Octopus feeding traces from the AURORA seamount, high Arctic
Description
The Aurora hydrothermal field sits in the westernmost segment of the Gakkel Ridge within the Western Volcanic Zone which extends for 220 km from 7°W to 3°E. The Aurora field was first located associated with one such volcanic mound as part of the InterRidge two-icebreaker AMORE expedition in 2001, at 82°53'N, 6°15'W. During 2019, as part of the 'HACON' research program, the icebreaker RV Kronprins Hakon visited the seamount, using date from previous expeditions to conduct 10 Ocean Floor Observation and Bathymetry System (OFOBS) drift stations across the summit and flanks of the seamount. The Ocean Floor Observation and Bathymetry System (OFOBS) (Purser et al., 2018) is a towed underwater camera sled equipped with both a high resolution photo-camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-camera (iSiTEC, Sony FCB-H11). The cameras are mounted on a steel frame (140L x 92W x 135H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three laser pointers at a distance of 50 cm from each other that were used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOS during deployments. Although the research aim of the OFOBS tows was to investigate hydrothermalism across the Aurora field, the cameras also recorded 106 traces left on the seafloor made by cirrate octopusses during their feeding cycle from within approximately 5100 images of the seafloor. The high abundance of these traces is , at time of writing, unique from arctic research expeditions. This dataset contains a .zip file derived from the full image set collected during the HK19 expedition (and available from the PANGAEA link below). This contains the raw images, processed with Adobe Photoshop CS6.0 to give an exposure offset of +0.2 and a gamma correction of 2.0. At these levels the octagonal traces left by the octopusses on the seafloor during feeding were more apparent. All processed images were examined using the PAPARA(ZZ)I software application (Marcon and Purser, 2017) and "fresh" and "degraded" traces both logged and measured. The output from this stage is provided in the two attached .xlsx documents. FILES WITHIN THIS DATASET: "octotrace.zip" - file contains all seafloor images within which octopus traces were visible "Tracedimensions.xlsx" - file contains as columns the name of each image (image_name), trace type (Trace type) and width of each octogonal trace, in meters (Octo trace width). "OctopusAbundances.xlsx" - file contains as columns image name (image_name), image area captured by each image (imagearea_m2), number of live octopus (Live octopus), number of degraded (Degraded_octopus_trace), Fresh (Fresh octopus trace) and total number of octopus traces (Total octopus traces).
Files
Steps to reproduce
All data within this dataset was collected with the Ocean Floor Observation and Bathymetry System (OFOBS) cameras.