Organic matter composition of polygon-patterned tundra in the Thule area (NW Greenland)

This thesis on organic matter composition of polygon-patterned tundra in the Thule are in Northwestern Greenland is based on analysis of a permafrost core obtained during an expedition of the Danish NOW project in August 2015. In the ice-sheet marginal coastal area in NW Greenland, Holocene ice-wedge polygons developed under permafrost conditions. The ice-wedge growth in accumulating peats linked to the presence of local sea bird colonies is the topic of this thesis. It was found that in the study area there is a high presence of nitrogen within the soil as well as very high ice content, linking to the syngenetic freezing and permafrost aggradation. The samples obtained from the core were processed in the laboratory and analyzed for ice content, age of the core, carbon and nitrogen content, threshold of organic carbon and isotopic abundance ratios of total organic carbon and total nitrogen. Analytical results show a quite steady content of all of these features with some exceptions at different depths for each parameter. It was also found that there had to be a change in permafrost aggradation and peat accumulation approx. 3000 years BP (before present, meaning before 1950) as the accumulation rate drops at this point in time. The great impact of the bird colonies on this specific permafrost formation is reflected as the high nitrogen values indicate that the birds’ droppings were the original source of organic matter to decompose, allowing for vegetation growth and permafrost soil development. Temporary changes found in isotopic ratios within soil carbon may give a hint on bird colony evolution in the Thule area and the development towards the current state of the little auks’ colony momentary inhabiting the study area of GL-3

Organic Matter Characteristics in a Changing Permafrost Environment: Yukechi Alas Landscape, Central Yakutia

With alarmingly fast climate change on global scale, the origin of carbon emissions is becoming more important. Permafrost as one of the largest terrestrial natural storages is among the most relevant carbon sinks that might become a carbon source as air temperatures and snowfall are increasing. This study examines the Yukechi Alas area (N 61.76495° / E 130.46664°), a landscape in Central Yakutia, located on the Abalakh terrace in the Lena-Aldan interfluve). Two drilling cores from different ground types were taken. The comparison of the both cores used in this study also gives insights into the development of permafrost carbon storage. One is a Yedoma core, consisting of material accumulated and syngenetically frozen during the late Pleistocene. The second core was taken from an adjacent alas basin. Alas deposits in this area are altered Yedoma deposits thawed and subsided after lake formation. Both cores cover a timespan of approximately 50 000 years. The cores were analysed for ice content, total carbon and total nitrogen content, total organic carbon content, stable oxygen and hydrogen isotopes, stable carbon isotopes, mass specific magnetic susceptibility and grain size distribution, and were dated using radiocarbon measurements. The laboratory analyses revealed some interesting features that are quite uncommon for Yedoma deposits globally but have been found in Central Yakutia before. The most astonishing finding is the lack of carbon over several meters depth, found in both cores. While in the alas core this could hint on deep thawing during lake-covered stages and large talik formation, and hence decomposition, the same finding in the Yedoma core indicate sediment input of organic-poor material. Water isotope data derived from pore ice show a permanently frozen state of the lower core parts and only represent precipitation water very close to the surface. Therefore, it is unlikely that strong organic matter decomposition took place in this Yedoma core. Also, these core parts consist of more coarse material. Fine sand is found here instead of the silty material that makes up most of the cores. This change in material input was dated to a timespan between 39 000 and 18 000 years before present. During this time, climate experienced variations on a global as well as on a regional scale, which could have influenced the availability of liquid water as well as thaw depth and wind regimes. Especially the changes in wind direction and velocity are likely to have influenced the material composition. The sandy material found is not originating from surrounding areas but could be transported over greater distances. These findings indicate that Yedoma might be more heterogeneous on a global scale than previously thought, making it important to further study Yedoma deposits. Both general carbon content as well as carbon vulnerability, for example due to alternating sediment characteristics within a Yedoma deposit, might be very different. It can be assumed that, before thermokarst processes occured, the core drilled within the alas basin had quite similar characteristics as the Yedoma core. This indicates possible developing characteristics of Yedoma deposits during ongoing climate change. A possible reason for this is increasing lake formation in Arctic areas due to warming air temperatures, which in turn can lead to further carbon release with further permafrost thaw, enhancing a positive feedback cycle in Northern permafrost areas

Large Herbivores and Their Interaction with Arctic Soil Carbon Storage

Permafrost degradation and organic matter decomposition in the terrestrial Arctic are strongly depending on soil temperatures. A factor that affects these temperatures is grazing and snow trampling by large herbivorous animals, as well as animal-induced changes in vegetation cover. We analysed samples taken from adjacent areas with different grazing intensities, both in a permafrost environment (Siberia) and seasonally frozen ground (norther Finland) for TOC, C/N ratio, d13C, bulk density and radiocarbon age. While in permafrost there was a strong increase in soil carbon storage with high grazing intensity, this effect is not visible in seasonally frozen ground. However, in both areas we observed massive changes in vegetation composition and structure, following the grazing gradient. We conclude that seasonally frozen ground allows for more intensive carbon relocation and mixing, which outweighs the effects animals have in the permafrost region but state that on permafrost, animals might efficiently be utilized to stabilise permafrost temperatures and reduce organic material decomposition

Herbivore-Induced Effects on Arctic Soil Carbon Storage

Permafrost degradation and organic matter decomposition in the terrestrial Arctic are strongly depending on soil temperature throughout the year. These temperatures are affected in numerous ways by activity of large herbivorous animals. We identified snow compaction and animal-induced vegetation changes as key elements. Therefore, we analysed soil parameters along transects following grazing intensity in both a permafrost environment (northeastern Siberia) and seasonally frozen ground (norther Finland). Parameters included TOC, C/N ratio, d13C, bulk density and radiocarbon age. While we observed a strong increase in soil carbon storage with high grazing intensity under permafrost conditions, this effect does not show in seasonally frozen ground. However, an obvious animal-induced change in both areas was a shift in vegetation composition and structure, following the grazing gradient. We conclude that material and water fluxes in seasonally frozen ground outweigh the animals’ effects, contrary to permafrost environments, but state that on permafrost, animals could help maintaining low soil temperatures and hence reduce organic material decomposition

Heterogeneity of Yedoma Ice Complex deposits due to regional genesis processes

Yedoma Ice Complex is a type of permafrost characterized by high ice content and carbon content of approx. 2 wt%. The high ice content makes it very vulnerable to thawing in terms of global warming. Previously stored organic material becomes available for microbial decomposition, releasing carbon into the atmosphere. But Yedoma deposits might be more heterogenous than previously thought. This is indicated by findings from the Yukechi Alas landscape in Central Yakutia where Yedoma deposits with a lack of carbon for several meters are found. Analysis reveals shifts in regional sedimentary processes as a plausible solution to the found heterogenity, making it important to further investigate the composition of Yedoma Ice Complex deposits throughout the arctic. Such heterogenity may change the proposed amount of carbon stored in those deposits but may as well have effects on thaw behaviour and vulnerability to climate warming. Therefore, more information is needed on the scope of such regional influences in order to increase knowledge about the effects of thawing Yedoma on climate change

Stable isotope signatures of Holocene syngenetic permafrost trace seabird presence in the Thule District (NW Greenland)

Holocene permafrost from ice wedge polygons in the vicinity of large seabird breeding colonies in the Thule District, NW Greenland, was drilled to explore the relation between permafrost aggradation and seabird presence. The latter is reliant on the presence of the North Water Polynya (NOW) in the northern Baffin Bay. The onset of peat accumulation associated with the arrival of little auks (Alle alle) in a breeding colony at Annikitisoq, north of Cape York, is radiocarbon-dated to 4400 cal BP. A thick-billed murre (Uria lomvia) colony on Appat (Saunders Island) in the mouth of the Wolstenholme Fjord started 5650 cal BP. Both species provide marine-derived nutrients (MDNs) that fertilize vegetation and promote peat growth. The geochemical signature of organic matter left by the birds is traceable in the frozen Holocene peat. The peat accumulation rates at both sites are highest after the onset, decrease over time, and were about 2-times faster at the little auk site than at the thick-billed murre site. High accumulation rates induce shorter periods of organic matter (OM) decomposition before it enters the perennially frozen state. This is seen in comparably high C=N ratios and less depleted 13C, pointing to a lower degree of OM decomposition at the little auk site, while the opposite pattern can be discerned at the thick-billed murre site. Peat accumulation rates correspond to 15N trends, where decreasing accumulation led to increasing depletion in 15N as seen in the little-auk-related data. In contrast, the more decomposed OM of the thick-billed murre site shows almost stable 15N. Late Holocene wedge ice fed by cold season precipitation was studied at the little auk site and provides the first stable-water isotopic record from Greenland with mean 18O of 8:00:8, mean D of 36:25:7, mean d excess of 7:70:7, and a 18O-D slope of 7.27, which is close to those of the modern Thule meteoric water line. The syngenetic ice wedge polygon development is mirrored in testacean records of the little auk site and delineates polygon low-center, dry-out, and polygon-high-center stages. The syngenetic permafrost formation directly depending on peat growth (controlled by bird activity) falls within the period of neoglacial cooling and the establishment of the NOW, thus indirectly following the Holocene climate trends

Large herbivores on permafrost— a pilot study of grazing impacts on permafrost soil carbon storage in northeastern Siberia

The risk of carbon emissions from permafrost is linked to an increase in ground temperature and thus in particular to thermal insulation by vegetation, soil layers and snow cover. Ground insulation can be influenced by the presence of large herbivores browsing for food in both winter and summer. In this study, we examine the potential impact of large herbivore presence on the soil carbon storage in a thermokarst landscape in northeastern Siberia. Our aim in this pilot study is to conduct a first analysis on whether intensive large herbivore grazing may slow or even reverse permafrost thaw by affecting thermal insulation through modifying ground cover properties. As permafrost soil temperatures are important for organic matter decomposition, we hypothesize that herbivory disturbances lead to differences in ground-stored carbon. Therefore, we analyzed five sites with a total of three different herbivore grazing intensities on two landscape forms (drained thermokarst basin, Yedoma upland) in Pleistocene Park near Chersky. We measured maximum thaw depth, total organic carbon content, δ13C isotopes, carbon-nitrogen ratios, and sediment grain-size composition as well as ice and water content for each site. We found the thaw depth to be shallower and carbon storage to be higher in intensively grazed areas compared to extensively and non-grazed sites in the same thermokarst basin. First data show that intensive grazing leads to a more stable thermal ground regime and thus to increased carbon storage in the thermokarst deposits and active layer. However, the high carbon content found within the upper 20 cm on intensively grazed sites could also indicate higher carbon input rather than reduced decomposition, which requires further studies including investigations of the hydrology and general ground conditions existing prior to grazing introduction. We explain our findings by intensive animal trampling in winter and vegetation changes, which overcompensate summer ground warming. We conclude that grazing intensity—along with soil substrate and hydrologic conditions—might have a measurable influence on the carbon storage in permafrost soils. Hence the grazing effect should be further investigated for its potential as an actively manageable instrument to reduce net carbon emission from permafrost

Organic carbon characteristics in ice-rich permafrost in alas and Yedoma deposits, central Yakutia, Siberia

Permafrost ground is one of the largest repositories of terrestrial organic carbon and might become or already is a carbon source in response to ongoing global warming. With this study of syngenetically frozen, ice-rich and organic carbon (OC)-bearing Yedoma and associated alas deposits in central Yakutia (Republic of Sakha), we aimed to assess the local sediment deposition regime and its impact on permafrost carbon storage. For this purpose, we investigated the Yukechi alas area (61.76495°N, 130.46664°E), which is a thermokarst landscape degrading into Yedoma in central Yakutia. We retrieved two sediment cores (Yedoma upland, 22.35m deep, and alas basin, 19.80m deep) in 2015 and analyzed the biogeochemistry, sedimentology, radiocarbon dates and stable isotope geochemistry. The laboratory analyses of both cores revealed very low total OC (TOC) contents (< 0.1 wt %) for a 12m section in each core, whereas the remaining sections ranged from 0.1 wt% to 2.4 wt% TOC. The core sections holding very little to no detectable OC consisted of coarser sandy material were estimated to be between 39 000 and 18 000 BP (years before present) in age. For this period, we assume the deposition of organic-poor material. Pore water stable isotope data from the Yedoma core indicated a continuously frozen state except for the surface sample, thereby ruling out Holocene reworking. In consequence, we see evidence that no strong organic matter (OM) decomposition took place in the sediments of the Yedoma core until today. The alas core from an adjacent thermokarst basin was strongly disturbed by lake development and permafrost thaw. Similar to the Yedoma core, some sections of the alas core were also OC poor (< 0.1 wt %) in 17 out of 28 samples. The Yedoma deposition was likely influenced by fluvial regimes in nearby streams and the Lena River shifting with climate. With its coarse sediments with low OC content (OC mean of 5.27 kg m-3), the Yedoma deposits in the Yukechi area differ from other Yedoma sites in North Yakutia that were generally characterized by silty sediments with higher OC contents (OC mean of 19 kg m-3 for the non-icewedge sediment). Therefore, we conclude that sedimentary composition and deposition regimes of Yedoma may differ considerably within the Yedoma domain. The resulting heterogeneity should be taken into account for future upscaling approaches on the Yedoma carbon stock. The alas core, strongly affected by extensive thawing processes during the Holocene, indicates a possible future pathway of ground subsidence and further OC decomposition for thawing central Yakutian Yedoma deposits

25 years of joint Yedoma Ice Complex studies in Arctic Russia, especially in Sakha/Yakutia

Since 1994, permafrost deposits of the Siberian Yedoma region have been in the focus of the joint Russian-German scientific cooperation in terrestrial Polar research (Figure 1). These studies focused on cryostratigraphic, geochemical, geochronological, and paleontological characteristics at more than 25 individual study sites of the late Pleistocene Yedoma Ice Complex in Siberia and provided a detailed insight into the paleoenvironments and paleoclimate for the westernmost part of Beringia. The multidisciplinary investigations resulted in new ideas and discussions in the ongoing scientific debate on the origin of Yedoma Ice Complex and the main periglacial processes involved in its formation (1,2,3). The Yedoma Ice Complex is an ice-rich type of permafrost deposit widely distributed across Beringia. The Ice Complex aggradation is mainly controlled by the growth of syngenetic ice wedge polygons contributing up to 60 vol% of the entire formation. The clastic sedimentation of ice-oversaturated Yedoma deposits with considerable organic matter content is further controlled by local conditions such as source rocks and periglacial weathering processes, paleotopography, and temporary surface stabilization with autochthonous peat growth and soil formation. Key processes include alluvial, fluvial, and niveo-aeolian transport (4) as well as accumulation in ponding waters and continued in-situ frost weathering over millennial time-scales. Important post-depositional processes affecting Yedoma deposits are solifluction, cryoturbation, and pedogenesis. Major joint Russian-German field studies were conducted on Taymyr Peninsula (5,6,7,8,9,10,11), along the western and central Laptev Sea coasts (12,13,14,15,16,17,18), in the Lena Delta (19,20,21,22), on islands of the New Siberian Archipelago (23,24,25,26,27,28), and the adjacent mainland (29). Further study sites were conducted in the Kolyma Lowland (30), the Yana Highlands (31,32), in the foothills of the Verkhoyan Mountains (33,34,35,36), and in Central Yakutia (37). Comprehensive sampling and further analytical work included not only the Yedoma Ice Complex itself but also included its stratigraphic context of older underlying sequences and younger overlying deposits. The latter often are subaerial or subaquatic deposits associated with late-Glacial to Holocene thermokarst dynamics that led to Yedoma degradation during the deglacial and Holocene warming of these regions (38,39,40). Figure 1: Joint Russian-German fieldwork sites in NE Siberia labeled with the year of expedition. Besides geomorphological and cryolithological studies, extensive paleo-ecological investigations were carried out on zoological (41,42,43,44,45) and botanic fossils (46,47,48,49,50,51) to derive quantitative and qualitative reconstructions late Pleistocene Beringian environments and climate conditions. New methods in geochronology were also tested (52,53,54,55). In addition to the sedimentary components of the frozen deposits, segregated ground ice and in particular the large syngenetic ice wedges of Yedoma Ice Complex were also studied as geochemical and stable isotope archives of paleoclimate (56,57,58, 59,60,61,62). In addition, a range of remote sensing methods in combination with GIS analyses (63,64,65) and geophysical surveys (66) were used for large-scale analyses of landscape changes associated with Yedoma Ice Complex degradation (67,68,69). In the last few years, an additional important focus has been on using modern biogeochemical methods of organic matter analysis to characterize the frozen organic matter in Yedoma Ice Complex deposits and for permafrost carbon pool calculations (70, 71,72,73,74,75,76,77) as well as microbiological studies (78) and genetic studies on fossil DNA (79,80). The rich body of scientific data and literature produced in Russian-German co-authorship within the more than 25 years of joint research on Yedoma Ice Complex represents an important cornerstone for understanding the Late Quaternary evolution of Siberian Yedoma regions, its role in the Earth System, and its feedbacks with climate and ecosystems. References 1. Schirrmeister, L., Dietze, E., Matthes, H., Grosse, G., Strauss, J., Laboor, S., Ulrich, M., Kienast, F., and Wetterich, S. (2020) The genesis of Yedoma Ice Complex permafrost – grain-size endmember modeling analysis from Siberia and Alaska, E&G Quaternary Sci. J., 69, 33–53, doi: 10.5194/egqsj-69-33-2020. 2. Schirrmeister, L., Froese, D., Tumskoy, V., Grosse,G., Wetterich, S. (2013.) Yedoma: Late Pleistocene ice-rich syngenetic permafrost of Beringia. In: Elias S.A. (ed.) The Encyclopedia of Quaternary Science 2nd edition, vol. 3, pp. 542-552. Amsterdam: Elsevier. 3. Schirrmeister, L., Kunitsky, V.V., Grosse, G., Wetterich, S., Meyer, H., Schwamborn, G., Babiy, O., Derevyagin, A.Y., and Siegert, C.: Sedimentary characteristics and origin of the Late Pleistocene Ice Complex on North-East Siberian Arctic coastal lowlands and islands - a review. Quaternary International 241, 3-25, doi: 10.1016/j.quaint.2010.04.004, 2011. 4. Kunitsky, V., Schirrmeister, L., Grosse, G., Kienast, F. (2002). Snow patches in nival landscapes and their role for the Ice Complex formation in the Laptev Sea coastal lowlands, Polarforschung, 70, 53-67, doi:10.2312/polarforschung.70.53. 5. Andreev, A. , Siegert, C. , Klimanov, V. A. , Derevyagin, A. Y. , Shilova, G. N. and Melles, M. (2002) Late Pleistocene and Holocene vegetation and climate changes in the Taymyr lowland, Northern Siberia Quaternary research, 57, pp. 138-150 . 6. Andreev, A. , Tarasov, P. E. , Siegert, C. , Ebel, T. , Klimanov, V. A. , Melles, M. , Bobrov, A. A. , Derevyagin, A. Y. , Lubinski, D. J. and Hubberten, H. W. (2003) Vegetation and climate changes on the northern Taymyr, Russia during the Upper Pleistocene and Holocene reconstructed from pollen records , Boreas, 32 (3), pp. 484-505 . 7. Chizhov, A. B. , Derevyagin, A. Y. , Simonov, E. F. , Hubberten, H. W. and Siegert, C. (1997) Isotopic composition of ground ice at the Labaz Lake region (Taymyr). Kriosfera Zemlii (Earth Cryoshere), 1, No 3, pp. 79-84 . (in Russian), 8. Derevyagin, A.Yu., Chizhov, A.B., Brezgunov, V.S., Siegert, C., Hubberten, H.-W., 1999.Isotopic composition of ice wedges of Cape Sabler (Lake Taymyr). Kriosfera Zemlii (Earth Cryosphere) 3/3, 41-49 (in Russian). 9. Kienast, F., Siegert, C., Dereviagin, A., Mai, H.D. Climatic implications of Late Quaternary plant macrofossil assemblages from the Taymyr Peninsula, Siberia, Global and Planetary Change, Volume 31, Issues 1–4, 265-281, 2001, https://doi.org/10.1016/S0921-8181(01)00124-2. 10. Kienel, U. , Siegert, C. and Hahne, J. (1999) Late Quarternary paeloenvironmental reconstruction from a permafrost sequence (Northsiberian Lowland, SE Taymyr Peninsula) - a multidisciplinary case study, Boreas, 28 (1), pp. 181-193 . 11. Siegert C., Derevyagin A.Y., Shilova G.N., Hermichen WD., Hiller A. (1999) Paleoclimatic Indicators from Permafrost Sequences in the Eastern Taymyr Lowland. In: Kassens H. et al. (eds) Land-Ocean Systems in the Siberian Arctic. Springer, Berlin, Heidelberg. 12. Bobrov, A.A., Müller, S., Chizhikova, N.A., Schirrmeister, L., Andreev, A.A.(2009).Testate Amoebae in Late Quaternary Sediments of the Cape Mamontov Klyk (Yakutia), Biology Bulletin, 36(4), 363-372. 13. Schirrmeister, L., Grosse, G., Kunitsky, V., Magens, D., Meyer, H., Dereviagin, A., Kuznetsova, T., Andreev, A., Babiy, O., Kienast, F., Grigoriev, M., Overduin, P.P., and Preusser, F.: Periglacial landscape evolution and environmental changes of Arctic lowland areas for the last 60,000 years (Western Laptev Sea coast, Cape Mamontov Klyk), Polar Research, 27(2), 249-272, doi: 10.1111/j.1751-8369.2008.00067.x, 2008. 14. Winterfeld, M., Schirrmeister, L., Grigoriev, M., Kunitsky, V.V., Andreev, A., and Overduin, P.P.: Permafrost and Landscape Dynamics during the Late Pleistocene, Western Laptev Sea Shelf, Siberia, Boreas 40(4), 697–713, doi: 10.1111/j.1502-3885.2011.00203.x, 2011. 15. Siegert, C., Schirrmeister, L., and Babiy, O.: The sedimentological, mineralogical and geochemical composition of late Pleistocene deposits from the ice complex on the Bykovsky peninsula, northern Siberia, Polarforschung, 70, 2000, 3-11, doi: 10.2312/polarforschung.70.3, 2002. 16. Schirrmeister, L., Siegert, C., Kuznetsova, T., Kuzmina, S., Andreev, A.A., Kienast, F., Meyer, H., and Bobrov, A.A.: Paleoenvironmental and paleoclimatic records from permafrost deposits in the Arctic region of Northern Siberia, Quaternary International, 89, 97-118, doi: 10.1016/S1040-6182(01)00083-0, 2002. 17. Schirrmeister, L., Siegert, C., Kunitzky, V.V., Grootes, P.M., and Erlenkeuser, H.: Late Quaternary ice-rich permafrost sequences as a paleoenvironmental archive for the Laptev Sea Region in northern Siberia, International Journal of Earth Sciences, 91, 154-167, doi: 10.1007/s005310100205, 2002. 18. Schirrmeister, L., Schwamborn, G., Overduin, P.P., Strauss, J., Fuchs, M.C., Grigoriev, M., Yakshina, I., Rethemeyer, J., Dietze, E., and Wetterich, S.: Yedoma Ice Complex of the Buor Khaya Peninsula (southern Laptev Sea), Biogeosciences 14, 1261-1283, doi: 10.5194/bg-14-1261-2017, 2017. 19. Schirrmeister, L., Kunitsky, V.V., Grosse, G., Schwamborn, G., Andreev, A.A., Meyer, H., Kuznetsova, T., Bobrov, A., and Oezen, D.: Late Quaternary history of the accumulation plain north of the Chekanovsky Ridge (Lena Delta, Russia) - a multidisciplinary approach, Polar Geography, 27(4), 277-319, doi: 10.1080/789610225, 2003. 20. Schirrmeister, L., Grosse, G. Schnelle, M., Fuchs, M., Krbetschek, M., Ulrich, M., Kunitsky, V., Grigoriev, M., Andreev, A. Kienast, F., Meyer, H., Klimova, I., Babiy, O., Bobrov, A., Wetterich, S., and Schwamborn, G.: Late Quaternary paleoenvironmental records from the western Lena Delta, Arctic Siberia, Palaeogeography, Palaeoclimatology, Palaeoecology 299, 175–196, doi: 10.1016/j.quascirev.2009.11.017, 2011. 21. Schwamborn, G., Rachold, V., and Grigoriev, M.N.: Late Quaternary sedimentation history of the Lena Delta, Quaternary International 89, 119–134, doi: 10.1016/S1040-6182(01)00084-2, 2002. 22. Wetterich, S., Kuzmina, S., Andreev, A.A., Kienast, F., Meyer, H., Schirrmeister, L., Kuznetsova, T., and Sierralta, M.: Palaeoenvironmental dynamics inferred from late Quaternary permafrost deposits on Kurungnakh Island, Lena Delta, Northeast Siberia, Russia, Quaternary Science Reviews, 27, 1523-1540, doi: 10.1016/j.quascirev.2008.04.007, 2008. 23. Andreev, A.A., Grosse, G., Schirrmeister, L., Kuzmina, S.A., Novenko, E.Yu., Bobrov, A.A., Tarasov, P. E., Kuznetsova, T.V., Krbetschek, M., Meyer, H., and Kunitsky, V.V.: Late Saalian and Eemian palaeoenvironmental history of the Bol'shoy Lyakhovsky Island (Laptev Sea region, Arctic Siberia), Boreas 33(4), 319-348, doi:10.1080/03009480410001974, 2004. 24. Andreev, A., Grosse, G., Schirrmeister, L., Kuznetsova, T.V., Kuzmina, S.A., Bobrov, A.A., Tarasov, P.E., Novenko, E.Yu., Meyer, H., Derevyagin, A.Yu., Kienast, F., Bryantseva, A., and Kunitsky, V.V.: Weichselian and Holocene palaeoenvironmental history of the Bol’shoy Lyakhovsky Island, New Siberian Archipelago, Arctic Siberia, Boreas 38(1), 72–110, doi: 10.1111/j.1502-3885.2008.00039.x, 2009. 25. Wetterich, S., Rudaya, N., Meyer, H., Opel, T., and Schirrmeister, L.: Last Glacial Maximum records in permafrost of the East Siberian Arctic, Quaternary Science Reviews 30, 3139-3151, doi: 10.1016/j.quascirev.2011.07.020, 2011. 26. Wetterich, S., Rudaya, N., Andreev, A.A., Opel, T., Schirrmeister, L., Meyer, H., and Tumskoy, V.: Ice Complex formation in arctic East Siberia during the MIS3 Interstadial, Quaternary Science Reviews 84: 39-55, doi:. 10.1016/j.quascirev.2013.11.009, 2014. 27. Wetterich, S.; Tumskoy:V.E., Rudaya, N., Kuznetsov, V., Maksimov, F., Opel T. , Meyer H., Andreev, A.A., Schirrmeister, L (2016) Ice Complex permafrost of MIS5 age in the Dmitry Laptev Strait coastal region (East Siberian Arctic). Quaternary Science Reviews, 147:298-31, doi.org/10.1016/j.quascirev.2015.11.016. 28. Wetterich, S., Rudaya, N., Kuznetsov V., Maksimov, F., T. Opel, Meyer, H., Guenther, F., Bobrov, A., Raschke, E., Zimmermann, H., Strauss, J., Fuchs, M.C., Schirrmeister, L. (2019) Recurrent Ice Complex formation in arctic eastern Siberia since about 200 ka. Quaternary Research 92 (2); 530-548, doi.org/10.1017/qua.2019.6. 29. Wetterich, S., Schirrmeister, L., Andreev A. A., Pudenz, M., Plessen, B, Meyer, H., Kunitsky, V. V. (2009). Eemian and Late Glacial/Holocene palaeoenvironmental records from permafrost sequences at the Dmitry Laptev Strait (NE Siberia, Russia), Palaeogeography, Palaeoclimatology, Palaeoecology 279: 73-95 doi:10.1016/j.palaeo.2009.05.002. 30. Strauss, J., Schirrmeister, L., Wetterich, S., Borchers, A, and Davydov S.P.: Grain-size properties and organic-carbon stock of Yedoma Ice Complex permafrost from the Kolyma lowland, northeastern Siberia. GBC. 26: GB3003, doi: 10.1029/2011GB004104, 2012. 31. Ashastina, K., Schirrmeister, L., Fuchs M., and Kienast F.: Palaeoclimate characteristics in interior Siberia of MIS 6–2: first insights from the Batagay permafrost mega-thaw slump in the Yana Highlands, Clim. Past, 13, 795–818, doi: 10.5194/cp-13-795-2017, 2017. 32. Kunitsky, V.V., Syromyatnikov, I.I., Schirrmeister, L., Skachkov, Yu.B., Grosse, G., Wetterich, S., and Grigoriev, M.N.: Ice-rich permafrost and thermal denudation in the Kirgillyakh area, Kriosfera Zemli. 17(1), 56-68, 2013 (in Russian). 33. Popp, S., Diekmann,B., Meyer, H., Siegert, C.,Syromyatnikov, I., Hubberten, H.-W. Palaeoclimate Signals as Inferred from Stable-isotope Composition of Ground Ice in the Verkhoyansk Foreland, Central Yakutia. Permafrost and Periglac. Process. 17: 119–132 (2006) DOI: 10.1002/ppp.556 34. Popp, S., Belolyubsky, I., Lehmkuhl, F., Prokopiev, A., Siegert, C., Spektor, V., Stauch, G., Diekmann,B. Sediment provenance of late Quaternary morainic, fluvialand loess-like deposits in the southwestern VerkhoyanskMountains (eastern Siberia) and implications for regionalpalaeoenvironmental reconstructions. Geol. J.42: 477–497 (2007), DOI: 10.1002/gj.1088 35. Siegert, C. , Sergeyenko, A. I. and Schirrmeister, L. (2017) Late Quaternary Deposits of the Northern Verkhoyansk Mountains: Geochronology and Questions of their Genesis (in Russian), Bulletin of the Commission for Study of the Quaternary = БЮЛЛЕТЕНЬ КОМИССИИ ПО ИЗУЧЕНИЮ ЧЕТВЕРТИЧНОГО ПЕРИОДА, 75 , pp. 100-112 . 36. Siegert, C. , Stauch, G. , Lehmkuhl, F. , Sergeyenko, A. I. , Diekmann, B. , Popp, S. and Belolyubsky, I. N. (2007) Development of glaciation in the Verkhoyansk Range and its foreland during the Pleistocene: Results of new investigations., Regionalnaya Geologiya i Metallogeniya (Regional Geology and Metallogeny), No. 30-31(in Russian)., 222 . 37. Ulrich, M., Morgenstern, A., Günther, F., Reiss, D. Bauch, K. E., Hauber, E., Rössler, S. and Schirrmeister, L. (2010) Thermokarst in Siberian ice-rich permafrost: Comparison to asymmetric scalloped depressions on Mars, Journal of Geophysical Research, 115, E10009 . doi:10.1029/2010JE003640 , 38. Morgenstern, A. , Grosse, G. , Günther, F. , Fedorova, I. and Schirrmeister, L. (2011): Spatial analyses of thermokarst lakes and basins in Yedoma landscapes of the Lena Delta. The Cryosphere, 5(4), 849–867, doi:10.5194/tc-5-849-2011. 39. Morgenstern, A. , Ulrich, M. , Günther, F. , Roessler, S. , Fedorova, I. V. , Rudaya, N. A. , Wetterich, S. , Boike, J. and Schirrmeister, L. (2013). Evolution of thermokarst in East Siberian ice-rich permafrost: A case study, Geomorphology, 201 , 363-379. doi:10.1016/j.geomorph.2013.07.011 40. Biskaborn, B. , Herzschuh, U. , Bolshiyanov, D. Y. , Schwamborn, G. and Diekmann, B. (2013) Thermokarst Processes and Depositional Events in a Tundra Lake, Northeastern Siberia, Permafrost and Periglac. Process.24: 160–174 doi:https://doi.org/10.1002/ppp.1769, 41. Kuznetsova, T. V. , Sulerzhitsky, L. D. , Andreev, A. , Siegert, C. , Schirrmeister, L. and Hubberten, H. W. (2003) Influence of Late Quaternary paleoenvironmental conditions on the distribution of mammals fauna in the Laptev Sea region , Occasional Papers in Earth Sciences, 5 , pp. 58-60 . 42. Kuznetsova T.V., Tumskoy V.E., Schirrmeister L., Wetterich S., (2019.) Paleozoological characteristics of the Late Neo-Pleistocene - Holocene sediments of Bykovsky Peninsula, Northern Yakutia (Палеозоологическая характеристика поздненеоплейстоценовых – голоценовых отложений Быковского Полуострова (Северная Якутия). Zoological Journal 98(11), 1268-1290. Special issue in honor of Andrey Sher. (in Russian) doi: 10.1134/S0044513419110102. 43. Bobrov, A. A. , Andreev, A. , Schirrmeister, L. and Siegert, C. (2004) Testate amoebae (Protozoa: Testacea) as bioindicators in the Late Quaternary deposits of the Bykovsky Peninsula, Laptev Sea, Russia , Palaeogeography palaeoclimatology palaeoecology, 209 , pp. 165-181 . doi:https://doi.org/10.1016/J.PALAEO.2004.02.012 44. Wetterich, S., Schirrmeister, L., Pietrzeniuk, E. (2005). Freshwater ostracodes in Quaternary permafrost deposits from the Siberian Arctic, Journal of Paleolimnology, 34, 363-376. doi:10.1007/s10933-005-5801-y 45. Müller, S., Bobrov, A. A., Schirrmeister, L., Andreev, A. A., Tarasov, P. E. (2009). Testate amoebae record from the Laptev Sea coast and its implication for the reconstruction of Late Pleistocene and Holocene environments in the Arctic Siberia, Palaeogeography, Palaeoclimatology, Palaeoecology 271(3-4), 301-315. doi:10.1016/j.palaeo.2008.11.003 46. Andreev, A.A., Schirrmeister, L., Siegert, C., Bobrov, A.A., Demske, D., Seiffert, M., Hubberten, H.-W. (2002). Paleoenvironmental changes in Northeastern Siberia during the Late Quaternary - evidence from pollen records of the Bykovsky Peninsula, Polarforschung, 70, 13-25, doi:10.2312/polarforschung.70.13. 47. Andreev, A.A.; Schirrmeister, L.; Tarasov , P.E.; Ganopolski , A.; Brovkin V.; Siegert, C.; Hubberten, H.-W. (2011). Vegetation and climate history in the Laptev Sea region (arctic Siberia) during Late Quaternary inferred from pollen records. Journal of Quaternary science reviews. 30, 2182-2199 doi:10.1016/j.quascirev.2010.12.026. 48. Kienast, F. , Schirrmeister, L. , Siegert, C. and Tarasov, P. (2005) Palaeobotanical evidence for warm summers in the East Siberian Arctic during the last cold stage, Quaternary Research, 63 (3), pp. 283-300. doi:https://doi.org/10.1016/j.yqres.2005.01.003 , 49. Kienast, F., Tarasov, P., Schirrmeister, L., Grosse, G., Andreev, A.A. (2008). Continental climate in the East Siberian Arctic during the last interglacial: implications from palaeobotanical records, Global and Planetary Change, 60(3/4), 535-562. doi:10.1016/j.gloplacha.2007.07.004 50. Kienast, F., Wetterich, S., Kuzmina, S., Schirrmeister, L., Andrev, A., Tarasov, P., Nazarova, L., Kossler, A., Frolova, A., Kunitsky, V. V.(2011) Paleontological records indicate the occurrence of open woodlands in a dry inland climate at the present-day Arctic coast in western Beringia during the last interglacial. Quaternary Science Reviews 30: 2134-2159, doi:10.1016/j.quascirev.2010.11.024. 51. Palagushkina, O.V., Wetterich, S., Schirrmeister, L., Nazarova, L.B. (2017) Modern and fossil diatom assemblages from Bol'shoy Lyakhovsky Island (New Siberian Archipelago, Arctic Siberia). Contemporary Problems of Ecology, 10, (4), 380–394. doi: 10.1134/S1995425517040060. 52. Gilichinsky, D. A. , Nolte, E., Basilyan, A.E., Beer, J., Blinov, A., Lazarev, V., Kholodov, A., Meyer, H., Nikolsky, P.A., Schirrmeister, L., Tumskoy, V. (2007). Dating of syngenetic ice wedges in permafrost with 36Cl and 10Be, Quaternary science reviews. 26, 1547-1556. doi:10.1016/j.quascirev.2007.04.004 53. Blinov A.V., Beer J., Tikhomirov D.A., Schirrmeister L., Meyer H., Abramov A.A., Basylyan A.E., Nikolskiy P.A., Tumskoy V.E., Kholodov A.L., Gilichinsky D.A. (2009) Permafrost dating with the cosmogenic radionuclides ( Report 1) (= Датирование многолетнемерзлых пород с помощью космогенных радионуклидов (сообщение 1). Kriosfera Zemli 13,( 2), 3-15 (in Russian). 54. Blinov, A., Alfimov, V., Beer, J., Gilichinsky, D., Schirrmeister, L., Kholodov, A., Nikolskiy, P., Opel, T., Tikhomirov, D., Wetterich, S.(2009).36Cl/Cl ratio in ground ice of East Siberia and its application for chronometry, Geochemistry, Geophysics, Geosystems (G3). 10(1), doi: 10.1029/2009GC002548. 55. Schirrmeister, L., Oezen, D., Geyh, M.A. (2002). 230Th/U dating of frozen peat, Bol'shoy Lyakhovsky Island (North Siberia), Quaternary research, 57, 253-258. doi:10.1006/qres.2001.2306. 56. Meyer, H. , Derevyagin, A. Y. , Siegert, C. and Hubberten, H. W. (2002) Paleoclimate studies on Bykovsky Peninsula, North Siberia - hydrogen and oxygen isotopes in ground ice , Polarforschung 70:, pp. 37-51 . 57. Derevyagin, A. Y., Chizhov, A. , Meyer, H. , Opel, T. , Schirrmeister, L. and Wetterich, S. (2013). Isotopic composition of texture ices, Laptev Sea coast , Kriosfera Zemlii (Earth Cryosphere), XVII (3), pp. 27-34 (in Russian). 58. Meyer, H. , Derevyagin, A. Y. , Siegert, C. , Schirrmeister, L. and Hubberten, H. W. (2002) Paleoclimate reconstruction on Big Lyakhovsky Island, North Siberia - Hydrogen and oxygen isotopes in ice wedges , Permafrost and periglacial processes, 13 , pp. 91-105 . 59. Opel, T., Dereviagin, A., Meyer, H., Schirrmeister, L., Wetterich, S. (2010).Paleoclimatic information from stable water isotopes of Holocene ice wedges at the Dmitrii Laptev Strait (Northeast Siberia), Permafrost and Periglacial Processes. 22 (1), 84-100, doi:10.1002/ppp.667. 60. Opel, T., Wetterich, S., Meyer, H., Dereviagin, A.Yu., Fuchs, M.C., and Schirrmeister, L.: Ground-ice stable isotopes and cryostratigraph