Methods are as per \"Southward Shift of the Pacific ITCZ During the Holocene\" in Paleoceanography and Paleoclimatology, volume 33, pages 1383-1395 (Sachs et al. 2018).
\nSediment core PTLN\u2010PC1 was collected September 2013 in sequential 1m sections using a 5cm\u2010diameter Colinvaux\u2010Vohnout Livingstone\u2010type rod\u2010operated piston corer (Geocore, Columbus, Ohio). Each section was sealed in the field and refrigerated at 4 \u00b0C until core splitting and subsampling.
\nSample ages were linearly interpolated from calibrated 14C dates (see dataset \"T Lake PC1 Chronology\") using the Clam 2.2 (Blaauw, 2010) software package.
\nSediment subsamples were transferred to combusted glass vials, frozen, then freeze dried. Lipids were extracted with 10% methanol in dichloromethane on an accelerated solvent extractor (ASE 200; Dionex) at 100\u00b0C and 1500 psi with three 5\u2010min static cycles. Lipid extracts were saponified using 2:1 1N KOH in methanol:water at 70\u00b0C overnight. Saponified extracts were acidified to pH ~1 with HCl, neutral lipids extracted from the water/methanol phase with hexane, and the hexane extracts washed with water. Lipid extracts were acetylated at 70\u00b0C for 30 min in a mixture of 20 \u03bcl acetic anhydride of known isotopic composition and 20 \u03bcl pyridine. Sterol acetates were then isolated via preparative high\u2010performance liquid chromatography as per the methods in Nelson and Sachs (2013, 2014). Extracts were taken up in 25 \u03bcl of 2:1 dichloromethane:methanol and the complete volume injected onto an Agilent 1100 high\u2010performance liquid chromatography system equipped with a Zorbax Eclipse XDB C18 column; after an initial elution of polar compounds in 5:95 methanol:acetonitrile, sterol acetates were eluted with an isocratic mobile phase of 5:10:85 methanol:ethyl acetate:acetonitrile. Aliquots (5%) of each sample were injected on an Agilent 6890N GC with flame ionization detector and PTV inlet, equipped with an Agilent VF\u201017 ms column (60 m \u00d7 0.32 mm \u00d7 0.25 \u03bcm), in splitless mode at 300\u00b0C using helium carrier gas at 1.5 ml/min. The initial oven temperature was 110\u00b0C, followed by a ramp to 320\u00b0C at 5\u00b0C/min, and was then held for 20 min. Detector response was determined via an \u03b1\u2010cholestane internal standard. Dinosterol fluxes were calculated from the product of dinosterol concentration per gram dry weight of sediment, the linear sediment accumulation rate, and the dry bulk density of sediment. Uncertainty in dinosterol fluxes is conservatively assumed to be 25%.
\nHydrogen isotopes of dinosterol were measured via a modification of the procedures outlined in Nelson and Sachs (2013). Gas chromatography was conducted using a Thermo Trace GC Ultra equipped with a GC\u2010TC interface. Samples were injected into the 330\u00b0C inlet in splitless mode, with a 1.1 ml/min helium carrier flow through a VF\u201017 ms column (60 m \u00d7 0.25 mm \u00d7 0.25 \u03bcm). The oven temperature was held at 120\u00b0C for the 2\u2010min splitless time, increased to 260 \u00b0C at 20 \u00b0C/min, increased to 325\u00b0C at 1\u00b0C/min, and held for 10 min. The pyrolysis interface was operated at 1400\u00b0C, and the sample hydrogen admitted to a Thermo Delta V Plus isotope ratio mass spectrometer via open split.
\nIsotope measurements are given as \u03b4\u00b2>H values relative to Vienna Standard Mean Ocean Water and calibrated via external isotope standards (Arndt Schimmelmann, Indiana University). Secondary corrections were determined based on time\u2010in\u2010sequence, retention time, and peak area, as necessary, on a sequence\u2010by\u2010sequence basis. Each sample analyzed at least three times. \u03b4\u00b2H values were corrected for added acetate hydrogen (\u2212124.4\u2030 \u00b1 8.1) via mass balance. Uncertainty is given as the standard deviation of these replicate analyses and uncertainty in the value of the known acetate, propagated through the mass balance calculation.
These data are published in Table 2 of Sachs et al., 2018 (doi:\u00a010.1029/2018PA003469)
BCO-DMO Processing:\u00a0modified parameter names (changed \"2H_dino\" to \"dino_2H\" because column names cannot start with\u00a0numbers)