Oregon State University, Ph.D. in Microbiology, 2004
George Mason University, B.A. in Biology and Russian, 1995
Associate Professor, University of Washington, 2013-2015
Assistant Professor, University of Washington, 2007-2013
Postdoctoral Scholar, The University of California, Santa Barbara, 2006-2007
Postdoctoral Research Fellow, Cornell University, 2004-2006
Director of Undergraduate Education, School of Oceanography, University of Washington, 2013-present
Instructor, School of Oceanography, University of Washington, 2007-present
Instructor, Microbial Oceanography, BIOS, 2004-2008
Lecturer, English, Slovak Academy of Sciences, 1997-1999
United States Peace Corps Volunteer, 1997-1999
-English Instructor, Slovak Academy of Sciences, Bratislava, Slovakia
United States Marine Corps, 1987-1992
-Marine Security Guard, American Embassy, Pretoria, South Africa
-Marine Security Guard, American Embassy, Maputo, Mozambique
Marshall, K.T., and Morris, R.M. (2012). Isolation of an aerobic sulfur oxidizer from the
SUP05/Arctic96BD-19 clade. ISME Journal. 7:452–455.
Morris, R.M., Nunn, B.L., Frazar, C., Goodlett, D.R., Ting, Y.S., and Rocap, G. (2010). Comparative metaproteomics reveals ocean-scale shifts in microbial nutrient utilization and energy transduction. ISME Journal 4:673-685.
CULTIVATION OF THE SUP05 CLADE
Shah and Morris: Members of the gamma sulfur oxidizer (GSO) SUP05 clade are among the active and dominant lineages in hypoxic seawater, where they have key roles in the cycling of carbon, nitrogen and sulfur. We isolated four cultured representatives from the SUP05 clade using natural seawater media amended with 1mM thiosulfate. Cells were collected from an anoxic basin in Effingham Inlet, British Columbia and diluted in media prepared from the same location. Four out of 384 cultures were positive for growth and contained SUP05. Effingham Inlet strain GSO-EF1 was selected for further study. Purity was verified by 16S rRNA gene sequence and terminal restriction fragment analyses. GSO-EF1 cultures reached a maximum cell density of 1.2 x 106 cells/ml and had a doubling time of 16 hours under aerobic conditions. These data indicate that SUP05 cells from Effingham inlet are capable of using thiosulfate as an energy source and grow under both aerobic and anaerobic conditions. Further physiological studies will be conducted to elucidate their roles in carbon, nitrogen and sulfur cycling in oxygen minimum zones.
THE COMPLETE GENOME SEQUENCE OF THIOGLOBUS SINGULARIS REVEALS NOVEL EVOLUTIONARY ADAPTATIONS OF CARBON AND SULFUR METABOLISMS IN THE SUP05/ARCTIC96BD-19 CLADE
Marshall, K.T.; Iverson, V.Armbrust, E.V.; Morales, R.L.; Morris, R.M: Gamma sulfur oxidizers (GSOs) are ubiquitous in seawater. Free-living representatives from the Arctic96BD-19 subclade are found in relatively low abundance (<10%) throughout the ocean while free-living representatives from the SUP05 subclade often dominate hypoxic regions. Until recently there were no cultured representatives of the GSO clade and only partial genome sequences were available for comparative genomic analyses with symbionts. The complete genome sequence of Arctic96BD-19 isolate Thioglobus singularis provides evidence that divergence within the GSO clade was driven by evolutionary adaptation of carbon and sulfur metabolisms. Gene synteny and homology suggest that the last common ancestor had both forms 1A and II of RuBisCO. Extant members of the SUP05/Arctic96BD-19 subclade have lost either form 1A or II and retained the other, depending on environmental conditions. Members of the Arctic96BD-19 subclade have lost key sulfur oxidization genes found in SUP05, including sqr used for oxidizing hydrogen sulfide to elemental sulfur and sox used for oxidizing thiosulfate to elemental sulfur. The genome sequence of T. singularis and other GSO isolates will elucidate metabolic differences that drive variation in abundance and distribution.