Preprints
https://doi.org/10.5194/essd-2025-585
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/essd-2025-585
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
20 Oct 2025
| 20 Oct 2025
Status: this preprint is currently under review for the journal ESSD.
ABCFlux v2: Arctic–boreal CO2 and CH4 monthly flux observations and ancillary information across terrestrial and freshwater ecosystems
Abstract. Measurements of surface-atmosphere carbon dioxide (CO2) and methane (CH4) fluxes have been relatively sparse across the Arctic tundra and boreal biomes, causing significant uncertainties in carbon budget estimates from the region. While the availability of Arctic-boreal carbon flux data has increased substantially over the past decade, the data have remained spread across different repositories, scientific articles, and unpublished sources, making it difficult to leverage. Here we present a new dataset of monthly Arctic-boreal carbon fluxes (ABCFlux v2) across terrestrial (wetlands and uplands) and freshwater (lakes and rivers) ecosystems compiled from previous syntheses including the Arctic-boreal CO2 flux database (ABCFlux v1), the Boreal-Arctic Wetland and Lake Methane Dataset (BAWLD-CH4), and the Global River Methane Database (GRiMeDB). In addition, we consider data from general-purpose (e.g., Zenodo) and flux network repositories, literature, and site principal investigators. The dataset includes surface-atmosphere CO2 fluxes of gross primary production (GPP), ecosystem respiration (Reco), and net ecosystem exchange (NEE), alongside CH4 fluxes. For aquatic ecosystems, we split CH4 fluxes into diffusive and ebullitive flux pathways, and included potential emissions from transient storage in the water column (“storage fluxes”), alongside CO2 and CH4 concentrations dissolved in the surface water. Fluxes are measured through a variety of methods including chamber and eddy covariance techniques alongside bubble traps, ice-surveys, and concentration-based turbulence-driven modelling in aquatic ecosystems. The monthly flux data are reported together with supporting methodological and environmental metadata. The resulting ABCFlux v2 has 23,656 flux site-months, 8,182 concentration site-months, and 199 seasonal observations from 1,024 sites, and includes 55,560 reported fluxes (i.e. sum of GPP, Reco, NEE, and CH4 fluxes) from the years 1984 to 2024. The majority of monthly observations occurred after 1999. Wetlands had the highest number of site-month observations (8,641), followed by boreal forest (6,981), lotic ecosystems (6,275), lentic ecosystems (3,725) and upland tundra (3,308). Measurements of CO2 dominated the dataset across most ecosystem types (25,101) except for lentic ecosystems, where CH4 flux site-months (3,024) were more frequent than CO2 flux site-months (2,858). Overall, ABCFlux v2 includes 158 % more site-months for terrestrial CO2 flux data compared to ABCFlux v1. Integrating and updating BAWLD-CH4 flux data from growing season averages to monthly fluxes resulted in 5,671 site-months of chamber CH4 data compared to 762 site-years. This collaborative initiative, involving contributions from over 260 researchers, provides a comprehensive overview of the current state of the Arctic-boreal carbon flux network and its data, and serves as an important step in reducing uncertainties in Arctic-boreal carbon budgets and in enhancing our understanding of climate feedbacks. The data can be accessed at ORNL DAAC at https://doi.org/10.3334/ORNLDAAC/2448 (Virkkala et al., 2025b).
How to cite. Virkkala, A.-M., Wargowsky, I., Vogt, J., Kuhn, M. A., Madaan, S., O'Keefe, R., Windholz, T., Arndt, K. A., Rogers, B. M., Watts, J. D., Kent, K., Göckede, M., Olefeldt, D., Rocher-Ros, G., Schuur, E. A. G., Bastviken, D., Aalstad, K., Aho, K., Ala-Könni, J., Alcock, H., Althuizen, I., Arp, C. D., Asanuma, J., Attermeyer, K., Aurela, M., Balathandayuthabani, S., Barr, A., Barret, M., Batkhishig, O., Biasi, C., Björkman, M. P., Black, A., Blanc-Betes, E., Bodmer, P., Boike, J., Bolek, A., Bouchard, F., Bussmann, I., Cabrol, L., Canfora, E., Carey, S., Castro-Morales, K., Chae, N., Christen, A., Christensen, T. R., Christiansen, C. T., Chu, H., Clark, G., Clayer, F., Crill, P., Cunada, C., Davidson, S. J., Dean, J. F., Dengel, S., Detto, M., Dieleman, C., Domine, F., Dyukarev, E., Edgar, C., Elberling, B., Emmerton, C. A., Euskirchen, E., Falvo, G., Friborg, T., Garneau, M., Giamberini, M., Glagolev, M. V., Gonzalez-Meler, M. A., Granath, G., Guðmundsson, J., Happonen, K., Harazono, Y., Harris, L., Hashemi, J., Hasson, N., Heerah, J., Heffernan, L., Helbig, M., Helgason, W., Heliasz, M., Henry, G., Hensgens, G., Hiyama, T., Hock, M., Holl, D., Holmes, B., Holst, J., Holst, T., Hould-Gosselin, G., Humphreys, E., Hung, J., Huotari, J., Ikawa, H., Ilyasov, D. V., Ishikawa, M., Iwahana, G., Iwata, H., Jackowicz-Korczynski, M. A., Jansen, J., Järveoja, J., Jassey, V. E. J., Jensen, R., Jentzsch, K., Jespersen, R. G., Johannesson, C.-F., Jones, C. P., Jonsson, A., Jung, J. Y., Juutinen, S., Kane, E., Karlsson, J., Karsanaev, S., Kasak, K., Kelly, J., Kempton, K., Klaus, M., Kling, G. W., Kljun, N., Knutson, J., Kobayashi, H., Kochendorfer, J., Kohonen, K.-M., Kolari, P., Korkiakoski, M., Korrensalo, A., Kortelainen, P., Koster, E., Koster, K., Kotani, A., Krishnan, P., Kurbatova, J., Kutzbach, L., Kwon, M. J., Kyzivat, E. D., Lagroix, J., Langhorst, T., Lapshina, E., Larmola, T., Larsen, K. S., Laurion, I., Ledman, J., Lee, H., Leffler, A. J., Lesack, L., Lindroth, A., Lipson, D., Lohila, A., López-Blanco, E., St. Louis, V. L., Lundin, E., Luoto, M., Machimura, T., Magnani, M., Malhotra, A., Maljanen, M., Mammarella, I., Männistö, E., Marchesini, L. B., Marsh, P., Martkainen, P. J., Marushchak, M. E., Mastepanov, M., Mavrovic, A., Maximov, T., Minions, C., Montemayor, M., Morishita, T., Murphy, P., Nadeau, D. F., Nicholls, E., Nilsson, M. B., Niyazova, A., Nordén, J., Noumonvi, K. D., Nykanen, H., Oechel, W., Ojala, A., Okadera, T., Pal, S., Panov, A. V., Papakyriakou, T., Papale, D., Park, S.-J., Parmentier, F.-J. W., Pastorello, G., Peacock, M., Peichl, M., Petrov, R., St. Pierre, K., Pirk, N., Plein, J., Preskienis, V., Prokushkin, A., Pumpanen, J., Rains, H. A., Rakos, N., Räsänen, A., Rautakoski, H., Rinnan, R., Rinne, J., Rocha, A., Roulet, N., Roy, A., Rutgersson, A., Sabrekov, A. F., Sachs, T., Sahlée, E., Salazar, A., Sawakuchi, H. O., Schulze, C., Seco, R., Sepulveda-Jauregui, A., Serikova, S., Serrone, A., Silvennoinen, H. M., Sjogersten, S., Skeeter, J., Snöälv, J., Sobek, S., Sonnentag, O., Stanley, E. H., Strack, M., Strom, L., Sullivan, P., Sullivan, R., Sytiuk, A., Tagesson, T., Taillardat, P., Talbot, J., Tank, S. E., Tenuta, M., Terenteva, I., Thalasso, F., Thiboult, A., Thorgeirsson, H., Garcia Tigreros, F., Torn, M., Townsend-Small, A., Treat, C., Tremblay, A., Trotta, C., Tuittila, E.-S., Turetsky, M., Ueyama, M., Umair, M., Vähä, A., van Delden, L., van Hardenbroek, M., Varlagin, A., Varner, R. K., Veretennikova, E., Vesala, T., Virtanen, T., Voigt, C., Vonk, J. E., Wagner, R., Walter Anthony, K., Wang, Q., Watanabe, M., Webb, H., Welker, J. M., Westergaard-Nielsen, A., Westermann, S., White, J. R., Wille, C., Williamson, S. N., Zolkos, S., Zona, D., and Natali, S. M.: ABCFlux v2: Arctic–boreal CO2 and CH4 monthly flux observations and ancillary information across terrestrial and freshwater ecosystems, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2025-585, in review, 2025.
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General Comments
Following on the release of ABCFlux v1, this v2 dataset is generally an improvement to v1 in every way. An increased amount of data has been included in this new release, covering more years of data, aquatic sites with substantial corresponding flux data, as well as CH4 data. The scope of the dataset is impressive, as is the work that has gone into curating, filtering, and aggregation of the data. Additionally, substantial effort has been spent to document and summarize the dataset, the processing behind it, and all the associated ancillary data and metadata - a commendable accomplishment. This is indeed necessary for such a large, disparate dataset that includes such a substantial number of sources and workflows, and is critical to prepare the data to be used as a single product for Arctic and Boreal ecosystem analysis, the intention the authors have. Particularly improved from v1 is the move to standardize the temporal interval to a consistent time step for analysis, though by their own admission, not all sites have consistent time series data due to screening or lack of data, something that would be invaluable to assess fluxes over growing seasons. Still, having data at standardized time intervals allows this dataset to be further used by researchers interested in analyzing coincident data sources. Additionally, the improvement of land status and vegetation detail in this dataset will further benefit terrestrial researchers interested in community composition connected to fluxes.
While this dataset is incredibly valuable given its scale and breadth, one still wishes for a similar dataset with higher flux resolution with a similar level of screening and unified processing. Additionally, while the value of this dataset is its compilation consistency allowing for cohesive analysis, resources do exist that offer options for viewing and assessing the amount of flux data available globally as well as within specific domains in raw forms.
Specific Comments
- The ARGO data tool mentioned on line 1171 is a great resource for viewing and accessing Arctic and Boreal flux datasets. The value of the ABCFlux v2 dataset is the processing, screening, and cleaning that has gone into homogenizing all these diverse data sources. The ARGO data tool references ABCFlux v1. It would be great if the current version of this dataset could synergize more directly with that.
- It is clear from the detail in this paper that a significant amount of time has been spent listing and assessing all the harmonization efforts and where discrepancies exist. I found that I was sometimes reading similar details throughout the document, and at times would lose track of which section I was intended to be in. With the massive amount of detail that needs to be conveyed, I am not sure the best way to streamline this aside from making the authors aware of it. An example would be “For sites without monthly aggregated fluxes available, we present the fluxes as seasonal values and provide the start and end date of the measurement period.” (Line 497) This was approximately said on line 458 and feels redundant here. Could it be combined or streamlined?
- The location of these flux measurements (specifically tower data) is described in table 3 on line 643 as being as detailed as possible. Historically, one issue with flux tower location estimations has been the precision of the tower location, sometimes being off by 10s to 100s of meters (I should say in the cursory analysis of a few plots in this dataset, all plots seemed to generally line up well with the towers). Still, for some of these community datasets, potential offsets make alignment for cross-analysis with other data sources difficult, including scaled community composition and site specific data from other sources, which in harsh environments like the Arctic can turn over quickly. One benefit to this dataset would be a more precise alignment of these points with overall harmonization, though that shouldn't be a constraint on publication, just a suggestion.
- I really like the map style (Figure 1, line 475), but the sheer amount of data contained in them in v2 makes it hard to get a clear picture of where data is and how much exists. The zoomed in versions in the supplement are much clearer, but they only cover a few areas. Areas within Canada, particularly around the BERMS site, are hard to decipher. It would be great to have higher resolution maps for all major plot regions. Also, the map appears to be tilted where v1 seemed more north NADIR. The v1 version was a bit more legible. Additionally, on line 1350 you said “Moreover, the studied sites are heavily clustered in a few regions in Alaska and Fennoscandia, therefore leaving significant spatial gaps in coverage in spite of the relatively high absolute number of locations. In particular, despite Russia’s large land mass (close to 60% of the domain), data from Russia only comprise 10.8% of the dataset in terms of site-months and 15.3% of sites in ABCFlux v2 (with similar representativeness among terrestrial and aquatic data), making this region a critical data gap.” This makes sense, but I wouldn't let this be the reason to not render maps for all plots.
- The data is listed as Terrestrial and Aquatic in Figure 2 (line 479). The data repositories are listed twice, and NEON is listed on the bottom box but not the top (I realize AmeriFlux would contain NEON data). Some figures have terrestrial or aquatic in parentheses, but others don't, and it's hard to know then what is what. I would suggest improving the terrestrial/aquatic separation. Also, is the community contributed data intended to be in the middle covering both?
- I found expert_flags very valuable and informative (line 900).
Citation: https://doi.org/10.5194/essd-2025-585-RC1
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ABCFlux v2: Arctic–Boreal CO2 and CH4 In-situ Flux and Environmental Data A.-M. Virkkala et al. https://doi.org/10.3334/ORNLDAAC/2448
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Anna-Maria Virkkala
CORRESPONDING AUTHOR
Woodwell Climate Research Center, Falmouth, MA, USA
Isabel Wargowsky
Woodwell Climate Research Center, Falmouth, MA, USA
Judith Vogt
Max Planck Institute for Biogeochemistry, Jena, Germany
McKenzie A. Kuhn
Department of Geography, University of British Columbia, Vancouver, Canada
Woodwell Climate Research Center, Falmouth, MA, USA
Simran Madaan
Max Planck Institute for Biogeochemistry, Jena, Germany
Richard O'Keefe
Woodwell Climate Research Center, Falmouth, MA, USA
Tiffany Windholz
Woodwell Climate Research Center, Falmouth, MA, USA
Kyle A. Arndt
Woodwell Climate Research Center, Falmouth, MA, USA
Brendan M. Rogers
Woodwell Climate Research Center, Falmouth, MA, USA
Jennifer D. Watts
Woodwell Climate Research Center, Falmouth, MA, USA
Kelcy Kent
Woodwell Climate Research Center, Falmouth, MA, USA
Mathias Göckede
Max Planck Institute for Biogeochemistry, Jena, Germany
David Olefeldt
Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
Gerard Rocher-Ros
Department of Ecology, Environment and Geoscience, Umeå University, Umeå, Sweden
Edward A. G. Schuur
Center for Ecosystem Science and Society, Northern Arizona University, USA
David Bastviken
Department of Thematic Studies-Environmental Change, Linköping University, Linköping, Sweden
Kristoffer Aalstad
Department of Geosciences, University of Oslo, Oslo, Norway
Kelly Aho
Department of Biology, Boston University, USA
Joonatan Ala-Könni
Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Finland
Haley Alcock
Department of Geography, Université de Montréal, QC, Canada
Inge Althuizen
NORCE Norwegian Research Centre and Bjerknes Centre for Climate Research, Bergen, Norway
Christopher D. Arp
Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK, USA
Jun Asanuma
University of Tsukuba, Tsukuba, Japan
Katrin Attermeyer
Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, 1030 Vienna, Austria
WasserCluster Lunz, Biologische Station, Dr. Carl Kupelwieser Promenade 5, 3293 Lunz am See, Austria
Mika Aurela
Finnish Meteorological Institute, Climate System Research, Finland
Sivakiruthika Balathandayuthabani
Department of Thematic Studies-Environmental Change, Linköping University, Linköping, Sweden
Tamil Nadu Agricultural University, Coimbatore, India
Alan Barr
Global Institute for Water Security, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Maialen Barret
Laboratoire d’Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
Ochirbat Batkhishig
Institute of Geography and Geoecology, Mongolian Academy of Sciences, Ulaanbaatar, Mongolia
Christina Biasi
Department of Ecology, University of Innsbruck, Innsbruck, Austria
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
Mats P. Björkman
Department of Biology and Environmental Sciences, University of Gothenburg, Box 463, SE-40530 Gothenburg, Sweden
Gothenburg Global Biodiversity Centre, Box 463, SE-405 30 Gothenburg, Sweden
Andrew Black
Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, Canada
Elena Blanc-Betes
Institute for Sustainability, Energy, and Environment, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
Pascal Bodmer
Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA
Julia Boike
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Humboldt University of Berlin, Germany
Abdullah Bolek
Max Planck Institute for Biogeochemistry, Jena, Germany
Frédéric Bouchard
Centre d’études nordiques (CEN), Université Laval, Québec, Canada
Department of Applied Geomatics, Université de Sherbrooke, Sherbrooke, Canada
Ingeborg Bussmann
Department Shelf Sea System Ecology, Alfred Wegener Institute, Helgoland, Germany
Lea Cabrol
Aix-Marseille University, University Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (M.I.O.) Marseille, France
Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Santiago 7800003, Chile
Eleonora Canfora
CMCC Foundation - Euro-Mediterranean Center on Climate Change, Italy
Sean Carey
School of Earth, Environment and Society, McMaster University
Karel Castro-Morales
Friedrich Schiller University Jena, Jena, Germany
Namyi Chae
Institute of Life Science and Natural Resources, Korea University, Seoul, Republic of Korea
Andres Christen
Environmental Meteorology, Faculty of Environment and Natural Resources, University of Freiburg, Germany
Torben R. Christensen
Department of Ecoscience, Aarhus University, Denmark
Water, energy and environmental engineering research unit, Oulu University, Finland
Casper T. Christiansen
Department of Biology, University of Copenhagen, Denmark
Housen Chu
Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, USA
Graham Clark
Department of Earth and Environmental Sciences, St. Francis Xavier University, Antigonish, Canada
Francois Clayer
Norwegian Institute for Water Research (NIVA), Oslo, Norway
Patrick Crill
Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Sweden
Christopher Cunada
Government of the Northwest Territories, Canada
Scott J. Davidson
Department of Ecological, Plant and Animal Sciences, La Trobe University, Albury/Wodonga, VIC, Australia
Département des sciences biologiques, Université du Québec à Montréal, Montréal, Canada
Joshua F. Dean
School of Geographical Sciences, University of Bristol, Bristol, United Kingdom
Sigrid Dengel
Lawrence Berkeley National Laboratory, USA
Matteo Detto
High Meadows Environmental Institute, Princeton University, USA
Catherine Dieleman
School of Environmental Sciences, University of Guelph, Canada
Florent Domine
Takuvik Joint International Laboratory, Université Laval (Canada) and CNRS-INSU (France), Québec City, Canada
Egor Dyukarev
Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch of the Russian Academy of Sciences, Russia
Yugra State University, Russia
Colin Edgar
Institute of Arctic Biology, University of Alaska Fairbanks, USA
Bo Elberling
Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
Craig A. Emmerton
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
Eugenie Euskirchen
Institute of Arctic Biology, University of Alaska Fairbanks, USA
Grant Falvo
Center for Ecosystem Science and Society, Northern Arizona University, USA
Thomas Friborg
Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
Michelle Garneau
Geotop, Université du Québec à Montréal, Montréal, QC, Canada
Mariasilvia Giamberini
Institute of Geosciences and Earth Resources, National Research Council (CNR-IGG), 56124, Pisa, Italy
Mikhail V. Glagolev
Faculty of Soil Science, Lomonosov Moscow State University, building 12, Leninskie Gory, GSP-1, 119991, Moscow, Russia
Institute of Forest Science, Russian Academy of Sciences, 21 Sovetskaya st., Uspenskoe, Moscow region 143030, Russia
Miquel A. Gonzalez-Meler
Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
Gustaf Granath
Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
Jón Guðmundsson
Faculty of Environmental and Forest Sciences, Agricultural University of Iceland, Iceland
Konsta Happonen
Finnish Youth Research Society, Finland
Yoshinobu Harazono
International Arctic Research Center, University of Alaska Fairbanks, USA
Lorna Harris
Independent Researcher
Josh Hashemi
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Nicholas Hasson
University of Alaska Fairbanks, Fairbanks, Alaska, USA
Janna Heerah
Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
Liam Heffernan
Department of Earth Sciences, Vrije Universiteit, Amsterdam, Netherlands
Manuel Helbig
Department of Physics and Atmospheric Science, Dalhousie University, Halifax, NS, Canada
GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
Warren Helgason
Chemical and Biological Engineering, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
Michal Heliasz
Centre for Environmental and Climate Science, Lund University, Sweden
Greg Henry
Department of Geography, University of British Columbia, Vancouver, Canada
Geert Hensgens
Arctic Geology, University Centre in Svalbard, Svalbard, Norway
Department of Earth Sciences, Vrije Universiteit, Amsterdam, Netherlands
Tetsuya Hiyama
Institute for Space-Earth Environmental Research, Nagoya University, Japan
Macall Hock
Department of Biology, SDSU, San Diego, CA, USA
University of California Davis, USA
David Holl
Institute of Soil Science, Center for Earth System Research and Sustainability (CEN), Universität Hamburg, Hamburg, Germany
Beth Holmes
Department of Earth, Ocean, and Atmospheric Science, Florida State University, USA
Jutta Holst
Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
Thomas Holst
Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
Gabriel Hould-Gosselin
Department of Geography, Université de Montréal, QC, Canada
Elyn Humphreys
Department of Geography & Environmental Studies, Carleton University, Ottawa, Canada
Jacqueline Hung
Woodwell Climate Research Center, Falmouth, MA, USA
Jussi Huotari
Faculty of Biological and Environmental Sciences, Ecosystems and Environment Research Programme, Lammi Biological Station, University of Helsinki, Lammi FI-16900, Finland
Masinotek Oy, Ensimmäinen Savu 2, Vantaa FI-01510, Finland
Hiroki Ikawa
National Agriculture and Food Research Organization, Japan
Danil V. Ilyasov
UNESCO Department "Environmental Dynamics and Global Climate Changes", Yugra State University, Khanty-Mansiysk, Russia
Mamoru Ishikawa
Faculty of Earth Environmental Science, Hokkaido University, Japan
Go Iwahana
Arctic Research Center, Hokkaido University, Japan
International Arctic Research Center, University of Alaska Fairbanks, USA
Hiroki Iwata
Department of Environmental Science, Shinshu University, Matsumoto, Japan
Institute for Mountain Science, Shinshu University, Matsumoto, Japan
Marcin Antoni Jackowicz-Korczynski
Department of Ecoscience and Arctic Research Centre, Aarhus University, Roskilde, Denmark
Joachim Jansen
Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Finland
Järvi Järveoja
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
Vincent E. J. Jassey
Universite de Toulouse, Toulouse INP, CNRS, IRD, CRBE, Toulouse, France
Rasmus Jensen
Department of Ecoscience, Aarhus University, Denmark
Katharina Jentzsch
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Robert G. Jespersen
United States Forest Service, University of Alaska Anchorage, USA
Carl-Fredrik Johannesson
Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
Norwegian Institute for Nature Research (NINA), Oslo, Norway
Chersity P. Jones
Department of Earth Sciences and Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH
Anders Jonsson
Department of Ecology, Environment and Geoscience, Umeå University, Umeå, Sweden
Ji Young Jung
Korea Polar Research Institute, Incheon, South Korea
Sari Juutinen
Finnish Meteorological Institute, Finland
Evan Kane
College of Forest Resources and Environmental Science, Michigan Technological University, USA
Jan Karlsson
Department of Ecology, Environment and Geoscience, Umeå University, Umeå, Sweden
Sergey Karsanaev
Institute for Biological Problems of Cryolithozone of the Siberian Branch of the RAS - Division of Federal Research Centre "The Yakut Scientific Centre of the Siberian Branch of the Russian Academy of Sciences", Russia
Kuno Kasak
Department of Geography, University of Tartu, Estonia
Julia Kelly
Centre for Environmental and Climate Science, Lund University, Sweden
Kasha Kempton
Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
Marcus Klaus
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
George W. Kling
Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, USA
Natacha Kljun
Centre for Environmental and Climate Science, Lund University, Sweden
Jacqueline Knutson
Norwegian Institute for Water Research (NIVA), Oslo, Norway
Hideki Kobayashi
Japan Agency for Marine-Earth Science and Technology, Japan
John Kochendorfer
NOAA Air Resources Laboratory, Atmospheric Turbulence and Diffusion Division, Oak Ridge, TN 37830, USA
Kukka-Maaria Kohonen
Department of Environmental Systems Science, Institute for Agricultural Sciences, ETH Zurich, Zurich, Switzerland
Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Finland
Pasi Kolari
University of Helsinki, Finland
Mika Korkiakoski
Finnish Meteorological Institute, Climate System Research, Finland
Aino Korrensalo
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
Natural Resources Institute Finland, Natural Resources Unit, Joensuu, Finland
Pirkko Kortelainen
Finnish Environment Institute, Finland
Egle Koster
Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
Kajar Koster
Department of Environmental and Biological Sciences, University of Eastern Finland, Joensuu, Finland
Ayumi Kotani
Graduate School of Bioagricultural Sciences, Nagoya University, Japan
Praveena Krishnan
NOAA Air Resources Laboratory, Atmospheric Turbulence and Diffusion Division, Oak Ridge, TN 37830, USA
Juliya Kurbatova
A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
Lars Kutzbach
Institute of Soil Science, Center for Earth System Research and Sustainability (CEN), Universität Hamburg, Hamburg, Germany
Min Jung Kwon
Institute of Soil Science, Universität Hamburg, Hamburg, Germany
Korea Polar Research Institute, Incheon, South Korea
Ethan D. Kyzivat
Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, USA
Jessica Lagroix
University of Alberta, Canada
Theodore Langhorst
University of Massachusetts Amherst, USA
Elena Lapshina
UNESCO Department "Environmental Dynamics and Global Climate Changes", Yugra State University, Khanty-Mansiysk, Russia
Tuula Larmola
Natural Resources Institute Finland, Helsinki, Finland
Klaus S. Larsen
Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
Isabelle Laurion
Centre Eau Terre Environnement, Institut national de la recherche scientifique, Canada
Centre d’études nordiques (CEN), Université Laval, Québec, Canada
Justin Ledman
Center for Ecosystem Science and Society, Northern Arizona University, USA
Hanna Lee
Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
A. Joshua Leffler
Department of Natural Resource Management, South Dakota State University, Brookings, SD 57007, USA
Lance Lesack
Departments of Geography and Biological Sciences, Simon Fraser University, Canada
Anders Lindroth
Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
David Lipson
Department of Biology, SDSU, San Diego, CA, USA
Annalea Lohila
Finnish Meteorological Institute, Climate System Research, Finland
Efrén López-Blanco
Department of Ecoscience and Arctic Research Centre, Aarhus University, Roskilde, Denmark
Department of Environment and Minerals, Greenland Institute of Natural Resources, Nuuk, Greenland
Vincent L. St. Louis
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
Erik Lundin
Abisko Scientific Research Station, Swedish Polar Research Secretariat, Sweden
Misha Luoto
Department of Geosciences and Geography, University of Helsinki, Finland
Takashi Machimura
Graduate School of Engineering, The University of Osaka, Japan
Marta Magnani
Institute of Geosciences and Earth Resources, National Research Council (CNR-IGG), 10125 Torino, Italy
Avni Malhotra
Biological Sciences Division, Pacific Northwest National Laboratory, USA
Marja Maljanen
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
Ivan Mammarella
Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Finland
Elisa Männistö
Peatland and Soil Ecology Research Group, School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
Luca Belelli Marchesini
Forest Ecology Unit, Research and Innovation Centre, Edmund Mach Foundation, Italy
Phil Marsh
Wilfred Laurier University, Canada
Pertti J. Martkainen
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
Maija E. Marushchak
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
Mikhail Mastepanov
Department of Ecoscience and Arctic Research Centre, Aarhus University, Roskilde, Denmark
Oulanka Research Station, University of Oulu, Kuusamo, Finland
Alex Mavrovic
Cegep de Sherbrooke, Canada
Centre d’études nordiques (CEN), Université Laval, Québec, Canada
Universite du Quebec a Trois-Rivieres, Research Centre for Watershed-Aquatic ecosystem interactions (RIVE) , Canada
Trofim Maximov
Institute for Biological Problems of Cryolithozone of the Siberian Branch of the RAS - Division of Federal Research Centre "The Yakut Scientific Centre of the Siberian Branch of the Russian Academy of Sciences", Russia
Christina Minions
Woodwell Climate Research Center, Falmouth, MA, USA
Marco Montemayor
Woodwell Climate Research Center, Falmouth, MA, USA
Tomoaki Morishita
Forestry and Forest Products Research Institute, Tohoku Research Center, Japan
Patrick Murphy
Woodwell Climate Research Center, Falmouth, MA, USA
Daniel F. Nadeau
Department of Civil and Water Engineering, Universite Laval, QC, Canada
Erin Nicholls
Department of Earth, Energy and Environment, University of Calgary, Canada
Mats B. Nilsson
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
Anastasia Niyazova
UNESCO Department "Environmental Dynamics and Global Climate Changes", Yugra State University, Khanty-Mansiysk, Russia
Jenni Nordén
Norwegian Institute for Nature Research (NINA), Oslo, Norway
Koffi Dodji Noumonvi
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
Hannu Nykanen
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
Walter Oechel
Department of Biology, SDSU, San Diego, CA, USA
Anne Ojala
Natural Resources Institute Finland, Helsinki, Finland
Tomohiro Okadera
National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
Sujan Pal
Environmental Science Division, Argonne National Laboratory, Lemont, IL, USA
Alexey V. Panov
V. N. Sukachev Institute of forest, Siberian Branch of the Russian Academy of Sciences, Russia
Tim Papakyriakou
Centre for Earth Observation Science, University of Manitoba, MB, Canada
Dario Papale
National Research Council (CNR) - IRET, Monterotondo Scalo, Italy
Sang-Jong Park
Korea Polar Research Institute, Incheon, South Korea
Frans-Jan W. Parmentier
Center for Biogeochemistry of the Anthropocene, Department of Geosciences, University of Oslo, Oslo, Norway
Gilberto Pastorello
Scientific Data Division, Lawrence Berkeley National Laboratory, USA
Mike Peacock
Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden
Department of Geography and Planning, School of Environmental Sciences, University of Liverpool, Liverpool, UK
Matthias Peichl
Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå, Sweden
Roman Petrov
Institute for Biological Problems of Cryolithozone of the Siberian Branch of the RAS - Division of Federal Research Centre "The Yakut Scientific Centre of the Siberian Branch of the Russian Academy of Sciences", Russia
Kyra St. Pierre
Department of Earth and Environmental Sciences, University of Ottawa, Ottawa ON Canada, K1N 6N5, Canada
Norbert Pirk
Department of Geosciences, University of Oslo, Oslo, Norway
Jessica Plein
Department of Biology, SDSU, San Diego, CA, USA
Vilmantas Preskienis
Centre Eau Terre Environnement, Institut national de la recherche scientifique, Canada
Centre d’études nordiques (CEN), Université Laval, Québec, Canada
Departement des sciences fondamentales, Universite du Quebec a Chicoutimi, Saguenay, Canada
Groupe de recherche interuniversitaire en limnologie (GRIL), Quebec, Canada
Anatoly Prokushkin
V. N. Sukachev Institute of forest, Siberian Branch of the Russian Academy of Sciences, Russia
Jukka Pumpanen
Department of Environmental and Biological Sciences, University of Eastern Finland, Kuopio, Finland
Hilary A. Rains
PG Environmental, Fairfax, Virginia, USA
Niklas Rakos
Abisko Scientific Research Station, Swedish Polar Research Secretariat, Sweden
Aleski Räsänen
Geography Research Unit, University of Oulu, Oulu, Finland
Helena Rautakoski
Finnish Meteorological Institute, Finland
Riika Rinnan
Department of Biology, University of Copenhagen, Denmark
Janne Rinne
Natural Resources Institute Finland, Helsinki, Finland
Adrian Rocha
Department of Biological Sciences, University of Notre Dame, USA
Nigel Roulet
McGill University, Canada
Alexandre Roy
Centre d’études nordiques (CEN), Université Laval, Québec, Canada
Universite du Quebec a Trois-Rivieres, Research Centre for Watershed-Aquatic ecosystem interactions (RIVE) , Canada
Anna Rutgersson
Department of Earth Sciences, Uppsala University, Sweden
Aleksandr F. Sabrekov
UNESCO Department "Environmental Dynamics and Global Climate Changes", Yugra State University, Khanty-Mansiysk, Russia
Torsten Sachs
GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
Erik Sahlée
Department of Earth Sciences, Uppsala University, Sweden
Alejandro Salazar
Faculty of Environmental and Forest Sciences, Agricultural University of Iceland, Iceland
Henrique Oliveira Sawakuchi
Department of Thematic Studies-Environmental Change, Linköping University, Linköping, Sweden
Christopher Schulze
Department of Geography, Université de Montréal, QC, Canada
Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
Roger Seco
Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Barcelona, Spain
Armando Sepulveda-Jauregui
Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Stechlin, Germany
Limnological Institute, Department of Biology, University of Konstanz, Konstanz, Germany
Svetlana Serikova
Department of Ecology, Environment and Geoscience, Umeå University, Umeå, Sweden
Abbey Serrone
Civil and Environmental Engineering, University of Washington, USA
Department of Biology and Environmental Sciences, University of Gothenburg, Box 463, SE-40530 Gothenburg, Sweden
Hanna M. Silvennoinen
Norwegian Institute for Nature Research (NINA), Oslo, Norway
Sofie Sjogersten
School of Biosciences, University of Nottingham, Nottingham, United Kingdom
June Skeeter
Department of Geography, University of British Columbia, Vancouver, Canada
Natural Resources Canada, Canada
Jo Snöälv
Department of Geography, University of Exeter, United Kingdom
Sebastian Sobek
Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
Department of Limnology, Uppsala University, Sweden
Oliver Sonnentag
Department of Geography, Université de Montréal, QC, Canada
Emily H. Stanley
Center for Limnology, University of Wisconsin-Madison, Madison, WI 53706, USA
Maria Strack
University of Waterloo, Canada
Lena Strom
Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
Patrick Sullivan
Environment and Natural Resources Institute, University of Alaska Anchorage, Anchorage, AK, USA
Ryan Sullivan
Environmental Science Division, Argonne National Laboratory, Lemont, IL, USA
Anna Sytiuk
Universite de Toulouse, Toulouse INP, CNRS, IRD, CRBE, Toulouse, France
Torbern Tagesson
Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden
Pierre Taillardat
Asian School of the Environment, Nanyang Technological University, 639798 Singapore
Julie Talbot
Department of Geography, Université de Montréal, QC, Canada
Suzanne E. Tank
Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada
Mario Tenuta
Department of Soil Science, University of Manitoba, Winnipeg, Manitoba, Canada
Irina Terenteva
Department of Geography, University of Calgary, Calgary, AB T2N 1N4, Canada
Frederic Thalasso
Department of Biotechnology and Bioengineering Department, Center for Research and Advanced Studies (Cinvestav), Mexico City, Mexico
Antoine Thiboult
Department of Civil and Water Engineering, Universite Laval, QC, Canada
Halldor Thorgeirsson
Icelandic Climate Council, Iceland
Fenix Garcia Tigreros
Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
Margaret Torn
Climate and Ecosystem Sciences Division, Lawrence Berkeley National Laboratory, USA
Amy Townsend-Small
School of Environment and Sustainability, University of Cincinnati, USA
Claire Treat
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Pioneer Center Land-CRAFT, Aarhus University, Denmark
Alain Tremblay
Hydro-Quebec, Quebec, Canada
Carlo Trotta
CMCC Foundation - Euro-Mediterranean Center on Climate Change, Italy
Eeva-Stiina Tuittila
Peatland and Soil Ecology Research Group, School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
Merritt Turetsky
Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO USA
Masahito Ueyama
Graduate School of Agriculture, Osaka Metropolitan University, Sakai 599-8531, Japan
Muhammad Umair
Department of Geography, Université de Montréal, QC, Canada
Aki Vähä
Institute for Atmospheric and Earth System Research, Faculty of Science, University of Helsinki, Finland
Lona van Delden
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Maarten van Hardenbroek
Conservation Ecology Group, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
Andrej Varlagin
A.N. Severtsov Institute of Ecology and Evolution, Russian Academy of Sciences, Moscow, Russia
Ruth K. Varner
Department of Earth Sciences and Institute for the Study of Earth, Oceans and Space, University of New Hampshire, Durham, NH
Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Sweden
Elena Veretennikova
Institute of Monitoring of Climatic and Ecological Systems, Siberian Branch of the Russian Academy of Sciences, Russia
Siberian State Medical University, Russia
Timo Vesala
University of Helsinki, Finland
Tarmo Virtanen
Ecosystems and Environment Research Programme, University of Helsinki, Finland
Carolina Voigt
Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Potsdam, Germany
Department of Geography, Université de Montréal, QC, Canada
Institute of Soil Science, Universität Hamburg, Hamburg, Germany
Jorien E. Vonk
Department of Earth Sciences, Vrije Universiteit, Amsterdam, Netherlands
Robert Wagner
Department of Biology, SDSU, San Diego, CA, USA
Katey Walter Anthony
Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, AK, USA
Qinxue Wang
National Institute for Environmental Studies, Tsukuba, 305-8506, Japan
Masataka Watanabe
Research and Development Initiative, Chuo University, Tokyo 112-8551, Japan
Hailey Webb
Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO USA
Renewable and Sustainable Energy Institute, University of Colorado Boulder, Boulder, CO USA
Jeffrey M. Welker
Department of Biological Sciences, University of Alaska Anchorage, Anchorage, AK, USA
Ecology and Genetics Research Unit, University of Oulu, Oulu, Finland
Andreas Westergaard-Nielsen
Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark
Sebastian Westermann
Center for Biogeochemistry of the Anthropocene, Department of Geosciences, University of Oslo, Oslo, Norway
Jeffrey R. White
Earth and Atmospheric Sciences, Environmental Sciences, Indiana University Bloomington, USA
Christian Wille
GFZ Helmholtz Centre for Geosciences, Potsdam, Germany
Scott N. Williamson
Polar Knowledge Canada, Canadian High Arctic Research Station, Cambridge Bay, Nunavut, Canada
Scott Zolkos
Woodwell Climate Research Center, Falmouth, MA, USA
Donatella Zona
Department of Biology, SDSU, San Diego, CA, USA
Susan M. Natali
Woodwell Climate Research Center, Falmouth, MA, USA
Short summary
This dataset includes monthly measurements of carbon dioxide and methane exchange between land, water, and the atmosphere from over 1,000 sites in Arctic and boreal regions. It combines measurements from a variety of ecosystems, including wetlands, forests, tundra, lakes, and rivers, gathered by over 260 researchers from 1984–2024. This dataset can be used to improve and reduce uncertainty in carbon budgets in order to strengthen our understanding of climate feedbacks in a warming world.
This dataset includes monthly measurements of carbon dioxide and methane exchange between land,...
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Dear Drs. Virkkala, Wargowsky, Vogt, and Kuhn, and co-authors,
I had the pleasure of reading a draft of your manuscript, co-authored with Dr. June Skeeter, entitled ABCFlux v2: Arctic–boreal CO2 and CH4 monthly flux observations and ancillary information across terrestrial and freshwater ecosystems as a part of the required internal review of publications process here at the Department of Natural Resources Canada’s Geological Survey of Canada.
From my perspective I think it is great! Thank you all and your co-authors for your hard work. I think this will be very well cited.
I really only have one suggestion and it is with regard to sub-classification of thaw described on Page 55:
"We further divide the thaw category into 13 categories: active layer detachment, active layer thickening, gradual thaw, ice-wedge degradation, palsa thaw, retrogressive thaw slumps, river bank erosion, subsidence, talik formation, thaw lake, thaw pond, thermokarst, thermokarst mounds with talik."
I think this can be simplified, and here I provide some discussion as to why and provide suggestions on how to do so in my comment. It’s only very a minor part of the work done, but many people are thinking about permafrost thaw, and so this little bit should be more precise. My comments and suggestions are as follows:
-River bank erosion should just be classified as higher-level erosion. It is due to hydro-mechanical processes and not thaw. Mechanical erosive processes also contribute to lateral expansion of thermokarst lakes for example, but this list does not include lake shoreline erosion.
-Active-layer thickening relates to top-down thaw, so does the highly related subsidence, which is a function of active-layer thickening in the presence of ground ice. Active layer-thickening in fine-grained deposits that are frost susceptible (e.g., lacustrine and many morainal deposits) typically results in subsidence and the rate of AL thickening is comparatively slow due to latent heat required to melt ground ice. Active-layer thickening in coarse-grained sediments such as sands and gravels (e.g., glaciofluvial outwash) typically results in comparatively fast increase in AL thickness over time and little to no subsidence as such sediments are not usually associated with near-surface ground ice. Active-layer thickening in areas with exposed bedrock result in no subsidence, and comparatively rapid AL thickening due to very low ground ice contents, but substantial changes to local hydrology cmay occur with implications on drainage and biological functions. I suggest “active layer thickening” and “subsidence” could be meaningfully categorized as “active-layer thickening with subsidence” and “active-layer thickening without subsidence”
-Gradual thaw is not a type of thaw that indicates any sort of genetic origin, and can relate to of several different processes. Talik formation is typically a slow process for example, as is thaw lake expansion. Gradual thaw is not that helpful if the intent is to assign a disturbance. I would delete this sub-category and reassign sites to more relevant thaw categories.
-”Palsa thaw” is presumably a form of top-down thaw leading to active-layer thickening with subsidence, probably also accompanied by lateral permafrost degradation. Collapse of peatlands also occurs with active layer thickening and typically accompanied by lateral degradation. Palsa thaw might be included in a more general peatland sub-class.
-Thermokarst mound formation almost always accompanies ice-wedge degradation, so separating the two may not be necessary.
-"Talik formation" accompanies permafrost degradation associated with development of thaw lakes/ponds, and also top-down thaw associated with active-layer development/permafrost degradation in ice-poor surficial materials, so it accompanies different thaw processes and might not be that instructive to keep as a stand-alone sub-category.
-Thermokarst as a standalone sub-category is not that helpful because it is a blanket term that principally includes (Kokelj and Jorgenson, 2013, Permafrost and Periglac. Process., 24: 108–119, DOI: 10.1002/ppp.1779): “(1) hillslope processes, including retrogressive thaw slumps, active-layer detachment slides (ALDS) and thermal erosion gullies; (2) thaw lake processes [PDM: includes ponds], including lake expansion, drainage and lake basin evolution; and (3) wetland processes, including peatland collapse and the development of bogs and fens.” I suggest reassigning sites from “Thermokarst” to other more meaningful thaw sub-categories.
-Due to the challenges in precisely categorizing one type of thermokarst versus another in the current list, the authors may want to consider simplifying things (e.g., fire is not further classified according to burn severity). I suggest the following: Active layer detachment sliding, retrogressive thaw slumping, ice-wedge degradation with mound formation, ice-wedge degradation without mound formation, active layer thickening with subsidence, active-layer thickening without subsidence, active-layer thickening with talik formation, thaw lake/pond expansion, peatland collapse [this includes peatland degradation where thaw settlement is accompanied by lateral permafrost degradation such as palsa degradation or peat plateau degradation (with resect to this data set the difference is basically a matter of scale) and development of bogs and fens].
-The authors could simplify things even further and simply sub-classify thaw according to predominant processes driving thaw: hillslope processes, thaw lake processes, wetland processes, active layer thickening.
Other than that, I noticed just a few minor things that you probably would have fixed anyway:
Page 62: I'd reference Table 8 for the first time here: "Our annual NEE estimates (Table 8) showed a clear sink-to-source transition from net ... "
Page 62: I'd reference Table 8 again here: "Annual CH4 fluxes (Table 8) demonstrated the ..."
Page 62: Other captions for Figures and Tables that show "tundra" include a sentence like: "The terrestrial tundra class characterizes non-wetland ecosystems in the tundra biome (i.e., dry and moist tundra). "
Best regards,
Peter D. Morse, Ph.D.
Research Scientist / Chercheur scientifique
Geological Survey of Canada | Natural Resources Canada | Government of Canada /
Commission géologique du Canada | Ressources naturelles Canada | Gouvernement du Canada
Adjunct Research Professor, Department of Geography and Environmental Studies, Carleton University
Associate Member, School of Graduate Studies, University of Lethbridge
Secretary, Canadian Permafrost Association (CPA) / l’Association canadienne du pergélisol (l’ACP)