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NO WAY OUT
Why is Mono Lake water so salty? Mountains
surround Mono Lake forming a closed hydrological
basin—water flows into the lake, but it doesn’t
flow out. The only way for water to leave Mono Lake is
through evaporation. Four vertical feet of water can
evaporate off of Mono Lake during the course of a year,
and without fresh water streams to replace the evaporated
water there would be no lake. Freshwater streams and
underwater springs have brought trace amounts of minerals
into Mono over the eons. Because the lake has no outlet,
it is naturally saline. An estimated 280 million tons of
solids are dissolved within the lake, and it is 2-3 times
saltier than the ocean depending on its water level
fluctuation over the years. Periodic eruptions of
volcanic ash have also added considerably to Mono’s
chemical mix.
GREAT BASIN CHEMISTRY
As with most lakes, Mono Lake has a chemistry unique in all the world. Within Mono’s waters are dissolved sodium salts of chlorides, carbonates and sulfates (Mono Lake has a lot of salt and baking soda in it). In contrast, the Great Salt Lake contains abundant chloride but relatively no carbonates. Mono Lake is also rich in borate and potassium (boron concentrations among the highest ever recorded for a lake). Mono is one of the few remaining inland lakes in the Great Basin, a large geographical region with no outlet to the ocean. Mono Lake, Great Salt Lake in Utah, and Lake Abert in Oregon are the last few large hyper saline lakes in the Great Basin that host productive ecosystems and large numbers of migrating birds.
A SOAP TO BE RECKONED WITH
High concentrations of carbonates in Mono Lake make it very alkaline. The pH of Mono Lake is approximately 10 (this measure of alkalinity is roughly equivalent to household glass cleaner). Because of this high alkalinity,
Mono
Lake water tastes bitter and feels slippery. Some
observers of Mono Lake water claim it feels and behaves a
lot like soapy water (sulfates and carbonates are a
factor). William Brewer no doubt found this to be the
case; however, you may not wish to repeat Mr.
Brewer’s laundry experiment—Mono Lake water has
a high enough pH to deteriorate clothing and footwear
after repeated soakings.
MONO’S SECRET RECIPE
You can make a close approximation of Mono Lake water at home or in the classroom: begin with one gallon of pure water, add 18 tablespoons of baking soda, ten tablespoons of table salt, 8 teaspoons of Epsom salt, and a pinch of borax or laundry detergent (in order to make tufa, just add fresh water containing dissolved calcium chloride). If you wanted to concoct a more accurate approximation of Mono Lake water, you might consider adding trace amounts of strontium, magnesium, calcium, fluoride, arsenic, lithium, iodine, and tungsten. If you really wanted to get picky, you might also throw in an abnormally high amount of the radioisotope carbon-14, a smidgen of uranium, thorium, and plutonium! Beginning to sound dangerous? It’s not--because of extremely low concentrations. But why is plutonium, a man-made radioactive element, even present in Mono Lake at all?
A CHEMICAL JIGSAW PUZZLE
For as much as we understand about Mono Lake’s chemistry, there is still much that we do not.
Temperature, wind, climatic variations, underwater springs, and even biological activity can affect Mono Lake’s chemistry at different depths, locations and seasons. We are only just beginning to understand the more subtle changes in the lake’s chemistry. A USGS scientist who had been studying Mono Lake chemistry for many years once remarked, "Every year there are new surprises." With such a unique chemical signature, Mono Lake will no doubt continue to provoke scientific study.
4/06 Lake Level (feet above the sea): 6383
Predicted Salinity at Current Lake Level (g/l): 80.8
Predicted Current Salinity (%): 8.1
Lake Ph: 9.8
Click here for more statistics!
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