Autonomous Underwater Vehicle

Background

Natural Iron Enrichment
Occurring to a measurable extent in coastal upwelling zones, certain processes control the transformation of resuspended iron into bioavailable iron.  The "natural iron enrichment experiment" looked at the entrainment in upwelled water of iron-rich sediment from the continental shelf.  This iron is important to phytoplankton growth, but only two previous experiments have tracked it.  Using a single ship to track a patch of water in a Lagrangian reference frame while concurrently mapping filament boundaries in an absolute reference frame led investigators to use AUVs to map off-shore frontal boundaries using primary physical measurements.  Several AUV surveys were sent along drifter tracks, thus along frontal boundaries.

Frontal Processes
Off the California coast, frontal instabilities develop along the cyclonic boundary of upwelling filaments, and strong local upwelling occurs in association with these instabilities.  The dynamics of this upwelling are not understood and the biological effects of the upwelling have not been examined.  Strong local upwelling significantly impacts cycling of nutrients and particles within the evolving filament.  AUVs were used to investigate the spatial structure of upwelling and down-welling along filament fronts in Monterey Bay, to define the dynamical basis for the vertical motions, to quantitatively assess the flux of water and chemicals along these boundaries, and to define relationships between biological distributions and physical processes associated with these instabilities. 

Iron from Seafloor Venting
Remote sensing studies of the San Gregorio Fault Zone have identified this area as being associated with gas and perhaps fluid discharging that is adequate to produce acoustically detectable water-column plumes.  AUV surveys were used to help establish whether these acoustical plumes are, in fact, associated with seafloor venting. 

The Dorado / MBARI autonomous underwater vehicle (AUV) program is an engineering lead program combining several elements from the various groups here at MBARI and
collaborations with external research institutions.  The AUVs used in MUSE hosted a number of instruments, including a prototype methane sensor on the daytime vehicle and a bioluminescence sensor on the nighttime vehicle.

Data Index Aircraft AUV CODAR
Drifters Moorings Satellites Ships