Seabed imagery from IN2017_V01, Sabrina Seafloor survey, East Antarctica

• Main Authors: Post, A.L., Armand, L., O'Brien, P.E.
• Format: Dataset
• Language: English
• Published: Commonwealth of Australia (Geoscience Australia) 2018
• Subjects: East Antarctica; seafloor; marine ecology; Kongsberg; Sabrina Coast; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.4225/25/5ab2dc0b1000b; http://pid.geoscience.gov.au/dataset/ga/116582

Six camera tow transects were completed during survey IN2017-V01 on the RV Investigator in January to March 2017. This survey focussed on the upper slope and outer continental shelf on the Sabrina Coast seafloor in East Antarctica. Camera tows targeted seafloor depths between 480 and 1680 m. Imagery was collected using the Marine National Facilities Deep Tow Camera. This system collects oblique downward facing still images with a Canon 1DX and high definition video with a Canon C300. Four DSP&L 3150 High Output SeaLite Sphere lights were used, with MicroSeaLasers providing a 10cm scale guide on the images. Several sensors are also attached to the towed body, including a SBE 37 for CTD measurements, a Kongsberg Mesotech 1007D altimeter, a Druck PMP 5074 pressure sensor and two Sonardyne USBLs for locational accuracy of the towed body. The USBL failed for tow A008CAM02, with locations recorded as ships position instead and camera position based on layback calculations. Images failed to record on A004CAM01, with only 2 images saved. Due to a timing error between the images and the other sensors, there is an offset between the CTD, altimeter and pressure data and the images. This is currently being resolved by the MNF. Tows were designed to run down slope to reduce potential for colliding with the bottom. All tows were run with a ship speed over the ground of approximately 2 kt. All still images were saved in jpeg format with video footage recorded to HD1080i50 format. The video data is unclipped and includes descent and ascent in the water column. Following collection still images were colour corrected in Adobe Photoshop to remove the blue bias.