Birkat asch-Schams
| Solar Lake | ||
|---|---|---|
| Geographical location | Egypt , Red Sea | |
| Tributaries | Gulf of Aqaba | |
| Location close to the shore | Eilat | |
| Data | ||
| Coordinates | 29 ° 25 '20.5 " N , 34 ° 49' 47.9" E | |
|
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| Altitude above sea level | near sea level | |
| surface | 0.6 ha | |
| length | 140 m | |
| width | 50 m | |
| volume | 10,244 m³ | |
| Maximum depth | 4-6 m | |
| Middle deep | 1.7 m | |
|
particularities |
Salt lake / lagoon . Highest water temperatures of a salt lake on earth |
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The Birkat asch-Schams (German sun lake , Arabic بركة الشمس Birkat asch-Schams ), also known as Solar Lake , is a salt water lake at the end of the Red Sea in Egypt , which, due to its special location and high salt content,actslike a solar collector and generates the highest water temperatures of 60.5 ° C have so far been measured in a salt lake on earth. This lake, which has existed for around 4600 years, has special hydrographic , chemical and biological properties, which are now being researched with the aim of developing new methods for solar hot water and electricity generation.
environment
The salt lake is located about 18 km south of Eilat on the Sinai Peninsula in Egypt in the desert near the border with Israel . It is a narrow lagoon that has been separated from the Red Sea by sediments. It emerged from a bay in the Red Sea between two rocky headlands, which was separated from the Red Sea by sediments deposited near the coast. The lake is about 140 meters long, 50 meters wide and 4 to 6 meters deep. The salt water of the Gulf of Aqaba , which seeps into the lake through a 60-meter-wide dam, evaporates , increasing the salt concentration and forming and depositing salt crystals. This gives the water a hyaline appearance. In this salty environment with 320 days of sunshine a year, rare stromatolites form .
Due to the influence of the sun and the associated evaporation of water, an extremely high water temperature develops, combined with a high salt content. The extreme salinity of the Solar Lake of 8 percent is twice as high as the average salinity of the world's oceans. In this lake the stromatolites grow extremely slowly. As a result of solar radiation and solar energy, crystals form in the salt water, the so-called monohydrocalcites and other carbonates , which are deposited in the form of mats with a thickness of about one meter. These environmental conditions are the prerequisite for the formation of stromatolites in connection with cyanobacteria .
At night, the near-surface waters of the lake are brushed by the cold winds of the desert and the warm water loses temperature. The stratification of the water creates a strong temperature gradient of up to 18 ° C per meter. The salt layers absorb solar energy during the day and accumulate it. As a result of this effect, temperatures of up to 60.5 ° C and salt contents of up to 18% develop in the Solar Lake. The temperature of 60.5 ° C was measured at a depth of 2.5 to 3 meters and 40 ° C at a depth of 5 meters.
The exact heating mechanism is described in more detail in the article Solar Pond .
Creature
A carpet of cyanobacteria , sulfur bacteria and diatoms formed in shallow areas of the lake . Plaster of paris and oxygen-free mud have formed in the middle of the carpet . Few organisms can survive in this extreme environment . There are tiny beetles and crabs, flatworms and eyelashes . The saline shrimp live in open places and in lower elevations in the lake . These organisms built glycerine into their cells for their survival and, after they die, form carbonate-rich biogenic deposits.
Use of the effects for solar energy technology
The effect occurring in the Solar Lake was researched and experimented with, with the aim of making the effects usable for technical applications in the form of solar heat storage, so-called solar ponds .
- In Israel, so-called mini OTEC ( Ocean Thermal Energy Conversion ) turbines have been developed that use the extreme temperature gradient in the salt lake to generate electricity.
- An engineer in New Mexico has patented a gel-based Solar Pond (German: Solarbassin ) that stores heat and is able to boil water after a few months of storage. There is also a solar pool in New Jersey to generate hot water.
In the opinion of researchers, these effects could well form a viable perspective for energy generation in the future if further research is carried out and methods are developed that can be economically implemented.
Individual evidence
- ^ A b c Yehuda Cohen, Wolfgang E. Krumbein et al .: Solar Lake (Sinai). 1. Physical and chemical limnology. P. 7 Available online ( memento of the original from July 20, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 2.5 MB), accessed on February 7, 2010 (English)
- ↑ a b c d Solar Lake by Dave Grant ( memento of the original from January 31, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed on February 7, 2010
- ↑ Bo Barker Jorgensen, Yehuda Cohen: Solar Lake (Sinai). 5. The sulfur cycle of the benthic cyanobacterial mats available online ( Memento of the original from July 20, 2011 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 1.2 MB), accessed on February 7, 2010 (English)
Web links
- Gabrielle Bonnet: De mystérieux lacs salés? (French)
- Wolfgang E. Krumbein: Biogenic monohydrocalcite spherules in lake sediments of Lake Kivu (Africa) and the Solar Lake (Sinai). Sedimentology 22/1975. P. 631–634 Available online (English)
- Lake ecosystems supported by solar-power pond (English)
- Andreas Teske, Niels B. Ramsing, Kirsten Habicht et al. (1998): Sulfate-Reducing Bacteria and Their Activities in Cyanobacterial Mats of Solar Lake (Sinai, Egypt). American Society for Microbiology available online (English; PDF; 1.5 MB)