Marine and terrestrial biomarkers analyses have been carried out on sediments from Ocean Drilling Program Site 975 in the Algero-Balearic basin (38°53.8′ N, 4°30.6′ E), through late marine isotope stage (MIS) 20-19 (from 800 to 756 thousand years ago). Marine and terrestrial biomarkers have been processed at the Instituto Português do Mar e da Atmosfera (Portugal). The patterns of C37 alkenone concentration and NAR provided reliable information on past paleoproductivity changes. The Alkanol Preservation Index (API) obtained by the relative proportion of n-hexacosan-1-ol (C26OH) to the sum of C26OH plus n-nonacosane (C29) [API = C26OH/(C26OH + C29)], was used as a proxy of sea bottom ventilation in the basin. Sea surface temperature (SST) was estimated calculating the alkenone Uk'37 index that is based on the di- and tri-unsaturated alkenone ratio [(C37:2)/(C37:2 + C37:3)] and converted into temperature values using the global core top calibration of annual SST [Uk'37 = (0.033*SST) + 0.044], with a methodology uncertainty of ±0.5 ◦C. Tetra-unsaturated compound (C37:4) was considered as an indicator of lower temperature and low salinity waters and linked to polar and subpolar water influx into the Western Mediterranean.

This dataset was funded by a Geoscience PhD scholarship from University of Bari, Italy.