Description: Samoylov Island is centrally located within the Lena River Delta at 72° N, 126° E and lies within the Siberian zone of continuous permafrost. The landscape on Samoylov Island consists mainly of late Holocene river terraces with polygonal tundra, ponds and lakes, and an active floodplain. The island has been the focus of numerous multidisciplinary studies since 1993, which have focused on climate, land cover, ecology, hydrology, permafrost and limnology. This paper aims to provide a framework for future studies by describing the characteristics of the island's meteorological parameters (temperature, radiation and snow cover), soil temperature, and soil moisture. The land surface characteristics have been described using high resolution aerial images in combination with data from ground-based observations. Of note is that deeper permafrost temperatures have increased between 0.3 to 1.3 °C over the last five years. However, no clear warming of air and active layer temperatures is detected since 1998, though winter air temperatures during recent years have not been as cold as in earlier years.

Description: The northeastern part of Eurasia represents one of Earth‟s most extreme periglacial climate regions, characterized by the strongest seasonal temperature amplitudes on the northern hemisphere. The region is occupied by deep-reaching permafrost and covered by widespread taiga and tundra vegetation (Müller et al., 2010). Paleoenvironmental studies have been conducted close to the northern polar cycle in the Verkhoyansk Mountain Range and its western foreland to infer periglacial landscape dynamics in response to late Quaternary climate change. The distribution of preserved terminal moraines reveal several mountain glacier advances in the past (Stauch and Lehmkuhl, 2010). According to luminescence dating, the widest geologically documented glacial advence took place during the Saalian stage around 135 ka. Less extended glaciations to the foreland appeared during the early Weichselian at 100-120 ka and at 85-90 ka, while the youngest glaciation (〉50 ka) was confined to the mountain area. No regional glacial advance is evident for the late Weichselian and the last glacial maximum, a time which was characterized by aeolian loess formation (Stauch et al., 2007, Popp et al., 2007). Sediment cores from the 25 m deep Lake Billyakh (340 m a.s.l.), a former proglacial basin, document environmental changes of the last 50 kyr (Diekmann et al., 2007). Pollen records indicate a dry climate for the late Weichselian, indicated by a change from tundra towards cold steppe vegetation after 32 ka until 13.5 ka BP (Müller et al., 2009, 2010). For the same time, sedimentological and diatom data indicate a lake level drop. Modelling experiments with a general circulation model suggest that the consecutive decline in the extent of mountain glaciers and increase in dryness through the Weichselian was dictated by the growing shielding effect of the western Eurasian ice sheets that prevented the supply of moist Atlantic air masses to eastern Siberia (Krinner et al., 2011). In addition, enhanced deposition of dust reduced the albedo and promoted ice and snow melting during summer (Krinner et al., 2011). Environmental changes towards interglacial conditions of the Holocene are documented in the Lake Billyakh deposits (Müller et al., 2009) as well as in a peat section at Dyanushka River (Werner et al., 2009). Both records show that climate amelioration started after 13.5 ka BP with the quick return of larch trees that also persisted during the Younger Dryas cold spell, suggesting that the Verkhoyansk Mountain area possibly represented a plant refugium during the climate extremes of the last ice age (Tarasov et al., 2009). Reforestation continued since 11.4 ka BP with the spread of boreal cold deciduous and taiga forests and reached a maximum extent after 7 ka BP. Limnological conditions of Lake Billyakh changed to a higher lake-level and increased biological productivity consistent with climate warming and increased humidity. Mean July air temperatures reconstructed by fossil aquatic chironomids, using a regional inference model (Nazarova et al., 2011), indicate warmest summer temperatures between roughly 9.0 and 6.6 ka BP. The stable-isotope composition of ice wedges in permafrost soils point to warmer winters during the early Holocene compared to the late Holocene (Popp et al, 2006). The recognition of a regional early Holocene climate optimum is consistent with long-term Holocene climate development in wide parts of northern Eurasia. References Diekmann, B., Andreev, A.A., Müller, G., Lüpfert, H., Pestryakova, L., Subetto, D., 2007. Expedition 'Verkhoyansk 2005' - Limnogeological studies at Lake Billyakh, Verkhoyansk Mountains, Yakutia. In: Schirrmeister, L. (ed.): Expeditions in Sibiria in 2005, Reports on Polar and Marine Research, 550: 247-258. Krinner, G., Diekmann, B., Colleoni, F., Stauch, G., 2011. Global, regional and local scale factors determining glaciation. Quaternary Science Reviews, 30: 821-831. Müller, S., Tarasov, P. E., Andreev, A., Diekmann, B., 2009. Late Glacial to Holocene environments in the present-day coldest region of the Northern Hemisphere inferred from a pollen record of Lake Billyakh, Verkhoyansk Mts ., NE Siberia. Climate of the Past 5: 73-84. Müller, S., Tarasov, P.E., Andreev, A.A., Tuetken, T., Gartz, S., Diekmann, B., 2010. Late Quaternary vegetation and environments in the Verkhoyansk Mountains region (NE Asia) reconstructed from a 50-kyr fossil pollen record from Lake Billyakh. Quaternary Science Reviews, 29: 2071-2086. Nazarova, L., Herzschuh, U., Wetterich, S., Kumke, T., Pestryakova, L., 2011. Chironomid-based inference models for estimating mean July air temperature and water depth from lakes in Yakutia, northeastern Russia. Journal of Paleolimnology, 45(1): 57-71. Popp, S., Belolyubsky, I., Lehmkuhl, F., Prokopiev, A., Siegert, C., Spektor, V., Stauch, G., Diekmann, B. (2007): Sediment provenance of late Quaternary morainic, fluvial and loess-like deposits in the southwestern Verkhoyansk Mountains (eastern Siberia) and implications for regional palaeoenvironmental reconstructions. Geological Journal, 42: 477-497. Popp, S., Diekmann, B., Meyer, H., Siegert, C., Syromyatnikov, I., Hubberten, H. W., 2006. Palaeoclimate signals as inferred from stable-isotope composition of ground ice in the Verkhoyansk foreland, Central Yakutia. Permafrost and Periglacial Processes, 17: 119-132. Stauch, G., Lehmkuhl, F., 2010. Quaternary glaciations in the Verkhoyansk Mountains, Northeast Siberia. Quaternary Research, 74: 145-155. Stauch, G., Lehmkuhl, F., Frechen, M., 2007. Luminescence chronology from the Verkhoyansk Mountains (North-Eastern Siberia). Quaternary Geochronology, 2: 255-259. Tarasov, P., Müller, S., Andreev, A., Werner, K., Diekmann, B., 2009. Younger Dryas Larix in eastern Siberia: A migrant or survivor? PAGES News, 17(3): 122-123. Werner, K., Tarasov, P.E., Andreev, A.A., Müller, S., Kienast, F., Zech, M., Zech, W., Diekmann, B., 2009. A 12.5-kyr history of vegetation dynamics and mire development with evidence of Younger Dryas larch presence in the Verkhoyansk Mountains, East Siberia, Russia. Boreas, 39(1): 56-68.

Description: Fossil diatom assemblages in a sediment core from a small lake in Central Kamchatka (Russia) were used to reconstruct palaeoenvironmental conditions of the late Holocene. The waterbody may be a kettle lake that formed on a moraine of the Two-Yurts Lake Valley, located on the eastern slope of the Central Kamchatka Mountain Chain. At present, it is a seepage lake with no surficial outflow. Fossil diatom assemblages show an almost constant ratio between planktonic and periphytic forms throughout the record. Downcore variations in the relative abundances of diatom species enabled division of the core into four diatom assemblage zones, mainly related to changes in abundances of Aulacoseira subarctica, Stephanodiscus minutulus, and Discostella pseudostelligera and several benthic species. Associated variations in the composition and content of organic matter are consistent with the diatom stratigraphy. The oldest recovered sediments date to about 3220 BC. They lie below a sedimentation hiatus and likely include reworked deposits from nearby Two-Yurts Lake. The initial lake stage between 870 and 400 BC was characterized by acidic shallow-water conditions. Between 400 BC and AD 1400, lacustrine conditions were established, with highest contributions from planktonic diatoms. The interval between AD 1400 and 1900 might reflect summer cooling during the Little Ice Age, indicated by diatoms that prefer strong turbulence, nutrient recycling and cooler summer conditions. The timing of palaeolimnological changes generally fits the pattern of neoglacial cooling during the late Holocene on Kamchatka and in the neighbouring Sea of Okhotsk, mainly driven by the prevailing modes of regional atmospheric circulation.

Description: Microorganisms inhabit very different soil habitats in the ice-free areas of Antarctica, playing a major role in nutrient cycling in cold environments. We studied the soil characteristics and the dominant bacterial composition from nine different soil profiles located on Livingston Island (maritime Antarctica). The total carbon (TC) and total nitrogen (TN) values were high for the vegetated soils, decreasing with depth, whereas the values for the mineral soils were generally low. Soil pH was more acidic for moss-covered soils and neutral to alkaline for mineral soils. Numbers of culturable heterotrophic bacteria were higher at vegetated sites, but significant numbers were also detectable in carbon-depleted soils. Patterns of denaturing gradient gel electrophoresis (DGGE) revealed a highly heterogeneous picture throughout the soil profiles. Subsequent sequencing of DGGE bands revealed in total 252 sequences that could be assigned to 114 operational taxonomic units, showing the dominance of members of the Bacteroidetes and Acidobacteria. The results of phospholipid fatty acid analysis showed a lack of unsaturated fatty acids for most of the samples. Samples with a prevalence of unsaturated over saturated fatty acids were restricted to several surface samples. Statistical analysis showed that the dominant soil bacterial community composition is most affected by TC and TN contents and soil physical factors such as grain size and moisture, but not pH. Keywords

Description: This study investigates the rate of erosion during the 1951-2006 period on the Bykovsky Peninsula, located north-east of the harbour town of Tiksi, north Siberia. Its coastline, which is characterized by the presence of ice-rich sediment (Ice Complex) and the vicinity of the Lena River Delta, retreated at a mean rate of 0.59 m/yr between 1951 and 2006. Total erosion ranged from 434 m of erosion to 92 m of accretion during these 56 years and exhibited large variability (sigma = 45.4). Ninety-seven percent of the rates observed were less than 2 m/yr and 81.6% were less than 1 m/yr. No significant trend in erosion could be recorded despite the study of five temporal subperiods within 1951-2006. Erosion modes and rates actually appear to be strongly dependant on the nature of the backshore material, erosion being stronger along low-lying coastal stretches affected by past or current thermokarst activity. The juxtaposition of wind records monitored at the town of Tiksi and erosion records yielded no significant relationship despite strong record amplitude for both data sets. We explain this poor relationship by the only rough incorporation of sea-ice cover in our storm extraction algorithm, the use of land-based wind records vs. offshore winds, the proximity of the peninsula to the Lena River Delta freshwater and sediment plume and the local topographical constraints on wave development.