|WHAT ARE ALGAE?
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,
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.
WHAT ALGAE LIVE IN THE GREAT SALT LAKE?
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 viridis. D. 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
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 http://www.nr.state.ut.us/dwr/brine\bsjun98.htm for a recent
ARE THE OPTIMUM TEMPERATURES AND HABITAT?
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.
WHAT ROLE DOES ALGAE PLAY IN THE CYCLES OF THE GREAT SALT LAKE?
|Oxygen is generated by photosynthetic
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
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
Gwynn, J. Wallace.
Great Salt Lake: a Scientific, Historical and Economic Overview.
Utah Geological and Mineral Survey; a division of the Utah Department of Natural Resources Bulletin 116,
Sorensen, Ella, and George,
John P. Seductive Beauty of Great Salt Lake: Images of a
Gibbs Smith Publisher, 1997.
Stephens, Doyle. Salinity-Induced
Changes in the Aquatic Ecosystem of Great Salt Lake, Utah. pp.
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. http://www.nr.state.ut.us/dwr/bsupdt.htm