ROV-based Revolver Marker Dropper for Consistent Seafloor Surveying

• Main Authors: Lehmenhecker, S., Wulff, T.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Compass Publications 2012
• Subjects: Arctic; Arctic Ocean; Alfred Wegener Institute; Fram Strait; North Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/39791/; https://oceanrep.geomar.de/id/eprint/39791/1/Lehmenhecker.pdf; http://www.sea-technology.com/features/2012/0712/rov_revolver.php

As part of an Arctic expedition of the RV Polarstern in July and August 2011 to Fram Strait, a deep-sea revolver marker dropper (RMD), developed by the Alfred Wegener Institute for Polar and Marine Research (AWI), was deployed around 2,500 meters depth on the ROV Kiel 6000 to mark a 350-meter transect for repeated seafloor visual observations. Temporal variations in spatial patterns of benthic epi- and megafauna organisms have been monitored since 1997 at HAUSGARTEN, AWI's deep-sea observatory for detecting and tracking the impact of large-scale environmental changes in the transition zone between the northern North Atlantic and the central Arctic Ocean. High-resolution pictures of the seafloor and its inhabitants were taken almost annually at approximately 7.5-meter intervals using a towed photo and video ocean floor observation system. However, as a towed system could never cover the exact same deep-sea line, the institute decided to conduct comparable visual observations over time with an ROV-based vertical camera system along a defined, shorter transect. The RMD was developed to mark this transect, deploying a multitude of tags at about 10-meter intervals, which allows the ROV pilot to follow the transect from one marker to the next. This tool will ensure capturing exactly the same area over time in seafloor surveys.