Microbial Life > Research Methods > Bio-geochemical Methods > Mammoth Terraced Architecture > Results

Results:Mammoth Hot Springs

Created by George Rice, Montana State University

Images of terraces at Mammoth being studied.
Members of the Fouke lab sampling at the terraces, and the essence of Mammoth Hot Springs during the winter months. Images provided by the Fouke lab.

  1. A generic approach to large scale modeling of terraced architecture at Mammoth Hot Springs has been used to explain the formation of ponds, the variations in terrace morphology, the apparent scale-invariance of the landscape and even the quantitative properties of simple landscape motifs. This approach is based on principles of fluid dynamics, precipitation kinetics and crystal growth dynamics rather than one that hinges on specific material parameters or system components such as microbes. (Goldenfeld, Chan, Veysey; submitted to Physical Review Letters, 2006).
  2. On the micron to centimeter scale, however, the presence of bacteria have been shown to influence the form, distribution and chemistry of the carbonates precipitated at Mammoth Hot Springs. More importantly, we have demonstrated that microbes present in the system at Mammoth Hot Springs positively influence crystal growth rates and, further, that specific isotopic fractionation of carbon occurs as a result of this increase.
  3. Utilizing culture-independent molecular techniques at Mammoth Hot Springs, a survey of the bacteria indicates that the bacterial communities are partitioned between depositional facies in the surface drainage system. Sequences exhibited <12% similarity in bacterial community composition between each of the travertine depositional facies (defined in Fouke et al, 2000. JSR Vol.70, No.3, 565-585).
  4. Bacterial metabolic signatures provide a means of evaluating functional metabolism as measured by ?13C in phospholipids and glycolipid fatty acid fractions of bacteria from Mammoth Hot Springs. This is because different biosynthetic pathways result in distinct isotope fractionation patterns. These results demonstrate the potential for using lipid biomarkers and isotopic fractionation to understand the CO2 fixation pathways that may exist within complex spring systems.

Copyright on all images and material by Bruce Fouke, 2006.

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