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Ecology

  • Halophiles are a unique set of microorganisms, they can happily grow in high salty concentrations. 

  • Typical examples include hypersaline lakes, such as the Great Salt Lake and the Dead Sea, these will often contain salt levels which are five times greater than the concentration of the ocean (S DasSarma & P DasSarma, 2006).

  • On Earth, halophiles are suited in close proxminity to salt environments. They represent a physiologically,  phylogenetically,  evolutionarily, and ecologically diverse group of organisms.

  • It is important to note, that these type of organsims can live in in hot and cold environments, as well as wet and dry or even alkaline and neutral surroundings.

  • In the phylogenetic tree, halophines are generally distrubuted amoung non-halophiles (Fig. 1).

The Dead Sea

 

  • The Dead Sea is located between Jordan and Israel.

  • The concentraion of salt is almost ten times higher than sea water.

  • Suprisingly the Dead Sea has a large pH range of 5.8 - 6.0.

  • Ideally, this lake is suituated in a very dry climate. It is expected to become drier and smaller in size due to increase levels of greenhouse gases, which in turn increases  the temperature of the water surface (1.5 degrees Celsius.)

  • During rain seasons, algae blooms can form.

  • Surface of the dead sea can often reach: 1,300 feet below sea level.

  • As much as 35% of the water contains dissolved salts

  • Since there are no rivers to drain out the lake to allow fresh water to be added (to regain and control salinity levels) it is become renowned as being the saltiest lake in the world.

  • Therefore, they are given the name “salt loving” from the Greeks due to their exceptional adaptatation

  • It is important to acknowledge that halophiles survive in enviornments where UV radiation is in high doses and nutrients levels are low as well as being adapted to high osmotic pressure in their envirnment.

 

 

How Do Hypersaline Environments Arise?

 

  • The formation of hypersaline environments often are created when the rate of evaporation and the withdrawal of freshwater surpasses the rate of replacement. 

 

 

Halophiles In Space?

 

  • There is some evidience indicating that halophiles could survive up to two weeks in space or even longer. 

  • The nature paper even published an article in 2001 named "The Biopan halophile experiement" showing how in fact isolates of halophiles can be exposed into the earth's orbit during their two week mission. The equipment named Biopan stored and contained  a salt evaporation pond containing varous types of halophiles.   

  • These two halophilic microorganisims "Archael Haloarcula" and "Cyanobacterium" both were isolated from halite evaporite crust. Suprisingly,  these halophilst were highly resistant to the exposure of the vaccum and subsequently to the high levels of UV radiation in outer space. 

  • Would Halophiles be identified in Mars?

 

 

How Do Hypersaline Environments Support The Local Habitats? 

 

  • Areas such as Lake Nakuru in Kenya are quite specalised as millions of flamingos flock and live in these harsh environments to gain nutrients when feeding on spirulia.

  • This is clearly an advantage to these birds as they are adapted to unique conditions which enable reduced competition from other species.

  • Flamingos are originally white when born, however by ingesting carotenoids pigments (from halophiles) they slowely turn pink in colour. 

The Great Salt Lake

 

  • The Great Salt Lake is suitated in the state of Utah, USA.

  • The salinity of this lake is  3.5 - 8 times saltier than the ocean.

  • At an elevation of 4,200 feet UV levels are about 15% higher.

  • The average depth of this lake is 14 feet, with a maximum depth of 33 feet.

  • The water tempreature can range between below freezing in the winter and 80 degrees Farrenheit in the summer. 

  • Levels of salinity are normally high when precipitation is low as small amounts of water is introduced. 

  • It is known for being the forth largest and the second saltiest lake in the world.

  • Within this lake, adult brine shrimps are situated. They have a high salt tolence of 30%, therefore when the salinity levels of the lake is low the amount of shrimps decrease. As a result, organisms such as protozoa increase in numbers.

  • When salinity level is high the Adult Brine Shimp will be smaller in size and mature quickly at an earlier stage. 

What are the Two Distinct Groups when Determaining the Ecology of Halophiles? 

 

  • 1 - Thalassohaline environment -  Found in cold conditions, such as, the Deep Lake in Antarctica where the surface can reach as low as -20 degrees Celsius (DasSarma, 2006). There is evidence that halophiles can exists in these treacherous settings. The Great Salt Lake is another example.

  • 2 - Athalassohaline environment - Found in environments such as the Dead Sea, which was previously discussed. It contains a high concentraion of cations such as Calcium and Magnesium. The pH level is 6 and acidic in nature. 

  • Another feature of this type of environment is Alkaline Soda Lakes, these have low amounts of cations and are actually rich in carbonates. This allows high alkaline pH levels above pH 9 to exist. Both halophiles and alkaliphiles can exsist in this niche which is suprisingly unique.

 

Properties of Salt

  • The propeties of salt should be understood when researching about Halophiles.

  • Salts are ionic compounds and are formed by replacing one or more hydrogen ions of acid with alternative positive ions.

  • Halophiles benefit and work alongside salt, these ions encourage many mechanisims within this cell.

References

 

  • DasSarma, Shiladitya. Encyclopedia of Life Sciences. London: Nature Pub. Group, 2002. Halophiles. University of Maryland, 12 Mar. 2012. Web. 25 Nov. 2014.

  • "Physical Characteristics of Great Salt Lake." Physical Characteristics of Great Salt Lake. University of Utah, 2014. Web. 25 Nov. 2014.

  • "Lowest Elevation | Dead Sea." Lowest Elevation | Dead Sea. Extreme Science, 2013. Web. 24 Nov. 2014.

  • Baxter, B., et al. “Microbial Diversity of Great Salt Lake.” Cellular Origin, Life in Extreme Habitats and Astrobiology. 2005: 9. Adaptation to Life at High Salt Concentrations in Archaea, Bacteria, and Eukarya. Netherlands: Springer Netherlands, 2006.

  • Stephens, D. and Gardner, J. “Great Salt Lake, Utah.” USGS Water-Resources Investigations Report 99-4189. Apr. 2007.

  • Wurtsbaugh, W. “Food-web modification by an invertebrate predator in the Great Salt Lake (USA).” Oecologia 89.2 (1992): 168-175.

  • Corixid. 2008. Encyclopedia Britannica Online. 21 August 2008. < http://www.britannica.com/EBchecked/topic/636982/water-boatman>.

  • Oren, Aharon Dr. "Ecology of Halophiles - Springer." Ecology of Halophiles - Springer. Springer, 2014. Web. 25 Nov. 2014.

  • Wiegel Et Al, Juergen. "HALOPHILIC THERMOPHILES: A NOVEL GROUP OF EXTREMOPHILES." HALOPHILIC THERMOPHILES: A NOVEL GROUP OF EXTREMOPHILES (n.d.): 1-38. Web. 25 Nov. 2014. <file:///C:/Users/Jasbir/Downloads/Halophilic%20Thermophiles%20(Noha).pdf>

  • Oren A. “The dying Dead Sea: The microbiology of an increasingly extreme environment.” Lakes & Reservoirs: Research and Management, 2010, DOI: 10.1111/j.1440-1770.2010.00435.x

  • Oroud IM. “Evaporation estimates from the Dead Sea and their implication on its water balance.” Theor Appl Climatol, 2011, DOI: 10.1007/s00704-011-0452-6

  • S. Atanasova, Nina. "PROKARYOTIC MICROORGANISMS, VIRUSES, AND ANTIMICROBIAL AGENTS FROM HYPERSALINE ENVIRONMENTS."Https://helda.helsinki.fi/bitstream/handle/10138/38663/Thesis_Atanasova.pdf?sequence=1http://www.space.com/1332-seeking-deep-space-salt-lovers.htmlhttp://books.google.co.uk/books?12) id=Q5icH0OdnX8C&pg=PA548&lpg=PA548&dq=The+BioPan+halophile+experiment.&source=bl&ots=P1Sx0iWmPf&sig=Uo-hlQrGEBUgGtqAH19Z-xQ-. University of Helsinki, 2013. Web. 25 Nov. 2014.

  • Rothschild Et Al, Lynn. "The BioPan Halophile Experiment." Nature.com. Nature Publishing Group, 22 Feb. 2001. Web. 25 Nov. 2014.

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