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28 records – page 1 of 3.

21st-century modeled permafrost carbon emissions accelerated by abrupt thaw beneath lakes.

https://arctichealth.org/en/permalink/ahliterature297387
Source
Nat Commun. 2018 08 15; 9(1):3262
Publication Type
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
08-15-2018
Author
Katey Walter Anthony
Thomas Schneider von Deimling
Ingmar Nitze
Steve Frolking
Abraham Emond
Ronald Daanen
Peter Anthony
Prajna Lindgren
Benjamin Jones
Guido Grosse
Author Affiliation
Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA. kmwalteranthony@alaska.edu.
Source
Nat Commun. 2018 08 15; 9(1):3262
Date
08-15-2018
Language
English
Publication Type
Journal Article
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Alaska
Carbon - chemistry
Carbon Cycle
Carbon Dioxide - chemistry
Conservation of Natural Resources - methods - trends
Freezing
Geography
Geologic Sediments - chemistry
Global warming
Lakes - chemistry
Methane - chemistry
Models, Theoretical
Permafrost - chemistry
Soil - chemistry
Abstract
Permafrost carbon feedback (PCF) modeling has focused on gradual thaw of near-surface permafrost leading to enhanced carbon dioxide and methane emissions that accelerate global climate warming. These state-of-the-art land models have yet to incorporate deeper, abrupt thaw in the PCF. Here we use model data, supported by field observations, radiocarbon dating, and remote sensing, to show that methane and carbon dioxide emissions from abrupt thaw beneath thermokarst lakes will more than double radiative forcing from circumpolar permafrost-soil carbon fluxes this century. Abrupt thaw lake emissions are similar under moderate and high representative concentration pathways (RCP4.5 and RCP8.5), but their relative contribution to the PCF is much larger under the moderate warming scenario. Abrupt thaw accelerates mobilization of deeply frozen, ancient carbon, increasing 14C-depleted permafrost soil carbon emissions by ~125-190% compared to gradual thaw alone. These findings demonstrate the need to incorporate abrupt thaw processes in earth system models for more comprehensive projection of the PCF this century.
PubMed ID
30111815 View in PubMed
Less detail

Alpine soil microbial ecology in a changing world.

https://arctichealth.org/en/permalink/ahliterature301151
Source
FEMS Microbiol Ecol. 2018 09 01; 94(9):
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Review
Date
09-01-2018
Author
Johanna Donhauser
Beat Frey
Author Affiliation
Swiss Federal Research Institute WSL, Birmensdorf, Switzerland.
Source
FEMS Microbiol Ecol. 2018 09 01; 94(9):
Date
09-01-2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Review
Keywords
Arctic Regions
Biodiversity
Climate change
Ice Cover
Permafrost - chemistry - microbiology
Soil Microbiology
Tundra
Abstract
Climate change has a disproportionally large impact on alpine soil ecosystems, leading to pronounced changes in soil microbial diversity and function associated with effects on biogeochemical processes at the local and supraregional scales. However, due to restricted accessibility, high-altitude soils remain largely understudied and a considerable heterogeneity hampers the comparability of different alpine studies. Here, we highlight differences and similarities between alpine and arctic ecosystems, and we discuss the impact of climatic variables and associated vegetation and soil properties on microbial ecology. We consider how microbial alpha-diversity, community structures and function change along altitudinal gradients and with other topographic features such as slope aspect. In addition, we focus on alpine permafrost soils, harboring a surprisingly large unknown microbial diversity and on microbial succession along glacier forefield chronosequences constituting the most thoroughly studied alpine habitat. Finally, highlighting experimental approaches, we present climate change studies showing shifts in microbial community structures and function in response to warming and altered moisture, interestingly with some contradiction. Collectively, despite harsh environmental conditions, many specially adapted microorganisms are able to thrive in alpine environments. Their community structures strongly correlate with climatic, vegetation and soil properties and thus closely mirror the complexity and small-scale heterogeneity of alpine soils.
PubMed ID
30032189 View in PubMed
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Bioclimatic gradients and soil property trends from northernmost mainland Norway to the Svalbard archipelago. Does the arctic biome extend into mainland Norway?

https://arctichealth.org/en/permalink/ahliterature304722
Source
PLoS One. 2020; 15(9):e0239183
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
2020
Author
Gauri Bandekar
Live Semb Vestgarden
Andrew Jenkins
Arvid Odland
Author Affiliation
Department of Natural Sciences and Environmental Health, Faculty of Technology, Natural Sciences and Maritime Sciences, University of South-Eastern Norway, Gullbringvegen, Bø i Telemark, Telemark, Norway.
Source
PLoS One. 2020; 15(9):e0239183
Date
2020
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Arctic Regions
Biodiversity
Climate
Islands
Norway
Permafrost - chemistry
Plant Physiological Phenomena
Plants - classification
Abstract
The boundary between the boreal and arctic biomes in northwest Europe has been a matter of debate for many years. Some authors consider that the boundary is marked by the northern limit of tree growth in the northernmost Norwegian mainland. In this study we have collected air and soil temperature data from 37 heath stands from northern Finnmark (71°N), the northernmost part of the Norwegian mainland, through Bear Island (74°N) in the Barents sea, to Adventsdalen (78)°N (in Spitsbergen) in Svalbard archipelago. In Finnmark, plots both south and north of the treeline were investigated. Vegetation and soil chemistry analyses were performed on the plots in Finnmark and Svalbard. Significant decreasing south-north trends in air and soil temperatures were observed from Finnmark to Spitsbergen. Soils in Finnmark were acidic and rich in organic matter, while those on Adventsdalen were basic and poor in organic matter. Vegetational analysis identified five communities: three in Finnmark and two on Adventsdalen. The communities in Finnmark had marked mutual similarities but were very different from those on Adventsdalen. No significant ecological differences between heaths south and north of the treeline in Finnmark were observed. Air and soil temperature variables in Finnmark were outside the recognized range for the arctic biome and inconsistent with the presence of permafrost both south and north of the treeline. A major difference between Finnmark and Spitsbergen was amount of soil frost and length of the growing season. Our results suggest that the boreal biome extends all the way to the north coast of mainland Norway; and previously used division of heaths in Finnmark into boreal, alpine and arctic biomes is not justified.
PubMed ID
32941518 View in PubMed
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Biotic responses buffer warming-induced soil organic carbon loss in Arctic tundra.

https://arctichealth.org/en/permalink/ahliterature297735
Source
Glob Chang Biol. 2018 10; 24(10):4946-4959
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Date
10-2018
Author
Junyi Liang
Jiangyang Xia
Zheng Shi
Lifen Jiang
Shuang Ma
Xingjie Lu
Marguerite Mauritz
Susan M Natali
Elaine Pegoraro
Christopher Ryan Penton
César Plaza
Verity G Salmon
Gerardo Celis
James R Cole
Konstantinos T Konstantinidis
James M Tiedje
Jizhong Zhou
Edward A G Schuur
Yiqi Luo
Author Affiliation
Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma.
Source
Glob Chang Biol. 2018 10; 24(10):4946-4959
Date
10-2018
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Keywords
Alaska
Carbon - analysis - metabolism
Climate change
Models, Theoretical
Permafrost - chemistry - microbiology
Photosynthesis
Plants - metabolism
Soil - chemistry
Soil Microbiology
Tundra
Abstract
Climate warming can result in both abiotic (e.g., permafrost thaw) and biotic (e.g., microbial functional genes) changes in Arctic tundra. Recent research has incorporated dynamic permafrost thaw in Earth system models (ESMs) and indicates that Arctic tundra could be a significant future carbon (C) source due to the enhanced decomposition of thawed deep soil C. However, warming-induced biotic changes may influence biologically related parameters and the consequent projections in ESMs. How model parameters associated with biotic responses will change under warming and to what extent these changes affect projected C budgets have not been carefully examined. In this study, we synthesized six data sets over 5 years from a soil warming experiment at the Eight Mile Lake, Alaska, into the Terrestrial ECOsystem (TECO) model with a probabilistic inversion approach. The TECO model used multiple soil layers to track dynamics of thawed soil under different treatments. Our results show that warming increased light use efficiency of vegetation photosynthesis but decreased baseline (i.e., environment-corrected) turnover rates of SOC in both the fast and slow pools in comparison with those under control. Moreover, the parameter changes generally amplified over time, suggesting processes of gradual physiological acclimation and functional gene shifts of both plants and microbes. The TECO model predicted that field warming from 2009 to 2013 resulted in cumulative C losses of 224 or 87 g/m2 , respectively, without or with changes in those parameters. Thus, warming-induced parameter changes reduced predicted soil C loss by 61%. Our study suggests that it is critical to incorporate biotic changes in ESMs to improve the model performance in predicting C dynamics in permafrost regions.
PubMed ID
29802797 View in PubMed
Less detail

Carbon accumulation in a permafrost polygon peatland: steady long-term rates in spite of shifts between dry and wet conditions.

https://arctichealth.org/en/permalink/ahliterature267243
Source
Glob Chang Biol. 2015 Feb;21(2):803-15
Publication Type
Article
Date
Feb-2015
Author
Yang Gao
John Couwenberg
Source
Glob Chang Biol. 2015 Feb;21(2):803-15
Date
Feb-2015
Language
English
Publication Type
Article
Keywords
Carbon - analysis
Climate change
Permafrost - chemistry
Seasons
Siberia
Temperature
Abstract
Ice-wedge polygon peatlands contain a substantial part of the carbon stored in permafrost soils. However, little is known about their long-term carbon accumulation rates (CAR) in relation to shifts in vegetation and climate. We collected four peat profiles from one single polygon in NE Yakutia and cut them into contiguous 0.5 cm slices. Pollen density interpolation between AMS (14)C dated levels provided the time span contained in each of the sample slices, which--in combination with the volumetric carbon content--allowed for the reconstruction of CAR over decadal and centennial timescales. Vegetation representing dry palaeo-ridges and wet depressions was reconstructed with detailed micro- and macrofossil analysis. We found repeated shifts between wet and dry conditions during the past millennium. Dry ridges with associated permafrost growth originated during phases of (relatively) warm summer temperature and collapsed during relatively cold phases, illustrating the important role of vegetation and peat as intermediaries between ambient air temperature and the permafrost. The average long-term CAR across the four profiles was 10.6 ? 5.5 g C m(-2) yr(-1). Time-weighted mean CAR did not differ significantly between wet depression and dry ridge/hummock phases (10.6 ? 5.2 g C m(-2) yr(-1) and 10.3 ? 5.7 g C m(-2) yr(-1), respectively). Although we observed increased CAR in relation to warm shifts, we also found changes in the opposite direction and the highest CAR actually occurred during the Little Ice Age. In fact, CAR rather seems to be governed by strong internal feedback mechanisms and has roughly remained stable on centennial time scales. The absence of significant differences in CAR between dry ridge and wet depression phases suggests that recent warming and associated expansion of shrubs will not affect long-term rates of carbon burial in ice-wedge polygon peatlands.
PubMed ID
25230297 View in PubMed
Less detail

Carbon monoxide photoproduction: implications for photoreactivity of Arctic permafrost-derived soil dissolved organic matter.

https://arctichealth.org/en/permalink/ahliterature267448
Source
Environ Sci Technol. 2014 Aug 19;48(16):9113-21
Publication Type
Article
Date
Aug-19-2014
Author
Jun Hong
Huixiang Xie
Laodong Guo
Guisheng Song
Source
Environ Sci Technol. 2014 Aug 19;48(16):9113-21
Date
Aug-19-2014
Language
English
Publication Type
Article
Keywords
Alaska
Arctic Regions
Carbon Monoxide - chemistry
Hydrogen-Ion Concentration
Osmolar Concentration
Permafrost - chemistry
Photochemical Processes
Rivers
Sunlight
Temperature
Abstract
Apparent quantum yields of carbon monoxide (CO) photoproduction (AQY(CO)) for permafrost-derived soil dissolved organic matter (SDOM) from the Yukon River Basin and Alaska coast were determined to examine the dependences of AQY(CO) on temperature, ionic strength, pH, and SDOM concentration. SDOM from different locations and soil depths all exhibited similar AQY(CO) spectra irrespective of soil age. AQY(CO) increased by 68% for a 20 °C warming, decreased by 25% from ionic strength 0 to 0.7 mol L(-1), and dropped by 25-38% from pH 4 to 8. These effects combined together could reduce AQY(CO) by up to 72% when SDOM transits from terrestrial environemnts to open-ocean conditions during summer in the Arctic. A Michaelis-Menten kinetics characterized the influence of SDOM dilution on AQY(CO) with a very low substrate half-saturation concentration. Generalized global-scale relationships between AQY(CO) and salinity and absorbance demostrate that the CO-based photoreactivity of ancient permaforst SDOM is comparable to that of modern riverine DOM and that the effects of the physicochemical variables revealed here alone could account for the seaward decline of AQY(CO) observed in diverse estuarine and coastal water bodies.
PubMed ID
25029258 View in PubMed
Less detail

Climate change and the permafrost carbon feedback.

https://arctichealth.org/en/permalink/ahliterature261744
Source
Nature. 2015 Apr 9;520(7546):171-9
Publication Type
Article
Date
Apr-9-2015
Author
E A G Schuur
A D McGuire
C. Schädel
G. Grosse
J W Harden
D J Hayes
G. Hugelius
C D Koven
P. Kuhry
D M Lawrence
S M Natali
D. Olefeldt
V E Romanovsky
K. Schaefer
M R Turetsky
C C Treat
J E Vonk
Source
Nature. 2015 Apr 9;520(7546):171-9
Date
Apr-9-2015
Language
English
Publication Type
Article
Keywords
Arctic Regions
Carbon Cycle
Carbon Dioxide - analysis
Climate change
Feedback
Freezing
Methane - analysis
Permafrost - chemistry
Seawater - chemistry
Uncertainty
Abstract
Large quantities of organic carbon are stored in frozen soils (permafrost) within Arctic and sub-Arctic regions. A warming climate can induce environmental changes that accelerate the microbial breakdown of organic carbon and the release of the greenhouse gases carbon dioxide and methane. This feedback can accelerate climate change, but the magnitude and timing of greenhouse gas emission from these regions and their impact on climate change remain uncertain. Here we find that current evidence suggests a gradual and prolonged release of greenhouse gas emissions in a warming climate and present a research strategy with which to target poorly understood aspects of permafrost carbon dynamics.
PubMed ID
25855454 View in PubMed
Less detail

Confocal Raman microspectroscopy reveals a convergence of the chemical composition in methanogenic archaea from a Siberian permafrost-affected soil.

https://arctichealth.org/en/permalink/ahliterature273694
Source
FEMS Microbiol Ecol. 2015 Dec;91(12)
Publication Type
Article
Date
Dec-2015
Author
Paloma Serrano
Antje Hermelink
Peter Lasch
Jean-Pierre de Vera
Nicole König
Oliver Burckhardt
Dirk Wagner
Source
FEMS Microbiol Ecol. 2015 Dec;91(12)
Date
Dec-2015
Language
English
Publication Type
Article
Keywords
Cold Temperature
DNA Restriction Enzymes - genetics
Desiccation
Euryarchaeota - chemistry - genetics - isolation & purification
Methane - biosynthesis
Microscopy, Confocal
Molecular Typing
Osmotic Pressure - physiology
Permafrost - chemistry - microbiology
Phylogeny
Radiation Tolerance - physiology
Siberia
Soil Microbiology
Spectrum Analysis, Raman
Abstract
Methanogenic archaea are widespread anaerobic microorganisms responsible for the production of biogenic methane. Several new species of psychrotolerant methanogenic archaea were recently isolated from a permafrost-affected soil in the Lena Delta (Siberia, Russia), showing an exceptional resistance against desiccation, osmotic stress, low temperatures, starvation, UV and ionizing radiation when compared to methanogens from non-permafrost environments. To gain a deeper insight into the differences observed in their resistance, we described the chemical composition of methanogenic strains from permafrost and non-permafrost environments using confocal Raman microspectroscopy (CRM). CRM is a powerful tool for microbial identification and provides fingerprint-like information about the chemical composition of the cells. Our results show that the chemical composition of methanogens from permafrost-affected soils presents a high homology and is remarkably different from strains inhabiting non-permafrost environments. In addition, we performed a phylogenetic reconstruction of the studied strains based on the functional gene mcrA to prove the different evolutionary relationship of the permafrost strains. We conclude that the permafrost methanogenic strains show a convergent chemical composition regardless of their genotype. This fact is likely to be the consequence of a complex adaptive process to the Siberian permafrost environment and might be the reason underlying their resistant nature.
PubMed ID
26499486 View in PubMed
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Ecosystem carbon response of an Arctic peatland to simulated permafrost thaw.

https://arctichealth.org/en/permalink/ahliterature300912
Source
Glob Chang Biol. 2019 05; 25(5):1746-1764
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
05-2019
Author
Carolina Voigt
Maija E Marushchak
Mikhail Mastepanov
Richard E Lamprecht
Torben R Christensen
Maxim Dorodnikov
Marcin Jackowicz-Korczynski
Amelie Lindgren
Annalea Lohila
Hannu Nykänen
Markku Oinonen
Timo Oksanen
Vesa Palonen
Claire C Treat
Pertti J Martikainen
Christina Biasi
Author Affiliation
Department of Geography, University of Montréal, Montréal, Québec, Canada.
Source
Glob Chang Biol. 2019 05; 25(5):1746-1764
Date
05-2019
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Keywords
Arctic Regions
Atmosphere - chemistry
Carbon Cycle
Carbon Dioxide - analysis - metabolism
Climate change
Greenhouse Gases - analysis - metabolism
Methane - analysis - metabolism
Oxidation-Reduction
Permafrost - chemistry
Plants - metabolism
Abstract
Permafrost peatlands are biogeochemical hot spots in the Arctic as they store vast amounts of carbon. Permafrost thaw could release part of these long-term immobile carbon stocks as the greenhouse gases (GHGs) carbon dioxide (CO2 ) and methane (CH4 ) to the atmosphere, but how much, at which time-span and as which gaseous carbon species is still highly uncertain. Here we assess the effect of permafrost thaw on GHG dynamics under different moisture and vegetation scenarios in a permafrost peatland. A novel experimental approach using intact plant-soil systems (mesocosms) allowed us to simulate permafrost thaw under near-natural conditions. We monitored GHG flux dynamics via high-resolution flow-through gas measurements, combined with detailed monitoring of soil GHG concentration dynamics, yielding insights into GHG production and consumption potential of individual soil layers. Thawing the upper 10-15 cm of permafrost under dry conditions increased CO2 emissions to the atmosphere (without vegetation: 0.74 ± 0.49 vs. 0.84 ± 0.60 g CO2 -C m-2  day-1 ; with vegetation: 1.20 ± 0.50 vs. 1.32 ± 0.60 g CO2 -C m-2  day-1 , mean ± SD, pre- and post-thaw, respectively). Radiocarbon dating (14 C) of respired CO2 , supported by an independent curve-fitting approach, showed a clear contribution (9%-27%) of old carbon to this enhanced post-thaw CO2 flux. Elevated concentrations of CO2 , CH4 , and dissolved organic carbon at depth indicated not just pulse emissions during the thawing process, but sustained decomposition and GHG production from thawed permafrost. Oxidation of CH4 in the peat column, however, prevented CH4 release to the atmosphere. Importantly, we show here that, under dry conditions, peatlands strengthen the permafrost-carbon feedback by adding to the atmospheric CO2 burden post-thaw. However, as long as the water table remains low, our results reveal a strong CH4 sink capacity in these types of Arctic ecosystems pre- and post-thaw, with the potential to compensate part of the permafrost CO2 losses over longer timescales.
PubMed ID
30681758 View in PubMed
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28 records – page 1 of 3.