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101. Assessing the Potential for Mobilization of Old Soil Carbon After Permafrost Thaw: A Synthesis of 14C Measurements From the Northern Permafrost Region

Author

Estop‐Aragonés, Cristian, primary, Olefeldt, David, additional, Abbott, Benjamin W., additional, Chanton, Jeffrey P., additional, Czimczik, Claudia I., additional, Dean, Joshua F., additional, Egan, Jocelyn E., additional, Gandois, Laure, additional, Garnett, Mark H., additional, Hartley, Iain P., additional, Hoyt, Alison, additional, Lupascu, Massimo, additional, Natali, Susan M., additional, O'Donnell, Jonathan A., additional, Raymond, Peter A., additional, Tanentzap, Andrew J., additional, Tank, Suzanne E., additional, Schuur, Edward A. G., additional, Turetsky, Merritt, additional, and Anthony, Katey Walter, additional

Published
2020
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103. Supplementary material to "Investigating the sensitivity of soil respiration to recent snow cover changes in Alaska using a satellite-based permafrost carbon model"

Author

Yi, Yonghong, primary, Kimball, John S., additional, Watts, Jennifer D., additional, Natali, Susan M., additional, Zona, Donatella, additional, Liu, Junjie, additional, Ueyama, Masahito, additional, Kobayashi, Hideki, additional, Oechel, Walter, additional, and Miller, Charles E., additional

Published
2020
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105. Large loss of CO2 in winter observed across the northern permafrost region (vol 9, pg 852, 2019)

Author

Natali, Susan M., Watts, Jennifer D., Rogers, Brendan M., Potter, Stefano, Ludwig, Sarah M., Selbmann, Anne-Katrin, Sullivan, Patrick F., Abbott, Benjamin W., Arndt, Kyle A., Birch, Leah, Bjorkman, Mats P., Bloom, A. Anthony, Celis, Gerardo, Christensen, Torben R., Christiansen, Casper T., Commane, Roisin, Cooper, Elisabeth J., Crill, Patrick, Czimczik, Claudia, Davydov, Sergey, Du, Jinyang, Egan, Jocelyn E., Elberling, Bo, Euskirchen, Eugenie S., Friborg, Thomas, Genet, Helene, Gockede, Mathias, Goodrich, Jordan P., Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E., Jastrow, Julie D., Kalhori, Aram A. M., Kim, Yongwon, Kimball, John S., Kutzbach, Lars, Lara, Mark J., Larsen, Klaus S., Lee, Bang-Yong, Liu, Zhihua, Loranty, Michael M., Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A. David, Michelsen, Anders, Minions, Christina, Oechel, Walter C., Olefeldt, David, Parmentier, Frans-Jan W., Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, Schmidt, Niels M., Schuur, Edward A. G., Semenchuk, Philipp R., Shaver, Gaius, Sonnentag, Oliver, Starr, Gregory, Treat, Claire C., Waldrop, Mark P., Wang, Yihui, Welker, Jeffrey, Wille, Christian, Xu, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, and Zona, Donatella

Published
2019
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106. Author Correction:Large loss of CO2 in winter observed across the northern permafrost region (Nature Climate Change, (2019), 9, 11, (852-857), 10.1038/s41558-019-0592-8)

Author

Natali, Susan M., Watts, Jennifer D., Rogers, Brendan M., Potter, Stefano, Ludwig, Sarah M., Selbmann, Anne Katrin, Sullivan, Patrick F., Abbott, Benjamin W., Arndt, Kyle A., Birch, Leah, Björkman, Mats P., Bloom, A. Anthony, Celis, Gerardo, Christensen, Torben R., Christiansen, Casper T., Commane, Roisin, Cooper, Elisabeth J., Crill, Patrick, Czimczik, Claudia, Davydov, Sergey, Du, Jinyang, Egan, Jocelyn E., Elberling, Bo, Euskirchen, Eugenie S., Friborg, Thomas, Genet, Hélène, Göckede, Mathias, Goodrich, Jordan P., Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E., Jastrow, Julie D., Kalhori, Aram A.M., Kim, Yongwon, Kimball, John S., Kutzbach, Lars, Lara, Mark J., Larsen, Klaus S., Lee, Bang Yong, Liu, Zhihua, Loranty, Michael M., Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A. David, Michelsen, Anders, Minions, Christina, Oechel, Walter C., Olefeldt, David, Parmentier, Frans Jan W., Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, Schmidt, Niels M., Schuur, Edward A.G., Semenchuk, Philipp R., Shaver, Gaius, Sonnentag, Oliver, Starr, Gregory, Treat, Claire C., Waldrop, Mark P., Wang, Yihui, Welker, Jeffrey, Wille, Christian, Xu, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, and Zona, Donatella

Abstract

In the version of this Letter originally published online, the descriptions of the solid blue and red lines in Fig. 4 were switched in the caption; the text should have read “Solid lines represent BRT-modelled results up to 2100 under RCP 4.5 (blue solid line) and RCP 8.5 (red solid line), with bootstrapped 95% confidence intervals indicated by shading.” This has now been corrected in all online versions.

Published
2019
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107. Large loss of CO2 in winter observed across the northern permafrost region:[incl. correction]

Author

Natali, Susan M., Watts, Jennifer D., Rogers, Brendan M., Potter, Stefano, Ludwig, Sarah M., Selbmann, Anne-Katrin, Sullivan, Patrick F., Abbott, Benjamin W., Arndt, Kyle A., Birch, Leah, Björkman, Mats P., Bloom, A. Anthony, Celis, Gerardo, Christensen, Torben R., Christiansen, Casper T., Commane, Roisin, Cooper, Elisabeth J., Crill, Patrick, Czimczik, Claudia, Davydov, Sergey P., Du, Jinyang, Egan, Jocelyn E., Elberling, Bo, Euskirchen, Eugenie S., Friborg, Thomas, Genet, Hélène, Göckede, Mathias, Goodrich, Jordan P., Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E., Jastrow, Julie D., Kalhori, Aram A. M., Kim, Yongwon, Kimball, John S., Kutzbach, Lars, Lara, J. Mark, Larsen, Klaus Steenberg, Lee, Bang-Yong, Liu, Zhihua, Loranty, Michael M., Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A. David, Michelsen, Anders, Minions, Christina, Oechel, Walter C., Olefeldt, David, Parmentier, Frans-Jan W., Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, M. Schmidt, Niels, Schuur, Edward A.G., Semenchuk, Philipp R., Shaver, Gaius R., Sonnentag, Oliver, Starr, Gregory, Treat, Claire C., Waldrop, Mark P., Wang, Yihui, Welker, Jeffrey M., Wille, Christian, Xue, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, and Zona, Donatella

Published
2019
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108. JS-supplementary – Supplemental material for Temperature-controlled tundra fire severity and frequency during the last millennium in the Yukon-Kuskokwim Delta, Alaska

Author

Jarunetr Sae-Lim, Russell, James M, Vachula, Richard S, Holmes, Robert M, Mann, Paul J, Schade, John D, and Natali, Susan M

Subjects
History, Geography
Abstract

Supplemental material, JS-supplementary for Temperature-controlled tundra fire severity and frequency during the last millennium in the Yukon-Kuskokwim Delta, Alaska by Jarunetr Sae-Lim, James M Russell, Richard S Vachula, Robert M Holmes, Paul J Mann, John D Schade and Susan M Natali in The Holocene

Published
2019
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109. Large loss of CO2 in winter observed across the northern permafrost region

Author

Natali, Susan M., Watts, Jennifer D., Rogers, Brendan M., Potter, Stefano, Ludwig, Sarah M., Selbmann, Anne-Katrin, Sullivan, Patrick F., Abbott, Benjamin W., Arndt, Kyle A., Birch, Leah, Björkman, Mats P., Bloom, A. Anthony, Celis, Gerardo, Christensen, Torben R., Christiansen, Casper T., Commane, Roisin, Cooper, Elisabeth J., Crill, Patrick, Czimczik, Claudia, Davydov, Sergey, Du, Jinyang, Egan, Jocelyn E., Elberling, Bo, Euskirchen, Eugenie S., Friborg, Thomas, Genet, Hélène, Göckede, Mathias, Goodrich, Jordan P., Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E., Jastrow, Julie D., Kalhori, Aram A. M., Kim, Yongwon, Kimball, John S., Kutzbach, Lars, Lara, Mark J., Larsen, Klaus S., Lee, Bang-Yong, Liu, Zhihua, Loranty, Michael M., Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A. David, Michelsen, Anders, Minions, Christina, Oechel, Walter C., Olefeldt, David, Parmentier, Frans-Jan W., Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, Schmidt, Niels M., Schuur, Edward A. G., Semenchuk, Philipp R., Shaver, Gaius, Sonnentag, Oliver, Starr, Gregory, Treat, Claire C., Waldrop, Mark P., Wang, Yihui, Welker, Jeffrey, Wille, Christian, Xu, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, Zona, Donatella, Natali, Susan M., Watts, Jennifer D., Rogers, Brendan M., Potter, Stefano, Ludwig, Sarah M., Selbmann, Anne-Katrin, Sullivan, Patrick F., Abbott, Benjamin W., Arndt, Kyle A., Birch, Leah, Björkman, Mats P., Bloom, A. Anthony, Celis, Gerardo, Christensen, Torben R., Christiansen, Casper T., Commane, Roisin, Cooper, Elisabeth J., Crill, Patrick, Czimczik, Claudia, Davydov, Sergey, Du, Jinyang, Egan, Jocelyn E., Elberling, Bo, Euskirchen, Eugenie S., Friborg, Thomas, Genet, Hélène, Göckede, Mathias, Goodrich, Jordan P., Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E., Jastrow, Julie D., Kalhori, Aram A. M., Kim, Yongwon, Kimball, John S., Kutzbach, Lars, Lara, Mark J., Larsen, Klaus S., Lee, Bang-Yong, Liu, Zhihua, Loranty, Michael M., Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A. David, Michelsen, Anders, Minions, Christina, Oechel, Walter C., Olefeldt, David, Parmentier, Frans-Jan W., Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, Schmidt, Niels M., Schuur, Edward A. G., Semenchuk, Philipp R., Shaver, Gaius, Sonnentag, Oliver, Starr, Gregory, Treat, Claire C., Waldrop, Mark P., Wang, Yihui, Welker, Jeffrey, Wille, Christian, Xu, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, and Zona, Donatella

Abstract

Recent warming in the Arctic, which has been amplified during the winter(1-3), 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 estimates(5,6). 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.

Published
2019
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110. Vegetation indices do not capture forest cover variation in Upland Siberian Larch Forests

Author

Loranty, Michael M., Davydov, Sergey P., Kropp, Heather, Alexander, Heather D., Mack, Michelle C., Natali, Susan M., Zimov, Nikita S., Loranty, Michael M., Davydov, Sergey P., Kropp, Heather, Alexander, Heather D., Mack, Michelle C., Natali, Susan M., and Zimov, Nikita S.

Abstract

© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Loranty, Michael M.; Davydov, Sergey P.; Kropp, Heather; Alexander, Heather D.; Mack, Michelle C.; Natali, Susan M.; Zimov, Nikita S. 2018. "Vegetation Indices Do Not Capture Forest Cover Variation in Upland Siberian Larch Forests." Remote Sens. 10, no. 11: 1686, doi:10.3390/rs10111686., Boreal forests are changing in response to climate, with potentially important feedbacks to regional and global climate through altered carbon cycle and albedo dynamics. These feedback processes will be affected by vegetation changes, and feedback strengths will largely rely on the spatial extent and timing of vegetation change. Satellite remote sensing is widely used to monitor vegetation dynamics, and vegetation indices (VIs) are frequently used to characterize spatial and temporal trends in vegetation productivity. In this study we combine field observations of larch forest cover across a 25 km2 upland landscape in northeastern Siberia with high-resolution satellite observations to determine how the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) are related to forest cover. Across 46 forest stands ranging from 0% to 90% larch canopy cover, we find either no change, or declines in NDVI and EVI derived from PlanetScope CubeSat and Landsat data with increasing forest cover. In conjunction with field observations of NDVI, these results indicate that understory vegetation likely exerts a strong influence on vegetation indices in these ecosystems. This suggests that positive decadal trends in NDVI in Siberian larch forests may correspond primarily to increases in understory productivity, or even to declines in forest cover. Consequently, positive NDVI trends may be associated with declines in terrestrial carbon storage and increases in albedo, rather than increases in carbon storage and decreases in albedo that are commonly assumed. Moreover, it is also likely that important ecological changes such as large changes in forest density or variable forest regrowth after fire are not captured by long-term NDVI trends., We thank numerous undergraduate and graduate research assistants, and Polaris Project participants for field and lab assistance. We thank the staff and scientists at the Northeast Science Station for logistical and field support. Lastly, we thank the editors and six anonymous reviewers whose comments helped to improve this paper.

Published
2019

111. Direct observation of permafrost degradation and rapid soil carbon loss in tundra

Author

Plaza de Carlos, César, Pegoraro, Elaine, Bracho, Rosvel, Celis, Gerardo, Crummer, Kathryn G., Hutchings, Jack A., Hicks Pries, Caitlin E., Mauritz, Marguerite, Natali, Susan M., Salmon, Verity G., Schädel, Christina, Webb, Elizabeth E., Schuur, Edward A. G., Plaza de Carlos, César, Pegoraro, Elaine, Bracho, Rosvel, Celis, Gerardo, Crummer, Kathryn G., Hutchings, Jack A., Hicks Pries, Caitlin E., Mauritz, Marguerite, Natali, Susan M., Salmon, Verity G., Schädel, Christina, Webb, Elizabeth E., and Schuur, Edward A. G.

Published
2019

112. Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties.

Author

Virkkala, Anna‐Maria, Aalto, Juha, Rogers, Brendan M., Tagesson, Torbern, Treat, Claire C., Natali, Susan M., Watts, Jennifer D., Potter, Stefano, Lehtonen, Aleksi, Mauritz, Marguerite, Schuur, Edward A. G., Kochendorfer, John, Zona, Donatella, Oechel, Walter, Kobayashi, Hideki, Humphreys, Elyn, Goeckede, Mathias, Iwata, Hiroki, Lafleur, Peter M., and Euskirchen, Eugenie S.

Subjects
TUNDRAS, CARBON cycle, STATISTICAL ensembles, STATISTICAL models, PERMAFROST ecosystems, FLUX (Energy), GROWING season, MACHINE performance
Abstract

The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink‐source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990–2015 from 148 terrestrial high‐latitude (i.e., tundra and boreal) sites to analyze the spatial patterns and drivers of CO2 fluxes and test the accuracy and uncertainty of different statistical models. CO2 fluxes were upscaled at relatively high spatial resolution (1 km2) across the high‐latitude region using five commonly used statistical models and their ensemble, that is, the median of all five models, using climatic, vegetation, and soil predictors. We found the performance of machine learning and ensemble predictions to outperform traditional regression methods. We also found the predictive performance of NEE‐focused models to be low, relative to models predicting GPP and ER. Our data compilation and ensemble predictions showed that CO2 sink strength was larger in the boreal biome (observed and predicted average annual NEE −46 and −29 g C m−2 yr−1, respectively) compared to tundra (average annual NEE +10 and −2 g C m−2 yr−1). This pattern was associated with large spatial variability, reflecting local heterogeneity in soil organic carbon stocks, climate, and vegetation productivity. The terrestrial ecosystem CO2 budget, estimated using the annual NEE ensemble prediction, suggests the high‐latitude region was on average an annual CO2 sink during 1990–2015, although uncertainty remains high. [ABSTRACT FROM AUTHOR]

Published
2021
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113. The ABCflux database: Arctic-Boreal CO2 flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems.

Author

Virkkala, Anna-Maria, Natali, Susan M., Rogers, Brendan M., Watts, Jennifer D., Savage, Kathleen, Connon, Sara June, Mauritz, Marguerite, Schuur, Edward A. G., Peter, Darcy, Minions, Christina, Nojeim, Julia, Commane, Roisin, Emmerton, Craig A., Goeckede, Mathias, Helbig, Manuel, Holl, David, Iwata, Hiroki, Kobayashi, Hideki, Kolari, Pasi, and López-Blanco, Efrén

Subjects
*TUNDRAS, *FLUX (Energy), *SOIL air, *TEMPORAL databases, *SOIL temperature, *ECOSYSTEMS, *REMOTE sensing
Abstract

Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic-Boreal Zone (ABZ) have provided valuable information, but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic-Boreal CO2 fluxes (ABCflux) that aggregates in-situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity and ecosystem respiration. The data span from 1989 to 2020 with over 70 supporting variables that describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures) and flux measurement techniques. Here, we describe these variables, the spatial and temporal distribution of observations, the main strengths and limitations of the database, and the potential research opportunities it enables. In total, ABCflux includes 244 sites and 6309 monthly observations; 136 sites and 2217 monthly observations represent tundra, and 108 sites and 4092 observations represent the boreal biome. The database includes fluxes estimated with chamber (19 % of the monthly observations), snow diffusion (3 %) and eddy covariance (78 %) techniques. The largest number of observations were collected during the climatological summer (June-August; 32 %), and fewer observations were available for autumn (September-October; 25 %), winter (December-February; 18 %), and spring (March-May; 25 %). ABCflux can be used in a wide array of empirical, remote sensing and modeling studies to improve understanding of the regional and temporal variability in CO2 fluxes, and to better estimate the terrestrial ABZ CO2 budget. ABCflux is openly and freely available online (https://doi.org/10.3334/ORNLDAAC/1934, Virkkala et al., 2021a). [ABSTRACT FROM AUTHOR]

Published
2021
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114. Large loss of CO2 in winter observed across the northern permafrost region

Author

Natali, Susan M., primary, Watts, Jennifer D., additional, Rogers, Brendan M., additional, Potter, Stefano, additional, Ludwig, Sarah M., additional, Selbmann, Anne-Katrin, additional, Sullivan, Patrick F., additional, Abbott, Benjamin W., additional, Arndt, Kyle A., additional, Birch, Leah, additional, Björkman, Mats P., additional, Bloom, A. Anthony, additional, Celis, Gerardo, additional, Christensen, Torben R., additional, Christiansen, Casper T., additional, Commane, Roisin, additional, Cooper, Elisabeth J., additional, Crill, Patrick, additional, Czimczik, Claudia, additional, Davydov, Sergey, additional, Du, Jinyang, additional, Egan, Jocelyn E., additional, Elberling, Bo, additional, Euskirchen, Eugenie S., additional, Friborg, Thomas, additional, Genet, Hélène, additional, Göckede, Mathias, additional, Goodrich, Jordan P., additional, Grogan, Paul, additional, Helbig, Manuel, additional, Jafarov, Elchin E., additional, Jastrow, Julie D., additional, Kalhori, Aram A. M., additional, Kim, Yongwon, additional, Kimball, John S., additional, Kutzbach, Lars, additional, Lara, Mark J., additional, Larsen, Klaus S., additional, Lee, Bang-Yong, additional, Liu, Zhihua, additional, Loranty, Michael M., additional, Lund, Magnus, additional, Lupascu, Massimo, additional, Madani, Nima, additional, Malhotra, Avni, additional, Matamala, Roser, additional, McFarland, Jack, additional, McGuire, A. David, additional, Michelsen, Anders, additional, Minions, Christina, additional, Oechel, Walter C., additional, Olefeldt, David, additional, Parmentier, Frans-Jan W., additional, Pirk, Norbert, additional, Poulter, Ben, additional, Quinton, William, additional, Rezanezhad, Fereidoun, additional, Risk, David, additional, Sachs, Torsten, additional, Schaefer, Kevin, additional, Schmidt, Niels M., additional, Schuur, Edward A. G., additional, Semenchuk, Philipp R., additional, Shaver, Gaius, additional, Sonnentag, Oliver, additional, Starr, Gregory, additional, Treat, Claire C., additional, Waldrop, Mark P., additional, Wang, Yihui, additional, Welker, Jeffrey, additional, Wille, Christian, additional, Xu, Xiaofeng, additional, Zhang, Zhen, additional, Zhuang, Qianlai, additional, and Zona, Donatella, additional

Published
2019
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116. Direct observation of permafrost degradation and rapid soil carbon loss in tundra

Author

Plaza, César, primary, Pegoraro, Elaine, additional, Bracho, Rosvel, additional, Celis, Gerardo, additional, Crummer, Kathryn G., additional, Hutchings, Jack A., additional, Hicks Pries, Caitlin E., additional, Mauritz, Marguerite, additional, Natali, Susan M., additional, Salmon, Verity G., additional, Schädel, Christina, additional, Webb, Elizabeth E., additional, and Schuur, Edward A. G., additional

Published
2019
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118. Drainage enhances modern soil carbon contribution but reduces old soil carbon contribution to ecosystem respiration in tundra ecosystems

Author

Kwon, Min Jung, primary, Natali, Susan M., additional, Hicks Pries, Caitlin E., additional, Schuur, Edward A. G., additional, Steinhof, Axel, additional, Crummer, K. Grace, additional, Zimov, Nikita, additional, Zimov, Sergey A., additional, Heimann, Martin, additional, Kolle, Olaf, additional, and Göckede, Mathias, additional

Published
2019
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119. Strengthened scientific support for the Endangerment Finding for atmospheric greenhouse gases

Author

Duffy, Philip B., primary, Field, Christopher B., additional, Diffenbaugh, Noah S., additional, Doney, Scott C., additional, Dutton, Zoe, additional, Goodman, Sherri, additional, Heinzerling, Lisa, additional, Hsiang, Solomon, additional, Lobell, David B., additional, Mickley, Loretta J., additional, Myers, Samuel, additional, Natali, Susan M., additional, Parmesan, Camille, additional, Tierney, Susan, additional, and Williams, A. Park, additional

Published
2019
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120. Environmental and taxonomic controls of carbon and oxygen stable isotope composition in Sphagnum across broad climatic and geographic ranges

Author

Granath, Gustaf, Rydin, Håkan, Baltzer, Jennifer L., Bengtsson, Fia, Boncek, Nicholas, Bragazza, Luca, Bu, Zhao-Jun, Caporn, Simon J. M., Dorrepaal, Ellen, Galanina, Olga, Galka, Mariusz, Ganeva, Anna, Gillikin, David P., Goia, Irina, Goncharova, Nadezhda, Hajek, Michal, Haraguchi, Akira, Harris, Lorna I., Humphreys, Elyn, Jirousek, Martin, Kajukalo, Katarzyna, Karofeld, Edgar, Koronatova, Natalia G., Kosykh, Natalia P., Lamentowicz, Mariusz, Lapshina, Elena, Limpens, Juul, Linkosalmi, Maiju, Ma, Jin-Ze, Mauritz, Marguerite, Munir, Tariq M., Natali, Susan M., Natcheva, Rayna, Noskova, Maria, Payne, Richard J., Pilkington, Kyle, Robinson, Sean, Robroek, Bjorn J. M., Rochefort, Line, Singer, David, Stenoien, Hans K., Tuittila, Eeva-Stiina, Vellak, Kai, Verheyden, Anouk, Waddington, James Michael, Rice, Steven K., Granath, Gustaf, Rydin, Håkan, Baltzer, Jennifer L., Bengtsson, Fia, Boncek, Nicholas, Bragazza, Luca, Bu, Zhao-Jun, Caporn, Simon J. M., Dorrepaal, Ellen, Galanina, Olga, Galka, Mariusz, Ganeva, Anna, Gillikin, David P., Goia, Irina, Goncharova, Nadezhda, Hajek, Michal, Haraguchi, Akira, Harris, Lorna I., Humphreys, Elyn, Jirousek, Martin, Kajukalo, Katarzyna, Karofeld, Edgar, Koronatova, Natalia G., Kosykh, Natalia P., Lamentowicz, Mariusz, Lapshina, Elena, Limpens, Juul, Linkosalmi, Maiju, Ma, Jin-Ze, Mauritz, Marguerite, Munir, Tariq M., Natali, Susan M., Natcheva, Rayna, Noskova, Maria, Payne, Richard J., Pilkington, Kyle, Robinson, Sean, Robroek, Bjorn J. M., Rochefort, Line, Singer, David, Stenoien, Hans K., Tuittila, Eeva-Stiina, Vellak, Kai, Verheyden, Anouk, Waddington, James Michael, and Rice, Steven K.

Abstract

Rain-fed peatlands are dominated by peat mosses (Sphagnum sp.), which for their growth depend on nutrients, water and CO2 uptake from the atmosphere. As the isotopic composition of carbon (C-12(,)13) and oxygen (O-16(,)18) of these Sphagnum mosses are affected by environmental conditions, Sphagnum tissue accumulated in peat constitutes a potential long-term archive that can be used for climate reconstruction. However, there is inadequate understanding of how isotope values are influenced by environmental conditions, which restricts their current use as environmental and palaeoenvironmental indicators. Here we tested (i) to what extent C and O isotopic variation in living tissue of Sphagnum is speciesspecific and associated with local hydrological gradients, climatic gradients (evapotranspiration, temperature, precipitation) and elevation; (ii) whether the C isotopic signature can be a proxy for net primary productivity (NPP) of Sphagnum; and (iii) to what extent Sphagnum tissue delta O-18 tracks the delta O-18 isotope signature of precipitation. In total, we analysed 337 samples from 93 sites across North America and Eurasia us ing two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) common to the Holarctic realm. There were differences in delta C-13 values between species. For S. magellanicum delta C-13 decreased with increasing height above the water table (HWT, R-2 = 17 %) and was positively correlated to productivity (R-2 = 7 %). Together these two variables explained 46 % of the between-site variation in delta C-13 values. For S. fuscum, productivity was the only significant predictor of delta C-13 but had low explanatory power (total R-2 = 6 %). For delta O-18 values, approximately 90 % of the variation was found between sites. Globally modelled annual delta O-18 values in precipitation explained 69 % of the between-site variation in tissue delta O-18. S. magellanicum showed lower delta O-18 enrichment than S. fuscum (-0.83 %0 lower). Eleva

Published
2018
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121. Assessing the Potential for Mobilization of Old Soil Carbon After Permafrost Thaw: A Synthesis of 14C Measurements From the Northern Permafrost Region.

Author

Estop‐Aragonés, Cristian, Olefeldt, David, Abbott, Benjamin W., Chanton, Jeffrey P., Czimczik, Claudia I., Dean, Joshua F., Egan, Jocelyn E., Gandois, Laure, Garnett, Mark H., Hartley, Iain P., Hoyt, Alison, Lupascu, Massimo, Natali, Susan M., O'Donnell, Jonathan A., Raymond, Peter A., Tanentzap, Andrew J., Tank, Suzanne E., Schuur, Edward A. G., Turetsky, Merritt, and Anthony, Katey Walter

Subjects
TUNDRAS, PERMAFROST, CARBON in soils, COLLOIDAL carbon, THAWING, ECOLOGICAL disturbances
Abstract

The magnitude of future emissions of greenhouse gases from the northern permafrost region depends crucially on the mineralization of soil organic carbon (SOC) that has accumulated over millennia in these perennially frozen soils. Many recent studies have used radiocarbon (14C) to quantify the release of this "old" SOC as CO2 or CH4 to the atmosphere or as dissolved and particulate organic carbon (DOC and POC) to surface waters. We compiled ~1,900 14C measurements from 51 sites in the northern permafrost region to assess the vulnerability of thawing SOC in tundra, forest, peatland, lake, and river ecosystems. We found that growing season soil 14C‐CO2 emissions generally had a modern (post‐1950s) signature, but that well‐drained, oxic soils had increased CO2 emissions derived from older sources following recent thaw. The age of CO2 and CH4 emitted from lakes depended primarily on the age and quantity of SOC in sediments and on the mode of emission, and indicated substantial losses of previously frozen SOC from actively expanding thermokarst lakes. Increased fluvial export of aged DOC and POC occurred from sites where permafrost thaw caused soil thermal erosion. There was limited evidence supporting release of previously frozen SOC as CO2, CH4, and DOC from thawing peatlands with anoxic soils. This synthesis thus suggests widespread but not universal release of permafrost SOC following thaw. We show that different definitions of "old" sources among studies hamper the comparison of vulnerability of permafrost SOC across ecosystems and disturbances. We also highlight opportunities for future 14C studies in the permafrost region. Key Points: We compiled ~1,900 14C measurements of CO2, CH4, DOC, and POC from the northern permafrost regionOld carbon release increases in thawed oxic soils (CO2), thermokarst lakes (CH4 and CO2), and headwaters with thermal erosion (DOC and POC)Simultaneous and year‐long 14C analyses of CO2, CH4, DOC, and POC are needed to assess the vulnerability of permafrost carbon across ecosystems [ABSTRACT FROM AUTHOR]

Published
2020
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122. Investigating the sensitivity of soil respiration to recent snow cover changes in Alaska using a satellite-based permafrost carbon model.

Author

Yonghong Yi, Kimball, John S., Watts, Jennifer D., Natali, Susan M., Zona, Donatella, Liu, Junjie, Ueyama, Masahito, Hideki Kobayashi, Oechel, Walter, and Miller, Charles E.

Subjects
TUNDRAS, SOIL respiration, SNOW cover, HETEROTROPHIC respiration, PERMAFROST, CLIMATE feedbacks, SEASONAL temperature variations
Abstract

The contribution of soil heterotrophic respiration to the boreal-Arctic carbon (CO2) cycle and its potential feedback to climate change remain poorly quantified. We developed a remote sensing driven permafrost carbon model at intermediate scale (~ 1 km) to investigate how environmental factors affect the magnitude and seasonality of soil heterotrophic respiration in Alaska. The permafrost carbon model simulates snow and soil thermal dynamics, and accounts for vertical soil carbon transport and decomposition at depths up to 3 m below surface. Model outputs include soil temperature profiles and carbon fluxes at 1-km resolution spanning the recent satellite era (2001-2017) across Alaska. Comparisons with eddy covariance tower measurements show that the model captures the seasonality of carbon fluxes, with favorable accuracy in predicting net ecosystem CO2 exchange (NEE) in both tundra (R > 0.8, RMSE = 0.34 g C m-2 d-1) and boreal forest (R > 0.73, RMSE = 0.51 g C m-2 d-1). Benchmark assessments using two regional in-situ datasets indicate that the model captures the complex influence of snow insulation on soil temperature, and the temperature sensitivity of cold-season soil respiration. Across Alaska, we find that seasonal snow cover imposes strong controls on the contribution from different soil depths to total soil carbon emissions. Earlier snow melt in spring promotes deeper soil warming and enhances the contribution of deeper soils to total soil respiration during the later growing season, thereby reducing net ecosystem carbon uptake. Early cold-season soil respiration is closely linked to the number of snow-free days after land surface freezes (R = -0.48, p < 0.1), i.e. the delay in snow onset relative to surface freeze onset. Recent trends toward earlier autumn snow onset in northern Alaska promote a longer zero-curtain period and enhanced cold-season respiration. In contrast, southwestern Alaska shows a strong reduction in the number of snow-free days after land surface freeze onset, leading to earlier soil freezing and a large reduction in cold-season soil respiration. Our results also show non-negligible influences of sub-grid variability of surface conditions on the model simulated CO2 seasonal cycle, especially during the early cold season at 10-km scale. Our results demonstrate the critical role of snow cover affecting the seasonality of soil temperature and respiration and highlight the challenges of incorporating these complex processes into future projections of boreal-Arctic carbon cycle. [ABSTRACT FROM AUTHOR]

Published
2020
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123. Carbon Thaw Rate Doubles When Accounting for Subsidence in a Permafrost Warming Experiment.

Author

Rodenhizer, Heidi, Ledman, Justin, Mauritz, Marguerite, Natali, Susan M., Pegoraro, Elaine, Plaza, César, Romano, Emily, Schädel, Christina, Taylor, Meghan, and Schuur, Edward

Subjects
PERMAFROST, LAND subsidence, CARBON in soils, GROUNDWATER, SOIL depth
Abstract

Permafrost thaw is typically measured with active layer thickness, or the maximum seasonal thaw measured from the ground surface. However, previous work has shown that this measurement alone fails to account for ground subsidence and therefore underestimates permafrost thaw. To determine the impact of subsidence on observed permafrost thaw and thawed soil carbon stocks, we quantified subsidence using high‐accuracy GPS and identified its environmental drivers in a permafrost warming experiment near the southern limit of permafrost in Alaska. With permafrost temperatures near 0°C, 10.8 cm of subsidence was observed in control plots over 9 years. Experimental air and soil warming increased subsidence by five times and created inundated microsites. Across treatments, ice and soil loss drove 85–91% and 9–15% of subsidence, respectively. Accounting for subsidence, permafrost thawed between 19% (control) and 49% (warming) deeper than active layer thickness indicated, and the amount of newly thawed carbon within the active layer was between 37% (control) and 113% (warming) greater. As additional carbon thaws as the active layer deepens, carbon fluxes to the atmosphere and lateral transport of carbon in groundwater could increase. The magnitude of this impact is uncertain at the landscape scale, though, due to limited subsidence measurements. Therefore, to determine the full extent of permafrost thaw across the circumpolar region and its feedback on the carbon cycle, it is necessary to quantify subsidence more broadly across the circumpolar region. Plain Language Summary: Permafrost soils, which are perennially frozen soils found throughout cold regions, contain vast quantities of carbon and ice. When permafrost thaws, carbon can be lost to the atmosphere, contributing to climate change. This means it is important to track permafrost thaw, which is often done using active layer thickness, or the depth of the seasonally thawed surface layer of soil. However, ice volume can be lost from thawing permafrost, causing the soil surface to drop. Conventional measurements do not account for this surface drop, and the rate of thaw could therefore be underestimated. We found that experimentally warmed soils dropped at a rate of 6 cm year−1, mostly due to loss of ice volume and also due to the loss of soil mass. When accounting for the change in soil surface height over time, the full depth of permafrost thaw was 49% greater. The increased depth of thaw resulted in more than twice as much carbon being thawed as was estimated with standard methods that did not account for subsidence. These findings suggest that permafrost is thawing more quickly than long‐term records indicate and that this could result in additional carbon release contributing to climate change. Key Points: Subsidence causes a shifting reference frame for measurements of permafrost thawThe rate of permafrost carbon thaw doubles when subsidence is accounted forSubsidence of up to 6 cm year−1 was observed in a permafrost warming experiment, due to both ice and soil loss [ABSTRACT FROM AUTHOR]

Published
2020
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124. Warming shortens flowering seasons of tundra plant communities

Author

Prevéy, Janet S., primary, Rixen, Christian, additional, Rüger, Nadja, additional, Høye, Toke T., additional, Bjorkman, Anne D., additional, Myers-Smith, Isla H., additional, Elmendorf, Sarah C., additional, Ashton, Isabel W., additional, Cannone, Nicoletta, additional, Chisholm, Chelsea L., additional, Clark, Karin, additional, Cooper, Elisabeth J., additional, Elberling, Bo, additional, Fosaa, Anna Maria, additional, Henry, Greg H. R., additional, Hollister, Robert D., additional, Jónsdóttir, Ingibjörg Svala, additional, Klanderud, Kari, additional, Kopp, Christopher W., additional, Lévesque, Esther, additional, Mauritz, Marguerite, additional, Molau, Ulf, additional, Natali, Susan M., additional, Oberbauer, Steven. F., additional, Panchen, Zoe A., additional, Post, Eric, additional, Rumpf, Sabine B., additional, Schmidt, Niels Martin, additional, Schuur, Edward, additional, Semenchuk, Philipp R., additional, Smith, Jane G., additional, Suding, Katharine N., additional, Totland, Ørjan, additional, Troxler, Tiffany, additional, Venn, Susanna, additional, Wahren, Carl-Henrik, additional, Welker, Jeffrey M., additional, and Wipf, Sonja, additional

Published
2018
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126. Reviews and syntheses: Changing ecosystem influences on soil thermal regimes in northern high-latitude permafrost regions

Author

Loranty, Michael M., primary, Abbott, Benjamin W., additional, Blok, Daan, additional, Douglas, Thomas A., additional, Epstein, Howard E., additional, Forbes, Bruce C., additional, Jones, Benjamin M., additional, Kholodov, Alexander L., additional, Kropp, Heather, additional, Malhotra, Avni, additional, Mamet, Steven D., additional, Myers-Smith, Isla H., additional, Natali, Susan M., additional, O'Donnell, Jonathan A., additional, Phoenix, Gareth K., additional, Rocha, Adrian V., additional, Sonnentag, Oliver, additional, Tape, Ken D., additional, and Walker, Donald A., additional

Published
2018
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127. Environmental and taxonomic controls of carbon and oxygen stable isotope composition in &lt;i&gt;Sphagnum&lt;/i&gt; across broad climatic and geographic ranges

Author

Granath, Gustaf, primary, Rydin, Håkan, additional, Baltzer, Jennifer L., additional, Bengtsson, Fia, additional, Boncek, Nicholas, additional, Bragazza, Luca, additional, Bu, Zhao-Jun, additional, Caporn, Simon J. M., additional, Dorrepaal, Ellen, additional, Galanina, Olga, additional, Gałka, Mariusz, additional, Ganeva, Anna, additional, Gillikin, David P., additional, Goia, Irina, additional, Goncharova, Nadezhda, additional, Hájek, Michal, additional, Haraguchi, Akira, additional, Harris, Lorna I., additional, Humphreys, Elyn, additional, Jiroušek, Martin, additional, Kajukało, Katarzyna, additional, Karofeld, Edgar, additional, Koronatova, Natalia G., additional, Kosykh, Natalia P., additional, Lamentowicz, Mariusz, additional, Lapshina, Elena, additional, Limpens, Juul, additional, Linkosalmi, Maiju, additional, Ma, Jin-Ze, additional, Mauritz, Marguerite, additional, Munir, Tariq M., additional, Natali, Susan M., additional, Natcheva, Rayna, additional, Noskova, Maria, additional, Payne, Richard J., additional, Pilkington, Kyle, additional, Robinson, Sean, additional, Robroek, Bjorn J. M., additional, Rochefort, Line, additional, Singer, David, additional, Stenøien, Hans K., additional, Tuittila, Eeva-Stiina, additional, Vellak, Kai, additional, Verheyden, Anouk, additional, Waddington, James Michael, additional, and Rice, Steven K., additional

Published
2018
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131. Greater temperature sensitivity of plant phenology at colder sites:Implications for convergence across northern latitudes

Author

Prevéy, Janet, Vellend, Mark, Rüger, Nadja, Hollister, Robert D., Bjorkman, Anne D., Myers-Smith, Isla H., Elmendorf, Sarah C., Clark, Karin, Cooper, Elisabeth J., Elberling, Bo, Fosaa, Anna Maria, Henry, Gregory H.R., Høye, Toke Thomas, Jónsdóttir, Ingibjörg S., Klanderud, Kari, Lévesque, Esther, Mauritz, Marguerite, Molau, Ulf, Natali, Susan M., Oberbauer, Steven F., Panchen, Zoe A., Post, Eric, Rumpf, Sabine B., Schmidt, Niels M, Schuur, Edward A.G., Semenchuk, Phillip R., Troxler, Tiffany, Welker, Jeffrey M., Rixen, Christian, Prevéy, Janet, Vellend, Mark, Rüger, Nadja, Hollister, Robert D., Bjorkman, Anne D., Myers-Smith, Isla H., Elmendorf, Sarah C., Clark, Karin, Cooper, Elisabeth J., Elberling, Bo, Fosaa, Anna Maria, Henry, Gregory H.R., Høye, Toke Thomas, Jónsdóttir, Ingibjörg S., Klanderud, Kari, Lévesque, Esther, Mauritz, Marguerite, Molau, Ulf, Natali, Susan M., Oberbauer, Steven F., Panchen, Zoe A., Post, Eric, Rumpf, Sabine B., Schmidt, Niels M, Schuur, Edward A.G., Semenchuk, Phillip R., Troxler, Tiffany, Welker, Jeffrey M., and Rixen, Christian

Abstract

Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high-latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering was more sensitive to a given increase in summer temperature at colder than warmer high-latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms.

Published
2017

133. Tundra is a consistent source of CO2 at a site with progressive permafrost thaw during 6 years of chamber and eddy covariance measurements

Author

Celis, Gerardo, primary, Mauritz, Marguerite, additional, Bracho, Rosvel, additional, Salmon, Verity G., additional, Webb, Elizabeth E., additional, Hutchings, Jack, additional, Natali, Susan M., additional, Schädel, Christina, additional, Crummer, Kathryn G., additional, and Schuur, Edward A. G., additional

Published
2017
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134. Supplementary material to "Variability in Above and Belowground Carbon Stocks in a Siberian Larch Watershed"

Author

Webb, Elizabeth E., primary, Heard, Kathryn, additional, Natali, Susan M., additional, Bunn, Andrew G., additional, Alexander, Heather D., additional, Berner, Logan T., additional, Kholodov, Alexander, additional, Loranty, Michael M., additional, Schade, John D., additional, Spektor, Valentin, additional, and Zimov, Nikita, additional

Published
2017
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136. Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes

Author

Prevéy, Janet, primary, Vellend, Mark, additional, Rüger, Nadja, additional, Hollister, Robert D., additional, Bjorkman, Anne D., additional, Myers‐Smith, Isla H., additional, Elmendorf, Sarah C., additional, Clark, Karin, additional, Cooper, Elisabeth J., additional, Elberling, Bo, additional, Fosaa, Anna M., additional, Henry, Gregory H. R., additional, Høye, Toke T., additional, Jónsdóttir, Ingibjörg S., additional, Klanderud, Kari, additional, Lévesque, Esther, additional, Mauritz, Marguerite, additional, Molau, Ulf, additional, Natali, Susan M., additional, Oberbauer, Steven F., additional, Panchen, Zoe A., additional, Post, Eric, additional, Rumpf, Sabine B., additional, Schmidt, Niels M., additional, Schuur, Edward A. G., additional, Semenchuk, Phillip R., additional, Troxler, Tiffany, additional, Welker, Jeffrey M., additional, and Rixen, Christian, additional

Published
2017
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137. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire : an expert assessment

Author

Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., Zimov, Sergei, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., and Zimov, Sergei

Abstract

As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced.

Published
2016
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138. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire

Author

University of Helsinki, Department of Environmental Sciences, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., Zimov, Sergei, University of Helsinki, Department of Environmental Sciences, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger K., Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., and Zimov, Sergei

Abstract

As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced.

Published
2016

139. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire: an expert assessment

Author

Abbott, Benjamin W, Jones, Jeremy B, Schuur, Edward A G, Chapin III, F Stuart, Bowden, William B, Bret-Harte, M Syndonia, Epstein, Howard E, Flannigan, Michael D, Harms, Tamara K, Hollingsworth, Teresa N, Mack, Michelle C, McGuire, A David, Natali, Susan M, Rocha, Adrian V, Tank, Suzanne E, Turetsky, Merritt R, Vonk, Jorien E, Wickland, Kimberly P, Aiken, George R, Alexander, Heather D, Amon, Rainer M W, Benscoter, Brian W, Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L, Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K, Chen, Jing M, Chen, Han Y H, Christensen, Torben R, Cooper, Lee W, Cornelissen, J Hans C, de Groot, William J, DeLuca, Thomas H, Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C, Forbes, Bruce C, French, Nancy H F, Gauthier, Sylvie, Girardin, Martin P, Goetz, Scott J, Goldammer, Johann G, Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E, Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E, Jandt, Randi, Johnstone, Jill F, Karlsson, Jan, Kasischke, Eric S, Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W, Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W, Mann, Paul J, Martikainen, Pertti J, McClelland, James W, Molau, Ulf, Oberbauer, Steven F, Olefeldt, David, Paré, David, Parisien, Marc-André, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S, Rastetter, Edward B, Raymond, Peter A, Raynolds, Martha K, Rein, Guillermo, Reynolds, James F, Robards, Martin, Rogers, Brendan M, Schädel, Christina, Schaefer, Kevin, Schmidt, Inger K, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G M, Starr, Gregory, Striegl, Robert G, Teisserenc, Roman, Tranvik, Lars J, Virtanen, Tarmo, Welker, Jeffrey M, Zimov, Sergei, Abbott, Benjamin W, Jones, Jeremy B, Schuur, Edward A G, Chapin III, F Stuart, Bowden, William B, Bret-Harte, M Syndonia, Epstein, Howard E, Flannigan, Michael D, Harms, Tamara K, Hollingsworth, Teresa N, Mack, Michelle C, McGuire, A David, Natali, Susan M, Rocha, Adrian V, Tank, Suzanne E, Turetsky, Merritt R, Vonk, Jorien E, Wickland, Kimberly P, Aiken, George R, Alexander, Heather D, Amon, Rainer M W, Benscoter, Brian W, Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L, Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K, Chen, Jing M, Chen, Han Y H, Christensen, Torben R, Cooper, Lee W, Cornelissen, J Hans C, de Groot, William J, DeLuca, Thomas H, Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C, Forbes, Bruce C, French, Nancy H F, Gauthier, Sylvie, Girardin, Martin P, Goetz, Scott J, Goldammer, Johann G, Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E, Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E, Jandt, Randi, Johnstone, Jill F, Karlsson, Jan, Kasischke, Eric S, Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W, Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W, Mann, Paul J, Martikainen, Pertti J, McClelland, James W, Molau, Ulf, Oberbauer, Steven F, Olefeldt, David, Paré, David, Parisien, Marc-André, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S, Rastetter, Edward B, Raymond, Peter A, Raynolds, Martha K, Rein, Guillermo, Reynolds, James F, Robards, Martin, Rogers, Brendan M, Schädel, Christina, Schaefer, Kevin, Schmidt, Inger K, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G M, Starr, Gregory, Striegl, Robert G, Teisserenc, Roman, Tranvik, Lars J, Virtanen, Tarmo, Welker, Jeffrey M, and Zimov, Sergei

Published
2016

140. Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire:an expert assessment

Author

Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger Kappel, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., Zimov, Sergei, Abbott, Benjamin W., Jones, Jeremy B., Schuur, Edward A. G., Chapin, F. Stuart, III, Bowden, William B., Bret-Harte, M. Syndonia, Epstein, Howard E., Flannigan, Michael D., Harms, Tamara K., Hollingsworth, Teresa N., Mack, Michelle C., McGuire, A. David, Natali, Susan M., Rocha, Adrian V., Tank, Suzanne E., Turetsky, Merritt R., Vonk, Jorien E., Wickland, Kimberly P., Aiken, George R., Alexander, Heather D., Amon, Rainer M. W., Benscoter, Brian W., Bergeron, Yves, Bishop, Kevin, Blarquez, Olivier, Bond-Lamberty, Ben, Breen, Amy L., Buffam, Ishi, Cai, Yihua, Carcaillet, Christopher, Carey, Sean K., Chen, Jing M., Chen, Han Y. H., Christensen, Torben R., Cooper, Lee W., Cornelissen, J. Hans C., de Groot, William J., DeLuca, Thomas H., Dorrepaal, Ellen, Fetcher, Ned, Finlay, Jacques C., Forbes, Bruce C., French, Nancy H. F., Gauthier, Sylvie, Girardin, Martin P., Goetz, Scott J., Goldammer, Johann G., Gough, Laura, Grogan, Paul, Guo, Laodong, Higuera, Philip E., Hinzman, Larry, Hu, Feng Sheng, Hugelius, Gustaf, Jafarov, Elchin E., Jandt, Randi, Johnstone, Jill F., Karlsson, Jan, Kasischke, Eric S., Kattner, Gerhard, Kelly, Ryan, Keuper, Frida, Kling, George W., Kortelainen, Pirkko, Kouki, Jari, Kuhry, Peter, Laudon, Hjalmar, Laurion, Isabelle, Macdonald, Robie W., Mann, Paul J., Martikainen, Pertti J., McClelland, James W., Molau, Ulf, Oberbauer, Steven F., Olefeldt, David, Pare, David, Parisien, Marc-Andre, Payette, Serge, Peng, Changhui, Pokrovsky, Oleg S., Rastetter, Edward B., Raymond, Peter A., Raynolds, Martha K., Rein, Guillermo, Reynolds, James F., Robards, Martin, Rogers, Brendan M., Schaedel, Christina, Schaefer, Kevin, Schmidt, Inger Kappel, Shvidenko, Anatoly, Sky, Jasper, Spencer, Robert G. M., Starr, Gregory, Striegl, Robert G., Teisserenc, Roman, Tranvik, Lars J., Virtanen, Tarmo, Welker, Jeffrey M., and Zimov, Sergei

Abstract

As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%?85% of permafrost carbon release can still be avoided if human emissions are actively reduced.

Published
2016

142. Potential carbon emissions dominated by carbon dioxide from thawed permafrost soils

Author

Schädel, Christina, primary, Bader, Martin K.-F., additional, Schuur, Edward A. G., additional, Biasi, Christina, additional, Bracho, Rosvel, additional, Čapek, Petr, additional, De Baets, Sarah, additional, Diáková, Kateřina, additional, Ernakovich, Jessica, additional, Estop-Aragones, Cristian, additional, Graham, David E., additional, Hartley, Iain P., additional, Iversen, Colleen M., additional, Kane, Evan, additional, Knoblauch, Christian, additional, Lupascu, Massimo, additional, Martikainen, Pertti J., additional, Natali, Susan M., additional, Norby, Richard J., additional, O’Donnell, Jonathan A., additional, Chowdhury, Taniya Roy, additional, Šantrůčková, Hana, additional, Shaver, Gaius, additional, Sloan, Victoria L., additional, Treat, Claire C., additional, Turetsky, Merritt R., additional, Waldrop, Mark P., additional, and Wickland, Kimberly P., additional

Published
2016
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146. Decadal warming causes a consistent and persistent shift from heterotrophic to autotrophic respiration in contrasting permafrost ecosystems

Author

Hicks Pries, Caitlin E., van Logtestijn, Richard S. P., Schuur, Edward A. G., Natali, Susan M., Cornelissen, Johannes H. C., Aerts, Rien, Dorrepaal, Ellen, Hicks Pries, Caitlin E., van Logtestijn, Richard S. P., Schuur, Edward A. G., Natali, Susan M., Cornelissen, Johannes H. C., Aerts, Rien, and Dorrepaal, Ellen

Abstract

Soil carbon in permafrost ecosystems has the potential to become a major positive feedback to climate change if permafrost thaw increases heterotrophic decomposition. However, warming can also stimulate autotrophic production leading to increased ecosystem carbon storage-a negative climate change feedback. Few studies partitioning ecosystem respiration examine decadal warming effects or compare responses among ecosystems. Here, we first examined how 11 years of warming during different seasons affected autotrophic and heterotrophic respiration in a bryophyte-dominated peatland in Abisko, Sweden. We used natural abundance radiocarbon to partition ecosystem respiration into autotrophic respiration, associated with production, and heterotrophic decomposition. Summertime warming decreased the age of carbon respired by the ecosystem due to increased proportional contributions from autotrophic and young soil respiration and decreased proportional contributions from old soil. Summertime warming's large effect was due to not only warmer air temperatures during the growing season, but also to warmer deep soils year-round. Second, we compared ecosystem respiration responses between two contrasting ecosystems, the Abisko peatland and a tussock-dominated tundra in Healy, Alaska. Each ecosystem had two different timescales of warming (<5years and over a decade). Despite the Abisko peatland having greater ecosystem respiration and larger contributions from heterotrophic respiration than the Healy tundra, both systems responded consistently to short- and long-term warming with increased respiration, increased autotrophic contributions to ecosystem respiration, and increased ratios of autotrophic to heterotrophic respiration. We did not detect an increase in old soil carbon losses with warming at either site. If increased autotrophic respiration is balanced by increased primary production, as is the case in the Healy tundra, warming will not cause these ecosystems to become grow

Published
2015
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147. Large loss of CO2in winter observed across the northern permafrost region

Author

Natali, Susan M., Watts, Jennifer D., Rogers, Brendan M., Potter, Stefano, Ludwig, Sarah M., Selbmann, Anne-Katrin, Sullivan, Patrick F., Abbott, Benjamin W., Arndt, Kyle A., Birch, Leah, Bjo¨rkman, Mats P., Bloom, A. Anthony, Celis, Gerardo, Christensen, Torben R., Christiansen, Casper T., Commane, Roisin, Cooper, Elisabeth J., Crill, Patrick, Czimczik, Claudia, Davydov, Sergey, Du, Jinyang, Egan, Jocelyn E., Elberling, Bo, Euskirchen, Eugenie S., Friborg, Thomas, Genet, Hélène, Göckede, Mathias, Goodrich, Jordan P., Grogan, Paul, Helbig, Manuel, Jafarov, Elchin E., Jastrow, Julie D., Kalhori, Aram A. M., Kim, Yongwon, Kimball, John S., Kutzbach, Lars, Lara, Mark J., Larsen, Klaus S., Lee, Bang-Yong, Liu, Zhihua, Loranty, Michael M., Lund, Magnus, Lupascu, Massimo, Madani, Nima, Malhotra, Avni, Matamala, Roser, McFarland, Jack, McGuire, A. David, Michelsen, Anders, Minions, Christina, Oechel, Walter C., Olefeldt, David, Parmentier, Frans-Jan W., Pirk, Norbert, Poulter, Ben, Quinton, William, Rezanezhad, Fereidoun, Risk, David, Sachs, Torsten, Schaefer, Kevin, Schmidt, Niels M., Schuur, Edward A. G., Semenchuk, Philipp R., Shaver, Gaius, Sonnentag, Oliver, Starr, Gregory, Treat, Claire C., Waldrop, Mark P., Wang, Yihui, Welker, Jeffrey, Wille, Christian, Xu, Xiaofeng, Zhang, Zhen, Zhuang, Qianlai, and Zona, Donatella

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 CO2released 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 CO2flux 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 CO2emissions 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 CO2emissions from northern terrestrial regions and indicate that enhanced soil CO2loss due to winter warming may offset growing season carbon uptake under future climatic conditions.

Published
2019
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150. A pan‐Arctic synthesis of CH 4 and CO 2 production from anoxic soil incubations

Author

Treat, Claire C., primary, Natali, Susan M., additional, Ernakovich, Jessica, additional, Iversen, Colleen M., additional, Lupascu, Massimo, additional, McGuire, Anthony David, additional, Norby, Richard J., additional, Roy Chowdhury, Taniya, additional, Richter, Andreas, additional, Šantrůčková, Hana, additional, Schädel, Christina, additional, Schuur, Edward A. G., additional, Sloan, Victoria L., additional, Turetsky, Merritt R., additional, and Waldrop, Mark P., additional

Published
2015
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