title: Environmental variability and biodiversity of megabenthos on the Hebrides Terrace Seamount (Northeast Atlantic).
abstract: We present the first remotely operated vehicle investigation of megabenthic communities (1004-1695 m water depth) on the Hebrides Terrace Seamount (Northeast Atlantic). Conductivity-temperature-depth casts showed rapid light attenuation below the summit and an oceanographic regime on the flanks consistent with an internal tide, and high short-term variability in water temperature, salinity, light attenuation, aragonite and oxygen down to 1500 m deep. Minor changes in species composition (3-14%) were explained by changes in depth, substratum and oceanographic stability, whereas environmental variability explained substantially more variation in species richness (40-56%). Two peaks in species richness occurred, the first at 1300-1400 m where cooler Wyville Thomson Overflow Water (WTOW) mixes with subtropical gyre waters and the second at 1500-1600 m where WTOW mixes with subpolar mode waters. Our results suggest that internal tides, substrate heterogeneity and oceanographic interfaces may enhance biological diversity on this and adjacent seamounts in the Rockall Trough.
authors.affiliation: Centre for Marine Biodiversity, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom.
authors.forename: Lea-Anne
authors.initials: LA
authors.lastname: Henry
authors.affiliation: cole Normale Supérieure de Paris, Département de Biologie, 46 rue d'Ulm, Paris, 75005, France.
authors.forename: Johanne
authors.initials: J
authors.lastname: Vad
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, Hoe, Plymouth, PL1 3DH, United Kingdom.
authors.forename: Helen S
authors.initials: HS
authors.lastname: Findlay
authors.affiliation: Instituto Español de Oceanografía, Centro Oceanográfico de Vigo, Programa de Pesquerías Lejanas, Apartado 1552, 36390 Vigo, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Murillo
authors.affiliation: Institute of Biodiversity, Graham Kerr Building, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Milligan
authors.affiliation: 1] Centre for Marine Biodiversity, Heriot-Watt University, Edinburgh, EH14 4AS, United Kingdom [2] Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll, PA37 1QA, United Kingdom [3] Center for Marine Science, University of North Carolina Wilmington, 601 South College Road, Wilmington, NC 28403-5928, United States of America.
authors.forename: J Murray
authors.initials: JM
authors.lastname: Roberts
mesh_terms: D063147:Animal Distribution; D059001:Aquatic Organisms; D001267:Atlantic Ocean; D044822:Biodiversity; D006363:Hebrides; D010100:Oxygen / Q000737:chemistry; D054712:Salinity; D012623:Seawater / Q000737:chemistry
chemical_list: D010100:Oxygen