Patricia L. Siering
Microbial Physiology and Ecology
Phone: (707) 826-3120
Office: Science B 220
Personal Website: http://users.humboldt.edu/plsiering
BS (1985) University of California, Berkeley
MA (1990) San Francisco State University
PhD (1996) Cornell University
Principles of Biology
Life at the Extremes
Summary of research
My research combines molecular and traditional culture-based approaches to investigate microorganisms in natural habitats.
My efforts are broadly directed toward the following investigations: (1) the role of bacteria in biogeochemical cycling in
natural habitats - specifically related to nitrogen and sulfur cycling in high temperature / acidic environments, iron and
manganese transformations in neutral pH environments, and nitrogen cycling in aquatic and terrestrial systems. (2) the diversity,
physiology and genetic processes underlying microbial life in high temperature, low pH environments, (3) the assessment and
quantification of microbial biodiversity within natural communities, especially pertaining to the effects of environmental and
anthropogenic perturbations, and (4) the detection of microorganisms, their genes and associated activities in field and
Siering, P. L., J. M. Clarke, and M. S. Wilson. 2006. Geochemical and Biological Diversity of Acidic, Hot Springs in
Lassen Volcanic National Park. Geomicrobiology Journal 23: 129-141.
Hamm, L, J. Kee, A. M. Anacker, M. S. Wilson, and P. L. Siering. 2006. Isolation of Heterotrophic Prokaryotes from a Hot
Acidic Lake (Boiling Springs Lake) in Northern CA. Abstract N-100 in 106th General Meeting of the American Society for
Microbiology, May 21-25 2006, Orlando, FL.
Siering, P. L., and M. S. Wilson. 2004. Geochemical and biological diversity in near boiling acidic hotsprings,
Abstr. N271 in 104th General Meeting of the American Society for Microbiology, May 22-27, New Orleans, LA
Wilson, M. S.,A. T. Carter and P. L. Siering. 2004. Molecular analysis of microbial communities in a 55°C pH 1.7
lake in Lassen Volcanic National Park., Abst. N276 in 104th General Meeting of the American Society for Microbiology,
May 22-27, New Orleans, LA.
Siering, P. L., and M. S. Wilson. 2001. Investigation of environmental and microbial diversity in high temperature, low pH
geothermal features at Lassen Volcanic National Park. Abst. N-197, in 101st Gen. Meet. Am. Soc. Microbiol. May 19-23, 2001.
American Society for Microbiology, Washington, D.C.
Siering, P.L. 1998. The double helix meets the crystal lattice: the power and pitfalls of nucleic acid approaches for
biomineralogical investigations. Am. Mineral. 83: 1593-1607.
Tebo, B.M., W.C. Ghiorse, L.G. van Waasbergen, P.L. Siering, and R. Caspi. 1997. Bacterially-mediated mineral formation:
insights into manganese (II) oxidation from molecular genetic and biochemical studies. In: Geomicrobiology:interactions
between microbes and minerals, J.F. Banfield and K.H. Nealson (eds). Rev. Mineral. 35: 225-260.
Siering, P.L., and W.C. Ghiorse. 1997. PCR detection of a putative manganese oxidation gene (mofA) in environmental
samples and assessment of mofA gene homology among diverse manganese-oxidizing bacteria. Geomicrobiol. J. 14: 109-125.
Siering, P.L., and W.C. Ghiorse. 1997. Development and application of 16S ribosomal RNA-targeted probes for detection of
iron- and manganese-oxidizing sheathed bacteria in environmental samples. Appl. Environ. Microbiol. 63: 644-651.
Siering, P.L., and W.C. Ghiorse. 1996 Phylogeny of the Sphaerotilus-Leptothrix group inferred from morphological comparisons,
genomic fingerprinting, and 16S ribosomal DNA sequence analyses. Int. J. Syst. Bacteriol. 46: 173-182.
Current Grad Students:
Connor Fitzhugh, and Angela McCartney
Former Grad Students:
Francine Arroyo, Carrie Hudson,