Stable-carbon isotope compositions for crenarchaeol, bacteriohopanetetrol I (BHT-I), and bacteriohopanetetrol II (BHT-II) for ODP cores at sites 964 and 967. All biomarkers were measured using a Thermo Scientific Delta V isotope ratio mass spectrometer at least in triplicate. For BHT-I and BHT-II, compounds were isolated using high-performance preparative liquid chromatography and individually analyzed by high-temperature gas-chromatography-IRMS following Hemingway et al. (2018). Crenarchaeol was isolated using high-pressure preparative chromatography and analyzed using a spooling-wire microcombustion interface on a Thermo Scientific Delta V isotope ratio mass spectrometer at least in quintuplicate following Polik et al. (2018).This work was supported by the Gordon and Betty Moore Foundation.

Carbon stable isotopic composition of crenarchaeol (δ13C Cren.), bacteriohopanetetrol I (δ13C BHT-I), and bacteriohopanetetrol II (δ13C BHT-II). F2/F1 size ratio describes the crenarchaeol-carbon to background-carbon ratio as an indicator of potential bias δ13C Cren by high background. Values above 2 indicate unbiased samples (Polik et al., 2018). Differences between δ13C Cren, δ13C BHT-I, and δ13C BHT-II are given.