ALBERT

Description: Lipid and environmental data were compiled from previously published datasets of modern samples that used the most recent chromatographic methods that separate 5- and 6-methyl isomers. The compiled dataset (n = 3129) consisted of bone (n = 202), groundwater (n = 7), lake water meso/microcosm (n = 36), lake surface sediment (n = 343), lake water SPM (n = 228, including sediment traps (n = 115) and water filtrates (n = 113)), low DO lake water SPM (n = 138, including sediment traps (n = 29) and water filtrates (n = 109)), authigenic carbonates from a marine methane cold seep (n = 13), marine surface sediment (n = 325, including deep ocean trench sediments (n = 31)), marine SPM (water filtrates, n = 25), peat (n = 473), riverine surface sediments (n = 71) and SPM (water filtrates, n = 85), and soil (n = 1183, including permafrost active layer (n = 17)). Data from other sample media, including hot springs, speleothems, and hydrothermal vents, could not be included as these studies did not separate the 5- and 6-methyl isomers. Fractional abundances (FAs) were calculated according to Raberg et al., (2021). We compiled the brGDGT FAs and, to the best of our ability, associated temperature and pH values from previously published datasets. We selected temperature parameters that were widely supported in the literature when possible. Where a consensus had yet to be reached (e.g., marine sediments), we selected standardizable and accessible parameters (e.g., sea surface temperatures). These selections are not intended to opine on these areas of research, only to allow for broad comparison with other sample types in this study.