February 23, 2007

Stocker Chosen for Doherty Professorship

Roman Stocker, assistant professor in the Department of Civil and Environmental Engineering, has been awarded the 2007 Doherty Professorship in Ocean Utilization [ http://web.mit.edu/seagrant/doherty/ ] from the MIT Sea Grant College Program. Every year, the program selects one or two new faculty members for a supplemental award of $25,000 per year for two years.

Endowed by the Henry L. and Grace Doherty Charitable Foundation, the Doherty Fellowship encourages promising, non-tenured professors to undertake marine-related research that will further innovative uses of the ocean's resources. The area of research may address any aspect of marine use and/or management, whether social, political, environmental, or technological.

Stocker's research will focus on improving our understanding of marine microorganisms, which are at the base of the oceans' food web and are essential to the oceans' healthy functioning. "We're interested in how swimming microorganisms actively respond to their environment," says Stocker, "as that strongly influences how nutrients are recycled in the ocean, and ultimately made available to other organisms."

To date, quantifying these microscale interactions has been extremely difficult because they occur on too small a scale to be studied in the field, and recreating their environmental conditions in the lab has previously not been possible. To effectively study fluid mechanics at these small scales, Stocker uses custom-tailored microchannel devices. Tiny channels, with typical sizes of hundreds of microns, are sandwiched between a polymer on the top and a glass microscope slide fused to the bottom. Syringes and pumps generate flows of varying speeds in the channels, and nutrient and flow scenarios mimicking those in the ocean can be created.

"My work in microfluidics gives the biologists the ability to look at microorganisms in their environment in a manner that's impossible in the ocean, where the organisms are too small and the conditions too changeable. In the lab we can very carefully recreate typical conditions of a microbe's environment, and we can accurately track where the creatures go by attaching a video camera to the microscope," explains Stocker.

In his Doherty-funded research, Stocker will look at whether bacteria can find patches of high nutrient concentrations and get to them before they dissipate by diffusion or flow. If the bacteria reach the patch, they can gobble up nutrients such as carbon and nitrogen: these elements were initially thought to be lost from the food web. But "if bacteria can rapidly find and consume nutrients, they will be recycling them and ultimately they will be returned to the food web. These processes can totally change our estimate of the carbon cycle in the ocean," explains the researcher.

Stocker expects this study to help answer important questions such as how marine microbes find food, avoid predation, and survive in a turbulent and heterogeneous world. The answers he finds will contribute to a more thorough understanding of the oceans, and may aid in fisheries and aquaculture endeavors, as well as water quality monitoring, and our understanding of the role the oceans play in climate change. (This article includes excerpts from an article by Debbie Levey in the Civil and environmental Engineering at MIT newsletter.)