Bacteria-Water-Rock Interactions Funded by the National Science Foundation and the American Chemical Society, Jeremy B. Fein, associate professor of civil engineering and geological sciences, applies chemical thermodynamics to environmental geomicrobiology as he studies the biochemical interactions of bacteria, rock, and water. “I fill a gap between geology and biology,” says Fein. “We’ve known for a long time that there are bacteria in the ground, even to great depths under the earth’s surface.” According to Fein, both geologists and microbiologists have traditionally ignored the effects of bacteria on contaminant transport in groundwater due to a lack of understanding each other’s discipline. “The exciting part about this work is that it bridges the gap between these two disciplines,” says Fein. “There is a lot of evidence that bacteria interact quite extensively with the minerals in geologic systems. So we’re studying important reactions no one has considered before.” In the last five years environmental geoscientists have developed qualitative evidence that bacteria strongly influence how metals and organic solvents are distributed on the earth’s surface and in groundwater supplies. For example, if lead is dumped at a particular location, it may be bound by the bacteria -- meaning that the lead will come out of the solution and become attached to structures on the cell walls of the bacteria. Bacteria evolved these structures to absorb nutrients like calcium, magnesium, and low levels of zinc and iron. But, bacteria cannot differentiate between those nutrients and metals like lead, copper, cadmium, or uranium. Once the metal attaches to the bacteria, it becomes as mobile as the bacteria. If the bacteria move, they carry the contaminants with them. If not, the pollutants are immobilized. So it is crucial to develop models that determine the extent of attachment and the mobility of the bacteria in groundwater aquifers. Working with researchers from Argonne National Laboratory, and using the Advanced Photon Source synchrotron, Fein and his team are gathering information with which to develop models. “Our goal,” he explains, “is to try to isolate the unique reactions between heavy metals and bacterial surfaces. We use a specific bacteria species and place it in contact with a specific groundwater contaminant to determine how they interact.” There are countless species of bacteria in soil and groundwater systems. Fortunately, the geomicrobiology team doesn’t have to study each species of bacteria. Instead they are looking for common threads. “One of the most exciting things we’ve found,” says Fein, “is that all the bacteria we have tested behave in the same way. There’s a common structure to the bacterial cell wall that makes predicting bacteria-metal interactions much easier.” It’s important to note that these experiments are the first to quantify the effect of bacteria on aqueous metal, organic adsorption, and mineral dissolution. In addition, the results can be used to make groundwater clean-up efforts more efficient and to design more effective contaminant treatment strategies. Fein works with two graduate students and approximately four undergraduates each year. He believes the size of the College of Engineering is a benefit for graduate students, but perhaps more so for undergraduates. “The undergraduates who work in the Environmental Geochemistry and Geomicrobiology Laboratory participate in independent research, in much the same manner as do the graduate students,” explains Fein. “It is one of the tangible advantages of being at a top research university as an undergraduate.” In fact, as a result of their lab activities, most of the undergraduates under Fein’s supervision have been listed as authors in research publications. Highlighting Undergraduate Research Traditionally an undergraduate’s opportunities for hands-on research are quite limited. That’s not the case in the College of Engineering, especially in the Department of Civil Engineering and Geological Sciences. In addition to faculty, visiting scholars, and graduate students, a total of 21 undergraduates work in the department’s research labs. Jonathan Roller, a senior majoring in environmental geosciences, is one of them. In fact, he’s worked in two different labs over the last three semesters. During his junior year, Roller worked with Clive R. Neal, associate professor of civil engineering and geological sciences and director of Notre Dame’s Inductively Coupled Plasma-mass Spectrometry Facility. Roller’s main responsibility was to prepare samples for testing. This year he’s working with Jeremy B. Fein, associate professor of civil engineering and geological sciences, and Peter Wightman, a doctoral candidate, in the Environmental Geochemistry and Geomicrobiology Laboratory. Roller spends approximately three hours every day in the lab. “We’re testing a specific bacteria -- Bacillus subtilis -- varying the range of pH and the amount of electrolyte in the solution, then adding a concentration of heavy metal to determine how the pH and electrolyte concentrations affect the level of metal adsorbed onto the surface of the bacteria,” said Roller. “It’s a very strict regimen. You have to be in the lab exactly 24 hours after you initially feed the bacteria or the results could be skewed.” Roller has enjoyed the experience so much it’s encouraged him to apply to graduate school. The biggest benefit to working in the labs, he says, is two-fold. “You see the data firsthand so it becomes more than something in a textbook. And, I think it gives students an excellent idea of what graduate school is about. My experience here as an undergraduate is the main reason I will be pursuing a graduate degree.”