Stroud Scientists at Work Under the Microscope: Introducing Jinjun Kan, Microbial Ecologist
650,000 years ago the pressure release from a magma chamber beneath a supervolcano created a massive explosion that formed a physical depression known today as the Yellowstone Caldera in Yellowstone National Park, WY. The stunningly beautiful, freshwater lake that sits on this caldera is home to some interesting microbes and the subject of exciting research by Jinjun Kan, the Microbial Ecologist who will join the Stroud Water Research Center in the spring.
YELLOWSTONE LAKE: A HOTBED OF RESEARCH With the help of remotely operated vehicles (ROV) equipped with special cameras, Kan and fellow scientists from Montana State University are collecting water samples from the lake surface and floor, where hydrothermal vents regularly produce hot water with temperatures of 60-100 degrees Celsius (140-212 degrees
Fahrenheit).
In this seemingly inhospitable environment, unique single cell microorganisms, including bacteria and archaea, thrive, despite explosions of hot fluid and the other unusual geological and geochemical features of the lake. Kan wants to know why.
“Using molecular techniques, we’re enhancing our understanding of microbial distribution patterns and how the microbes interact with their ambient environments,” says Kan. “What we learn will shed light on the genetic diversity, as well as the various functions of the biological community that are linked to the geochemical signatures of its environment, allowing us to explore new, potential functions for these microorganisms.”
MICROBIAL FUEL CELLS: A GREEN SOURCE OF POWER?
To contrast this research with another project Kan is currently working on is an exercise that provides great insight into both the breadth of his interests and the depth of his skill set. Let’s fast forward to the future and the concept of Microbial Fuel Cells; that’s right, fuel cells that could be used to generate power. “While it may be a bit premature to talk about finding a green fuel source for lighting,” says Kan, “I’m very optimistic about the potential of this research.”
This is not science fiction. A lot of bacteria, including members of the genera Shewanella and Geobacter, are able to transport electrons to a solid metal surface. By using pure culture species, it has been demonstrated that bacterial cells generate power under anaerobic conditions provided with appropriate carbon sources (electron donors). Kan’s research has shown that bacterial communities enriched from different resources, such as sewage, freshwater and marine sediments, can provide higher power generation and better stability than pure culture bacteria, as well as the ability to use diverse carbon sources as food. Kan is studying the bacterial consortia enriched in fuel cells to understand and optimize the community composition required for reliable power production, something that has many potential applications.
Says Kan of this ‘enriched’ bacterial community, “We hypothesize that these bacteria will have the ability to work as a team, creating a self-sustaining ecosystem of sorts. If we’re successful, we could eliminate the need for power supplies in certain devices and the power generated by these organisms would be sufficient to operate such things as remote sensors.” That idea excites him tremendously, as the distant placement of these devices makes them extremely difficult to maintain. Monitoring and replacing failed batteries when a device is planted deep under water, for example, can be a challenge. This new, green fuel source could potentially enable him and his colleagues to build more reliable scientific tools to monitor environmental data in remote areas, something that Kan believes will happen soon.
GETTING RID OF HEAVY METAL
When Kan talks about heavy metal, he’s not referencing his taste in music. He’s sharing his excitement about the potential to induce and enrich a bacterial community to help remove the toxic byproducts of industrial activities — such as copper, lead and zinc — that are deposited in marine sediments.
Working with the scientists at the Space and Naval Warfare Systems Command (SPAWAR System Center, Pacific), a Navy research branch in San Diego, CA, Kan is evaluating the impact of alterations to sediment on water quality and ecotoxicity. In other words, Kan’s research will determine how these changes affect the ecosystem — from the structure of the microbial community to the ambient environment in which they live.
Organic additions like acetate and chitin, for example, stimulate microbial growth and reshape the species composition of the microbial community. Kan’s work has shown that by adding heavy metals to sediment instead, important bacterial groups — including sulfate-reducing bacteria (SRB) and sulfide-producing/metal-reducing bacteria — are transformed, stabilizing the heavy metals, and enabling their sequestration in marine sediments.
NO STRANGER TO THE CHESAPEAKE A native of Shandong, China, and current resident of Los Angeles, CA, Kan is no stranger to the largest estuary in the U.S., the Chesapeake Bay. He conducted his doctoral research in Environmental Microbiology at the University of Maryland, College Park, where his research focused on determining the kinds of bacteria that live in the Bay, as well as their distributions, population dynamics, and functions within the estuarine ecosystem. He’s excited to return to the area.
Says Tom Bott, the senior research scientist and head of the Microbial Ecology group whose retirement in 2009 catalyzed the search for a candidate with Kan’s qualifications, “The field of microbial ecology has been revolutionized over the past two decades by the application of molecular techniques to identify microorganisms in complex natural communities, even when we cannot culture those organisms in the lab. Jinjun has expertise in this area and his research here will deepen our understanding of microbial functions in streams because he’ll be able to link a particular function with the organisms that are actually doing the work. This is exciting in and of itself, but it could also open up innovative ways to leverage the capabilities of these microbes in solving environmental problems.
“There’s nothing like seeing microorganisms functioning at the extremes of life in a place such as Yellowstone,” Bott adds. “Both Jinjun and I did our post-doctoral work there before joining Stroud Water Research Center.” With a wry smile he adds, “I’ll say nothing more about the 40-year gap in the years we worked there!”
Bott will work with Kan on a transitional basis throughout 2010.
650,000 years ago the pressure release from a magma chamber beneath a supervolcano created a massive explosion that formed a physical depression known today as the Yellowstone Caldera in Yellowstone National Park, WY. The stunningly beautiful, freshwater lake that sits on this caldera is home to some interesting microbes and the subject of exciting research by Jinjun Kan, the Microbial Ecologist who will join the Stroud Water Research Center in the spring.
A native of Shandong, China, and current resident of Los Angeles, CA, Kan is no stranger to the largest estuary in the U.S., the Chesapeake Bay. He conducted his doctoral research in Environmental Microbiology at the 
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