Over the last three years MBARI engineers have developed a new class of autonomous underwater vehicles (AUVs) to support chemical and biological sensing missions covering ranges of 1,000 kilometers or more. The size and power consumption of desired chemical and biological sensors precluded the use of existing long-range gliders, and the endurance requirement precluded the use of more traditional propeller-driven AUVs. The concept for the new vehicle was a highly energy efficient propeller-driven AUV capable of operating at speeds between 0.5 and 1.0 meters per second. The new vehicle, named Tethys, conducted its first brief autonomous mission in December 2009, just offshore of Moss Landing.
The range and endurance of the new long-range AUV (LRAUV) greatly expands the types of observations and experiments possible with autonomous platforms. For instance, one of the institute’s AUVs carries a comprehensive suite of sensors out to MBARI’s M2 mooring and back. Tethys will carry a smaller, but still impressive suite of sensors 10 times farther, extending the reach of MBARI’s shore-launched AUVs into the California Current system. This will expand researchers' non-ship observational capability beyond the upwelling shadow, well into the oligotrophic (nutrient poor) ocean. This capability also provides a foundation for studying phytoplankton blooms from boom to bust, by providing a mobile platform which can survey a bloom continuously through the two weeks to month-long lifetime of a bloom.