Serpentine (Floating) Ice Channels and their Interaction with Riverbed Permafrost in the Lena River Delta, Russia

Juhls, Bennet; Antonova, Sofia; Angelopoulos, Michael; Bobrov, Nikita; Grigoriev, Mikhail N.; Langer, Moritz; Maksimov, Georgii; Miesner, Frederieke; Overduin, Paul

doi:10.3389/feart.2021.689941

Cited by 16 publications

(7 citation statements)

References 70 publications

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“…Future decreasing ice thickness and broader sub-ice pathways will further increase the connectivity of Arctic rivers. This connectivity could account for increased winter runoff signals (Juhls et al 2021 ) as observed here (Fig. 3 a, b).…”

Section: Discussionsupporting

confidence: 69%

Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes

Mann

Strauß

Palmtag

et al. 2021

Ambio

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Arctic warming is causing ancient perennially frozen ground (permafrost) to thaw, resulting in ground collapse, and reshaping of landscapes. This threatens Arctic peoples' infrastructure, cultural sites, and land-based natural resources. Terrestrial permafrost thaw and ongoing intensification of hydrological cycles also enhance the amount and alter the type of organic carbon (OC) delivered from land to Arctic nearshore environments. These changes may affect coastal processes, food web dynamics and marine resources on which many traditional ways of life rely. Here, we examine how future projected increases in runoff and permafrost thaw from two permafrost-dominated Siberian watersheds—the Kolyma and Lena, may alter carbon turnover rates and OC distributions through river networks. We demonstrate that the unique composition of terrestrial permafrost-derived OC can cause significant increases to aquatic carbon degradation rates (20 to 60% faster rates with 1% permafrost OC). We compile results on aquatic OC degradation and examine how strengthening Arctic hydrological cycles may increase the connectivity between terrestrial landscapes and receiving nearshore ecosystems, with potential ramifications for coastal carbon budgets and ecosystem structure. To address the future challenges Arctic coastal communities will face, we argue that it will become essential to consider how nearshore ecosystems will respond to changing coastal inputs and identify how these may affect the resiliency and availability of essential food resources.

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Section: Discussionsupporting

confidence: 69%

Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes

Mann

Strauß

Palmtag

et al. 2021

Ambio

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“…However, available maps did not cover these areas, and as such no statement on water depths in the main Lena River channels can be made with our bathymetrical data set. Also, Juhls et al (2021) found several smaller channel continuations offshore the Lena Delta which are undetected even with our high-resolution bathymetry.…”

Section: Challenges and Limitations Of The Bathymetry Modelsmentioning

confidence: 55%

“…The accuracy and resolution of the two data sets provide important spatial information about the depth distribution in the coastal zones of the Lena Delta and Kolyma Gulf regions and give an indication of the offshore continuation of the main river channels. In combination with detailed mapping of deep channels in Arctic river deltas (Juhls et al, 2021), our new data set will improve the modeling of freshwater pathways as it transitions from land to ocean.…”

Section: Potential Applications and Usage Of The Data Setsmentioning

confidence: 99%

High-resolution bathymetry models for the Lena Delta and Kolyma Gulf coastal zones

Fuchs

Palmtag

Juhls

et al. 2022

Earth Syst. Sci. Data

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Abstract. Arctic river deltas and deltaic near-shore zones represent important land–ocean transition zones influencing sediment dynamics and nutrient fluxes from permafrost-affected terrestrial ecosystems into the coastal Arctic Ocean. To accurately model fluvial carbon and freshwater export from rapidly changing river catchments as well as assess impacts of future change on the Arctic shelf and coastal ecosystems, we need to understand the sea floor characteristics and topographic variety of the coastal zones. To date, digital bathymetrical data from the poorly accessible, shallow, and large areas of the eastern Siberian Arctic shelves are sparse. We have digitized bathymetrical information for nearly 75 000 locations from large-scale (1:25 000–1:500 000) current and historical nautical maps of the Lena Delta and the Kolyma Gulf region in northeastern Siberia. We present the first detailed and seamless digital models of coastal zone bathymetry for both delta and gulf regions in 50 and 200 m spatial resolution. We validated the resulting bathymetry layers using a combination of our own water depth measurements and a collection of available depth measurements, which showed a strong correlation (r>0.9). Our bathymetrical models will serve as an input for a high-resolution coupled hydrodynamic–ecosystem model to better quantify fluvial and coastal carbon fluxes to the Arctic Ocean, but they may be useful for a range of other studies related to Arctic delta and near-shore dynamics such as modeling of submarine permafrost, near-shore sea ice, or shelf sediment transport. The new digital high-resolution bathymetry products are available on the PANGAEA data set repository for the Lena Delta (https://doi.org/10.1594/PANGAEA.934045; Fuchs et al., 2021a) and Kolyma Gulf region (https://doi.org/10.1594/PANGAEA.934049; Fuchs et al., 2021b), respectively. Likewise, the depth validation data are available on PANGAEA as well (https://doi.org/10.1594/PANGAEA.933187; Fuchs et al., 2021c).

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“…This allows the representation of a freezing curve for free water with a discrete phase change at 0 • C. We emphasize that this is a good first-order approximation for sandy and organic-rich sediments such as those present at the study site. The uncoupled soil-heat model was successfully applied to determine the thickness and shape of taliks beneath serpentine river channels in the Lena-Delta (Juhls et al, 2021). The coupling between FLake and CryoGrid at the top of the sediment domain was achieved by applying the bottom water temperature provided by FLake as the upper boundary condition to the sediment domain.…”

Section: Soil Heatmentioning

confidence: 99%

Simulated methane emissions from Arctic ponds are highly sensitive to warming

Rehder

Kleinen

Kutzbach

et al. 2023

Preprint

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Abstract. We employ a new, process-based model for methane emissions from ponds (MeEP) to investigate the methane-emission response of polygonal-tundra ponds in Northeast Siberia to warming. Small and shallow water bodies such as ponds are vulnerable to warming due to their low thermal inertia compared to larger lakes, and the Arctic is warming at an above-average rate. While ponds are a relevant landscape-scale source of methane under the current climate, the response of pond methane emissions to warming is uncertain. MeEP differentiates between the three main pond types of the polygonal tundra, ice-wedge, polygonal-center, and merged polygonal ponds. The model resolves the three main pathways of methane emissions – diffusion, ebullition, and plant-mediated transport – at the temporal resolution of one hour, thus capturing daily and seasonal variability of the methane emissions. The model was tuned using chamber measurements resolving the three methane pathways. We perform idealized warming experiments, with increases in the mean annual temperature of 2.5, 5, and 7.5 °C on top of a historical simulation. The simulations reveal an overall increase of 1.33 g CH4 year-1 °C-1 per square meter of pond area. Under annual temperatures 5 °C above present temperatures pond methane emissions are more than three times higher than now. Most of this emission increase is due to the additional substrate provided by the increased net productivity of the vascular plants. Furthermore, plant-mediated transport is the dominating pathway of methane emissions in all simulations. We conclude that vascular plants as a substrate source and efficient methane pathway should be included in future pan-Arctic assessments of pond methane emissions.

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Serpentine (Floating) Ice Channels and their Interaction with Riverbed Permafrost in the Lena River Delta, Russia

Cited by 16 publications

References 70 publications

Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes

Degrading permafrost river catchments and their impact on Arctic Ocean nearshore processes

High-resolution bathymetry models for the Lena Delta and Kolyma Gulf coastal zones

Simulated methane emissions from Arctic ponds are highly sensitive to warming

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