Postglacial wetland development of NW Varanger Peninsula, N Norway
2024
Nikolaeva, Margarita
Assessing the future behaviour of northern peatland ecosystems and their large soil organic carbon stocks with in a warming climate is an important area of research. Understanding past changes in climate and how they influenced northern peatlands and their carbon stocks since the last deglaciation could help to make projections for future scenarios. Due to their vulnerability to warming and thawing, peatlands affected by permafrost have received much scientific attention. In this work, nine cores from arctic-alpine wetlands in the northeastern part of Varanger Peninsula, northern Norway, were analysed using a multi-proxy analysis. Prior to this study, there has not been conducted any research on wetlands in a cold periglacial but permafrost free tundra environment. The earliest observed initiation of peatland started around 7100 cal. yr BP with additional inception dates between 5750 cal. yr BP and 2900 cal. yr BP. The peatlands were formed through paludification and can be characterized as wet fens during most of its historical development. Dryer peat conditions during the Holocene Thermal Maximum could be recognized through plant macrofossil analysis. Colder conditions during the Little Ice Age led to induced periglacial activity and isolated peat hummock development in wet fens. SOC stocks within all analyzed cores ranged between 17.92 and 97.47 kg C m-2 for peat between 44 and 108 cm in depth. Mean SOC stock in 783,000 m2 of analysed wetlands in the study area was 43.7 kg C m-2 . Long-term C accumulation rates ranged between 5.00 and 12.98 g C m -2 a -1. Peat basal ages are relatively young and peat depths, peat SOC stocksand C accumulation rates relatively low compared to those in boreal and subarctic peatlands in the interior of northern Fennoscandia.
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