Autonomous robotic submersible collects optical data on ocean environment
Data collection at sea usually requires the deployment of a research ship packed with instruments and scientists. When stormy weather hits, these expensive adventures become nearly impossible to sustain. Furthermore, with this method alone, it is often difficult to gather enough information over space and time to accurately assess trends.
Researchers led by Oscar Schofield from Rutgers University have launched almost 100 missions with gliding robotic submersibles that autonomously collect and transmit data for up to a month, even under rough conditions. Recently, the scientists deployed one such craft — manufactured by Webb Research — to look for changes associated with global warming in Antarctica.
An autonomous submersible is shown gliding underwater off Antarctica’s coast.
The scientists attached to the craft two hockey puck-shaped sensors from Wet Labs. The first device measured backscatter of red, green and blue light to gauge water clarity and the concentration of suspended inorganic and organic material. The second recorded the level of phytoplankton in the water via its fluorescence response to green-light excitation. A Sea-Bird conductivity, temperature and pressure sensor also was affixed to the submersible. From these parameters, the researchers could calculate salinity and density. By pumping water into and out of its hull, the craft changed its buoyancy and slowly glided into the depths and back to the surface, where it transmitted the data to the team via satellite.
On this mission, information from the submersible addressed several research questions, including how ocean physics was linked to penguin foraging areas around Palmer Station. Data collected on the mission in January is still being analyzed. The researchers emphasize, however, that the technology could make ship-based studies more directed and productive. Next, they plan to develop projects to allow improved biological forecasting in the ocean.
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