We visited Mono Lake a few years back during a family vacation on the US West Coast. The best time for a visit, especially in the summer, is late in the afternoon because the lighting is better for photography and the temperature is more pleasant. Low angle light makes the beautiful blue-green color of the lake and the tufa towers sticking out of the water even more spectacular.
Unlike most lakes, which are fresh water, the Mono Lake is an enclosed saline lake formed in a low area of the Mono Basin, which is located in the Basin and Range province of the United States. The greatest attraction are the tufa towers, spectacular features in the form spires and rounded knobs rising several feet above lake level.
Tufa is a form of calcium carbonate, and is similar to the stalactites and stalagmites that we enjoy so much in caves. At this location the towers start forming on the bottom of the lake, where fresh water springs rich in calcium mix with the water from the lake, which contains sodium and potassium carbonate in solution. The fresh water is lighter than the saline water of the lake and, as a result, it rises up. As the fresh water rises, the calcium in solution combines with the sodium and potassium dissolved in the lake water and precipitates tufa.
The tufa in the towers is porous, and as more fresh water enters the lake through the springs, it flows through the intricate structure of the pores and when escapes and reaches the lake water, it precipitates more tufa, creating the impressive knobs and spires we see today.
Before 1941 this place looked completely different. About 15,000 years ago the ancient lake had a surface area of almost five times as today and was nearly 800 feet deeper. When initially formed, after the last ice-age, it was fed by glacial meltwater, and later on by five fresh-water streams derived from the snow melt in the Sierra Nevada range. Growing water demands in the city of Los Angeles resulted in the diversion of the fresh water streams 350 miles south. This change had a dramatic effect on the lake’s water level, the salinity and the entire ecosystem. If interested, you can read more on the Mono Lake story here.