TY - JOUR AU - Chen, Xin AU - Liu, Xiaodong AU - Lin, Da-Cheng AU - Wang, Jianjun AU - Chen, Liqi AU - Yu, Pai-Sen AU - Wang, Linmiao AU - Xiong, Zhifang AU - Chen, Min-Te PY - 2021 DA - 2021/04/06 TI - A potential suite of climate markers of long-chain n-alkanes and alkenones preserved in the top sediments from the Pacific sector of the Southern Ocean JO - Progress in Earth and Planetary Science SP - 23 VL - 8 IS - 1 AB - Investigating organic compounds in marine sediments can potentially unlock a wealth of new information in these climate archives. Here, we present pilot study results of organic geochemical features of long-chain n-alkanes and alkenones and individual carbon isotope ratios of long-chain n-alkanes from a newly collected, approximately 8 m long, located in the far reaches of the Pacific sector of the Southern Ocean. We analyzed a suite of organic compounds in the core. The results show abundant long-chain n-alkanes (C29–C35) with predominant odd-over-even carbon preference, suggesting an origin of terrestrial higher plant waxes via long-range transport of dust, possibly from Australia and New Zealand. The δ13C values of the C31 n-alkane range from −29.4 to −24.8‰, in which the higher δ13C values suggest more contributions from C4 plant waxes. In the analysis, we found that the mid-chain n-alkanes (C23–C25) have a small odd-over-even carbon preference, indicating that they were derived from marine non-diatom pelagic phytoplankton and microalgae and terrestrial sources. Furthermore, the C26 and C28 with lower δ13C values (~−34‰) indicate an origin from marine chemoautotrophic bacteria. We found that the abundances of tetra-unsaturated alkenones (C37:4) in this Southern Ocean sediment core ranges from 11 to 37%, perhaps a marker of low sea surface temperature (SST). The results of this study strongly indicate that the δ13C values of long-chain n-alkanes and $$ {U}_{37}^{\mathrm{k}} $$index are potentially useful to reconstruct the detailed history of C3/C4 plants and SST change in the higher latitudes of the Southern Ocean. SN - 2197-4284 UR - https://doi.org/10.1186/s40645-021-00416-9 DO - 10.1186/s40645-021-00416-9 ID - Chen2021 ER -