TY  - JOUR
A1  - Monhonval, Arthur
A1  - Strauss, Jens
A1  - Thomas, Maxime
A1  - Hirst, Catherine
A1  - Titeux, Hugues
A1  - Louis, Justin
A1  - Gilliot, Alexia
A1  - D'Aische, Eleonore du Bois
A1  - Pereira, Benoit
A1  - Vandeuren, Aubry
A1  - Grosse, Guido
A1  - Schirrmeister, Lutz
A1  - Jongejans, Loeka Laura
A1  - Ulrich, Mathias
A1  - Opfergelt, Sophie
T1  - Thermokarst processes increase the supply of stabilizing surfaces and elements (Fe, Mn, Al, and Ca) for mineral-organic carbon interactions
JF  - Permafrost and periglacial processes
N2  - The stabilizing properties of mineral-organic carbon (OC) interactions have been studied in many soil environments (temperate soils, podzol lateritic soils, and paddy soils). Recently, interest in their role in permafrost regions is increasing as permafrost was identified as a hotspot of change. In thawing ice-rich permafrost regions, such as the Yedoma domain, 327-466 Gt of frozen OC is buried in deep sediments. Interactions between minerals and OC are important because OC is located very near the mineral matrix. Mineral surfaces and elements could mitigate recent and future greenhouse gas emissions through physical and/or physicochemical protection of OC. The dynamic changes in redox and pH conditions associated with thermokarst lake formation and drainage trigger metal-oxide dissolution and precipitation, likely influencing OC stabilization and microbial mineralization. However, the influence of thermokarst processes on mineral-OC interactions remains poorly constrained. In this study, we aim to characterize Fe, Mn, Al, and Ca minerals and their potential protective role for OC. Total and selective extractions were used to assess the crystalline and amorphous oxides or complexed metal pools as well as the organic acids found within these pools. We analyzed four sediment cores from an ice-rich permafrost area in Central Yakutia, which were drilled (i) in undisturbed Yedoma uplands, (ii) beneath a recent lake formed within Yedoma deposits, (iii) in a drained thermokarst lake basin, and (iv) beneath a mature thermokarst lake from the early Holocene period. We find a decrease in the amount of reactive Fe, Mn, Al, and Ca in the deposits on lake formation (promoting reduction reactions), and this was largely balanced by an increase in the amount of reactive metals in the deposits on lake drainage (promoting oxidation reactions). We demonstrate an increase in the metal to C molar ratio on thermokarst process, which may indicate an increase in metal-C bindings and could provide a higher protective role against microbial mineralization of organic matter. Finally, we find that an increase in mineral-OC interactions corresponded to a decrease in CO2 and CH4 gas emissions on thermokarst process. Mineral-OC interactions could mitigate greenhouse gas production from permafrost thaw as soon as lake drainage occurs.
KW  - Arctic
KW  - organic carbon stabilization
KW  - permafrost
KW  - redox processes
KW  - thaw
KW  - Yedoma
Y1  - 2022
U6  - https://doi.org/10.1002/ppp.2162
SN  - 1045-6740
SN  - 1099-1530
VL  - 33
IS  - 4
SP  - 452
EP  - 469
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Rainer, Edda M.
A1  - Seppey, Christophe Victor William
A1  - Hammer, Caroline
A1  - Svenning, Mette M.
A1  - Tveit, Alexander Tosdal
T1  - The influence of above-ground herbivory on the response of Arctic soil methanotrophs to increasing CH4 concentrations and temperatures
JF  - Microorganisms : open access journal
N2  - Rising temperatures in the Arctic affect soil microorganisms, herbivores, and peatland vegetation, thus directly and indirectly influencing microbial CH4 production. It is not currently known how methanotrophs in Arctic peat respond to combined changes in temperature, CH4 concentration, and vegetation. We studied methanotroph responses to temperature and CH4 concentration in peat exposed to herbivory and protected by exclosures. The methanotroph activity was assessed by CH4 oxidation rate measurements using peat soil microcosms and a pure culture of Methylobacter tundripaludum SV96, qPCR, and sequencing of pmoA transcripts. Elevated CH4 concentrations led to higher CH4 oxidation rates both in grazed and exclosed peat soils, but the strongest response was observed in grazed peat soils. Furthermore, the relative transcriptional activities of different methanotroph community members were affected by the CH4 concentrations. While transcriptional responses to low CH4 concentrations were more prevalent in grazed peat soils, responses to high CH4 concentrations were more prevalent in exclosed peat soils. We observed no significant methanotroph responses to increasing temperatures. We conclude that methanotroph communities in these peat soils respond to changes in the CH4 concentration depending on their previous exposure to grazing. This "conditioning " influences which strains will thrive and, therefore, determines the function of the methanotroph community.
KW  - methanotroph
KW  - methane oxidation
KW  - pmoA amplicon sequencing
KW  - Methylobacter
KW  - grazing pressure
KW  - peat soil microcosms
KW  - temperature
KW  - Arctic
Y1  - 2021
U6  - https://doi.org/10.3390/microorganisms9102080
SN  - 2076-2607
VL  - 9
IS  - 10
PB  - MDPI
CY  - Basel
ER  - 
TY  - JOUR
A1  - Mogrovejo Arias, Diana Carolina
A1  - Brill, Florian H. H.
A1  - Wagner, Dirk
T1  - Potentially pathogenic bacteria isolated from diverse habitats in Spitsbergen, Svalbard
JF  - Environmental earth sciences
N2  - The Arctic ecosystem, a reservoir of genetic microbial diversity, represents a virtually unlimited source of microorganisms that could interact with human beings. Despite continuous exploration of Arctic habitats and description of their microbial communities, bacterial phenotypes commonly associated with pathogenicity, such as hemolytic activity, have rarely been reported. In this study, samples of snow, fresh and marine water, soil, and sediment from several habitats in the Arctic archipelago of Svalbard were collected during Summer, 2017. Bacterial isolates were obtained after incubation on oligotrophic media at different temperatures and their hemolytic potential was assessed on sheep blood agar plates. Partial (alpha) or true (beta) hemolysis was observed in 32 out of 78 bacterial species. Genes expressing cytolytic compounds, such as hemolysins, likely increase the general fitness of the producing microorganisms and confer a competitive advantage over the availability of nutrients in natural habitats. In environmental species, the nutrient-acquisition function of these compounds presumably precedes their function as toxins for mammalian erythrocytes. However, in the light of global warming, the presence of hemolytic bacteria in Arctic environments highlights the possible risks associated with these microorganisms in the event of habitat melting/destruction, ecosystem transition, and re-colonization.
KW  - Arctic
KW  - Svalbard
KW  - hemolysins
KW  - climate change
KW  - pathogens
KW  - virulence
Y1  - 2020
U6  - https://doi.org/10.1007/s12665-020-8853-4
SN  - 1866-6280
SN  - 1866-6299
VL  - 79
IS  - 5
PB  - Springer
CY  - Berlin ; Heidelberg
ER  - 
TY  - JOUR
A1  - Fritz, Michael
A1  - Unkel, Ingmar
A1  - Lenz, Josefine
A1  - Gajewski, Konrad
A1  - Frenzel, Peter
A1  - Paquette, Nathalie
A1  - Lantuit, Hugues
A1  - Körte, Lisa
A1  - Wetterich, Sebastian
T1  - Regional environmental change versus local signal preservation in Holocene thermokarst lake sediments
BT  - a case study from Herschel Island, Yukon (Canada)
JF  - Journal of paleolimnolog
N2  - Thermokarst lakes cover nearly one fourth of ice-rich permafrost lowlands in the Arctic. Sediments from an athalassic subsaline thermokarst lake on Herschel Island (69°36′N; 139°04′W, Canadian Arctic) were used to understand regional changes in climate and in sediment transport, hydrology, nutrient availability and permafrost disturbance. The sediment record spans the last ~ 11,700 years and the basal date is in good agreement with the Holocene onset of thermokarst initiation in the region. Electrical conductivity in pore water continuously decreases, thus indicating desalinization and continuous increase of lake size and water level. The inc/coh ratio of XRF scans provides a high-resolution organic-carbon proxy which correlates with TOC measurements. XRF-derived Mn/Fe ratios indicate aerobic versus anaerobic conditions which moderate the preservation potential of organic matter in lake sediments. The coexistence of marine, brackish and freshwater ostracods and foraminifera is explained by (1) oligohaline to mesohaline water chemistry of the past lake and (2) redeposition of Pleistocene specimens found within upthrusted marine sediments around the lake. Episodes of catchment disturbance are identified when calcareous fossils and allochthonous material were transported into the lake by thermokarst processes such as active-layer detachments, slumping and erosion of ice-rich shores. The pollen record does not show major variations and the pollen-based climate record does not match well with other summer air temperature reconstructions from this region. Local vegetation patterns in small catchments are strongly linked to morphology and sub-surface permafrost conditions rather than to climate. Multidisciplinary studies can identify the onset and life cycle of thermokarst lakes as they play a crucial role in Arctic freshwater ecosystems and in the global carbon cycle of the past, present and future.
KW  - Arctic
KW  - Permafrost
KW  - Athalassic subsaline lake
KW  - XRF scanning
KW  - Pore-water hydrochemistry
KW  - Ostracoda
Y1  - 2018
U6  - https://doi.org/10.1007/s10933-018-0025-0
SN  - 0921-2728
SN  - 1573-0417
VL  - 60
IS  - 1
SP  - 77
EP  - 96
PB  - Springer
CY  - Dordrecht
ER  - 
TY  - JOUR
A1  - Pestryakova, Luidmila Agafyevna
A1  - Herzschuh, Ulrike
A1  - Gorodnichev, Ruslan
A1  - Wetterich, Sebastian
T1  - The sensitivity of diatom taxa from Yakutian lakes (north-eastern Siberia) to electrical conductivity and other environmental variables
JF  - Polar research : a Norwegian journal of Polar research
N2  - Relative abundances of 157 diatom taxa from Yakutian lake surface-sediments were investigated for their potential to indicate certain environmental conditions. Data from 206 sites from Arctic, sub-Arctic and boreal environments were included. Redundancy analyses were performed to assess the explanatory power of mean July temperature (T-July), conductivity, pH, dissolved silica concentration, phosphate concentration, lake depth and vegetation type on diatom species composition. Boosted regression tree analyses were performed to infer the most relevant environmental variables for abundances of individual taxa and weighted average regression was applied to infer their respective optimum and tolerance. Electrical conductivity was best indicated by diatom taxa. In contrast, only few taxa were indicative of Si and water depth. Few taxa were related to specific pH values. Although T-July, explained the highest proportion of variance in the diatom spectra and was, after conductivity, the second-most selected splitting variable, we a priori decided not to present indicator taxa because of the poorly understood relationship between diatom occurrences and T-July. In total, 92 diatom taxa were reliable indicators of a certain vegetation type or a combination of several types. The high numbers of indicative species for open vegetation sites and for forested sites suggest that the principal turnover is the transition from forest-tundra to northern taiga. Overall, our results reveal that preference ranges of diatom taxa for environmental variables are mostly broad, and the use of indicator taxa for the purposes of environmental reconstruction or environmental monitoring is therefore restricted to marked rather than subtle environmental transitions.
KW  - Temperature
KW  - pH
KW  - dissolved silica concentration
KW  - Arctic
KW  - diatom indicator species
Y1  - 2018
U6  - https://doi.org/10.1080/17518369.2018.1485625
SN  - 0800-0395
SN  - 1751-8369
VL  - 37
PB  - Routledge, Taylor & Francis Group
CY  - Abingdon
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  - 
TY  - JOUR
A1  - Ayzel, Georgy V.
T1  - Runoff predictions in ungauged arctic basins using conceptual models forced by reanalysis data
JF  - Water Resources
N2  - Due to global warming, the problem of assessing water resources and their vulnerability to climate drivers in the Arctic region has become a focus in the recent years. This study is aimed at investigating three lumped hydrological models to predict daily runoff of large-scale Arctic basins in the case of substantial data scarcity. All models were driven only by meteorological forcing reanalysis dataset without any additional information about landscape, soil, or vegetation cover properties of the studied basins. Model parameter regionalization based on transferring the whole parameter set showed good efficiency for predictions in ungauged basins. We run a blind test of the proposed methodology for ensemble runoff predictions on five sub-basins, for which only monthly observations were available, and obtained promising results for current water resources assessment for a broad domain of ungauged basins in the Russian Arctic.
KW  - hydrologic modeling
KW  - runoff
KW  - ungauged basins
KW  - reanalysis
KW  - Arctic
Y1  - 2018
U6  - https://doi.org/10.1134/S0097807818060180
SN  - 0097-8078
SN  - 1608-344X
VL  - 45
SP  - S1
EP  - S7
PB  - Pleiades Publ.
CY  - New York
ER  - 
TY  - JOUR
A1  - Engels, Stefan
A1  - Medeiros, Andrew S.
A1  - Axford, Yarrow
A1  - Brooks, Steve
A1  - Heiri, Oliver
A1  - Luoto, Tomi P.
A1  - Nazarova, Larisa B.
A1  - Porinchu, David F.
A1  - Quinlan, Roberto
A1  - Self, Angela E.
T1  - Temperature change as a driver of spatial patterns and long-term trends in chironomid (Insecta: Diptera) diversity
JF  - Global change biology
N2  - Anthropogenic activities have led to a global decline in biodiversity, and monitoring studies indicate that both insect communities and wetland ecosystems are particularly affected. However, there is a need for long-term data (over centennial or millennial timescales) to better understand natural community dynamics and the processes that govern the observed trends. Chironomids (Insecta: Diptera: Chironomidae) are often the most abundant insects in lake ecosystems, sensitive to environmental change, and, because their larval exoskeleton head capsules preserve well in lake sediments, they provide a unique record of insect community dynamics through time. Here, we provide the results of a metadata analysis of chironomid diversity across a range of spatial and temporal scales. First, we analyse spatial trends in chironomid diversity using Northern Hemispheric data sets overall consisting of 837 lakes. Our results indicate that in most of our data sets, summer temperature (T-jul) is strongly associated with spatial trends in modern-day chironomid diversity. We observe a strong increase in chironomid alpha diversity with increasing T-jul in regions with present-day T-jul between 2.5 and 14 degrees C. In some areas with T-jul > 14 degrees C, chironomid diversity stabilizes or declines. Second, we demonstrate that the direction and amplitude of change in alpha diversity in a compilation of subfossil chironomid records spanning the last glacial-interglacial transition (similar to 15,000-11,000 years ago) are similar to those observed in our modern data. A compilation of Holocene records shows that during phases when the amplitude of temperature change was small, site-specific factors had a greater influence on the chironomid fauna obscuring the chironomid diversity-temperature relationship. Our results imply expected overall chironomid diversity increases in colder regions such as the Arctic under sustained global warming, but with complex and not necessarily predictable responses for individual sites.
KW  - Arctic
KW  - biodiversity
KW  - climate warming
KW  - freshwater ecosystems
KW  - insects
KW  - palaeoecology
KW  - Quaternary
Y1  - 2019
U6  - https://doi.org/10.1111/gcb.14862
SN  - 1354-1013
SN  - 1365-2486
VL  - 26
IS  - 3
SP  - 1155
EP  - 1169
PB  - Wiley
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Strätling, Susanne
T1  - The Author as Researcher
BT  - Boris Pil’niak Samples the Arctic Sea
JF  - Russian Literature
N2  - This article proposes a new perspective on avant-garde travel writing through the lens of scientific field work, investigating these new writing techniques in Boris Pil’niak’s expedition prose. In the 1920s, the researching writer represents a hidden, but influential counterpart to the widely propagated figure of the working writer. While the author as producer combines word and deed in an operative act, the author as researcher investigates the production of knowledge. This entails revising the centrality of facts. Literature as artistic research subverts factography by going beyond the horizons of veristic data registration to include uncharted realms and vague possibilities. This exploration leads to specific genres: the author as researcher tries his hand at a kind of laboratory text, a prolific genre at the intersection of testing equipment, recording media, and hypothetical thought. Not confined to a sterile lab, avant-garde writer-researchers, as members of research expeditions, oscillate between their home writing desks and the remote depths of the emerging USSR. At the same time, they explore writing practices situated between data acquisition, sampling, fact-finding, observation and recording.
KW  - Arctic
Y1  - 2019
U6  - https://doi.org/10.1016/j.ruslit.2019.04.012
SN  - 0304-3479
SN  - 1878-3678
VL  - 103
SP  - 283
EP  - 303
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Ramage, Justine Lucille
A1  - Irrgang, Anna Maria
A1  - Herzschuh, Ulrike
A1  - Morgenstern, Anne
A1  - Couture, Nicole
A1  - Lantuit, Hugues
T1  - Terrain controls on the occurrence of coastal retrogressive thaw slumps along the Yukon Coast, Canada
JF  - Journal of geophysical research : Earth surface
N2  - Retrogressive thaw slumps (RTSs) are among the most active landforms in the Arctic; their number has increased significantly over the past decades. While processes initiating discrete RTSs are well identified, the major terrain controls on the development of coastal RTSs at a regional scale are not yet defined. Our research reveals the main geomorphic factors that determine the development of RTSs along a 238km segment of the Yukon Coast, Canada. We (1) show the current extent of RTSs, (2) ascertain the factors controlling their activity and initiation, and (3) explain the spatial differences in the density and areal coverage of RTSs. We mapped and classified 287 RTSs using high-resolution satellite images acquired in 2011. We highlighted the main terrain controls over their development using univariate regression trees model. Coastal geomorphology influenced both the activity and initiation of RTSs: active RTSs and RTSs initiated after 1972 occurred primarily on terrains with slope angles greater than 3.9 degrees and 5.9 degrees, respectively. The density and areal coverage of RTSs were constrained by the volume and thickness of massive ice bodies. Differences in rates of coastal change along the coast did not affect the model. We infer that rates of coastal change averaged over a 39year period are unable to reflect the complex relationship between RTSs and coastline dynamics. We emphasize the need for large-scale studies of RTSs to evaluate their impact on the ecosystem and to measure their contribution to the global carbon budget. Plain Language Summary Retrogressive thaw slumps, henceforth slumps are a type of landslides that occur when permafrost thaws. Slumps are active landforms: they develop quickly and extend over several hectares. Satellite imagery allows to map such slumps over large areas. Our research shows where slumps develop along a 238 km segment of the Yukon Coast in Canada and explains which environments are most suitable for slump occurrence. We found that active and newly developed slumps were triggered where coastal slopes were greater than 3.9 degrees and 5.9 degrees, respectively. We explain that coastal erosion influences the development of slumps by modifying coastal slopes. We found that the highest density of slumps as well as the largest slumps occurred on terrains with high amounts of ice bodies in the ground. This study provides tools to better identify areas in the Arctic that are prone to slump development.
KW  - permafrost degradation
KW  - retrogressive thaw slumps
KW  - coastal erosion
KW  - Arctic
KW  - coastal geomorphology
Y1  - 2017
U6  - https://doi.org/10.1002/2017JF004231
SN  - 2169-9003
SN  - 2169-9011
VL  - 122
SP  - 1619
EP  - 1634
PB  - American Geophysical Union
CY  - Washington
ER  - 
TY  - JOUR
A1  - Strauss, Jens
A1  - Schirrmeister, Lutz
A1  - Grosse, Guido
A1  - Fortier, Daniel
A1  - Hugelius, Gustaf
A1  - Knoblauch, Christian
A1  - Romanovsky, Vladimir E.
A1  - Schadel, Christina
A1  - von Deimling, Thomas Schneider
A1  - Schuur, Edward A. G.
A1  - Shmelev, Denis
A1  - Ulrich, Mathias
A1  - Veremeeva, Alexandra
T1  - Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability
JF  - Earth science reviews : the international geological journal bridging the gap between research articles and textbooks
N2  - Permafrost is a distinct feature of the terrestrial Arctic and is vulnerable to climate warming. Permafrost degrades in different ways, including deepening of a seasonally unfrozen surface and localized but rapid development of deep thaw features. Pleistocene ice-rich permafrost with syngenetic ice-wedges, termed Yedoma deposits, are widespread in Siberia, Alaska, and Yukon, Canada and may be especially prone to rapid-thaw processes. Freeze-locked organic matter in such deposits can be re-mobilized on short time-scales and contribute to a carbon-cycle climate feedback. Here we synthesize the characteristics and vulnerability of Yedoma deposits by synthesizing studies on the Yedoma origin and the associated organic carbon pool. We suggest that Yedoma deposits accumulated under periglacial weathering, transport, and deposition dynamics in non-glaciated regions during the late Pleistocene until the beginning of late glacial warming. The deposits formed due to a combination of aeolian, colluvial, nival, and alluvial deposition and simultaneous ground ice accumulation. We found up to 130 gigatons organic carbon in Yedoma, parts of which are well-preserved and available for fast decomposition after thaw. Based on incubation experiments, up to 10% of the Yedoma carbon is considered especially decomposable and may be released upon thaw. The substantial amount of ground ice in Yedoma makes it highly vulnerable to disturbances such as thermokarst and thermo-erosion processes. Mobilization of permafrost carbon is expected to increase under future climate warming. Our synthesis results underline the need of accounting for Yedoma carbon stocks in next generation Earth-System-Models for a more complete representation of the permafrost-carbon feedback.
KW  - Perennial frozen ground
KW  - Thermokarst
KW  - Arctic
KW  - Late Pleistocene
KW  - Greenhouse gas source
KW  - Climate feedback
Y1  - 2017
U6  - https://doi.org/10.1016/j.earscirev.2017.07.007
SN  - 0012-8252
SN  - 1872-6828
VL  - 172
SP  - 75
EP  - 86
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Radosavljevic, Boris
A1  - Lantuit, Hugues
A1  - Pollard, Wayne
A1  - Overduin, Pier Paul
A1  - Couture, Nicole
A1  - Sachs, Torsten
A1  - Helm, Veit
A1  - Fritz, Michael
T1  - Erosion and Flooding-Threats to Coastal Infrastructure in the Arctic: A Case Study from Herschel Island, Yukon Territory, Canada
JF  - Estuaries and coasts : journal of the Estuarine Research Federation
N2  - Arctic coastal infrastructure and cultural and archeological sites are increasingly vulnerable to erosion and flooding due to amplified warming of the Arctic, sea level rise, lengthening of open water periods, and a predicted increase in frequency of major storms. Mitigating these hazards necessitates decision-making tools at an appropriate scale. The objectives of this paper are to provide such a tool by assessing potential erosion and flood hazards at Herschel Island, a UNESCO World Heritage candidate site. This study focused on Simpson Point and the adjacent coastal sections because of their archeological, historical, and cultural significance. Shoreline movement was analyzed using the Digital Shoreline Analysis System (DSAS) after digitizing shorelines from 1952, 1970, 2000, and 2011. For purposes of this analysis, the coast was divided in seven coastal reaches (CRs) reflecting different morphologies and/or exposures. Using linear regression rates obtained from these data, projections of shoreline position were made for 20 and 50 years into the future. Flood hazard was assessed using a least cost path analysis based on a high-resolution light detection and ranging (LiDAR) dataset and current Intergovernmental Panel on Climate Change sea level estimates. Widespread erosion characterizes the study area. The rate of shoreline movement in different periods of the study ranges from -5.5 to 2.7 mI double dagger a(-1) (mean -0.6 mI double dagger a(-1)). Mean coastal retreat decreased from -0.6 mI double dagger a(-1) to -0.5 mI double dagger a(-1), for 1952-1970 and 1970-2000, respectively, and increased to -1.3 mI double dagger a(-1) in the period 2000-2011. Ice-rich coastal sections most exposed to wave attack exhibited the highest rates of coastal retreat. The geohazard map combines shoreline projections and flood hazard analyses to show that most of the spit area has extreme or very high flood hazard potential, and some buildings are vulnerable to coastal erosion. This study demonstrates that transgressive forcing may provide ample sediment for the expansion of depositional landforms, while growing more susceptible to overwash and flooding.
KW  - Arctic
KW  - Coastal erosion
KW  - UNESCO
KW  - Vulnerability mapping
KW  - Permafrost coasts
Y1  - 2016
U6  - https://doi.org/10.1007/s12237-015-0046-0
SN  - 1559-2723
SN  - 1559-2731
VL  - 39
SP  - 900
EP  - 915
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Tanski, George
A1  - Couture, Nicole
A1  - Lantuit, Hugues
A1  - Eulenburg, Antje
A1  - Fritz, Michael
T1  - Eroding permafrost coasts release low amounts of dissolved organic carbon (DOC) from ground ice into the nearshore zone of the Arctic Ocean
JF  - Global biogeochemical cycles
N2  - Ice-rich permafrost coasts in the Arctic are highly sensitive to climate warming and erode at a pace that exceeds the global average. Permafrost coasts deliver vast amounts of organic carbon into the nearshore zone of the Arctic Ocean. Numbers on flux exist for particulate organic carbon (POC) and total or soil organic carbon (TOC, SOC). However, they do not exist for dissolved organic carbon (DOC), which is known to be highly bioavailable. This study aims to estimate DOC stocks in coastal permafrost as well as the annual flux into the ocean. DOC concentrations in ground ice were analyzed along the ice-rich Yukon coast (YC) in the western Canadian Arctic. The annual DOC flux was estimated using available numbers for coast length, cliff height, annual erosion rate, and volumetric ice content in different stratigraphic horizons. Our results showed that DOC concentrations in ground ice range between 0.3 and 347.0mgL(-1) with an estimated stock of 13.63.0gm(-3) along the YC. An annual DOC flux of 54.90.9Mgyr(-1) was computed. These DOC fluxes are low compared to POC and SOC fluxes from coastal erosion or POC and DOC fluxes from Arctic rivers. We conclude that DOC fluxes from permafrost coasts play a secondary role in the Arctic carbon budget. However, this DOC is assumed to be highly bioavailable. We hypothesize that DOC from coastal erosion is important for ecosystems in the Arctic nearshore zones, particularly in summer when river discharge is low, and in areas where rivers are absent.
KW  - Arctic
KW  - permafrost
KW  - coastal erosion
KW  - biogeochemistry
KW  - carbon cycle
Y1  - 2016
U6  - https://doi.org/10.1002/2015GB005337
SN  - 0886-6236
SN  - 1944-9224
VL  - 30
SP  - 1054
EP  - 1068
PB  - American Geophysical Union
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Fritz, Michael
A1  - Wolter, Juliane
A1  - Rudaya, Natalia
A1  - Palagushkina, Olga
A1  - Nazarova, Larisa B.
A1  - Obu, Jaroslav
A1  - Rethemeyer, Janet
A1  - Lantuit, Hugues
A1  - Wetterich, Sebastian
T1  - Holocene ice-wedge polygon development in northern Yukon permafrost peatlands (Canada)
JF  - Quaternary science reviews : the international multidisciplinary research and review journal
N2  - Ice-wedge polygon (IWP) peatlands in the Arctic and Subarctic are extremely vulnerable to climatic and environmental change. We present the results of a multidisciplinary paleoenvironmental study on IWPs in the northern Yukon, Canada. High-resolution laboratory analyses were carried out on a permafrost core and the overlying seasonally thawed (active) layer, from an IWP located in a drained lake basin on Herschel Island. In relation to 14 Accelerator Mass Spectrometry (AMS) radiocarbon dates spanning the last 5000 years, we report sedimentary data including grain size distribution and biogeochemical parameters (organic carbon, nitrogen, C/N ratio, delta C-13), stable water isotopes (delta O-18, delta D), as well as fossil pollen, plant macrofossil and diatom assemblages. Three sediment units (SUS) correspond to the main stages of deposition (1) in a thermokarst lake (SW : 4950 to 3950 cal yrs BP), (2) during transition from lacustrine to palustrine conditions after lake drainage (SU2: 3950 to 3120 cal yrs BP), and (3) in palustrine conditions of the IWP field that developed after drainage (SU3: 3120 cal yrs BP to 2012 CE). The lacustrine phase (pre 3950 cal yrs BP) is characterized by planktonic-benthic and pioneer diatom species indicating circumneutral waters, and very few plant macrofossils. The pollen record has captured a regional signal of relatively stable vegetation composition and climate for the lacustrine stage of the record until 3950 cal yrs BP. Palustrine conditions with benthic and acidophilic diatom species characterize the peaty shallow-water environments of the low-centered IWP. The transition from lacustrine to palustrine conditions was accompanied by acidification and rapid revegetation of the lake bottom within about 100 years. Since the palustrine phase we consider the pollen record as a local vegetation proxy dominated by the plant communities growing in the IWP. Ice-wedge cracking in water-saturated sediments started immediately after lake drainage at about 3950 cal yrs BP and led to the formation of an IWP mire. Permafrost aggradation through downward closed-system freezing of the lake talik is indicated by the stable water isotope record. The originally submerged IWP center underwent gradual drying during the past 2000 years. This study highlights the sensitivity of permafrost landscapes to climate and environmental change throughout the Holocene. (C) 2016 Elsevier Ltd. All rights reserved.
KW  - Permafrost peatlands
KW  - Arctic
KW  - Thermokarst
KW  - Talik
KW  - Ice-wedge polygon
KW  - Pollen
KW  - Diatoms
KW  - Plant macrofossils
KW  - Stable water isotopes
KW  - Deuterium excess
Y1  - 2016
U6  - https://doi.org/10.1016/j.quascirev.2016.02.008
SN  - 0277-3791
VL  - 147
SP  - 279
EP  - 297
PB  - Elsevier
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Hoffmann, Anne
A1  - Osterloh, Lukas
A1  - Stone, Robert
A1  - Lampert, Astrid
A1  - Ritter, Christoph
A1  - Stock, Maria
A1  - Tunved, Peter
A1  - Hennig, Tabea
A1  - Böckmann, Christine
A1  - Li, Shao-Meng
A1  - Eleftheriadis, Kostas
A1  - Maturilli, Marion
A1  - Orgis, Thomas
A1  - Herber, Andreas
A1  - Neuber, Roland
A1  - Dethloff, Klaus
T1  - Remote sensing and in-situ measurements of tropospheric aerosol, a PAMARCMiP case study
JF  - Atmospheric environment : air pollution ; emissions, transport and dispersion, transformation, deposition effects, micrometeorology, urban atmosphere, global atmosphere
N2  - In this work, a closure experiment for tropospheric aerosol is presented. Aerosol size distributions and single scattering albedo from remote sensing data are compared to those measured in-situ. An aerosol pollution event on 4 April 2009 was observed by ground based and airborne lidar and photometer in and around Ny-Alesund, Spitsbergen, as well as by DMPS, nephelometer and particle soot absorption photometer at the nearby Zeppelin Mountain Research Station.
 The presented measurements were conducted in an area of 40 x 20 km around Ny-Alesund as part of the 2009 Polar Airborne Measurements and Arctic Regional Climate Model Simulation Project (PAMARCMiP). Aerosol mainly in the accumulation mode was found in the lower troposphere, however, enhanced backscattering was observed up to the tropopause altitude. A comparison of meteorological data available at different locations reveals a stable multi-layer-structure of the lower troposphere. It is followed by the retrieval of optical and microphysical aerosol parameters. Extinction values have been derived using two different methods, and it was found that extinction (especially in the UV) derived from Raman lidar data significantly surpasses the extinction derived from photometer AOD profiles. Airborne lidar data shows volume depolarization values to be less than 2.5% between 500 m and 2.5 km altitude, hence, particles in this range can be assumed to be of spherical shape. In-situ particle number concentrations measured at the Zeppelin Mountain Research Station at 474 m altitude peak at about 0.18 mu m diameter, which was also found for the microphysical inversion calculations performed at 850 m and 1500 m altitude. Number concentrations depend on the assumed extinction values, and slightly decrease with altitude as well as the effective particle diameter. A low imaginary part in the derived refractive index suggests weakly absorbing aerosols, which is confirmed by low black carbon concentrations, measured at the Zeppelin Mountain as well as on board the Polar 5 aircraft.
KW  - Arctic
KW  - Aerosols
KW  - Lidar
KW  - Arctic haze
Y1  - 2012
U6  - https://doi.org/10.1016/j.atmosenv.2011.11.027
SN  - 1352-2310
VL  - 52
IS  - 3
SP  - 56
EP  - 66
PB  - Elsevier
CY  - Oxford
ER  -