Katrina Edwards is a geomicrobiologist who studies the microbiology of hydrothermal sulfides and the igneous ocean crust. She has particular fascination with one common, yet elusive microbial group associated with these deep habitats, the iron oxidizing bacteria. These are the bacteria that make rust. She received her Ph.D. in geomicrobiology from the University of Wisconsin, Madison, in 1999 and spent the following 7 years as a researcher at the Woods Hole Oceanographic Institution, Massachusetts, USA. This is where she “sank to the bottom of the ocean” and never came back up. She is now a Professor of Biology and Earth Sciences at the University of Southern California, Los Angeles, and is the Director of the Center for Dark Energy Biosphere Investigations (C-DEBI; www.darkenergybiosphere.org), an NSF sponsored program created at USC expressly for the study of the deep marine biosphere.