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Kumar A, Chaudhary A, Agrahari B, Chaudhary K, Kumar P, Singh RG. Concurrent Cu(II)-initiated Fenton-like reaction and glutathione depletion to escalate chemodynamic therapy. Chem Commun (Camb) 2023; 59:14305-14308. [PMID: 37970743 DOI: 10.1039/d3cc04519f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Chemodynamic therapy is an evolving therapeutic strategy but there are certain limitations associated with its treatment. Herein, we present de novo synthesis and mechanistic evaluation of HL1-HL8 ligands and their corresponding CuII(L1)2-CuII(L8)2. The most active Cu(L2)2 (IC50 = 5.3 μM, MCF-7) complex exclusively depletes glutathione while simultaneously promoting ROS production. Cu(L2)2 also affects other macromolecules like the mitochondrial membrane and DNA while activating the unfolded protein response cascade.
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Affiliation(s)
- Ashwini Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India.
| | - Ayushi Chaudhary
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India.
| | - Bhumika Agrahari
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India.
| | - Kajal Chaudhary
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India.
| | - Pooran Kumar
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India.
| | - Ritika Gautam Singh
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh 208016, India.
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2
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Chen Y, Cheng X, Liu A, Chen Q, Wang C. Tracking lake drainage events and drained lake basin vegetation dynamics across the Arctic. Nat Commun 2023; 14:7359. [PMID: 37968270 PMCID: PMC10652023 DOI: 10.1038/s41467-023-43207-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 11/03/2023] [Indexed: 11/17/2023] Open
Abstract
Widespread lake drainage can lead to large-scale drying in Arctic lake-rich areas, affecting hydrology, ecosystems and permafrost carbon dynamics. To date, the spatio-temporal distribution, driving factors, and post-drainage dynamics of lake drainage events across the Arctic remain unclear. Using satellite remote sensing and surface water products, we identify over 35,000 (~0.6% of all lakes) lake drainage events in the northern permafrost zone between 1984 and 2020, with approximately half being relatively understudied non-thermokarst lakes. Smaller, thermokarst, and discontinuous permafrost area lakes are more susceptible to drainage compared to their larger, non-thermokarst, and continuous permafrost area counterparts. Over time, discontinuous permafrost areas contribute more drained lakes annually than continuous permafrost areas. Following drainage, vegetation rapidly colonizes drained lake basins, with thermokarst drained lake basins showing significantly higher vegetation growth rates and greenness levels than their non-thermokarst counterparts. Under warming, drained lake basins are likely to become more prevalent and serve as greening hotspots, playing an important role in shaping Arctic ecosystems.
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Affiliation(s)
- Yating Chen
- College of Geography and Environment, Shandong Normal University, Jinan, 250014, China.
- Key Laboratory of Comprehensive Observation of Polar Environment (Sun Yat-sen University), Ministry of Education, Zhuhai, 519082, China.
- College of Global Change and Earth System Science, Beijing Normal University, 100875, Beijing, China.
| | - Xiao Cheng
- Key Laboratory of Comprehensive Observation of Polar Environment (Sun Yat-sen University), Ministry of Education, Zhuhai, 519082, China.
- School of Geospatial Engineering and Science, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, 519082, China.
| | - Aobo Liu
- College of Geography and Environment, Shandong Normal University, Jinan, 250014, China.
- Key Laboratory of Comprehensive Observation of Polar Environment (Sun Yat-sen University), Ministry of Education, Zhuhai, 519082, China.
- College of Global Change and Earth System Science, Beijing Normal University, 100875, Beijing, China.
| | - Qingfeng Chen
- College of Geography and Environment, Shandong Normal University, Jinan, 250014, China
| | - Chengxin Wang
- College of Geography and Environment, Shandong Normal University, Jinan, 250014, China
- Key Research Institute of Yellow River Civilization and Sustainable Development & Yellow River Civilization by Provincial and Ministerial Co-construction of Collaborative Innovation Center, Henan University, Kaifeng, 475001, China
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3
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Yang S, Anthony SE, Jenrich M, In 't Zandt MH, Strauss J, Overduin PP, Grosse G, Angelopoulos M, Biskaborn BK, Grigoriev MN, Wagner D, Knoblauch C, Jaeschke A, Rethemeyer J, Kallmeyer J, Liebner S. Microbial methane cycling in sediments of Arctic thermokarst lagoons. GLOBAL CHANGE BIOLOGY 2023; 29:2714-2731. [PMID: 36811358 DOI: 10.1111/gcb.16649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 01/27/2023] [Indexed: 05/31/2023]
Abstract
Thermokarst lagoons represent the transition state from a freshwater lacustrine to a marine environment, and receive little attention regarding their role for greenhouse gas production and release in Arctic permafrost landscapes. We studied the fate of methane (CH4 ) in sediments of a thermokarst lagoon in comparison to two thermokarst lakes on the Bykovsky Peninsula in northeastern Siberia through the analysis of sediment CH4 concentrations and isotopic signature, methane-cycling microbial taxa, sediment geochemistry, lipid biomarkers, and network analysis. We assessed how differences in geochemistry between thermokarst lakes and thermokarst lagoons, caused by the infiltration of sulfate-rich marine water, altered the microbial methane-cycling community. Anaerobic sulfate-reducing ANME-2a/2b methanotrophs dominated the sulfate-rich sediments of the lagoon despite its known seasonal alternation between brackish and freshwater inflow and low sulfate concentrations compared to the usual marine ANME habitat. Non-competitive methylotrophic methanogens dominated the methanogenic community of the lakes and the lagoon, independent of differences in porewater chemistry and depth. This potentially contributed to the high CH4 concentrations observed in all sulfate-poor sediments. CH4 concentrations in the freshwater-influenced sediments averaged 1.34 ± 0.98 μmol g-1 , with highly depleted δ13 C-CH4 values ranging from -89‰ to -70‰. In contrast, the sulfate-affected upper 300 cm of the lagoon exhibited low average CH4 concentrations of 0.011 ± 0.005 μmol g-1 with comparatively enriched δ13 C-CH4 values of -54‰ to -37‰ pointing to substantial methane oxidation. Our study shows that lagoon formation specifically supports methane oxidizers and methane oxidation through changes in pore water chemistry, especially sulfate, while methanogens are similar to lake conditions.
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Affiliation(s)
- Sizhong Yang
- GFZ German Research Center for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Potsdam, Germany
- Cryosphere Research Station on the Qinghai-Tibet Plateau, State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China
| | - Sara E Anthony
- Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany
| | - Maren Jenrich
- Permafrost Research Section, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
- Institute of Geosciences, University of Potsdam, Potsdam, Germany
| | - Michiel H In 't Zandt
- Department of Microbiology, RIBES, Radboud University, Nijmegen, the Netherlands
- Netherlands Earth System Science Center, Utrecht University, Utrecht, the Netherlands
| | - Jens Strauss
- Permafrost Research Section, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
| | - Pier Paul Overduin
- Permafrost Research Section, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
| | - Guido Grosse
- Permafrost Research Section, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
- Institute of Geosciences, University of Potsdam, Potsdam, Germany
| | - Michael Angelopoulos
- Permafrost Research Section, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
| | - Boris K Biskaborn
- Polar Terrestrial Environmental Systems Section, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Potsdam, Germany
| | - Mikhail N Grigoriev
- Laboratory of General Geocryology, Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Yakutsk, Russia
| | - Dirk Wagner
- GFZ German Research Center for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Potsdam, Germany
- Institute of Geosciences, University of Potsdam, Potsdam, Germany
| | - Christian Knoblauch
- Institute of Soil Science, Universität Hamburg, Hamburg, Germany
- Center for Earth System Research and Sustainability, Universität Hamburg, Hamburg, Germany
| | - Andrea Jaeschke
- Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany
| | - Janet Rethemeyer
- Institute of Geology and Mineralogy, University of Cologne, Cologne, Germany
| | - Jens Kallmeyer
- GFZ German Research Center for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Potsdam, Germany
| | - Susanne Liebner
- GFZ German Research Center for Geosciences, Helmholtz Centre Potsdam, Section Geomicrobiology, Potsdam, Germany
- Institute of Biochemistry and Biology, University of Potsdam, Potsdam, Germany
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4
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Glückler R, Geng R, Grimm L, Baisheva I, Herzschuh U, Stoof-Leichsenring KR, Kruse S, Andreev A, Pestryakova L, Dietze E. Holocene wildfire and vegetation dynamics in Central Yakutia, Siberia, reconstructed from lake-sediment proxies. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.962906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Wildfires play an essential role in the ecology of boreal forests. In eastern Siberia, fire activity has been increasing in recent years, challenging the livelihoods of local communities. Intensifying fire regimes also increase disturbance pressure on the boreal forests, which currently protect the permafrost beneath from accelerated degradation. However, long-term relationships between changes in fire regime and forest structure remain largely unknown. We assess past fire-vegetation feedbacks using sedimentary proxy records from Lake Satagay, Central Yakutia, Siberia, covering the past c. 10,800 years. Results from macroscopic and microscopic charcoal analyses indicate high amounts of burnt biomass during the Early Holocene, and that the present-day, low-severity surface fire regime has been in place since c. 4,500 years before present. A pollen-based quantitative reconstruction of vegetation cover and a terrestrial plant record based on sedimentary ancient DNA metabarcoding suggest a pronounced shift in forest structure toward the Late Holocene. Whereas the Early Holocene was characterized by postglacial open larch-birch woodlands, forest structure changed toward the modern, mixed larch-dominated closed-canopy forest during the Mid-Holocene. We propose a potential relationship between open woodlands and high amounts of burnt biomass, as well as a mediating effect of dense larch forest on the climate-driven intensification of fire regimes. Considering the anticipated increase in forest disturbances (droughts, insect invasions, and wildfires), higher tree mortality may force the modern state of the forest to shift toward an open woodland state comparable to the Early Holocene. Such a shift in forest structure may result in a positive feedback on currently intensifying wildfires. These new long-term data improve our understanding of millennial-scale fire regime changes and their relationships to changes of vegetation in Central Yakutia, where the local population is already being confronted with intensifying wildfire seasons.
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Abstract
Under a warming climate, permafrost degradation has resulted in profound hydrogeological consequences. Here, we mainly review 240 recent relevant papers. Permafrost degradation has boosted groundwater storage and discharge to surface runoffs through improving hydraulic connectivity and reactivation of groundwater flow systems, resulting in reduced summer peaks, delayed autumn flow peaks, flattened annual hydrographs, and deepening and elongating flow paths. As a result of permafrost degradation, lowlands underlain by more continuous, colder, and thicker permafrost are getting wetter and uplands and mountain slopes, drier. However, additional contribution of melting ground ice to groundwater and stream-flows seems limited in most permafrost basins. As a result of permafrost degradation, the permafrost table and supra-permafrost water table are lowering; subaerial supra-permafrost taliks are forming; taliks are connecting and expanding; thermokarst activities are intensifying. These processes may profoundly impact on ecosystem structures and functions, terrestrial processes, surface and subsurface coupled flow systems, engineered infrastructures, and socioeconomic development. During the last 20 years, substantial and rapid progress has been made in many aspects in cryo-hydrogeology. However, these studies are still inadequate in desired spatiotemporal resolutions, multi-source data assimilation and integration, as well as cryo-hydrogeological modeling, particularly over rugged terrains in ice-rich, warm (>−1 °C) permafrost zones. Future research should be prioritized to the following aspects. First, we should better understand the concordant changes in processes, mechanisms, and trends for terrestrial processes, hydrometeorology, geocryology, hydrogeology, and ecohydrology in warm and thin permafrost regions. Second, we should aim towards revealing the physical and chemical mechanisms for the coupled processes of heat transfer and moisture migration in the vadose zone and expanding supra-permafrost taliks, towards the coupling of the hydrothermal dynamics of supra-, intra- and sub-permafrost waters, as well as that of water-resource changes and of hydrochemical and biogeochemical mechanisms for the coupled movements of solutes and pollutants in surface and subsurface waters as induced by warming and thawing permafrost. Third, we urgently need to establish and improve coupled predictive distributed cryo-hydrogeology models with optimized parameterization. In addition, we should also emphasize automatically, intelligently, and systematically monitoring, predicting, evaluating, and adapting to hydrogeological impacts from degrading permafrost at desired spatiotemporal scales. Systematic, in-depth, and predictive studies on and abilities for the hydrogeological impacts from degrading permafrost can greatly advance geocryology, cryo-hydrogeology, and cryo-ecohydrology and help better manage water, ecosystems, and land resources in permafrost regions in an adaptive and sustainable manner.
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6
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Walraevens K, Fernández-Lagunas A, Blaser P, Aeschbach W, Vandenbohede A, Van Camp M. Understanding the mechanisms of groundwater recharge and flow in periglacial environments: New insights from the Ledo-Paniselian aquifer in Belgium. JOURNAL OF CONTAMINANT HYDROLOGY 2021; 241:103819. [PMID: 33989899 DOI: 10.1016/j.jconhyd.2021.103819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 03/31/2021] [Accepted: 05/03/2021] [Indexed: 06/12/2023]
Abstract
The Ledo-Paniselian aquifer in Belgium has been proposed to offer unique opportunities to study groundwater recharge and flow in periglacial conditions during the Last Glacial Maximum (LGM), due to its location in the permanent permafrost area, south of the ice sheet at that time. A palaeoclimatic record had been set up previously for this aquifer, consisting of major ion chemistry, stable isotopes, radiocarbon and noble gases. In this paper, methane data have been used to further refine the paleoclimatic model, along with revisiting in detail the set of chemical data, focusing on the area where groundwaters, recharged around the LGM, are known to occur. It was found that the high methane concentrations corroborate the hypothesis of groundwater recharge taking place during permafrost melting, from methane-bubbling lakes that had developed to the south of an eolian sand ridge. A relict flow path, existing in the aquifer during some period as permafrost was thawing, has been established, starting from these temporary recharge areas, based on various chemical parameters, radiocarbon model ages and noble gas recharge temperatures.
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Affiliation(s)
- Kristine Walraevens
- Laboratory for Applied Geology and Hydrogeology, Department of Geology, Ghent University, Krijgslaan 281-S8, B-9000 Gent, Belgium.
| | - Albert Fernández-Lagunas
- Laboratory for Applied Geology and Hydrogeology, Department of Geology, Ghent University, Krijgslaan 281-S8, B-9000 Gent, Belgium
| | - Petra Blaser
- petraconsult, Gersau, Renggstrasse 17, CH 6442 Gersau, Switzerland
| | - Werner Aeschbach
- Institut für Umweltphysik, Universität Heidelberg, D-69120 Heidelberg, Germany; Heidelberg Center for the Environment, Universität Heidelberg, D-69120 Heidelberg, Germany
| | | | - Marc Van Camp
- Laboratory for Applied Geology and Hydrogeology, Department of Geology, Ghent University, Krijgslaan 281-S8, B-9000 Gent, Belgium
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Kut AA, Woronko B, Spektor VV, Klimova IV. Grain-surface microtextures in deposits affected by periglacial conditions (Abalakh High-Accumulation Plain, Central Yakutia, Russia). Micron 2021; 146:103067. [PMID: 33940345 DOI: 10.1016/j.micron.2021.103067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 03/31/2021] [Accepted: 03/31/2021] [Indexed: 11/28/2022]
Abstract
Our paper describes and interprets grain microtexture and microstructure collected from periglacial sediments on the Abalakh High-Accumulation Plain (AHAP) in Central Yakutia. This territory occupies the Lena-Amga Rivers interfluve. In borehole 18/1, five sediment Complexes (I-V) of successive environments were recognized: 1) alluvial in the base of the borehole-Complex I; 2) alluvial-lake-Complex II; 3) lake-complex-Complex III; 4) ice-complex (yedoma)-Complex IV; and finally 5) a Holocene cover-Complex V. Quartz sand-grain and silt-grain microtextural analysis was undertaken in a scanning electron microscope (SEM) and supplemented by mineralogical analyses to reconstruct the sedimentary-accumulation environment, discern the influence of periglacial conditions on the grains, and identify the sediment source(s) for each complex. Based on the results, a conclusion can be reached that the accumulation of Complex I took place as a result of multiple repetitive transportation events recycling the same material and introducing a limited supply of new material into the fluvial environment. Upward in the succession, fluvial-process activities decreased in favour of lake-deposit accumulation. Frozen syngenetic ice-rich silty deposits-yedoma or ice complex-of Complex IV are composed of grains with a precipitated surface, but differ from the underlying deposits in the degree of crusting and mineralogy. Most probably aeolian processes are responsible for their transport. They include a variety of sediments, including older-sourced sediments such as retransported loess and the detritus from mechanical weathering coeval with sediment accumulation. Traces of frost and chemical weathering have been identified on the grain surfaces, the former visible in the form of breakage blocks and conchoidal fracture microtextures and the latter - as surface crusting. However, the frequencies of these microtextures are low, which suggests a relatively high rate of sediment accumulation.
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Affiliation(s)
- A A Kut
- Melnikov Permafrost Institute SB RAS, Yakutsk, Russia.
| | - B Woronko
- University of Warsaw, Faculty of Geology, Warsaw, Poland.
| | - V V Spektor
- Melnikov Permafrost Institute SB RAS, Yakutsk, Russia.
| | - I V Klimova
- Melnikov Permafrost Institute SB RAS, Yakutsk, Russia.
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Yokohata T, Saito K, Ito A, Ohno H, Tanaka K, Hajima T, Iwahana G. Future projection of greenhouse gas emissions due to permafrost degradation using a simple numerical scheme with a global land surface model. PROGRESS IN EARTH AND PLANETARY SCIENCE 2020; 7:56. [PMID: 33088673 PMCID: PMC7532133 DOI: 10.1186/s40645-020-00366-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
The Yedoma layer, a permafrost layer containing a massive amount of underground ice in the Arctic regions, is reported to be rapidly thawing. In this study, we develop the Permafrost Degradation and Greenhouse gasses Emission Model (PDGEM), which describes the thawing of the Arctic permafrost including the Yedoma layer due to climate change and the greenhouse gas (GHG) emissions. The PDGEM includes the processes by which high-concentration GHGs (CO2 and CH4) contained in the pores of the Yedoma layer are released directly by dynamic degradation, as well as the processes by which GHGs are released by the decomposition of organic matter in the Yedoma layer and other permafrost. Our model simulations show that the total GHG emissions from permafrost degradation in the RCP8.5 scenario was estimated to be 31-63 PgC for CO2 and 1261-2821 TgCH4 for CH4 (68th percentile of the perturbed model simulations, corresponding to a global average surface air temperature change of 0.05-0.11 °C), and 14-28 PgC for CO2 and 618-1341 TgCH4 for CH4 (0.03-0.07 °C) in the RCP2.6 scenario. GHG emissions resulting from the dynamic degradation of the Yedoma layer were estimated to be less than 1% of the total emissions from the permafrost in both scenarios, possibly because of the small area ratio of the Yedoma layer. An advantage of PDGEM is that geographical distributions of GHG emissions can be estimated by combining a state-of-the-art land surface model featuring detailed physical processes with a GHG release model using a simple scheme, enabling us to consider a broad range of uncertainty regarding model parameters. In regions with large GHG emissions due to permafrost thawing, it may be possible to help reduce GHG emissions by taking measures such as restraining land development.
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Affiliation(s)
- Tokuta Yokohata
- Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
| | - Kazuyuki Saito
- Research Center for Environmental Modeling and Application, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showamachi, Kanazawaku, Yokohama, 236-0001 Japan
| | - Akihiko Ito
- Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
| | - Hiroshi Ohno
- School of Earth, Energy and Environmental Engineering, Kitami Institute of Technology, 165 Koen-cho, Kitami, 090-8507 Japan
| | - Katsumasa Tanaka
- Center for Global Environmental Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
- Laboratoire des Sciences du Climat et de l’Environnement (LSCE), Commissariat à l’énergie atomique et aux énergies alternatives (CEA), Gif-sur-Yvette, France
| | - Tomohiro Hajima
- Research Center for Environmental Modeling and Application, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showamachi, Kanazawaku, Yokohama, 236-0001 Japan
| | - Go Iwahana
- International Arctic Research Center, 739, The University of Alaska Fairbanks, 2160 Koyukuk Dr, Fairbanks, AK 740 99775-7340 USA
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9
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Lashchinskiy NN, Kartoziia AA, Faguet AN. Permafrost Degradation as a Supporting Factor for the Biodiversity of Tundra Ecosystems. CONTEMP PROBL ECOL+ 2020. [DOI: 10.1134/s1995425520040071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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10
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Dyonisius MN, Petrenko VV, Smith AM, Hua Q, Yang B, Schmitt J, Beck J, Seth B, Bock M, Hmiel B, Vimont I, Menking JA, Shackleton SA, Baggenstos D, Bauska TK, Rhodes RH, Sperlich P, Beaudette R, Harth C, Kalk M, Brook EJ, Fischer H, Severinghaus JP, Weiss RF. Old carbon reservoirs were not important in the deglacial methane budget. Science 2020; 367:907-910. [PMID: 32079770 DOI: 10.1126/science.aax0504] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 01/06/2020] [Indexed: 11/02/2022]
Abstract
Permafrost and methane hydrates are large, climate-sensitive old carbon reservoirs that have the potential to emit large quantities of methane, a potent greenhouse gas, as the Earth continues to warm. We present ice core isotopic measurements of methane (Δ14C, δ13C, and δD) from the last deglaciation, which is a partial analog for modern warming. Our results show that methane emissions from old carbon reservoirs in response to deglacial warming were small (<19 teragrams of methane per year, 95% confidence interval) and argue against similar methane emissions in response to future warming. Our results also indicate that methane emissions from biomass burning in the pre-Industrial Holocene were 22 to 56 teragrams of methane per year (95% confidence interval), which is comparable to today.
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Affiliation(s)
- M N Dyonisius
- Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, USA.
| | - V V Petrenko
- Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, USA
| | - A M Smith
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - Q Hua
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - B Yang
- Australian Nuclear Science and Technology Organisation (ANSTO), Lucas Heights, NSW 2234, Australia
| | - J Schmitt
- Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland
| | - J Beck
- Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland
| | - B Seth
- Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland
| | - M Bock
- Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland
| | - B Hmiel
- Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, USA
| | - I Vimont
- Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO 80303, USA
| | - J A Menking
- College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - S A Shackleton
- Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92037, USA
| | - D Baggenstos
- Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland.,Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92037, USA
| | - T K Bauska
- College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.,British Antarctic Survey High Cross, Cambridge CB3 0ET, UK
| | - R H Rhodes
- College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA.,Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ, UK
| | - P Sperlich
- National Institute of Water and Atmospheric Research (NIWA), 6021 Wellington, New Zealand
| | - R Beaudette
- Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92037, USA
| | - C Harth
- Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92037, USA
| | - M Kalk
- College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - E J Brook
- College of Earth, Ocean and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA
| | - H Fischer
- Climate and Environmental Physics, Physics Institute and Oeschger Centre for Climate Change Research, University of Bern, CH-3012 Bern, Switzerland
| | - J P Severinghaus
- Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92037, USA
| | - R F Weiss
- Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, CA 92037, USA
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Fuchs M, Lenz J, Jock S, Nitze I, Jones BM, Strauss J, Günther F, Grosse G. Organic Carbon and Nitrogen Stocks Along a Thermokarst Lake Sequence in Arctic Alaska. JOURNAL OF GEOPHYSICAL RESEARCH. BIOGEOSCIENCES 2019; 124:1230-1247. [PMID: 31341754 PMCID: PMC6618060 DOI: 10.1029/2018jg004591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 02/13/2019] [Accepted: 02/24/2019] [Indexed: 05/20/2023]
Abstract
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 7,000 years 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.
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Affiliation(s)
- Matthias Fuchs
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute of GeosciencesUniversity of PotsdamPotsdamGermany
| | - Josefine Lenz
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute of Northern Engineering, Water and Environmental Research CenterUniversity of Alaska FairbanksFairbanksAKUSA
| | - Suzanne Jock
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | - Ingmar Nitze
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | - Benjamin M. Jones
- Institute of Northern Engineering, Water and Environmental Research CenterUniversity of Alaska FairbanksFairbanksAKUSA
| | - Jens Strauss
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | - Frank Günther
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute of GeosciencesUniversity of PotsdamPotsdamGermany
- Laboratory Geoecology of the North, Faculty of GeographyLomonosov Moscow State UniversityMoscowRussia
| | - Guido Grosse
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute of GeosciencesUniversity of PotsdamPotsdamGermany
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12
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Quantifying Impacts of Mean Annual Lake Bottom
Temperature on Talik Development and Permafrost
Degradation below Expanding Thermokarst Lakes on
the Qinghai–Tibet Plateau. WATER 2019. [DOI: 10.3390/w11040706] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Variations in thermokarst lake area, lake water depth, lake age, air temperature,permafrost condition, and other environmental variables could have important influences on themean annual lake bottom temperature (MALBT) and thus affect the ground thermal regime andtalik development beneath the lakes through their direct impacts on the MALBT. A lake expandingmodel was employed for examining the impacts of variations in the MALBT on talik developmentand permafrost degradation beneath expanding thermokarst lakes in the Beiluhe Basin on theQinghai–Tibetan Plateau (QTP). All required boundary and initial conditions and model parameterswere determined based on field measurements. Four simulation cases were conducted withdifferent respective fitting sinusoidal functions of the MALBTs at 3.75 °C, 4.5 °C, 5.25 °C, and 6.0 °C.The simulated results show that for lakes with MALBTs of 3.75 °C, 4.5 °C, 5.25 °C, and 6.0 °C, themaximum thicknesses of bowl-shaped talik below the lakes at year 300 were 27.2 m, 29.6 m, 32.0 m,and 34.4 m; funnel-shaped open taliks formed beneath the lakes at years 451, 411, 382, and 356 afterthe formation of thermokarst lakes, with mean downward thaw rates of 9.1 m/year, 10.2 m/year,11.2 m/year, and 12.0 m/year, respectively. Increases in the MALBT from 3.75 °C to 4.52 °C, 4.25 °Cto 5.25 °C, and 5.25 °C to 6.0 °C respectively resulted in the permafrost with a horizontal distance tolake centerline less than or equal to 45 m thawing completely 36 years, 32 years, and 24 years inadvance, and the maximum ground temperature increases at a depth of 40 m below the lakes at year600 ranged from 2.16 °C to 2.80 °C, 3.57 °C, and 4.09 °C, depending on the MALBT. The groundtemperature increases of more than 0.5 °C at a depth of 40 m in year 600 occurred as far as 74.9 m,87.2 m, 97.8 m, and 106.6 m from the lake centerlines. The simulation results also show that changesin the MALBT almost have no impact on the open talik lateral progress rate, although the minimumdistances from the open talik profile to lake centerlines below the lakes with different MALBTsexhibited substantial differences.
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13
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Schuur EA, Mack MC. Ecological Response to Permafrost Thaw and Consequences for Local and Global Ecosystem Services. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2018. [DOI: 10.1146/annurev-ecolsys-121415-032349] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Arctic may seem remote, but the unprecedented environmental changes occurring there have important consequences for global society. Of all Arctic system components, changes in permafrost (perennially frozen ground) are one of the least documented. Permafrost is degrading as a result of climate warming, and evidence is mounting that changing permafrost will have significant impacts within and outside the region. This review asks: What are key structural and functional properties of ecosystems that interact with changing permafrost, and how do these ecosystem changes affect local and global society? Here, we look beyond the classic definition of permafrost to include a broadened focus on the composition of frozen ground, including the ice and the soil organic carbon content, and how it is changing. This ecological perspective of permafrost serves to identify areas of both vulnerability and resilience as climate, ecological disturbance regimes, and the human footprint all continue to change in this sensitive and critical region of Earth.
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Affiliation(s)
| | - Michelle C. Mack
- Center for Ecosystem Science and Society, and Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona 86011, USA
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14
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Portnov A, Mienert J, Winsborrow M, Andreassen K, Vadakkepuliyambatta S, Semenov P, Gataullin V. Shallow carbon storage in ancient buried thermokarst in the South Kara Sea. Sci Rep 2018; 8:14342. [PMID: 30254290 PMCID: PMC6156565 DOI: 10.1038/s41598-018-32826-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 09/14/2018] [Indexed: 11/09/2022] Open
Abstract
Geophysical data from the South Kara Sea reveal U-shaped erosional structures buried beneath the 50–250 m deep seafloor of the continental shelf across an area of ~32 000 km2. These structures are interpreted as thermokarst, formed in ancient yedoma terrains during Quaternary interglacial periods. Based on comparison to modern yedoma terrains, we suggest that these thermokarst features could have stored approximately 0.5 to 8 Gt carbon during past climate warmings. In the deeper parts of the South Kara Sea (>220 m water depth) the paleo thermokarst structures lie within the present day gas hydrate stability zone, with low bottom water temperatures −1.8 oC) keeping the gas hydrate system in equilibrium. These thermokarst structures and their carbon reservoirs remain stable beneath a Quaternary sediment blanket, yet are potentially sensitive to future Arctic climate changes.
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Affiliation(s)
- Alexey Portnov
- School of Earth Sciences, The Ohio State University, Columbus, Ohio, USA. .,CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway.
| | - Jürgen Mienert
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Monica Winsborrow
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Karin Andreassen
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
| | - Sunil Vadakkepuliyambatta
- CAGE - Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, 9037, Tromsø, Norway
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15
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Gao Z, Niu F, Lin Z, Luo J, Yin G, Wang Y. Evaluation of thermokarst lake water balance in the Qinghai-Tibet Plateau via isotope tracers. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 636:1-11. [PMID: 29702397 DOI: 10.1016/j.scitotenv.2018.04.103] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/19/2018] [Accepted: 04/06/2018] [Indexed: 06/08/2023]
Abstract
Thermokarst lakes are a ubiquitous landscape feature, which widely distributed in the pan-arctic and some low latitude regions, and are associated with regional hydrological processes. The studies were taken to obtain a better understanding of the water balance of thermokarst lakes in the Qinghai-Tibet Plateau (QTP) in order to gain insight of the regional hydrological cycle. The characteristics of the stable isotopes δ 18O and δ D were investigated in precipitation, permafrost meltwater, and thermokarst lake water in the continuous permafrost region of the QTP and analyzed the lake water balance using the isotope mass model. The results showed that the δ D-δ 18O relationship in the thermokarst lakes (δ D = 5.45 δ 18O - 18.95) differed from that of the local precipitation (δ D = 8.30 δ 18O + 18.49) and permafrost meltwater (δ D = 5.78 δ 18O - 23.41), and the mean isotope compositions in the thermokarst lakes were -7.2‰ in δ 18O and -58.0‰ in δ D. The more positive isotope signals in thermokarst lakes than in the precipitation and permafrost meltwater revealed that the lakes had experienced stronger isotope enrichment. Additionally, the evaporation-to-inflow ratio (E/I) values were < 1 in most of the thermokarst lakes (84%), which might be explained by the recent expansion of the lake surfaces. However, 16% of the thermokarst lakes had shrunk, owing to thermokarst erosion, lateral expansion as the temperature increases, and lower recharge volume. Moreover, precipitation on the lake surface was only 14-18% of the inflow volume in the thermokarst lakes, and the surface-subsurface inflow and permafrost meltwater are very important for recharging the lakes and maintaining the water balance. The results of this study provide a comprehensive understanding of the influence of climate warming on hydrological processes in the permafrost regions in the QTP.
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Affiliation(s)
- Zeyong Gao
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, 320 Donggang West Road, Lanzhou, Gansu Province 730000, PR China; University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, PR China; College of Earth and Environment Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, Gansu Province 730000, PR China
| | - Fujun Niu
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, 320 Donggang West Road, Lanzhou, Gansu Province 730000, PR China; South China Institute of Geotechnical Engineering, School of Civil Engineering and Transportation, South China University of Technology, Guangzhou 510006, PR China.
| | - Zhanju Lin
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, 320 Donggang West Road, Lanzhou, Gansu Province 730000, PR China
| | - Jing Luo
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, 320 Donggang West Road, Lanzhou, Gansu Province 730000, PR China
| | - Guoan Yin
- State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-Environment and Resources, CAS, 320 Donggang West Road, Lanzhou, Gansu Province 730000, PR China
| | - Yibo Wang
- College of Earth and Environment Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, Gansu Province 730000, PR China
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16
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Deglacial mobilization of pre-aged terrestrial carbon from degrading permafrost. Nat Commun 2018; 9:3666. [PMID: 30201999 PMCID: PMC6131488 DOI: 10.1038/s41467-018-06080-w] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 08/13/2018] [Indexed: 11/16/2022] Open
Abstract
The mobilization of glacial permafrost carbon during the last glacial–interglacial transition has been suggested by indirect evidence to be an additional and significant source of greenhouse gases to the atmosphere, especially at times of rapid sea-level rise. Here we present the first direct evidence for the release of ancient carbon from degrading permafrost in East Asia during the last 17 kyrs, using biomarkers and radiocarbon dating of terrigenous material found in two sediment cores from the Okhotsk Sea. Upscaling our results to the whole Arctic shelf area, we show by carbon cycle simulations that deglacial permafrost-carbon release through sea-level rise likely contributed significantly to the changes in atmospheric CO2 around 14.6 and 11.5 kyrs BP. Permafrost-derived carbon (C) may have been an additional source of greenhouse gases during the last glacial-interglacial transition. Here the authors show that ancient C from degrading permafrost was mobilised during phases of rapid sea-level rise, partially explaining changes in atmospheric CO2 and ∆14C.
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17
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21st-century modeled permafrost carbon emissions accelerated by abrupt thaw beneath lakes. Nat Commun 2018; 9:3262. [PMID: 30111815 PMCID: PMC6093858 DOI: 10.1038/s41467-018-05738-9] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 07/17/2018] [Indexed: 12/01/2022] Open
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. Permafrost carbon feedback modeling has focused on gradual thaw of near-surface permafrost leading to greenhouse gas emissions that accelerate climate change. Here the authors show that deeper, abrupt thaw beneath lakes will more than double radiative forcing from permafrost-soil carbon fluxes this century.
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18
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Extensive loss of past permafrost carbon but a net accumulation into present-day soils. Nature 2018; 560:219-222. [PMID: 30069043 DOI: 10.1038/s41586-018-0371-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 05/14/2018] [Indexed: 11/09/2022]
Abstract
Atmospheric concentrations of carbon dioxide increased between the Last Glacial Maximum (LGM, around 21,000 years ago) and the preindustrial era1. It is thought that the evolution of this atmospheric carbon dioxide (and that of atmospheric methane) during the glacial-to-interglacial transition was influenced by organic carbon that was stored in permafrost during the LGM and then underwent decomposition and release following thaw2,3. It has also been suggested that the rather erratic atmospheric δ13C and ∆14C signals seen during deglaciation1,4 could partly be explained by the presence of a large terrestrial inert LGM carbon stock, despite the biosphere being less productive (and therefore storing less carbon)5,6. Here we present an empirically derived estimate of the carbon stored in permafrost during the LGM by reconstructing the extent and carbon content of LGM biomes, peatland regions and deep sedimentary deposits. We find that the total estimated soil carbon stock for the LGM northern permafrost region is smaller than the estimated present-day storage (in both permafrost and non-permafrost soils) for the same region. A substantial decrease in the permafrost area from the LGM to the present day has been accompanied by a roughly 400-petagram increase in the total soil carbon stock. This increase in soil carbon suggests that permafrost carbon has made no net contribution to the atmospheric carbon pool since the LGM. However, our results also indicate potential postglacial reductions in the portion of the carbon stock that is trapped in permafrost, of around 1,000 petagrams, supporting earlier studies7. We further find that carbon has shifted from being primarily stored in permafrost mineral soils and loess deposits during the LGM, to being roughly equally divided between peatlands, mineral soils and permafrost loess deposits today.
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19
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Lifshits SK, Spektor VB, Kershengolts BM, Spektor VV. The Role of Methane and Methane Hydrates in the Evolution of Global Climate. ACTA ACUST UNITED AC 2018. [DOI: 10.4236/ajcc.2018.72016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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20
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Minimal geological methane emissions during the Younger Dryas–Preboreal abrupt warming event. Nature 2017; 548:443-446. [DOI: 10.1038/nature23316] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 06/21/2017] [Indexed: 11/08/2022]
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21
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Bock M, Schmitt J, Beck J, Seth B, Chappellaz J, Fischer H. Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH 4 ice core records. Proc Natl Acad Sci U S A 2017; 114:E5778-E5786. [PMID: 28673973 PMCID: PMC5530640 DOI: 10.1073/pnas.1613883114] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Atmospheric methane (CH4) records reconstructed from polar ice cores represent an integrated view on processes predominantly taking place in the terrestrial biogeosphere. Here, we present dual stable isotopic methane records [δ13CH4 and δD(CH4)] from four Antarctic ice cores, which provide improved constraints on past changes in natural methane sources. Our isotope data show that tropical wetlands and seasonally inundated floodplains are most likely the controlling sources of atmospheric methane variations for the current and two older interglacials and their preceding glacial maxima. The changes in these sources are steered by variations in temperature, precipitation, and the water table as modulated by insolation, (local) sea level, and monsoon intensity. Based on our δD(CH4) constraint, it seems that geologic emissions of methane may play a steady but only minor role in atmospheric CH4 changes and that the glacial budget is not dominated by these sources. Superimposed on the glacial/interglacial variations is a marked difference in both isotope records, with systematically higher values during the last 25,000 y compared with older time periods. This shift cannot be explained by climatic changes. Rather, our isotopic methane budget points to a marked increase in fire activity, possibly caused by biome changes and accumulation of fuel related to the late Pleistocene megafauna extinction, which took place in the course of the last glacial.
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Affiliation(s)
- Michael Bock
- Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland;
- Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Jochen Schmitt
- Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Jonas Beck
- Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Barbara Seth
- Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland
- Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
| | - Jérôme Chappellaz
- CNRS, IGE (Institut des Géosciences de l'Environnement), F-38000 Grenoble, France
- University of Grenoble Alpes, IGE, F-38000 Grenoble, France
- IRD (Institut de Recherche pour le Développement), IGE, F-38000 Grenoble, France
- Grenoble INP (Institut National Polytechnique), IGE, F-38000 Grenoble, France
| | - Hubertus Fischer
- Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland;
- Oeschger Centre for Climate Change Research, University of Bern, 3012 Bern, Switzerland
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22
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Cryogenic Displacement and Accumulation of Biogenic Methane in Frozen Soils. ATMOSPHERE 2017. [DOI: 10.3390/atmos8060105] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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23
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Jones MC, Harden J, O'Donnell J, Manies K, Jorgenson T, Treat C, Ewing S. Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands. GLOBAL CHANGE BIOLOGY 2017; 23:1109-1127. [PMID: 27362936 DOI: 10.1111/gcb.13403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/24/2016] [Indexed: 06/06/2023]
Abstract
Permafrost peatlands store one-third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high-latitude temperatures warm. Large uncertainties remain about C dynamics following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age from young (<10 years) to old (>100 years) from two interior Alaska chronosequences. Permafrost originally aggraded simultaneously with peat accumulation (syngenetic permafrost) at both sites. We found that upon thaw, C loss of the forest peat C is equivalent to ~30% of the initial forest C stock and is directly proportional to the prethaw C stocks. Our model results indicate that permafrost thaw turned these peatlands into net C sources to the atmosphere for a decade following thaw, after which post-thaw bog peat accumulation returned sites to net C sinks. It can take multiple centuries to millennia for a site to recover its prethaw C stocks; the amount of time needed for them to regain their prethaw C stocks is governed by the amount of C that accumulated prior to thaw. Consequently, these findings show that older peatlands will take longer to recover prethaw C stocks, whereas younger peatlands will exceed prethaw stocks in a matter of centuries. We conclude that the loss of sporadic and discontinuous permafrost by 2100 could result in a loss of up to 24 Pg of deep C from permafrost peatlands.
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Affiliation(s)
| | | | | | | | | | - Claire Treat
- U.S. Geological Survey, Menlo Park, CA, USA
- University of Alaska Fairbanks, Fairbanks, AK, USA
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24
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Tanski G, Lantuit H, Ruttor S, Knoblauch C, Radosavljevic B, Strauss J, Wolter J, Irrgang AM, Ramage J, Fritz M. Transformation of terrestrial organic matter along thermokarst-affected permafrost coasts in the Arctic. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 581-582:434-447. [PMID: 28088543 DOI: 10.1016/j.scitotenv.2016.12.152] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 12/22/2016] [Accepted: 12/22/2016] [Indexed: 05/21/2023]
Abstract
The changing climate in the Arctic has a profound impact on permafrost coasts, which are subject to intensified thermokarst formation and erosion. Consequently, terrestrial organic matter (OM) is mobilized and transported into the nearshore zone. Yet, little is known about the fate of mobilized OM before and after entering the ocean. In this study we investigated a retrogressive thaw slump (RTS) on Qikiqtaruk - Herschel Island (Yukon coast, Canada). The RTS was classified into an undisturbed, a disturbed (thermokarst-affected) and a nearshore zone and sampled systematically along transects. Samples were analyzed for total and dissolved organic carbon and nitrogen (TOC, DOC, TN, DN), stable carbon isotopes (δ13C-TOC, δ13C-DOC), and dissolved inorganic nitrogen (DIN), which were compared between the zones. C/N-ratios, δ13C signatures, and ammonium (NH4-N) concentrations were used as indicators for OM degradation along with biomarkers (n-alkanes, n-fatty acids, n-alcohols). Our results show that OM significantly decreases after disturbance with a TOC and DOC loss of 77 and 55% and a TN and DN loss of 53 and 48%, respectively. C/N-ratios decrease significantly, whereas NH4-N concentrations slightly increase in freshly thawed material. In the nearshore zone, OM contents are comparable to the disturbed zone. We suggest that the strong decrease in OM is caused by initial dilution with melted massive ice and immediate offshore transport via the thaw stream. In the mudpool and thaw stream, OM is subject to degradation, whereas in the slump floor the nitrogen decrease is caused by recolonizing vegetation. Within the nearshore zone of the ocean, heavier portions of OM are directly buried in marine sediments close to shore. We conclude that RTS have profound impacts on coastal environments in the Arctic. They mobilize nutrients from permafrost, substantially decrease OM contents and provide fresh water and nutrients at a point source.
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Affiliation(s)
- George Tanski
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Hugues Lantuit
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Saskia Ruttor
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | | | - Boris Radosavljevic
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Jens Strauss
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany.
| | - Juliane Wolter
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Anna M Irrgang
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Justine Ramage
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany; Potsdam University, Institute of Earth and Environmental Sciences, Potsdam, Germany.
| | - Michael Fritz
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Periglacial Research Unit, Potsdam, Germany.
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Gao Z, Niu F, Wang Y, Luo J, Lin Z. Impact of a thermokarst lake on the soil hydrological properties in permafrost regions of the Qinghai-Tibet Plateau, China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 574:751-759. [PMID: 27664762 DOI: 10.1016/j.scitotenv.2016.09.108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/13/2016] [Accepted: 09/13/2016] [Indexed: 06/06/2023]
Abstract
The formation of thermokarst lakes can degrade alpine meadow ecosystems through changes in soil water and heat properties, which might have an effect on the regional surface water and groundwater processes. In this study, a typical thermokarst lake was selected in the Qinghai-Tibet Plateau (QTP), and the ecological index (SL) was used to divide the affected areas into extremely affected, severely affected, medium-affected, lightly affected, and non-affected areas, and soil hydrological properties, including saturated hydraulic conductivity and soil water-holding capacity, were investigated. The results showed that the formation of a thermokarst lake can lead to the degradation of alpine meadows, accompanied by a change in the soil physiochemical and hydrological properties. Specifically, the soil structure turned towards loose soil and the soil nutrients decreased from non-affected areas to severely affected areas, but the soil organic matter and available potassium increased slightly in the extremely affected areas. Soil saturated hydraulic conductivity showed a 1.7- to 4.1-fold increase in the lake-surrounding areas, and the highest value (401.9cmd-1) was detected in the severely affected area. Soil water-holding capacity decreased gradually during the transition from the non-affected areas to the severely affected areas, but it increased slightly in the extremely affected areas. The principal component analysis showed that the plant biomass was vital to the changes in soil hydrological properties. Thus, the vegetation might serve as a link between the thermokarst lake and soil hydrological properties. In this particular case, it was concluded that the thermokarst lake adversely affected the regional hydrological services in the alpine ecosystem. These results would be useful for describing appropriate hydraulic parameters with the purpose of modeling soil water transportation more accurately in the Qinghai-Tibet Plateau.
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Affiliation(s)
- Zeyong Gao
- State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China; University of Chinese Academy of Sciences, Beijing 100049, China; College of Earth and Environment Sciences, Lanzhou University, Lanzhou 730000, China
| | - Fujun Niu
- State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Yibo Wang
- College of Earth and Environment Sciences, Lanzhou University, Lanzhou 730000, China
| | - Jing Luo
- State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
| | - Zhanju Lin
- State Key Laboratory of Frozen Soil Engineering, Cold and Arid Regions Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou 730000, China
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Massive remobilization of permafrost carbon during post-glacial warming. Nat Commun 2016; 7:13653. [PMID: 27897191 PMCID: PMC5141343 DOI: 10.1038/ncomms13653] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Accepted: 10/19/2016] [Indexed: 11/25/2022] Open
Abstract
Recent hypotheses, based on atmospheric records and models, suggest that permafrost carbon (PF-C) accumulated during the last glaciation may have been an important source for the atmospheric CO2 rise during post-glacial warming. However, direct physical indications for such PF-C release have so far been absent. Here we use the Laptev Sea (Arctic Ocean) as an archive to investigate PF-C destabilization during the last glacial–interglacial period. Our results show evidence for massive supply of PF-C from Siberian soils as a result of severe active layer deepening in response to the warming. Thawing of PF-C must also have brought about an enhanced organic matter respiration and, thus, these findings suggest that PF-C may indeed have been an important source of CO2 across the extensive permafrost domain. The results challenge current paradigms on the post-glacial CO2 rise and, at the same time, serve as a harbinger for possible consequences of the present-day warming of PF-C soils. Atmospheric CO2 increases during the last deglaciation have been linked to the destabilisation of permafrost carbon reservoirs. Here, using a sediment core from the Laptev Sea, Tesi et al. indicate a massive supply of permafrost carbon was released from Siberia following active layer deepening.
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Vaughn LJS, Conrad ME, Bill M, Torn MS. Isotopic insights into methane production, oxidation, and emissions in Arctic polygon tundra. GLOBAL CHANGE BIOLOGY 2016; 22:3487-3502. [PMID: 26990225 DOI: 10.1111/gcb.13281] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 02/21/2016] [Accepted: 02/24/2016] [Indexed: 06/05/2023]
Abstract
Arctic wetlands are currently net sources of atmospheric CH4 . Due to their complex biogeochemical controls and high spatial and temporal variability, current net CH4 emissions and gross CH4 processes have been difficult to quantify, and their predicted responses to climate change remain uncertain. We investigated CH4 production, oxidation, and surface emissions in Arctic polygon tundra, across a wet-to-dry permafrost degradation gradient from low-centered (intact) to flat- and high-centered (degraded) polygons. From 3 microtopographic positions (polygon centers, rims, and troughs) along the permafrost degradation gradient, we measured surface CH4 and CO2 fluxes, concentrations and stable isotope compositions of CH4 and DIC at three depths in the soil, and soil moisture and temperature. More degraded sites had lower CH4 emissions, a different primary methanogenic pathway, and greater CH4 oxidation than did intact permafrost sites, to a greater degree than soil moisture or temperature could explain. Surface CH4 flux decreased from 64 nmol m(-2) s(-1) in intact polygons to 7 nmol m(-2) s(-1) in degraded polygons, and stable isotope signatures of CH4 and DIC showed that acetate cleavage dominated CH4 production in low-centered polygons, while CO2 reduction was the primary pathway in degraded polygons. We see evidence that differences in water flow and vegetation between intact and degraded polygons contributed to these observations. In contrast to many previous studies, these findings document a mechanism whereby permafrost degradation can lead to local decreases in tundra CH4 emissions.
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Affiliation(s)
- Lydia J S Vaughn
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Energy and Resources Group, University of California, 310 Barrows Hall, Berkeley, CA, 94720-3050, USA
| | - Mark E Conrad
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Markus Bill
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
| | - Margaret S Torn
- Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA
- Energy and Resources Group, University of California, 310 Barrows Hall, Berkeley, CA, 94720-3050, USA
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Abbott BW, Jones JB. Permafrost collapse alters soil carbon stocks, respiration, CH4 , and N2O in upland tundra. GLOBAL CHANGE BIOLOGY 2015; 21:4570-4587. [PMID: 26301544 DOI: 10.1111/gcb.13069] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Accepted: 08/12/2015] [Indexed: 06/04/2023]
Abstract
Release of greenhouse gases from thawing permafrost is potentially the largest terrestrial feedback to climate change and one of the most likely to occur; however, estimates of its strength vary by a factor of thirty. Some of this uncertainty stems from abrupt thaw processes known as thermokarst (permafrost collapse due to ground ice melt), which alter controls on carbon and nitrogen cycling and expose organic matter from meters below the surface. Thermokarst may affect 20-50% of tundra uplands by the end of the century; however, little is known about the effect of different thermokarst morphologies on carbon and nitrogen release. We measured soil organic matter displacement, ecosystem respiration, and soil gas concentrations at 26 upland thermokarst features on the North Slope of Alaska. Features included the three most common upland thermokarst morphologies: active-layer detachment slides, thermo-erosion gullies, and retrogressive thaw slumps. We found that thermokarst morphology interacted with landscape parameters to determine both the initial displacement of organic matter and subsequent carbon and nitrogen cycling. The large proportion of ecosystem carbon exported off-site by slumps and slides resulted in decreased ecosystem respiration postfailure, while gullies removed a smaller portion of ecosystem carbon but strongly increased respiration and N2 O concentration. Elevated N2 O in gully soils persisted through most of the growing season, indicating sustained nitrification and denitrification in disturbed soils, representing a potential noncarbon permafrost climate feedback. While upland thermokarst formation did not substantially alter redox conditions within features, it redistributed organic matter into both oxic and anoxic environments. Across morphologies, residual organic matter cover, and predisturbance respiration explained 83% of the variation in respiration response. Consistent differences between upland thermokarst types may contribute to the incorporation of this nonlinear process into projections of carbon and nitrogen release from degrading permafrost.
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Affiliation(s)
- Benjamin W Abbott
- OSUR, CNRS, UMR 6553 ECOBIO, Université de Rennes 1, Rennes, France
- Department of Biology and Wildlife and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Jeremy B Jones
- Department of Biology and Wildlife and Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, USA
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29
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Climate change and the permafrost carbon feedback. Nature 2015; 520:171-9. [DOI: 10.1038/nature14338] [Citation(s) in RCA: 1830] [Impact Index Per Article: 203.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 02/12/2015] [Indexed: 11/08/2022]
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Two metagenomes from late pleistocene northeast siberian permafrost. GENOME ANNOUNCEMENTS 2015; 3:3/1/e01380-14. [PMID: 25555741 PMCID: PMC4293628 DOI: 10.1128/genomea.01380-14] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study reports metagenomic shotgun sequencing of microbial communities of two ancient permafrost horizons of the Russian Arctic. Results demonstrate a significant difference in microbial community structure of the analyzed samples in general and microorganisms of the methane cycle in particular.
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Spatio-Temporal Analysis of Gyres in Oriented Lakes on the Arctic Coastal Plain of Northern Alaska Based on Remotely Sensed Images. REMOTE SENSING 2014. [DOI: 10.3390/rs6109170] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Anthony KMW, Zimov SA, Grosse G, Jones MC, Anthony PM, Chapin FS, Finlay JC, Mack MC, Davydov S, Frenzel P, Frolking S. A shift of thermokarst lakes from carbon sources to sinks during the Holocene epoch. Nature 2014; 511:452-6. [PMID: 25043014 DOI: 10.1038/nature13560] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 06/02/2014] [Indexed: 11/09/2022]
Abstract
Thermokarst lakes formed across vast regions of Siberia and Alaska during the last deglaciation and are thought to be a net source of atmospheric methane and carbon dioxide during the Holocene epoch. However, the same thermokarst lakes can also sequester carbon, and it remains uncertain whether carbon uptake by thermokarst lakes can offset their greenhouse gas emissions. Here we use field observations of Siberian permafrost exposures, radiocarbon dating and spatial analyses to quantify Holocene carbon stocks and fluxes in lake sediments overlying thawed Pleistocene-aged permafrost. We find that carbon accumulation in deep thermokarst-lake sediments since the last deglaciation is about 1.6 times larger than the mass of Pleistocene-aged permafrost carbon released as greenhouse gases when the lakes first formed. Although methane and carbon dioxide emissions following thaw lead to immediate radiative warming, carbon uptake in peat-rich sediments occurs over millennial timescales. We assess thermokarst-lake carbon feedbacks to climate with an atmospheric perturbation model and find that thermokarst basins switched from a net radiative warming to a net cooling climate effect about 5,000 years ago. High rates of Holocene carbon accumulation in 20 lake sediments (47 ± 10 grams of carbon per square metre per year; mean ± standard error) were driven by thermokarst erosion and deposition of terrestrial organic matter, by nutrient release from thawing permafrost that stimulated lake productivity and by slow decomposition in cold, anoxic lake bottoms. When lakes eventually drained, permafrost formation rapidly sequestered sediment carbon. Our estimate of about 160 petagrams of Holocene organic carbon in deep lake basins of Siberia and Alaska increases the circumpolar peat carbon pool estimate for permafrost regions by over 50 per cent (ref. 6). The carbon in perennially frozen drained lake sediments may become vulnerable to mineralization as permafrost disappears, potentially negating the climate stabilization provided by thermokarst lakes during the late Holocene.
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Affiliation(s)
- K M Walter Anthony
- Water and Environmental Research Center, University of Alaska, Fairbanks, Alaska 99775-5860, USA
| | - S A Zimov
- Northeast Scientific Station, Pacific Institute for Geography, Far-East Branch, Russian Academy of Sciences, Cherskii 678830, Russia
| | - G Grosse
- 1] Geophysical Institute, University of Alaska, Fairbanks, Alaska 99775-7320, USA [2] Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam 14473, Germany
| | - M C Jones
- 1] Water and Environmental Research Center, University of Alaska, Fairbanks, Alaska 99775-5860, USA [2] US Geological Survey, Reston, Virginia 20192, USA
| | - P M Anthony
- Water and Environmental Research Center, University of Alaska, Fairbanks, Alaska 99775-5860, USA
| | - F S Chapin
- Institute of Arctic Biology, University of Alaska, Fairbanks, Alaska 99775-7000, USA
| | - J C Finlay
- Department of Ecology, Evolution and Behavior, University of Minnesota, Saint Paul, Minnesota 55108, USA
| | - M C Mack
- Department of Biology, University of Florida, Gainesville, Florida 32611, USA
| | - S Davydov
- Northeast Scientific Station, Pacific Institute for Geography, Far-East Branch, Russian Academy of Sciences, Cherskii 678830, Russia
| | - P Frenzel
- Max Planck Institute for Terrestrial Microbiology, Marburg 35043, Germany
| | - S Frolking
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, New Hampshire 03824-3525, USA
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Zimov S, Zimov N. Role of megafauna and frozen soil in the atmospheric CH4 dynamics. PLoS One 2014; 9:e93331. [PMID: 24695117 PMCID: PMC3973675 DOI: 10.1371/journal.pone.0093331] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 03/05/2014] [Indexed: 11/19/2022] Open
Abstract
Modern wetlands are the world’s strongest methane source. But what was the role of this source in the past? An analysis of global 14C data for basal peat combined with modelling of wetland succession allowed us to reconstruct the dynamics of global wetland methane emission through time. These data show that the rise of atmospheric methane concentrations during the Pleistocene-Holocene transition was not connected with wetland expansion, but rather started substantially later, only 9 thousand years ago. Additionally, wetland expansion took place against the background of a decline in atmospheric methane concentration. The isotopic composition of methane varies according to source. Owing to ice sheet drilling programs past dynamics of atmospheric methane isotopic composition is now known. For example over the course of Pleistocene-Holocene transition atmospheric methane became depleted in the deuterium isotope, which indicated that the rise in methane concentrations was not connected with activation of the deuterium-rich gas clathrates. Modelling of the budget of the atmospheric methane and its isotopic composition allowed us to reconstruct the dynamics of all main methane sources. For the late Pleistocene, the largest methane source was megaherbivores, whose total biomass is estimated to have exceeded that of present-day humans and domestic animals. This corresponds with our independent estimates of herbivore density on the pastures of the late Pleistocene based on herbivore skeleton density in the permafrost. During deglaciation, the largest methane emissions originated from degrading frozen soils of the mammoth steppe biome. Methane from this source is unique, as it is depleted of all isotopes. We estimated that over the entire course of deglaciation (15,000 to 6,000 year before present), soils of the mammoth steppe released 300–550 Pg (1015 g) of methane. From current study we conclude that the Late Quaternary Extinction significantly affected the global methane cycle.
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Affiliation(s)
- Sergey Zimov
- Northeast Science Station, Pacific Institute for Geography, Russian Academy of Sciences, Cherskii, Russia
- * E-mail:
| | - Nikita Zimov
- Northeast Science Station, Pacific Institute for Geography, Russian Academy of Sciences, Cherskii, Russia
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Chen H, Zhu Q, Peng C, Wu N, Wang Y, Fang X, Gao Y, Zhu D, Yang G, Tian J, Kang X, Piao S, Ouyang H, Xiang W, Luo Z, Jiang H, Song X, Zhang Y, Yu G, Zhao X, Gong P, Yao T, Wu J. The impacts of climate change and human activities on biogeochemical cycles on the Qinghai-Tibetan Plateau. GLOBAL CHANGE BIOLOGY 2013; 19:2940-55. [PMID: 23744573 DOI: 10.1111/gcb.12277] [Citation(s) in RCA: 270] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 05/12/2013] [Indexed: 05/13/2023]
Abstract
With a pace of about twice the observed rate of global warming, the temperature on the Qinghai-Tibetan Plateau (Earth's 'third pole') has increased by 0.2 °C per decade over the past 50 years, which results in significant permafrost thawing and glacier retreat. Our review suggested that warming enhanced net primary production and soil respiration, decreased methane (CH(4)) emissions from wetlands and increased CH(4) consumption of meadows, but might increase CH(4) emissions from lakes. Warming-induced permafrost thawing and glaciers melting would also result in substantial emission of old carbon dioxide (CO(2)) and CH(4). Nitrous oxide (N(2)O) emission was not stimulated by warming itself, but might be slightly enhanced by wetting. However, there are many uncertainties in such biogeochemical cycles under climate change. Human activities (e.g. grazing, land cover changes) further modified the biogeochemical cycles and amplified such uncertainties on the plateau. If the projected warming and wetting continues, the future biogeochemical cycles will be more complicated. So facing research in this field is an ongoing challenge of integrating field observations with process-based ecosystem models to predict the impacts of future climate change and human activities at various temporal and spatial scales. To reduce the uncertainties and to improve the precision of the predictions of the impacts of climate change and human activities on biogeochemical cycles, efforts should focus on conducting more field observation studies, integrating data within improved models, and developing new knowledge about coupling among carbon, nitrogen, and phosphorus biogeochemical cycles as well as about the role of microbes in these cycles.
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Affiliation(s)
- Huai Chen
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, 610041, China; Laboratory for Ecological Forecasting and Global Change, College of Forestry, Northwest Agriculture and Forest University, Yangling, 712100, China; Zoige Peatland and Global Change Research Station, Chinese Academy of Sciences, Hongyuan, 624400, China
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Upscaling of Peatland-Atmosphere Fluxes of Methane: Small-Scale Heterogeneity in Process Rates and the Pitfalls of “Bucket-and-Slab” Models. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/2008gm000826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Chen H, Zhu Q, Peng C, Wu N, Wang Y, Fang X, Jiang H, Xiang W, Chang J, Deng X, Yu G. Methane emissions from rice paddies natural wetlands, and lakes in China: synthesis and new estimate. GLOBAL CHANGE BIOLOGY 2013; 19:19-32. [PMID: 23504718 DOI: 10.1111/gcb.12034] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 07/13/2012] [Accepted: 08/11/2012] [Indexed: 06/01/2023]
Abstract
Sources of methane (CH4 ) become highly variable for countries undergoing a heightened period of development due to both human activity and climate change. An urgent need therefore exists to budget key sources of CH4 , such as wetlands (rice paddies and natural wetlands) and lakes (including reservoirs and ponds), which are sensitive to these changes. For this study, references in relation to CH4 emissions from rice paddies, natural wetlands, and lakes in China were first reviewed and then reestimated based on the review itself. Total emissions from the three CH4 sources were 11.25 Tg CH4 yr(-1) (ranging from 7.98 to 15.16 Tg CH4 yr(-1) ). Among the emissions, 8.11 Tg CH4 yr(-1) (ranging from 5.20 to 11.36 Tg CH4 yr(-1) ) derived from rice paddies, 2.69 Tg CH4 yr(-1) (ranging from 2.46 to 3.20 Tg CH4 yr(-1) ) from natural wetlands, and 0.46 Tg CH4 yr(-1) (ranging from 0.33 to 0.59 Tg CH4 yr(-1) ) from lakes (including reservoirs and ponds). Plentiful water and warm conditions, as well as its large rice paddy area make rice paddies in southeastern China the greatest overall source of CH4 , accounting for approximately 55% of total paddy emissions. Natural wetland estimates were slightly higher than the other estimates owing to the higher CH4 emissions recorded within Qinghai-Tibetan Plateau peatlands. Total CH4 emissions from lakes were estimated for the first time by this study, with three quarters from the littoral zone and one quarter from lake surfaces. Rice paddies, natural wetlands, and lakes are not constant sources of CH4 , but decreasing ones influenced by anthropogenic activity and climate change. A new progress-based model used in conjunction with more observations through model-data fusion approach could help obtain better estimates and insights with regard to CH4 emissions deriving from wetlands and lakes in China.
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Affiliation(s)
- Huai Chen
- Laboratory for Ecological Forecasting and Global Change, Northwest A&F University, Yangling, 712100, China.
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Stolaroff JK, Bhattacharyya S, Smith CA, Bourcier WL, Cameron-Smith PJ, Aines RD. Review of methane mitigation technologies with application to rapid release of methane from the Arctic. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:6455-6469. [PMID: 22594483 DOI: 10.1021/es204686w] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Methane is the most important greenhouse gas after carbon dioxide, with particular influence on near-term climate change. It poses increasing risk in the future from both direct anthropogenic sources and potential rapid release from the Arctic. A range of mitigation (emissions control) technologies have been developed for anthropogenic sources that can be developed for further application, including to Arctic sources. Significant gaps in understanding remain of the mechanisms, magnitude, and likelihood of rapid methane release from the Arctic. Methane may be released by several pathways, including lakes, wetlands, and oceans, and may be either uniform over large areas or concentrated in patches. Across Arctic sources, bubbles originating in the sediment are the most important mechanism for methane to reach the atmosphere. Most known technologies operate on confined gas streams of 0.1% methane or more, and may be applicable to limited Arctic sources where methane is concentrated in pockets. However, some mitigation strategies developed for rice paddies and agricultural soils are promising for Arctic wetlands and thawing permafrost. Other mitigation strategies specific to the Arctic have been proposed but have yet to be studied. Overall, we identify four avenues of research and development that can serve the dual purposes of addressing current methane sources and potential Arctic sources: (1) methane release detection and quantification, (2) mitigation units for small and remote methane streams, (3) mitigation methods for dilute (<1000 ppm) methane streams, and (4) understanding methanotroph and methanogen ecology.
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Affiliation(s)
- Joshuah K Stolaroff
- Lawrence Livermore National Laboratory, Livermore, California, United States.
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Kessler MA, Plug LJ, Walter Anthony KM. Simulating the decadal- to millennial-scale dynamics of morphology and sequestered carbon mobilization of two thermokarst lakes in NW Alaska. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jg001796] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Brosius LS, Walter Anthony KM, Grosse G, Chanton JP, Farquharson LM, Overduin PP, Meyer H. Using the deuterium isotope composition of permafrost meltwater to constrain thermokarst lake contributions to atmospheric CH4during the last deglaciation. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011jg001810] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Bouchard F, Francus P, Pienitz R, Laurion I. Sedimentology and geochemistry of thermokarst ponds in discontinuous permafrost, subarctic Quebec, Canada. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jg001675] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jones BM, Grosse G, Arp CD, Jones MC, Walter Anthony KM, Romanovsky VE. Modern thermokarst lake dynamics in the continuous permafrost zone, northern Seward Peninsula, Alaska. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jg001666] [Citation(s) in RCA: 206] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Sannel ABK, Kuhry P. Warming-induced destabilization of peat plateau/thermokarst lake complexes. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jg001635] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Schirrmeister L, Grosse G, Wetterich S, Overduin PP, Strauss J, Schuur EAG, Hubberten HW. Fossil organic matter characteristics in permafrost deposits of the northeast Siberian Arctic. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011jg001647] [Citation(s) in RCA: 124] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Callaghan TV, Tweedie CE, Åkerman J, Andrews C, Bergstedt J, Butler MG, Christensen TR, Cooley D, Dahlberg U, Danby RK, Daniёls FJA, de Molenaar JG, Dick J, Mortensen CE, Ebert-May D, Emanuelsson U, Eriksson H, Hedenås H, Henry GHR, Hik DS, Hobbie JE, Jantze EJ, Jaspers C, Johansson C, Johansson M, Johnson DR, Johnstone JF, Jonasson C, Kennedy C, Kenney AJ, Keuper F, Koh S, Krebs CJ, Lantuit H, Lara MJ, Lin D, Lougheed VL, Madsen J, Matveyeva N, McEwen DC, Myers-Smith IH, Narozhniy YK, Olsson H, Pohjola VA, Price LW, Rigét F, Rundqvist S, Sandström A, Tamstorf M, Van Bogaert R, Villarreal S, Webber PJ, Zemtsov VA. Multi-decadal changes in tundra environments and ecosystems: synthesis of the International Polar Year-Back to the Future project (IPY-BTF). AMBIO 2011; 40:705-16. [PMID: 21954732 PMCID: PMC3357861 DOI: 10.1007/s13280-011-0179-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Understanding the responses of tundra systems to global change has global implications. Most tundra regions lack sustained environmental monitoring and one of the only ways to document multi-decadal change is to resample historic research sites. The International Polar Year (IPY) provided a unique opportunity for such research through the Back to the Future (BTF) project (IPY project #512). This article synthesizes the results from 13 papers within this Ambio Special Issue. Abiotic changes include glacial recession in the Altai Mountains, Russia; increased snow depth and hardness, permafrost warming, and increased growing season length in sub-arctic Sweden; drying of ponds in Greenland; increased nutrient availability in Alaskan tundra ponds, and warming at most locations studied. Biotic changes ranged from relatively minor plant community change at two sites in Greenland to moderate change in the Yukon, and to dramatic increases in shrub and tree density on Herschel Island, and in subarctic Sweden. The population of geese tripled at one site in northeast Greenland where biomass in non-grazed plots doubled. A model parameterized using results from a BTF study forecasts substantial declines in all snowbeds and increases in shrub tundra on Niwot Ridge, Colorado over the next century. In general, results support and provide improved capacities for validating experimental manipulation, remote sensing, and modeling studies.
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Affiliation(s)
- Terry V. Callaghan
- Royal Swedish Academy of Sciences, Lilla Frescativägen 4 A, 114 18 Stockholm, Sweden
- Department of Animal and Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN UK
| | - Craig E. Tweedie
- Department of Biology, The University of Texas at El Paso, 500 West University Ave, El Paso, TX 79968-0519 USA
| | - Jonas Åkerman
- Royal Swedish Academy of Sciences, PO Box 50005, 104 05 Stockholm, Sweden
| | | | - Johan Bergstedt
- IFM—Physics, Chemistry and Biology, Linköping University, 581 83 Linköping, Sweden
| | - Malcolm G. Butler
- Department of Biological Sciences, North Dakota State University, Fargo, ND 58108 USA
| | - Torben R. Christensen
- Department of Earth and Ecosystem Sciences, Division of Physical Geography and Ecosystem Analyses, Lund University, Sölvegatan 12, 223 62 Lund, Sweden
| | - Dorothy Cooley
- Department of Environment, Yukon Territorial Government, Dawson City, YT Canada
| | | | - Ryan K. Danby
- Department of Geography and School of Environmental Studies, Queen’s University, Kingston, ON K7L 3N6 Canada
| | - Fred J. A. Daniёls
- Institute of Biology and Biotechnology of Plants, Hindenburgplatz 55, 48149 Münster, Germany
| | - Johannes G. de Molenaar
- Gruttostraat 24, 4021EX Maurik,
The Netherlands
- Alterra, Wageningen University, Wageningen, The Netherlands
| | - Jan Dick
- Centre for Ecology & Hydrology, Penicuik, EH26 0QB UK
| | | | - Diane Ebert-May
- Department of Plant Biology, Michigan State University, 166 Plant Biology Building, East Lansing, MI 48824-1312 USA
| | | | | | - Henrik Hedenås
- Abisko Scientific Research Station, 981 07 Abisko, Sweden
| | - Greg. H. R. Henry
- Department of Geography, University of British Columbia, 1984 West Mall, Vancouver, BC V6T 1Z2 Canada
| | - David S. Hik
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9 Canada
| | - John E. Hobbie
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543 USA
| | - Elin J. Jantze
- Department of Physical Geography and Quaternary Geology, Stockholm University, Svante Arrhenius väg 8, 106 91 Stockholm, Sweden
| | | | - Cecilia Johansson
- Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36 Uppsala, Sweden
| | - Margareta Johansson
- Department of Earth and Ecosystem Sciences, Lund University, Sölvegatan 12, 223 62 Lund, Sweden
| | - David R. Johnson
- Department of Biology, The University of Texas at El Paso, 500 West University Ave, El Paso, TX 79968-0519 USA
| | - Jill F. Johnstone
- Department of Biology, University of Saskatchewan, Saskatoon, SK Canada
| | | | - Catherine Kennedy
- Department of Environment, Yukon Territorial Government, Whitehorse, YT Canada
| | - Alice J. Kenney
- Department of Zoology, University of British Columbia, Vancouver, BC Canada
| | - Frida Keuper
- Department of Systems Ecology, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands
| | - Saewan Koh
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9 Canada
| | - Charles J. Krebs
- Department of Zoology, University of British Columbia, Vancouver, BC Canada
| | - Hugues Lantuit
- Alfred Wegener Institute, Telegrafenberg A45, 14473 Potsdam, Germany
| | - Mark J. Lara
- Department of Biology, The University of Texas at El Paso, 500 West University Ave, El Paso, TX 79968-0519 USA
| | - David Lin
- Department of Biology, The University of Texas at El Paso, 500 West University Ave, El Paso, TX 79968-0519 USA
| | - Vanessa L. Lougheed
- Department of Biology, The University of Texas at El Paso, 500 West University Ave, El Paso, TX 79968-0519 USA
| | - Jesper Madsen
- Department of Arctic Environment, National Environmental Research Institute, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Nadya Matveyeva
- Department of Vegetation of the Far North, Komarov Botanical Institute, St. Petersburg, Russia
| | - Daniel C. McEwen
- Department of Biosciences, Minnesota State University Moorhead, Moorhead, MN 56563 USA
| | - Isla H. Myers-Smith
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2E9 Canada
| | - Yuriy K. Narozhniy
- Research Laboratory of Glacioclimatology, Tomsk State University, Tomsk, Russia
| | - Håkan Olsson
- Forest Resource Management, Swedish university of Agricultural Sciences, 901 83 Umeå, Sweden
| | - Veijo A. Pohjola
- Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36 Uppsala, Sweden
| | - Larry W. Price
- Department of Geography, Portland State University, Portland, OR USA
| | - Frank Rigét
- Department of Biosciences, Minnesota State University Moorhead, Moorhead, MN 56563 USA
| | | | | | - Mikkel Tamstorf
- Department of Biosciences, Minnesota State University Moorhead, Moorhead, MN 56563 USA
| | - Rik Van Bogaert
- Flanders Research Foundation, Egmontstraat 5, Brussels, Belgium
| | - Sandra Villarreal
- Department of Biology, The University of Texas at El Paso, 500 West University Ave, El Paso, TX 79968-0519 USA
| | - Patrick J. Webber
- Department of Plant Biology, Michigan State University, 166 Plant Biology Building, East Lansing, MI 48824-1312 USA
- P.O. Box 1380, Ranchos de Taos, NM 87557 USA
| | - Valeriy A. Zemtsov
- Hydrology Department, Faculty of Geology and Geography, Tomsk State University, 36 Lenin Avenue, Tomsk, Russia 634050
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Grosse G, Harden J, Turetsky M, McGuire AD, Camill P, Tarnocai C, Frolking S, Schuur EAG, Jorgenson T, Marchenko S, Romanovsky V, Wickland KP, French N, Waldrop M, Bourgeau-Chavez L, Striegl RG. Vulnerability of high-latitude soil organic carbon in North America to disturbance. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jg001507] [Citation(s) in RCA: 305] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Algar CK, Boudreau BP, Barry MA. Initial rise of bubbles in cohesive sediments by a process of viscoelastic fracture. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2010jb008133] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Grosse G, Romanovsky V, Jorgenson T, Anthony KW, Brown J, Overduin PP. Vulnerability and Feedbacks of Permafrost to Climate Change. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011eo090001] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Guido Grosse
- Geophysical Institute, University of Alaska Fairbanks, USA
| | | | | | | | | | - Pier Paul Overduin
- Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany
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Northern peatland initiation lagged abrupt increases in deglacial atmospheric CH4. Proc Natl Acad Sci U S A 2011; 108:4748-53. [PMID: 21368146 DOI: 10.1073/pnas.1013270108] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Peatlands are a key component of the global carbon cycle. Chronologies of peatland initiation are typically based on compiled basal peat radiocarbon (14C) dates and frequency histograms of binned calibrated age ranges. However, such compilations are problematic because poor quality 14C dates are commonly included and because frequency histograms of binned age ranges introduce chronological artefacts that bias the record of peatland initiation. Using a published compilation of 274 basal 14C dates from Alaska as a case study, we show that nearly half the 14C dates are inappropriate for reconstructing peatland initiation, and that the temporal structure of peatland initiation is sensitive to sampling biases and treatment of calibrated 14C dates. We present revised chronologies of peatland initiation for Alaska and the circumpolar Arctic based on summed probability distributions of calibrated 14C dates. These revised chronologies reveal that northern peatland initiation lagged abrupt increases in atmospheric CH4 concentration at the start of the Bølling-Allerød interstadial (Termination 1A) and the end of the Younger Dryas chronozone (Termination 1B), suggesting that northern peatlands were not the primary drivers of the rapid increases in atmospheric CH4. Our results demonstrate that subtle methodological changes in the synthesis of basal 14C ages lead to substantially different interpretations of temporal trends in peatland initiation, with direct implications for the role of peatlands in the global carbon cycle.
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