The Great Salt Lake: Algae
    What are Algae?
    What Algae live in the Great Salt Lake?
    What are the Optimum Temperatures and Habitat?
    What Role does Algae play in the Cycles of the Great Salt Lake?
    Algae are small microscopic single cell organisms of  

the Protista and Monera kingdoms.  Some algae protist  

cells have a simple membrane covering rather than a  

rigid cellulose cell wall which makes them soft to eat for  

the brine shrimp.  Several species of algae form the  

phytoplankton which float or swim in the salty water.  

Another type of algae, called diatoms, have cells that  

are  covered with a hard silica cell wall.  In contrast, 

some of the cyanobacteria, or bluegreen algae, of the  

Monera Kingdom have mucous sheaths which coat the  

filaments or chains of cells. They may also secrete  

limestone around them to form the living algal reefs, 

 or "bioherms" found on the bottom of Great Salt Lake.
     Algae are on the bottom of the Great Salt Lake food chain.  It is grazed upon by the brine shrimp swimming in the

water, and the brine fly larvae, living along the lake bottom.  The smaller planktonic algae without cell walls are thought

to be the preferred food for the younger brine shrimp because of its smaller size and texture.


    There are three major types of algae phytoplankton found in the Great Salt Lake: the red pigmented

Dunaliella salina, the green pigmented Dunaliella viridis, and the blue-green algae, or cyanobacteria, Cocochloris.

These species of algae differ from algae found in freshwater lakes because of their tolerance to the high salinity in the

Great Salt Lake.

    Algae constitutes the second largest group in terms of biomass in the Great Salt Lake.  It is well adapted to the

high salinity by the formation of intercellular glycerol.  This keeps the cell free of excessive salt and prevents

destruction due to osmotic pressure by external salt concentration.  The red pigmented Dunaliella salina is largest in

size, about 20 times larger than the green, or Dunaliella viridisD. Salina is also the most prominent, especially in the

North arm, where orange-red patches of water have been reported.  In the past years, the lake has been dominated by 

D. viridis, the small green algae, prominent to the South arm of the lake.  In more recent years, due to a drop in the

salinity levels of the lake, the lake has seen an abundant growth in the larger pennate diatoms, largely replacing the

smaller Dunaliella species.   
According to studies by Doyle Stephens, between 

August 1996 and January 1997, the lake decreased in  

salinity levels from fifteen percent to eleven percent.   

The  pennate  diatoms grow better than the Dunaliellia in  

the  lower salinity levels.  The Dunaliellia flourish at  

moderate  salt levels,  somewhere between 10-15%,  

where as the  diatoms seem to flourish at lower salt  

levels, at less than ten percent.  

    Diatoms are single cell micro organisms characterized by a cell wall made of silica.  It is hypothesized that the

nauplii and early instars of juveniles of brine shrimp produced during the summer are physically unable to ingest

sufficient numbers of the large and tough pennate diatoms.  Numbers of adult shrimp, particularly females, declined

throughout the summer.  This creates a problem where fewer eggs have been found in the female due to nutritional

problems.  See chart.   For more information, link  to\bsjun98.htm for a recent

summer update.

    Algae in plankton can remain mobile in weather even as cold as -5 degrees Celsius.  Most, though, become

dormant.  Optimum temperatures for the algae are 32 degrees Celsius for the D. viridis, and 28 for the D. salina.

Attached, non-planktonic algae can be found growing on surfaces of rocks, wood, tar balls, and sandy beaches.

Some grow as hair like filaments or as small chains of cells.  Some of the filamentous green algae are washed in the

lake from fresh or brackish water sources which surround the lake.     
Oxygen is generated by photosynthetic algae.  It  

becomes trapped under its crust, and waves break  

the domes, releasing the gas as bubbles.  Algae 

are the principle primary producer of organic matter  

in the North arm, which has been found useful to  

the bacteria.  Algae depend on ammonia directly,  

and bacteria produce ammonia from organic matter  

containing nitrogen.  Algae supply organic nutrients  

and stimulate the growth of bacteria to a  

remarkable  degree.  

    From November to March, the algae more or less become dormant.  In March, the water warms and ignites the

activity of the bacteria.  The bacteria utilize and dissolve particulate organic matter left from the previous fall.  This

causes the ammonia levels to increase, causing the first algae bloom of the season.  In early May the brine fly larvae

appear, feeding primarily on the algae, decreasing its volume.  The larvae hatch and the algal bloom goes up again.

In late July, the brine shrimp eat the algae, bringing the amount of algae in the lake down again.  Amounts of bacteria

remain high with peaks of population near peaks of algae and fly growth.  In the fall, the shrimp disappear and one

more small algal bloom occurs and persists depending on temperature.
This is a brief capture of the cycle of the  

ecosystem where each organism plays  

an important role, and where all of the 

organisms feed off of one another, aiding  

in each others's growth.  Algae plays  

an important role in this cycle.  It is a  

prominent link in the food and nutrient  

chain of the Great Salt Lake ecosystems. 



Gwynn, J. Wallace.  Great Salt Lake:  a Scientific, Historical and Economic Overview.  pp.  316-320.
    Utah Geological and Mineral Survey; a division of the Utah Department of Natural Resources Bulletin 116,
    June 1980.

Sorensen, Ella, and George, John P.  Seductive Beauty of Great Salt Lake:  Images of a Lake Unknown.
    Gibbs Smith Publisher, 1997.

Stephens, Doyle.  Salinity-Induced Changes in the Aquatic Ecosystem of Great Salt Lake, Utah.  pp.  1-7 in
    J. Pitman and A Carroll, eds., Modern and Ancient Lake Systems:  New Problems and Perspectives,
    Utah Geological Association Guidebook 26, 1998.

URL:  Brine Shrimp Update.  August 18, 1998.