An orange Roughy in a coral reef taken by the Isis ROV
(September 16, 2015) The first true three-dimensional picture of submarine canyon habitats has been produced using a unique combination of marine robotics and ship-based measurements. The information captured in this new set of maps ranges in scale from the 200km canyon down to the size of an individual cold-water coral polyp, and will be used to inform the management of the only English Marine Conservation Zone in deep water.
This ‘nested map’ is the result of a recent scientific expedition to the Whittard Canyon in the Bay of Biscay, led by the National Oceanography Centre (NOC). It works in a way not unlike a set of Russian dolls, with the most detailed map sitting within a larger scale one, which sits within a larger map still.
Submarine canyons are some of the most complex deep-sea environments on this planet, and are known to be potential biodiversity hotspots. Similar to canyons on land, submarine canyons can have steep flanks, with vertical cliffs and overhanging rock formations. Until recently these parts were out of reach for traditional types of marine equipment, which made them the 'forgotten habitats' of the deep sea. By using unique robot technology to collect data in these ‘hard-to-reach’ areas, the results of this expedition will lead to a better understanding of the biodiversity patterns in the canyon and of the processes that drive them.
Rich cold-water coral reef in the Whittard Canyon area by the Isis ROV
Echo-sounders on the RRS James Cook were used to create a 200km map of the canyon with a 50m pixel resolution. Using a newly-developed sideways-directed echo-sounder, the Autosub6000 robot-sub, maintained by the NOC, was able to map vertical walls within the canyon with a resolution of 3-5m per pixel. At the same time Isis, the NOC-maintained Remotely Operated Vehicle, was lowered from the RRS James Cook on a tether to record high definition video and to collect biological and geological samples from vertical and overhanging locations. Echo-sound data collected with Isis was also used to create the most detailed map of the three, with a resolution of 10-20cm.
Dr Veerle Huvenne from the NOC, who led the 5-week expedition, said: "Our robot vehicles imaged rich communities of cold-water corals, clams, deep-sea oysters and their associated fauna, including a broad range of fish species. We also captured amazing footage of Blue Sharks and Swordfish when the Isis marine robot was travelling to and from the seabed.