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  • 1. Aben, Ralf C. H.
    et al.
    Barros, Nathan
    van Donk, Ellen
    Frenken, Thijs
    Hilt, Sabine
    Kazanjian, Garabet
    Lamers, Leon P. M.
    Peeters, Edwin T. H. M.
    Roelofs, Jan G. M.
    de Senerpont Domis, Lisette N.
    Stephan, Susanne
    Velthuis, Mandy
    Van de Waal, Dedmer B.
    Wik, Martin
    Thornton, Brett F.
    Wilkinson, Jeremy
    DelSontro, Tonya
    Kosten, Sarian
    Cross continental increase in methane ebullition under climate change2017Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 8, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Methane (CH4) strongly contributes to observed global warming. As natural CH4 emissions mainly originate from wet ecosystems, it is important to unravel how climate change may affect these emissions. This is especially true for ebullition (bubble flux from sediments), a pathway that has long been underestimated but generally dominates emissions. Here we show a remarkably strong relationship between CH4 ebullition and temperature across a wide range of freshwater ecosystems on different continents using multi-seasonal CH4 ebullition data from the literature. As these temperature–ebullition relationships may have been affected by seasonal variation in organic matter availability, we also conducted a controlled year-round mesocosm experiment. Here 4 °C warming led to 51% higher total annual CH4 ebullition, while diffusion was not affected. Our combined findings suggest that global warming will strongly enhance freshwater CH4 emissions through a disproportional increase in ebullition (6–20% per 1 °C increase), contributing to global warming.

  • 2. Baccarini, Andrea
    et al.
    Karlsson, Linn
    Dommen, Josef
    Duplessis, Patrick
    Vüllers, Jutta
    Brooks, Ian M.
    Saiz-Lopez, Alfonso
    Salter, Matthew
    Tjernström, Michael
    Baltensperger, Urs
    Zieger, Paul
    Schmale, Julia
    Frequent new particle formation over the high Arctic pack ice by enhanced iodine emissions2020Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 11, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In the central Arctic Ocean the formation of clouds and their properties are sensitive to the availability of cloud condensation nuclei (CCN). The vapors responsible for new particle formation (NPF), potentially leading to CCN, have remained unidentified since the first aerosol measurements in 1991. Here, we report that all the observed NPF events from the Arctic Ocean 2018 expedition are driven by iodic acid with little contribution from sulfuric acid. Iodic acid largely explains the growth of ultrafine particles (UFP) in most events. The iodic acid concentration increases significantly from summer towards autumn, possibly linked to the ocean freeze-up and a seasonal rise in ozone. This leads to a one order of magnitude higher UFP concentration in autumn. Measurements of cloud residuals suggest that particles smaller than 30 nm in diameter can activate as CCN. Therefore, iodine NPF has the potential to influence cloud properties over the Arctic Ocean.

  • 3.
    Blume-Werry, Gesche
    et al.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Krab, Eveline J
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Olofsson, Johan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Sundqvist, Maja K.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Väisänen, Maria
    Klaminder, Jonatan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Invasive earthworms unlock arctic plant nitrogen limitation2020Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 11, nr 1, artikkel-id 1766Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Arctic plant growth is predominantly nitrogen (N) limited. This limitation is generally attributed to slow soil microbial processes due to low temperatures. Here, we show that arctic plant-soil N cycling is also substantially constrained by the lack of larger detritivores (earthworms) able to mineralize and physically translocate litter and soil organic matter. These new functions provided by earthworms increased shrub and grass N concentration in our common garden experiment. Earthworm activity also increased either the height or number of floral shoots, while enhancing fine root production and vegetation greenness in heath and meadow communities to a level that exceeded the inherent differences between these two common arctic plant communities. Moreover, these worming effects on plant N and greening exceeded reported effects of warming, herbivory and nutrient addition, suggesting that human spreading of earthworms may lead to substantial changes in the structure and function of arctic ecosystems. Arctic plant growth is predominantly nitrogen limited, where the slow nitrogen turnover in the soil is commonly attributed to the cold arctic climate. Here the authors show that the arctic plant-soil nitrogen cycling is also constrained by the lack of larger detritivores like earthworms.

    Fulltekst (pdf)
  • 4. Büntgen, Ulf
    et al.
    Wacker, Lukas
    Galván, J Diego
    Arnold, Stephanie
    Arseneault, Dominique
    Baillie, Michael
    Beer, Jürg
    Bernabei, Mauro
    Bleicher, Niels
    Boswijk, Gretel
    Bräuning, Achim
    Carrer, Marco
    Ljungqvist, Fredrik Charpentier
    Cherubini, Paolo
    Christl, Marcus
    Christie, Duncan A
    Clark, Peter W
    Cook, Edward R
    D'Arrigo, Rosanne
    Davi, Nicole
    Eggertsson, Ólafur
    Esper, Jan
    Fowler, Anthony M
    Gedalof, Ze'ev
    Gennaretti, Fabio
    Grießinger, Jussi
    Grissino-Mayer, Henri
    Grudd, Håkan
    Gunnarson, Björn E
    Hantemirov, Rashit
    Herzig, Franz
    Hessl, Amy
    Heussner, Karl-Uwe
    Jull, A J Timothy
    Kukarskih, Vladimir
    Kirdyanov, Alexander
    Kolář, Tomáš
    Krusic, Paul J
    Kyncl, Tomáš
    Lara, Antonio
    LeQuesne, Carlos
    Linderholm, Hans W
    Loader, Neil J
    Luckman, Brian
    Miyake, Fusa
    Myglan, Vladimir S
    Nicolussi, Kurt
    Oppenheimer, Clive
    Palmer, Jonathan
    Panyushkina, Irina
    Pederson, Neil
    Rybníček, Michal
    Schweingruber, Fritz H
    Seim, Andrea
    Sigl, Michael
    Churakova Sidorova, Olga
    Speer, James H
    Synal, Hans-Arno
    Tegel, Willy
    Treydte, Kerstin
    Villalba, Ricardo
    Wiles, Greg
    Wilson, Rob
    Winship, Lawrence J
    Wunder, Jan
    Yang, Bao
    Young, Giles H F
    Tree rings reveal globally coherent signature of cosmogenic radiocarbon events in 774 and 993 CE2018Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 9, nr 1, s. 3605-3605Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Though tree-ring chronologies are annually resolved, their dating has never been independently validated at the global scale. Moreover, it is unknown if atmospheric radiocarbon enrichment events of cosmogenic origin leave spatiotemporally consistent fingerprints. Here we measure the (14)C content in 484 individual tree rings formed in the periods 770-780 and 990-1000 CE. Distinct (14)C excursions starting in the boreal summer of 774 and the boreal spring of 993 ensure the precise dating of 44 tree-ring records from five continents. We also identify a meridional decline of 11-year mean atmospheric radiocarbon concentrations across both hemispheres. Corroborated by historical eye-witness accounts of red auroras, our results suggest a global exposure to strong solar proton radiation. To improve understanding of the return frequency and intensity of past cosmic events, which is particularly important for assessing the potential threat of space weather on our society, further annually resolved (14)C measurements are needed.

  • 5. Chang, Kuang-Yu
    et al.
    Riley, William J.
    Knox, Sara H.
    Jackson, Robert B.
    McNicol, Gavin
    Poulter, Benjamin
    Aurela, Mika
    Baldocchi, Dennis
    Bansal, Sheel
    Bohrer, Gil
    Campbell, David I.
    Cescatti, Alessandro
    Chu, Housen
    Delwiche, Kyle B.
    Desai, Ankur R.
    Euskirchen, Eugenie
    Friborg, Thomas
    Goeckede, Mathias
    Helbig, Manuel
    Hemes, Kyle S.
    Hirano, Takashi
    Iwata, Hiroki
    Kang, Minseok
    Keenan, Trevor
    Krauss, Ken W.
    Lohila, Annalea
    Mammarella, Ivan
    Mitra, Bhaskar
    Miyata, Akira
    Nilsson, Mats B.
    Noormets, Asko
    Oechel, Walter C.
    Papale, Dario
    Peichl, Matthias
    Reba, Michele L.
    Rinne, Janne
    Runkle, Benjamin R. K.
    Ryu, Youngryel
    Sachs, Torsten
    Schäfer, Karina V. R.
    Schmid, Hans Peter
    Shurpali, Narasinha
    Sonnentag, Oliver
    Tang, Angela C. I.
    Torn, Margaret S.
    Trotta, Carlo
    Tuittila, Eeva-Stiina
    Ueyama, Masahito
    Vargas, Rodrigo
    Vesala, Timo
    Windham-Myers, Lisamarie
    Zhang, Zhen
    Zona, Donatella
    Substantial hysteresis in emergent temperature sensitivity of global wetland CH4 emissions2021Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 12, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Wetland methane (CH4) emissions (FCH4) are important in global carbon budgets and climate change assessments. Currently, FCH4 projections rely on prescribed static temperature sensitivity that varies among biogeochemical models. Meta-analyses have proposed a consistent FCH4 temperature dependence across spatial scales for use in models; however, site-level studies demonstrate that FCH4 are often controlled by factors beyond temperature. Here, we evaluate the relationship between FCH4 and temperature using observations from the FLUXNET-CH4 database. Measurements collected across the globe show substantial seasonal hysteresis between FCH4 and temperature, suggesting larger FCH4 sensitivity to temperature later in the frost-free season (about 77% of site-years). Results derived from a machine-learning model and several regression models highlight the importance of representing the large spatial and temporal variability within site-years and ecosystem types. Mechanistic advancements in biogeochemical model parameterization and detailed measurements in factors modulating CH4 production are thus needed to improve global CH4 budget assessments.

  • 6. Emerson, Joanne B.
    et al.
    Varner, Ruth K.
    Wik, Martin
    Parks, Donovan H.
    Neumann, Rebecca B.
    Johnson, Joel E.
    Singleton, Caitlin M.
    Woodcroft, Ben J.
    Tollerson, Rodney
    Owusu-Dommey, Akosua
    Binder, Morgan
    Freitas, Nancy L.
    Crill, Patrick M.
    Saleska, Scott R.
    Tyson, Gene W.
    Rich, Virginia I.
    Diverse sediment microbiota shape methane emission temperature sensitivity in Arctic lakes2021Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 12, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Northern post-glacial lakes are significant, increasing sources of atmospheric carbon through ebullition (bubbling) of microbially-produced methane (CH4) from sediments. Ebullitive CH4 flux correlates strongly with temperature, reflecting that solar radiation drives emissions. However, here we show that the slope of the temperature-CH4 flux relationship differs spatially across two post-glacial lakes in Sweden. We compared these CH4 emission patterns with sediment microbial (metagenomic and amplicon), isotopic, and geochemical data. The temperature-associated increase in CH4 emissions was greater in lake middles—where methanogens were more abundant—than edges, and sediment communities were distinct between edges and middles. Microbial abundances, including those of CH4-cycling microorganisms and syntrophs, were predictive of porewater CH4 concentrations. Results suggest that deeper lake regions, which currently emit less CH4 than shallower edges, could add substantially to CH4 emissions in a warmer Arctic and that CH4 emission predictions may be improved by accounting for spatial variations in sediment microbiota.

  • 7. Hodgkins, Suzanne B.
    et al.
    Richardson, Curtis J.
    Dommain, René
    Wang, Hongjun
    Glaser, Paul H.
    Verbeke, Brittany
    Winkler, B. Rose
    Cobb, Alexander R.
    Rich, Virginia I.
    Missilmani, Malak
    Flanagan, Neal
    Ho, Mengchi
    Hoyt, Alison M.
    Harvey, Charles F.
    Vining, S. Rose
    Hough, Moira A.
    Moore, Tim R.
    Richard, Pierre J. H.
    De La Cruz, Florentino B.
    Toufaily, Joumana
    Hamdan, Rasha
    Cooper, William T.
    Chanton, Jeffrey P.
    Tropical peatland carbon storage linked to global latitudinal trends in peat recalcitrance2018Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 9, artikkel-id 3640Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation state and resulting recalcitrance. This recalcitrance allows peat to persist in the (sub)tropics despite warm temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable despite temperature increases up to 9 °C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats.

  • 8.
    Jakobsson, Martin
    et al.
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Hogan, Kelly A.
    Mayer, Larry A.
    Mix, Alan
    Jennings, Anne
    Stoner, Joe
    Eriksson, Björn
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Jerram, Kevin
    Mohammad, Rezwan
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    Pearce, Christof
    Reilly, Brendan
    Stranne, Christian
    Stockholms universitet, Institutionen för geologiska vetenskaper.
    The Holocene retreat dynamics and stability of Petermann Glacier in northwest Greenland2018Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 9, artikkel-id 2104Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Submarine glacial landforms in fjords are imprints of the dynamic behaviour of marine-terminating glaciers and are informative about their most recent retreat phase. Here we use detailed multibeam bathymetry to map glacial landforms in Petermann Fjord and Nares Strait, northwestern Greenland. A large grounding-zone wedge (GZW) demonstrates that Petermann Glacier stabilised at the fjord mouth for a considerable time, likely buttressed by an ice shelf. This stability was followed by successive backstepping of the ice margin down the GZW's retrograde backslope forming small retreat ridges to 680 m current depth (similar to 730-800 m palaeodepth). Iceberg ploughmarks occurring somewhat deeper show that thick, grounded ice persisted to these water depths before final breakup occurred. The palaeodepth limit of the recessional moraines is consistent with final collapse driven by marine ice cliff instability (MICI) with retreat to the next stable position located underneath the present Petermann ice tongue, where the seafloor is unmapped.

  • 9. Jakobsson, Martin
    et al.
    Nilsson, Johan
    Anderson, Leif
    Backman, Jan
    Bjork, Goran
    Cronin, Thomas M.
    Kirchner, Nina
    Koshurnikov, Andrey
    Mayer, Larry
    Noormets, Riko
    O'Regan, Matthew
    Stranne, Christian
    Ananiev, Roman
    Macho, Natalia Barrientos
    Cherniykh, Denis
    Coxall, Helen
    Eriksson, Bjorn
    Floden, Tom
    Gemery, Laura
    Gustafsson, Orjan
    Jerram, Kevin
    Johansson, Carina
    Khortov, Alexey
    Mohammad, Rezwan
    Semiletov, Igor
    Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation2016Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 7, artikkel-id 10365Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice-shelf groundings on bathymetric highs in the central Arctic Ocean, resurrecting the concept of an ice shelf extending over the entire central Arctic Ocean during at least one previous ice age. New and previously mapped glacial landforms together reveal flow of a spatially coherent, in some regions41-km thick, central Arctic Ocean ice shelf dated to marine isotope stage 6 (similar to 140 ka). Bathymetric highs were likely critical in the ice-shelf development by acting as pinning points where stabilizing ice rises formed, thereby providing sufficient back stress to allow ice shelf thickening.

  • 10. Koulakov, Ivan
    et al.
    Schlindwein, Vera
    Liu, Mingqi
    Gerya, Taras
    Jakovlev, Andrey
    Ivanov, Aleksey
    Low-degree mantle melting controls the deep seismicity and explosive volcanism of the Gakkel Ridge2022Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 13, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The world’s strongest known spreading-related seismicity swarm occurred in 1999 in a segment of the Gakkel Ridge located at 85°E as a consequence of an effusive-explosive submarine volcanic eruption. The data of a seismic network deployed on ice floes were used to locate hundreds of local earthquakes down to ∼25 km depth and to build a seismic tomography model under the volcanic area. Here we show the seismicity and the distribution of seismic velocities together with the 3D magmatic-thermomechanical numerical model, which demonstrate how a magma reservoir under the Gakkel Ridge may form, rise and trigger volcanic eruptions in the rift valley. The ultraslow spreading rates with low mantle potential temperatures appear to be a critical factor in the production of volatile-rich, low-degree mantle melts that are focused toward the magma reservoirs within narrow magmatic sections. The degassing of these melts is the main cause of the explosive submarine eruptions.

  • 11. Mekhaldi, Florian
    et al.
    Muscheler, Raimund
    Adolphi, Florian
    Aldahan, Ala
    Beer, Juerg
    McConnell, Joseph R.
    Possnert, Goran
    Sigl, Michael
    Svensson, Anders
    Synal, Hans-Arno
    Welten, Kees C.
    Woodruff, Thomas E.
    Multiradionuclide evidence for the solar origin of the cosmic-ray events of AD 774/5 and 993/42015Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 6, artikkel-id 8611Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The origin of two large peaks in the atmospheric radiocarbon (C-14) concentration at AD 774/5 and 993/4 is still debated. There is consensus, however, that these features can only be explained by an increase in the atmospheric C-14 production rate due to an extraterrestrial event. Here we provide evidence that these peaks were most likely produced by extreme solar events, based on several new annually resolved Be-10 measurements from both Arctic and Antarctic ice cores. Using ice core Cl-36 data in pair with Be-10, we further show that these solar events were characterized by a very hard energy spectrum with high fluxes of solar protons with energy above 100MeV. These results imply that the larger of the two events (AD 774/5) was at least five times stronger than any instrumentally recorded solar event. Our findings highlight the importance of studying the possibility of severe solar energetic particle events.

  • 12.
    Olid, Carolina
    et al.
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Rodellas, Valentí
    Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, Bellaterra, Spain.
    Rocher-Ros, Gerard
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Garcia-Orellana, Jordi
    Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, Bellaterra, Spain; Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, Spain.
    Diego-Feliu, Marc
    Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, Bellaterra, Spain; Departament de Física, Universitat Autònoma de Barcelona, Bellaterra, Spain; Department of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Barcelona, Spain; Associated Unit: Hydrogeology Group, UPC-CSIC, Barcelona, Spain.
    Alorda-Kleinglass, Aaron
    Institut de Ciència i Tecnologia Ambientals, Universitat Autònoma de Barcelona, Bellaterra, Spain.
    Bastviken, David
    Department of Thematic Studies—Environmental Change, Linköping University, Linköping, Sweden.
    Karlsson, Jan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Groundwater discharge as a driver of methane emissions from Arctic lakes2022Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 13, nr 1, artikkel-id 3667Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lateral CH4 inputs to Arctic lakes through groundwater discharge could be substantial and constitute an important pathway that links CH4 production in thawing permafrost to atmospheric emissions via lakes. Yet, groundwater CH4 inputs and associated drivers are hitherto poorly constrained because their dynamics and spatial variability are largely unknown. Here, we unravel the important role and drivers of groundwater discharge for CH4 emissions from Arctic lakes. Spatial patterns across lakes suggest groundwater inflows are primarily related to lake depth and wetland cover. Groundwater CH4 inputs to lakes are higher in summer than in autumn and are influenced by hydrological (groundwater recharge) and biological drivers (CH4 production). This information on the spatial and temporal patterns on groundwater discharge at high northern latitudes is critical for predicting lake CH4 emissions in the warming Arctic, as rising temperatures, increasing precipitation, and permafrost thawing may further exacerbate groundwater CH4 inputs to lakes.

  • 13. Patzner, Monique S.
    et al.
    Mueller, Carsten W.
    Malusova, Miroslava
    Baur, Moritz
    Nikeleit, Verena
    Scholten, Thomas
    Hoeschen, Carmen
    Byrne, James M.
    Borch, Thomas
    Kappler, Andreas
    Bryce, Casey
    Iron mineral dissolution releases iron and associated organic carbon during permafrost thaw2020Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 11, nr 1, artikkel-id 6329Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It has been shown that reactive soil minerals, specifically iron(III) (oxyhydr)oxides, can trap organic carbon in soils overlying intact permafrost, and may limit carbon mobilization and degradation as it is observed in other environments. However, the use of iron(III)-bearing minerals as terminal electron acceptors in permafrost environments, and thus their stability and capacity to prevent carbon mobilization during permafrost thaw, is poorly understood. We have followed the dynamic interactions between iron and carbon using a space-for-time approach across a thaw gradient in Abisko (Sweden), where wetlands are expanding rapidly due to permafrost thaw. We show through bulk (selective extractions, EXAFS) and nanoscale analysis (correlative SEM and nanoSIMS) that organic carbon is bound to reactive Fe primarily in the transition between organic and mineral horizons in palsa underlain by intact permafrost (41.8 ± 10.8 mg carbon per g soil, 9.9 to 14.8% of total soil organic carbon). During permafrost thaw, water-logging and O2 limitation lead to reducing conditions and an increase in abundance of Fe(III)-reducing bacteria which favor mineral dissolution and drive mobilization of both iron and carbon along the thaw gradient. By providing a terminal electron acceptor, this rusty carbon sink is effectively destroyed along the thaw gradient and cannot prevent carbon release with thaw.

  • 14. Sproson, Adam D.
    et al.
    Yokoyama, Yusuke
    Miyairi, Yosuke
    Aze, Takahiro
    Totten, Rebecca L.
    Holocene melting of the West Antarctic Ice Sheet driven by tropical Pacific warming2022Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 13, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The primary Antarctic contribution to modern sea-level rise is glacial discharge from the Amundsen Sea sector of the West Antarctic Ice Sheet. The main processes responsible for ice mass loss include: (1) ocean-driven melting of ice shelves by upwelling of warm water onto the continental shelf; and (2) atmospheric-driven surface melting of glaciers along the Antarctic coast. Understanding the relative influence of these processes on glacial stability is imperative to predicting sea-level rise. Employing a beryllium isotope-based reconstruction of ice-shelf history, we demonstrate that glaciers flowing into the Amundsen Sea Embayment underwent melting and retreat between 9 and 6 thousand years ago. Despite warm ocean water influence, this melting event was mainly forced by atmospheric circulation changes over continental West Antarctica, linked via a Rossby wave train to tropical Pacific Ocean warming. This millennial-scale glacial history may be used to validate contemporary ice-sheet models and improve sea-level projections.

  • 15. Tesi, T.
    et al.
    Muschitiello, F.
    Smittenberg, R. H.
    Jakobsson, M.
    Vonk, J. E.
    Hill, P.
    Andersson, A.
    Kirchner, N.
    Noormets, R.
    Dudarev, O.
    Semiletov, I.
    Gustafsson, O.
    Massive remobilization of permafrost carbon during post-glacial warming2016Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    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.

  • 16. Thomas, H. J. D.
    et al.
    Bjorkman, A. D.
    Myers-Smith, I. H.
    Elmendorf, S. C.
    Kattge, J.
    Diaz, S.
    Vellend, M.
    Blok, D.
    Cornelissen, J. H. C.
    Forbes, B. C.
    Henry, G. H. R.
    Hollister, R. D.
    Normand, S.
    Prevey, J. S.
    Rixen, C.
    Schaepman-Strub, G.
    Wilmking, M.
    Wipf, S.
    Cornwell, W. K.
    Beck, P. S. A.
    Georges, D.
    Goetz, S. J.
    Guay, K. C.
    Ruger, N.
    Soudzilovskaia, N. A.
    Spasojevic, M. J.
    Alatalo, J. M.
    Alexander, H. D.
    Anadon-Rosell, A.
    Angers-Blondin, S.
    te Beest, Mariska
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Berner, L. T.
    Bjoerk, R. G.
    Buchwal, A.
    Buras, A.
    Carbognani, M.
    Christie, K. S.
    Collier, L. S.
    Cooper, E. J.
    Elberling, B.
    Eskelinen, A.
    Frei, E. R.
    Grau, O.
    Grogan, P.
    Hallinger, M.
    Heijmans, M. M. P. D.
    Hermanutz, L.
    Hudson, J. M. G.
    Johnstone, J. F.
    Huelber, K.
    Iturrate-Garcia, M.
    Iversen, C. M.
    Jaroszynska, F.
    Kaarlejarvi, E.
    Kulonen, A.
    Lamarque, L. J.
    Lantz, T. C.
    Levesque, E.
    Little, C. J.
    Michelsen, A.
    Milbau, A.
    Nabe-Nielsen, J.
    Nielsen, S. S.
    Ninot, J. M.
    Oberbauer, S. F.
    Olofsson, Johan
    Umeå universitet, Institutionen för ekologi, miljö och geovetenskap.
    Onipchenko, V. G.
    Petraglia, A.
    Rumpf, S. B.
    Shetti, R.
    Speed, J. D. M.
    Suding, K. N.
    Tape, K. D.
    Tomaselli, M.
    Trant, A. J.
    Treier, U. A.
    Tremblay, M.
    Venn, S. E.
    Vowles, T.
    Weijers, S.
    Wookey, P. A.
    Zamin, T. J.
    Bahn, M.
    Blonder, B.
    van Bodegom, P. M.
    Bond-Lamberty, B.
    Campetella, G.
    Cerabolini, B. E. L.
    Chapin, F. S. , I I I
    Craine, J. M.
    Dainese, M.
    Green, W. A.
    Jansen, S.
    Kleyer, M.
    Manning, P.
    Niinemets, U.
    Onoda, Y.
    Ozinga, W. A.
    Penuelas, J.
    Poschlod, P.
    Reich, P. B.
    Sandel, B.
    Schamp, B. S.
    Sheremetiev, S. N.
    de Vries, F. T.
    Global plant trait relationships extend to the climatic extremes of the tundra biome2020Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 11, nr 1, artikkel-id 1351Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world.

    Fulltekst (pdf)
  • 17. Winiger, P.
    et al.
    Andersson, A.
    Eckhardt, S.
    Stohl, A.
    Gustafsson, O.
    The sources of atmospheric black carbon at a European gateway to the Arctic2016Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 7Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Black carbon (BC) aerosols from incomplete combustion of biomass and fossil fuel contribute to Arctic climate warming. Models-seeking to advise mitigation policy-are challenged in reproducing observations of seasonally varying BC concentrations in the Arctic air. Here we compare year-round observations of BC and its delta C-13/Delta C-14-diagnosed sources in Arctic Scandinavia, with tailored simulations from an atmospheric transport model. The model predictions for this European gateway to the Arctic are greatly improved when the emission inventory of anthropogenic sources is amended by satellite-derived estimates of BC emissions from fires. Both BC concentrations (R-2 = 0.89, P < 0.05) and source contributions (R-2 = 0.77, P < 0.05) are accurately mimicked and linked to predominantly European emissions. This improved model skill allows for more accurate assessment of sources and effects of BC in the Arctic, and a more credible scientific underpinning of policy efforts aimed at efficiently reducing BC emissions reaching the European Arctic.

  • 18. Zhang, Hui
    et al.
    Väliranta, Minna
    Swindles, Graeme T.
    Aquino-López, Marco A.
    Mullan, Donal
    Tan, Ning
    Amesbury, Matthew
    Babeshko, Kirill V.
    Bao, Kunshan
    Bobrov, Anatoly
    Chernyshov, Viktor
    Davies, Marissa A.
    Diaconu, Andrei-Cosmin
    Feurdean, Angelica
    Finkelstein, Sarah A.
    Garneau, Michelle
    Guo, Zhengtang
    Jones, Miriam C.
    Kay, Martin
    Klein, Eric S.
    Lamentowicz, Mariusz
    Magnan, Gabriel
    Marcisz, Katarzyna
    Mazei, Natalia
    Mazei, Yuri
    Payne, Richard
    Pelletier, Nicolas
    Piilo, Sanna R.
    Pratte, Steve
    Roland, Thomas
    Saldaev, Damir
    Shotyk, William
    Sim, Thomas G.
    Sloan, Thomas J.
    Słowiński, Michał
    Talbot, Julie
    Taylor, Liam
    Tsyganov, Andrey N.
    Wetterich, Sebastian
    Xing, Wei
    Zhao, Yan
    Recent climate change has driven divergent hydrological shifts in high-latitude peatlands2022Inngår i: Nature Communications, E-ISSN 2041-1723, Vol. 13, nr 1Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    High-latitude peatlands are changing rapidly in response to climate change, including permafrost thaw. Here, we reconstruct hydrological conditions since the seventeenth century using testate amoeba data from 103 high-latitude peat archives. We show that 54% of the peatlands have been drying and 32% have been wetting over this period, illustrating the complex ecohydrological dynamics of high latitude peatlands and their highly uncertain responses to a warming climate.

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