Dataset: B. gymnorhiza isotopes
Deployment: Ongael_2013-09

All methodology was described in Ladd & Sachs, GCA, 2017, doi: 10.1016/j.gca.2017.01.046

Surface water and precipitation δ2H and δ18O values were measured with a Picarro Cavity Ring Down Spectroscopy (CRDS) L2130i Water Isotope Analyzer at the University of Washington measured. Three laboratory standards of known isotopic composition were analyzed after every six samples and were used to normalize results to the Vienna Standard Mean Ocean Water (VSMOW) scale. All samples and standards were injected six times, and the first three measurements were discarded in order to avoid any memory effects from the previous analysis. Leaf and xylem water samples were analyzed by a Thermal Conversion Elemental Analyzer (TC/EA) coupled to a Delta V Isotope Ratio Mass Spectrometer (IRMS; ThermoFisher Scientific, Waltham, MA) at the University of Basel, Switzerland. Each sample and standard was injected six times in sequence. In order to avoid any memory effects from the previous analysis, the first three injections of each sample were discarded.

The δ2H values of individual lipids were measured by GC-IRMS on a Thermo DELTA V PLUS system (ThermoFisher Scientific, Waltham, MA, USA). The GC (Trace Ultra, ThermoFisher Scientific) was equipped with a split-splitless injector operated in splitless mode at 320 deg C, a TRIPLUS autosampler (ThermoFisher Scientific), and a VF-17ms capillary column (60 m X 0.25 mm X 0.25 um, Agilent). For lupeol analyses, the GC was heated from 120 deg C to 260 deg C at 20 deg C/min, then at 1 deg C/min to 300 deg C, at 20 deg C/min to 325 deg C and then held at 325 deg C for 20 min. For n-alkane analyses, the GC was heated from 120 deg C to 250 deg C at 20 deg C/min, then at 6 deg C/min to 325 deg C and then held at 325 deg C for 12 min. Helium was used as the carrier gas at a constant flow of 1.1 mL/min. Compounds were pyrolyzed in a ceramic reactor at 1400 deg C. 1 uL of sample was injected along with 0.5 uL of a mix of n-alkanes of known isotopic composition (A. Schimmelmann, Indiana University, Bloomington, Indiana). For lupeol analyses, this mix included nC26-, nC28-, nC32-, nC34- and nC41-alkanes. For n-alkane analyses, the co-injection standards were nC21 and nC23. At the beginning and the end of the sequence, as well as after every 4-6 sample injections, a mixture of additional n-alkane standards of known isotopic composition was analyzed with the co-injection standards, in place of a sample. For isoprenoid sequences, this external standard was nC38-alkane. For n-alkane sequences, nC28-, nC32- and nC34-alkanes were used as external standards.

BCO-DMO Data Processing Notes:

- reformatted column names to comply with BCO-DMO standards.
- converted lat/lons from degree minute format to decimal degrees.
- converted date format from YYMMDD to YYYY/MM/DD