title: Changes in nematode communities in different physiographic sites of the condor seamount (north-East atlantic ocean) and adjacent sediments.
abstract: Several seamounts are known as 'oases' of high abundances and biomass and hotspots of biodiversity in contrast to the surrounding deep-sea environments. Recent studies have indicated that each single seamount can exhibit a high intricate habitat turnover. Information on alpha and beta diversity of single seamount is needed in order to fully understand seamounts contribution to regional and global biodiversity. However, while most of the seamount research has been focused on summits, studies considering the whole seamount structure are still rather poor. In the present study we analysed abundance, biomass and diversity of nematodes collected in distinct physiographic sites and surrounding sediments of the Condor Seamount (Azores, North-East Atlantic Ocean). Our study revealed higher nematode biomass in the seamount bases and values 10 times higher in the Condor sediments than in the far-field site. Although biodiversity indices did not showed significant differences comparing seamount sites and far-field sites, significant differences were observed in term of nematode composition. The Condor summit harboured a completely different nematode community when compared to the other seamount sites, with a high number of exclusive species and important differences in term of nematode trophic diversity. The oceanographic conditions observed around the Condor Seamount and the associated sediment mixing, together with the high quality of food resources available in seamount base could explain the observed patterns. Our results support the hypothesis that seamounts maintain high biodiversity through heightened beta diversity and showed that not only summits but also seamount bases can support rich benthic community in terms of standing stocks and diversity. Furthermore functional diversity of nematodes strongly depends on environmental conditions link to the local setting and seamount structure. This finding should be considered in future studies on seamounts, especially in view of the potential impacts due to current and future anthropogenic threats.
authors.affiliation: Centre of IMAR of the University of the Azores & LARSyS Associated Laboratory, PT-9901-862 Horta, Azores, Portugal; IFREMER, Centre Brest, REM/EEP/LEP, Institut Carnot Ifremer-EDROME, ZI de la pointe du diable, CS10070, Plouzané, France; Université de Brest, Institut Universitaire Européen de la Mer, Laboratoire des sciences de l'environnement marin (UMR6539 CNRS/IRD/UBO), Plouzané, France.
authors.forename: Daniela
authors.initials: D
authors.lastname: Zeppilli
authors.affiliation: Centre of IMAR of the University of the Azores & LARSyS Associated Laboratory, PT-9901-862 Horta, Azores, Portugal; Institute of Marine Sciences - National Research Council (ISMAR-CNR), Arsenale - Tesa 104, Castello 2737/F, Venezia, Italy.
authors.forename: Lucia
authors.initials: L
authors.lastname: Bongiorni
authors.affiliation: Centre of IMAR of the University of the Azores & LARSyS Associated Laboratory, PT-9901-862 Horta, Azores, Portugal; Department of Ocenography and Fisheries of the University of the Azores, PT-9901-862 Horta, Azores, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Serrão Santos
authors.affiliation: Department of Biology, Marine Biology section, Ghent University, Krijgslaan 281, S8, Ghent, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Vanreusel
mesh_terms: D000818:Animals; D059001:Aquatic Organisms / Q000502:physiology*; D001267:Atlantic Ocean; D044822:Biodiversity; D018533:Biomass; D019015:Geologic Sediments; D009348:Nematoda / Q000502:physiology*