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EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > AQUATIC ECOSYSTEMS > PLANKTON > ZOOPLANKTON

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  • Zooplankton were collected with a Rectangular Midwater Trawl (RMT 8+1 net) from 37 sampling sites on and near the Southern Kerguelen Plateau. Specimens of the euphausiid Thysanoessa macrura were selected for cohort analysis, based on lengths, and allometry (dry weights and lengths). Lipids were extracted from the animals to provide a lipid content (%) as a function of dry weight. A small number of individuals was examined further to produce profiles of the main fatty acids and fatty alcohols. Instantaneous growth rate experiments (IGR) were conducted onboard to determine growth rates of males, females and juveniles.

  • We studied the gut contents of four dominant copepod species (Calanoides acutus, Calanus propinquus, Calanus simillimus and Rhincalanus gigas) during the summer (2014-2015) along a latitudinal gradient (sampled every 5° between 40°S and 65°S) in the Indian sector of the SO. Diatoms were the most abundant food item found in the guts, comprising 24 of the 25 species found, and 15 were common to the four species of copepod studied. Diatoms accounted for the lowest proportion of the diet in the warmer, northern waters while all the large diatoms (e.g. Chaetoceros atlanticus, C. criophilus, C. dichaeta, Corethron spp.) were only found at 65oS. The most frequent species in the guts were the centric diatoms Thalassiosira spp. (4 to 57%) and the pennate diatoms Fragilariopsis kerguelensis (27 to 80%) and Trichoctoxon reinboldii (2 to 50%); proportions varied within a species across locations. These species were found at all sites examined, whereas some diatoms were specific to one copepod species: Asteromphalus spp. (in R. gigas), C. criophilus and C. dichaeta (in C. acutus), Nitzschia lecointei and N. sicula (in C. propinquus).

  • The dataset was developed during a cruise on the Umitaka-maru along the 110 E meridian from Fremantle to the ice edge. At five stations, zooplankton were collected and specimens selected for grazing experiments. They were added to 2L bottles, allowed to acclimate over 24 hours then placed in an onboard incubator and allowed to graze on natural phytoplankton assemblages. Water circulation around the incubator kept the temperature to that of seawater at the time of collection. Shade cloth was used to mimic the light conditions at each site. Where possible 4 replicates were run for each species and 4 control bottles were set up with the same phytoplankton assemblage but with no zooplankton added. Initial subsamples were taken and preserved in Lugol's solution. At the end of each experiment, further subsamples were taken and preserved in Lugol's solution. In the IMAS lab the phytoplankton samples were settled into smaller volumes and processed through a Coulter Counter to obtain the number of cells that had been removed by the plankton (initial conc - final conc). From those values, grazing rates of the species could be calculated for each site along the transect.

  • Metadata record for data from ASAC Project 473 See the link below for public details on this project. Data for this project was primarily collected on two voyages to the Heard Island area - the HIMS voyage (1990), and the FISHOG voyage (1992). The data have been compiled by Angela McGaffin, and can be found in the "processed" folder of the download file. Original datasets are also available in the "Original Datasets" folder. The data primarily consist of CTD data, krill data and zooplankton data. HIMS was a marine science voyage, which travelled to Heard Island in May and June of 1990. FISHOG was a marine science voyage, which travelled to Heard Island and Antarctica from January to March of 1992.

  • 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.

  • This dataset contains scanned copies of the RMT and bottom trawl logs from Voyage 6 1990-91 (AAMBER2) of the Aurora Australis. This was primarily a marine science voyage. Surveys of krill, other zooplankton and pelagic fish were taken in Prydz Bay, Antarctica between January and February 1991. 177 midwater trawls were successfully completed at 59 stations. Midwater fish were sampled using an International Young Gadoid Pelagic Trawl (IYGPT). At each station, hauls were taken at depths of 20-30m, approximately halfway down the water column, and 20-30m above the bottom. At six stations, the lowest sample was duplicated using a light fitted to the net. Where samples were made off the shelf, standard depths of 20-30m, 400m, and 800m were fished. All hauls were of 30 minutes fishing time. Bottom trawls were made using a 35m headline length otter trawl fitted with 40cm diameter bobbin gear. A 2" mesh cod end liner was used to retain small fish. On both nets, a Simrad trawl surveillance sonar was used.

  • This data set includes abundance and distribution of sea ice and water column micro-invertebrates. Data was collected form 8 stations over the course of the SIPEX 2 voyage. The data for this project consists of 2 separate collection regimes: 1. Ice cores - a number of ice were taken at stations 1-6, using a 15cm corer, they were sectioned and dissolved in filtered seawater before being fixed in formalin. At Station 6 sufficient biomass was present in the bottom 10cm of some cores to allow microscopic separation of copepod species, which were then frozen for stable isotope analysis (SIA). 2. Lazer optical plankton counter (LOPC) was deployed at stations 2 to 7 either from ice holes (IH) or from the trawl Deck (TD) to depths of 60m or 100m. These deployments were made throughout the day where possible and were accompanied by a 100um plankton net . Each deployment consisted of 2 drops for both the LOPC and the net. Collected plankton were filtered onto 50um mesh and backwashed into vials before being fixed in 5% formalin. All LOPC files .bin will require LOPC program manufactured by ODIM Rolls Royce Nova Scotia. These files are read to format .dat which maybe opened as a .txt file

  • 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

  • This dataset contains data files, processing templates and documentation relating to the BROKE-West multifrequency echosounder (acoustic) survey carried out from the RSV Aurora Australis in the austral summer of 2005/06 (ASAC project 2655). The primary aim of the acoustic survey was to describe the distribution and abundance of Antarctic krill (Euphausia superba) in CCAMLR Division 58.4.2. However, these data are also relevant for studies of other sound-scattering targets detected by the echosounder system, for example other pelagic taxa or the seafloor. The dataset is a collection of *.csv data files, *.ev processing files and *.pdf documentation files, organised into 4 categories: 1. Acoustic survey: data files relating to the transects undertaken for the acoustic survey 2. Acoustic data processing: metadata files, processing templates and documentation relating to the collection and processing of the acoustic data 3. Acoustic results: results arising from the processing of the raw data. The raw data are described in a separate metadata record - "AAD Hydroacoustics hard disks - data collected from Southern Ocean cruises..." 4. Ancillary data: additional non-acoustic data used during the processing of the acoustic data The file "data_fields.pdf" lists and describes the fields in each of the *.csv data files. The file "processing_methods.pdf" provides a synopsis of the methods by which the raw acoustic data were collected and processed. The BROKE-West survey was conducted on voyage 3 of the Aurora Australis during the 2005-3006 season. It was intended to be a comprehensive biological and oceanographic survey of the region between 30 degrees and 80 degrees east.

  • Zooplankton were collected with a Rectangular Midwater Trawl (RMT 8+1 net) from 37 sampling sites on and near the Southern Kerguelen Plateau. The contents of each net were preserved in 5% buffered formaldehyde. This dataset covers the counts of the contents of the RMT1 net. The contents were split in the laboratory using a Motoda Box and then identified and counted under a Leica M165C stereo-microscope. A flow meter attached to the mouth of the RMT 8 was used to record the volume of seawater passing through the net, and this volume was converted to water passing through the RMT 1 by applying the conversion factor of 2.027357. The organisms in the samples were identified to the lowest taxonomic level possible. For copepods and euphausiids this level was to species, and generally to sex and/or development stage. For other groups, the identifications were to high levels such as Family or Order.