MRI: Acquisition of an Acoustic Wave Glider

East Carolina University, Greenville NC

Investigators

Abstract

The Acoustic Wave Glider manufactured by Liquid Robotics, is a mobile, unmanned, quiet, ocean surface vehicle for the study of marine soundscapes and detection of acoustically tagged marine animals. The glider is powered by batteries recharged by solar photovoltaic panels and propelled by wave action, so that long unmanned missions can be achieved at very low cost. The glider can travel along programmed transects for months-long deployments collecting meteorological and ocean data and recording and identifying species that make sounds in the ocean soundscape, including both the natural (geophony and biophony) and anthropogenic (anthropophony) sounds. Some of the species that can be studied with the acoustic sensors on this glider include the endangered Atlantic sturgeon, red drum, striped bass, groupers, bluefin tuna, sharks, endangered right whales and bottlenose dolphins. The instrument package on the glider will allow multiple and simultaneous measurements of the ocean environment (waves using a Datawell MOSE-G1000 wave sensor; currents using a Teledyne RDI Acoustic Doppler Current Profiler; temperature, salinity, depth and dissolved oxygen using a Sea-Bird CTD+DO sensor; and turbidity and phytoplankton abundance using a Turner C-3 pumped fluorometer) and near-surface weather (air temperature, rainfall, wind speed using an Airmar 200WX Weather Station) during missions. An acoustic tag receiver (Vemco VR2C sensor) will be used to detect and track acoustically tagged animals, and a recording hydrophone and analysis system (Decimus PAMBuoy sensor) will record sounds produced by marine animals and classify them. The glider will be used to monitor areas for the presence of sound-producing animals, to avoid noise and other impacts to threatened species in shipping and transportation corridors, to identify and protect fishing areas, and to assess impacts to areas proposed for wave and wind energy development, sand mining areas, and oil and gas leases. Data reports will be relayed from all the glider sensors to land-based computers via satellite and mobile phone modems in near-real-time for analysis, mapping and archival. Our overarching objective with the Acoustic Wave Glider is to document ocean habitats and biologic communities in continental shelf and slope waters to determine static communities (e.g., reefs) and migratory pathways of highly mobile species (e.g., fishes, marine mammals, sea turtles). Secondary objectives include providing data to oceanographers on environmental conditions during normal conditions and storm events to enhance storm prediction models. Storms and rainfall events can be analyzed for their impacts on ocean communities through acoustic analysis of organism responses. Storm events often cannot be sampled by vessels due to danger to life and equipment, but wave gliders are specifically designed to survive and report ambient ocean conditions, even during storm sea states and hurricanes. The glider will be featured at public displays of research at the NC aquariums, including static displays and interactive touch screens of glider tracks are planned. Scientific forums, seminars, and other public events will be scheduled, and glider users will be encouraged to write public interest articles about mission results for news media and magazines. The results of studies based data collected with the glider will be presented at scientific meetings and published in peer-reviewed journals.