https://dsbs2018.org/
Cold-water coral communities on rocky walls: distribution from global to colony scales
Katleen Robert 1, Daniel O.B. Jones 2, Aggeliki Georgiopoulou 3 and Veerle A.I Huvenne 2
1. Fisheries and Marine Institute of Memorial University, St. John’s, Canada
2. National Oceanography Centre, Southampton, UK
3. University College Dublin, Dublin, Ireland
ABSTRACT
Similar to their shallow water counter parts, vertical and overhanging walls in the deep sea provide a different set of environmental conditions than the surrounding terrain. Because of their geometry, these habitats can also harbour highly diverse communities and provide protection to vulnerable cold-water coral ecosystems from trawling activities. As such, it is important to assess their global importance and understand their ecology. In this study, we assess coral wall systems at three scales: (1) review globally available datasets (bathymetry, presence records, habitat suitability models and geomorphic catalogues), (2) analyse community patterns of megafaunal species inhabiting six walls in the Northeast Atlantic and (3) reconstruct in three dimensions and at very high resolution (<1 cm) a section of a wall using photogrammetry techniques. Globally we found over 6,000 features likely to harbour rocky walls and cold-water corals, demonstrating their importance. The investigated walls showed significant differences in diversity and community composition, while within individual walls, differences in ecological niche could be demonstrated between closely-related taxa. Rocky walls represent an important cold-water coral habitat with significant differences in species composition across walls within a region, illustrating their role in driving diversity patterns. These results highlight the role of terrain heterogeneity in driving cold-water coral spatial patterns over a range of scales and highlight the need to consider deep-sea vertical habitats in current conservation efforts. This work is part of the ERC CODEMAP project (Starting Grant no 258482) and data were collected during the CODEMAP2015 cruise and the SORBEH expedition (Marine Institute, Ireland).