Cladoceran assemblages of the Last Interglacial obtained from permafrost lacustrine deposits exposed at the Laptev Sea coast

• Main Authors: Frolova, Larissa, Schirrmeister, Lutz, Nigmatullin, N, Wetterich, Sebastian
• Format: Conference Object
• Language: unknown
• Published: 2024
• Subjects: Arctic; laptev; Laptev Sea; permafrost; Subarctic; Tundra; Yakutia; Siberia
• Online Access: https://epic.awi.de/id/eprint/58687/; https://epic.awi.de/id/eprint/58687/1/EGU24-20253-print.pdf; https://hdl.handle.net/10013/epic.821a4074-f535-41bd-b4f7-82d8985510c5

The cladoceran assemblages of the lacustrine deposits of the Krest-Yuryakh sequence (Marine Isotope Stage 5e, MIS5e; Last Interglacial, LIG) exposed at the southern coast of Bol’shoy Lyakhovsky Island and the Oyogos Yar mainland coast along the Dmitry Laptev Strait (Yakutia, Siberia, Russia) were investigated. Field studies on both sides of the Laptev Strait were conducted in 2002, 2007, and 2014. The vegetation of the study area is currently represented by Arctic tundra. The mean air temperature of the warmest month of the year (MTWA) is 3.5 °C for the studied sites on Bol’shoy Lyakhovsky Island and 6.9 °C for Oyogos Yar (https://www.worldclim.org; Fick and Hijmans, 2017). Age information of the Krest-Yuryakh lacustrine deposits is based on infrared-stimulated luminescence (IRSL) (Schirrmeister et al., submitted). Cladocera were studied in profile L7-11 on Bol’shoy Lyakhovsky Island and in profiles Oya-3-11, Oy7-01, Oy7-08, Oya 5-1 on Oyogos Yar.? The studied fossil cladocera remains of Krest-Yuryakh deposits are exceptionally well preserved. The overall cladocera record comprises 13 taxa. The most common species are Chydorus cf. sphaericus, Bosmina sp. and Daphnia pulex gr. The cladoceran assemblages are dominated by littoral shallow-water taxa, such as Chydorus cf. sphaericus, Alona guttata / Coronatella rectangula. However, profile L7-11 on Bol’shoy Lyakhovsky had very low concentrations of specimens of which Chydorus cf. sphaericus is the most common species. The cladoceran records on Oyogos Yar are more diverse and had much higher concentrations than those on Bol’shoy Lyakhovsky. Most of the cladoceran remains on Oyogos Yar belong to littoral phytophilous species, associated with macrophytes. In the cladoceran communities of Oyogos Yar, along with cold-water taxa, also more thermophilic taxa were found. In particular, the findings of remains of the species L. leidigi indicate much warmer conditions in the past than today. According to Flößner (2000), this species is absent nowadays in the arctic-subarctic ...