Author: "Casper T. Christiansen" / Topic: environmental science - Searchworks@Jio Institute Digital Library Search Results

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1. Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter

Author: Scott F. Lamoureux, Casper T. Christiansen, Julien Fouché, Melissa J. Lafrenière, Paul Grogan, Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro), Queen's University [Kingston, Canada], Center for Permafrost (CENPERM), Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)-Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), This research was funded by the Natural Sciences and Engineering Research Council (NSERC) Discovery Frontiers ADAPT program, the ArcticNet Network of Centres of Excellence, and NSERC Discovery grants to, Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro - Montpellier SupAgro, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)-Faculty of Science [Copenhagen], and University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)
Subjects: Cryospheric science, 010504 meteorology & atmospheric sciences, [SDV]Life Sciences [q-bio], Science, General Physics and Astronomy, 010501 environmental sciences, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, Permafrost, 01 natural sciences, Article, General Biochemistry, Genetics and Molecular Biology, Carbon cycle, Dissolved organic carbon, chemical composition, Organic matter, lcsh:Science, 0105 earth and related environmental sciences, watershed, chemistry.chemical_classification, Multidisciplinary, Soil organic matter, General Chemistry, 15. Life on land, dissolved organic matter, dissolved organic carbon, Active layer, ammonium, chemistry, Arctic, 13. Climate action, Environmental chemistry, Soil water, Environmental science, lcsh:Q, permafrost
Abstract: Permafrost degradation may lead to mobilization of carbon and nutrients and enhance microbial processing rates of previously frozen organic matter. Although the pool size and chemical composition of dissolved organic matter (DOM) are fundamental determinants of the carbon cycle in Arctic watersheds, its source within the seasonally thawing active layer and the underlying permafrost remains largely uncharacterized. Here, we used 25 soil cores that extended down into the permafrost from nine sites across Arctic Canada to quantify dissolved organic carbon (DOC) and nitrogen stocks, and to characterize DOM optical properties. Organic permafrost stores 5–7 times more DOC and ammonium than the active layer and mineral permafrost. Furthermore, the permafrost layers contain substantial low molecular weight DOM with low aromaticity suggesting high biodegradability. We conclude that soil organic matter stoichiometry and cryogenic processes determine permafrost DOM chemistry, and that thawing will mobilize large amounts of labile DOC and ammonium into Arctic watersheds., Arctic warming leads to permafrost thaw and release of previously frozen organic matter and nutrients, but characterization of these pools is lacking. Here the authors use soil cores across Northern Canada to investigate dissolved organic matter and nitrogen stored in permafrost soils.
Published: 2020
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2. Explicitly modelling microtopography in permafrost landscapes in a land-surface model (JULES vn5.4_microtopography)

Author: Hanna Lee, Eleanor J. Burke, Casper T. Christiansen, Heather Rumbold, Noah Smith, Inge H. J. Althuizen, Kjetil Schanke Aas, Julia Boike, Sarah Chadburn, Bernd Etzelmüller, Thomas Friborg, Sebastian Westermann, and Rachael Turton
Subjects: Water flow, Mire, Snowmelt, Environmental science, Soil science, Palsa, Permafrost, Snow, Surface runoff, Water content
Abstract: Microtopography can be a key driver of heterogeneity in the ground thermal and hydrological regime of permafrost landscapes. In turn, this heterogeneity can influence plant communities, methane fluxes and the initiation of abrupt thaw processes. Here we have implemented a two-tile representation of microtopography in JULES (the Joint UK Land Environment Simulator), where tiles are representative of repeating patterns of elevation difference. We evaluate the model against available spatially resolved observations at four sites, gauge the importance of explicitly representing microtopography for modelling methane emissions and quantify the relative importance of model processes and the model’s sensitivity its parameters. Tiles are coupled by lateral flows of water, heat and redistribution of snow. A surface water store is added to represent ponding. The model is parametrised using characteristic dimensions of landscape features at sites. Simulations are performed of two Siberian polygon sites, Samoylov and Kytalyk, and two Scandinavian palsa sites, Stordalen and Iškoras. The model represents the observed differences between greater snow depth in hollows vs raised areas well. The model also improves soil moisture for hollows vs the non-tiled configuration (‘standard JULES’) though the raised tile remains drier than observed. For the two palsa sites, it is found that drainage needs to be impeded from the lower tile, representing the non-permafrost mire, to achieve the observed soil saturation. This demonstrates the need for the landscape-scale drainage to be correctly modelled. Causes of moisture heterogeneity between tiles are decreased runoff from the low tile, differences in snowmelt, and high to low-tile water flow. Unsaturated flows between tiles are negligible, suggesting the adequacy of simpler water-table based models of lateral flow in wetland environments. The modelled differences in snow depths and soil moistures between tiles result in the lower tile soil temperatures being warmer for palsa sites. When comparing the soil temperatures for July at 20 cm depth, the difference in temperature between tiles, or ‘temperature splitting’, is smaller than observed (3.2 vs 5.5 °C). The mean temperature of the two tiles remains approximately unchanged (+0.4 °C) vs standard JULES, and lower than observations. Polygons display small (0.2 °C) to zero temperature splitting, in agreement with observations. Consequently, methane fluxes are near identical (+0 to 9 %) to those for standard JULES for polygons, though can be greater than standard JULES for palsa sites (+10 to 49 %). Through a sensitivity analysis we identify the parameters resulting in the greatest uncertainty in modelled temperature. We find that at the sites tested, varying the parameters can result in the modelled July temperature splitting being at most 0.9 or 3 °C larger than observed for palsa or polygon sites respectively. Varying the palsa elevation between 0.5 and 3 m has little effect on modelled soil temperatures, showing that having only two tiles can still be a valid representation of sites with a large variability of palsa elevations. Lateral conductive fluxes, while small, reduce the temperature splitting by ~1 °C, and correspond to the order of observed lateral degradation rates in peat plateau regions, indicating possible application in an area-based thaw model.
Published: 2021
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3. Effects of Climate and Atmospheric Nitrogen Deposition on Early to Mid-Term Stage Litter Decomposition Across Biomes

Author: TaeOh Kwon, Hideaki Shibata, Sebastian Kepfer-Rojas, Inger K. Schmidt, Klaus S. Larsen, Claus Beier, Björn Berg, Kris Verheyen, Jean-Francois Lamarque, Frank Hagedorn, Nico Eisenhauer, Ika Djukic, TeaComposition Network, Inger Kappel Schmidt, Klaus Steenberg Larsen, Jean Francois Lamarque, Adriano Caliman, Alain Paquette, Alba Gutiérrez-Girón, Alessandro Petraglia, Algirdas Augustaitis, Amélie Saillard, Ana Carolina Ruiz-Fernández, Ana I. Sousa, Ana I. Lillebø, Anderson da Rocha Gripp, Andrea Lamprecht, Andreas Bohner, André-Jean Francez, Andrey Malyshev, Andrijana Andrić, Angela Stanisci, Anita Zolles, Anna Avila, Anna-Maria Virkkala, Anne Probst, Annie Ouin, Anzar A. Khuroo, Arne Verstraeten, Artur Stefanski, Aurora Gaxiola, Bart Muys, Beatriz Gozalo, Bernd Ahrends, Bo Yang, Brigitta Erschbamer, Carmen Eugenia Rodríguez Ortíz, Casper T. Christiansen, Céline Meredieu, Cendrine Mony, Charles Nock, Chiao-Ping Wang, Christel Baum, Christian Rixen, Christine Delire, Christophe Piscart, Christopher Andrews, Corinna Rebmann, Cristina Branquinho, Dick Jan, Dirk Wundram, Dušanka Vujanović, E. Carol Adair, Eduardo Ordóñez-Regil, Edward R. Crawford, Elena F. Tropina, Elisabeth Hornung, Elli Groner, Eric Lucot, Esperança Gacia, Esther Lévesque, Evanilde Benedito, Evgeny A. Davydov, Fábio Padilha Bolzan, Fernando T. Maestre, Florence Maunoury-Danger, Florian Kitz, Florian Hofhansl, Flurin Sutter, Francisco de Almeida Lobo, Franco Leadro Souza, Franz Zehetner, Fulgence Kouamé Koffi, Georg Wohlfahrt, Giacomo Certini, Gisele Daiane Pinha, Grizelle González, Guylaine Canut, Harald Pauli, Héctor A. Bahamonde, Heike Feldhaar, Heinke Jäger, Helena Cristina Serrano, Hélène Verheyden, Helge Bruelheide, Henning Meesenburg, Hermann Jungkunst, Hervé Jactel, Hiroko Kurokawa, Ian Yesilonis, Inara Melece, Inge van Halder, Inmaculada García Quirós, István Fekete, Ivika Ostonen, Jana Borovská, Javier Roales, Jawad Hasan Shoqeir, Jean-Christophe Lata, Jean-Luc Probst, Jeyanny Vijayanathan, Jiri Dolezal, Joan-Albert Sanchez-Cabeza, Joël Merlet, John Loehr, Jonathan von Oppen, Jörg Löffler, José Luis Benito Alonso, José-Gilberto Cardoso-Mohedano, Josep Peñuelas, Joseph C. Morina, Juan Darío Quinde, Juan J. Jiménez, Juha M. Alatalo, Julia Seeber, Julia Kemppinen, Jutta Stadler, Kaie Kriiska, Karel Van den Meersche, Karibu Fukuzawa, Katalin Szlavecz, Katalin Juhos, Katarína Gerhátová, Kate Lajtha, Katie Jennings, Katja Tielbörger, Kazuhiko Hoshizaki, Ken Green, Klaus Steinbauer, Laryssa Pazianoto, Laura Dienstbach, Laura Yahdjian, Laura J. Williams, Laurel Brigham, Lee Hanna, Liesbeth van den Brink, Lindsey Rustad, Lourdes Morillas, Luciana Silva Carneiro, Luciano Di Martino, Luis Villar, Luísa Alícida Fernandes Tavares, Madison Morley, Manuela Winkler, Marc Lebouvier, Marcello Tomaselli, Marcus Schaub, Maria Glushkova, Maria Guadalupe Almazan Torres, Marie-Anne de Graaff, Marie-Noëlle Pons, Marijn Bauters, Marina Mazón, Mark Frenzel, Markus Wagner, Markus Didion, Maroof Hamid, Marta Lopes, Martha Apple, Martin Weih, Matej Mojses, Matteo Gualmini, Matthew Vadeboncoeur, Michael Bierbaumer, Michael Danger, Michael Scherer-Lorenzen, Michal Růžek, Michel Isabellon, Michele Di Musciano, Michele Carbognani, Miglena Zhiyanski, Mihai Puşcaş, Milan Barna, Mioko Ataka, Miska Luoto, Mohammed H. Alsafaran, Nadia Barsoum, Naoko Tokuchi, Nathalie Korboulewsky, Nicolas Lecomte, Nina Filippova, Norbert Hölzel, Olga Ferlian, Oscar Romero, Osvaldo Pinto-Jr, Pablo Peri, Pavel Dan Turtureanu, Peter Haase, Peter Macreadie, Peter B. Reich, Petr Petřík, Philippe Choler, Pierre Marmonier, Quentin Ponette, Rafael Dettogni Guariento, Rafaella Canessa, Ralf Kiese, Rebecca Hewitt, Robert Weigel, Róbert Kanka, Roberto Cazzolla Gatti, Rodrigo Lemes Martins, Romà Ogaya, Romain Georges, Rosario G. Gavilán, Sally Wittlinger, Sara Puijalon, Satoshi Suzuki, Schädler Martin, Schmidt Anja, Sébastien Gogo, Silvio Schueler, Simon Drollinger, Simone Mereu, Sonja Wipf, Stacey Trevathan-Tackett, Stefan Stoll, Stefan Löfgren, Stefan Trogisch, Steffen Seitz, Stephan Glatzel, Susanna Venn, Sylvie Dousset, Taiki Mori, Takanori Sato, Takuo Hishi, Tatsuro Nakaji, Theurillat Jean-Paul, Thierry Camboulive, Thomas Spiegelberger, Thomas Scholten, Thomas J. Mozdzer, Till Kleinebecker, Tomáš Rusňák, Tshililo Ramaswiela, Tsutom Hiura, Tsutomu Enoki, Tudor-Mihai Ursu, Umberto Morra di Cella, Ute Hamer, Valentin Klaus, Valter Di Cecco, Vanessa Rego, Veronika Fontana, Veronika Piscová, Vincent Bretagnolle, Vincent Maire, Vinicius Farjalla, Vittoz Pascal, Wenjun Zhou, Wentao Luo, William Parker, Yasuhiro Utsumi, Yuji Kominami, Zsolt Kotroczó, Zsolt Tóth, Field Science Center for Northern Biosphere, Hokkaido University [Sapporo, Japan], Department of Geosciences and Natural Resource Management [Copenhagen] (IGN), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Department of Forest Sciences [Helsinki], Faculty of Agriculture and Forestry [Helsinki], University of Helsinki-University of Helsinki, Department of Forest and Water Management, Forest & Nature Lab, Universiteit Gent = Ghent University [Belgium] (UGENT), National Center for Atmospheric Research [Boulder] (NCAR), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, German Centre for Integrative Biodiversity Research (iDiv), Institute of Biology, Leipzig University, Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Zone Atelier du Bassin de la Moselle [LTSER France] (ZAM), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes forestiers (UR EFNO), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Équipe 3 - Écologie, Évolution, Écosystemes Souterrains (E3S), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)-Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.)-Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS), ZABR UMR 5023 VILLEURBANNE CEDEX, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Équipe 2 - Écologie Végétale et Zones Humides (EVZH), Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Repositório da Universidade de Lisboa, Centre National de la Recherche Scientifique - CNRS (FRANCE), University of Helsinki (FINLAND), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Hokkaido University (JAPAN), German Centre for Integrative Biodiversity Research - iDiv (GERMANY), Universität Leipzig (GERMANY), National Center for Atmospheric Research - NCAR (UNITED STATES), Forschungsanstalt für Wald, Schnee und Landschaft - WSL (SWITZERLAND), Tea composition (SWITZERLAND), Universiteit Gent - UGENT (BELGIUM), University of Copenhagen - UCPH (DENMARK), Laboratoire Ecologie fonctionnelle et Environnement - EcoLab (Toulouse, France), University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH), Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Universiteit Gent = Ghent University (UGENT), Leipzig University, Université de Rennes (UR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Unité de recherche Comportement et Ecologie de la Faune Sauvage (CEFS), Muys, Bart, Department of Forest Sciences, Lammi Biological Station, Biological stations, Department of Geosciences and Geography, Helsinki Institute of Sustainability Science (HELSUS), BioGeoClimate Modelling Lab, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Kwon T., Shibata H., Kepfer-Rojas S., Schmidt I.K., Larsen K.S., Beier C., Berg B., Verheyen K., Lamarque J.-F., Hagedorn F., Eisenhauer N., Djukic I., Caliman A., Paquette A., Gutierrez-Giron A., Petraglia A., Augustaitis A., Saillard A., Ruiz-Fernandez A.C., Sousa A.I., Lillebo A.I., Da Rocha Gripp A., Lamprecht A., Bohner A., Francez A.-J., Malyshev A., Andric A., Stanisci A., Zolles A., Avila A., Virkkala A.-M., Probst A., Ouin A., Khuroo A.A., Verstraeten A., Stefanski A., Gaxiola A., Muys B., Gozalo B., Ahrends B., Yang B., Erschbamer B., Rodriguez Ortiz C.E., Christiansen C.T., Meredieu C., Mony C., Nock C., Wang C.-P., Baum C., Rixen C., Delire C., Piscart C., Andrews C., Rebmann C., Branquinho C., Jan D., Wundram D., Vujanovic D., Adair E.C., Ordonez-Regil E., Crawford E.R., Tropina E.F., Hornung E., Groner E., Lucot E., Gacia E., Levesque E., Benedito E., Davydov E.A., Bolzan F.P., Maestre F.T., Maunoury-Danger F., Kitz F., Hofhansl F., Hofhansl G., De Almeida Lobo F., Souza F.L., Zehetner F., Koffi F.K., Wohlfahrt G., Certini G., Pinha G.D., Gonzlez G., Canut G., Pauli H., Bahamonde H.A., Feldhaar H., Jger H., Serrano H.C., Verheyden H., Bruelheide H., Meesenburg H., Jungkunst H., Jactel H., Kurokawa H., Yesilonis I., Melece I., Van Halder I., Quiros I.G., Fekete I., Ostonen I., Borovsk J., Roales J., Shoqeir J.H., Jean-Christophe Lata J., Probst J.-L., Vijayanathan J., Dolezal J., Sanchez-Cabeza J.-A., Merlet J., Loehr J., Von Oppen J., Loffler J., Benito Alonso J.L., Cardoso-Mohedano J.-G., Penuelas J., Morina J.C., Quinde J.D., Jimnez J.J., Alatalo J.M., Seeber J., Kemppinen J., Stadler J., Kriiska K., Van Den Meersche K., Fukuzawa K., Szlavecz K., Juhos K., Gerhtov K., Lajtha K., Jennings K., Jennings J., Ecology P., Hoshizaki K., Green K., Steinbauer K., Pazianoto L., Dienstbach L., Yahdjian L., Williams L.J., Brigham L., Hanna L., Hanna H., Rustad L., Morillas L., Silva Carneiro L., Di Martino L., Villar L., Fernandes Tavares L.A., Morley M., Winkler M., Lebouvier M., Tomaselli M., Schaub M., Glushkova M., Torres M.G.A., De Graaff M.-A., Pons M.-N., Bauters M., Mazn M., Frenzel M., Wagner M., Didion M., Hamid M., Lopes M., Apple M., Weih M., Mojses M., Gualmini M., Vadeboncoeur M., Bierbaumer M., Danger M., Scherer-Lorenzen M., Ruek M., Isabellon M., Di Musciano M., Carbognani M., Zhiyanski M., Puca M., Barna M., Ataka M., Luoto M., H. Alsafaran M., Barsoum N., Tokuchi N., Korboulewsky N., Lecomte N., Filippova N., Hlzel N., Ferlian O., Romero O., Pinto-Jr O., Peri P., Dan Turtureanu P., Haase P., Macreadie P., Reich P.B., Petk P., Choler P., Marmonier P., Ponette Q., Dettogni Guariento R., Canessa R., Kiese R., Hewitt R., Weigel R., Kanka R., Cazzolla Gatti R., Martins R.L., Ogaya R., Georges R., Gaviln R.G., Wittlinger S., Puijalon S., Suzuki S., Martin S., Anja S., Gogo S., Schueler S., Drollinger S., Mereu S., Wipf S., Trevathan-Tackett S., Stoll S., Lfgren S., Trogisch S., Seitz S., Glatzel S., Venn S., Dousset S., Mori T., Sato T., Hishi T., Nakaji T., Jean-Paul T., Camboulive T., Spiegelberger T., Scholten T., Mozdzer T.J., Kleinebecker T., Runk T., Ramaswiela T., Hiura T., Enoki T., Ursu T.-M., Di Cella U.M., Hamer U., Klaus V., Di Cecco V., Rego V., Fontana V., Piscov V., Bretagnolle V., Maire V., Farjalla V., Pascal V., Zhou W., Luo W., Parker W., Parker P., Kominam Y., Kotrocz Z., and Utsumi Y.
Subjects: 010504 meteorology & atmospheric sciences, tea bag, Green tea, Rooibos tea, litter decomposition, carbon turnover, nitrogen deposition, TeaComposition initiative, Biome, SOIL MICROBIAL COMMUNITIES, tea bag, Green tea, Rooibos tea, litter decomposition, carbon turnover, nitrogen deposition, TeaComposition initiative, Carbon turnover, Nitrogen deposition -TeaComposition initiative, Suelo, Flora Microbiana, 01 natural sciences, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, GE1-350, Ecosistemas Terrestres, Global and Planetary Change, Nutrient Cycling, Té Verde, Nitrogen deposition - TeaComposition initiative, [SDE.IE]Environmental Sciences/Environmental Engineering, Forestry, Biomas, [SDE]Environmental Sciences, Terrestrial ecosystem, [SDV.TOX.ECO]Life Sciences [q-bio]/Toxicology/Ecotoxicology, Biologie, Nitrogen, [SDE.MCG]Environmental Sciences/Global Changes, [SDV.SA.SDS]Life Sciences [q-bio]/Agricultural sciences/Soil study, Animal science, LEAF, ORGANIC-CARBON, Carbono, RATES, [SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, climate, Escala Global, Nature and Landscape Conservation, Nutrientes, forests, Ecologie, Environnement, Science & Technology, 15. Life on land, worldwide experiment, [SDE.ES]Environmental Sciences/Environmental and Society, Carbon, Biology and Microbiology, Agriculture and Soil Science, Precipitación Atmosférica, Cambio Climático, Litter, 0401 agriculture, forestry, and fisheries, Tea Composition initiative, N-deposition, Deposition (chemistry), Global Scale, RESPONSES, Terrestrial Ecosystems, [SDV]Life Sciences [q-bio], Precipitation, Biomes, Degradation, Soil, Té Rooibos, FOLIAR LITTER, TEMPERATURE, [SDV.EE]Life Sciences [q-bio]/Ecology, environment, Ecology, Nitrógeno, Temperature, Litter decomposition, 04 agricultural and veterinary sciences, Temperatura, Ciclo de Nutrientes, 1181 Ecology, evolutionary biology, Life Sciences & Biomedicine, Nutrient cycle, Climate Change, Environmental Sciences & Ecology, Environmental Science (miscellaneous), Degradación, Liter Descomposition, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Temperate climate, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, 0105 earth and related environmental sciences, Microbial Flora, AVAILABILITY, Chemical process of decomposition, Bolsa de Té, Nutrients, Descomposición de Hojas, SD1-669.5, Decomposition, N DEPOSITION, Environmental sciences, Tea bag, 13. Climate action, Earth and Environmental Sciences, 040103 agronomy & agriculture, PATTERNS, Environmental science, cavelab, Nitrogen deposition, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: Este artículo contiene 18 páginas, 5 tablas, 4 figuras., Litter decomposition is a key process for carbon and nutrient cycling in terrestrial ecosystems and is mainly controlled by environmental conditions, substrate quantity and quality as well as microbial community abundance and composition. In particular, the effects of climate and atmospheric nitrogen (N) deposition on litter decomposition and its temporal dynamics are of significant importance, since their effects might change over the course of the decomposition process. Within the TeaComposition initiative, we incubated Green and Rooibos teas at 524 sites across nine biomes. We assessed how macroclimate and atmospheric inorganic N deposition under current and predicted scenarios (RCP 2.6, RCP 8.5) might affect litter mass loss measured after 3 and 12 months. Our study shows that the early to mid-term mass loss at the global scale was affected predominantly by litter quality (explaining 73% and 62% of the total variance after 3 and 12 months, respectively) followed by climate and N deposition. The effects of climate were not litter-specific and became increasingly significant as decomposition progressed, with MAP explaining 2% and MAT 4% of the variation after 12 months of incubation. The effect of N deposition was litter-specific, and significant only for 12-month decomposition of Rooibos tea at the global scale. However, in the temperate biome where atmospheric N deposition rates are relatively high, the 12- month mass loss of Green and Rooibos teas decreased significantly with increasing N deposition, explaining 9.5% and 1.1% of the variance, respectively. The expected changes in macroclimate and N deposition at the global scale by the end of this century are estimated to increase the 12-month mass loss of easily decomposable litter by 1.1– 3.5% and of the more stable substrates by 3.8–10.6%, relative to current mass loss.In contrast, expected changes in atmospheric N deposition will decrease the mid-term mass loss of high-quality litter by 1.4–2.2% and that of low-quality litter by 0.9–1.5% in the temperate biome. Our results suggest that projected increases in N deposition may have the capacity to dampen the climate-driven increases in litter decomposition depending on the biome and decomposition stage of substrate., This work was performed within the TeaComposition initiative, carried out by 190 institutions worldwide. We thank for funding support for the workshop and data analysis from the ILTER. We acknowledge support by the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, funded by the German Research Foundation (FZT 118), Scientific Grant Agency VEGA (Grant No. 2/0101/18), as well as by the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program (Grant Agreement No. 677232). Thanks are due to FCT/MCTES for the financial support to CESAM (UIDB/50017/2020 + UIDP/50017/2020) and to the project PORBIOTA (POCI-01-0145-FEDER-022127). AI Sousa was funded by national funds through the FCTFoundation for Science and Technology, I.P., under the project CEECIND/00962/2017. HS and CB acknowledge FCT support to cE3c through UID/BIA/00329/2013, UID/BIA/00329/2019, and UIDB/00329/2020, and the project PORBIOTA - POCI-01- 0145-FEDER-022127. We are also thankful to UNILEVER for sponsoring the Lipton tea.
Published: 2021
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4. Abrupt thaw enhances annual global warming potential of an actively degrading permafrost peatland

Author: Sigrid Trier Kjær, Sebastian Westermann, Casper T. Christiansen, Anders Michelsen, Peter Dörsch, Inge H. J. Althuizen, Hanna Lee, and David Risk
Subjects: Peat, Environmental science, Physical geography, Permafrost, Global-warming potential
Abstract: Global scale warming has led to permafrost thaw, which may release large amounts of carbon to the atmosphere as CO2 and CH4, potentially accelerating global warming (i.e. a positive feedback). However, uncertainty in the mechanisms controlling carbon mineralization is compounded by concurrent changes in soil hydrology associated with permafrost thaw. Thawing permafrost can lead to surface water accumulation in some areas and seasonal or permanent soil drying in areas where permafrost thaw opens up new channels of water to penetrate into the groundwater system. The complexity of the hydrologic response to permafrost thaw increases the challenge in generating reliable estimates of the permafrost carbon climate feedback. Furthermore, limited observational data exist to i) quantify the effects of permafrost thaw on net tundra carbon budgets, particularly on an annual basis, and ii) as well as constrain the underlying processes governing carbon release under aerobic and anaerobic conditions.Here, we investigated how changes in local hydrology affects CO2 and CH4 release from permafrost soils by establishing a field gradient study in northern Norway (69ᵒ N), where recent abrupt degradation of permafrost created thaw ponds in palsa-mire ecosystems. The site exhibits a natural gradient of permafrost thaw, which also corresponds to a strong hydrological gradient (i.e. dry palsas with intact permafrost, seasonally inundated thaw slumps, and thaw ponds). Since 2017, we have used a range of manual and automated techniques to measure changes in vegetation, soil and water microclimate, biogeochemistry, and soil CO2 and CH4 concentrations and efflux across the permafrost thaw gradient.Our preliminary results show that abrupt permafrost thaw and landscape subsidence – both intermediate slumping and thaw pond formation – increase net annual carbon loss from this type of subarctic wetland. Permafrost thaw approximately doubles CO2 emissions from thaw slumps compared to vegetated or soil palsas. Furthermore, CH4 release greatly increased across the permafrost thaw gradient. While vegetated palsas were small sinks of atmospheric CH4 during the growing season, permafrost thaw slumping and pond formation led to a dramatic increase in CH4 efflux compared to bare palsas. In contrast, bare soil palsas on were the most important source of N2O. Soil profile CO2 and CH4 concentrations in thawed permafrost plots were overall highly enriched relative to palsa profiles, reflecting soil conditions with inundated pore space and low oxygen availability along the permafrost thaw gradient. We therefore conclude that abrupt thaw will increase annual carbon loss in subarctic palsa wetlands.
Published: 2021
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5. Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems

Author: Toke T. Høye, Benjamin M. Jones, Marguerite Mauritz, Kirsty Langley, Lydia J. S. Vaughn, Gesche Blume-Werry, Thomas A. Douglas, James A. Laundre, Gareth K. Phoenix, Anders Michelsen, Elyn Humphreys, Michael M. Loranty, Susan M. Natali, M. Torre Jorgenson, Alexander Kholodov, Sean M. P. Cahoon, Julia Boike, Gerald V. Frost, Laura Gough, Hiroki Iwata, Mathew Williams, E. Blanc-Betes, Eugénie S. Euskirchen, Benjamin W Abbot, Heather Kropp, Ken D. Tape, Jan Hjort, Jonathan A. O'Donnell, Jakob Abermann, Daan Blok, Masahito Ueyama, Oliver Sonnentag, Monique M. P. D. Heijmans, Bo Elberling, Inge Grünberg, Casper T. Christiansen, M. Goeckede, Amy L. Breen, Magnus Lund, V. G. Salmon, Bang-Yong Lee, Isla H. Myers-Smith, Howard E. Epstein, Adrian V. Rocha, A. Britta K. Sannel, Sharon L. Smith, Peter M. Lafleur, Yongwon Kim, Gabriela Schaepman-Strub, Steven D. Mamet, and David Olefeldt
Subjects: DYNAMICS, 010504 meteorology & atmospheric sciences, ACTIVE-LAYER, soil temperature, ved/biology.organism_classification_rank.species, Plant Ecology and Nature Conservation, HEAT, 010501 environmental sciences, Permafrost, Atmospheric sciences, 01 natural sciences, Shrub, NORTHERN ALASKA, Arctic, vegetation change, TEMPERATURES, boreal forest, Thaw depth, 0105 earth and related environmental sciences, General Environmental Science, CLIMATE-CHANGE, WIMEK, Renewable Energy, Sustainability and the Environment, ved/biology, Taiga, Public Health, Environmental and Occupational Health, Soil carbon, Vegetation, PERMAFROST THAW, EXPANSION, 15. Life on land, Tundra, 13. Climate action, SNOW, Environmental science, Plantenecologie en Natuurbeheer, VEGETATION, permafrost
Abstract: Soils are warming as air temperatures rise across the Arctic and Boreal region concurrent with the expansion of tall-statured shrubs and trees in the tundra. Changes in vegetation structure and function are expected to alter soil thermal regimes, thereby modifying climate feedbacks related to permafrost thaw and carbon cycling. However, current understanding of vegetation impacts on soil temperature is limited to local or regional scales and lacks the generality necessary to predict soil warming and permafrost stability on a pan-Arctic scale. Here we synthesize shallow soil and air temperature observations with broad spatial and temporal coverage collected across 106 sites representing nine different vegetation types in the permafrost region. We showed ecosystems with tall-statured shrubs and trees (>40 cm) have warmer shallow soils than those with short-statured tundra vegetation when normalized to a constant air temperature. In tree and tall shrub vegetation types, cooler temperatures in the warm season do not lead to cooler mean annual soil temperature indicating that ground thermal regimes in the cold-season rather than the warm-season are most critical for predicting soil warming in ecosystems underlain by permafrost. Our results suggest that the expansion of tall shrubs and trees into tundra regions can amplify shallow soil warming, and could increase the potential for increased seasonal thaw depth and increase soil carbon cycling rates and lead to increased carbon dioxide loss and further permafrost thaw.
Published: 2021
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6. Decomposition of Senesced Leaf Litter is Faster in Tall Compared to Low Birch Shrub Tundra

Author: Casper T. Christiansen, Michelle C. Mack, Jennie DeMarco, and Paul Grogan
Subjects: 010504 meteorology & atmospheric sciences, Ecology, biology, ved/biology, ved/biology.organism_classification_rank.species, 04 agricultural and veterinary sciences, Plant litter, Snow, biology.organism_classification, 01 natural sciences, Shrub, Groundcover, Tundra, Decomposer, Deciduous, Agronomy, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental Chemistry, Environmental science, Betula neoalaskana, human activities, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences
Abstract: Many Low Arctic tundra regions are currently undergoing a vegetation shift towards increasing growth and groundcover of tall deciduous shrubs due to recent climate warming. Vegetation change directly affects ecosystem carbon balance, but it can also affect soil biogeochemical cycling through physical and biological feedback mechanisms. Recent studies indicate that enhanced snow accumulation around relatively tall shrubs has negligible physical effect on litter decomposition rates. However, these investigations were no more than 3 years, and therefore may be insufficient to detect differences in inherently slow biogeochemical processes. Here, we report a 5-year study near Daring Lake, Canada, comparing Betula neoalaskana foliar litter decay rates within unmanipulated and snowfenced low-stature birch (height: ~ 0.3 m) plots to test the physical effect of experimentally deepened snow, and within tall birch (height: ~ 0.8 m) plots to test the combined physical and biological effects, that is, deepened snow plus strong birch dominance. Having corrected for carbon gain by the colonizing decomposers, actual litter carbon loss increased by approximately 25% in the tall birch relative to both low birch sites. Decay of lignin-like acid unhydrolizable litter residues also accelerated in the tall birch site, and a similar but lower magnitude response in the snowfenced low birch site indicated that physical effects of deepened snow were at least partially responsible. In contrast, deepened snow alone did not affect litter carbon loss. Our findings suggest that a combination of greater litter inputs, altered soil microbial community, enhanced soil nutrient pools, and warmer winter soils together promote relatively fast decomposition of recalcitrant litter carbon in tall birch shrub environments.
Published: 2018
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7. Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO2gain but reduces soil carbon and nutrient pools

Author: Paul Grogan, Gregory H. R. Henry, Casper T. Christiansen, and Melissa J. Lafrenière
Subjects: Global and Planetary Change, 010504 meteorology & atmospheric sciences, Ecology, ved/biology, Soil organic matter, ved/biology.organism_classification_rank.species, 04 agricultural and veterinary sciences, Soil carbon, 15. Life on land, Evergreen, Snow, 01 natural sciences, Shrub, Tundra, Agronomy, 13. Climate action, 040103 agronomy & agriculture, 0401 agriculture, forestry, and fisheries, Environmental Chemistry, Environmental science, Ecosystem respiration, Thaw depth, 0105 earth and related environmental sciences, General Environmental Science
Abstract: Arctic climate warming will be primarily during winter, resulting in increased snowfall in many regions. Previous tundra research on the impacts of deepened snow has generally been of short duration. Here, we report relatively long-term (7-9 years) effects of experimentally deepened snow on plant community structure, net ecosystem CO2 exchange (NEE), and soil biogeochemistry in Canadian Low Arctic mesic shrub tundra. The snowfence treatment enhanced snow depth from 0.3 to ~1 m, increasing winter soil temperatures by ~3°C, but with no effect on summer soil temperature, moisture, or thaw depth. Nevertheless, shoot biomass of the evergreen shrub Rhododendron subarcticum was near-doubled by the snowfences, leading to a 52% increase in aboveground vascular plant biomass. Additionally, summertime NEE rates, measured in collars containing similar plant biomass across treatments, were consistently reduced ~30% in the snowfenced plots due to decreased ecosystem respiration rather than increased gross photosynthesis. Phosphate in the organic soil layer (0-10 cm depth) and nitrate in the mineral soil layer (15-25 cm depth) were substantially reduced within the snowfences (47-70 and 43%-73% reductions, respectively, across sampling times). Finally, the snowfences tended (p = .08) to reduce mineral soil layer C% by 40%, but with considerable within- and among plot variation due to cryoturbation across the landscape. These results indicate that enhanced snow accumulation is likely to further increase dominance of R. subarcticum in its favored locations, and reduce summertime respiration and soil biogeochemical pools. Since evergreens are relatively slow growing and of low stature, their increased dominance may constrain vegetation-related feedbacks to climate change. We found no evidence that deepened snow promoted deciduous shrub growth in mesic tundra, and conclude that the relatively strong R. subarcticum response to snow accumulation may explain the extensive spatial variability in observed circumpolar patterns of evergreen and deciduous shrub growth over the past 30 years.
Published: 2018
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8. Examination of Soil Microbial Communities After Permafrost Thaw Subsequent to an Active Layer Detachment in the High Arctic

Author: Kristy Moniz, Casper T. Christiansen, Virginia K. Walker, Scott N. Montross, Daniel Lamhonwah, Cara N. Inglese, Scott F. Lamoureux, Paul Grogan, and Melissa J. Lafrenière
Subjects: 0301 basic medicine, Global and Planetary Change, Ecology, Permafrost, Active layer, 03 medical and health sciences, 030104 developmental biology, Microbial population biology, Arctic, Environmental chemistry, Dissolved organic carbon, Soil water, Environmental science, Ecosystem, Ecology, Evolution, Behavior and Systematics, Temperature gradient gel electrophoresis, Earth-Surface Processes
Abstract: Active layer detachments (ALDs) are permafrost disturbances associated with climate change and increased seasonal warming. Such perturbations result from thawing of the upper permafrost and downslope movement of the overlying thawed material, including the active layer. ALDs have the potential to impact soil microbial community composition and function in arctic soil ecosystems. Here we report an initial investigation of an ALD located at Cape Bounty on Melville Island in the Canadian High Arctic. We examined soil nutrient content as well as microbial community structure using denaturing gradient gel electrophoresis and sequencing. Soil from the disturbed site showed changes in microbial communities with strikingly different fungal community composition compared to soils from an adjacent undisturbed site. These community changes were correlated with enhanced levels of dissolved organic carbon, microbial carbon, total dissolved nitrogen, and microbial nitrogen. The Nitrososphaerales—an order of am...
Published: 2017
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9. Large loss of CO2 in winter observed across the northern permafrost region

Author: Gerardo Celis, Jack W. McFarland, David Olefeldt, Mathias Göckede, Jennifer D. Watts, Christian Wille, Torben R. Christensen, Gregory Starr, Casper T. Christiansen, S. Potter, Kevin Schaefer, Jordan P. Goodrich, N. Pirk, Benjamin W. Abbott, Patrick M. Crill, Elisabeth J. Cooper, Edward A. G. Schuur, Qianlai Zhuang, Zhihua Liu, Bang Yong Lee, Massimo Lupascu, Xiaofeng Xu, Kyle A. Arndt, Torsten Sachs, Walter C. Oechel, Donatella Zona, S. Ludwig, Jinyang Du, Brendan M. Rogers, Michael M. Loranty, Mark J. Lara, Yongwon Kim, Oliver Sonnentag, Zhen Zhang, Susan M. Natali, David Risk, Gaius R. Shaver, Aram Kalhori, A. David McGuire, Bo Elberling, Mats P. Björkman, Leah Birch, Roser Matamala, Philipp R. Semenchuk, Klaus Steenberg Larsen, Manuel Helbig, M. P. Waldrop, Frans-Jan W. Parmentier, Thomas Friborg, Yihui Wang, Julie D. Jastrow, Anders Michelsen, Hélène Genet, Roisin Commane, Fereidoun Rezanezhad, Claudia I. Czimczik, Elchin Jafarov, Lars Kutzbach, A. Anthony Bloom, Christina Minions, Jeffrey M. Welker, Claire C. Treat, Eugénie S. Euskirchen, Patrick F. Sullivan, Nima Madani, Magnus Lund, Jocelyn Egan, William L. Quinton, Paul Grogan, Niels Martin Schmidt, Avni Malhotra, Ben Poulter, S. P. Davydov, A. K. Selbmann, and John S. Kimball
Subjects: 010504 meteorology & atmospheric sciences, Environmental Science and Management, Growing season, Environmental Science (miscellaneous), Atmospheric sciences, Permafrost, 01 natural sciences, Physical Geography and Environmental Geoscience, Atmospheric Sciences, 03 medical and health sciences, chemistry.chemical_compound, VDP::Mathematics and natural science: 400::Zoology and botany: 480, Ecosystem, 030304 developmental biology, 0105 earth and related environmental sciences, 0303 health sciences, Soil organic matter, 15. Life on land, Climate Action, chemistry, Arctic, Boreal, 13. Climate action, Carbon dioxide, Soil water, Environmental science, Social Sciences (miscellaneous), VDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480
Abstract: Recent warming in the Arctic, which has been amplified during the winter1–3, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)4. However, the amount of CO2 released in winter is not known and has not been well represented by ecosystem models or empirically based estimates5,6. Here we synthesize regional in situ observations of CO2 flux from Arctic and boreal soils to assess current and future winter carbon losses from the northern permafrost domain. We estimate a contemporary loss of 1,662 TgC per year from the permafrost region during the winter season (October–April). This loss is greater than the average growing season carbon uptake for this region estimated from process models (−1,032 TgC per year). Extending model predictions to warmer conditions up to 2100 indicates that winter CO2 emissions will increase 17% under a moderate mitigation scenario—Representative Concentration Pathway 4.5—and 41% under business-as-usual emissions scenario—Representative Concentration Pathway 8.5. Our results provide a baseline for winter CO2 emissions from northern terrestrial regions and indicate that enhanced soil CO2 loss due to winter warming may offset growing season carbon uptake under future climatic conditions. Winter warming in the Arctic will increase the CO2 flux from soils. A pan-Arctic analysis shows a current loss of 1,662 TgC per year over the winter, exceeding estimated carbon uptake in the growing season; projections suggest a 17% increase under RCP 4.5 and a 41% increase under RCP 8.5 by 2100.
Published: 2019
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10. Long-term experimentally deepened snow decreases growing-season respiration in a low- and high-arctic tundra ecosystem

Author: Paul Grogan, Philipp R. Semenchuk, Bo Elberling, Elisabeth J. Cooper, and Casper T. Christiansen
Subjects: 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Ecology, Global warming, Paleontology, Soil Science, Growing season, Forestry, 15. Life on land, Aquatic Science, Snow, Atmospheric sciences, 010603 evolutionary biology, 01 natural sciences, Tundra, 13. Climate action, Climatology, Soil water, Environmental science, Ecosystem, Ecosystem respiration, 0105 earth and related environmental sciences, Water Science and Technology, Snow fence
Abstract: Tundra soils store large amounts of carbon (C) that could be released through enhanced ecosystem respiration (ER) as the arctic warms. Over time, this may change the quantity and quality of available soil C pools, which in-turn may feedback and regulate ER responses to climate warming. Therefore, short-term increases in ER rates due to experimental warming may not be sustained over longer periods, as observed in other studies. One important aspect, which is often overlooked, is how climatic changes affecting ER in one season may carry-over and determine ER in following seasons. Using snow fences, we increased snow depth and thereby winter soil temperatures in a high-arctic site in Svalbard (78°N) and a low-arctic site in the Northwest Territories, Canada (64°N), for 5 and 9 years, respectively. Deepened snow enhanced winter ER while having negligible effect on growing-season soil temperatures and soil moisture. Growing-season ER at the high-arctic site was not affected by the snow treatment after 2 years. However, surprisingly, the deepened snow treatments significantly reduced growing-season ER rates after 5 years at the high-arctic site and after 8–9 years at the low-arctic site. We speculate that the reduction in ER rates, that became apparent only after several years of experimental manipulation, may, at least in part, be due to prolonged depletion of labile C substrate as a result of warmer soils over multiple cold seasons. Long-term changes in winter climate may therefore significantly influence annual net C balance not just because of increased wintertime C loss but also because of “legacy” effects on ER rates during the following growing seasons.
Published: 2016
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11. Early stage litter decomposition across biomes

Author: Umberto Morra di Cella, Sean P. Charles, Matteo Gualmini, Naoko Tokuchi, Michael Mirtl, Marta Lobão Lopes, Takeshi Ise, Inmaculada García Quirós, Geovana Carreño-Rocabado, Arne Verstraeten, Joan-Albert Sanchez-Cabeza, Thomas Zechmeister, Jill Thompson, Norbert Hölzel, Maroof Hamid, Rodrigo Lemes Martins, Taiki Mori, José Marcelo Domingues Torezan, Dana Polyanskaya, Peter Haase, Björn Berg, Angela Stanisci, Issaka Senou, Inger Kappel Schmidt, Markus Wagner, Adriano Caliman, Laurel M. Brigham, Alejandro Valdecantos, Céline Meredieu, Kalifa Coulibaly, Margarida Santos-Reis, Georg Wohlfahrt, Regin Rønn, Marcello Tomaselli, Martin Weih, Bernd Ahrends, Kaie Kriiska, Anja Schmidt, Luciana S. Carneiro, Ana I. Lillebø, Alessandro Petraglia, Algirdas Augustaitis, Ana I. Sousa, Sonja Wipf, Chi-Ling Chen, Hassan Bismarck Nacro, Sue J. Milton, Ivan Mihal, Ika Djukic, Florence Maunoury-Danger, Peter Fleischer, Tatsuro Nakaji, Cendrine Mony, Sara Puijalon, Rafael D. Guariento, Rosa Isela Meneses, Mihai Pușcaș, Pablo Luis Peri, Flurin Sutter, Kate Lajtha, Peter B. Reich, Lindsey E. Rustad, María Guadalupe Almazán Torres, Laura Williams, George L. Vourlitis, Evanilde Benedito, Arely N. Palabral-Aguilera, Luis Villar, Stefanie Hoeber, Juan J. Jiménez, Esperança Gacia, Alba Gutiérrez-Girón, Kazuhiko Hoshizaki, Takanori Sato, Eric Lucot, Osvaldo Borges Pinto, Artur Stefanski, Andrew R. Smith, Takuo Hishi, Rosario G. Gavilán, Till Kleinebecker, Julia Seeber, Gina Arena, Marcelo Sternberg, Mo Jiangming, Tsutom Hiura, Satoshi N. Suzuki, Jeyanny Vijayanathan, Christine Delire, Francisco Cuesta, Bill Parker, Mark Frenzel, Franz Zehetner, Vincent Maire, Edward Crawford, Heinke Jäger, Nicolas Lecomte, Tanaka Kenta, Yuji Kominami, Joseph C. Morina, Paige E. Weber, Pavel Dan Turtureanu, Marc Lebouvier, Pascal Vittoz, Jónína Sigríður Þorláksdóttir, Anne Probst, David Fuentes Delgado, Laura Yahdjian, Johan Neirynck, Isaac Ahanamungu Makelele, Bernard Bosman, Fábio Padilha Bolzan, Yury Rozhkov, Ute Hamer, Henning Meesenburg, Vinicius F. Farjalla, Steffen Seitz, Marie-Noëlle Pons, Jess K. Zimmerman, Hans Verbeeck, Thomas Scholten, Elena Preda, Thomas Spiegelberger, Romain Georges, Stefan Löfgren, Ferdinand Kristöfel, Pierre Marmonier, Juha M. Alatalo, Katalin Szlavecz, Ana Carolina Ruiz Fernández, Johannes M. H. Knops, Rita Adrian, Vanessa Mendes Rêgo, Jean-Christophe Lata, Rafaella Canessa, Kathrin Käppeler, Andrea Fischer, Michael Bierbaumer, Jiří Doležal, Hideaki Shibata, Marcus Schaub, Zsolt Toth, Diyaa Radeideh, Matthew A. Vadeboncoeur, Robert Kanka, William H. McDowell, Birgit Sattler, Jean-Luc Probst, Mioko Ataka, Katarína Gerhátová, Jawad Shoqeir, Stefan Stoll, Michael Danger, Sébastien Gogo, Katja Tielbörger, Laryssa Helena Ribeiro Pazianoto, Bo Yang, Franco L. Souza, John Loehr, Francisco de Almeida Lobo, Michael J. Liddell, Sylvie Dousset, Dirk Wundram, Ralf Kiese, Yalin Hu, Miglena Zhiyanski, José-Luis Benito-Alonso, Katie A. Jennings, Tsutomu Enoki, Helena Cristina Serrano, Quentin Ponette, Helge Bruelheide, Simon Drollinger, Vincent Bretagnolle, Ivika Ostonen, Lambiénou Yé, Javier Roales, Philippe Choler, Madison Morley, Charles A. Nock, Grizelle González, Tudor-Mihai Ursu, Maaike Y. Bader, Cristina Branquinho, Hugo López Rosas, Nina V. Filippova, Erzsébet Hornung, Anzar A. Khuroo, Lourdes Morillas, Harald Auge, Andreas Bohner, Florian Kitz, Stephan Glatzel, Aurora Gaxiola, Marijn Bauters, Stefan Trogisch, Guylaine Canut, Oscar Romero, Hélène Verheyden, Yulia Zaika, Veronika Piscová, Michael Scherer-Lorenzen, Valentin H. Klaus, Elena Tropina, Michele Di Musciano, Marie-Andrée Giroux, Florian Hofhansl, Wenjun Zhou, Corinna Rebmann, Thomas J. Mozdzer, Zsolt Kotroczó, Evy Ampoorter, Michal Růžek, Jana Borovská, Jianwu Tang, Petr Petřík, Juan Dario Quinde, Simone Mereu, Esther Lévesque, Olga Ferlian, Veronika Fontana, Joël Merlet, Stacey M. Trevathan-Tackett, André-Jean Francez, Wentao Luo, Héctor Alejandro Bahamonde, Roberto Cazzolla Gatti, Brigitta Erschbamer, Christopher Andrews, Marie-Anne de Graaff, Martin Schädler, Luciano Di Martino, Verena Busch, Elli Groner, Victoria Carbonell, Michinari Matsushita, Maria Glushkova, Sarah Freda, Alain Paquette, Annie Ouin, Robert Weigel, Monique Carnol, Bohdan Juráni, Ian D. Yesilonis, Jean-Paul Theurillat, Hugo L. Rojas Villalobos, Alberto Humber, Martha Apple, Nico Eisenhauer, Claus Beier, Hermann F. Jungkunst, Hiroko Kurokawa, Nadia Barsoum, Thierry Camboulive, Klaus Steenberg Larsen, Frank Berninger, Laura Dienstbach, Yasuhiro Utsumi, Inara Melece, Felipe Varela, Sally Wittlinger, Christian Rixen, Valter Di Cecco, Anderson da Rocha Gripp, Marina Mazón, E. Carol Adair, Hanna Lee, István Fekete, Liesbeth van den Brink, José-Gilberto Cardoso-Mohedano, Ken Green, Heike Feldhaar, Jonathan von Oppen, Michele Carbognani, Lu Xiankai, Christophe Piscart, Fernando T. Maestre, Karibu Fukuzawa, Chiao-Ping Wang, Bart Muys, Lipeng Zhang, Harald Pauli, Inge van Halder, Carmen Eugenia Rodríguez Ortíz, Eduardo Ordóñez-Regil, Priscilla Muriel, Heather D. Alexander, Sebastian Kepfer-Rojas, Victoria Ochoa, Casper T. Christiansen, Mohammed Alsafran, Thaisa Sala Michelan, Christel Baum, Amélie Saillard, Hervé Jactel, Markus Didion, Evgeny A. Davydov, Sabyasachi Dasgupta, Anna Avila, Andrijana Andrić, Kris Verheyen, Jörg Löffler, Gisele Daiane Pinha, Anikó Seres, Jutta Stadler, Milan Barna, Andrey V. Malyshev, Rebecca E. Hewitt, Joh R. Henschel, Peter I. Macreadie, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Norwegian Institute for Water Research (NIVA), Swedish University of Agricultural Sciences (SLU), Dept Forest & Water Management, Lab Forestry, Universiteit Gent = Ghent University [Belgium] (UGENT), Centre for Forest Research (CFR), Université du Québec à Montréal = University of Québec in Montréal (UQAM), Laboratoire d'Ecologie Alpine (LECA ), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria = National Institute for Agricultural and Food Research and Technology (INIA), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institute for Climate and Atmospheric Science [Leeds] (ICAS), School of Earth and Environment [Leeds] (SEE), University of Leeds-University of Leeds, Laboratoire Ecologie Fonctionnelle et Environnement (ECOLAB), Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Dynamiques Forestières dans l'Espace Rural (DYNAFOR), Institut National de la Recherche Agronomique (INRA)-École nationale supérieure agronomique de Toulouse [ENSAT]-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, European Forest Institute = Institut Européen de la Forêt = Euroopan metsäinstituutti (EFI), Institute of Information Engineering [Beijing] (IIE), Chinese Academy of Sciences [Beijing] (CAS), Biodiversité, Gènes & Communautés (BioGeCo), Institut National de la Recherche Agronomique (INRA)-Université de Bordeaux (UB), University of Rostock, WSL Institute for Snow and Avalanche Research SLF, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Department Computational Hydrosystems [UFZ Leipzig], Helmholtz Zentrum für Umweltforschung = Helmholtz Centre for Environmental Research (UFZ), Laboratoire Chrono-environnement - CNRS - UBFC (UMR 6249) (LCE), Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Département de chimie-biologie & Centre d’études nordiques [CANADA], Université du Québec à Trois-Rivières (UQTR), Area de Biodiversidad y Conservaciín, Universidad Rey Juan Carlos [Madrid] (URJC), Laboratoire Interdisciplinaire des Environnements Continentaux (LIEC), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Terre et Environnement de Lorraine (OTELo), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Institute of Soil Research, Universität für Bodenkultur Wien = University of Natural Resources and Life [Vienne, Autriche] (BOKU), Institute of Ecology, University of Innsbruck, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Computational & Applied Vegetation Ecology (CAVElab), Department Community Ecology [UFZ Leipzig], University of Vienna [Vienna], Institut du Développement rural (IDR), Université Polytechnique Nazi Boni Bobo-Dioulasso (UNB), Unité de recherche Comportement et Ecologie de la Faune Sauvage (CEFS), Institut National de la Recherche Agronomique (INRA), Institute of Biology/Geobotany and Botanical Garden, Martin-Luther-Universität Halle Wittenberg (MLU), Tohoku University [Sendai], Institute of Ecology and Earth Sciences [Tartu], University of Tartu, Institut d'écologie et des sciences de l'environnement de Paris (iEES), Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre alpien de Phytogéographie (CAP), Fondation Jean-Marcel Aubert, Inst Trop Ecosyst Studies, University of Puerto Rico (UPR), Universidad de Valladolid [Valladolid] (UVa), Mountain Agriculture Research Unit, Centre international de recherche-développement sur l'élevage en zone sub-humide (CIRDES), Centre Universitaire Polytechnique de Dédougou (CUP-D), Université Joseph Ki-Zerbo [Ouagadougou] (UJZK), USDA Forest Service, Instituto Pirenaico de Ecologia = Pyrenean Institute of Ecology (IPE), Station Biologique de Paimpont CNRS UMR 6653 (OSUR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Institute of Pharmacology and Toxicology [Zurich], Universität Zürich [Zürich] = University of Zurich (UZH), Centre for Ecology - Evolution and Environmental Changes (cE3c) - Faculdade de Ciências, Universidade de Lisboa = University of Lisbon (ULISBOA), Canada Research in Northern Biodiversity, Université du Québec à Rimouski (UQAR), Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Zone Atelier du Bassin de la Moselle [LTSER France] (ZAM), Department of Crop Production Ecology, University of Freiburg, Forest Research Institute- BAS, Bulgarian Academy of Sciences (BAS), Lab Plant & Microbial Ecol, Inst Bot B22, Université de Liège, Laboratoire Dynamique de la Biodiversité (LADYBIO), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Leipzig University, Westfälische Wilhelms-Universität Münster = University of Münster (WWU), Universitat Politècnica de Catalunya [Barcelona] (UPC), Université de Lausanne = University of Lausanne (UNIL), Department of Limnology and Conservation, Senckenberg Research Institutes and Natural History Museums, Department of Forest Resources, University of Minnesota [Twin Cities] (UMN), University of Minnesota System-University of Minnesota System, Laboratoire d'Ecologie des Hydrosystèmes Naturels et Anthropisés (LEHNA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE)-Centre National de la Recherche Scientifique (CNRS), Université Catholique de Louvain = Catholic University of Louvain (UCL), Institut für Meteorologie und Klimaforschung - Atmosphärische Umweltforschung (IMK-IFU), Karlsruher Institut für Technologie (KIT), Institut des Sciences de la Terre d'Orléans - UMR7327 (ISTO), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Biogéosystèmes Continentaux - UMR7327, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Department of Science for Nature and Natural Resources, Università degli Studi di Sassari = University of Sassari [Sassari] (UNISS), Biogéosciences [UMR 6282] (BGS), Université de Bourgogne (UB)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Tomakomai Research Station, Field Science Center for Northern Biosphere, Hokkaido University [Sapporo, Japan], Bangor University, Technische Universität Dresden = Dresden University of Technology (TU Dresden), Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), LTSER «Zone Atelier Plaine & Val de Sevre» [France], Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Condensed Matter Theory Laboratory RIKEN (RIKEN), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), 730938, Biological Interactions Doctoral Programme, Secretaría de Educación Superior, Ciencia, Tecnología e Innovación, 2/0101/18, Scientific Grant Agency VEGA, 2190, Fundación Charles Darwin, UID/AMB/50017, Centro de Estudos Ambientais e Marinhos, Universidade de Aveiro, ILTER Initiative Grant, ClimMani Short-Term Scientific Missions Grant, ES1308-231015-068365, Austrian Environment Agency, SFRH/BPD/107823/2015, Portuguese Foundation, DEB-1557009, NSF, UID/BIA/00329/2013, Fundação para a Ciência e Tecnologia, Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), University of Helsinki, Universität für Bodenkultur Wien [Vienne, Autriche] (BOKU), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Recherche Agronomique (INRA), Centre alpien de Phytogéographie, Fondation J.-M. Aubert, Centre international de recherche-développement sur l'élevage en zone Subhumide (CIRDES), Centre international de recherche-développement sur l'élevage en zone Subhumide, Instituto Pirenaico de Ecologia (IPE), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), University of Lisbon, Université de Leipzig, Westfälische Wilhelms-Universität Münster (WWU), Université de Lausanne (UNIL), University of Sassari, Biogéosciences [UMR 6282] [Dijon] (BGS), Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Centre National de la Recherche Scientifique (CNRS), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Universiteit Gent = Ghent University (UGENT), Université de Rennes (UR)-Institut Ecologie et Environnement (INEE), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Ecologie Fonctionnelle et Environnement (LEFE), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Institut National de la Recherche Agronomique (INRA)-École nationale supérieure agronomique de Toulouse (ENSAT), Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Laboratoire Chrono-environnement (UMR 6249) (LCE), Leopold Franzens Universität Innsbruck - University of Innsbruck, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Instituto Pirenaico de Ecologìa = Pyrenean Institute of Ecology [Zaragoza] (IPE - CSIC), Université de Rennes (UR), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - INPT (FRANCE), Institut National de la Recherche Agronomique - INRA (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Météo France (FRANCE), UCL - SST/ELI/ELIE - Environmental Sciences, Swiss Federal Institute for Forest, Snow and Avalanche Research WSL, Swedish University of Agricultural Sciences - Department of Forest Soils, Ghent University [Belgium] (UGENT), Université du Québec à Montréal (UQAM), Laboratoire d'Ecologie Alpine (LECA), Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA), Spanish National Institute for Agriculture and Food Research and Technology (INIA), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Science Politique Relations Internationales Territoire (SPIRIT), Université Montesquieu - Bordeaux 4-Institut d'Études Politiques [IEP] - Bordeaux-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure Agronomique de Toulouse-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Bordeaux (UB)-Institut National de la Recherche Agronomique (INRA), University of Rostock [Germany], Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Helmholtz Centre for Environmental Research (UFZ), Universiteit Gent [Ghent], Laboratoire de Comportement et d'Ecologie de la Faune Sauvage, INRA, 31326 Castanet-Tolosan cedex, France, Institut d'écologie et des sciences de l'environnement de Paris (IEES), Universidad de Puerto Rico, Centre Universitaire Polytechnique de Dédougou, Université de Ouagadougou, Instituto Pirenaico de Ecología, IPE-CSIC, University of Zürich [Zürich] (UZH), LTSER Zone Atelier du Bassin de la Moselle, Helmholtz Zentrum für Umweltforschung (UFZ), Institute of Terrestrial Ecosystems, University of Minnesota [Twin Cities], Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Nationale des Travaux Publics de l'État (ENTPE), Université Catholique de Louvain (UCL), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Bureau de Recherches Géologiques et Minières (BRGM) (BRGM)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Centre National de la Recherche Scientifique (CNRS)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Hokkaido University, Technische Universität Dresden (TUD), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA)-Université de La Rochelle (ULR), LTSER Zone Atelier Plaine & Val de Sèvre, Djukic I., Kepfer-Rojas S., Schmidt I.K., Larsen K.S., Beier C., Berg B., Verheyen K., Caliman A., Paquette A., Gutierrez-Giron A., Humber A., Valdecantos A., Petraglia A., Alexander H., Augustaitis A., Saillard A., Fernandez A.C.R., Sousa A.I., Lillebo A.I., da Rocha Gripp A., Francez A.-J., Fischer A., Bohner A., Malyshev A., Andric A., Smith A., Stanisci A., Seres A., Schmidt A., Avila A., Probst A., Ouin A., Khuroo A.A., Verstraeten A., Palabral-Aguilera A.N., Stefanski A., Gaxiola A., Muys B., Bosman B., Ahrends B., Parker B., Sattler B., Yang B., Jurani B., Erschbamer B., Ortiz C.E.R., Christiansen C.T., Carol Adair E., Meredieu C., Mony C., Nock C.A., Chen C.-L., Wang C.-P., Baum C., Rixen C., Delire C., Piscart C., Andrews C., Rebmann C., Branquinho C., Polyanskaya D., Delgado D.F., Wundram D., Radeideh D., Ordonez-Regil E., Crawford E., Preda E., Tropina E., Groner E., Lucot E., Hornung E., Gacia E., Levesque E., Benedito E., Davydov E.A., Ampoorter E., Bolzan F.P., Varela F., Kristofel F., Maestre F.T., Maunoury-Danger F., Hofhansl F., Kitz F., Sutter F., Cuesta F., de Almeida Lobo F., de Souza F.L., Berninger F., Zehetner F., Wohlfahrt G., Vourlitis G., Carreno-Rocabado G., Arena G., Pinha G.D., Gonzalez G., Canut G., Lee H., Verbeeck H., Auge H., Pauli H., Nacro H.B., Bahamonde H.A., Feldhaar H., Jager H., Serrano H.C., Verheyden H., Bruelheide H., Meesenburg H., Jungkunst H., Jactel H., Shibata H., Kurokawa H., Rosas H.L., Rojas Villalobos H.L., Yesilonis I., Melece I., Van Halder I., Quiros I.G., Makelele I., Senou I., Fekete I., Mihal I., Ostonen I., Borovska J., Roales J., Shoqeir J., Lata J.-C., Theurillat J.-P., Probst J.-L., Zimmerman J., Vijayanathan J., Tang J., Thompson J., Dolezal J., Sanchez-Cabeza J.-A., Merlet J., Henschel J., Neirynck J., Knops J., Loehr J., von Oppen J., Thorlaksdottir J.S., Loffler J., Cardoso-Mohedano J.-G., Benito-Alonso J.-L., Torezan J.M., Morina J.C., Jimenez J.J., Quinde J.D., Alatalo J., Seeber J., Stadler J., Kriiska K., Coulibaly K., Fukuzawa K., Szlavecz K., Gerhatova K., Lajtha K., Kappeler K., Jennings K.A., Tielborger K., Hoshizaki K., Green K., Ye L., Pazianoto L.H.R., Dienstbach L., Williams L., Yahdjian L., Brigham L.M., van den Brink L., Rustad L., Zhang L., Morillas L., Xiankai L., Carneiro L.S., Di Martino L., Villar L., Bader M.Y., Morley M., Lebouvier M., Tomaselli M., Sternberg M., Schaub M., Santos-Reis M., Glushkova M., Torres M.G.A., Giroux M.-A., de Graaff M.-A., Pons M.-N., Bauters M., Mazon M., Frenzel M., Didion M., Wagner M., Hamid M., Lopes M.L., Apple M., Schadler M., Weih M., Gualmini M., Vadeboncoeur M.A., Bierbaumer M., Danger M., Liddell M., Mirtl M., Scherer-Lorenzen M., Ruzek M., Carbognani M., Di Musciano M., Matsushita M., Zhiyanski M., Puscas M., Barna M., Ataka M., Jiangming M., Alsafran M., Carnol M., Barsoum N., Tokuchi N., Eisenhauer N., Lecomte N., Filippova N., Holzel N., Ferlian O., Romero O., Pinto O.B., Peri P., Weber P., Vittoz P., Turtureanu P.D., Fleischer P., Macreadie P., Haase P., Reich P., Petrik P., Choler P., Marmonier P., Muriel P., Ponette Q., Guariento R.D., Canessa R., Kiese R., Hewitt R., Ronn R., Adrian R., Kanka R., Weigel R., Gatti R.C., Martins R.L., Georges R., Meneses R.I., Gavilan R.G., Dasgupta S., Wittlinger S., Puijalon S., Freda S., Suzuki S., Charles S., Gogo S., Drollinger S., Mereu S., Wipf S., Trevathan-Tackett S., Lofgren S., Stoll S., Trogisch S., Hoeber S., Seitz S., Glatzel S., Milton S.J., Dousset S., Mori T., Sato T., Ise T., Hishi T., Kenta T., Nakaji T., Michelan T.S., Camboulive T., Mozdzer T.J., Scholten T., Spiegelberger T., Zechmeister T., Kleinebecker T., Hiura T., Enoki T., Ursu T.-M., di Cella U.M., Hamer U., Klaus V.H., Rego V.M., Di Cecco V., Busch V., Fontana V., Piscova V., Carbonell V., Ochoa V., Bretagnolle V., Maire V., Farjalla V., Zhou W., Luo W., McDowell W.H., Hu Y., Utsumi Y., Kominami Y., Zaika Y., Rozhkov Y., Kotroczo Z., Toth Z., and Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Subjects: DYNAMICS, 010504 meteorology & atmospheric sciences, Biome, Biochimie, Biologie Moléculaire, Carbon turnover, 01 natural sciences, CARBON, Waste Management and Disposal, ComputingMilieux_MISCELLANEOUS, CLIMATE-CHANGE, биомы, Tea bag, Green tea, Rooibos tea, Carbon turnover, TeaComposition initiative, 04 agricultural and veterinary sciences, Pollution, Environmental chemistry, [SDE]Environmental Sciences, Terrestrial ecosystem, Life Sciences & Biomedicine, Biologie, TRAITS, Rooibos tea, IMPACTS, Environmental Engineering, почвенные процессы, chemistry.chemical_element, Climate change, Environmental Sciences & Ecology, Ingénierie de l'environnement, Green tea, Tea bag, TeaComposition initiative, Ecology and Environment, Atmosphere, подстилки, Environmental Chemistry, Ecosystem, RATES, 0105 earth and related environmental sciences, оборот углерода, Science & Technology, Tea composition initiative, FEEDBACK, 15. Life on land, Decomposition, влияние климата, TERRESTRIAL ECOSYSTEMS, MODEL, экосистемы, chemistry, 13. Climate action, PATTERNS, 040103 agronomy & agriculture, Litter, 0401 agriculture, forestry, and fisheries, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 500 Naturwissenschaften und Mathematik::570 Biowissenschaften, Biologie::577 Ökologie, Carbon, Environmental Sciences
Abstract: Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from -9 to +26 °C MAT and from 60 to 3113 mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained
Published: 2018
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12. High arctic heath soil respiration and biogeochemical dynamics during summer and autumn freeze‐in – effects of long‐term enhanced water and nutrient supply

Author: Niels Martin Schmidt, Casper T. Christiansen, Sarah Hagel Svendsen, and Anders Michelsen
Subjects: Global and Planetary Change, Biogeochemical cycle, Ecology, Soil organic matter, Soil biology, Soil chemistry, Soil respiration, Nutrient, Agronomy, Soil water, Environmental Chemistry, Environmental science, Ecosystem, General Environmental Science
Abstract: In High Arctic NE Greenland, temperature and precipitation are predicted to increase during this century, however, relatively little information is available on the role of increased water supply on soil CO 2 efflux in dry, high arctic ecosystems. We measured soil respiration (Rsoil) in summer and autumn of 2009 in combination with microbial biomass and nutrient availability during autumn freeze-in at a dry, open heath in Zackenberg, NE Greenland. This tundra site has been subject to fully factorial manipulation consisting of increased soil water supply for 14 years, and occasional nitrogen (N) addition in pulses. Summer watering enhanced Rsoil during summer, but decreased Rsoil in the following autumn. We speculate that this is due to intensified depletion of recently fixed plant carbon by soil organisms. Hence, autumn soil microbial activity seems tightly linked to growing season plant production through plant-associated carbon pools. Nitrogen addition alone consistently increased Rsoil, but when water and nitrogen were added in combination, autumn Rsoil declined similarly to when water was added alone. Despite several freeze-thaw events, the microbial biomass carbon (C) remained constant until finally being reduced by ~60% in late September. In spite of significantly reduced microbial biomass C and phosphorus (P), microbial N did not change. This suggests N released from dead microbes was quickly assimilated by surviving microbes. We observed no change in soil organic matter content after 14 years of environmental manipulations, suggesting high ecosystem resistance to environmental changes.
Published: 2012
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13. High Arctic dry heath CO2 exchange during the early cold season

Author: Anders Michelsen, Casper T. Christiansen, and Niels Martin Schmidt
Subjects: Ecology, Climate change, chemistry.chemical_element, Tundra, Nutrient, Agronomy, Arctic, chemistry, Environmental Chemistry, Environmental science, Terrestrial ecosystem, Ecosystem, Ecosystem respiration, Carbon, Ecology, Evolution, Behavior and Systematics
Abstract: Climate change may alter the terrestrial ecosystem carbon balance in the Arctic, and previous studies have emphasized the importance of cold season gas exchange when considering the annual carbon balance. Here, we examined gross ecosystem production (GEP), ecosystem respiration (R eco) and net ecosystem exchange (NEE) during autumn at a high arctic dry open heath, over a period where air temperatures decreased from +9.8 to −16.5°C. GEP declined by 95–100% during autumn but GEP significantly different from 0 was measured on October 8 despite sub-zero temperatures. R eco declined by 90% and dominated NEE throughout the study as the ecosystem on all measurement days was a source of atmospheric CO2. We estimated net September carbon losses (NEE) to be 17 g CO2 m−2, emphasizing the importance of autumn in relation to annual carbon budgets. The study site has been subjected to 14 summers of water addition, and occasional pulses of nitrogen (N) addition in a fully factorial design. N addition enhanced GEP up to 17-fold during September, although there was no effect in October when GEP was very low. Summer water addition decreased autumn R eco by up to 25%. Both N amendment and water addition decreased carbon loss, that is, increased NEE; N amendment increased NEE on all dates by 13–64% whereas water addition increased NEE by 20–54% late in September and onward, demonstrating the importance of nutrient and water availability on carbon balance in high arctic tundra, also during the autumn freeze-in.
Published: 2012
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13 results on '"Casper T. Christiansen"'

1. Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter

2. Explicitly modelling microtopography in permafrost landscapes in a land-surface model (JULES vn5.4_microtopography)

3. Effects of Climate and Atmospheric Nitrogen Deposition on Early to Mid-Term Stage Litter Decomposition Across Biomes

4. Abrupt thaw enhances annual global warming potential of an actively degrading permafrost peatland

5. Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems

6. Decomposition of Senesced Leaf Litter is Faster in Tall Compared to Low Birch Shrub Tundra

7. Long-term deepened snow promotes tundra evergreen shrub growth and summertime ecosystem net CO2gain but reduces soil carbon and nutrient pools

8. Examination of Soil Microbial Communities After Permafrost Thaw Subsequent to an Active Layer Detachment in the High Arctic

9. Large loss of CO2 in winter observed across the northern permafrost region

10. Long-term experimentally deepened snow decreases growing-season respiration in a low- and high-arctic tundra ecosystem

11. Early stage litter decomposition across biomes

12. High arctic heath soil respiration and biogeochemical dynamics during summer and autumn freeze‐in – effects of long‐term enhanced water and nutrient supply

13. High Arctic dry heath CO2 exchange during the early cold season

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13 results on '"Casper T. Christiansen"'

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