For d18O diatom and diatom species abundance see Swaan (2010) dataset: doi:10.1594/PANGAEA.772032. Diatoms were extracted using existing techniques with analysed (75-150 µm) fraction dominated by two taxa; Coscinodiscus marginatus (Ehrenb.) and C. radiatus (Ehrenb.) (Swann, 2010, doi:10.1016/j.epsl.2010.06.035). d30Sidiatom was analysed using step-wise fluorination at the NERC Isotope Geosciences Laboratory, U.K., with silicon collected as SiF4. Measurements were made on a Finnigan MAT 253 stable isotope ratio mass spectrometre with values corrected using NIGL within-run laboratory diatom standard BFCmod against NBS28 (Leng and Sloane, 2008, doi:10.1002/jqs.1177).