Stable isotopes concentrations measured in sediment samples collected during the IN2017-V01 voyage of the RV Investigator

Brief description

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.

Lineage

Progress Code: completed

Statement: An empty tin cup was run at the beginning of the analysis and the obtained blank was then subtracted from all subsequent samples. Sulfanilamide EA standards containing a known amount of carbon and nitrogen were run every 6th sample and used for instrument drift and elemental quantification. This method provides quantitative data on element content in the samples, generally achieving a precision of 0.1% for C and N concentrations.

Notes

Purpose
These data were collected to determine the stable isotope composition and organic carbon concentration of marine sediment.