People: Astrobiology Faculty

Jody Deming
Oceanography

My research interests concern the limits of microbial life on Earth and enzyme-based strategies that allow microbes to push the limits as we perceive them. My formative research years were with NASA at the Goddard Space Flight Center, where I worked with "leftover" Viking mission technology to develop enzyme-based microbial detection assays. Graduate-level research (at the University of Maryland in College Park, PhD in 1981) then led me to examine effects of the hydrostatic pressures that characterize the cold deep ocean on microbial metabolism and growth. That work included isolation of novel pressure-requiring bacteria for which we eventually established a new genus, Colwellia, named after my advisor, Rita Colwell. Today, my students work with Colwellia psychrerythraea strain 34H, whose whole genome has been sequenced, as our model cold-adapted bacterium. My postdoctoral and independent research in the 1980s considered the combined effects of elevated pressure and temperature, as a result of the then-recent discovery of hydrothermal vents and thermophilic organisms from them.

An opportunistic trip to the Arctic Ocean in 1987 captured my imagination with regards to near-freezing seawater and the ice that forms from it, and launched a still-continuing focus on field research in the high Arctic. Although laboratory and modeling work, often addressing microbial enzymes and exopolymers, is certainly part of my group's research, I embrace the philosophy that examining microbial behavior in situ, with as little disruption to the natural habitat as possible and as much knowledge of the physical- chemical environment as possible, can change the way we think about the limits of microbial life and the ability to survive extreme conditions. Interdisciplinary collaboration has become a hallmark of much of the work from my group, thanks in large part to ice- geophysicist Hajo Eicken at the University of Alaska, Fairbanks, and to many Canadian and other international Arctic colleagues.

Evidence for an ocean under the ice cover of Europa today (and an ocean on Mars in the past) brought me into the UW Astrobiology Program and has caused me to focus almost all of my efforts on microbial life in the cold, especially in saline ice formations. Within Arctic winter sea ice, briny fluids remain liquid down to at least -35°C, providing a whole new perspective on the limits to microbial life found within those brines. Because the accessible surfaces of Mars and Europa are on average at very cold temperatures (-55°C and much below), I am challenged to understand Earth life under such deeply frozen conditions. At UW, we have an Extremophile Laboratory (in the School of Oceanography, run jointly with John Baross and thanks to an NSF-IGERT award) that allows for inventive experimentation under both Earthly and extraterrestrial extremes and temperature and pressure.

Departmental Home Page

Publications

Deming, J.W., and H. Eicken. 2007. Life in ice. In Planets and Life: The Emerging Science of Astrobiology, W.T. Sullivan IV and J.A. Baross, eds., Cambridge University Press, pp. 292–312.

Wells, L.E., and J.W. Deming. 2006. Modeled and measured dynamics of viruses in Arctic winter sea-ice brines. Environ. Microbiol. 8(6):1115–1121.

Junge, K., H. Eicken, B.D. Swanson, and J.W. Deming. 2006. Bacterial incorporation of leucine into protein down to –20°C with evidence for potential activity in subeutectic saline ice formations. Cryobiology 52:417–429.

Methé, B.A., K.E. Nelson, J.W. Deming, and 24 others. 2005. The psychrophilic lifestyle as revealed by the genome sequence of Colwellia psychrerythraea 34H through genomic and proteomic analyses. Proc Nat Acad Sci USA 102(31):10913-10918.

Junge, K., H. Eicken, and J.W. Deming. 2004. Bacterial activity at –2 to –20°C in Arctic wintertime sea ice. Appl. Environ. Microbiol. 70:550-557.