Great Salt Lake Bacteria

 
      The Great Salt Lake is artificially divided into two parts by a railroad causeway; the North

Arm and the South Arm, due to the stop of free circulation the North Arm routinely has higher

salinity. Bacteria are very important to the health of both arms of the lake. Bacteria are the

simplest and most primitive of all life. They are prokaryotic unicellular organisms. That means

that they consist of one cell that has no defined nucleus and are in the Biological Kingdom

called Monera.

 
WHY ARE BACTERIA IMPORTANT?

      Bacteria digest organic matter, such as dead brine shrimp,brine flies, and algae. In doing so

they recycle nutrients such as nitrogen and phosphorus and return it to the food web. They also

digest the  uric acid, an organic form of nitrogen excreted by the Brine Shrimp and Brine Flies,

thereby releasing Ammonia (NH3) , Biocarbonate (HCO3), and Carbonite ion (CO3). These

compounds, especially ammonia, are used by the algae. Bacteria are also a major food source

for developing young Brine Shrimp and Brine Flies.

 

The Great Salt Lake Food Web
 
 

WHAT IS THE BIOLOGY OF THE SOUTH ARM?

    The South Arm has a lower salinity and therefore has more types of Bacteria. As many as 15

distinct types of bacteria have been found, but further studies are necessary. The types

commonly found are:
 

Micrococcus subflavus                   non motile sphere
Bacillus cohaerens                          motile rod, single or in pairs
Bacillus freudenreichii                    motile rod, single or in chains
Bacillus mycoides                            rods in chains with spores
Achromobacter solitarium              slender motile rods
Achromobacter album                     non motile rods
Achromobacter hartlebii                  motile single rods
Flavobacterium arborescens           non motile rods, pairs or chains
Bacterioides rigidus                         motile slender rods, single or in pairs
Serratia salinaria                               single motile rods, non motile in GSL
Cellulomus subcreta                        single motile rods, non motile in GSL
                ( Fredrick, 1924 in Gwynn, 1980)
 

WHAT IS THE BIOLOGY OF THE NORTH ARM?

    Due to the high salinity the North Arm has far fewer types of bacteria. In fact only two types

have been found, the Halobacterium and Halococcus.

Halobacterium

        Some of these halobacteria have been found have a rhodopsinprotein in the cell

membrane that is capable of producing ATP in the absence of oxygen and in the presence of

light. (Post, 1977a)  Basically this means that the bacteria is capable of producing energy in the

form of ATP. There are many theory's about the use of this energy and the rhodopsinprotein;

one is that the bacteria needs the energy for extreme salt regulation, another is that it helps in

DNA repair.

The rhodopsinprotein  is what gives the bacteria its reddish color.  At the end of the growing

season when there is a large concentration of bacteria it  gives the water a reddish tint.
 
 

North Arm October 1998

 
 

        Another interesting phenomenon; generally only found in the North Arm of the lake, is that

Brine Shrimp contain a bacterial symbiont. The current theory is that because the diet of the

Brine Shrimp is so severely limited in the North Arm due to the salinity, the symbiont allows the

shrimp to survive by helping them to obtain the vitamins that they need. That would explain why

the symbionts are not found in the brine shrimp of the South Arm, because the lower salinity

allows a greater variety of organisms in the food web. (Post, and Youssef 1977)

 

Bibliography
 
            Gwynn, J. Wallace, 1980, Great Salt Lake: a Scientific, Historical and Economic Overview.

            Post, F.J., 1977a, Microbiology of the Great Salt Lake north arm, Hydrobiologia 81, 59-69.

            Post, F.J., 1977b, The Microbial Ecology of the Great Salt Lake, Microbial Ecology 3, 143-165.

            Post, F.J. & N.N. Youssef, 1977, A procaryotic intracellular symbiont of the Great Salt Lake brine shrimp Artemia salina (L.), Can J. Microbiol. 23: 1232-1236.
 
 

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