Microbial fuel cells aren't exactly new, but microbial fuel cells scouring the ocean floor? Now that's an initiative we can get behind. The Naval Research Laboratory is currently toying around with a so-called Zero Power Ballast Control off the coast of Thailand, presumably looking for treasures dropped from the speedboat of one "Alan Garner." Purportedly, the newfangled hydrogen fuel cell relies on bacteria to provide variable buoyancy, which allows an autonomous ocean sensor to move up and down water columns with little to no effort. Furthermore, it's able to get its energy from microbial metabolism (yeah, we're talking about hot air), and while it's mostly being used to measure things like temperature and pressure, it could be repurposed for more seirous tasks -- like mine detection. There's no clear word yet on when America's Navy will have access to this stuff, but if we had to guess, they've probably be using it behind our backs for the better part of a score.

[Image courtesy of U.S. Navy Reserve / Tom Boyd]