Imaging and sampling beneath free-drifting icebergs with a remotely operated vehicle

A commercially available, small (less than 100-kg), remotely operated vehicle (ROV) was modified to image and sample the marine ecosystem surrounding free-drifting icebergs east of the Antarctic Peninsula during three field expeditions in 2005, 2008 and 2009. Modifications included fitting the vehicle with an accessory tool sled, additional thrusters, flotation and significant changes to internal wiring to support a wide array of sensors and samplers. The ROV was re-configured aboard the R/V Nathaniel B. Palmer to perform either general exploration and biological sampling (Bio dives) or water sampling (Chemistry dives). In-situ sensors and a suction sampler were used for Bio dives while a suction pump and hose were fastened along the full length of the ROV tether to enable continuous water sampling adjacent to each iceberg during Chemistry-dives. Details of the ROV system are presented along with a discussion of the 18 dives that explored the sides and bottoms of six different icebergs during the 2009 field expedition.