U37K' is unaffected by IODP repository conditions

The alkenone palaeothermometer is one of the principal methods by which past sea surface temperatures are reconstructed on Cenozoic timescales. Alkenone temperatures, produced from the U K ’ 37 ratio of C 37:2 and C 37:3 alkenones, have been generated in hundreds of studies, many using ocean sediment recovered by projects such as the International Ocean Discovery Program (IODP) and its precursors. Large repositories of sediment drilled from 1969 to the present day are available for analysis, but as organic molecules, alkenones are potentially vulnerable to degradation, and the impact of time spent stored in IODP repositories is an unstudied source of alterations to the index. Here, we re-analyse U K ’ 37 from DSDP 594 and ODP Site 982: cores that had previously produced high-resolution temperature records published 15 and 5 years ago. We show that the time spent in a repository had no effect on U K ’ 37 outside of analytical uncertainty. We conclude that repository conditions do not affect U K ’ 37 , and alkenone palaeotemperatures generated from archived core material are likely to remain accurate.