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#ScienceAtSea

Gallery: The Autonomous Underwater Glider

On March 28, 2015, researchers onboard the NOAA Ship Nancy Foster launched an autonomous underwater glider—commonly called an ocean glider—into the waters off St. Croix. The glider will spend 20 days at sea on a solo mission to collect environmental data. During this mission, the main goal of the glider is to locate places where economically and ecologically important fish such as snappers and groupers are gathering to spawn in time with the lunar cycle. During spawning, some species of fish make grunting sounds. The glider uses an ambient acoustic sensor to "listen" for these vocalizations. Since the NOAA ship can't be everywhere at once, the glider serves as an extra set of "ears" that allows researchers to search for aggregations of fish over a much larger swath of ocean.

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On March 28, NOAA Ship Nancy Foster deployed an autonomous glider off the eastern coast of St. Croix. Diving down to depths of 656 feet, the glider moved westward along the southern edge of the shelf break. On the fifth day, shallow waters slowed progress, and the glider remained off the southwest coast. The glider will continue logging data until its retrieval later this month.

Chief Bosun Greg Walker and Bosun Group Leader James Best work with scientist Tim Battista to prepare the ocean glider for launch.

From left, NOAA Ship Nancy Foster's Chief Bosun Greg Walker and Bosun Group Leader James Best work with scientist Tim Battista to prepare the ocean glider for launch.

Scientist Chris Taylor calibrates a passive acoustic recorder

Scientist Chris Taylor calibrates a passive acoustic recorder called the Remora-ST made by Loggerhead Instruments in Sarasota, Florida. Loggerhead Instruments is a partner with NOAA on this and several projects to better understand bioacoustics (sounds made by marine animals like marine mammals and fishes) for management of fishery ecosystems. The small, self-contained, low power acoustic recorder is attached to the glider and programmed to record underwater sounds for the duration of the 20 day mission around St. Croix. Unlike the oceanographic data also collected by the glider, the recorder will not transmit data back from the glider during the mission. Scientists must recover the glider and recorder to analyze the recordings.

A view from the rear of the glider

A view of the rudder in the rear of the glider. The rudder is used to steer the glider right or left in the water column. A satellite transmitter on top of the rudder is used to locate the glider's position at any time. In this image, the wings of the glider are not yet attached.

the glider just prior to being launched from ship

Scientists and crewmembers prepare to launch the glider—now with wings attached—from the rear of the NOAA ship Nancy Foster. Once released, the pre-programmed glider will operate autonomously.

Once released from the NOAA Ship Nancy Foster, the glider dives under the waves and begins its 20-day solo mission. During its journey, the glider will collect a variety of environmental data. An acoustic sensor mounted on top of the glider is used to search for aggregations of fish; a light sensor on the left of the glider gathers information about sedimentation in the water; and a sensor called a "CTD" gathers information about water salinity, temperature, and depth.