Euthecosomata pteropods were analysed in core sediments collected in the framework of the 2016 EUROFLEETS2 SEMSEEP cruise, offshore of Israel, in the eastern Mediterranean Sea. The investigated cores were retrieved in a deep-sea coral area at 690 m depth, an actively methane-seeping pockmark area at 1038 m depth, and a deep-sea channel area at 1310 m water depth. We identified and documented the pteropod species belonging to the families Heliconoididae, Limacinidae, Creseidae, Cavoliniidae, Cliidae, and Hyalocylidae and to some heteropods. Our study highlights the importance of investigating pteropods in the size fractions > 63 μm instead of the > 125 μm only. In particular, neglecting the small size fraction may result in a remarkable (up to 50 %-60 %) underestimation of the relative abundance of the epipelagic species Creseis acicula and Creseis conica and the mesopelagic species Heliconoides inflatus. This may significantly affect palaeoenvironmental reconstructions. The observed presence of tropical species supports the suggestion that the eastern Mediterranean is a refugium for these species. This study provides a basic benchmark for the late Holocene evolution of pteropod and heteropod distribution over 5800-5300 cal BP across the base of the south-eastern Levantine margin.
Bibliographical noteFunding Information:
The authors thank the scientific and technical crew of the R/V Aegaeo for providing technical support during the cruise. The EUROFLEETS2 SEMSEEP cruise was funded by the European Union FP7 Programme under grant agreement no. 312762. Funding for shore-based investigations, which made this research possible, was provided by the Swiss National Science Foundation (SNSF), grant ref. 200021_175587. We warmly thank Christoph Neururer, who helped during SEM operations. We thank Sandra Borderie, from the University of Fribourg, for her help in the use of the free software package GMT (Generic Mapping Tools: Wessel and Smith, 1991). Karin Wyss and Negar Haghipour at ETH Zurich are thanked for help with sample preparation and the AMS analysis. We acknowledge the Norwegian Research Council through the project AKMA, Advancing Knowledge of Methane in the Arctic (project number 287869), for funding isotope analyses.
This research has been supported by the Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (grant no. 200021_175587), the Norges Forskningsråd (grant no. 287869), and the European Commission, Seventh Framework Programme (EUROFLEETS2 (grant no. 312762)).
© 2023 Valentina Beccari et al.
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