Biogeochemical Processes in the Active Layer and Permafrost of a High Arctic Fjord Valley

Jones, Ε. L.; Hodson, Andy; Thornton, Steven F.; Redeker, K. R.; Rogers, J. W.; Wynn, P.; Dixon, Timothy J.; Bottrell, Simon H.; O'Neill, H B

doi:10.3389/feart.2020.00342

Cited by 12 publications

(23 citation statements)

References 88 publications

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“…In Adventdalen, organic carbon content and the degree of water saturation exert an important control on the prevailing biogeochemical processes, as has been observed in saturated active layer sediments (this study and Jones et al 24 ). The sediments of the low-centered polygons of Adventdalen North are water-saturated, rich in organic carbon, and anaerobic, with iron and sulfate reduction leading to the precipitation of pyrite and siderite.…”

Section: Summary and Predictions Of The Impact Of Permafrost Thawsupporting

confidence: 70%

“…Jones 49 reported up to 6462 μmol L À1 carbon dioxide (as carbon dioxide, excluding bicarbonate) in active layer pore water of core N1 from Adventdalen North. In contrast, less iron reduction is evidenced at Revneset.…”

Section: Biogeochemical Processes Driving Carbon Dioxide Productionmentioning

confidence: 99%

“…Different operationally defined iron mineral phases were targeted with a four-step sequential extraction procedure applied to 100 mg of freeze-dried and milled sediment from one core at each site, following procedures from Raiswell et al, 43 from Poulton and Canfield, 44 and detailed in Jones et al 24 The phases extracted were…”

Section: Solid Phase Analysesmentioning

confidence: 99%

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Biogeochemistry of low‐ and high‐centered ice‐wedge polygons in wetlands in Svalbard

Jones

Hodson

Redeker

et al. 2023

Permafrost & Periglacial

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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 highcentered (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 lowcentered 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.

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Section: Summary and Predictions Of The Impact Of Permafrost Thawsupporting

confidence: 70%

Section: Biogeochemical Processes Driving Carbon Dioxide Productionmentioning

confidence: 99%

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Biogeochemistry of low‐ and high‐centered ice‐wedge polygons in wetlands in Svalbard

Jones

Hodson

Redeker

et al. 2023

Permafrost & Periglacial

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“…Furthermore, the inundation of the North Sea Basin was a prolonged event, mainly occurring between 12 to 6 kyr BP 24 , with different areas inundated at different stages 25 . This gradual cutting off of potential sulfate sources from North Sea sediments is inconsistent with the rapid rise in faunal d 34 S values seen at the end of the LPSE.…”

mentioning

confidence: 78%

“…In addition, the 34 S-depleted sulfides can be taken up directly by plants if they can tolerate sulfide toxicity or if they are able to re-oxidise the sulfides to SO4 2through transporting oxygen to their roots 2,33 . A study on sulfate d 34 S of pore waters from saturated permafrost ice-wedge polygons in Svalbard reported DSR preferentially reduced 34 S in this context, and the product H2S was incorporated into organic matter 34 . Permafrost thaw and development of thermokarst conditions also has a significant impact on hydrological processes across landscapes.…”

Section: : Permafrost Development and Thawmentioning

confidence: 95%

Major excursions in sulfur isotopes linked to permafrost change in Eurasia during the last 50,000 Years.

Stevens

Reade

Sayle

et al. 2023

Preprint

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Widespread permafrost thaw is underway as arctic regions warm at twice the rate of the global average. Greenhouse gases (methane and carbon dioxide) released from thawing organic-rich permafrost soils contribute to a positive feedback loop that further accelerates global warming. There is an urgent need to understand the relationship between past permafrost conditions and palaeoclimatic change, to better predict present permafrost response to ongoing and future climate change. Through sulfur isotope analysis (δ34S) of radiocarbon-dated bone collagen samples spanning the last 50,000 years, we have identified what we term a high-magnitude Late Pleniglacial Sulfur Excursion (LPSE) in Eurasia. This anomaly is geographically widespread and several orders of magnitude higher than the sulfur isotope variation previously attributed to changing animal origin or diet alone. We show that a major change in the terrestrial sulfur cycle related to continental-scale environmental processes are, in this context, representing changing permafrost conditions. Sulfur isotope analysis of faunal samples offer an unrivalled prospect of developing high-resolution, tightly chronologically-constrained records of past permafrost change in relation to global climate changes. This would inform on the sensitivity of permafrost to past climate change, enabling constraints to be put on modelled responses of present‐day permafrost to future climate change. More broadly, our findings indicate animal δ34S values may reflect local environmental conditions, complicating the use of δ34S values as a tool for food origin, animal migration, and archaeological palaeodiet and mobility research.

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Spatial and temporal patterns of near‐surface ground temperature in the Arctic mountain catchment

Kasprzak

Szymanowski

2023

Land Degrad Dev

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We consider the case of a mountain catchment representative of southwest Spitsbergen to investigate the spatial and temporal variation in temperature of the near‐surface ground. We set up 20 thermistor strings distributed in different parts of the catchment, combine the measured data with land surface temperature (LST) retrieved from Landsat imagery, and verify the depth of ground thawing using electrical resistivity tomography. Under current climatic conditions, the thickness of the active layer (ALT) is at least 1.5 m, and in the lower parts of the catchment, between 3.5 and 4 m. The maximum ground surface temperature in the study area can be 27°C, and the temperature at a depth of 1.5 m, 5.4°C. We identified unfrozen ground (taliks) to a depth of 10–30 m in zones of water concentration at foot slopes and under river channels. The persistence of year‐round taliks at lake shores is possible. We verify the hypothesis that topographic parameters significantly determine the spatial variation of near‐surface ground temperature. For each level of temperature aggregation (from 6 h to 12 months data) and each examined the depth of the active layer, it is possible to identify environmental variables—related to energy conditions, heights, terrain relief, and ground surface moisture—significantly correlated with ground temperature, and consequently to specify multiple regression models. Topographic exposure and LST (used only in daily models), altitude, and various approximations of relative height are crucial in their construction. The ground temperature variance, unexplained in the regression analysis, prompts recognition of the critical role of factors not included in the modelling (groundwater, soil structure).

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Biogeochemical Processes in the Active Layer and Permafrost of a High Arctic Fjord Valley

Cited by 12 publications

References 88 publications

Biogeochemistry of low‐ and high‐centered ice‐wedge polygons in wetlands in Svalbard

Biogeochemistry of low‐ and high‐centered ice‐wedge polygons in wetlands in Svalbard

Major excursions in sulfur isotopes linked to permafrost change in Eurasia during the last 50,000 Years.

Spatial and temporal patterns of near‐surface ground temperature in the Arctic mountain catchment

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