Deglacial variations in provenance of terrigenous organic matter and temperature in the Northwest Pacific/western Bering Sea realm inferred from biomarkers

• Main Authors: Meyer, Vera, Hefter, Jens, Max, Lars, Schefuß, Enno, Tiedemann, Ralf, Mollenhauer, Gesine
• Format: Conference Object
• Language: unknown
• Published: 2015
• Subjects: Bering Sea; Climate change; Global warming; Greenland; Greenland ice core; Ice; ice core; Kamchatka; Kamchatka Peninsula; permafrost; Subarctic
• Online Access: https://epic.awi.de/id/eprint/41862/; https://hdl.handle.net/10013/epic.48684

During the last glacial termination atmospheric carbon dioxide (CO2atm) rose about 100 ppm and atmospheric radiocarbon activity (Δ14C) concurrently dropped by about ca. 400 ‰. Global warming likely triggered large-scale thawing of permafrost soils in the northern hemisphere resulting in release of 14C-depleted carbon which may have contributed to the changes in CO2atm and Δ14C1. However, the timing and duration of the thawing as well as regional differences regarding these points are poorly understood. In order to unravel the evolution of permafrost decomposition and its role within the glacial-interglacial climate change a profound understanding of the deglacial carbon-turnover and temperature development in subarctic and arctic regions are of great importance. Working with two sediment cores from the continental margin off Kamchatka Peninsula, western Bering Sea (WBS, site SO201-2-114KL) & Northwest Pacific (NW Pacific, site SO201-2-12KL) we establish Glacial to Holocene records in sea surface temperature (SST) and mean air temperature (MAT) using the TEXL86 (SST) and CBT/MBT (MAT) temperature proxies that are based on marine and terrigenous biomarkers (Glycerol dialkyl glycerol tetraethers). The hydrogen isotopic composition (δD) of plant-wax derived lipid biomarkers (long-chain n-alkanes and long-chain n-fatty acids) is another tool for reconstructing air temperature but can also provide information of the provenance of terrigenous organic matter (OM). The radiocarbon activity of the lipid biomarkers is applied to reconstruct changes in terrestrial residence times of terrigenous OM. Our records in SST and CBT/MBT-based MAT are interpreted as summer temperatures. From the Bølling/Allerød interstadial (B/A) to the present they show temperature fluctuations similar to Greenland ice core records including a warming at the onset of the B/A and a cooling during the Younger Dryas (YD) followed by a warming into the Preboreal (PB) suggesting an atmospheric coupling between N-Atlantic and N-Pacific, East ...