Cold-water coral habitats in submarine canyons

Submarine canyons are the main transport pathways between the shelf and deep ocean. They often form biodiversity hotspots, as their steep terrain, unique oceanography and sediment dynamic regimes create a variety of niches that attract a wide range of fauna. One of the most iconic species groups are cold-water corals, types of coral that can live without symbiotic algae. They are important habitat-forming organisms in the deep sea, and may act as nursery grounds for commercial fish species (Roberts et al., 2009). However, they are among the Vulnerable Marine Ecosystems listed by the UN, due to impacts of bottom trawling (Puig et al., 2014).
In addition to the better known cold-water coral reefs found along continental margins, cold-water corals are increasingly discovered in submarine canyons, which focus currents carrying increased organic matter concentrations crucial for the corals' subsistence. As a result of the inaccessibility of this complex environment, the processes of cold-water coral habitat formation in submarine canyons are poorly understood. Why are certain locations colonised by small patches, while in other locations large reefs or hanging gardens can be found (Huvenne et al., 2011)? Why are certain species dominating specific parts of a canyon? How does the interplay between sediment transport, geomorphology and oceanography govern their occurrence? Using a unique dataset gathered by a suite of cutting-edge deep-sea robotic vehicles that can work in the extreme canyon environment (the Autosub6000 Autonomous Underwater Vehicle (AUV) and ISIS Remotely Operated Vehicle (ROV) from NOC and a bouyancy-driven ocean glider from UEA), this PhD will bring insight in the nature, morphology, distribution and dynamics of cold-water coral habitats in submarine canyons, with the ultimate aim to support conservation measures.