title: Insights into the abundance and diversity of abyssal megafauna in a polymetallic-nodule region in the eastern Clarion-Clipperton Zone.
abstract: There is growing interest in mining polymetallic nodules in the abyssal Clarion-Clipperton Zone (CCZ) in the Pacific. Nonetheless, benthic communities in this region remain poorly known. The ABYSSLINE Project is conducting benthic biological baseline surveys for the UK Seabed Resources Ltd. exploration contract area (UK-1) in the CCZ. Using a Remotely Operated Vehicle, we surveyed megafauna at four sites within a 900 km(2) stratum in the UK-1 contract area, and at a site ~250 km east of the UK-1 area, allowing us to make the first estimates of abundance and diversity. We distinguished 170 morphotypes within the UK-1 contract area but species-richness estimators suggest this could be as high as 229. Megafaunal abundance averaged 1.48 ind. m(-2). Seven of 12 collected metazoan species were new to science, and four belonged to new genera. Approximately half of the morphotypes occurred only on polymetallic nodules. There were weak, but statistically significant, positive correlations between megafaunal and nodule abundance. Eastern-CCZ megafaunal diversity is high relative to two abyssal datasets from other regions, however comparisons with CCZ and DISCOL datasets are problematic given the lack of standardised methods and taxonomy. We postulate that CCZ megafaunal diversity is driven in part by habitat heterogeneity.
authors.affiliation: Department of Oceanography, University of Hawai'i at Mānoa, 1000 Pope Road, Honolulu, HI 96822 USA.
authors.forename: Diva J
authors.initials: DJ
authors.lastname: Amon
authors.affiliation: Department of Oceanography, University of Hawai'i at Mānoa, 1000 Pope Road, Honolulu, HI 96822 USA.
authors.forename: Amanda F
authors.initials: AF
authors.lastname: Ziegler
authors.affiliation: Uni Research, Thormøhlensgate 55, 5008 Bergen, Norway.|Department of Marine Sciences, University of Gothenburg, Box 463, 40530 Gothenburg, Sweden.
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Dahlgren
authors.affiliation: Life Sciences Department, Natural History Museum, Cromwell Rd, London SW7 5BD, UK.
authors.forename: Adrian G
authors.initials: AG
authors.lastname: Glover
authors.affiliation: National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Goineau
authors.affiliation: National Oceanography Centre, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gooday
authors.affiliation: Life Sciences Department, Natural History Museum, Cromwell Rd, London SW7 5BD, UK.
authors.forename: Helena
authors.initials: H
authors.lastname: Wiklund
authors.affiliation: Department of Oceanography, University of Hawai'i at Mānoa, 1000 Pope Road, Honolulu, HI 96822 USA.
authors.forename: Craig R
authors.initials: CR
authors.lastname: Smith
mesh_terms: D000818:Animals; D044822:Biodiversity; D005843:Geography; D007091:Image Processing, Computer-Assisted; D008670:Metals / Q000378:metabolism*; D010140:Pacific Ocean; D013045:Species Specificity; D006113:United Kingdom
chemical_list: D008670:Metals