lake is the answer behind the strange towers that line its shores.
"Tufa is essentially common limestone," Mono Lake Committee explains. "What is uncommon about this limestone is the way it forms. Typically, underwater springs rich in calcium (the stuff in your bones) mix with lake water rich in carbonates (the stuff in baking soda). As the calcium comes in contact with carbonates in the lake, a chemical reaction occurs resulting in calcium carbonate — limestone. The calcium carbonate precipitates (settles out of solution as a solid) around the spring, and over the course of decades to centuries, a tufa tower will grow. Tufa towers grow exclusively underwater, and some grow to heights of over 30 feet. The reason visitors see so much tufa around Mono Lake today is because the lake level fell dramatically after water diversions began in 1941. "
Those water diversions are a significant part of this lake's story. In order to provide water to Los Angeles, the Department of Water and Power diverted streams that normally fed the lake. The water level of the lake dropped to half its former level in a matter of decades while the salinity doubled. Before diversions began in 1941, the lake was 4.3 million acre-feet in volume, whereas at its lowest point in 1982 it was at 2.1 million acre-feet in volume.
This was a serious issue for the flora and fauna dependent on the lake, and steps were needed to protect a unique and fragile ecosystem. In the last several decades, conservationists have helped to better manage the flow of water to the lake and are slowly returning the lake to its previous levels, which in turn is reducing the salinity and restoring the ecosystem.
As part of the plan to protect the lake, Mono Lake Tufa State Natural Reserve was established in 1984. "The reserve was established to preserve the spectacular 'tufa towers' ... It also protects the lake surface itself as well as the wetlands and other sensitive habitat for the 1-2 million birds that feed and rest at Mono Lake each year."
Not only is the issue of water diversions an issue for the health of the lake, but so too is California's record drought, which has its own serious impact on how much water flows into the lake and how much evaporates.
In June of this year, the LA Times reported, "In recent months, the Department of Water and Power has reduced its take from [Lake] Mono's tributaries by more than two-thirds. Still, the 1-million-year-old lake is within two feet of the level that state officials say threatens the alpine ecosystem at the base of the eastern Sierra Nevada. Unless the region gets a significant amount of rain by the next official water level reading in April, Mono may fall to 6,377 feet in elevation, triggering a halt to any diversions."
The reason for keeping the water levels up isn't only about salinity. We reported earlier in the year that "Any further drop in water level is a frightening prospect for biologists concerned about the well-being of the birds that nest on Negit Island in the middle of the lake. The lower the water drops, the easier it is for coyotes to get out to the island. In 1979, water levels dropped so low that a land bridge leading out to the island broke the surface, and coyotes devastated the nests of gulls. It took 20 years for the birds to return to the island to nest."
Though the many tufa towers are a sign of the lake's low water levels, they are a feature that draws in photographers from around the world. Landscape photographers have created beautiful images capturing the lake's many views, always changing with the weather and light. The reflection of the towers in the water, or their striking contrast against a twilight sky creates an incredible scene. The photos here celebrate the lake's extraordinary and fragile beauty.