title: First insights into the biodiversity and biogeography of the Southern Ocean deep sea.
abstract: Shallow marine benthic communities around Antarctica show high levels of endemism, gigantism, slow growth, longevity and late maturity, as well as adaptive radiations that have generated considerable biodiversity in some taxa. The deeper parts of the Southern Ocean exhibit some unique environmental features, including a very deep continental shelf and a weakly stratified water column, and are the source for much of the deep water in the world ocean. These features suggest that deep-sea faunas around the Antarctic may be related both to adjacent shelf communities and to those in other oceans. Unlike shallow-water Antarctic benthic communities, however, little is known about life in this vast deep-sea region. Here, we report new data from recent sampling expeditions in the deep Weddell Sea and adjacent areas (748-6,348 m water depth) that reveal high levels of new biodiversity; for example, 674 isopods species, of which 585 were new to science. Bathymetric and biogeographic trends varied between taxa. In groups such as the isopods and polychaetes, slope assemblages included species that have invaded from the shelf. In other taxa, the shelf and slope assemblages were more distinct. Abyssal faunas tended to have stronger links to other oceans, particularly the Atlantic, but mainly in taxa with good dispersal capabilities, such as the Foraminifera. The isopods, ostracods and nematodes, which are poor dispersers, include many species currently known only from the Southern Ocean. Our findings challenge suggestions that deep-sea diversity is depressed in the Southern Ocean and provide a basis for exploring the evolutionary significance of the varied biogeographic patterns observed in this remote environment.
authors.affiliation: Zoological Museum Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany. abrandt@zoologie.uni-hamburg.de
authors.forename: Angelika
authors.initials: A
authors.lastname: Brandt
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gooday
authors.forename: Simone N
authors.initials: SN
authors.lastname: Brandão
authors.forename: Saskia
authors.initials: S
authors.lastname: Brix
authors.forename: Wiebke
authors.initials: W
authors.lastname: Brökeland
authors.forename: Tomas
authors.initials: T
authors.lastname: Cedhagen
authors.forename: Madhumita
authors.initials: M
authors.lastname: Choudhury
authors.forename: Nils
authors.initials: N
authors.lastname: Cornelius
authors.forename: Bruno
authors.initials: B
authors.lastname: Danis
authors.forename: Ilse
authors.initials: I
authors.lastname: De Mesel
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Diaz
authors.forename: David C
authors.initials: DC
authors.lastname: Gillan
authors.forename: Brigitte
authors.initials: B
authors.lastname: Ebbe
authors.forename: John A
authors.initials: JA
authors.lastname: Howe
authors.forename: Dorte
authors.initials: D
authors.lastname: Janussen
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kaiser
authors.forename: Katrin
authors.initials: K
authors.lastname: Linse
authors.forename: Marina
authors.initials: M
authors.lastname: Malyutina
authors.forename: Jan
authors.initials: J
authors.lastname: Pawlowski
authors.forename: Michael
authors.initials: M
authors.lastname: Raupach
authors.forename: Ann
authors.initials: A
authors.lastname: Vanreusel
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D044822:Biodiversity; D005843:Geography; D007448:Invertebrates / Q000145:classification / Q000502:physiology; D008386:Marine Biology; D009792:Oceans and Seas; D010802:Phylogeny; D012623:Seawater