Marine Ecology. ISSN 0173-9565 SPECIAL TOPIC Biological structures as a source of habitat heterogeneity and biodiversity on the deep ocean margins Lene Buhl-Mortensen1, Ann Vanreusel2, Andrew J. Gooday3, Lisa A. Levin4, Imants G. Priede5,Pa˚ l Buhl-Mortensen1, Hendrik Gheerardyn2, Nicola J. King5 & Maarten Raes2 1 Institute of Marine Research, Benthic habitat group, Bergen, Norway 2 Ghent University, Marine Biology research group, Belgium 3 National Oceanography Centre Southampton, Southampton, UK 4 Integrative Oceanography Division, Scripps Institution of Oceanography, University of California, La Jolla, CA, USA 5 Oceanlab, University of Aberdeen, Newburgh, Aberdeenshire, UK Keywords Abstract Biodiversity; biotic structures; commensal; continental slope; deep sea; deep-water coral; Biological structures exert a major influence on species diversity at both local and ecosystem engineering; sponge reefs; regional scales on deep continental margins. Some organisms use other species as xenophyophores. substrates for attachment, shelter, feeding or parasitism, but there may also be mutual benefits from the association. Here, we highlight the structural attributes Correspondence and biotic effects of the habitats that corals, sea pens, sponges and xenophyo- Lene Buhl-Mortensen, Institute of Marine phores offer other organisms. The environmental setting of the biological struc- Research, Benthic habitat group, P.O. Box 1870 Nordnes, N-5817 Bergen, Norway tures influences their species composition. The importance of benthic species as E-mail:
[email protected] substrates seems to increase with depth as the complexity of the surrounding geological substrate and food supply decline. There are marked differences in the Accepted: 30 December 2009 degree of mutualistic relationships between habitat-forming taxa. This is espe- cially evident for scleractinian corals, which have high numbers of facultative doi:10.1111/j.1439-0485.2010.00359.x associates (commensals) and few obligate associates (mutualists), and gorgonians, with their few commensals and many obligate associates.