Structure, growth, and decomposition of laminated algal-bacterial mats in alkaline hot springs
Laminated mats of unique character in siliceous alkaline hot springs of Yellowstone Park are formed predominantly by two organisms, a unicellular blue-green alga, Synechococcus lividus, and a filamentous, gliding, photosynthetic bacterium, Chloroflexus aurantiacus. The mats can be divided approximately into two major zones: an upper, aerobic zone in which sufficient light penetrates for net photosynthesis, and a lower, anaerobic zone, where photosynthesis does not occur and decomposition is the dominant process. Growth of the mat was followed by marking the mat surface with silicon carbide particles. The motile Chloroflexus migrates vertically at night, due to positive aerotaxis, responding to reduced O/sub 2/ levels induced by dark respiration. The growth rates of mats were estimated at about 50 ..mu..m/day. Observations of a single mat at Octopus Spring showed that despite the rapid growth rate, the thickness of the mat remained essentially constant, and silicon carbide layers placed on the surface gradually moved to the bottom of the mat, showing that decomposition was taking place. There was a rapid initial rate of decomposition, with an apparent half-time of about 1 month, followed by a slower period of decomposition with a half-time of about 12 months. Within a year, complete decomposition of a mat of about 2-cm thickness can occur. Also, the region in which decomposition occurs is strictly anaerobic, showing that complete decomposition of organic matter from these organisms can occur in the absence of O/sub 2/.
- Research Organization:
- Wabash Coll., Crawfordsville, IN
- OSTI ID:
- 5206182
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Vol. 34:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
BACTERIA
BIODEGRADATION
UNICELLULAR ALGAE
AEROBIC CONDITIONS
ANAEROBIC CONDITIONS
HOT SPRINGS
OXYGEN
PH VALUE
PHOTOSYNTHESIS
PLANT GROWTH
YELLOWSTONE NATIONAL PARK
ALGAE
BIOMASS
CHEMICAL REACTIONS
CRYOGENIC FLUIDS
DECOMPOSITION
ELEMENTS
ENERGY SOURCES
FLUIDS
GROWTH
MICROORGANISMS
NONMETALS
PHOTOCHEMICAL REACTIONS
PLANTS
PUBLIC LANDS
RENEWABLE ENERGY SOURCES
SYNTHESIS
THERMAL SPRINGS
550700* - Microbiology