4000 Years of Changing Wetness in a Permafrost Polygon Peatland (Kytalyk, NE Siberia): A Comparative High‐Resolution Multi‐Proxy Study

Abstract

Ice-wedge polygon mires feature a micro-relief of dry ridges, shallow wet depressions, deeper wet troughs and transitional sites, resulting in a local mosaic of vegetation. The correct recognition of these landscape elements in palaeoecological studies of peat sections requires insight about the suitability of proxies and their potential for palaeoecological reconstruction in order to reconstruct vegetation and wetness patterns as well as dynamics. This paper analyses a 105.5 cm long peat section with a base dating to about 4000 cal yr BP from an ice-wedge polygon mire near Kytalyk (NE Siberia). Pollen, macrofossils, testate amoebae, geochemistry and sediment properties were analysed in order to compare the suitability of these proxies to reconstruct past surface wetness. The proxies show similar wetness trends. Pollen and geochemistry data did not always permit wetness reconstruction, the former because many pollen types do not allow the identification of taxa at a low taxonomic resolution, the latter because later taphonomic processes modify chemical variables in deeper peat layers. Macrofossils provided the most detailed wetness reconstruction, because they could be identified to genera or species, for which the moisture requirements are accurately known from their present-day distribution in ice-wedge polygons. All proxies, except geochemistry, show an obvious change from wet to dry conditions at around 20 cm depth. However, as the proxies sometimes show contradictory results, a multi-proxy approach is preferable over a single proxy interpretation as it allows the reconstruction of environmental development in a broader palaeoecological context. Figure 2 Location of ice-wedge polygon Lhc11 near the Kytalyk research station along the Berelekh River: (A, B) the study area, indicated are the most important landforms; (C) satellite image of the study area (GeoEye image from 2010, 0.5 m resolution, by courtesy of K. van Huissteden, Vrije Universiteit, Faculty of Earth and Life Sciences, Amsterdam); and (D) ice-wedge polygon Lhc11. This figure is available in colour online at wileyonlinelibrary.com/journal/ppp 78 A. Teltewskoi et al.

Vegetation Succession, Carbon Accumulation and Hydrological Change in Subarctic Peatlands, Abisko, Northern Sweden

“…In the bottom part of both peat sequences the main peat‐forming plants included Cyperaceae (Figure , phase A; Figure , phases A and B). The presence of Carex fruits and rootlets, as well as brown mosses in both sites indicates that during this period the peatlands operated as fens, a widespread wetland type in the permafrost area of the northern hemisphere (Vardy et al , ; Kuhry, ; Teltewskoi et al , ; Treat et al , ). Pollen data indicate that between 2650 and 2300 cal yr BP the non‐peatland community at Marooned was dominated by Betula .…”

Thaw pond development and initial vegetation succession in experimental plots at a Siberian lowland tundra site

“…This tundra zone is considered at high risk of thaw subsidence (Nelson et al 2001). There are many observations of recent thermokarst, the thawing of ice-rich permafrost causing soil subsidence, redistribution of water and changes in vegetation composition in lowland tundra areas in Alaska (Jorgenson et al 2006Jones et al 2015), western Canada (Wolter et al 2016), and eastern Siberia (Fedorov et al 2014, Liljedahl et al 2016, Teltewskoi et al 2016, indicating that abrupt permafrost thaw is widespread. In lowlands, the soil subsidence results in new open water features such as ice wedge troughs, thermokarst pits or thaw ponds in which the pre-existing dwarf shrub vegetation drowns.…”

“…Ice-wedge low-center polygons are abundant in the wetter part of the drained lake basin, many of the polygons are in a degraded stage (Fig. 1, Teltewskoi et al 2016). Both the experiment plots and natural thaw ponds are located on irregular frost mounds dominated by B. nana (Siewert et al 2015).…”

Permafrost thaw and release of inorganic nitrogen from polygonal tundra soils in eastern Siberia

“…This profile was excavated from a pit, 1.1 m deep. A detailed description of the profile IND-1-R is given by Teltewskoi et al (2016). Eight pairs of soil cores were drilled (0.5 m to each other) in the Kolyma River Delta near Pokhodsk (Schirrmeister et al, 2016).…”

“…A detailed description of the profile IND-1-R is given by Teltewskoi et al (2016). Eight pairs of soil cores were drilled (0.5 m to each other) in the Kolyma River Delta near Pokhodsk (Schirrmeister et al, 2016). The soil cores labelled as KOL-X-X were used for analyses of the soil chemistry, and the soil cores labelled as 12P were used for cryolithological studies.…”