Short-term dynamics of a low-centred ice-wedge polygon near Chokurdakh (NE Yakutia, NE Siberia) and climate change during the last ca 1250 years

Palaeoecological studies (including analysis of pollen, macrofossils, geochemistry, and AMS radiocarbon dates) of four peat sections from one low-centred ice-wedge polygon in NE Yakutia (NE Siberia) allow the three-dimensional reconstruction of polygon development during the last ca 1250 years. After drainage of a lake, peat forming vegetation invaded rapidly. Comparison with palaeotemperature data shows that the initial formation of mature ridges coincided with a period of high summer temperatures around AD 1400. The ridges persisted and expanded during the subsequent colder ca 200 years. Partial collapse of various ridges at the end of the 18th century corresponded to a phase with low summer temperatures. During the warm, 20th century one collapsed ridge regenerated, whereas another persisted in its collapsed state. Ice-wedge polygons are, thus, complex and highly dynamic ecosystems, in which changes in temperature and precipitation may induce rapid ecological changes by the complex interplay of water, ice and vegetation. Our study indicates that global warming associated with a decrease in summer precipitation may initially result in enhanced polygon ridge formation. The combination of longer summers and increased winter precipitation, as predicted for high latitudes will, however, eventually result in larger meltwater input in the polygon mires, which may cause the (partial) collapse of polygon ridges and underlying ice-wedges.

► Development of an ice-wedge polygon.
► Polygon ridges formed during warm phases.
► Polygon ridges collapsed during cold phases.
► Different ridges/ridge parts react differently.
► Complex interplay of water, ice, vegetation, peat.