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University of Oregon

Richard Castenholz

  • Emeritus

  • Office: 482 Onyx Bridge
  • Phone: 541-346-4530
  • Lab: 466 Onyx Bridge

Research Interests

The genetic diversity, ecological, and geographic distribution and of isolated strains of the thermo-acidophilic unicellular red algae of the Order Cyanidiales within diverse habitats in Yellowstone National Park, Japan, New Zealand, and Iceland. The small differences in “ecotypes” are now based on sequences of a few genes and physiological characteristics. Multi-locus sequencing will attempt to further differentiate these strains and to correlate ecotypes of this group with specific types of acidic waters and habitats that differ greatly in temperature, pH, and in the content of various metals (e.g. Hg, Fe, Cu, Zn, Al) and metalloids (As).

Selected Publications

Lehr, C.R., Frank, S.D., D’Imperio, S., Kalinin, A.V, Toplin, J.A., Norris T.B., Castenholz, R.W., and McDermott, T.R. (2007). Cyanidial (Cyanidiales) Population Diversity and Dynamics in an Acid-Sulfate Chloride Spring in Yellowstone National Park. J. Phycol. 43: 3-14.

Fleming, E. D., Bebout, B. M., and Castenholz, R.W. (2007) Effects of salinity and light intensity on the resumption of photosynthesis in a rehydrated cyanobacterial mat from Baja California Sur, Mexico. J. Phycol. 43:15-24.

Roeselers, G., Norris, T.B., Castenholz, R.W., Rysgaard, S., Glud, N., Kühl, M. and Muyzer, G. (2007) Diversity of phototrophic bacteria in microbial mats in Arctic hot springs (Greenland). Environ. Microbiol. 9: 26-38.

Fleming, E.D. and Castenholz, R.W. (2007) Effects of periodic desiccation on the synthesis of the UV-screening compound, scytonemin, in cyanobacteria. Environ. Microbiol. 9:1448-1455.

Miller, S.R., Castenholz, R.W. and Pedersen, D. (2007) Phylogeography of the thermophilic cyanobacterium Mastigocladus laminosus. Appl. Environ. Microbiol. 73: 4751-4759.

Fleming E.D. and Castenholz, R.W. (2008) Effects of nitrogen source on the synthesis of the UV-screening compound, scytonemin, in the cyanobacterium Nostoc punctiforme PCC 73102. FEMS Microbiol.Ecol 63: 301-308.

Toplin, J. A., Norris, T.B., Lehr, C.R., McDermott, T.R., and Castenholz, R.W. (2008). The thermo-acidophilic Cyanidiales: biogeographic and phylogenetic diversity in Yellowstone National Park, Japan, and New Zealand. Appl. Environ. Microbiol. 74 (9): 2822-2833.


Bi 475/575  Freshwater Ecology
Bi 431/531  Algae and Photosynthetic Bacteria
Bi 308  Freshwater Biology
Bi 410/510  Life in Extreme Environments