Age model, sea surface temperature and marine calcifying plankton changes at two sites in the western Mediterranean Sea for the Common Era

Three high resolution multicore records from two western Mediterranean Sea regions (Alboran and Balearic basins) have been analyzed for sea surface temperature (SST), coccolithophore and planktic foraminiferal abundance changes. Age-depth models at both sites were developed by a combination of 210Pb and 14C dating techniques, describing high sedimentation rates at both study sites, covering the time interval from the Medieval climate anomaly to present. Alkenone derived SST of core MedSeA-S3-c1 and MedSeA-S23-c3 are in good agreement with other results, tracing temperature changes through the Common Era (CE) and show a clear warming emergence at about 1850 CE. Analysis of relative abundance of calcareous nannoplankton assemblages (coccolithophores) was done on core MedSeA-S3-c1 (150 µm. Both cores show opposite abundance fluctuations of planktic foraminiferal species (Globigerina bulloides, Globorotalia inflata and Globorotalia truncatulinoides). The relative abundance changes of Globorotalia truncatulinoides plus Globorotalia inflata describe the intensity of deep winter mixing in the Balearic basin. In the Alboran Sea, Globigerina bulloides and Globorotalia inflata instead respond to local upwelling dynamics. Our data suggests that planktic foraminiferal abundance and species changes in the western Mediterranean Sea is already affected by accelerated anthropogenic warming, overprinting natural cycles in this region.