Going Deep

The hybrid remotely operated vehicle (HROV) Nereus can be operated as a conventional, tethered underwater vehicle—though the tether is a fiber optic line as thin as a human hair—or as a tetherless autonomous vehicle. In 2009, it reached the deepest deepest spot in the ocean. Later this year, Nereus will permit researchers to return to the Cayman Rise to study the deepest hydrothermal vents on Earth. In 2014, scientists will use Nereus to begin a comprehensive study of the deepest places in the global ocean.(Photo by Chris German, Woods Hole Oceanographic Institution)