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De Broyer C.,Royal Belgian Institute Of Natural Sciences | Danis B.,Royal Belgian Institute Of Natural Sciences | Louise A.,National University of Ireland | Martin A.,University of Southampton | And 60 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2011

The IPY sister-projects CAML and SCAR-MarBIN provided a timely opportunity, a strong collaborative framework and an appropriate momentum to attempt assessing the "Known, Unknown and Unknowable" of Antarctic marine biodiversity. To allow assessing the known biodiversity, SCAR-MarBIN "Register of Antarctic Marine Species (RAMS)" was compiled and published by a panel of 64 taxonomic experts. Thanks to this outstanding expertise mobilized for the first time, an accurate list of more than 8100 valid species was compiled and an up-to-date systematic classification comprising more than 16,800 taxon names was established. This taxonomic information is progressively and systematically completed by species occurrence data, provided by literature, taxonomic and biogeographic databases, new data from CAML and other cruises, and museum collections. RAMS primary role was to establish a benchmark of the present taxonomic knowledge of the Southern Ocean biodiversity, particularly important in the context of the growing realization of potential impacts of the global change on Antarctic ecosystems. This, in turn, allowed detecting gaps in knowledge, taxonomic treatment and coverage, and estimating the importance of the taxonomic impediment, as well as the needs for more complete and efficient taxonomic tools. A second, but not less important, role of RAMS was to contribute to the "taxonomic backbone" of the SCAR-MarBIN, OBIS and GBIF networks, to establish a dynamic information system on Antarctic marine biodiversity for the future. The unknown part of the Southern Ocean biodiversity was approached by pointing out what remains to be explored and described in terms of geographical locations and bathymetric zones, habitats, or size classes of organisms. The growing importance of cryptic species is stressed, as they are more and more often detected by molecular studies in several taxa. Relying on RAMS results and on some case studies of particular model groups, the question of the potential number of species that remains to be discovered in the Southern Ocean is discussed. In terms of taxonomic inputs to the census of Southern Ocean biodiversity, the current rate of progress in inventorying the Antarctic marine species as well as the state of taxonomic resources and capacity were assessed. Different ways of improving the taxonomic inputs are suggested. © 2010 Elsevier Ltd.

Kalogeropoulou V.,Hellenic Center for Marine Research | Kalogeropoulou V.,Naturmuseum und Forschungsinstitut Senckenberg | Bett B.J.,UK National Oceanography Center | Gooday A.J.,UK National Oceanography Center | And 3 more authors.
Deep-Sea Research Part II: Topical Studies in Oceanography | Year: 2010

Trends among major metazoan meiofaunal taxa were investigated based on 56 deployments of a multicorer at 10 time points over a period of 11 years (1989-1999) at the Porcupine Abyssal Plain Sustained Observatory site (PAP-SO: 48°50'N 16°30'W, 4850m depth). This area is characterised by a strong seasonality in the deposition of organic matter to the seafloor and by the massive increase in the density of holothurian species since 1996, the so-called 'Amperima event'. Total meiofaunal densities ranged from 346 to 1074ind.×10cm -2 and showed a significant increase with time when time was represented by cruises, years and the 'Amperima period' (1996-1999) vs. the pre-Amperima period (1989-1994). This pattern was driven mainly by the nematodes, which were the dominant taxon (~90% of total abundance). The third most abundant group, the polychaetes, also increased significantly in abundance over the time series, while the ostracods showed a significant decrease. Most other taxa, including the second-ranked group, the copepods (harpacticoids and nauplii), did not exhibit significant temporal changes in abundance. Ordination of taxon composition showed a shift from the pre-Amperima to the Amperima periods, a trend supported by the significant correlation between the x-ordinate and time. The majority (52-75%) of meiofaunal animals inhabited the top 2cm of the 5cm sediment cores analysed. There were significant increases in the proportion of total meiofauna, nematodes and copepods (but not polychaetes) inhabiting the 0-1cm layer over time (represented by cruises) and between the pre-Amperima and Amperima periods in the case of copepods and polychaetes. During the intensively sampled period (1996-1997), there were indications of seasonal changes in the vertical distribution patterns of total meiofauna and nematodes within the sediment. We discuss the potential link between temporal variations in organic matter flux to the seafloor and meiofaunal populations, considering both qualitative and quantitative changes in fluxes and how they may be linked to climate variations. © 2009 Elsevier Ltd.

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