A High-Resolution Coral-Based Δ14C Record of Surface Water Processes in the Western Mediterranean Sea

• Published in: Radiocarbon
• Main Authors: Tisnerat-Laborde, N., Montagna, Paolo, Mcculloch, Malcolm, Siani, G., Silenzi, Sergio, Frank, Norbert
• Other Authors: Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Géochrononologie Traceurs Archéométrie (GEOTRAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Istituto di Science Marine (ISMAR ), National Research Council of Italy, Research School of Earth Sciences ANU, Canberra (RSES), ANU College of Science Canberra, Australian National University (ANU)-Australian National University (ANU), Géosciences Paris Sud (GEOPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: Panoply; [SDU]Sciences of the Universe [physics]; North Atlantic
• Online Access: https://hal.science/hal-01501859; https://hal.science/hal-01501859/document; https://hal.science/hal-01501859/file/tisnerat_high_1.pdf; https://doi.org/10.1017/S0033822200048530

International audience The first high-resolution time series of pre- and post-bomb radiocarbon measurements is reported for surface waters in the western Mediterranean Sea. The Δ14C record was obtained from the aragonite skeleton of Cladocora caespitosa using a 50-yr-old corallite collected in the Ligurian Sea in 1998. Laser-ablation ICP measurements of trace elements (Li/Mg and Sr/Ca) show a strong seasonal variability, enabling the chronology of the Δ14C record to be determined at annual timescales. The mean Δ14C of pre-bomb surface water is –56 ± 3‰, corresponding to a reservoir age of 262 ± 29 yr. The post-bomb maximum occurs in 1972 with a Δ14C value of 90‰, significantly lower than the peak of 150‰ observed in the North Atlantic. The dilution of the peak-amplitude of Δ14C in western Mediterranean surface waters is attributed to mixing of North Atlantic Central Water inflow with relatively depleted underlying Intermediate Mediterranean and Levantine Intermediate waters. Intensification of this mixing is observed in 1963–1964, consistent with the change in atmospheric circulation from a positive to negative NAO phase (1960–1967). The post-peak Δ14C variability is relatively limited, reflecting mainly local vertical mixing forced by wind stress.