Eleanor L. Jones, A. Hodson, K. Redeker, H. Christiansen, S. Thornton, Jade Rogers
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Biogeochemistry of low‐ and high‐centered ice‐wedge polygons in wetlands in Svalbard
Arctic wetlands are a globally significant store of soil organic carbon. They are often characterized by ice‐wedge polygons, which are diagnostic of lowland permafrost, and which greatly influence wetland hydrology and biogeochemistry during summer. The degradation of ice‐wedge polygons, which can occur in response to climate change or local disturbance, has poorly understood consequences for biogeochemical processes. We therefore used geochemical analyses from the active layer and top permafrost to identify and compare the dominant biogeochemical processes in high‐centered (degraded) and low‐centered (pristine) polygons situated in the raised beach sediments and valley‐infill sediments of Adventdalen, Central Svalbard. We found similar organic‐rich sediments in both cases (up to 38 dry wt.%), but while low‐centered polygons were water‐saturated, their high‐centered counterparts had a relatively dry active layer. Consequently, low‐centered polygons showed evidence of iron and sulfate reduction leading to the precipitation of pyrite and siderite, whilst the high‐centered polygons demonstrated more oxidizing conditions, with decreased iron oxidation and low preservation of iron and sulfate reduction products in the sediments. This study thus demonstrates the profound effect of ice‐wedge polygon degradation on the redox chemistry of the host sediment and porewater, namely more oxidizing conditions, a decrease in iron reduction, and a decrease in the preservation of iron and sulfate reduction products.
期刊介绍:
Permafrost and Periglacial Processes is an international journal dedicated to the rapid publication of scientific and technical papers concerned with earth surface cryogenic processes, landforms and sediments present in a variety of (Sub) Arctic, Antarctic and High Mountain environments. It provides an efficient vehicle of communication amongst those with an interest in the cold, non-glacial geosciences. The focus is on (1) original research based on geomorphological, hydrological, sedimentological, geotechnical and engineering aspects of these areas and (2) original research carried out upon relict features where the objective has been to reconstruct the nature of the processes and/or palaeoenvironments which gave rise to these features, as opposed to purely stratigraphical considerations. The journal also publishes short communications, reviews, discussions and book reviews. The high scientific standard, interdisciplinary character and worldwide representation of PPP are maintained by regional editorial support and a rigorous refereeing system.