TY  - JOUR
A1  - Tape, Ken D.
A1  - Jones, Benjamin M.
A1  - Arp, Christopher D.
A1  - Nitze, Ingmar
A1  - Grosse, Guido
T1  - Tundra be dammed
BT  - beaver colonization of the arctic
JF  - Global change biology
N2  - Increasing air temperatures are changing the arctic tundra biome. Permafrost is thawing, snow duration is decreasing, shrub vegetation is proliferating, and boreal wildlife is encroaching. Here we present evidence of the recent range expansion of North American beaver (Castor canadensis) into the Arctic, and consider how this ecosystem engineer might reshape the landscape, biodiversity, and ecosystem processes. We developed a remote sensing approach that maps formation and disappearance of ponds associated with beaver activity. Since 1999, 56 new beaver pond complexes were identified, indicating that beavers are colonizing a predominantly tundra region (18,293km(2)) of northwest Alaska. It is unclear how improved tundra stream habitat, population rebound following overtrapping for furs, or other factors are contributing to beaver range expansion. We discuss rates and likely routes of tundra beaver colonization, as well as effects on permafrost, stream ice regimes, and freshwater and riparian habitat. Beaver ponds and associated hydrologic changes are thawing permafrost. Pond formation increases winter water temperatures in the pond and downstream, likely creating new and more varied aquatic habitat, but specific biological implications are unknown. Beavers create dynamic wetlands and are agents of disturbance that may enhance ecosystem responses to warming in the Arctic.
KW  - arctic tundra
KW  - beaver
KW  - climate change
KW  - permafrost
KW  - population recovery
KW  - salmon
KW  - shrub expansion
KW  - stream
Y1  - 2018
U6  - https://doi.org/10.1111/gcb.14332
SN  - 1354-1013
SN  - 1365-2486
VL  - 24
IS  - 10
SP  - 4478
EP  - 4488
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Creighton, Andrea L.
A1  - Parsekian, Andrew D.
A1  - Angelopoulos, Michael
A1  - Jones, Benjamin M.
A1  - Bondurant, A.
A1  - Engram, M.
A1  - Lenz, Josefine
A1  - Overduin, Pier Paul
A1  - Grosse, Guido
A1  - Babcock, E.
A1  - Arp, Christopher D.
T1  - Transient Electromagnetic Surveys for the Determination of Talik Depth and Geometry Beneath Thermokarst Lakes
JF  - Journal of geophysical research : Solid earth
N2  - Thermokarst lakes are prevalent in Arctic coastal lowland regions and sublake permafrost degradation and talik development contributes to greenhouse gas emissions by tapping the large permafrost carbon pool. Whereas lateral thermokarst lake expansion is readily apparent through remote sensing and shoreline measurements, sublake thawed sediment conditions and talik growth are difficult to measure. Here we combine transient electromagnetic surveys with thermal modeling, backed up by measured permafrost properties and radiocarbon ages, to reveal closed-talik geometry associated with a thermokarst lake in continuous permafrost. To improve access to talik geometry data, we conducted surveys along three transient electromagnetic transects perpendicular to lakeshores with different decadal-scale expansion rates of 0.16, 0.38, and 0.58m/year. We modeled thermal development of the talik using boundary conditions based on field data from the lake, surrounding permafrost and a borehole, independent of the transient electromagnetics. A talik depth of 91m was determined from analysis of the transient electromagnetic surveys. Using a lake initiation age of 1400years before present and available subsurface properties the results from thermal modeling of the lake center arrived at a best estimate talk depth of 80m, which is on the same order of magnitude as the results from the transient electromagnetic survey. Our approach has provided a noninvasive estimate of talik geometry suitable for comparable settings throughout circum-Arctic coastal lowland regions.
KW  - geophysics
KW  - permafrost
KW  - thermokarst
KW  - electromagnetic
KW  - lake
Y1  - 2018
U6  - https://doi.org/10.1029/2018JB016121
SN  - 2169-9313
SN  - 2169-9356
VL  - 123
IS  - 11
SP  - 9310
EP  - 9323
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Muster, Sina
A1  - Riley, William J.
A1  - Roth, Kurt
A1  - Langer, Moritz
A1  - Aleina, Fabio Cresto
A1  - Koven, Charles D.
A1  - Lange, Stephan
A1  - Bartsch, Annett
A1  - Grosse, Guido
A1  - Wilson, Cathy J.
A1  - Jones, Benjamin M.
A1  - Boike, Julia
T1  - Size distributions of arctic waterbodies reveal consistent relations in their statistical moments in space and time
JF  - Frontiers in Earth Science
N2  - Arctic lowlands are characterized by large numbers of small waterbodies, which are known to affect surface energy budgets and the global carbon cycle. Statistical analysis of their size distributions has been hindered by the shortage of observations at sufficiently high spatial resolutions. This situation has now changed with the high-resolution (<5 m) circum-Arctic Permafrost Region Pond and Lake (PeRL) database recently becoming available. We have used this database to make the first consistent, high-resolution estimation of Arctic waterbody size distributions, with surface areas ranging from 0.0001 km(2) (100 m(2)) to 1 km(2). We found that the size distributions varied greatly across the thirty study regions investigated and that there was no single universal size distribution function (including power-law distribution functions) appropriate across all of the study regions. We did, however, find close relationships between the statistical moments (mean, variance, and skewness) of the waterbody size distributions from different study regions. Specifically, we found that the spatial variance increased linearly with mean waterbody size (R-2 = 0.97, p < 2.2e-16) and that the skewness decreased approximately hyperbolically. We have demonstrated that these relationships (1) hold across the 30 Arctic study regions covering a variety of (bio)climatic and permafrost zones, (2) hold over time in two of these study regions for which multi-decadal satellite imagery is available, and (3) can be reproduced by simulating rising water levels in a high-resolution digital elevation model. The consistent spatial and temporal relationships between the statistical moments of the waterbody size distributions underscore the dominance of topographic controls in lowland permafrost areas. These results provide motivation for further analyses of the factors involved in waterbody development and spatial distribution and for investigations into the possibility of using statistical moments to predict future hydrologic dynamics in the Arctic.
KW  - permafrost
KW  - hydrology
KW  - waterbodies
KW  - size distribution
KW  - thermokarst
KW  - statistical moments
KW  - ponds
KW  - lakes
Y1  - 2019
U6  - https://doi.org/10.3389/feart.2019.00005
SN  - 2296-6463
VL  - 7
PB  - Frontiers Research Foundation
CY  - Lausanne
ER  - 
TY  - JOUR
A1  - Nitze, Ingmar
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Romanovsky, Vladimir E.
A1  - Boike, Julia
T1  - Remote sensing quantifies widespread abundance of permafrost region disturbances across the Arctic and Subarctic
JF  - Nature Communications
N2  - Local observations indicate that climate change and shifting disturbance regimes are causing permafrost degradation. However, the occurrence and distribution of permafrost region disturbances (PRDs) remain poorly resolved across the Arctic and Subarctic. Here we quantify the abundance and distribution of three primary PRDs using time-series analysis of 30-m resolution Landsat imagery from 1999 to 2014. Our dataset spans four continental-scale transects in North America and Eurasia, covering similar to 10% of the permafrost region. Lake area loss (-1.45%) dominated the study domain with enhanced losses occurring at the boundary between discontinuous and continuous permafrost regions. Fires were the most extensive PRD across boreal regions (6.59%), but in tundra regions (0.63%) limited to Alaska. Retrogressive thaw slumps were abundant but highly localized (< 10(-5)%). Our analysis synergizes the global-scale importance of PRDs. The findings highlight the need to include PRDs in next-generation land surface models to project the permafrost carbon feedback.
Y1  - 2018
U6  - https://doi.org/10.1038/s41467-018-07663-3
SN  - 2041-1723
VL  - 9
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - GEN
A1  - Nitze, Ingmar
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Romanovsky, Vladimir E.
A1  - Boike, Julia
T1  - Remote sensing quantifies widespread abundance of permafrost region disturbances across the Arctic and Subarctic
T2  - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe
N2  - Local observations indicate that climate change and shifting disturbance regimes are causing permafrost degradation. However, the occurrence and distribution of permafrost region disturbances (PRDs) remain poorly resolved across the Arctic and Subarctic. Here we quantify the abundance and distribution of three primary PRDs using time-series analysis of 30-m resolution Landsat imagery from 1999 to 2014. Our dataset spans four continental-scale transects in North America and Eurasia, covering ~10% of the permafrost region. Lake area loss (−1.45%) dominated the study domain with enhanced losses occurring at the boundary between discontinuous and continuous permafrost regions. Fires were the most extensive PRD across boreal regions (6.59%), but in tundra regions (0.63%) limited to Alaska. Retrogressive thaw slumps were abundant but highly localized (<10−5%). Our analysis synergizes the global-scale importance of PRDs. The findings highlight the need to include PRDs in next-generation land surface models to project the permafrost carbon feedback.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 799 
KW  - Carbon cycle
KW  - Climate change
KW  - Cryospheric science
KW  - Environmental sciences
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426171
SN  - 1866-8372
IS  - 799
ER  - 
TY  - JOUR
A1  - Fuchs, Matthias
A1  - Lenz, Josefine
A1  - Jock, Suzanne
A1  - Nitze, Ingmar
A1  - Jones, Benjamin M.
A1  - Strauss, Jens
A1  - Günther, Frank
A1  - Grosse, Guido
T1  - Organic carbon and nitrogen stocks along a thermokarst lake sequence in Arctic Alaska
JF  - Journal of geophysical research : Biogeosciences
N2  - Thermokarst lake landscapes are permafrost regions, which are prone to rapid (on seasonal to decadal time scales) changes, affecting carbon and nitrogen cycles. However, there is a high degree of uncertainty related to the balance between carbon and nitrogen cycling and storage. We collected 12 permafrost soil cores from six drained thermokarst lake basins (DTLBs) along a chronosequence north of Teshekpuk Lake in northern Alaska and analyzed them for carbon and nitrogen contents. For comparison, we included three lacustrine cores from an adjacent thermokarst lake and one soil core from a non thermokarst affected remnant upland. This allowed to calculate the carbon and nitrogen stocks of the three primary landscape units (DTLB, lake, and upland), to reconstruct the landscape history, and to analyze the effect of thermokarst lake formation and drainage on carbon and nitrogen stocks. We show that carbon and nitrogen contents and the carbon-nitrogen ratio are considerably lower in sediments of extant lakes than in the DTLB or upland cores indicating degradation of carbon during thermokarst lake formation. However, we found similar amounts of total carbon and nitrogen stocks due to the higher density of lacustrine sediments caused by the lack of ground ice compared to DTLB sediments. In addition, the radiocarbon-based landscape chronology for the past 7,000years reveals five successive lake stages of partially, spatially overlapping DTLBs in the study region, reflecting the dynamic nature of ice-rich permafrost deposits. With this study, we highlight the importance to include these dynamic landscapes in future permafrost carbon feedback models. Plain Language Summary When permanently frozen soils (permafrost) contain ice-rich sediments, the thawing of this permafrost causes the surface to sink, which may result in lake formation. This process, the thaw of ice-rich permafrost and melting of ground ice leads to characteristic landforms-known as thermokarst. Once such a thaw process is initiated in ice-rich sediments, a thaw lake forms and grows by shoreline erosion, eventually expanding until a drainage pathway is encountered and the lake eventually drains, resulting in a drained thermokarst lake basin. In our study, we show that such a thermokarst-affected landscape north of Teshekpuk Lake in northern Alaska is shaped by repeated thaw lake formation and lake drainage events during the past 7,000years, highlighting the dynamic nature of these landscapes. These landscape-scale processes have a big effect on the carbon and nitrogen stored in permafrost soils. We show that large amounts of carbon (>45kg C/m(2)) and nitrogen (>2.6kg N/m(2)) are stored in unfrozen lake sediments and in frozen soil sediments. The findings are important when considering the potential effect that permafrost thaw has for the global climate through releasing carbon and nitrogen, which was frozen and therefore locked away for millennia, from the active carbon cycle.
Y1  - 2019
U6  - https://doi.org/10.1029/2018JG004591
SN  - 2169-8953
SN  - 2169-8961
VL  - 124
IS  - 5
SP  - 1230
EP  - 1247
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Lenz, Josefine
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Anthony, Katey M. Walter
A1  - Bobrov, Anatoly
A1  - Wulf, Sabine
A1  - Wetterich, Sebastian
T1  - Mid-Wisconsin to Holocene Permafrost and Landscape Dynamics based on a Drained Lake Basin Core from the Northern Seward Peninsula, Northwest Alaska
JF  - Permafrost and Periglacial Processes
N2  - Permafrost-related processes drive regional landscape dynamics in the Arctic terrestrial system. A better understanding of past periods indicative of permafrost degradation and aggradation is important for predicting the future response of Arctic landscapes to climate change. Here, we used a multi-proxy approach to analyse a4m long sediment core from a drained thermokarst lake basin on the northern Seward Peninsula in western Arctic Alaska (USA). Sedimentological, biogeochemical, geochronological, micropalaeontological (ostracoda, testate amoebae) and tephra analyses were used to determine the long-term environmental Early-Wisconsin to Holocene history preserved in our core for central Beringia. Yedoma accumulation dominated throughout the Early to Late-Wisconsin but was interrupted by wetland formation from 44.5 to 41.5ka BP. The latter was terminated by the deposition of 1m of volcanic tephra, most likely originating from the South Killeak Maar eruption at about 42ka BP. Yedoma deposition continued until 22.5ka BP and was followed by a depositional hiatus in the sediment core between 22.5 and 0.23ka BP. We interpret this hiatus as due to intense thermokarst activity in the areas surrounding the site, which served as a sediment source during the Late-Wisconsin to Holocene climate transition. The lake forming the modern basin on the upland initiated around 0.23ka BP and drained catastrophically in spring 2005. The present study emphasises that Arctic lake systems and periglacial landscapes are highly dynamic and that permafrost formation as well as degradation in central Beringia was controlled by regional to global climate patterns as well as by local disturbances. Copyright (c) 2015 John Wiley & Sons, Ltd.
KW  - Beringia
KW  - palaeoenvironmental reconstruction
KW  - thermokarst lake dynamics
KW  - cryostratigraphy
KW  - tephra
KW  - bioindicators
KW  - yedoma
Y1  - 2016
U6  - https://doi.org/10.1002/ppp.1848
SN  - 1045-6740
SN  - 1099-1530
VL  - 27
SP  - 56
EP  - 75
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Nitze, Ingmar
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Arp, Christopher D.
A1  - Ulrich, Mathias
A1  - Fedorov, Alexander
A1  - Veremeeva, Alexandra
T1  - Landsat-Based Trend Analysis of Lake Dynamics across Northern Permafrost Regions
JF  - Remote sensing
N2  - Lakes are a ubiquitous landscape feature in northern permafrost regions. They have a strong impact on carbon, energy and water fluxes and can be quite responsive to climate change. The monitoring of lake change in northern high latitudes, at a sufficiently accurate spatial and temporal resolution, is crucial for understanding the underlying processes driving lake change. To date, lake change studies in permafrost regions were based on a variety of different sources, image acquisition periods and single snapshots, and localized analysis, which hinders the comparison of different regions. Here, we present a methodology based on machine-learning based classification of robust trends of multi-spectral indices of Landsat data (TM, ETM+, OLI) and object-based lake detection, to analyze and compare the individual, local and regional lake dynamics of four different study sites (Alaska North Slope, Western Alaska, Central Yakutia, Kolyma Lowland) in the northern permafrost zone from 1999 to 2014. Regional patterns of lake area change on the Alaska North Slope (-0.69%), Western Alaska (-2.82%), and Kolyma Lowland (-0.51%) largely include increases due to thermokarst lake expansion, but more dominant lake area losses due to catastrophic lake drainage events. In contrast, Central Yakutia showed a remarkable increase in lake area of 48.48%, likely resulting from warmer and wetter climate conditions over the latter half of the study period. Within all study regions, variability in lake dynamics was associated with differences in permafrost characteristics, landscape position (i.e., upland vs. lowland), and surface geology. With the global availability of Landsat data and a consistent methodology for processing the input data derived from robust trends of multi-spectral indices, we demonstrate a transferability, scalability and consistency of lake change analysis within the northern permafrost region.
KW  - lake dynamics
KW  - lake change
KW  - permafrost region
KW  - Landsat
KW  - Alaska
KW  - Siberia
KW  - thermokarst
KW  - trend analysis
KW  - machine-learning
Y1  - 2017
U6  - https://doi.org/10.3390/rs9070640
SN  - 2072-4292
VL  - 9
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Jones, Benjamin M.
A1  - Arp, Christopher D.
A1  - Grosse, Guido
A1  - Nitze, Ingmar
A1  - Lara, Mark J.
A1  - Whitman, Matthew S.
A1  - Farquharson, Louise M.
A1  - Kanevskiy, Mikhail
A1  - Parsekian, Andrew D.
A1  - Breen, Amy L.
A1  - Ohara, Nori
A1  - Rangel, Rodrigo Correa
A1  - Hinkel, Kenneth M.
T1  - Identifying historical and future potential lake drainage events on the western Arctic coastal plain of Alaska
JF  - Permafrost and Periglacial Processes
N2  - Arctic lakes located in permafrost regions are susceptible to catastrophic drainage. In this study, we reconstructed historical lake drainage events on the western Arctic Coastal Plain of Alaska between 1955 and 2017 using USGS topographic maps, historical aerial photography (1955), and Landsat Imagery (ca. 1975, ca. 2000, and annually since 2000). We identified 98 lakes larger than 10 ha that partially (>25% of area) or completely drained during the 62-year period. Decadal-scale lake drainage rates progressively declined from 2.0 lakes/yr (1955-1975), to 1.6 lakes/yr (1975-2000), and to 1.2 lakes/yr (2000-2017) in the ~30,000-km(2) study area. Detailed Landsat trend analysis between 2000 and 2017 identified two years, 2004 and 2006, with a cluster (five or more) of lake drainages probably associated with bank overtopping or headward erosion. To identify future potential lake drainages, we combined the historical lake drainage observations with a geospatial dataset describing lake elevation, hydrologic connectivity, and adjacent lake margin topographic gradients developed with a 5-m-resolution digital surface model. We identified ~1900 lakes likely to be prone to drainage in the future. Of the 20 lakes that drained in the most recent study period, 85% were identified in this future lake drainage potential dataset. Our assessment of historical lake drainage magnitude, mechanisms and pathways, and identification of potential future lake drainages provides insights into how arctic lowland landscapes may change and evolve in the coming decades to centuries.
KW  - Arctic lakes
KW  - drained lake basins
KW  - lake drainage
KW  - permafrost regions
KW  - thermokarst lakes
Y1  - 2020
U6  - https://doi.org/10.1002/ppp.2038
VL  - 31
IS  - 1
SP  - 110
EP  - 127
PB  - Wiley
CY  - New York
ER  - 
TY  - GEN
A1  - Jones, Benjamin M.
A1  - Arp, Christopher D.
A1  - Grosse, Guido
A1  - Nitze, Ingmar
A1  - Lara, Mark J.
A1  - Whitman, Matthew S.
A1  - Farquharson, Louise M.
A1  - Kanevskiy, Mikhail
A1  - Parsekian, Andrew D.
A1  - Breen, Amy L.
A1  - Ohara, Nori
A1  - Rangel, Rodrigo Correa
A1  - Hinkel, Kenneth M.
T1  - Identifying historical and future potential lake drainage events on the western Arctic coastal plain of Alaska
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Arctic lakes located in permafrost regions are susceptible to catastrophic drainage. In this study, we reconstructed historical lake drainage events on the western Arctic Coastal Plain of Alaska between 1955 and 2017 using USGS topographic maps, historical aerial photography (1955), and Landsat Imagery (ca. 1975, ca. 2000, and annually since 2000). We identified 98 lakes larger than 10 ha that partially (>25% of area) or completely drained during the 62-year period. Decadal-scale lake drainage rates progressively declined from 2.0 lakes/yr (1955-1975), to 1.6 lakes/yr (1975-2000), and to 1.2 lakes/yr (2000-2017) in the ~30,000-km(2) study area. Detailed Landsat trend analysis between 2000 and 2017 identified two years, 2004 and 2006, with a cluster (five or more) of lake drainages probably associated with bank overtopping or headward erosion. To identify future potential lake drainages, we combined the historical lake drainage observations with a geospatial dataset describing lake elevation, hydrologic connectivity, and adjacent lake margin topographic gradients developed with a 5-m-resolution digital surface model. We identified ~1900 lakes likely to be prone to drainage in the future. Of the 20 lakes that drained in the most recent study period, 85% were identified in this future lake drainage potential dataset. Our assessment of historical lake drainage magnitude, mechanisms and pathways, and identification of potential future lake drainages provides insights into how arctic lowland landscapes may change and evolve in the coming decades to centuries.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1376 
KW  - Arctic lakes
KW  - drained lake basins
KW  - lake drainage
KW  - permafrost regions
KW  - thermokarst lakes
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-610435
SN  - 1866-8372
IS  - 1
ER  - 
TY  - JOUR
A1  - Arboleda-Zapata, Mauricio
A1  - Angelopoulos, Michael
A1  - Overduin, Pier Paul
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Tronicke, Jens
T1  - Exploring the capabilities of electrical resistivity tomography to study subsea permafrost
JF  - The Cryosphere
N2  - Sea level rise and coastal erosion have inundated large areas of Arctic permafrost. Submergence by warm and saline waters increases the rate of inundated permafrost thaw compared to sub-aerial thawing on land. Studying the contact between the unfrozen and frozen sediments below the seabed, also known as the ice-bearing permafrost table (IBPT), provides valuable information to understand the evolution of sub-aquatic permafrost, which is key to improving and understanding coastal erosion prediction models and potential greenhouse gas emissions. In this study, we use data from 2D electrical resistivity tomography (ERT) collected in the nearshore coastal zone of two Arctic regions that differ in their environmental conditions (e.g., seawater depth and resistivity) to image and study the subsea permafrost. The inversion of 2D ERT data sets is commonly performed using deterministic approaches that favor smoothed solutions, which are typically interpreted using a user-specified resistivity threshold to identify the IBPT position. In contrast, to target the IBPT position directly during inversion, we use a layer-based model parameterization and a global optimization approach to invert our ERT data. This approach results in ensembles of layered 2D model solutions, which we use to identify the IBPT and estimate the resistivity of the unfrozen and frozen sediments, including estimates of uncertainties. Additionally, we globally invert 1D synthetic resistivity data and perform sensitivity analyses to study, in a simpler way, the correlations and influences of our model parameters. The set of methods provided in this study may help to further exploit ERT data collected in such permafrost environments as well as for the design of future field experiments.
Y1  - 2022
U6  - https://doi.org/10.5194/tc-16-4423-2022
SN  - 1994-0424
VL  - 16
SP  - 4423
EP  - 4445
PB  - Copernicus
CY  - Katlenburg-Lindau
ER  - 
TY  - GEN
A1  - Arboleda-Zapata, Mauricio
A1  - Angelopoulos, Michael
A1  - Overduin, Pier Paul
A1  - Grosse, Guido
A1  - Jones, Benjamin M.
A1  - Tronicke, Jens
T1  - Exploring the capabilities of electrical resistivity tomography to study subsea permafrost
T2  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Sea level rise and coastal erosion have inundated large areas of Arctic permafrost. Submergence by warm and saline waters increases the rate of inundated permafrost thaw compared to sub-aerial thawing on land. Studying the contact between the unfrozen and frozen sediments below the seabed, also known as the ice-bearing permafrost table (IBPT), provides valuable information to understand the evolution of sub-aquatic permafrost, which is key to improving and understanding coastal erosion prediction models and potential greenhouse gas emissions. In this study, we use data from 2D electrical resistivity tomography (ERT) collected in the nearshore coastal zone of two Arctic regions that differ in their environmental conditions (e.g., seawater depth and resistivity) to image and study the subsea permafrost. The inversion of 2D ERT data sets is commonly performed using deterministic approaches that favor smoothed solutions, which are typically interpreted using a user-specified resistivity threshold to identify the IBPT position. In contrast, to target the IBPT position directly during inversion, we use a layer-based model parameterization and a global optimization approach to invert our ERT data. This approach results in ensembles of layered 2D model solutions, which we use to identify the IBPT and estimate the resistivity of the unfrozen and frozen sediments, including estimates of uncertainties. Additionally, we globally invert 1D synthetic resistivity data and perform sensitivity analyses to study, in a simpler way, the correlations and influences of our model parameters. The set of methods provided in this study may help to further exploit ERT data collected in such permafrost environments as well as for the design of future field experiments.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1285 
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-571234
SN  - 1866-8372
IS  - 1285
SP  - 4423
EP  - 4445
ER  - 
TY  - JOUR
A1  - Lenz, Josefine
A1  - Wetterich, Sebastian
A1  - Jones, Benjamin M.
A1  - Meyer, Hanno
A1  - Bobrov, Anatoly
A1  - Grosse, Guido
T1  - Evidence of multiple thermokarst lake generations from an 11800-year-old permafrost core on the northern Seward Peninsula, Alaska
JF  - Boreas
N2  - Permafrost degradation influences the morphology, biogeochemical cycling and hydrology of Arctic landscapes over a range of time scales. To reconstruct temporal patterns of early to late Holocene permafrost and thermokarst dynamics, site-specific palaeo-records are needed. Here we present a multi-proxy study of a 350-cm-long permafrost core from a drained lake basin on the northern Seward Peninsula, Alaska, revealing Lateglacial toHolocene thermokarst lake dynamics in a central location of Beringia. Use of radiocarbon dating, micropalaeontology (ostracods and testaceans), sedimentology (grain-size analyses, magnetic susceptibility, tephra analyses), geochemistry (total nitrogen and carbon, total organic carbon, C-13(org)) and stable water isotopes (O-18, D, dexcess) of ground ice allowed the reconstruction of several distinct thermokarst lake phases. These include a pre-lacustrine environment at the base of the core characterized by the Devil Mountain Maar tephra (22800 +/- 280cal. a BP, Unit A), which has vertically subsided in places due to subsequent development of a deep thermokarst lake that initiated around 11800cal. a BP (Unit B). At about 9000cal. a BP this lake transitioned from a stable depositional environment to a very dynamic lake system (Unit C) characterized by fluctuating lake levels, potentially intermediate wetland development, and expansion and erosion of shore deposits. Complete drainage of this lake occurred at 1060cal. a BP, including post-drainage sediment freezing from the top down to 154cm and gradual accumulation of terrestrial peat (Unit D), as well as uniform upward talik refreezing. This core-based reconstruction of multiple thermokarst lake generations since 11800cal. a BP improves our understanding of the temporal scales of thermokarst lake development from initiation to drainage, demonstrates complex landscape evolution in the ice-rich permafrost regions of Central Beringia during the Lateglacial and Holocene, and enhances our understanding of biogeochemical cycles in thermokarst-affected regions of the Arctic.
Y1  - 2016
U6  - https://doi.org/10.1111/bor.12186
SN  - 0300-9483
SN  - 1502-3885
VL  - 45
SP  - 584
EP  - 603
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Jones, Benjamin M.
A1  - Arp, Christopher D.
A1  - Whitman, Matthew S.
A1  - Nigro, Debora
A1  - Nitze, Ingmar
A1  - Beaver, John
A1  - Gadeke, Anne
A1  - Zuck, Callie
A1  - Liljedahl, Anna
A1  - Daanen, Ronald
A1  - Torvinen, Eric
A1  - Fritz, Stacey
A1  - Grosse, Guido
T1  - A lake-centric geospatial database to guide research and inform management decisions in an Arctic watershed in northern Alaska experiencing climate and land-use changes
JF  - AMBIO
N2  - Lakes are dominant and diverse landscape features in the Arctic, but conventional land cover classification schemes typically map them as a single uniform class. Here, we present a detailed lake-centric geospatial database for an Arctic watershed in northern Alaska. We developed a GIS dataset consisting of 4362 lakes that provides information on lake morphometry, hydrologic connectivity, surface area dynamics, surrounding terrestrial ecotypes, and other important conditions describing Arctic lakes. Analyzing the geospatial database relative to fish and bird survey data shows relations to lake depth and hydrologic connectivity, which are being used to guide research and aid in the management of aquatic resources in the National Petroleum Reserve in Alaska. Further development of similar geospatial databases is needed to better understand and plan for the impacts of ongoing climate and land-use changes occurring across lake-rich landscapes in the Arctic.
KW  - Arctic
KW  - Climate Change
KW  - GIS
KW  - Lakes
KW  - Land-use change
KW  - Watershed
Y1  - 2017
U6  - https://doi.org/10.1007/s13280-017-0915-9
SN  - 0044-7447
SN  - 1654-7209
VL  - 46
SP  - 769
EP  - 786
PB  - Springer
CY  - Dordrecht
ER  -