Weber State University
Department of Botany
Antelope Island Field Trip
THE GREAT SALT LAKE
Facts: GSL is:
• The 33rd largest lake in the world*
• The 4th largest terminal lake (no outlet to the sea) in the world*
• The largest U.S. lake west of the Mississippi River
• A remnant of Lake Bonneville, a prehistoric freshwater lake that was 10 times larger than GSL.
• About 75 miles long and 28 miles wide and (on average) covers 1,700 square miles
• Has a maximum depth of about 35 feet
• Typically is 3 to 7 times saltier than the ocean
• One of the largest migratory bird magnets in Western North America
* The size of the lake varies because of the amount of inflow and the fact that it is so shallow. At the historic low elevation of 4,191.35 feet in 1963, the lake covered only 950 square miles. The drop of about 8.5 feet in elevation from its historic "average" (1847-2000) surface elevation of 4,200 feet, resulted in a loss of about 44 % in surface area. This would place the size of the lake somewhere about the 12th largest terminal lake in the world rather than 4th. During 1986 and again in 1987, the lake reached an elevation of 4,211.6 feet and had a surface area of around 3,300 square miles. The pumping that took place following the historic high levels reached in 1987 resulted in a large, shallow, saline lake in the west desert as an extension of the Great Salt Lake.
Economic Value of Minerals
The Great Salt Lake contains an estimated 5 billion tons of salt. Each year an additional 2.5 million tons washes in and accumulates due to evaporation. It is estimated that the total value of the salts in the lake reach nearly $90 billion. Yes, $90 x 109. Only in recent decades has this been appreciably touched and currently slightly more is extracted annually from the lake than is wash in. In the last few decades the development of various low-energy solar technologies have combined to make the lake an attractive source of the following: common salt, sodium chloride; potassium sulfate (fertilizer); sodium sulfate (chemicals and medicine); chorine gas (plastics); magnesium sulfate; magnesium metal; and lithium compounds. Industries extracting salt and other minerals from the Great Salt Lake include: Great Salt Lake Minerals and Chemicals, Morton International, Cargill, Akzo Nobel Salts, MagCorp, North American Salt Company, and Mineral Resources International.
Socio-Economic Value of the Biota
The socio-economic value of the marshes sustained by the lake is incalculable.
Value of the Wetlands:
The state of Utah is home to some of the most valuable wetlands in the United States. We are in the flyway for many of the migrating bird species and provide critical wetland ecosystems for many plants and animals. The value of wetlands as a national resource cannot be understated. Over ten years ago, President George Bush (Sr.) established a policy of "No net loss of wetlands." Federal Agencies now spend approximately $800 million a year on wetlands protection and development. Constructed wetlands are a demonstrated effective method to improve water quality. Yet in spite of this, the concept of wetlands is poorly understood by the public and is the subject of diverse opinions among wetland scientists. Furthermore, the majority of wetlands studies have focused on environmental and ecological issues. Less effort has been devoted to assessing, collecting and developing the best technical approaches to mitigate, preserve, enhance and create the value and function of wetlands.
Value of the Brine Shrimp:
The brine shrimp industry on Great Salt Lake began during the 1950’s with harvesting of adult brine shrimp for fish food in the aquarium trade in the U.S. That expanded to many parts of the world and as the aquaculture industry developed large commercial operations, the need for more brine shrimp developed so in the 1970’s the harvesting of cysts commenced. Since the production of brine shrimp cysts is dependent on salinity (if the salinity drops below 10% the cysts lose buoyancy, sink, and are more difficult to harvest) and salinities vary considerably, this industry is faced with many uncertainties. Nevertheless, up to 21 million pounds (gross weight) of cysts in the best years, like 1995-96, 1996-97, and again in 2001-02, are harvested. During other years with much less production much lower quantities are harvested over very few days or weeks.
Other economic value(s):
A very large emerging potential exists for the beta-carotene contained in Dunaliella salina during the summer months when large quantities of these cells accumulate in the very concentrated brines of the solar evaporation ponds of the various salt extraction industries located around or within the lake. Pilot-plant operations exploring the feasibility of such extraction has found that the economics is not favorable currently to develop fully, however, the potential is still there.
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