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Articles | Volume 10, issue 12
Biogeosciences, 10, 8185–8200, 2013
https://doi.org/10.5194/bg-10-8185-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Special issue: Interactions between climate change and the Cryosphere: SVALI,...
Biogeosciences, 10, 8185–8200, 2013
https://doi.org/10.5194/bg-10-8185-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article 11 Dec 2013
Research article | 11 Dec 2013
Testing the applicability of neural networks as a gap-filling method using CH4 flux data from high latitude wetlands
S. Dengel et al.
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Pertti Hari, Steffen Noe, Sigrid Dengel, Jan Elbers, Bert Gielen, Veli-Matti Kerminen, Bart Kruijt, Liisa Kulmala, Anders Lindroth, Ivan Mammarella, Tuukka Petäjä, Guy Schurgers, Anni Vanhatalo, Markku Kulmala, and Jaana Bäck
Atmos. Chem. Phys., 18, 13321–13328, https://doi.org/10.5194/acp-18-13321-2018, https://doi.org/10.5194/acp-18-13321-2018, 2018
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The development of eddy-covariance measurements of ecosystem CO2 fluxes began a new era in the field studies of photosynthesis. The interpretation of the very variable CO2 fluxes in evergreen forests has been problematic especially in seasonal transition times. We apply two theoretical needle-level equations and show they can predict photosynthetic CO2 flux between the atmosphere and Scots pine forests. This has strong implications for the interpretation of the global change and boreal forests.
Mathilde Jammet, Sigrid Dengel, Ernesto Kettner, Frans-Jan W. Parmentier, Martin Wik, Patrick Crill, and Thomas Friborg
Biogeosciences, 14, 5189–5216, https://doi.org/10.5194/bg-14-5189-2017, https://doi.org/10.5194/bg-14-5189-2017, 2017
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The quantitative importance of northern lakes in terrestrial carbon budgets is uncertain, as year-round observations of carbon fluxes are rare. We measured CH4 and CO2 fluxes from a subarctic lake and nearby fen during 2.5 years with one eddy covariance system. We identified drivers of seasonal variability in lake fluxes and show the importance of winter and spring for annual carbon exchange in both ecosystems. The lake as a source of atmospheric carbon partially compensates the fen carbon sink.
Pavel Alekseychik, Ivan Mammarella, Dmitry Karpov, Sigrid Dengel, Irina Terentieva, Alexander Sabrekov, Mikhail Glagolev, and Elena Lapshina
Atmos. Chem. Phys., 17, 9333–9345, https://doi.org/10.5194/acp-17-9333-2017, https://doi.org/10.5194/acp-17-9333-2017, 2017
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West Siberian peatlands occupy a large fraction of land area in the region, and yet little is known about their interaction with the atmosphere. We took the first measurements of CO2 and energy surface balances over a typical bog of West Siberian middle taiga, in the vicinity of the Mukhrino field station (Khanty–Mansiysk). The May–August study in a wet year (2015) revealed a relatively large photosynthetic sink of CO2 that was close to the high end of estimates at bog sites elsewhere.
S. Dengel, J. Grace, and A. MacArthur
Biogeosciences, 12, 4195–4207, https://doi.org/10.5194/bg-12-4195-2015, https://doi.org/10.5194/bg-12-4195-2015, 2015
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We tested the hypothesis that diffuse radiation from cloudy and overcast skies penetrates the canopy more effectively than direct radiation from clear skies. We compared the flux density and spectral properties of direct and diffuse radiation above, within and below a forest stand under sunny, cloudy and overcast conditions in a thinned Sitka spruce forest. We recorded vertical (1m resolution) and horizontal (2.5m resolution) profiles of radiation penetration at 1nm resolution.
Leah Birch, Christopher R. Schwalm, Sue Natali, Danica Lombardozzi, Gretchen Keppel-Aleks, Jennifer Watts, Xin Lin, Donatella Zona, Walter Oechel, Torsten Sachs, Thomas Andrew Black, and Brendan M. Rogers
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2020-365, https://doi.org/10.5194/gmd-2020-365, 2020
Preprint under review for GMD
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The high latitude landscape or Arctic-Boreal Zone has been warming rapidly, impacting the carbon balance, both regionally and globally. Given the possible global effects of climate change, it is important to have accurate climate model simulations. We assess the simulation of the Arctic-Boreal carbon cycle in the Community Land Model (CLM 5.0). We find biases in both the timing and magnitude photosynthesis. We then use observational data to improve the simulation of the carbon cycle.
Hui Zhang, Eeva-Stiina Tuittila, Aino Korrensalo, Aleksi Räsänen, Tarmo Virtanen, Mika Aurela, Timo Penttilä, Tuomas Laurila, Stephanie Gerin, Viivi Lindholm, and Annalea Lohila
Biogeosciences, 17, 6247–6270, https://doi.org/10.5194/bg-17-6247-2020, https://doi.org/10.5194/bg-17-6247-2020, 2020
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We studied the impact of a stream on peatland microhabitats and CH4 emissions in a northern boreal fen. We found that there were higher water levels, lower peat temperatures, and greater oxygen concentrations close to the stream; these supported the highest biomass production but resulted in the lowest CH4 emissions. Further from the stream, the conditions were drier and CH4 emissions were also low. CH4 emissions were highest at an intermediate distance from the stream.
Yonghong Yi, John S. Kimball, Jennifer D. Watts, Susan M. Natali, Donatella Zona, Junjie Liu, Masahito Ueyama, Hideki Kobayashi, Walter Oechel, and Charles E. Miller
Biogeosciences, 17, 5861–5882, https://doi.org/10.5194/bg-17-5861-2020, https://doi.org/10.5194/bg-17-5861-2020, 2020
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We developed a 1 km satellite-data-driven permafrost carbon model to evaluate soil respiration sensitivity to recent snow cover changes in Alaska. Results show earlier snowmelt enhances growing-season soil respiration and reduces annual carbon uptake, while early cold-season soil respiration is linked to the number of snow-free days after the land surface freezes. Our results also show nonnegligible influences of subgrid variability in surface conditions on model-simulated CO2 seasonal cycles.
Felix Nieberding, Christian Wille, Gerardo Fratini, Magnus O. Asmussen, Yuyang Wang, Yaoming Ma, and Torsten Sachs
Earth Syst. Sci. Data, 12, 2705–2724, https://doi.org/10.5194/essd-12-2705-2020, https://doi.org/10.5194/essd-12-2705-2020, 2020
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We present the first long-term eddy covariance CO2 and H2O flux measurements from the large but underrepresented alpine steppe ecosystem on the central Tibetan Plateau. We applied careful corrections and rigorous quality filtering and analyzed the turbulent flow regime to provide meaningful fluxes. This comprehensive data set allows potential users to put the gas flux dynamics into context with ecosystem properties and potential flux drivers and allows for comparisons with other data sets.
Lauri Heiskanen, Juha-Pekka Tuovinen, Aleksi Räsänen, Tarmo Virtanen, Sari Juutinen, Annalea Lohila, Timo Penttilä, Maiju Linkosalmi, Juha Mikola, Tuomas Laurila, and Mika Aurela
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-370, https://doi.org/10.5194/bg-2020-370, 2020
Revised manuscript accepted for BG
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We studied ecosystem and plant community level carbon (C) exchange between subarctic mire and the atmosphere during 2017–2018. We found strong spatial variation in CO2 and CH4 dynamics between the main plant communities. The earlier onset of growing season in 2018 strengthened the CO2 sink of the ecosystem, but this gain was counterbalanced by a later drought period. Variation in water table level, soil temperature and vegetation explained most of the variation in the ecosystem level C exchange.
Tuukka Petäjä, Ella-Maria Duplissy, Ksenia Tabakova, Julia Schmale, Barbara Altstädter, Gerard Ancellet, Mikhail Arshinov, Yurii Balin, Urs Baltensperger, Jens Bange, Alison Beamish, Boris Belan, Antoine Berchet, Rossana Bossi, Warren R. L. Cairns, Ralf Ebinghaus, Imad El Haddad, Beatriz Ferreira-Araujo, Anna Franck, Lin Huang, Antti Hyvärinen, Angelika Humbert, Athina-Cerise Kalogridis, Pavel Konstantinov, Astrid Lampert, Matthew MacLeod, Olivier Magand, Alexander Mahura, Louis Marelle, Vladimir Masloboev, Dmitri Moisseev, Vaios Moschos, Niklas Neckel, Tatsuo Onishi, Stefan Osterwalder, Aino Ovaska, Pauli Paasonen, Mikhail Panchenko, Fidel Pankratov, Jakob B. Pernov, Andreas Platis, Olga Popovicheva, Jean-Christophe Raut, Aurélie Riandet, Torsten Sachs, Rosamaria Salvatori, Roberto Salzano, Ludwig Schröder, Martin Schön, Vladimir Shevchenko, Henrik Skov, Jeroen E. Sonke, Andrea Spolaor, Vasileios K. Stathopoulos, Mikko Strahlendorff, Jennie L. Thomas, Vito Vitale, Sterios Vratolis, Carlo Barbante, Sabine Chabrillat, Aurélien Dommergue, Konstantinos Eleftheriadis, Jyri Heilimo, Kathy S. Law, Andreas Massling, Steffen M. Noe, Jean-Daniel Paris, André S. H. Prévôt, Ilona Riipinen, Birgit Wehner, Zhiyong Xie, and Hanna K. Lappalainen
Atmos. Chem. Phys., 20, 8551–8592, https://doi.org/10.5194/acp-20-8551-2020, https://doi.org/10.5194/acp-20-8551-2020, 2020
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The role of polar regions is increasing in terms of megatrends such as globalization, new transport routes, demography, and the use of natural resources with consequent effects on regional and transported pollutant concentrations. Here we summarize initial results from our integrative project exploring the Arctic environment and pollution to deliver data products, metrics, and indicators for stakeholders.
Heidi Hellén, Simon Schallhart, Arnaud P. Praplan, Toni Tykkä, Mika Aurela, Annalea Lohila, and Hannele Hakola
Atmos. Chem. Phys., 20, 7021–7034, https://doi.org/10.5194/acp-20-7021-2020, https://doi.org/10.5194/acp-20-7021-2020, 2020
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We studied biogenic volatile organic compound emissions and their ambient concentrations in a sub-Arctic wetland. Although isoprene was the main terpenoid emitted, sesquiterpene emissions were also highly significant, especially in early summer. Sesquiterpenes have much higher potential to form secondary organic aerosol than isoprenes. High sesquiterpene emissions during early summer suggested that melting snow and thawing soil could be an important source of these compounds.
Chris R. Flechard, Andreas Ibrom, Ute M. Skiba, Wim de Vries, Marcel van Oijen, David R. Cameron, Nancy B. Dise, Janne F. J. Korhonen, Nina Buchmann, Arnaud Legout, David Simpson, Maria J. Sanz, Marc Aubinet, Denis Loustau, Leonardo Montagnani, Johan Neirynck, Ivan A. Janssens, Mari Pihlatie, Ralf Kiese, Jan Siemens, André-Jean Francez, Jürgen Augustin, Andrej Varlagin, Janusz Olejnik, Radosław Juszczak, Mika Aurela, Daniel Berveiller, Bogdan H. Chojnicki, Ulrich Dämmgen, Nicolas Delpierre, Vesna Djuricic, Julia Drewer, Eric Dufrêne, Werner Eugster, Yannick Fauvel, David Fowler, Arnoud Frumau, André Granier, Patrick Gross, Yannick Hamon, Carole Helfter, Arjan Hensen, László Horváth, Barbara Kitzler, Bart Kruijt, Werner L. Kutsch, Raquel Lobo-do-Vale, Annalea Lohila, Bernard Longdoz, Michal V. Marek, Giorgio Matteucci, Marta Mitosinkova, Virginie Moreaux, Albrecht Neftel, Jean-Marc Ourcival, Kim Pilegaard, Gabriel Pita, Francisco Sanz, Jan K. Schjoerring, Maria-Teresa Sebastià, Y. Sim Tang, Hilde Uggerud, Marek Urbaniak, Netty van Dijk, Timo Vesala, Sonja Vidic, Caroline Vincke, Tamás Weidinger, Sophie Zechmeister-Boltenstern, Klaus Butterbach-Bahl, Eiko Nemitz, and Mark A. Sutton
Biogeosciences, 17, 1583–1620, https://doi.org/10.5194/bg-17-1583-2020, https://doi.org/10.5194/bg-17-1583-2020, 2020
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Experimental evidence from a network of 40 monitoring sites in Europe suggests that atmospheric nitrogen deposition to forests and other semi-natural vegetation impacts the carbon sequestration rates in ecosystems, as well as the net greenhouse gas balance including other greenhouse gases such as nitrous oxide and methane. Excess nitrogen deposition in polluted areas also leads to other environmental impacts such as nitrogen leaching to groundwater and other pollutant gaseous emissions.
Chris R. Flechard, Marcel van Oijen, David R. Cameron, Wim de Vries, Andreas Ibrom, Nina Buchmann, Nancy B. Dise, Ivan A. Janssens, Johan Neirynck, Leonardo Montagnani, Andrej Varlagin, Denis Loustau, Arnaud Legout, Klaudia Ziemblińska, Marc Aubinet, Mika Aurela, Bogdan H. Chojnicki, Julia Drewer, Werner Eugster, André-Jean Francez, Radosław Juszczak, Barbara Kitzler, Werner L. Kutsch, Annalea Lohila, Bernard Longdoz, Giorgio Matteucci, Virginie Moreaux, Albrecht Neftel, Janusz Olejnik, Maria J. Sanz, Jan Siemens, Timo Vesala, Caroline Vincke, Eiko Nemitz, Sophie Zechmeister-Boltenstern, Klaus Butterbach-Bahl, Ute M. Skiba, and Mark A. Sutton
Biogeosciences, 17, 1621–1654, https://doi.org/10.5194/bg-17-1621-2020, https://doi.org/10.5194/bg-17-1621-2020, 2020
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Nitrogen deposition from the atmosphere to unfertilized terrestrial vegetation such as forests can increase carbon dioxide uptake and favour carbon sequestration by ecosystems. However the data from observational networks are difficult to interpret in terms of a carbon-to-nitrogen response, because there are a number of other confounding factors, such as climate, soil physical properties and fertility, and forest age. We propose a model-based method to untangle the different influences.
Matti Räsänen, Mika Aurela, Ville Vakkari, Johan P. Beukes, Juha-Pekka Tuovinen, Pieter G. Van Zyl, Miroslav Josipovic, Stefan J. Siebert, Tuomas Laurila, Markku Kulmala, Lauri Laakso, Janne Rinne, Ram Oren, and Gabriel Katul
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2019-651, https://doi.org/10.5194/hess-2019-651, 2020
Revised manuscript not accepted
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The annual ET is approximately equal to precipitation during six measured years for grazed savanna grassland. The computed annual transpiration was highly constrained when rainfall was near or above the long-term mean but was reduced during severe drought year. The developed methodologies can be used in a wide range of arid and semi-arid ecosystems.
Jarmo Mäkelä, Jürgen Knauer, Mika Aurela, Andrew Black, Martin Heimann, Hideki Kobayashi, Annalea Lohila, Ivan Mammarella, Hank Margolis, Tiina Markkanen, Jouni Susiluoto, Tea Thum, Toni Viskari, Sönke Zaehle, and Tuula Aalto
Geosci. Model Dev., 12, 4075–4098, https://doi.org/10.5194/gmd-12-4075-2019, https://doi.org/10.5194/gmd-12-4075-2019, 2019
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We assess the differences of six stomatal conductance formulations, embedded into a land–vegetation model JSBACH, on 10 boreal coniferous evergreen forest sites. We calibrate the model parameters using all six functions in a multi-year experiment, as well as for a separate drought event at one of the sites, using the adaptive population importance sampler. The analysis reveals weaknesses in the stomatal conductance formulation-dependent model behaviour that we are able to partially amend.
Olli Peltola, Timo Vesala, Yao Gao, Olle Räty, Pavel Alekseychik, Mika Aurela, Bogdan Chojnicki, Ankur R. Desai, Albertus J. Dolman, Eugenie S. Euskirchen, Thomas Friborg, Mathias Göckede, Manuel Helbig, Elyn Humphreys, Robert B. Jackson, Georg Jocher, Fortunat Joos, Janina Klatt, Sara H. Knox, Natalia Kowalska, Lars Kutzbach, Sebastian Lienert, Annalea Lohila, Ivan Mammarella, Daniel F. Nadeau, Mats B. Nilsson, Walter C. Oechel, Matthias Peichl, Thomas Pypker, William Quinton, Janne Rinne, Torsten Sachs, Mateusz Samson, Hans Peter Schmid, Oliver Sonnentag, Christian Wille, Donatella Zona, and Tuula Aalto
Earth Syst. Sci. Data, 11, 1263–1289, https://doi.org/10.5194/essd-11-1263-2019, https://doi.org/10.5194/essd-11-1263-2019, 2019
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Here we develop a monthly gridded dataset of northern (> 45 N) wetland methane (CH4) emissions. The data product is derived using a random forest machine-learning technique and eddy covariance CH4 fluxes from 25 wetland sites. Annual CH4 emissions from these wetlands calculated from the derived data product are comparable to prior studies focusing on these areas. This product is an independent estimate of northern wetland CH4 emissions and hence could be used, e.g. for process model evaluation.
Andrew M. Cunliffe, George Tanski, Boris Radosavljevic, William F. Palmer, Torsten Sachs, Hugues Lantuit, Jeffrey T. Kerby, and Isla H. Myers-Smith
The Cryosphere, 13, 1513–1528, https://doi.org/10.5194/tc-13-1513-2019, https://doi.org/10.5194/tc-13-1513-2019, 2019
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Episodic changes of permafrost coastlines are poorly understood in the Arctic. By using drones, satellite images, and historic photos we surveyed a permafrost coastline on Qikiqtaruk – Herschel Island. We observed short-term coastline retreat of 14.5 m per year (2016–2017), exceeding long-term average rates of 2.2 m per year (1952–2017). Our study highlights the value of these tools to assess understudied episodic changes of eroding permafrost coastlines in the context of a warming Arctic.
Franziska Koebsch, Matthias Winkel, Susanne Liebner, Bo Liu, Julia Westphal, Iris Schmiedinger, Alejandro Spitzy, Matthias Gehre, Gerald Jurasinski, Stefan Köhler, Viktoria Unger, Marian Koch, Torsten Sachs, and Michael E. Böttcher
Biogeosciences, 16, 1937–1953, https://doi.org/10.5194/bg-16-1937-2019, https://doi.org/10.5194/bg-16-1937-2019, 2019
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In natural coastal wetlands, high supplies of marine sulfate suppress methane production. We found these natural methane suppression mechanisms to be suspended by humane interference in a brackish wetland. Here, diking and freshwater rewetting had caused an efficient depletion of the sulfate reservoir and opened up favorable conditions for an intensive methane production. Our results demonstrate how human disturbance can turn coastal wetlands into distinct sources of the greenhouse gas methane.
David Holl, Christian Wille, Torsten Sachs, Peter Schreiber, Benjamin R. K. Runkle, Lutz Beckebanze, Moritz Langer, Julia Boike, Eva-Maria Pfeiffer, Irina Fedorova, Dimitry Y. Bolshianov, Mikhail N. Grigoriev, and Lars Kutzbach
Earth Syst. Sci. Data, 11, 221–240, https://doi.org/10.5194/essd-11-221-2019, https://doi.org/10.5194/essd-11-221-2019, 2019
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We present a multi-annual time series of land–atmosphere carbon dioxide fluxes measured in situ with the eddy covariance technique in the Siberian Arctic. In arctic permafrost regions, climate–carbon feedbacks are amplified. Therefore, increased efforts to better represent these regions in global climate models have been made in recent years. Up to now, the available database of in situ measurements from the Arctic was biased towards Alaska and records from the Eurasian Arctic were scarce.
Juha-Pekka Tuovinen, Mika Aurela, Juha Hatakka, Aleksi Räsänen, Tarmo Virtanen, Juha Mikola, Viktor Ivakhov, Vladimir Kondratyev, and Tuomas Laurila
Biogeosciences, 16, 255–274, https://doi.org/10.5194/bg-16-255-2019, https://doi.org/10.5194/bg-16-255-2019, 2019
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We analysed ecosystem-scale measurements of methane exchange between Arctic tundra and the atmosphere, taking into account the large variations in vegetation and soil properties. The measurements are spatial averages, but using meteorological and statistical modelling techniques we could estimate methane emissions for different land cover types and quantify how well the measurements correspond to the spatial variability. This provides a more accurate estimate of the regional methane emission.
Xi Wen, Viktoria Unger, Gerald Jurasinski, Franziska Koebsch, Fabian Horn, Gregor Rehder, Torsten Sachs, Dominik Zak, Gunnar Lischeid, Klaus-Holger Knorr, Michael E. Böttcher, Matthias Winkel, Paul L. E. Bodelier, and Susanne Liebner
Biogeosciences, 15, 6519–6536, https://doi.org/10.5194/bg-15-6519-2018, https://doi.org/10.5194/bg-15-6519-2018, 2018
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Rewetting drained peatlands may lead to prolonged emission of the greenhouse gas methane, but the underlying factors are not well described. In this study, we found two rewetted fens with known high methane fluxes had a high ratio of microbial methane producers to methane consumers and a low abundance of methane consumers compared to pristine wetlands. We therefore suggest abundances of methane-cycling microbes as potential indicators for prolonged high methane emissions in rewetted peatlands.
Sophia Walther, Luis Guanter, Birgit Heim, Martin Jung, Gregory Duveiller, Aleksandra Wolanin, and Torsten Sachs
Biogeosciences, 15, 6221–6256, https://doi.org/10.5194/bg-15-6221-2018, https://doi.org/10.5194/bg-15-6221-2018, 2018
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We explored the timing of the peak of the short annual growing season in tundra ecosystems as indicated by an extensive suite of satellite indicators of vegetation productivity. Delayed peak greenness compared to peak photosynthesis is consistently found across years and land-cover classes. Plants also experience growth after optimal conditions for assimilation regarding light and temperature have passed. Our results have implications for the modelling of the circumpolar carbon balance.
Pertti Hari, Steffen Noe, Sigrid Dengel, Jan Elbers, Bert Gielen, Veli-Matti Kerminen, Bart Kruijt, Liisa Kulmala, Anders Lindroth, Ivan Mammarella, Tuukka Petäjä, Guy Schurgers, Anni Vanhatalo, Markku Kulmala, and Jaana Bäck
Atmos. Chem. Phys., 18, 13321–13328, https://doi.org/10.5194/acp-18-13321-2018, https://doi.org/10.5194/acp-18-13321-2018, 2018
Short summary
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The development of eddy-covariance measurements of ecosystem CO2 fluxes began a new era in the field studies of photosynthesis. The interpretation of the very variable CO2 fluxes in evergreen forests has been problematic especially in seasonal transition times. We apply two theoretical needle-level equations and show they can predict photosynthetic CO2 flux between the atmosphere and Scots pine forests. This has strong implications for the interpretation of the global change and boreal forests.
Jörg Hartmann, Martin Gehrmann, Katrin Kohnert, Stefan Metzger, and Torsten Sachs
Atmos. Meas. Tech., 11, 4567–4581, https://doi.org/10.5194/amt-11-4567-2018, https://doi.org/10.5194/amt-11-4567-2018, 2018
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We present new in-flight calibration procedures for airborne turbulence measurements that exploit suitable regular flight legs without the need for dedicated calibration patterns. Furthermore we estimate the accuracy of the airborne wind measurement and of the turbulent fluxes of the traces gases methane and carbon dioxide.
Andrei Serafimovich, Stefan Metzger, Jörg Hartmann, Katrin Kohnert, Donatella Zona, and Torsten Sachs
Atmos. Chem. Phys., 18, 10007–10023, https://doi.org/10.5194/acp-18-10007-2018, https://doi.org/10.5194/acp-18-10007-2018, 2018
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In order to support the evaluation of coupled atmospheric–land-surface models we investigated spatial patterns of energy fluxes in relation to land-surface properties and upscaled airborne flux measurements to high resolution flux maps. A machine learning technique allows us to estimate environmental response functions between spatially and temporally resolved flux observations and corresponding biophysical and meteorological drivers.
Kari Minkkinen, Paavo Ojanen, Timo Penttilä, Mika Aurela, Tuomas Laurila, Juha-Pekka Tuovinen, and Annalea Lohila
Biogeosciences, 15, 3603–3624, https://doi.org/10.5194/bg-15-3603-2018, https://doi.org/10.5194/bg-15-3603-2018, 2018
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Drainage often turns peatlands into C sources. We measured C dynamics of a drained forested boreal peatland over 4 years, including one with a drought during growing season. The drained peatland ecosystem was a strong sink of C in all studied years. Also, the peat soil sequestered C. A drought period in one summer significantly decreased C sequestration through decreased gross primary production, but since the drought also decreased ecosystem respiration, the site remained a C sink.
Juha Mikola, Tarmo Virtanen, Maiju Linkosalmi, Emmi Vähä, Johanna Nyman, Olga Postanogova, Aleksi Räsänen, D. Johan Kotze, Tuomas Laurila, Sari Juutinen, Vladimir Kondratyev, and Mika Aurela
Biogeosciences, 15, 2781–2801, https://doi.org/10.5194/bg-15-2781-2018, https://doi.org/10.5194/bg-15-2781-2018, 2018
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To support C exchange measurements, we examined plant and soil attributes in Siberian Arctic tundra. Our results illustrate a typical tundra ecosystem with great spatial variation. Mosses dominate plant biomass and control many soil attributes such as temperature, but variation in moss biomass is difficult to capture by remote sensing. This indicates challenges in spatial extrapolation of some of those plant and soil attributes that are relevant for regional ecosystem and global climate models.
Astrid Lampert, Jörg Hartmann, Falk Pätzold, Lennart Lobitz, Peter Hecker, Katrin Kohnert, Eric Larmanou, Andrei Serafimovich, and Torsten Sachs
Atmos. Meas. Tech., 11, 2523–2536, https://doi.org/10.5194/amt-11-2523-2018, https://doi.org/10.5194/amt-11-2523-2018, 2018
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We compared two different fast-response humidity sensors simultaneously on different airborne platforms. One is a particular, well-establed Lyman-alpha hygrometer that has been used for decades as the standard for fast airborne humidity measurements. However, it is not available any more. The other one is a hygrometer based on the absorption of infrared radiation, from LI-COR. For an environment of low vibrations, the LI-COR sensor is suitable for fast airborne water vapour measurements.
Jannis von Buttlar, Jakob Zscheischler, Anja Rammig, Sebastian Sippel, Markus Reichstein, Alexander Knohl, Martin Jung, Olaf Menzer, M. Altaf Arain, Nina Buchmann, Alessandro Cescatti, Damiano Gianelle, Gerard Kiely, Beverly E. Law, Vincenzo Magliulo, Hank Margolis, Harry McCaughey, Lutz Merbold, Mirco Migliavacca, Leonardo Montagnani, Walter Oechel, Marian Pavelka, Matthias Peichl, Serge Rambal, Antonio Raschi, Russell L. Scott, Francesco P. Vaccari, Eva van Gorsel, Andrej Varlagin, Georg Wohlfahrt, and Miguel D. Mahecha
Biogeosciences, 15, 1293–1318, https://doi.org/10.5194/bg-15-1293-2018, https://doi.org/10.5194/bg-15-1293-2018, 2018
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Our work systematically quantifies extreme heat and drought event impacts on gross primary productivity (GPP) and ecosystem respiration globally across a wide range of ecosystems. We show that heat extremes typically increased mainly respiration whereas drought decreased both fluxes. Combined heat and drought extremes had opposing effects offsetting each other for respiration, but there were also strong reductions in GPP and hence the strongest reductions in the ecosystems carbon sink capacity.
Chunjing Qiu, Dan Zhu, Philippe Ciais, Bertrand Guenet, Gerhard Krinner, Shushi Peng, Mika Aurela, Christian Bernhofer, Christian Brümmer, Syndonia Bret-Harte, Housen Chu, Jiquan Chen, Ankur R. Desai, Jiří Dušek, Eugénie S. Euskirchen, Krzysztof Fortuniak, Lawrence B. Flanagan, Thomas Friborg, Mateusz Grygoruk, Sébastien Gogo, Thomas Grünwald, Birger U. Hansen, David Holl, Elyn Humphreys, Miriam Hurkuck, Gerard Kiely, Janina Klatt, Lars Kutzbach, Chloé Largeron, Fatima Laggoun-Défarge, Magnus Lund, Peter M. Lafleur, Xuefei Li, Ivan Mammarella, Lutz Merbold, Mats B. Nilsson, Janusz Olejnik, Mikaell Ottosson-Löfvenius, Walter Oechel, Frans-Jan W. Parmentier, Matthias Peichl, Norbert Pirk, Olli Peltola, Włodzimierz Pawlak, Daniel Rasse, Janne Rinne, Gaius Shaver, Hans Peter Schmid, Matteo Sottocornola, Rainer Steinbrecher, Torsten Sachs, Marek Urbaniak, Donatella Zona, and Klaudia Ziemblinska
Geosci. Model Dev., 11, 497–519, https://doi.org/10.5194/gmd-11-497-2018, https://doi.org/10.5194/gmd-11-497-2018, 2018
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Northern peatlands store large amount of soil carbon and are vulnerable to climate change. We implemented peatland hydrological and carbon accumulation processes into the ORCHIDEE land surface model. The model was evaluated against EC measurements from 30 northern peatland sites. The model generally well reproduced the spatial gradient and temporal variations in GPP and NEE at these sites. Water table depth was not well predicted but had only small influence on simulated NEE.
Mikko Peltoniemi, Mika Aurela, Kristin Böttcher, Pasi Kolari, John Loehr, Jouni Karhu, Maiju Linkosalmi, Cemal Melih Tanis, Juha-Pekka Tuovinen, and Ali Nadir Arslan
Earth Syst. Sci. Data, 10, 173–184, https://doi.org/10.5194/essd-10-173-2018, https://doi.org/10.5194/essd-10-173-2018, 2018
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Monitoring ecosystems using low-cost time lapse cameras has gained wide interest among researchers worldwide. Quantitative information stored in image pixels can be analysed automatically to track time-dependent phenomena, e.g. seasonal course of leaves in the canopies or snow on ground. As such, cameras can provide valuable ground references to earth observation. Here we document the ecosystem camera network we established to Finland and publish time series of images recorded between 2014–2016.
Yonghong Yi, John S. Kimball, Richard H. Chen, Mahta Moghaddam, Rolf H. Reichle, Umakant Mishra, Donatella Zona, and Walter C. Oechel
The Cryosphere, 12, 145–161, https://doi.org/10.5194/tc-12-145-2018, https://doi.org/10.5194/tc-12-145-2018, 2018
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An important feature of the Arctic is large spatial heterogeneity in active layer conditions. We developed a modeling framework integrating airborne longwave radar and satellite data to investigate active layer thickness (ALT) sensitivity to landscape heterogeneity in Alaska. We find uncertainty in spatial and vertical distribution of soil organic carbon is the largest factor affecting ALT accuracy. Advances in remote sensing of soil conditions will enable more accurate ALT predictions.
Maarit Raivonen, Sampo Smolander, Leif Backman, Jouni Susiluoto, Tuula Aalto, Tiina Markkanen, Jarmo Mäkelä, Janne Rinne, Olli Peltola, Mika Aurela, Annalea Lohila, Marin Tomasic, Xuefei Li, Tuula Larmola, Sari Juutinen, Eeva-Stiina Tuittila, Martin Heimann, Sanna Sevanto, Thomas Kleinen, Victor Brovkin, and Timo Vesala
Geosci. Model Dev., 10, 4665–4691, https://doi.org/10.5194/gmd-10-4665-2017, https://doi.org/10.5194/gmd-10-4665-2017, 2017
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Wetlands are one of the most significant natural sources of the strong greenhouse gas methane. We developed a model that can be used within a larger wetland carbon model to simulate the methane emissions. In this study, we present the model and results of its testing. We found that the model works well with different settings and that the results depend primarily on the rate of input anoxic soil respiration and also on factors that affect the simulated oxygen concentrations in the wetland soil.
Mathilde Jammet, Sigrid Dengel, Ernesto Kettner, Frans-Jan W. Parmentier, Martin Wik, Patrick Crill, and Thomas Friborg
Biogeosciences, 14, 5189–5216, https://doi.org/10.5194/bg-14-5189-2017, https://doi.org/10.5194/bg-14-5189-2017, 2017
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The quantitative importance of northern lakes in terrestrial carbon budgets is uncertain, as year-round observations of carbon fluxes are rare. We measured CH4 and CO2 fluxes from a subarctic lake and nearby fen during 2.5 years with one eddy covariance system. We identified drivers of seasonal variability in lake fluxes and show the importance of winter and spring for annual carbon exchange in both ecosystems. The lake as a source of atmospheric carbon partially compensates the fen carbon sink.
Sarah E. Chadburn, Gerhard Krinner, Philipp Porada, Annett Bartsch, Christian Beer, Luca Belelli Marchesini, Julia Boike, Altug Ekici, Bo Elberling, Thomas Friborg, Gustaf Hugelius, Margareta Johansson, Peter Kuhry, Lars Kutzbach, Moritz Langer, Magnus Lund, Frans-Jan W. Parmentier, Shushi Peng, Ko Van Huissteden, Tao Wang, Sebastian Westermann, Dan Zhu, and Eleanor J. Burke
Biogeosciences, 14, 5143–5169, https://doi.org/10.5194/bg-14-5143-2017, https://doi.org/10.5194/bg-14-5143-2017, 2017
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Earth system models (ESMs) are our main tools for understanding future climate. The Arctic is important for the future carbon cycle, particularly due to the large carbon stocks in permafrost. We evaluated the performance of the land component of three major ESMs at Arctic tundra sites, focusing on the fluxes and stocks of carbon.
We show that the next steps for model improvement are to better represent vegetation dynamics, to include mosses and to improve below-ground carbon cycle processes.
Yao Gao, Tiina Markkanen, Mika Aurela, Ivan Mammarella, Tea Thum, Aki Tsuruta, Huiyi Yang, and Tuula Aalto
Biogeosciences, 14, 4409–4422, https://doi.org/10.5194/bg-14-4409-2017, https://doi.org/10.5194/bg-14-4409-2017, 2017
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We investigated the response of water use efficiency (WUE) to summer drought in a boreal Scots pine forest (Pinus sylvestris) on the daily time scale mainly using EC flux data from the Hyytiälä (southern Finland) flux site. Simulation results from the JSBACH land surface model were also evaluated against the observed results. The performance of three WUE metrics at the ecosystem level (EWUE, IWUE, and uWUE) during the severe summer drought were studied and showed different results.
Marielle Saunois, Philippe Bousquet, Ben Poulter, Anna Peregon, Philippe Ciais, Josep G. Canadell, Edward J. Dlugokencky, Giuseppe Etiope, David Bastviken, Sander Houweling, Greet Janssens-Maenhout, Francesco N. Tubiello, Simona Castaldi, Robert B. Jackson, Mihai Alexe, Vivek K. Arora, David J. Beerling, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Lori Bruhwiler, Cyril Crevoisier, Patrick Crill, Kristofer Covey, Christian Frankenberg, Nicola Gedney, Lena Höglund-Isaksson, Misa Ishizawa, Akihiko Ito, Fortunat Joos, Heon-Sook Kim, Thomas Kleinen, Paul Krummel, Jean-François Lamarque, Ray Langenfelds, Robin Locatelli, Toshinobu Machida, Shamil Maksyutov, Joe R. Melton, Isamu Morino, Vaishali Naik, Simon O'Doherty, Frans-Jan W. Parmentier, Prabir K. Patra, Changhui Peng, Shushi Peng, Glen P. Peters, Isabelle Pison, Ronald Prinn, Michel Ramonet, William J. Riley, Makoto Saito, Monia Santini, Ronny Schroeder, Isobel J. Simpson, Renato Spahni, Atsushi Takizawa, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Nicolas Viovy, Apostolos Voulgarakis, Ray Weiss, David J. Wilton, Andy Wiltshire, Doug Worthy, Debra Wunch, Xiyan Xu, Yukio Yoshida, Bowen Zhang, Zhen Zhang, and Qiuan Zhu
Atmos. Chem. Phys., 17, 11135–11161, https://doi.org/10.5194/acp-17-11135-2017, https://doi.org/10.5194/acp-17-11135-2017, 2017
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Following the Global Methane Budget 2000–2012 published in Saunois et al. (2016), we use the same dataset of bottom-up and top-down approaches to discuss the variations in methane emissions over the period 2000–2012. The changes in emissions are discussed both in terms of trends and quasi-decadal changes. The ensemble gathered here allows us to synthesise the robust changes in terms of regional and sectorial contributions to the increasing methane emissions.
Stefan Metzger, David Durden, Cove Sturtevant, Hongyan Luo, Natchaya Pingintha-Durden, Torsten Sachs, Andrei Serafimovich, Jörg Hartmann, Jiahong Li, Ke Xu, and Ankur R. Desai
Geosci. Model Dev., 10, 3189–3206, https://doi.org/10.5194/gmd-10-3189-2017, https://doi.org/10.5194/gmd-10-3189-2017, 2017
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We apply the
development and systems operationssoftware development model to create the eddy4R–Docker open-source, flexible, and modular eddy-covariance data processing environment. Test applications to aircraft and tower data, as well as a software cross validation demonstrate its efficiency and consistency. Key improvements in accessibility, extensibility, and reproducibility build the foundation for deploying complex scientific algorithms in an effective and scalable manner.
Pavel Alekseychik, Ivan Mammarella, Dmitry Karpov, Sigrid Dengel, Irina Terentieva, Alexander Sabrekov, Mikhail Glagolev, and Elena Lapshina
Atmos. Chem. Phys., 17, 9333–9345, https://doi.org/10.5194/acp-17-9333-2017, https://doi.org/10.5194/acp-17-9333-2017, 2017
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West Siberian peatlands occupy a large fraction of land area in the region, and yet little is known about their interaction with the atmosphere. We took the first measurements of CO2 and energy surface balances over a typical bog of West Siberian middle taiga, in the vicinity of the Mukhrino field station (Khanty–Mansiysk). The May–August study in a wet year (2015) revealed a relatively large photosynthetic sink of CO2 that was close to the high end of estimates at bog sites elsewhere.
Ting Sun, Zhi-Hua Wang, Walter C. Oechel, and Sue Grimmond
Geosci. Model Dev., 10, 2875–2890, https://doi.org/10.5194/gmd-10-2875-2017, https://doi.org/10.5194/gmd-10-2875-2017, 2017
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The diurnal hysteresis behaviour found between the net storage heat flux and net all-wave radiation has been captured in the Objective Hysteresis Model (OHM). To facilitate use, and enhance physical interpretations of the OHM coefficients, we develop the Analytical Objective Hysteresis Model (AnOHM) using an analytical solution of the one-dimensional advection–diffusion equation of coupled heat and liquid water transport in conjunction with the surface energy balance relationship.
Norbert Pirk, Jakob Sievers, Jordan Mertes, Frans-Jan W. Parmentier, Mikhail Mastepanov, and Torben R. Christensen
Biogeosciences, 14, 3157–3169, https://doi.org/10.5194/bg-14-3157-2017, https://doi.org/10.5194/bg-14-3157-2017, 2017
Tea Thum, Sönke Zaehle, Philipp Köhler, Tuula Aalto, Mika Aurela, Luis Guanter, Pasi Kolari, Tuomas Laurila, Annalea Lohila, Federico Magnani, Christiaan Van Der Tol, and Tiina Markkanen
Biogeosciences, 14, 1969–1987, https://doi.org/10.5194/bg-14-1969-2017, https://doi.org/10.5194/bg-14-1969-2017, 2017
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Modelling seasonal cycle at the coniferous forests poses a challenge. We implemented a model for sun-induced chlorophyll fluorescence (SIF) to a land surface model JSBACH. It was used to study the seasonality of the carbon cycle in the Fenno-Scandinavian region. Comparison was made to direct CO2 flux measurements and satellite observations of SIF. SIF proved to be a better proxy for photosynthesis than the fraction of absorbed photosynthetically active radiation.
Mika Korkiakoski, Juha-Pekka Tuovinen, Mika Aurela, Markku Koskinen, Kari Minkkinen, Paavo Ojanen, Timo Penttilä, Juuso Rainne, Tuomas Laurila, and Annalea Lohila
Biogeosciences, 14, 1947–1967, https://doi.org/10.5194/bg-14-1947-2017, https://doi.org/10.5194/bg-14-1947-2017, 2017
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We measured methane exchange rates at the forest floor of a nutrient-rich drained peatland in southern Finland. The forest floor acted mainly as a small methane sink, but emission peaks were occasionally observed during spring and rainfall events. The strength of the sink correlated best with groundwater level and soil temperatures at 20 and 30 cm depths. Diurnal variations were also observed but they were caused by changes in ambient wind speed and not by biological processes.
Matti Räsänen, Mika Aurela, Ville Vakkari, Johan P. Beukes, Juha-Pekka Tuovinen, Pieter G. Van Zyl, Miroslav Josipovic, Andrew D. Venter, Kerneels Jaars, Stefan J. Siebert, Tuomas Laurila, Janne Rinne, and Lauri Laakso
Biogeosciences, 14, 1039–1054, https://doi.org/10.5194/bg-14-1039-2017, https://doi.org/10.5194/bg-14-1039-2017, 2017
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This study presents measurements of carbon dioxide exchange between the atmosphere and a grazed savanna grassland ecosystem for 3 years. We find that the yearly variation in carbon dioxide balance is largely determined by the changes in the early wet season balance (September to November) and in the mid-growing season balance (December to January).
Kerry J. Dinsmore, Julia Drewer, Peter E. Levy, Charles George, Annalea Lohila, Mika Aurela, and Ute M. Skiba
Biogeosciences, 14, 799–815, https://doi.org/10.5194/bg-14-799-2017, https://doi.org/10.5194/bg-14-799-2017, 2017
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Release of greenhouse gases from northern soils contributes significantly to the global atmosphere and plays an important role in regulating climate. This study, based in N. Finland, aimed to measure and understand release of CH4 and N2O, and using satellite imagery, upscale our results to a 2 × 2 km area. Wetlands released large amounts of CH4, with emissions linked to temperature and the presence of Sphagnum; landscape emissions were 2.05 mg C m−2 hr−1. N2O fluxes were consistently near-zero.
Sonja Kaiser, Mathias Göckede, Karel Castro-Morales, Christian Knoblauch, Altug Ekici, Thomas Kleinen, Sebastian Zubrzycki, Torsten Sachs, Christian Wille, and Christian Beer
Geosci. Model Dev., 10, 333–358, https://doi.org/10.5194/gmd-10-333-2017, https://doi.org/10.5194/gmd-10-333-2017, 2017
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A new consistent, process-based methane module that is integrated with permafrost processes is presented. It was developed within a global land surface scheme and evaluated at a polygonal tundra site in Samoylov, Russia. The calculated methane emissions show fair agreement with field data and capture detailed differences between the explicitly modelled gas transport processes and in the gas dynamics under varying soil water and temperature conditions during seasons and on different microsites.
Mathias Hoffmann, Maximilian Schulz-Hanke, Juana Garcia Alba, Nicole Jurisch, Ulrike Hagemann, Torsten Sachs, Michael Sommer, and Jürgen Augustin
Atmos. Meas. Tech., 10, 109–118, https://doi.org/10.5194/amt-10-109-2017, https://doi.org/10.5194/amt-10-109-2017, 2017
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Processes driving production and transport of CH4 in wetlands are complex. We present an algorithm to separate open-water automatic chamber CH4 fluxes into diffusion and ebullition. This helps to reveal dynamics, identify drivers and obtain reliable CH4 emissions. The algorithm is based on sudden concentration changes during single measurements. A variable filter is applied using a multiple of the interquartile range. The algorithm was verified for data of a rewetted former fen grassland site.
Marielle Saunois, Philippe Bousquet, Ben Poulter, Anna Peregon, Philippe Ciais, Josep G. Canadell, Edward J. Dlugokencky, Giuseppe Etiope, David Bastviken, Sander Houweling, Greet Janssens-Maenhout, Francesco N. Tubiello, Simona Castaldi, Robert B. Jackson, Mihai Alexe, Vivek K. Arora, David J. Beerling, Peter Bergamaschi, Donald R. Blake, Gordon Brailsford, Victor Brovkin, Lori Bruhwiler, Cyril Crevoisier, Patrick Crill, Kristofer Covey, Charles Curry, Christian Frankenberg, Nicola Gedney, Lena Höglund-Isaksson, Misa Ishizawa, Akihiko Ito, Fortunat Joos, Heon-Sook Kim, Thomas Kleinen, Paul Krummel, Jean-François Lamarque, Ray Langenfelds, Robin Locatelli, Toshinobu Machida, Shamil Maksyutov, Kyle C. McDonald, Julia Marshall, Joe R. Melton, Isamu Morino, Vaishali Naik, Simon O'Doherty, Frans-Jan W. Parmentier, Prabir K. Patra, Changhui Peng, Shushi Peng, Glen P. Peters, Isabelle Pison, Catherine Prigent, Ronald Prinn, Michel Ramonet, William J. Riley, Makoto Saito, Monia Santini, Ronny Schroeder, Isobel J. Simpson, Renato Spahni, Paul Steele, Atsushi Takizawa, Brett F. Thornton, Hanqin Tian, Yasunori Tohjima, Nicolas Viovy, Apostolos Voulgarakis, Michiel van Weele, Guido R. van der Werf, Ray Weiss, Christine Wiedinmyer, David J. Wilton, Andy Wiltshire, Doug Worthy, Debra Wunch, Xiyan Xu, Yukio Yoshida, Bowen Zhang, Zhen Zhang, and Qiuan Zhu
Earth Syst. Sci. Data, 8, 697–751, https://doi.org/10.5194/essd-8-697-2016, https://doi.org/10.5194/essd-8-697-2016, 2016
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An accurate assessment of the methane budget is important to understand the atmospheric methane concentrations and trends and to provide realistic pathways for climate change mitigation. The various and diffuse sources of methane as well and its oxidation by a very short lifetime radical challenge this assessment. We quantify the methane sources and sinks as well as their uncertainties based on both bottom-up and top-down approaches provided by a broad international scientific community.
Jarmo Mäkelä, Jouni Susiluoto, Tiina Markkanen, Mika Aurela, Heikki Järvinen, Ivan Mammarella, Stefan Hagemann, and Tuula Aalto
Nonlin. Processes Geophys., 23, 447–465, https://doi.org/10.5194/npg-23-447-2016, https://doi.org/10.5194/npg-23-447-2016, 2016
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The land-based hydrological cycle is one of the key processes controlling the growth and wilting of plants and the amount of carbon vegetation can assimilate. Recent studies have shown that many land surface models have biases in this area. We optimized parameters in one such model (JSBACH) and were able to enhance the model performance in many respects, but the response to drought remained unaffected. Further studies into this aspect should include alternative stomatal conductance formulations.
Xiyan Xu, William J. Riley, Charles D. Koven, Dave P. Billesbach, Rachel Y.-W. Chang, Róisín Commane, Eugénie S. Euskirchen, Sean Hartery, Yoshinobu Harazono, Hiroki Iwata, Kyle C. McDonald, Charles E. Miller, Walter C. Oechel, Benjamin Poulter, Naama Raz-Yaseef, Colm Sweeney, Margaret Torn, Steven C. Wofsy, Zhen Zhang, and Donatella Zona
Biogeosciences, 13, 5043–5056, https://doi.org/10.5194/bg-13-5043-2016, https://doi.org/10.5194/bg-13-5043-2016, 2016
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Wetlands are the largest global natural methane source. Peat-rich bogs and fens lying between 50°N and 70°N contribute 10–30% to this source. The predictive capability of the seasonal methane cycle can directly affect the estimation of global methane budget. We present multiscale methane seasonal emission by observations and modeling and find that the uncertainties in predicting the seasonal methane emissions are from the wetland extent, cold-season CH4 production and CH4 transport processes.
Maiju Linkosalmi, Mika Aurela, Juha-Pekka Tuovinen, Mikko Peltoniemi, Cemal M. Tanis, Ali N. Arslan, Pasi Kolari, Kristin Böttcher, Tuula Aalto, Juuso Rainne, Juha Hatakka, and Tuomas Laurila
Geosci. Instrum. Method. Data Syst., 5, 417–426, https://doi.org/10.5194/gi-5-417-2016, https://doi.org/10.5194/gi-5-417-2016, 2016
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Digital photography has become a widely used tool for monitoring the vegetation phenology. The seasonal cycle of the greenness index obtained from photographs correlated well with the CO2 exchange of the plants at our wetland and Scots pine forest sites. While the seasonal changes in the greenness were more obvious for the ecosystem dominated by annual plants, clear seasonal patterns were also observed for the evergreen forest.
Daniela Franz, Franziska Koebsch, Eric Larmanou, Jürgen Augustin, and Torsten Sachs
Biogeosciences, 13, 3051–3070, https://doi.org/10.5194/bg-13-3051-2016, https://doi.org/10.5194/bg-13-3051-2016, 2016
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Based on the eddy covariance method we investigate the ecosystem–atmosphere exchange of CH4 and CO2 at a eutrophic shallow lake as a challenging ecosystem often evolving during peatland rewetting. Both open water and emergent vegetation are net emitters of CH4 and CO2, but with strikingly different release rates. Even after 9 years of rewetting the lake ecosystem exhibits a considerable carbon loss and global warming impact, the latter mainly driven by high CH4 emissions from the open waterbody.
Markku Kangas, Laura Rontu, Carl Fortelius, Mika Aurela, and Antti Poikonen
Geosci. Instrum. Method. Data Syst., 5, 75–84, https://doi.org/10.5194/gi-5-75-2016, https://doi.org/10.5194/gi-5-75-2016, 2016
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Sodankylä, in the heart of the Arctic Research Centre of the Finnish Meteorological Institute in northern Finland with temperatures ranging from −50 to +30 °C, provides a challenging location for numerical weather forecasting (NWP) models. In this article, the use of measurements performed in Sodankylä for near-real time online verification of NWP models is described. A more specific case study of three different radiation schemes, applicable in NWP model HARMONIE-AROME, is also presented.
Norbert Pirk, Mikhail Mastepanov, Frans-Jan W. Parmentier, Magnus Lund, Patrick Crill, and Torben R. Christensen
Biogeosciences, 13, 903–912, https://doi.org/10.5194/bg-13-903-2016, https://doi.org/10.5194/bg-13-903-2016, 2016
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The exchange of greenhouse gases between the land and the atmosphere is often measured by monitoring the gas concentrations inside a chamber which is placed on the ground. We investigated different ways to calculate the gas exchange rate and identified several different processes which influence the gas exchange measurement.
E. Asmi, V. Kondratyev, D. Brus, T. Laurila, H. Lihavainen, J. Backman, V. Vakkari, M. Aurela, J. Hatakka, Y. Viisanen, T. Uttal, V. Ivakhov, and A. Makshtas
Atmos. Chem. Phys., 16, 1271–1287, https://doi.org/10.5194/acp-16-1271-2016, https://doi.org/10.5194/acp-16-1271-2016, 2016
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Aerosol number size distributions were measured in Arctic Russia continuously during 4 years. The particles' seasonal characteristics and sources were identified based on these data. In early spring, elevated concentrations were detected during episodes of Arctic haze and during days of secondary particle formation. In summer, Siberian forests biogenic emissions had a significant impact on particle number and mass. These are the first such results obtained from the region.
Y. Gao, T. Markkanen, T. Thum, M. Aurela, A. Lohila, I. Mammarella, M. Kämäräinen, S. Hagemann, and T. Aalto
Hydrol. Earth Syst. Sci., 20, 175–191, https://doi.org/10.5194/hess-20-175-2016, https://doi.org/10.5194/hess-20-175-2016, 2016
J. E. Vonk, S. E. Tank, W. B. Bowden, I. Laurion, W. F. Vincent, P. Alekseychik, M. Amyot, M. F. Billet, J. Canário, R. M. Cory, B. N. Deshpande, M. Helbig, M. Jammet, J. Karlsson, J. Larouche, G. MacMillan, M. Rautio, K. M. Walter Anthony, and K. P. Wickland
Biogeosciences, 12, 7129–7167, https://doi.org/10.5194/bg-12-7129-2015, https://doi.org/10.5194/bg-12-7129-2015, 2015
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In this review, we give an overview of the current state of knowledge regarding how permafrost thaw affects aquatic systems. We describe the general impacts of thaw on aquatic ecosystems, pathways of organic matter and contaminant release and degradation, resulting emissions and burial, and effects on ecosystem structure and functioning. We conclude with an overview of potential climate effects and recommendations for future research.
T. Li, W. Zhang, Q. Zhang, Y. Lu, G. Wang, Z. Niu, M. Raivonen, and T. Vesala
Biogeosciences, 12, 6853–6868, https://doi.org/10.5194/bg-12-6853-2015, https://doi.org/10.5194/bg-12-6853-2015, 2015
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Natural wetlands in China have experienced extensive conversion and climate warming, which makes the estimation of methane emission from wetlands highly uncertain. In this paper, we simulated an increase of 25.5% in national CH4 fluxes from 1950 to 2010, which was mainly induced by climate warming. Although climate warming has accelerated CH4 fluxes, the total amount of national CH4 emissions decreased by approximately 2.35 Tg (1.91－2.81 Tg), due to a large wetland loss of 17.0 million ha.
M. Hoffmann, M. Schulz-Hanke, J. Garcia Alba, N. Jurisch, U. Hagemann, T. Sachs, M. Sommer, and J. Augustin
Biogeosciences Discuss., https://doi.org/10.5194/bgd-12-12923-2015, https://doi.org/10.5194/bgd-12-12923-2015, 2015
Manuscript not accepted for further review
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Processes driving the production, transformation and transport of CH4 in wetlands are highly complex. Thus, serious challenges are constitutes in terms of process understanding, potential drivers and the calculation of reliable CH4 emission estimates. We present a simple calculation algorithm to separate CH4 fluxes measured with closed chambers into diffusion- and ebullition-derived components, which helps facilitating the identification of underlying dynamics and potential drivers.
S. Dengel, J. Grace, and A. MacArthur
Biogeosciences, 12, 4195–4207, https://doi.org/10.5194/bg-12-4195-2015, https://doi.org/10.5194/bg-12-4195-2015, 2015
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We tested the hypothesis that diffuse radiation from cloudy and overcast skies penetrates the canopy more effectively than direct radiation from clear skies. We compared the flux density and spectral properties of direct and diffuse radiation above, within and below a forest stand under sunny, cloudy and overcast conditions in a thinned Sitka spruce forest. We recorded vertical (1m resolution) and horizontal (2.5m resolution) profiles of radiation penetration at 1nm resolution.
F. Minunno, M. Peltoniemi, S. Launiainen, M. Aurela, A. Lindroth, A. Lohila, I. Mammarella, K. Minkkinen, and A. Mäkelä
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmdd-8-5089-2015, https://doi.org/10.5194/gmdd-8-5089-2015, 2015
Revised manuscript not accepted
T. De Groote, D. Zona, L. S. Broeckx, M. S. Verlinden, S. Luyssaert, V. Bellassen, N. Vuichard, R. Ceulemans, A. Gobin, and I. A. Janssens
Geosci. Model Dev., 8, 1461–1471, https://doi.org/10.5194/gmd-8-1461-2015, https://doi.org/10.5194/gmd-8-1461-2015, 2015
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This paper describes the modification of the widely used land surface model ORCHIDEE for stand-scale simulations of short rotation coppice (SRC) plantations. The modifications presented in this paper were evaluated using data from two Belgian poplar-based SRC sites, for which multiple measurements and meteorological data were available. The simulations show that the model predicts aboveground biomass production, ecosystem photosynthesis and ecosystem respiration well.
J. Sievers, T. Papakyriakou, S. E. Larsen, M. M. Jammet, S. Rysgaard, M. K. Sejr, and L. L. Sørensen
Atmos. Chem. Phys., 15, 2081–2103, https://doi.org/10.5194/acp-15-2081-2015, https://doi.org/10.5194/acp-15-2081-2015, 2015
Ü. Rannik, S. Haapanala, N. J. Shurpali, I. Mammarella, S. Lind, N. Hyvönen, O. Peltola, M. Zahniser, P. J. Martikainen, and T. Vesala
Biogeosciences, 12, 415–432, https://doi.org/10.5194/bg-12-415-2015, https://doi.org/10.5194/bg-12-415-2015, 2015
B. Tupek, K. Minkkinen, J. Pumpanen, T. Vesala, and E. Nikinmaa
Biogeosciences, 12, 281–297, https://doi.org/10.5194/bg-12-281-2015, https://doi.org/10.5194/bg-12-281-2015, 2015
C. Metzger, P.-E. Jansson, A. Lohila, M. Aurela, T. Eickenscheidt, L. Belelli-Marchesini, K. J. Dinsmore, J. Drewer, J. van Huissteden, and M. Drösler
Biogeosciences, 12, 125–146, https://doi.org/10.5194/bg-12-125-2015, https://doi.org/10.5194/bg-12-125-2015, 2015
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To identify site specific differences in CO2-related processes in open peatlands, we calibrated a process oriented model to fit to detailed measurements of carbon fluxes and compared the resulting parameter ranges between the sites. For most processes a common configuration could be applied. Site specific differences were identified for soil respiration coefficients, plant radiation-use efficiencies and plant storage fractions for spring regrowth.
S. J. O'Shea, G. Allen, M. W. Gallagher, K. Bower, S. M. Illingworth, J. B. A. Muller, B. T. Jones, C. J. Percival, S. J-B. Bauguitte, M. Cain, N. Warwick, A. Quiquet, U. Skiba, J. Drewer, K. Dinsmore, E. G. Nisbet, D. Lowry, R. E. Fisher, J. L. France, M. Aurela, A. Lohila, G. Hayman, C. George, D. B. Clark, A. J. Manning, A. D. Friend, and J. Pyle
Atmos. Chem. Phys., 14, 13159–13174, https://doi.org/10.5194/acp-14-13159-2014, https://doi.org/10.5194/acp-14-13159-2014, 2014
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This paper presents airborne measurements of greenhouse gases collected in the European Arctic. Regional scale flux estimates for the northern Scandinavian wetlands are derived. These fluxes are found to be in excellent agreement with coincident surface measurements within the aircraft's sampling domain. This has allowed a significant low bias to be identified in two commonly used process-based land surface models.
D. Zona, D. A. Lipson, J. H. Richards, G. K. Phoenix, A. K. Liljedahl, M. Ueyama, C. S. Sturtevant, and W. C. Oechel
Biogeosciences, 11, 5877–5888, https://doi.org/10.5194/bg-11-5877-2014, https://doi.org/10.5194/bg-11-5877-2014, 2014
H. N. Mbufong, M. Lund, M. Aurela, T. R. Christensen, W. Eugster, T. Friborg, B. U. Hansen, E. R. Humphreys, M. Jackowicz-Korczynski, L. Kutzbach, P. M. Lafleur, W. C. Oechel, F. J. W. Parmentier, D. P. Rasse, A. V. Rocha, T. Sachs, M. K. van der Molen, and M. P. Tamstorf
Biogeosciences, 11, 4897–4912, https://doi.org/10.5194/bg-11-4897-2014, https://doi.org/10.5194/bg-11-4897-2014, 2014
A. Budishchev, Y. Mi, J. van Huissteden, L. Belelli-Marchesini, G. Schaepman-Strub, F. J. W. Parmentier, G. Fratini, A. Gallagher, T. C. Maximov, and A. J. Dolman
Biogeosciences, 11, 4651–4664, https://doi.org/10.5194/bg-11-4651-2014, https://doi.org/10.5194/bg-11-4651-2014, 2014
Q. Zhu, Q. Zhuang, D. Henze, K. Bowman, M. Chen, Y. Liu, Y. He, H. Matsueda, T. Machida, Y. Sawa, and W. Oechel
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acpd-14-22587-2014, https://doi.org/10.5194/acpd-14-22587-2014, 2014
Revised manuscript not accepted
J. B. Fisher, M. Sikka, W. C. Oechel, D. N. Huntzinger, J. R. Melton, C. D. Koven, A. Ahlström, M. A. Arain, I. Baker, J. M. Chen, P. Ciais, C. Davidson, M. Dietze, B. El-Masri, D. Hayes, C. Huntingford, A. K. Jain, P. E. Levy, M. R. Lomas, B. Poulter, D. Price, A. K. Sahoo, K. Schaefer, H. Tian, E. Tomelleri, H. Verbeeck, N. Viovy, R. Wania, N. Zeng, and C. E. Miller
Biogeosciences, 11, 4271–4288, https://doi.org/10.5194/bg-11-4271-2014, https://doi.org/10.5194/bg-11-4271-2014, 2014
Y. Mi, J. van Huissteden, F. J. W. Parmentier, A. Gallagher, A. Budishchev, C. T. Berridge, and A. J. Dolman
Biogeosciences, 11, 3985–3999, https://doi.org/10.5194/bg-11-3985-2014, https://doi.org/10.5194/bg-11-3985-2014, 2014
J. D. Watts, J. S. Kimball, F. J. W. Parmentier, T. Sachs, J. Rinne, D. Zona, W. Oechel, T. Tagesson, M. Jackowicz-Korczyński, and M. Aurela
Biogeosciences, 11, 1961–1980, https://doi.org/10.5194/bg-11-1961-2014, https://doi.org/10.5194/bg-11-1961-2014, 2014
K. Wang, C. Liu, X. Zheng, M. Pihlatie, B. Li, S. Haapanala, T. Vesala, H. Liu, Y. Wang, G. Liu, and F. Hu
Biogeosciences, 10, 6865–6877, https://doi.org/10.5194/bg-10-6865-2013, https://doi.org/10.5194/bg-10-6865-2013, 2013
H. Ikawa, I. Faloona, J. Kochendorfer, K. T. Paw U, and W. C. Oechel
Biogeosciences, 10, 4419–4432, https://doi.org/10.5194/bg-10-4419-2013, https://doi.org/10.5194/bg-10-4419-2013, 2013
O. Peltola, I. Mammarella, S. Haapanala, G. Burba, and T. Vesala
Biogeosciences, 10, 3749–3765, https://doi.org/10.5194/bg-10-3749-2013, https://doi.org/10.5194/bg-10-3749-2013, 2013
B. R. K. Runkle, T. Sachs, C. Wille, E.-M. Pfeiffer, and L. Kutzbach
Biogeosciences, 10, 1337–1349, https://doi.org/10.5194/bg-10-1337-2013, https://doi.org/10.5194/bg-10-1337-2013, 2013
J. F. J. Korhonen, M. Pihlatie, J. Pumpanen, H. Aaltonen, P. Hari, J. Levula, A.-J. Kieloaho, E. Nikinmaa, T. Vesala, and H. Ilvesniemi
Biogeosciences, 10, 1083–1095, https://doi.org/10.5194/bg-10-1083-2013, https://doi.org/10.5194/bg-10-1083-2013, 2013
T. Krings, K. Gerilowski, M. Buchwitz, J. Hartmann, T. Sachs, J. Erzinger, J. P. Burrows, and H. Bovensmann
Atmos. Meas. Tech., 6, 151–166, https://doi.org/10.5194/amt-6-151-2013, https://doi.org/10.5194/amt-6-151-2013, 2013
G. Lasslop, M. Migliavacca, G. Bohrer, M. Reichstein, M. Bahn, A. Ibrom, C. Jacobs, P. Kolari, D. Papale, T. Vesala, G. Wohlfahrt, and A. Cescatti
Biogeosciences, 9, 5243–5259, https://doi.org/10.5194/bg-9-5243-2012, https://doi.org/10.5194/bg-9-5243-2012, 2012
Related subject area
Biogeochemistry: Greenhouse Gases
Water flow controls the spatial variability of methane emissions in a northern valley fen ecosystem
Seasonality, drivers, and isotopic composition of soil CO2 fluxes from tropical forests of the Congo Basin
Spatially resolved evaluation of Earth system models with satellite column-averaged CO2
Ideas and perspectives: A strategic assessment of methane and nitrous oxide measurements in the marine environment
Stem and soil nitrous oxide fluxes from rainforest and cacao agroforest on highly weathered soils in the Congo Basin
Methane paradox in tropical lakes? Sedimentary fluxes rather than pelagic production in oxic conditions sustain methanotrophy and emissions to the atmosphere
Carbon dioxide and methane exchange of a patterned subarctic fen during two contrasting growing seasons
Organic matter and sediment properties determine in-lake variability of sediment CO2 and CH4 production and emissions of a small and shallow lake
Evaluating stream CO2 outgassing via Drifting and Anchored flux chambers in a controlled flume experiment
Mineralization of organic matter in boreal lake sediments: rates, pathways, and nature of the fermenting substrates
Estimating immediate post-fire carbon fluxes using the eddy-covariance technique
Using satellite data to identify the methane emission controls of South Sudan's wetlands
Technical note: Facilitating the use of low-cost methane (CH4) sensors in flux chambers – calibration, data processing, and an open-source make-it-yourself logger
N2O changes from the Last Glacial Maximum to the preindustrial – Part 2: terrestrial N2O emissions and carbon–nitrogen cycle interactions
Carbon dioxide and methane fluxes from different surface types in a created urban wetland
A decade of methane measurements at the Boknis Eck Time Series Station in Eckernförde Bay (southwestern Baltic Sea)
Dissolved CH4 coupled to photosynthetic picoeukaryotes in oxic waters and to cumulative chlorophyll a in anoxic waters of reservoirs
Carbon dioxide dynamics in an agricultural headwater stream driven by hydrology and primary production
Decadal variation in CO2 fluxes and its budget in a wheat and maize rotation cropland over the North China Plain
Soil greenhouse gas emissions under different land-use types in savanna ecosystems of Kenya
Seasonality of greenhouse gas emission factors from biomass burning in the Brazilian Cerrado
Warming enhances carbon dioxide and methane fluxes from Red Sea seagrass (Halophila stipulacea) sediments
CO2, CH4 and N2O fluxes along an altitudinal gradient in the northern Ecuadorean Andes: N2O consumption at higher altitudes
Carbon–nitrogen interactions in European forests and semi-natural vegetation – Part 1: Fluxes and budgets of carbon, nitrogen and greenhouse gases from ecosystem monitoring and modelling
Carbon–nitrogen interactions in European forests and semi-natural vegetation – Part 2: Untangling climatic, edaphic, management and nitrogen deposition effects on carbon sequestration potentials
Maize root and shoot litter quality controls short-term CO2 and N2O emissions and bacterial community structure of arable soil
The carbon footprint of a Malaysian tropical reservoir: measured versus modelled estimates highlight the underestimated key role of downstream processes
Effect of legume intercropping on N2O emissions and CH4 uptake during maize production in the Great Rift Valley, Ethiopia
Regulation of N2O emissions from acid organic soil drained for agriculture
Nitrous oxide (N2O) and methane (CH4) in rivers and estuaries of northwestern Borneo
Regulation of carbon dioxide and methane in small agricultural reservoirs: optimizing potential for greenhouse gas uptake
Methane production by three widespread marine phytoplankton species: release rates, precursor compounds, and potential relevance for the environment
CO2 and CH4 budgets and global warming potential modifications in Sphagnum-dominated peat mesocosms invaded by Molinia caerulea
A multi-year observation of nitrous oxide at the Boknis Eck Time Series Station in the Eckernförde Bay (southwestern Baltic Sea)
Air–sea fluxes of greenhouse gases and oxygen in the northern Benguela Current region during upwelling events
N2O changes from the Last Glacial Maximum to the preindustrial – Part 1: Quantitative reconstruction of terrestrial and marine emissions using N2O stable isotopes in ice cores
Variations in dissolved greenhouse gases (CO2, CH4, N2O) in the Congo River network overwhelmingly driven by fluvial-wetland connectivity
Greenhouse gas and energy fluxes in a boreal peatland forest after clear-cutting
Carbon dioxide (CO2) concentrations and emission in the newly constructed Belo Monte hydropower complex in the Xingu River, Amazonia
Technical note: Interferences of volatile organic compounds (VOCs) on methane concentration measurements
Applicability and consequences of the integration of alternative models for CO2 transfer velocity into a process-based lake model
Attribution of N2O sources in a grassland soil with laser spectroscopy based isotopocule analysis
The ratio of methanogens to methanotrophs and water-level dynamics drive methane transfer velocity in a temperate kettle-hole peat bog
Technical Note: Isotopic corrections for the radiocarbon composition of CO2 in the soil gas environment must account for diffusion and diffusive mixing
Quantifying the impact of emission outbursts and non-stationary flow on eddy-covariance CH4 flux measurements using wavelet techniques
Ideas and perspectives: is shale gas a major driver of recent increase in global atmospheric methane?
Reviews and syntheses: Review of causes and sources of N2O emissions and NO3 leaching from organic arable crop rotations
Wildfire overrides hydrological controls on boreal peatland methane emissions
Scaling and balancing carbon dioxide fluxes in a heterogeneous tundra ecosystem of the Lena River Delta
Physically controlled CO2 effluxes from a reservoir surface in the upper Mekong River Basin: a case study in the Gongguoqiao Reservoir
Hui Zhang, Eeva-Stiina Tuittila, Aino Korrensalo, Aleksi Räsänen, Tarmo Virtanen, Mika Aurela, Timo Penttilä, Tuomas Laurila, Stephanie Gerin, Viivi Lindholm, and Annalea Lohila
Biogeosciences, 17, 6247–6270, https://doi.org/10.5194/bg-17-6247-2020, https://doi.org/10.5194/bg-17-6247-2020, 2020
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We studied the impact of a stream on peatland microhabitats and CH4 emissions in a northern boreal fen. We found that there were higher water levels, lower peat temperatures, and greater oxygen concentrations close to the stream; these supported the highest biomass production but resulted in the lowest CH4 emissions. Further from the stream, the conditions were drier and CH4 emissions were also low. CH4 emissions were highest at an intermediate distance from the stream.
Simon Baumgartner, Matti Barthel, Travis William Drake, Marijn Bauters, Isaac Ahanamungu Makelele, John Kalume Mugula, Laura Summerauer, Nora Gallarotti, Landry Cizungu Ntaboba, Kristof Van Oost, Pascal Boeckx, Sebastian Doetterl, Roland Anton Werner, and Johan Six
Biogeosciences, 17, 6207–6218, https://doi.org/10.5194/bg-17-6207-2020, https://doi.org/10.5194/bg-17-6207-2020, 2020
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Soil respiration is an important carbon flux and key process determining the net ecosystem production of terrestrial ecosystems. The Congo Basin lacks studies quantifying carbon fluxes. We measured soil CO2 fluxes from different forest types in the Congo Basin and were able to show that, even though soil CO2 fluxes are similarly high in lowland and montane forests, the drivers were different: soil moisture in montane forests and C availability in the lowland forests.
Bettina K. Gier, Michael Buchwitz, Maximilian Reuter, Peter M. Cox, Pierre Friedlingstein, and Veronika Eyring
Biogeosciences, 17, 6115–6144, https://doi.org/10.5194/bg-17-6115-2020, https://doi.org/10.5194/bg-17-6115-2020, 2020
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Models from Coupled Model Intercomparison Project (CMIP) phases 5 and 6 are compared to a satellite data product of column-averaged CO2 mole fractions (XCO2). The previously believed discrepancy of the negative trend in seasonal cycle amplitude in the satellite product, which is not seen in in situ data nor in the models, is attributed to a sampling characteristic. Furthermore, CMIP6 models are shown to have made progress in reproducing the observed XCO2 time series compared to CMIP5.
Samuel T. Wilson, Alia N. Al-Haj, Annie Bourbonnais, Claudia Frey, Robinson W. Fulweiler, John D. Kessler, Hannah K. Marchant, Jana Milucka, Nicholas E. Ray, Parvadha Suntharalingam, Brett F. Thornton, Robert C. Upstill-Goddard, Thomas S. Weber, Damian L. Arévalo-Martínez, Hermann W. Bange, Heather M. Benway, Daniele Bianchi, Alberto V. Borges, Bonnie X. Chang, Patrick M. Crill, Daniela A. del Valle, Laura Farías, Samantha B. Joye, Annette Kock, Jabrane Labidi, Cara C. Manning, John W. Pohlman, Gregor Rehder, Katy J. Sparrow, Philippe D. Tortell, Tina Treude, David L. Valentine, Bess B. Ward, Simon Yang, and Leonid N. Yurganov
Biogeosciences, 17, 5809–5828, https://doi.org/10.5194/bg-17-5809-2020, https://doi.org/10.5194/bg-17-5809-2020, 2020
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The oceans are a net source of the major greenhouse gases; however there has been little coordination of oceanic methane and nitrous oxide measurements. The scientific community has recently embarked on a series of capacity-building exercises to improve the interoperability of dissolved methane and nitrous oxide measurements. This paper derives from a workshop which discussed the challenges and opportunities for oceanic methane and nitrous oxide research in the near future.
Najeeb Al-Amin Iddris, Marife D. Corre, Martin Yemefack, Oliver van Straaten, and Edzo Veldkamp
Biogeosciences, 17, 5377–5397, https://doi.org/10.5194/bg-17-5377-2020, https://doi.org/10.5194/bg-17-5377-2020, 2020
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We quantified the changes in stem and soil nitrous oxide (N2O) fluxes with forest conversion to cacao agroforestry in the Congo Basin, Cameroon. All forest and cacao trees consistently emitted N2O, contributing 8–38 % of the total (soil and stem) emissions. Forest conversion to extensively managed (>–20 years old) cacao agroforestry had no effect on stem and soil N2O fluxes. Our results highlight the importance of including tree-mediated fluxes in the ecosystem-level N2O budget.
Cédric Morana, Steven Bouillon, Vimac Nolla-Ardèvol, Fleur A. E. Roland, William Okello, Jean-Pierre Descy, Angela Nankabirwa, Erina Nabafu, Dirk Springael, and Alberto V. Borges
Biogeosciences, 17, 5209–5221, https://doi.org/10.5194/bg-17-5209-2020, https://doi.org/10.5194/bg-17-5209-2020, 2020
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A growing body of studies challenges the paradigm that methane (CH4) production occurs only under anaerobic conditions. Our field experiments revealed that oxic CH4 production is closely related to phytoplankton metabolism and is indeed a common feature in five contrasting African lakes. Nevertheless, we found that methanotrophic activity in surface waters and CH4 emissions to the atmosphere were predominantly fuelled by CH4 generated in sediments and physically transported to the surface.
Lauri Heiskanen, Juha-Pekka Tuovinen, Aleksi Räsänen, Tarmo Virtanen, Sari Juutinen, Annalea Lohila, Timo Penttilä, Maiju Linkosalmi, Juha Mikola, Tuomas Laurila, and Mika Aurela
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-370, https://doi.org/10.5194/bg-2020-370, 2020
Revised manuscript accepted for BG
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We studied ecosystem and plant community level carbon (C) exchange between subarctic mire and the atmosphere during 2017–2018. We found strong spatial variation in CO2 and CH4 dynamics between the main plant communities. The earlier onset of growing season in 2018 strengthened the CO2 sink of the ecosystem, but this gain was counterbalanced by a later drought period. Variation in water table level, soil temperature and vegetation explained most of the variation in the ecosystem level C exchange.
Leandra Stephanie Emilia Praetzel, Nora Plenter, Sabrina Schilling, Marcel Schmiedeskamp, Gabriele Broll, and Klaus-Holger Knorr
Biogeosciences, 17, 5057–5078, https://doi.org/10.5194/bg-17-5057-2020, https://doi.org/10.5194/bg-17-5057-2020, 2020
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Small lakes are important but variable sources of greenhouse gas emissions. We performed lab experiments to determine spatial patterns and drivers of CO2 and CH4 emission and sediment gas production within a lake. The observed high spatial variability of emissions and production could be explained by the degradability of the sediment organic matter. We did not see correlations between production and emissions and suggest on-site flux measurements as the most accurate way for determing emissions.
Filippo Vingiani, Nicola Durighetto, Marcus Klaus, Jakob Schelker, Thierry Labasque, and Gianluca Botter
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-327, https://doi.org/10.5194/bg-2020-327, 2020
Revised manuscript accepted for BG
François Clayer, Yves Gélinas, André Tessier, and Charles Gobeil
Biogeosciences, 17, 4571–4589, https://doi.org/10.5194/bg-17-4571-2020, https://doi.org/10.5194/bg-17-4571-2020, 2020
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Here, we quantified the sediment production of methane and carbon dioxide in lake sediments to better characterize the nature of the organic matter at the origin of these two greenhouse gases. We demonstrate that the production of these gases is not adequately represented in models for deep lake sediments. We thus propose to improve the representation of organic matter degradation reactions in current models for improving predictions of greenhouse gas cycling in aquatic sediments.
Bruna R. F. Oliveira, Carsten Schaller, J. Jacob Keizer, and Thomas Foken
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-312, https://doi.org/10.5194/bg-2020-312, 2020
Revised manuscript accepted for BG
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Forest fires have a significant impact on carbon dioxide emissions. The present study from pine forest in Portugal is one of the few where measurements of CO2 fluxes were started immediately (one and a half months) after the forest fire. Carbon dioxide emissions were linked to soil humidiy. Therefore, they started after the beginning of the rainfall in autumn. Due to the beginning of vegetation, the site was already a carbon dioxide sink the following year.
Sudhanshu Pandey, Sander Houweling, Alba Lorente, Tobias Borsdorff, Maria Tsivlidou, A. Anthony Bloom, Benjamin Poulter, Zhen Zhang, and Ilse Aben
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-251, https://doi.org/10.5194/bg-2020-251, 2020
Revised manuscript accepted for BG
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We use atmospheric methane observations from the novel TROPOMI (Sentinel-5p) satellite instrument to estimate methane emissions from South Sudan's wetlands. Our emission estimates are an order of magnitude larger than the estimate of process-based wetland models. We find that this underestimation by the models is likely due to their misrepresentation of the wetlands' inundation extent and temperature dependences.
David Bastviken, Jonatan Nygren, Jonathan Schenk, Roser Parellada Massana, and Nguyen Thanh Duc
Biogeosciences, 17, 3659–3667, https://doi.org/10.5194/bg-17-3659-2020, https://doi.org/10.5194/bg-17-3659-2020, 2020
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This study presents a low-cost way to measure methane emissions applicable in nature and society. This facilitates widespread and affordable methane measurements, which are greatly needed for verifying that greenhouse gas mitigation is effective and for improved quantification of fluxes and how they are regulated. The paper also describes an open-source do-it-yourself methane–carbon dioxide–humidity–temperature logger, to increase the distributed capacity to measure greenhouse gases.
Fortunat Joos, Renato Spahni, Benjamin D. Stocker, Sebastian Lienert, Jurek Müller, Hubertus Fischer, Jochen Schmitt, I. Colin Prentice, Bette Otto-Bliesner, and Zhengyu Liu
Biogeosciences, 17, 3511–3543, https://doi.org/10.5194/bg-17-3511-2020, https://doi.org/10.5194/bg-17-3511-2020, 2020
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Results of the first globally resolved simulations of terrestrial carbon and nitrogen (N) cycling and N2O emissions over the past 21 000 years are compared with reconstructed N2O emissions. Modelled and reconstructed emissions increased strongly during past abrupt warming events. This evidence appears consistent with a dynamic response of biological N fixation to increasing N demand by ecosystems, thereby reducing N limitation of plant productivity and supporting a land sink for atmospheric CO2.
Xuefei Li, Outi Wahlroos, Sami Haapanala, Jukka Pumpanen, Harri Vasander, Anne Ojala, Timo Vesala, and Ivan Mammarella
Biogeosciences, 17, 3409–3425, https://doi.org/10.5194/bg-17-3409-2020, https://doi.org/10.5194/bg-17-3409-2020, 2020
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We measured CO2 and CH4 fluxes and quantified the global warming potential of different surface areas in a recently created urban wetland in Southern Finland. The ecosystem has a small net climate warming effect which was mainly contributed by the open-water areas. Our results suggest that limiting open-water areas and setting a design preference for areas of emergent vegetation in the establishment of urban wetlands can be a beneficial practice when considering solely the climate impact.
Xiao Ma, Mingshuang Sun, Sinikka T. Lennartz, and Hermann W. Bange
Biogeosciences, 17, 3427–3438, https://doi.org/10.5194/bg-17-3427-2020, https://doi.org/10.5194/bg-17-3427-2020, 2020
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Monthly measurements of dissolved methane (CH4), a potent greenhouse gas, were conducted at Boknis Eck (BE), a time-series station in the southwestern Baltic Sea, from June 2006. In general CH4 concentrations increased with depth. High concentrations in the upper layer were linked to saline water inflow. Eckernförde Bay emitted CH4 to the atmosphere throughout the monitoring period. No significant trend was detected in CH4 concentrations or emissions during 2006–2017.
Elizabeth León-Palmero, Alba Contreras-Ruiz, Ana Sierra, Rafael Morales-Baquero, and Isabel Reche
Biogeosciences, 17, 3223–3245, https://doi.org/10.5194/bg-17-3223-2020, https://doi.org/10.5194/bg-17-3223-2020, 2020
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CH4 emissions from reservoirs are responsible for the majority of the climatic forcing of these ecosystems. The origin of the recurrent CH4 supersaturation in oxic waters is still controversial. We found that the dissolved CH4 concentration varied by up to 4 orders of magnitude in the water column of 12 reservoirs and was consistently supersaturated. Our findings suggest that photosynthetic picoeukaryotes can play a significant role in determining CH4 concentration in oxic waters.
Marcus B. Wallin, Joachim Audet, Mike Peacock, Erik Sahlée, and Mattias Winterdahl
Biogeosciences, 17, 2487–2498, https://doi.org/10.5194/bg-17-2487-2020, https://doi.org/10.5194/bg-17-2487-2020, 2020
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Here we show that small streams draining agricultural areas are potential hotspots for emissions of CO2 to the atmosphere. We further conclude that the variability in stream CO2 concentration over time is very high, caused by variations in both water discharge and primary production. Given the observed high levels of CO2 and its temporally variable nature, agricultural streams clearly need more attention in order to understand and incorporate these dynamics in large-scale extrapolations.
Quan Zhang, Huimin Lei, Dawen Yang, Lihua Xiong, Pan Liu, and Beijing Fang
Biogeosciences, 17, 2245–2262, https://doi.org/10.5194/bg-17-2245-2020, https://doi.org/10.5194/bg-17-2245-2020, 2020
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Research into climate change has been popular over the past few decades. Greenhouse gas emissions are found to be responsible for climate change. Among all the ecosystems, cropland is the main food source for mankind, therefore its carbon cycle and contribution to the global carbon balance interest us. Our evaluation of the typical wheat–maize rotation cropland over the North China Plain shows it is a net CO2 emission to the atmosphere and that emissions will continue to rise in the future.
Sheila Wachiye, Lutz Merbold, Timo Vesala, Janne Rinne, Matti Räsänen, Sonja Leitner, and Petri Pellikka
Biogeosciences, 17, 2149–2167, https://doi.org/10.5194/bg-17-2149-2020, https://doi.org/10.5194/bg-17-2149-2020, 2020
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Limited data on emissions in Africa translate into uncertainty during GHG budgeting. We studied annual CO2, N2O, and CH4 emissions in four land-use types in Kenyan savanna using static chambers and gas chromatography. CO2 emissions varied between seasons and land-use types. Soil moisture and vegetation explained the seasonal variation, while soil temperature was insignificant. N2O and CH4 emissions did not vary at all sites. Our results are useful in climate change mitigation interventions.
Roland Vernooij, Marcos Vinicius Giongo Alves, Marco Assis Borges, Máximo Menezes Costa, Ana Carolina Sena Barradas, and Guido R. van der Werf
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-86, https://doi.org/10.5194/bg-2020-86, 2020
Revised manuscript accepted for BG
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We used drones to measure greenhouse gas emission factors from fires in the Brazilian Cerrado.
We compared early dry season management fires and late dry season fires to determine if fire management can be a tool in abating emissions.
Although we found some evidence of increased CO and CH4 emission factors, the seasonal effect was smaller than in previous studies.
For N2O, the third most important greenhouse gas, we found opposite trends in grasses and shrub dominated areas.
Celina Burkholz, Neus Garcias-Bonet, and Carlos M. Duarte
Biogeosciences, 17, 1717–1730, https://doi.org/10.5194/bg-17-1717-2020, https://doi.org/10.5194/bg-17-1717-2020, 2020
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Seagrass meadows store carbon in their biomass and sediments, but they have also been shown to be sources of carbon dioxide (CO2) and methane (CH4). We experimentally investigated the effect of warming and prolonged darkness on CO2 and CH4 fluxes in Red Sea seagrass (Halophila stipulacea) communities. Our results indicated that sublethal warming may lead to increased emissions of greenhouse gases from seagrass meadows which may contribute to further enhance global warming.
Paula Alejandra Lamprea Pineda, Marijn Bauters, Hans Verbeeck, Selene Baez, Matti Barthel, and Pascal Boeckx
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-105, https://doi.org/10.5194/bg-2020-105, 2020
Revised manuscript accepted for BG
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Besides the well-known role of tropical forests for CO2 capture, their soils can also consume CH4 and emit N2O, a GHG 300 times stronger than CO2. In this study, we quantified the soil emission/consumption of CO2, CH4 and N2O of tropical forests located in the northern Ecuadorian Andes. We observed a net consumption of N2O at higher altitudes, indicating a probably unaccounted sink. Our results highlight the importance of tropical forests as a means of mitigation to curb global warming.
Chris R. Flechard, Andreas Ibrom, Ute M. Skiba, Wim de Vries, Marcel van Oijen, David R. Cameron, Nancy B. Dise, Janne F. J. Korhonen, Nina Buchmann, Arnaud Legout, David Simpson, Maria J. Sanz, Marc Aubinet, Denis Loustau, Leonardo Montagnani, Johan Neirynck, Ivan A. Janssens, Mari Pihlatie, Ralf Kiese, Jan Siemens, André-Jean Francez, Jürgen Augustin, Andrej Varlagin, Janusz Olejnik, Radosław Juszczak, Mika Aurela, Daniel Berveiller, Bogdan H. Chojnicki, Ulrich Dämmgen, Nicolas Delpierre, Vesna Djuricic, Julia Drewer, Eric Dufrêne, Werner Eugster, Yannick Fauvel, David Fowler, Arnoud Frumau, André Granier, Patrick Gross, Yannick Hamon, Carole Helfter, Arjan Hensen, László Horváth, Barbara Kitzler, Bart Kruijt, Werner L. Kutsch, Raquel Lobo-do-Vale, Annalea Lohila, Bernard Longdoz, Michal V. Marek, Giorgio Matteucci, Marta Mitosinkova, Virginie Moreaux, Albrecht Neftel, Jean-Marc Ourcival, Kim Pilegaard, Gabriel Pita, Francisco Sanz, Jan K. Schjoerring, Maria-Teresa Sebastià, Y. Sim Tang, Hilde Uggerud, Marek Urbaniak, Netty van Dijk, Timo Vesala, Sonja Vidic, Caroline Vincke, Tamás Weidinger, Sophie Zechmeister-Boltenstern, Klaus Butterbach-Bahl, Eiko Nemitz, and Mark A. Sutton
Biogeosciences, 17, 1583–1620, https://doi.org/10.5194/bg-17-1583-2020, https://doi.org/10.5194/bg-17-1583-2020, 2020
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Experimental evidence from a network of 40 monitoring sites in Europe suggests that atmospheric nitrogen deposition to forests and other semi-natural vegetation impacts the carbon sequestration rates in ecosystems, as well as the net greenhouse gas balance including other greenhouse gases such as nitrous oxide and methane. Excess nitrogen deposition in polluted areas also leads to other environmental impacts such as nitrogen leaching to groundwater and other pollutant gaseous emissions.
Chris R. Flechard, Marcel van Oijen, David R. Cameron, Wim de Vries, Andreas Ibrom, Nina Buchmann, Nancy B. Dise, Ivan A. Janssens, Johan Neirynck, Leonardo Montagnani, Andrej Varlagin, Denis Loustau, Arnaud Legout, Klaudia Ziemblińska, Marc Aubinet, Mika Aurela, Bogdan H. Chojnicki, Julia Drewer, Werner Eugster, André-Jean Francez, Radosław Juszczak, Barbara Kitzler, Werner L. Kutsch, Annalea Lohila, Bernard Longdoz, Giorgio Matteucci, Virginie Moreaux, Albrecht Neftel, Janusz Olejnik, Maria J. Sanz, Jan Siemens, Timo Vesala, Caroline Vincke, Eiko Nemitz, Sophie Zechmeister-Boltenstern, Klaus Butterbach-Bahl, Ute M. Skiba, and Mark A. Sutton
Biogeosciences, 17, 1621–1654, https://doi.org/10.5194/bg-17-1621-2020, https://doi.org/10.5194/bg-17-1621-2020, 2020
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Nitrogen deposition from the atmosphere to unfertilized terrestrial vegetation such as forests can increase carbon dioxide uptake and favour carbon sequestration by ecosystems. However the data from observational networks are difficult to interpret in terms of a carbon-to-nitrogen response, because there are a number of other confounding factors, such as climate, soil physical properties and fertility, and forest age. We propose a model-based method to untangle the different influences.
Pauline Sophie Rummel, Birgit Pfeiffer, Johanna Pausch, Reinhard Well, Dominik Schneider, and Klaus Dittert
Biogeosciences, 17, 1181–1198, https://doi.org/10.5194/bg-17-1181-2020, https://doi.org/10.5194/bg-17-1181-2020, 2020
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Chemical composition of plant litter controls C availability for biological N transformation processes in soil. In this study, we showed that easily degradable maize shoots stimulated microbial respiration and mineralization leading to high N2O formation in litter-associated hot spots. A higher share of slowly degradable C compounds and lower concentrations of water-soluble N restricted N2O emissions from maize roots. Bacterial community structure reflected degradability of maize litter.
Cynthia Soued and Yves T. Prairie
Biogeosciences, 17, 515–527, https://doi.org/10.5194/bg-17-515-2020, https://doi.org/10.5194/bg-17-515-2020, 2020
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Freshwater reservoirs emit greenhouse gases (GHGs) due to organic matter decay after landscape flooding. In order to better understand this phenomenon, we performed a comprehensive carbon footprint assessment of a tropical reservoir. Contrary to predictions, 89 % of measured emissions occurred downstream of the dam. Comparing predicted vs. measured emissions revealed weaknesses in our current modeling framework and insights to improve our ability to quantify and reduce reservoir GHG emissions.
Shimelis Gizachew Raji and Peter Dörsch
Biogeosciences, 17, 345–359, https://doi.org/10.5194/bg-17-345-2020, https://doi.org/10.5194/bg-17-345-2020, 2020
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Intercropping maize with forage legumes can benefit Ethiopian smallholder farmers by providing cheap nitrogen and valuable livestock feed. We measured N2O emissions and maize yields and found that high legume biomasses may enhance N2O emissions per unit of harvested maize but that, after mulching, legume N can partly replace expensive mineral N. Thus, legume intercropping can be a valid strategy in the framework of climate-smart agriculture in sub-Saharan Africa.
Arezoo Taghizadeh-Toosi, Lars Elsgaard, Tim J. Clough, Rodrigo Labouriau, Vibeke Ernstsen, and Søren O. Petersen
Biogeosciences, 16, 4555–4575, https://doi.org/10.5194/bg-16-4555-2019, https://doi.org/10.5194/bg-16-4555-2019, 2019
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Organic soils drained for crop production or grazing land have high potential for nitrous oxide emissions. The present study investigated the regulation of N2O emissions in a raised bog area drained for agriculture. It seems that archaeal ammonia oxidation and either chemodenitrification or nitrifier denitrification were considered to be plausible pathways of N2O production in spring, whereas in the autumn heterotrophic denitrification may have been more important at arable sites.
Hermann W. Bange, Chun Hock Sim, Daniel Bastian, Jennifer Kallert, Annette Kock, Aazani Mujahid, and Moritz Müller
Biogeosciences, 16, 4321–4335, https://doi.org/10.5194/bg-16-4321-2019, https://doi.org/10.5194/bg-16-4321-2019, 2019
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Nitrous oxide (N2O) and methane (CH4) are atmospheric trace gases which play important roles in the climate and atmospheric chemistry of the Earth. However, little is known about their emissions from rivers and estuaries. To this end, concentrations of N2O and CH4 were measured during a seasonal study in six rivers and estuaries in northwestern Borneo. The concentrations of both gases were mainly driven by rainfall. The rivers and estuaries were an overall net source of atmospheric N2O and CH4.
Jackie R. Webb, Peter R. Leavitt, Gavin L. Simpson, Helen M. Baulch, Heather A. Haig, Kyle R. Hodder, and Kerri Finlay
Biogeosciences, 16, 4211–4227, https://doi.org/10.5194/bg-16-4211-2019, https://doi.org/10.5194/bg-16-4211-2019, 2019
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Small farm reservoirs are key features within agricultural landscapes, yet these waterbodies can contribute substantial greenhouse gas (GHG) emissions to the atmosphere. This study assessed some of the environmental factors that may impact the production of these GHGs. We found promise that farm reservoirs can act as net greenhouse gas sinks and identified some of the key water quality, landscape, and design features that may support GHG mitigation.
Thomas Klintzsch, Gerald Langer, Gernot Nehrke, Anna Wieland, Katharina Lenhart, and Frank Keppler
Biogeosciences, 16, 4129–4144, https://doi.org/10.5194/bg-16-4129-2019, https://doi.org/10.5194/bg-16-4129-2019, 2019
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Marine algae might contribute to the observed methane oversaturation in oxic waters, but so far direct evidence for methane production by marine algae is limited. We investigated three widespread haptophytes for methane formation. Our results provide unambiguous evidence that all investigated marine algae produce methane per se and at substantial rates. We conclude that each of the three algae studied here could substantially account for the methane production observed in field studies.
Fabien Leroy, Sébastien Gogo, Christophe Guimbaud, Léonard Bernard-Jannin, Xiaole Yin, Guillaume Belot, Wang Shuguang, and Fatima Laggoun-Défarge
Biogeosciences, 16, 4085–4095, https://doi.org/10.5194/bg-16-4085-2019, https://doi.org/10.5194/bg-16-4085-2019, 2019
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This study demonstrates the implications of Molinia caerulea colonization in Sphagnum peatland on the C fluxes by enhancing the CO2 uptake by photosynthesis (but which led to higher CO2 and CH4 emissions) and also on the parameters controlling it (by increasing the temperature sensitivity of the CH4 emissions). Furthermore, roots and litter of Molinia caerulea could provide additional substrates for C emissions and should be taken into account in further works.
Xiao Ma, Sinikka T. Lennartz, and Hermann W. Bange
Biogeosciences, 16, 4097–4111, https://doi.org/10.5194/bg-16-4097-2019, https://doi.org/10.5194/bg-16-4097-2019, 2019
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Monthly measurements of nitrous oxide (N2O), a potent greenhouse gas and ozone depletion agent, were conducted at Boknis Eck (BE), a time series station in the southwestern Baltic Sea, since July 2005. Low N2O concentrations were observed in autumn and high in winter and early spring. Dissolved nutrients and oxygen played important roles in N2O distribution. Although we did not observe a significant N2O trend during 2005–2017, a decrease in N2O concentration and emission seems likely in future.
Eric J. Morgan, Jost V. Lavric, Damian L. Arévalo-Martínez, Hermann W. Bange, Tobias Steinhoff, Thomas Seifert, and Martin Heimann
Biogeosciences, 16, 4065–4084, https://doi.org/10.5194/bg-16-4065-2019, https://doi.org/10.5194/bg-16-4065-2019, 2019
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Taking a 2-year atmospheric record of atmospheric oxygen and the greenhouse gases N2O, CO2, and CH4, made at a coastal site in the Namib Desert, we estimated the fluxes of these gases from upwelling events in the northern Benguela Current region. We compared these results with flux measurements made on a research vessel in the study area at the same time and found that the two approaches agreed well. The study region was a source of N2O, CO2, and CH4 to the atmosphere during upwelling events.
Hubertus Fischer, Jochen Schmitt, Michael Bock, Barbara Seth, Fortunat Joos, Renato Spahni, Sebastian Lienert, Gianna Battaglia, Benjamin D. Stocker, Adrian Schilt, and Edward J. Brook
Biogeosciences, 16, 3997–4021, https://doi.org/10.5194/bg-16-3997-2019, https://doi.org/10.5194/bg-16-3997-2019, 2019
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N2O concentrations were subject to strong variations accompanying glacial–interglacial but also rapid climate changes over the last 21 kyr. The sources of these N2O changes can be identified by measuring the isotopic composition of N2O in ice cores and using the distinct isotopic composition of terrestrial and marine N2O. We show that both marine and terrestrial sources increased from the last glacial to the Holocene but that only terrestrial emissions responded quickly to rapid climate changes.
Alberto V. Borges, François Darchambeau, Thibault Lambert, Cédric Morana, George H. Allen, Ernest Tambwe, Alfred Toengaho Sembaito, Taylor Mambo, José Nlandu Wabakhangazi, Jean-Pierre Descy, Cristian R. Teodoru, and Steven Bouillon
Biogeosciences, 16, 3801–3834, https://doi.org/10.5194/bg-16-3801-2019, https://doi.org/10.5194/bg-16-3801-2019, 2019
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Tropical rivers might be strong sources of CO2 and CH4 to the atmosphere, although there is an enormous data gap. The origin of CO2 in lowland tropical rivers is not well characterized and can be from terra firme or from wetlands (flooded forests and aquatic macrophytes). We obtained a large field dataset of CO2, CH4 and N2O in the Congo, the second-largest river in the world, which allows us to quantity the emission of these greenhouse gases to the atmosphere and investigate their origin.
Mika Korkiakoski, Juha-Pekka Tuovinen, Timo Penttilä, Sakari Sarkkola, Paavo Ojanen, Kari Minkkinen, Juuso Rainne, Tuomas Laurila, and Annalea Lohila
Biogeosciences, 16, 3703–3723, https://doi.org/10.5194/bg-16-3703-2019, https://doi.org/10.5194/bg-16-3703-2019, 2019
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We measured greenhouse gas and energy fluxes for 2 years after clear-cutting in a peatland forest. We found high carbon dioxide and nitrous oxide emissions. However, in the second year after clear-cutting, the carbon dioxide emissions had already decreased by 33 % from the first year. Also, clear-cutting turned the site from a methane sink into a methane source. We conclude that clear-cutting peatland forests exerts a strong climatic warming effect through accelerated emission of greenhouse gas.
Kleiton R. de Araújo, Henrique O. Sawakuchi, Dailson J. Bertassoli Jr., André O. Sawakuchi, Karina D. da Silva, Thiago B. Vieira, Nicholas D. Ward, and Tatiana S. Pereira
Biogeosciences, 16, 3527–3542, https://doi.org/10.5194/bg-16-3527-2019, https://doi.org/10.5194/bg-16-3527-2019, 2019
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Run-of-the-river (ROR) reservoirs have reduced flooded areas that maintain natural river characteristics; however, little is known about their influence on carbon dioxide (CO2) emission. In this regard, we evaluated the spatiotemporal CO2 fluxes (FCO2) and partial CO2 pressure (pCO2) of the Belo Monte hydropower complex. Our results emphasize that ROR dams contribute to CO2) emissions. Only FCO2 varies through reservoirs; in addition, both FCO2 and pCO2 are spatially heterogeneous.
Lukas Kohl, Markku Koskinen, Kaisa Rissanen, Iikka Haikarainen, Tatu Polvinen, Heidi Hellén, and Mari Pihlatie
Biogeosciences, 16, 3319–3332, https://doi.org/10.5194/bg-16-3319-2019, https://doi.org/10.5194/bg-16-3319-2019, 2019
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Plants emit small amounts of methane and large amounts of volatile organic compounds (VOCs). Measurements of plant methane emissions therefore require analysers that can provide accurate measurements of CH4 concentrations in the presence of changing amounts of VOCs. We therefore quantified to which degree various VOCs bias methane concentration measurements on different analysers. Our results show that some analysers are more sensitive to the presence of VOCs than others.
Petri Kiuru, Anne Ojala, Ivan Mammarella, Jouni Heiskanen, Kukka-Maaria Erkkilä, Heli Miettinen, Timo Vesala, and Timo Huttula
Biogeosciences, 16, 3297–3317, https://doi.org/10.5194/bg-16-3297-2019, https://doi.org/10.5194/bg-16-3297-2019, 2019
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Many boreal lakes emit the greenhouse gas carbon dioxide (CO2) to the atmosphere. We incorporated four different gas exchange models into a physico-biochemical lake model and studied their ability to simulate lake air–water CO2 fluxes. The inclusion of refined gas exchange models in lake models that simulate carbon cycling is important to assess lake carbon budgets. However, higher estimates for inorganic carbon sources in boreal lakes are needed to balance the CO2 losses to the atmosphere.
Erkan Ibraim, Benjamin Wolf, Eliza Harris, Rainer Gasche, Jing Wei, Longfei Yu, Ralf Kiese, Sarah Eggleston, Klaus Butterbach-Bahl, Matthias Zeeman, Béla Tuzson, Lukas Emmenegger, Johan Six, Stephan Henne, and Joachim Mohn
Biogeosciences, 16, 3247–3266, https://doi.org/10.5194/bg-16-3247-2019, https://doi.org/10.5194/bg-16-3247-2019, 2019
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Nitrous oxide (N2O) is an important greenhouse gas and the major stratospheric ozone-depleting substance; therefore, mitigation of anthropogenic N2O emissions is needed. To trace N2O-emitting source processes, in this study, we observed N2O isotopocules above an intensively managed grassland research site with a recently developed laser spectroscopy method. Our results indicate that the domain of denitrification or nitrifier denitrification was the major N2O source.
Camilo Rey-Sanchez, Gil Bohrer, Julie Slater, Yueh-Fen Li, Roger Grau-Andrés, Yushan Hao, Virginia I. Rich, and G. Matt Davies
Biogeosciences, 16, 3207–3231, https://doi.org/10.5194/bg-16-3207-2019, https://doi.org/10.5194/bg-16-3207-2019, 2019
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It is estimated that natural wetlands emit approximately 30 % of all the methane released to the atmosphere; yet these estimates are highly uncertain due to the complexity of biological, chemical, and physical processes controlling methane emissions. In this study, we explore how some of these key processes drive methane emissions in a temperate peat bog. We show that the composition of microbial methane cyclers in the upper portion of the peat drives the velocity of methane release to the air.
Jocelyn E. Egan, David R. Bowling, and David A. Risk
Biogeosciences, 16, 3197–3205, https://doi.org/10.5194/bg-16-3197-2019, https://doi.org/10.5194/bg-16-3197-2019, 2019
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Traditionally a mass-dependent correction is made when measuring the radiocarbon composition in organic samples. This correction has not been evaluated for the soil gas environment where gas transport processes are important. Here, we show using theory that this traditional correction is not appropriate for estimating the radiocarbon composition of soil biological production. We also propose a new solution that accounts for soil gas transport processes.
Mathias Göckede, Fanny Kittler, and Carsten Schaller
Biogeosciences, 16, 3113–3131, https://doi.org/10.5194/bg-16-3113-2019, https://doi.org/10.5194/bg-16-3113-2019, 2019
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Methane is one of the most important greenhouse gases. Methane emissions from land sources to the atmosphere often occur in the form of short but intense outbursts, which are difficult to measure. We developed a new software tool based on wavelets which reliably quantifies such methane outbursts. Using these results as a reference, our study shows that regular data processing using the eddy-covariance technique provides solid long-term methane budgets, but short-term uncertainties can be high.
Robert W. Howarth
Biogeosciences, 16, 3033–3046, https://doi.org/10.5194/bg-16-3033-2019, https://doi.org/10.5194/bg-16-3033-2019, 2019
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Atmospheric methane has risen rapidly since 2008 and has become more depleted in 13C, in contrast to the trend towards more 13C enrichment in the late 20th century. Many have used this isotopic evidence to infer an increased biogenic source. Here I analyze the 13C trend with the consideration that methane from shale gas is somewhat depleted in 13C compared to other fossil fuels. I conclude that shale gas may be responsible for a third of the global increase from all sources.
Sissel Hansen, Randi Berland Frøseth, Maria Stenberg, Jarosław Stalenga, Jørgen E. Olesen, Maike Krauss, Paweł Radzikowski, Jordi Doltra, Shahid Nadeem, Torfinn Torp, Valentini Pappa, and Christine A. Watson
Biogeosciences, 16, 2795–2819, https://doi.org/10.5194/bg-16-2795-2019, https://doi.org/10.5194/bg-16-2795-2019, 2019
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We discuss nitrous oxide (N2O) emissions and nitrate leaching in organic arable farming, and potential mitigation strategies. The losses are low under growing crops, but crop residues may induce larger losses. The correlation between yearly total N-input and N2O emissions is weak. Cover crops, except sole legumes, have the potential to reduce nitrate leaching but may enhance N2O emissions. Optimised synchrony of mineralisation with crop N uptake will enhance crop productivity and reduce losses.
Scott J. Davidson, Christine Van Beest, Richard Petrone, and Maria Strack
Biogeosciences, 16, 2651–2660, https://doi.org/10.5194/bg-16-2651-2019, https://doi.org/10.5194/bg-16-2651-2019, 2019
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Boreal peatlands represent an important store of carbon and wildfire can have a significant impact on carbon exchange. We assessed the impact of fire on methane (CH4) emissions using both a field and laboratory study. We found that fire switched the typical understanding of peatland CH4 emissions, burned sites having significantly reduced emissions (likely due to reduction in organic matter for CH4 production) and no relationship with water table, unlike at the unburned site.
Norman Rößger, Christian Wille, David Holl, Mathias Göckede, and Lars Kutzbach
Biogeosciences, 16, 2591–2615, https://doi.org/10.5194/bg-16-2591-2019, https://doi.org/10.5194/bg-16-2591-2019, 2019
Lin Lin, Xixi Lu, Shaoda Liu, Shie-Yui Liong, and Kaidao Fu
Biogeosciences, 16, 2205–2219, https://doi.org/10.5194/bg-16-2205-2019, https://doi.org/10.5194/bg-16-2205-2019, 2019
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Damming did not significantly increase carbon dioxide emissions from the reservoir surface, as shown in a case study in a reservoir constrained within the narrow upper Mekong River valley. This finding might provide some evidence to the green credits for hydropower in China. One-year monitoring of carbon dioxide emissions from the water surface found that the higher emissions were concentrated at the riverine inlets in winter and more related to the mixing process of inflow and reservoir water.
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