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EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > PELAGIC

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  • This dataset is a document describing the Pelagic Tunicates of the Southern Ocean. It lists all the known Southern Ocean species and with illustrated diagrams provides a guide to their taxonomic identification. The document is available for download as a pdf from the provided URL.

  • This layer is a circumpolar, pelagic regionalisation of the Southern Ocean south of 40 degrees S, based on sea surface temperature, depth, and sea ice information. The results show a series of latitudinal bands in open ocean areas, consistent with the oceanic fronts. Around islands and continents, the spatial scale of the patterns is finer, and is driven by variations in depth and sea ice. The processing methods follow those of Grant et al. (2006) and the CCAMLR Bioregionalisation Workshop (SC-CAMLR-XXVI 2007). Briefly, a non-hierarchical clustering algorithm was used to reduce the full set of grid cells to 250 clusters. These 250 clusters were then further refined using a hierarchical (UPGMA) clustering algorithm. The first, non-hierarchical, clustering step is an efficient way of reducing the large number of grid cells, so that the subsequent hierarchical clustering step is tractable. The hierarchical clustering algorithm produces a dendrogram, which can be used to guide the clustering process (e.g. choices of data layers and number of clusters) but is difficult to use with large data sets. Analyses were conducted in Matlab (Mathworks, Natick MA, 2011) and R (R Foundation for Statistical Computing, Vienna 2009). Three variables were used for the pelagic regionalisation: sea surface temperature (SST), depth, and sea ice cover. Sea surface temperature was used as a general indicator of water masses and of Southern Ocean fronts (Moore et al. 1999, Kostianoy et al. 2004). Sea surface height (SSH) from satellite altimetry is also commonly used for this purpose (e.g. Sokolov and Rintoul 2009), and may give front positions that better match those from subsurface hydrography than does SST. However, SSH data has incomplete coverage in some near-coastal areas (particularly in the Weddell and Ross seas) and so in the interests of completeness, SST was used here. During the hierarchical clustering step, singleton clusters (clusters comprised of only one datum) were merged back into their parent cluster (5 instances, in cluster groups 2, 3, 8, and 13). Additionally, two branches of the dendrogram relating to temperate shelf areas (around South America, New Zealand, and Tasmania) were merged to reduce detail in these areas (since such detail is largely irrelevant in the broader Southern Ocean context).

  • This dataset is a document describing the Pelagic Polychaetes of the Southern Ocean. It lists all the known species and with illustrated diagrams provides a guide to their taxonomic identification. The document is available for download as a pdf from the provided URL.

  • This dataset contains environmental layers used to model the predicted distribution of demersal fish bioregions for the paper: Hill et al. (2020) Determining Marine Bioregions: A comparison of quantitative approaches, Methods in Ecology and Evolution. It contains climatological variables from satellite and modelled data that represent sea floor and sea surface conditions likely to affect the distribution of demersal fish including: depth, slope, seafloor temperatures, seafloor current, seafloor nitrate, sea surface temperature, chlorophyll-a standard deviation and sea surface height standard deviation. Layers are presented at 0.1 degree resolution. "prediction_space" is a Rda file for R that consists of two objects: env_raster: a raster stack of the environmental layers pred_sp: a data.frame version of the env_raster where some variables have been transformed for statistical analysis and bioregion prediction. "Env_data_sources.xlsx" contains a description of each environmental variable and it's source.

  • This dataset is a document describing the Decapoda of the Southern Ocean. It lists all the known species and with illustrated diagrams provides a guide to their taxonomic identification. The document is available for download as a pdf from the provided URL.

  • Taken from the abstracts of the referenced papers: Distribution patterns of pelagic fish, larvae and juveniles collected by RMT trawls during BROKE survey to CCAMLR Division 58.4.1 were investigated. Nearly 2000 individuals, weighing 1210 g, were collected from approximately 1.5 million cubic metres of the upper 200 m of ocean, supporting the theory that Antarctic ichthyoplankton has low biomass. The collection consisted mainly of P. antarcticum larvae and juveniles and E. antarctica sub-adults, with a range of other notothenioid fish and myctophids. Three distinct biogeographic zones, with characteristic ichthyo- and zooplankton assemblages, were identified. The Oceanic Zone was dominated by myctophids and, in the western reaches, the paralepidid N. coasti. The shelf break zone comprised of myctophids, and the juveniles of notothenioid fish. The shelf zone consisted of notothenioid juveniles and sub-adults. Characteristic water masses and associated zooplankton assemblages were found throughout these three zones. Analysis of fish stomach contents indicated feeding on locally abundant zooplankton taxa. There was niche-partitioning of prey taxa and size classes, between both sympatric species and between different ontogenetic stages. Fish distributions corresponded to known patterns, and extended the geographic range of several species. ##### Zooplankton data from routine 0-200 m oblique trawls were analysed using cluster analysis and non-metric multidimensional scaling to define the communities in Eastern Antarctica (80-150 E), their distribution patterns, indicator species, and species affinities. Three communities were defined based on routine trawls. The Main Oceanic Community comprising herbivorous copepods, chaetognaths, and the euphausiid Thysanoessa macrura dominated the area west of 120 E. The area east of 120 E was dominated by Salpa thompsoni. The third community located in the neritic zone was dominated by Euphausia crystallorophias. Antarctic krill Euphausia superba did not form a distinct community in its own right, unlike previous observations in Prydz Bay. Krill were distributed throughout most of the survey area but generally in higher abundances towards the shelf break. Overall, krill abundance was low compared with previous net surveys in Prydz Bay. Three main types of assemblages were identified based on target trawls. The first group was dominated by krill (mean 1149 individuals per 1000 cubic metres) which represented greater than 99% of Group 1 catches in terms of numbers and biomass. Group 2 comprised the bulk of target trawls and comprised a wide diversity of species typical of the main oceanic community, with a mean abundance approximately half of that observed in the routine trawls. The third group comprised trawls in the neritic zone dominated by E. crystallorophias. No salp-dominated aggregation was found. While E. superba did not dominate a distinct community geographically as seen in previous Prydz Bay surveys, it did dominate discrete layers or aggregations, showing that both horizontal and vertical separation of communities exist. ##### The download file contains the following documents: 199596040Composition.csv 199596040Density.csv 199596040Biomass.csv

  • A series of 6 sets of midwater trawls in Prydz Bay. Each trawl set took place over a 24 hour period to test the extent of diurnal vertical migration in P. antarcticum. Part of the KROCK cruise of Aurora Australis. These data have been incorporated into an 'historical fish database' available for download at the URL given below (Access Database). These data have also been included in the Australian Antarctic Data Centre's Biodiversity database, and have been submitted to GBIF and OBIS (Global Biodiversity Information Facility, and Ocean Biogeographic Information System). The fields in this dataset are: Species Cruise Start Date End Date Sampling Date Vessel Name Fishing Area Latitude Longitude Gear Length Weight Sex Gonad Weight Stomach Weight

  • This dataset is a document describing the pelagic Nemerteans of the Southern Ocean. It lists the 11 known pelagic Southern Ocean species and with illustrated diagrams provides a guide to their taxonomic identification and distribution. The document is available for download as a pdf from the provided URL.

  • This dataset is a document describing the Ctenophores of the Southern Ocean. It lists all the known species and with illustrated diagrams provides a guide to their taxonomic identification. The document is available for download as a pdf from the provided URL.

  • This dataset is a document describing the Chaetognaths of the Southern Ocean. The synonymy, diagnostic characters, geographical and bathymetric distribution of each species is given together with an illustration of body, head and a seminal vesicle, and a distribution map. The document is available for download as a pdf from the provided URL.