My primary research interest is the development of benthic microbial fuel cells. I work in Clare Reimers' lab group at Oregon State University's Hatfield Marine Science Center. Fuel cells are devices that convert chemical energy to electrical energy. This is also what a battery does but there are a couple of key differences: 1) in a fuel cell the chemical reactants are externally supplied rather than preloaded into a battery and 2) the electrodes in fuel cells are catalytic surfaces for the reactive substances, but they aren't consumed like electrodes in a battery.
In our fuel cells, we take advantage of microbially mediated redox reactions that naturally occur in the sediment column. These reactions create a reduced environment a few centimeters below the sediment water interface. We insert an electrode into this environment to oxidize those reduced chemicals using another electorde in the oxygenated bottom water to complete the circuit. When the circuit connected through a resistive load, the electrons naturally flow and produce current. My project is to design a fuel cell that overcomes the limitation of mass transport to the anode.
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Prviously I worked on a project to measure in situ microbial activity in the deep subsurface. Part of my work was done at the Deep Biosphere Lab at Goteborg University in Sweden. Karsten Pedersen, the director of the lab, wrote a great introduction to the deep biosphere which is better than I could have written. Click here to visit the lab's webpage and read the whole story.
“It is more than 135 years ago now. Two geologists and a local guide climbed into the extinct volcano Sneffel on Iceland. In the electric light from their “ruhmkorff devices” they continue their decent into the earth – further and further down. The fantastic adventure of Professor Lidenbrock and his nephew Axel can be read in Jules Verne’s famous book, Journey to the centre of the Earth. Deep under the surface of our planet, the three friends find an entire ocean with many mysterious life forms. While this story was indeed fantasy, the author correctly predicted the fluorescent tube. Not only did he correctly predict the invention of a light source; in a sense he was also correct in predicting life to be abundant deep under ground, albeit in cavities much smaller than imagined in his book. Life is surprisingly abundant underground. Today, research directed towards exploring intra-terrestrial microbial life is a rapidly growing field reflected by an increasing number of articles, meetings and workshops regarding the secrets of deep intra-terrestrial microbes. “
“The number of intra-terrestrial microbes varies notably depending on the underground site studied. Values in the range of one thousand up to one hundred million microbes per ml groundwater or gram sediment are commonly reported. Although the dry weight of hundred million microbes in one gram of sediment is very small, in the range of 1 - 10 micro-gram, the total weight of microorganisms in many square kilometres of seafloor and continental shelve sediments, rock aquifers etc. may reach an impressive number. An attempt to estimate the total carbon in terrestrial and intra-terrestrial environments was made recently. These calculations indicate that the total amount of carbon in the intra-terrestrial organisms may equal that of all terrestrial and marine plants. Although subject to a great deal of uncertainty, the estimates suggest that the biomass of intra-terrestrial life is very large. A wealth of microbial life may exist deep inside Earth with many new species, representing novel microorganisms with unique physiological and biochemical features that await exploration. “
In 2004 I participated as a shipboard scientist on Expedition 301 of the Integrated Ocean Drilling Program. It was the innaugural expedition of IODP. It was on this 2-month trip that I began to call myself an oceanographer. When we got on the ship, the Portland Oregonian sent a reporter and they interviewed me for a little “local flavor”. Click this for text of the article.
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