Cold-Water Coral Mound Archive Provides Unique Insights Into Intermediate Water Mass Dynamics in the Alboran Sea During the Last Deglaciation

• Main Authors: Fentimen, Robin, Feenstra, Eline, Rüggeberg, Andres, Vennemann, Torsten, Hajdas, Irka, Adatte, Thierry, van Rooij, David, Foubert, Anneleen
• Other Authors: Laboratoire de Planétologie et Géosciences UMR_C 6112 (LPG), Le Mans Université (UM)-Université d'Angers (UA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Nantes université - UFR des Sciences et des Techniques (Nantes univ - UFR ST), Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ)-Nantes Université - pôle Sciences et technologie, Nantes Université (Nantes Univ)-Nantes Université (Nantes Univ), Department of Geosciences - Earth Sciences Fribourg, Université de Fribourg = University of Fribourg (UNIFR), Université de Lausanne = University of Lausanne (UNIL), Departement Physik ETH Zürich (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Universiteit Gent = Ghent University (UGENT), Swiss National Science Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: benthic foraminifera stable isotopes grain size Mediterranean paleoenvironment Bølling-Allerød; benthic foraminifera; stable isotopes; grain size; Mediterranean; paleoenvironment; Bølling-Allerød; [SDE.MCG]Environmental Sciences/Global Changes; Greenland
• Online Access: https://univ-angers.hal.science/hal-04278641; https://univ-angers.hal.science/hal-04278641/document; https://univ-angers.hal.science/hal-04278641/file/fmars-07-00354.pdf; https://doi.org/10.3389/fmars.2020.00354

The Alboran Sea is widely recognized to host numerous cold-water coral ecosystems,including the East Melilla Coral Province. Yet, their development through timeand response to climatic variability has still to be fully understood. Based ona combined investigation of benthic foraminiferal assemblages, foraminiferal stableisotope compositions, grain size analysis, sediment geochemistry, and macrofaunalquantification, this study identifies key events and processes having governed coldwatercoral development at the East Melilla Coral Province between Greenland Stadial2.1 and the Early Holocene. The transition from Greenland Stadial 2.1 to GreenlandInterstadial 1 is associated to a decline of bryozoan communities and their replacementby cold-water corals, together with changes in benthic foraminiferal assemblages and adecrease in the sediment mean grain size. These results suggest that a rapid decreasein bottom currents and the establishment of dysoxic and mesotrophic conditions atthe seafloor, possibly associated to enhanced fluvial input, resulted in the declineof bryozoans as the dominant suspension feeding organisms and their replacementby a thriving cold-water coral community. This transition from a bryozoan to a coraldominated environment is concomitant with the beginning of the African Humid Period,confirming that increasing fluvial input could have been a main factor triggering theestablishment of cold-water corals in the East Melilla Coral Province during GreenlandInterstadial 1. A change in benthic foraminiferal communities and an increase in thesediment mean grain size mark the passage from the Early to Late Greenland Interstadial1. The current velocity of intermediate water masses is suggested to have increasedduring the Early to Late Greenland Interstadial 1, whilst simultaneously fluvial input wouldhave reduced. Such changes suggest that the climate became more arid during thesecond phase of Greenland Interstadial 1.