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EARTH SCIENCE > OCEANS > OCEAN CHEMISTRY > STABLE ISOTOPES

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  • This data features stable carbon and nitrogen isotopes of co-occurring Southern Ocean pteropods in order to estimate and compare their Bayesian isotopic niches. Other data includes station number, latitude and longitude, species names and sample ID. Details for each column are as follows: A: "species" - Species analysed including, "clio" = Clio pyramidata f. sulcata; "clione" = Clione limacina antarctica; "spongio" = Spongiobranchaea australis; "Large-fraction POM" = large-fraction particulate organic matter; "Small-fraction POM" = small-fraction particulate organic matter B: "speciesID" - Sample ID = unique identifier from Central Science Laboratory, University of Tasmania C: "station" = CTD number (KAxis research voyage) D: "date" = Date of sample (RMT-8 net trawl, KAxis research voyage) E: "lat" = Latitude (degS) F: "long" = Longitude (degE) G: "%C" = percent carbon (no unit) H: "%N" = percent nitrogen (no unit) I: "C:N (bulk)" = uncorrected (raw) carbon-to-nitrogen ratio (no unit) J: "delta 13C (bulk)" = uncorrected (raw) stable carbon isotope values (‰) H: "delta 15N (bulk)" = uncorrected (raw) stable nitrogen isotope values (‰) L: "notes" = samples may be duplicated or triplicated M: "atomic C:N" = C:N (bulk) x 14/12 (no unit) N: "atomic L" = 93/(1+ (1/((0.246 x atomic C:N) - 0.775))) O: "L" = 93/(1+(1/((0.246 x C:N (bulk) - 0.775))) P: "delta 13C (Kiljunen)" = delta 13C (bulk) corrected using formula by Kiljunen et al. 2006 Q: "delta 13C (atomic Kiljunen)" = delta 13C (bulk) corrected using formula by Kiljunen et al. 2006 and atomic L value (column N) R: "delta 13C (Post)" = delta 13C (bulk) corrected using formula by Post et al. 2007 S: "delta 13C (Weldrick)" = delta 13C (bulk) corrected using formula by Weldrick et al. 2019 T: "delta 13C (atomic Smyntek)" = delta 13C (bulk) corrected using formula by Smyntek et al. 2007 and atomic L value (column N) U: "delta 13C (Smyntek)" = delta 13C (bulk) corrected using formula by Smyntek et al. 2007 V: "delta 13C (Logan)" = delta 13C (bulk) corrected using formula by Logan et al. 2008 W: "delta 13C (Syvaranta)" = delta 13C (bulk) corrected using formula by Syvaranta and Rautio 2010 The analysis is featured within a recently accepted paper titled "Trophodynamics of Southern Ocean pteropods on the southern Kerguelen Plateau" peer-reviewed for Ecology and Evolution (2019). It is based on samples collected during the KAxis research voyage, 2015/16.

  • Data shows gross body measurements of lantern shellfish (Laternula elliptica) collected by divers at McGrady Cove; Brown Bay Inner, and Shannon Bay. Measurements include length, width, and height of shell and weight with shell on and shell off.

  • Data shows carbon and nitrogen stable isotope concentration in siphon tissue of laternula elliptica from three sites adjacent to Casey Station. McGrady Cove, Brown Bay Inner and Shannon Bay. All shellfish were collected by divers during the 2014/15 summer season. Samples were sent to Cornell University Stable Isotope laboratory for analysis.

  • Overview of the project and objectives: To investigate whether nitrate uptake and processes other than nitrate uptake by phytoplankton are significant and show spatial variability possibly induced by varying availability of Fe and other parameters in the region, seawater was collected from CTD (Conductivity, Temperature and Depth) and TMR (Trace Metals Rosette) casts jointly with the nutrient sampling, as well as well as sea-ice collected from Bio ice-core types on Ice Station, for analysis of nitrate d15N, d18O isotopic composition. Results have been interpreted in the light of prevailing nitrate-nutrient concentrations (Belgian team) and N-uptake regimes for the Ice Stations (new vs. regenerated production and nitrification; see Silicon, Carbon and Nitrogen in-situ incubation Metadata file). Methodology and sampling strategy: Samples for isotopic composition of nitrate were collected from the CTD rosette, TMR and Bio ice-core jointly with the nutrient sampling. Sea-ice sampling: sampling strategy follows ice stations deployment via Bio ice-core type. Most of the time we worked close to / directly on the Trace Metal site following precautions concerning TM sampling (clean suits etc.). When we worked close to the TM site, precautions were not such important because we don't need the same drastic precautions for our own sampling. We work together because we want to propose a set of data which helps to characterize the system of functioning in close relation with TM availability (for that, sampling location have to be as close as possible). All samples were filtered on 0.2 microns acrodiscs and kept at -20 degrees C till analysis in the home-based laboratory. We applied the denitrifier method elaborated by Sigman et al. (2001) and Casciotti et al. (2002). This method is based on the isotopic analysis of delta 15N and delta 18O of nitrous oxide (N2O) generated from nitrate by denitrifying bacteria lacking N2O-reductase activity. As a prerequisite the nitrate concentrations need to be known (nutrients analysis in the home lab.) as this sets sample amount provided to the denitrifier community. Briefly, sample nitrate is reduced by a strain of denitrifying bacteria (Pseudomonas aureofaciens) which transform nitrate into N2O, but lack the enzyme to produce N2. N2O is then analysed for N, O isotopic composition by IRMS (Delta V, Thermo) after elimination of CO2, volatile organic carbon and further cryogenic focusing of N2O (Mangion, 2011). Casciotti K.L., D.M.Sigman, M.G. Hastings, J.K. Bohlke and A. Hilkert, 2002. Measurement of the oxygen isotopic composition of nitrate in seawater and freshwater using the denitrifier method, Analytical Chemistry, 74 (19): 4905-4912. Mangion P., 2011. Biogeochemical consequences of sewage discharge on mangrove environments in East Africa, PhD Thesis, Vrije Universiteit Brussel, 208 pp. Sigman D.M., Casciotti K.L., Andreani M., Barford C., Galanter M. and J.K. Bohlke, 2001. A bacterial method for the nitrogen isotopic analysis of nitrate in seawater and freshwater, Analytical Chemistry, 73: 4145-4153.

  • Overview of the project and objectives: To investigate whether the Nitrogen - Silicon - Carbon biogeochemical system functions in the Antarctic Marginal Ice Zone and shows spatial variability possibly induced by varying availability of Fe and other parameters in the region. This toolbox is part of project 4051 - samples were taken (1) on the same sea-ice site or very close than the one used for Trace Metal sampling; (2) via Trace Metal Rosette TMR; (3) via Conductivity Temperature and Depth CTD Rosette. It is also part of project 4073 since some intercalibration studies were conducted in collaboration with the primary production team. Three main tools were used which can be either independently or intricately studied. For this reason the complete set of sampling done for this stable isotope toolbox is summarized in one excel file which is duplicated and attached to three child metadata records. Same reasoning for raw data acquired on boar and on field information. This parent metadata record has thus three child metadata records. Each of the child metadata files explain individually the different approaches which were treated together by the same team to resolve the main question of sea-ice biogeochemical system functioning via the use of stable isotope ratio tools. The details of each are in the respective metadata records. The data are attached to this metadata record. METADATA FILES are: - 13C, 15N, 30Si in-situ incubation experiments during SIPEX 2 - Nitrogen and oxygen isotopic composition of nitrate during SIPEX 2 - Delta13C signal of brassicasterol and cholesterol in the Antarctic Sea-ice / Is there particulate barium in sea-ice?

  • Data show results of carbon and nitrogen stable isotopes in muscle tissue of Trematomus bernacchii collected at 5 sites adjacent to Casey Station. Sites are contaminated Brown Bay, near Wilkes Station, Shannon Bay and reference O'Brien Bay and Sparkes Bay. Approximately 1cm3 of muscle tissue from the left side of each fish was taken for stable isotopes analysis.

  • Krill, salps and pteropods were collected with an RMT8 net during the K-Axis cruise. Specimens were removed from the samples, measured and frozen at -20C until ready for analysis in Hobart. Individuals of known species were dried at -60C, ground to a fine powder, encapsulated into tin cups and analysed with an ICP-MS in the Central Science Laboratories, University of Tasmania. Samples were analysed for delta15N and delta13C. The salp was the common Southern Ocean species Salpa thompsoni and the krill were Euphausia superba, E. triacantha, E. frigida and Thysanoessa macrura. A small number (2) of the siphonphore Diphyes antarctica were also analysed. Pteropods analysed included both shelled (thecosomes) and naked (gymnosomes) pteropods. Columns E-O in the Pteropods worksheet in the spreadsheet are expressed as ratios.

  • Oceanographic measurements were collected aboard Aurora Australis cruise au1121, voyage "Marine Science" (i.e. voyage 2.1) 2010/2011, from 4th January to 6th February 2011. The cruise commenced with a full north to south occupation of the CLIVAR/WOCE meridional repeat section SR3, followed by work around the Antarctic continental margin in the region of the Adelie Depression and the former Mertz Glacier ice tongue. A total of 149 CTD vertical profile stations were taken on the cruise, most to within 15 metres of the bottom. Over 2000 Niskin bottle water samples were collected for the measurement of salinity, dissolved oxygen, nutrients (phosphate, nitrate+nitrite and silicate), oxygen-18, dissolved inorganic carbon (i.e. TCO2), alkalinity, pH, helium, tritium, and biological parameters, using a 24 bottle rosette sampler. Upper water column current profile data were collected by a ship mounted ADCP. Meteorological and water property data were collected by the array of ship's underway sensors. An array of 3 bottom mounted ADCP moorings were deployed near the Adelie Depression, for recovery in the 2012/13 season. Underway data were also collected on this voyage, and are linked to this metadata record at the provided URL. A detailed readme is available as part of the download. Finally, ADCP (Acoustic Doppler Current Profiler) data are also linked, and are in Matlab format.

  • Zooplankton were collected during the winter-spring transition during two cruises of the Aurora Australis: SIPEX in 2007 and SIPEX II in 2012. As part of the collections sea ice cores were collected to describe the ice habitat during the period of zooplankton collections. Ice cores were taken with a 20 cm diameter SIPRE corer and sectioned in the field with an ice core. Particulate organic matter (POM) and animals from the zooplankton (water column) and the sea ice cover (meiofauna) were processed for stable isotopes - delta 13 Carbon and delta 15 Nitrogen.

  • Sediment cores were collected from the East Antarctic margin, aboard the Australian Marine National Facility R/V Investigator from January 14th to March 5th 2017 (IN2017_V01; (Armand et al., 2018). This marine geoscience expedition, named the “Sabrina Sea Floor Survey”, focused notably on studying the interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles. The cores were collected using a multi-corer (MC) and a Kasten corer (KC). The MC were sliced every centimetre, wrapped up in plastic bags, and stored in the fridge. The KC was sub-sampled using a u-channel; and sliced every centimetre once back the home laboratory (IMAS, UTAS, Hobart, Australia). This dataset presents stable isotopes measured in total and fumigated (i.e. organic) sediment samples collected during the IN2017_V01 voyage. The data include the sampling date (day/month/year), the latitude and longitude (in decimal degrees), the seafloor depth (in meter), the sediment core ID, the sediment depth (in cm), the elemental concentration (in %) and the stable isotope (13C, 15N and 34S) compositions reported as delta values (in ‰). This dataset presents stable isotopes measured in fumigated (i.e. organic) sediment samples collected during the IN2017_V01 voyage. The data include the sampling date (day/month/year), the latitude and longitude (in decimal degrees), the seafloor depth (in meter), the sediment core ID, the sediment depth (in cm), the elemental concentration (in %) and the stable isotope (13C and 15N) compositions reported as delta values (in ‰). Sediment samples were dried in an oven at 40°C and ground using a pestle and a mortar. Thirty mg of sediment was weighed into a tin cup for elemental and stable isotope analysis at the Central Science Laboratory (CSL), University of Tasmania. Total carbon (C), nitrogen (N) and sulfur (S) content was analysed by elemental analyser using flash combustion (Elementar, vario PyroCube, Germany). The stable isotopes 13C, 15N and 34S were analysed by isotope Ratio Mass Spectrometry (IRMS, Isoprime100). A duplicate sample of 35 mg was weighed into a silver cup for organic C measurement. Fifty µL of MQW was added into this cup and the samples were fumigated with concentrated HCl within a desiccator for 24h (Komada et al., 2008) to remove inorganic C. Samples were finally dried in an oven at 60°C and analysed. Isotopic results are reported as delta values (δX; where X = 13C,15N or 34S): δX =(R_sample / R_standard -1)×1000 ‰ where R is the ratio 13C/12C, 15N/14N or 34S/32S respectively. The δ13C value is reported respective to the PDB (Pee Dee Belemnite) standard; the δ15N is reported with reference to air; and δ34S is reported respective to the CTD (Canyon Diablo troilite) standard. References - Armand, L. K., O’Brien, P. E., Armbrecht, L., Baker, H., Caburlotto, A., Connell, T., … Young, A. (2018). Interactions of the Totten Glacier with the Southern Ocean through multiple glacial cycles (IN2017-V01): Post-survey report. ANU Research Publications. - Komada, T., Anderson, M. R., and Dorfmeier, C. L. (2008). Carbonate removal from coastal sediments for the determination of organic carbon and its isotopic signatures, δ 13 C and Δ 14 C: comparison of fumigation and direct acidification by hydrochloric acid . Limnology and Oceanography: Methods, 6(6), 254–262.