Cold-water corals (CWCs) are widely scattered in the southern Alboran Sea (westernmost Mediterranean), specifically in the so-called East and West Melilla CWC mound provinces (EMCP, WMCP). In this study, we present environmental changes in West Melilla from the sediment core MD13-3451 (370 m water depth) across the last deglaciation (~14 kyr BP), followed by an assessment of the WMCP temporal evolution. The reconstructed palaeoceanographic changes allows the identification of diverse circulation patterns, which potentially influenced the local environment framework and thus CWCs occurrence patterns. The performed analyses include sedimentary characteristics (grain-size records), geochemical measurements in foraminifera coating (U/Mn ratio) and calcite (stable isotopes, Mg/Ca-derived Deep Water Temperatures; DWTs), and the assessment of benthic species assemblages (relative abundance of Globobulimina affinis communities). Furthermore, seawater δ18O (δ18Osw) and seawater δ18O corrected for the ice volume signal (δ18Ow-ivc) have been estimated via paired analyses of Mg/Ca and δ18Ocarbonate. Our findings suggest: i) Pulses of relatively high DWTs, moderate to strong bottom water hydrodynamics, and well-oxygenated environment favored CWCs booming during the Earliest Holocene (EH), although these factors individually are here not considered determinant in their formation. ii) A rapid freshening of the waters occurred during the EH at our core site, indicating major oceanographic changes. These results, when combined with available records from neighbor sites, reveal that such flourishing stage is closely coupled to a re-organization of the Alboran Sea water column structure. More precisely, to the emergence of a newly formed water mass probably originated in the Gulf of Lion (northwestern WM), which should replace the older Levantine Intermediate Water (LIW) and promotes the reactivation of CWCs. Overall, our results highlight the crucial role of the Mediterranean circulation in shaping the southern Alboran Sea mound formation, and also emphasize the importance of integrating a wide range of environmental variables when investigating the complex set of CWCs controls.
Environmental conditions controlling Cold-water corals occurrence in western Melilla (western Mediterranean) since the last deglaciation’ / Selvaggi, Mar; de la Fuente, Maria; Català, Albert; Pérez-Asensio, José N.; Lo Iacono, Claudio; Haghipour, Negar; Trias-Navarro, Sergi; Corbera, Guillem; DI BELLA, Letizia; Cacho, Isabel. - (2024), pp. 1-1. (Intervento presentato al convegno EGU 2024 tenutosi a Vienna).
Environmental conditions controlling Cold-water corals occurrence in western Melilla (western Mediterranean) since the last deglaciation’
Mar Selvaggi;Letizia di Bella;
2024
Abstract
Cold-water corals (CWCs) are widely scattered in the southern Alboran Sea (westernmost Mediterranean), specifically in the so-called East and West Melilla CWC mound provinces (EMCP, WMCP). In this study, we present environmental changes in West Melilla from the sediment core MD13-3451 (370 m water depth) across the last deglaciation (~14 kyr BP), followed by an assessment of the WMCP temporal evolution. The reconstructed palaeoceanographic changes allows the identification of diverse circulation patterns, which potentially influenced the local environment framework and thus CWCs occurrence patterns. The performed analyses include sedimentary characteristics (grain-size records), geochemical measurements in foraminifera coating (U/Mn ratio) and calcite (stable isotopes, Mg/Ca-derived Deep Water Temperatures; DWTs), and the assessment of benthic species assemblages (relative abundance of Globobulimina affinis communities). Furthermore, seawater δ18O (δ18Osw) and seawater δ18O corrected for the ice volume signal (δ18Ow-ivc) have been estimated via paired analyses of Mg/Ca and δ18Ocarbonate. Our findings suggest: i) Pulses of relatively high DWTs, moderate to strong bottom water hydrodynamics, and well-oxygenated environment favored CWCs booming during the Earliest Holocene (EH), although these factors individually are here not considered determinant in their formation. ii) A rapid freshening of the waters occurred during the EH at our core site, indicating major oceanographic changes. These results, when combined with available records from neighbor sites, reveal that such flourishing stage is closely coupled to a re-organization of the Alboran Sea water column structure. More precisely, to the emergence of a newly formed water mass probably originated in the Gulf of Lion (northwestern WM), which should replace the older Levantine Intermediate Water (LIW) and promotes the reactivation of CWCs. Overall, our results highlight the crucial role of the Mediterranean circulation in shaping the southern Alboran Sea mound formation, and also emphasize the importance of integrating a wide range of environmental variables when investigating the complex set of CWCs controls.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.