A long-range Autonomous Underwater Vehicle (AUV) for oceanographic research. A suite of miniaturized physical and bio-optical instruments, which measure in situ water properties including ... temperature, salinity, and the absorption and scattering of light in the water column, have been and are currently under development for placement in the glider's science payload bay. Seagliders fly through the water with extremely modest energy requirements using changes in buoyancy for thrust coupled with a stable, low-drag, hydrodynamic shape. Designed to operate at depths up to 1000 meters, the hull compresses as it sinks, matching the compressibility of seawater.
For further description see http://www.apl.washington.edu/projects/seaglider/summary.html.