There are still some mysteries left in the world—even if, as Sam Schmitz has learned, you sometimes have to dive pretty deep to find them.

One place abounding with mystery is Africa’s Lake Tanganyika. Divided among four countries, it is the world’s second-largest, second-deepest freshwater lake. Its depth (4,820 feet) and relative calmness discourage water layers from mixing, and oxygen is scarce. But life perseveres, even thrives, in these conditions.

Schmitz, a senior majoring in microbiology and French (with an honors in research), has had the oppor- tunity to study this remarkable body of water without actually going there. As the recipient of an Undergraduate Research Fellowship Program grant from the American Society of Microbiology, Schmitz is analyzing water samples collected at Lake Tanganyika by UW–Madison limnologist Peter McIntyre and his team.

Using DNA sequencing, Schmitz has found that the deepest depths of the lake are home to incredibly diverse microbial communities. He and his fellow researchers have already identified numerous unclassified bacteria.

“The microbiome of the lake has not yet been thoroughly studied, so the lake may hold many more unique, undiscovered bacteria,” says Schmitz—a revelation that amazes him, given how much is known about other ecosystems. These same microbes, he says, may drive the processes that sustain life in the lake’s depths.

As his research project, Schmitz hopes to build on existing knowledge of the dynamics between microbial communities and their ecosystems. “I have always been interested in microbial communities and their interactions with the environment,” Schmitz says.

Such research comes at a time when the lake’s fragile ecosystems are most vulnerable, Schmitz notes. Climate change threatens to disrupt a natural order eons in the making. Better understanding the role of microbes in the cycling of lake nutrients could help us understand how Lake Tanganyika currently supports such abundant life, Schmitz says.

As a fresh graduate this summer, Schmitz plans to work in industry for a few years before returning to school—and his passion for research—to pursue a Ph.D.