Articles | Volume 10, issue 9
https://doi.org/10.5194/bg-10-5977-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Special issue:
https://doi.org/10.5194/bg-10-5977-2013
© 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 Sep 2013
Research article |
| 11 Sep 2013
Space–time dynamics of carbon and environmental parameters related to carbon dioxide emissions in the Buor-Khaya Bay and adjacent part of the Laptev Sea
I. P. Semiletov
International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, AK, USA
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Science, Vladivostok, Russia
N. E. Shakhova
International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, AK, USA
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Science, Vladivostok, Russia
I. I. Pipko
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Science, Vladivostok, Russia
S. P. Pugach
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Science, Vladivostok, Russia
A. N. Charkin
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Science, Vladivostok, Russia
O. V. Dudarev
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Science, Vladivostok, Russia
D. A. Kosmach
V.I. Il'ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Science, Vladivostok, Russia
S. Nishino
Research Institute for Global Change, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan
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Alexander N. Charkin, Michiel Rutgers van der Loeff, Natalia E. Shakhova, Örjan Gustafsson, Oleg V. Dudarev, Maxim S. Cherepnev, Anatoly N. Salyuk, Andrey V. Koshurnikov, Eduard A. Spivak, Alexey Y. Gunar, Alexey S. Ruban, and Igor P. Semiletov
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Recent Arctic studies suggest that sea-ice decline and permafrost thawing will affect the phytoplankton in the Arctic Ocean. However, in what way the plankton composition will change as the warming proceeds remains elusive. Here we show that the carbon composition of plankton might change as a function of the enhanced terrestrial organic carbon supply and progressive sea-ice thawing.
Thomas M. Cronin, Matt O'Regan, Christof Pearce, Laura Gemery, Michael Toomey, Igor Semiletov, and Martin Jakobsson
Clim. Past, 13, 1097–1110, https://doi.org/10.5194/cp-13-1097-2017, https://doi.org/10.5194/cp-13-1097-2017, 2017
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Global sea level rise during the last deglacial flooded the Siberian continental shelf in the Arctic Ocean. Sediment cores, radiocarbon dating, and microfossils show that the regional sea level in the Arctic rose rapidly from about 12 500 to 10 700 years ago. Regional sea level history on the Siberian shelf differs from the global deglacial sea level rise perhaps due to regional vertical adjustment resulting from the growth and decay of ice sheets.
Jorien E. Vonk, Tommaso Tesi, Lisa Bröder, Henry Holmstrand, Gustaf Hugelius, August Andersson, Oleg Dudarev, Igor Semiletov, and Örjan Gustafsson
The Cryosphere, 11, 1879–1895, https://doi.org/10.5194/tc-11-1879-2017, https://doi.org/10.5194/tc-11-1879-2017, 2017
Martin Jakobsson, Christof Pearce, Thomas M. Cronin, Jan Backman, Leif G. Anderson, Natalia Barrientos, Göran Björk, Helen Coxall, Agatha de Boer, Larry A. Mayer, Carl-Magnus Mörth, Johan Nilsson, Jayne E. Rattray, Christian Stranne, Igor Semiletov, and Matt O'Regan
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The Arctic and Pacific oceans are connected by the presently ~53 m deep Bering Strait. During the last glacial period when the sea level was lower than today, the Bering Strait was exposed. Humans and animals could then migrate between Asia and North America across the formed land bridge. From analyses of sediment cores and geophysical mapping data from Herald Canyon north of the Bering Strait, we show that the land bridge was flooded about 11 000 years ago.
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Vast Arctic methane deposits may alter global climate and require remote sensing (RS) to map. Sonar has great promise, but quantitative inversion based on theory is challenged by multiple bubble acoustical scattering in plumes. We demonstrate use of a real-world in situ bubble plume calibration using a bubble model to correct for differences in the calibration and seep plumes. Spatial seep sonar maps were then used to improve understanding of subsurface geologic controls.
Célia J. Sapart, Natalia Shakhova, Igor Semiletov, Joachim Jansen, Sönke Szidat, Denis Kosmach, Oleg Dudarev, Carina van der Veen, Matthias Egger, Valentine Sergienko, Anatoly Salyuk, Vladimir Tumskoy, Jean-Louis Tison, and Thomas Röckmann
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The Arctic Ocean, especially the Siberian shelves, overlays large areas of subsea permafrost that is degrading. We show that methane with a biogenic origin is emitted from this permafrost. At locations where bubble plumes have been observed, methane can escape oxidation in the surface sediment and rapidly migrate through the very shallow water column of this region to escape to the atmosphere, generating a positive radiative feedback.
Leif G. Anderson, Göran Björk, Ola Holby, Sara Jutterström, Carl Magnus Mörth, Matt O'Regan, Christof Pearce, Igor Semiletov, Christian Stranne, Tim Stöven, Toste Tanhua, Adam Ulfsbo, and Martin Jakobsson
Ocean Sci., 13, 349–363, https://doi.org/10.5194/os-13-349-2017, https://doi.org/10.5194/os-13-349-2017, 2017
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We use data collected in 2014 to show that the outflow of nutrient-rich water occurs much further to the west than has been reported in the past. We suggest that this is due to much less summer sea-ice coverage in the northwestern East Siberian Sea than in the past decades. Further, our data support a more complicated flow pattern in the region where the Mendeleev Ridge reaches the shelf compared to the general cyclonic circulation within the individual basins as suggested historically.
Christof Pearce, Aron Varhelyi, Stefan Wastegård, Francesco Muschitiello, Natalia Barrientos, Matt O'Regan, Thomas M. Cronin, Laura Gemery, Igor Semiletov, Jan Backman, and Martin Jakobsson
Clim. Past, 13, 303–316, https://doi.org/10.5194/cp-13-303-2017, https://doi.org/10.5194/cp-13-303-2017, 2017
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The eruption of the Alaskan Aniakchak volcano of 3.6 thousand years ago was one of the largest Holocene eruptions worldwide. The resulting ash is found in several Alaskan sites and as far as Newfoundland and Greenland. In this study, we found ash from the Aniakchak eruption in a marine sediment core from the western Chukchi Sea in the Arctic Ocean. Combined with radiocarbon dates on mollusks, the volcanic age marker is used to calculate the marine radiocarbon reservoir age at that time.
Leif G. Anderson, Jörgen Ek, Ylva Ericson, Christoph Humborg, Igor Semiletov, Marcus Sundbom, and Adam Ulfsbo
Biogeosciences, 14, 1811–1823, https://doi.org/10.5194/bg-14-1811-2017, https://doi.org/10.5194/bg-14-1811-2017, 2017
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Waters with very high pCO2, nutrients and low oxygen concentrations were observed along the continental margin of the East Siberian Sea and well out into the deep Makarov and Canada basins during the SWERUS-C3 expedition in 2014. This water had a low saturation state with respect to calcium carbonate, down to less than 0.8 for calcite and 0.5 for aragonite, and is traced in historic data to the Canada Basin and in the waters flowing out of the Arctic Ocean in the western Fram Strait.
Erik Gustafsson, Christoph Humborg, Göran Björk, Christian Stranne, Leif G. Anderson, Marc C. Geibel, Carl-Magnus Mörth, Marcus Sundbom, Igor P. Semiletov, Brett F. Thornton, and Bo G. Gustafsson
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-115, https://doi.org/10.5194/bg-2017-115, 2017
Preprint withdrawn
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In this study we quantify key carbon cycling processes on the East Siberian Arctic Shelf. A specific aim is to determine the pathways of terrestrial organic carbon (OC) supplied by rivers and coastline erosion – and particularly to what extent degradation of terrestrial OC contributes to air-sea CO2 exchange. We estimate that the shelf is a weak CO2 sink, although this sink is considerably reduced mainly by degradation of eroded OC and to a lesser extent by degradation of riverine OC.
Joan A. Salvadó, Tommaso Tesi, Marcus Sundbom, Emma Karlsson, Martin Kruså, Igor P. Semiletov, Elena Panova, and Örjan Gustafsson
Biogeosciences, 13, 6121–6138, https://doi.org/10.5194/bg-13-6121-2016, https://doi.org/10.5194/bg-13-6121-2016, 2016
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Fluvial discharge and coastal erosion of the permafrost-dominated East Siberian Arctic delivers large quantities of terrigenous organic carbon (Terr-OC) to marine waters. We assessed its fate and composition in different marine pools with a suite of biomarkers. The dissolved organic carbon is transporting off-shelf “young” and fresh vascular plant material, while sedimentary and near-bottom particulate organic carbon preferentially carries old organic carbon released from thawing permafrost.
Robert B. Sparkes, Ayça Doğrul Selver, Örjan Gustafsson, Igor P. Semiletov, Negar Haghipour, Lukas Wacker, Timothy I. Eglinton, Helen M. Talbot, and Bart E. van Dongen
The Cryosphere, 10, 2485–2500, https://doi.org/10.5194/tc-10-2485-2016, https://doi.org/10.5194/tc-10-2485-2016, 2016
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The permafrost in eastern Siberia contains large amounts of carbon frozen in soils and sediments. Continuing global warming is thawing the permafrost and releasing carbon to the Arctic Ocean. We used pyrolysis-GCMS, a chemical fingerprinting technique, to study the types of carbon being deposited on the continental shelf. We found large amounts of permafrost-sourced carbon being deposited up to 200 km offshore.
Lisa Bröder, Tommaso Tesi, Joan A. Salvadó, Igor P. Semiletov, Oleg V. Dudarev, and Örjan Gustafsson
Biogeosciences, 13, 5003–5019, https://doi.org/10.5194/bg-13-5003-2016, https://doi.org/10.5194/bg-13-5003-2016, 2016
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Thawing permafrost may release large amounts of terrestrial organic carbon (TerrOC) to the Arctic Ocean. We assessed its fate in the marine environment with a suite of biomarkers. Across the Laptev Sea their concentrations in surface sediments decreased significantly and showed a trend to qualitatively more degraded TerrOC with increasing water depth. We infer that the degree of degradation of TerrOC is a function of the time spent under oxic conditions during protracted cross-shelf transport.
Juliane Bischoff, Robert B. Sparkes, Ayça Doğrul Selver, Robert G. M. Spencer, Örjan Gustafsson, Igor P. Semiletov, Oleg V. Dudarev, Dirk Wagner, Elizaveta Rivkina, Bart E. van Dongen, and Helen M. Talbot
Biogeosciences, 13, 4899–4914, https://doi.org/10.5194/bg-13-4899-2016, https://doi.org/10.5194/bg-13-4899-2016, 2016
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The Arctic contains a large pool of carbon that is vulnerable to warming and can be released by rivers and coastal erosion. We study microbial lipids (BHPs) in permafrost and shelf sediments to trace the source, transport and fate of this carbon. BHPs in permafrost deposits are released to the shelf by rivers and coastal erosion, in contrast to other microbial lipids (GDGTs) that are transported by rivers. Several further analyses are needed to understand the complex East Siberian Shelf system.
X. Feng, Ö. Gustafsson, R. M. Holmes, J. E. Vonk, B. E. van Dongen, I. P. Semiletov, O. V. Dudarev, M. B. Yunker, R. W. Macdonald, D. B. Montluçon, and T. I. Eglinton
Biogeosciences, 12, 4841–4860, https://doi.org/10.5194/bg-12-4841-2015, https://doi.org/10.5194/bg-12-4841-2015, 2015
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Currently very few studies have examined the distribution and fate of hydrolyzable organic carbon (OC) in Arctic sediments, whose fate remains unclear in the context of climate change. Our study focuses on the source, distribution and fate of hydrolyzable OC as compared with plant wax lipids and lignin phenols in the sedimentary particles of nine Arctic and sub-Arctic rivers. This multi-molecular approach allows for a comprehensive investigation of terrestrial OC transfer via Arctic rivers.
R. B. Sparkes, A. Doğrul Selver, J. Bischoff, H. M. Talbot, Ö. Gustafsson, I. P. Semiletov, O. V. Dudarev, and B. E. van Dongen
Biogeosciences, 12, 3753–3768, https://doi.org/10.5194/bg-12-3753-2015, https://doi.org/10.5194/bg-12-3753-2015, 2015
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Siberian permafrost contains large amounts of organic carbon that may be released by climate warming. We collected and analysed samples from the East Siberian Sea, using GDGT biomarkers to trace the sourcing and deposition of organic carbon across the shelf. We show that branched GDGTs may be used to trace river erosion. Results from modelling show that organic carbon on the shelf is a complex process involving river-derived and coastal-derived material as well as marine carbon production.
Peter Edward Land, Helen S. Findlay, Jamie D. Shutler, Jean-Francois Piolle, Richard Sims, Hannah Green, Vassilis Kitidis, Alexander Polukhin, and Irina I. Pipko
Earth Syst. Sci. Data, 15, 921–947, https://doi.org/10.5194/essd-15-921-2023, https://doi.org/10.5194/essd-15-921-2023, 2023
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Measurements of the ocean’s carbonate system (e.g. CO2 and pH) have increased greatly in recent years, resulting in a need to combine these data with satellite measurements and model results, so they can be used to test predictions of how the ocean reacts to changes such as absorption of the CO2 emitted by humans. We show a method of combining data into regions of interest (100 km circles over a 10 d period) and apply it globally to produce a harmonised and easy-to-use data archive.
Jaclyn Clement Kinney, Karen M. Assmann, Wieslaw Maslowski, Göran Björk, Martin Jakobsson, Sara Jutterström, Younjoo J. Lee, Robert Osinski, Igor Semiletov, Adam Ulfsbo, Irene Wåhlström, and Leif G. Anderson
Ocean Sci., 18, 29–49, https://doi.org/10.5194/os-18-29-2022, https://doi.org/10.5194/os-18-29-2022, 2022
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We use data crossing Herald Canyon in the Chukchi Sea collected in 2008 and 2014 together with numerical modelling to investigate the circulation in the western Chukchi Sea. A large fraction of water from the Chukchi Sea enters the East Siberian Sea south of Wrangel Island and circulates in an anticyclonic direction around the island. To assess the differences between years, we use numerical modelling results, which show that high-frequency variability dominates the flow in Herald Canyon.
Jannik Martens, Evgeny Romankevich, Igor Semiletov, Birgit Wild, Bart van Dongen, Jorien Vonk, Tommaso Tesi, Natalia Shakhova, Oleg V. Dudarev, Denis Kosmach, Alexander Vetrov, Leopold Lobkovsky, Nikolay Belyaev, Robie W. Macdonald, Anna J. Pieńkowski, Timothy I. Eglinton, Negar Haghipour, Salve Dahle, Michael L. Carroll, Emmelie K. L. Åström, Jacqueline M. Grebmeier, Lee W. Cooper, Göran Possnert, and Örjan Gustafsson
Earth Syst. Sci. Data, 13, 2561–2572, https://doi.org/10.5194/essd-13-2561-2021, https://doi.org/10.5194/essd-13-2561-2021, 2021
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The paper describes the establishment, structure and current status of the first Circum-Arctic Sediment CArbon DatabasE (CASCADE), which is a scientific effort to harmonize and curate all published and unpublished data of carbon, nitrogen, carbon isotopes, and terrigenous biomarkers in sediments of the Arctic Ocean in one database. CASCADE will enable a variety of studies of the Arctic carbon cycle and thus contribute to a better understanding of how climate change affects the Arctic.
Alexander Osadchiev, Igor Medvedev, Sergey Shchuka, Mikhail Kulikov, Eduard Spivak, Maria Pisareva, and Igor Semiletov
Ocean Sci., 16, 781–798, https://doi.org/10.5194/os-16-781-2020, https://doi.org/10.5194/os-16-781-2020, 2020
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The Yenisei and Khatanga rivers are among the largest estuarine rivers that inflow to the Arctic Ocean. Discharge of the Yenisei River is 1 order of magnitude larger than that of the Khatanga River. However, spatial scales of buoyant plumes formed by freshwater runoff from the Yenisei and Khatanga gulfs are similar. This feature is caused by intense tidal mixing in the Khatanga Gulf, which causes formation of the diluted and therefore anomalously deep and large Khatanga plume.
Sarah Conrad, Johan Ingri, Johan Gelting, Fredrik Nordblad, Emma Engström, Ilia Rodushkin, Per S. Andersson, Don Porcelli, Örjan Gustafsson, Igor Semiletov, and Björn Öhlander
Biogeosciences, 16, 1305–1319, https://doi.org/10.5194/bg-16-1305-2019, https://doi.org/10.5194/bg-16-1305-2019, 2019
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Iron analysis of the particulate, colloidal, and truly dissolved fractions along the Lena River freshwater plume showed that the particulate iron dominates close to the coast. Over 99 % particulate and about 90 % colloidal iron were lost, while the truly dissolved phase was almost constant. Iron isotopes suggest that the shelf acts as a sink for particles and colloids with negative iron isotope values, while colloids with positive iron isotope values travel further out into the Arctic Ocean.
Birgit Wild, Natalia Shakhova, Oleg Dudarev, Alexey Ruban, Denis Kosmach, Vladimir Tumskoy, Tommaso Tesi, Hanna Joß, Helena Alexanderson, Martin Jakobsson, Alexey Mazurov, Igor Semiletov, and Örjan Gustafsson
The Cryosphere Discuss., https://doi.org/10.5194/tc-2018-229, https://doi.org/10.5194/tc-2018-229, 2018
Revised manuscript not accepted
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The thaw and degradation of subsea permafrost on the Arctic Ocean shelves is one of the key uncertainties concerning natural greenhouse gas emissions since difficult access limits the availability of observational data. In this study, we describe sediment properties and age constraints of a unique set of three subsea permafrost cores from the East Siberian Arctic Shelf, as well as content, origin and degradation state of organic matter at the current thaw front.
Robert B. Sparkes, Melissa Maher, Jerome Blewett, Ayça Doğrul Selver, Örjan Gustafsson, Igor P. Semiletov, and Bart E. van Dongen
The Cryosphere, 12, 3293–3309, https://doi.org/10.5194/tc-12-3293-2018, https://doi.org/10.5194/tc-12-3293-2018, 2018
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Ongoing climate change in the Siberian Arctic region has the potential to release large amounts of carbon, currently stored in permafrost, to the Arctic Shelf. Degradation can release this to the atmosphere as greenhouse gas. We used Raman spectroscopy to analyse a fraction of this carbon, carbonaceous material, a group that includes coal, lignite and graphite. We were able to trace this carbon from the river mouths and coastal erosion sites across the Arctic shelf for hundreds of kilometres.
Svetlana P. Pugach, Irina I. Pipko, Natalia E. Shakhova, Evgeny A. Shirshin, Irina V. Perminova, Örjan Gustafsson, Valery G. Bondur, Alexey S. Ruban, and Igor P. Semiletov
Ocean Sci., 14, 87–103, https://doi.org/10.5194/os-14-87-2018, https://doi.org/10.5194/os-14-87-2018, 2018
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This paper explores the possibility of using CDOM and its spectral parameters to identify the different biogeochemical regimes on the ESAS. The strong correlation between DOC and CDOM values in the surface shelf waters influenced by terrigenous discharge indicates that it is feasible to estimate DOC content from CDOM fluorescence assessed in situ. The direct estimation of DOM optical parameters in the surface ESAS waters provided by this study will be useful for validating remote sensing data.
Volker Brüchert, Lisa Bröder, Joanna E. Sawicka, Tommaso Tesi, Samantha P. Joye, Xiaole Sun, Igor P. Semiletov, and Vladimir A. Samarkin
Biogeosciences, 15, 471–490, https://doi.org/10.5194/bg-15-471-2018, https://doi.org/10.5194/bg-15-471-2018, 2018
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We determined the aerobic and anaerobic degradation rates of land- and marine-derived organic material in East Siberian shelf sediment. Marine plankton-derived organic carbon was the main source for the oxic dissolved carbon dioxide production, whereas terrestrial organic material significantly contributed to the production of carbon dioxide under anoxic conditions. Our direct degradation rate measurements provide new constraints for the present-day Arctic marine carbon budget.
Naohiro Kosugi, Daisuke Sasano, Masao Ishii, Shigeto Nishino, Hiroshi Uchida, and Hisayuki Yoshikawa-Inoue
Biogeosciences, 14, 5727–5739, https://doi.org/10.5194/bg-14-5727-2017, https://doi.org/10.5194/bg-14-5727-2017, 2017
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Recent variation in air–sea CO2 flux in the Arctic Ocean is focused. In order to understand the relation between sea ice retreat and CO2 chemistry, we conducted hydrographic observations in the Arctic Ocean in 2013. There were relatively high pCO2 surface layer and low pCO2 subsurface layer in the Canada Basin. The former was due to near-equilibration with the atmosphere and the latter primary production. Both were unlikely mixed by disturbance as large sea-ice melt formed strong stratification.
Irina I. Pipko, Svetlana P. Pugach, Igor P. Semiletov, Leif G. Anderson, Natalia E. Shakhova, Örjan Gustafsson, Irina A. Repina, Eduard A. Spivak, Alexander N. Charkin, Anatoly N. Salyuk, Kseniia P. Shcherbakova, Elena V. Panova, and Oleg V. Dudarev
Ocean Sci., 13, 997–1016, https://doi.org/10.5194/os-13-997-2017, https://doi.org/10.5194/os-13-997-2017, 2017
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The study of the outer shelf and the continental slope waters of the Eurasian Arctic seas has revealed a general trend in the surface pCO2 distribution, which manifested as an increase in pCO2 values eastward. It has been shown that the influence of terrestrial discharge on the carbonate system of East Siberian Arctic sea surface waters is not limited to the shallow shelf and that contemporary climate change impacts the carbon cycle of the Eurasian Arctic Ocean and influences air–sea CO2 flux.
Alexander N. Charkin, Michiel Rutgers van der Loeff, Natalia E. Shakhova, Örjan Gustafsson, Oleg V. Dudarev, Maxim S. Cherepnev, Anatoly N. Salyuk, Andrey V. Koshurnikov, Eduard A. Spivak, Alexey Y. Gunar, Alexey S. Ruban, and Igor P. Semiletov
The Cryosphere, 11, 2305–2327, https://doi.org/10.5194/tc-11-2305-2017, https://doi.org/10.5194/tc-11-2305-2017, 2017
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This study tests the hypothesis that SGD exists in the Siberian Arctic shelf seas, but its dynamics may be largely controlled by complicated geocryological conditions such as permafrost. The permafrost cements rocks, forms a confining bed, and as a result makes it difficult for the groundwater escape to the shelf surface. However, the discovery of subterranean outcrops of groundwater springs in the Buor-Khaya Gulf are clear evidence that a groundwater flow system exists in the environment.
Matt O'Regan, Jan Backman, Natalia Barrientos, Thomas M. Cronin, Laura Gemery, Nina Kirchner, Larry A. Mayer, Johan Nilsson, Riko Noormets, Christof Pearce, Igor Semiletov, Christian Stranne, and Martin Jakobsson
Clim. Past, 13, 1269–1284, https://doi.org/10.5194/cp-13-1269-2017, https://doi.org/10.5194/cp-13-1269-2017, 2017
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Past glacial activity on the East Siberian continental margin is poorly known, partly due to the lack of geomorphological evidence. Here we present geophysical mapping and sediment coring data from the East Siberian shelf and slope revealing the presence of a glacially excavated cross-shelf trough reaching to the continental shelf edge north of the De Long Islands. The data provide direct evidence for extensive glacial activity on the Siberian shelf that predates the Last Glacial Maximum.
Kirsi Keskitalo, Tommaso Tesi, Lisa Bröder, August Andersson, Christof Pearce, Martin Sköld, Igor P. Semiletov, Oleg V. Dudarev, and Örjan Gustafsson
Clim. Past, 13, 1213–1226, https://doi.org/10.5194/cp-13-1213-2017, https://doi.org/10.5194/cp-13-1213-2017, 2017
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In this study we investigate land-to-ocean transfer and the fate of permafrost carbon in the East Siberian Sea from the early Holocene until the present day. Our results suggest that there was a high input of terrestrial organic carbon to the East Siberian Sea during the last glacial–interglacial period caused by permafrost destabilisation. This material was mainly characterised as relict Pleistocene permafrost deposited via coastal erosion as a result of the sea level rise.
Tommaso Tesi, Marc C. Geibel, Christof Pearce, Elena Panova, Jorien E. Vonk, Emma Karlsson, Joan A. Salvado, Martin Kruså, Lisa Bröder, Christoph Humborg, Igor Semiletov, and Örjan Gustafsson
Ocean Sci., 13, 735–748, https://doi.org/10.5194/os-13-735-2017, https://doi.org/10.5194/os-13-735-2017, 2017
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Recent Arctic studies suggest that sea-ice decline and permafrost thawing will affect the phytoplankton in the Arctic Ocean. However, in what way the plankton composition will change as the warming proceeds remains elusive. Here we show that the carbon composition of plankton might change as a function of the enhanced terrestrial organic carbon supply and progressive sea-ice thawing.
Thomas M. Cronin, Matt O'Regan, Christof Pearce, Laura Gemery, Michael Toomey, Igor Semiletov, and Martin Jakobsson
Clim. Past, 13, 1097–1110, https://doi.org/10.5194/cp-13-1097-2017, https://doi.org/10.5194/cp-13-1097-2017, 2017
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Global sea level rise during the last deglacial flooded the Siberian continental shelf in the Arctic Ocean. Sediment cores, radiocarbon dating, and microfossils show that the regional sea level in the Arctic rose rapidly from about 12 500 to 10 700 years ago. Regional sea level history on the Siberian shelf differs from the global deglacial sea level rise perhaps due to regional vertical adjustment resulting from the growth and decay of ice sheets.
Jorien E. Vonk, Tommaso Tesi, Lisa Bröder, Henry Holmstrand, Gustaf Hugelius, August Andersson, Oleg Dudarev, Igor Semiletov, and Örjan Gustafsson
The Cryosphere, 11, 1879–1895, https://doi.org/10.5194/tc-11-1879-2017, https://doi.org/10.5194/tc-11-1879-2017, 2017
Martin Jakobsson, Christof Pearce, Thomas M. Cronin, Jan Backman, Leif G. Anderson, Natalia Barrientos, Göran Björk, Helen Coxall, Agatha de Boer, Larry A. Mayer, Carl-Magnus Mörth, Johan Nilsson, Jayne E. Rattray, Christian Stranne, Igor Semiletov, and Matt O'Regan
Clim. Past, 13, 991–1005, https://doi.org/10.5194/cp-13-991-2017, https://doi.org/10.5194/cp-13-991-2017, 2017
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The Arctic and Pacific oceans are connected by the presently ~53 m deep Bering Strait. During the last glacial period when the sea level was lower than today, the Bering Strait was exposed. Humans and animals could then migrate between Asia and North America across the formed land bridge. From analyses of sediment cores and geophysical mapping data from Herald Canyon north of the Bering Strait, we show that the land bridge was flooded about 11 000 years ago.
Ira Leifer, Denis Chernykh, Natalia Shakhova, and Igor Semiletov
The Cryosphere, 11, 1333–1350, https://doi.org/10.5194/tc-11-1333-2017, https://doi.org/10.5194/tc-11-1333-2017, 2017
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Vast Arctic methane deposits may alter global climate and require remote sensing (RS) to map. Sonar has great promise, but quantitative inversion based on theory is challenged by multiple bubble acoustical scattering in plumes. We demonstrate use of a real-world in situ bubble plume calibration using a bubble model to correct for differences in the calibration and seep plumes. Spatial seep sonar maps were then used to improve understanding of subsurface geologic controls.
Célia J. Sapart, Natalia Shakhova, Igor Semiletov, Joachim Jansen, Sönke Szidat, Denis Kosmach, Oleg Dudarev, Carina van der Veen, Matthias Egger, Valentine Sergienko, Anatoly Salyuk, Vladimir Tumskoy, Jean-Louis Tison, and Thomas Röckmann
Biogeosciences, 14, 2283–2292, https://doi.org/10.5194/bg-14-2283-2017, https://doi.org/10.5194/bg-14-2283-2017, 2017
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The Arctic Ocean, especially the Siberian shelves, overlays large areas of subsea permafrost that is degrading. We show that methane with a biogenic origin is emitted from this permafrost. At locations where bubble plumes have been observed, methane can escape oxidation in the surface sediment and rapidly migrate through the very shallow water column of this region to escape to the atmosphere, generating a positive radiative feedback.
Leif G. Anderson, Göran Björk, Ola Holby, Sara Jutterström, Carl Magnus Mörth, Matt O'Regan, Christof Pearce, Igor Semiletov, Christian Stranne, Tim Stöven, Toste Tanhua, Adam Ulfsbo, and Martin Jakobsson
Ocean Sci., 13, 349–363, https://doi.org/10.5194/os-13-349-2017, https://doi.org/10.5194/os-13-349-2017, 2017
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We use data collected in 2014 to show that the outflow of nutrient-rich water occurs much further to the west than has been reported in the past. We suggest that this is due to much less summer sea-ice coverage in the northwestern East Siberian Sea than in the past decades. Further, our data support a more complicated flow pattern in the region where the Mendeleev Ridge reaches the shelf compared to the general cyclonic circulation within the individual basins as suggested historically.
Christof Pearce, Aron Varhelyi, Stefan Wastegård, Francesco Muschitiello, Natalia Barrientos, Matt O'Regan, Thomas M. Cronin, Laura Gemery, Igor Semiletov, Jan Backman, and Martin Jakobsson
Clim. Past, 13, 303–316, https://doi.org/10.5194/cp-13-303-2017, https://doi.org/10.5194/cp-13-303-2017, 2017
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The eruption of the Alaskan Aniakchak volcano of 3.6 thousand years ago was one of the largest Holocene eruptions worldwide. The resulting ash is found in several Alaskan sites and as far as Newfoundland and Greenland. In this study, we found ash from the Aniakchak eruption in a marine sediment core from the western Chukchi Sea in the Arctic Ocean. Combined with radiocarbon dates on mollusks, the volcanic age marker is used to calculate the marine radiocarbon reservoir age at that time.
Leif G. Anderson, Jörgen Ek, Ylva Ericson, Christoph Humborg, Igor Semiletov, Marcus Sundbom, and Adam Ulfsbo
Biogeosciences, 14, 1811–1823, https://doi.org/10.5194/bg-14-1811-2017, https://doi.org/10.5194/bg-14-1811-2017, 2017
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Waters with very high pCO2, nutrients and low oxygen concentrations were observed along the continental margin of the East Siberian Sea and well out into the deep Makarov and Canada basins during the SWERUS-C3 expedition in 2014. This water had a low saturation state with respect to calcium carbonate, down to less than 0.8 for calcite and 0.5 for aragonite, and is traced in historic data to the Canada Basin and in the waters flowing out of the Arctic Ocean in the western Fram Strait.
Erik Gustafsson, Christoph Humborg, Göran Björk, Christian Stranne, Leif G. Anderson, Marc C. Geibel, Carl-Magnus Mörth, Marcus Sundbom, Igor P. Semiletov, Brett F. Thornton, and Bo G. Gustafsson
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-115, https://doi.org/10.5194/bg-2017-115, 2017
Preprint withdrawn
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In this study we quantify key carbon cycling processes on the East Siberian Arctic Shelf. A specific aim is to determine the pathways of terrestrial organic carbon (OC) supplied by rivers and coastline erosion – and particularly to what extent degradation of terrestrial OC contributes to air-sea CO2 exchange. We estimate that the shelf is a weak CO2 sink, although this sink is considerably reduced mainly by degradation of eroded OC and to a lesser extent by degradation of riverine OC.
Michiyo Yamamoto-Kawai, Takahisa Mifune, Takashi Kikuchi, and Shigeto Nishino
Biogeosciences, 13, 6155–6169, https://doi.org/10.5194/bg-13-6155-2016, https://doi.org/10.5194/bg-13-6155-2016, 2016
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Seasonal variation of Ω in bottom water in Hope Valley, a biological hotspot in the southern Chukchi Sea, was reconstructed from 2-year-round mooring data of temperature, salinity and oxygen, with empirical equations derived from ship-based observations.
Joan A. Salvadó, Tommaso Tesi, Marcus Sundbom, Emma Karlsson, Martin Kruså, Igor P. Semiletov, Elena Panova, and Örjan Gustafsson
Biogeosciences, 13, 6121–6138, https://doi.org/10.5194/bg-13-6121-2016, https://doi.org/10.5194/bg-13-6121-2016, 2016
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Fluvial discharge and coastal erosion of the permafrost-dominated East Siberian Arctic delivers large quantities of terrigenous organic carbon (Terr-OC) to marine waters. We assessed its fate and composition in different marine pools with a suite of biomarkers. The dissolved organic carbon is transporting off-shelf “young” and fresh vascular plant material, while sedimentary and near-bottom particulate organic carbon preferentially carries old organic carbon released from thawing permafrost.
Robert B. Sparkes, Ayça Doğrul Selver, Örjan Gustafsson, Igor P. Semiletov, Negar Haghipour, Lukas Wacker, Timothy I. Eglinton, Helen M. Talbot, and Bart E. van Dongen
The Cryosphere, 10, 2485–2500, https://doi.org/10.5194/tc-10-2485-2016, https://doi.org/10.5194/tc-10-2485-2016, 2016
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The permafrost in eastern Siberia contains large amounts of carbon frozen in soils and sediments. Continuing global warming is thawing the permafrost and releasing carbon to the Arctic Ocean. We used pyrolysis-GCMS, a chemical fingerprinting technique, to study the types of carbon being deposited on the continental shelf. We found large amounts of permafrost-sourced carbon being deposited up to 200 km offshore.
Lisa Bröder, Tommaso Tesi, Joan A. Salvadó, Igor P. Semiletov, Oleg V. Dudarev, and Örjan Gustafsson
Biogeosciences, 13, 5003–5019, https://doi.org/10.5194/bg-13-5003-2016, https://doi.org/10.5194/bg-13-5003-2016, 2016
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Thawing permafrost may release large amounts of terrestrial organic carbon (TerrOC) to the Arctic Ocean. We assessed its fate in the marine environment with a suite of biomarkers. Across the Laptev Sea their concentrations in surface sediments decreased significantly and showed a trend to qualitatively more degraded TerrOC with increasing water depth. We infer that the degree of degradation of TerrOC is a function of the time spent under oxic conditions during protracted cross-shelf transport.
Juliane Bischoff, Robert B. Sparkes, Ayça Doğrul Selver, Robert G. M. Spencer, Örjan Gustafsson, Igor P. Semiletov, Oleg V. Dudarev, Dirk Wagner, Elizaveta Rivkina, Bart E. van Dongen, and Helen M. Talbot
Biogeosciences, 13, 4899–4914, https://doi.org/10.5194/bg-13-4899-2016, https://doi.org/10.5194/bg-13-4899-2016, 2016
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The Arctic contains a large pool of carbon that is vulnerable to warming and can be released by rivers and coastal erosion. We study microbial lipids (BHPs) in permafrost and shelf sediments to trace the source, transport and fate of this carbon. BHPs in permafrost deposits are released to the shelf by rivers and coastal erosion, in contrast to other microbial lipids (GDGTs) that are transported by rivers. Several further analyses are needed to understand the complex East Siberian Shelf system.
Shigeto Nishino, Takashi Kikuchi, Amane Fujiwara, Toru Hirawake, and Michio Aoyama
Biogeosciences, 13, 2563–2578, https://doi.org/10.5194/bg-13-2563-2016, https://doi.org/10.5194/bg-13-2563-2016, 2016
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We analysed mooring and ship-based data obtained from a biological hotspot in the southern Chukchi Sea. Mooring data were collected for the first time in this site and were captured during spring and autumn blooms with high chlorophyll a concentrations. The data suggest that a dome-like structure of the bottom water and nutrient regeneration at the bottom play important roles in maintaining the autumn bloom of the biological hotspot.
Naoya Yokoi, Kohei Matsuno, Mutsuo Ichinomiya, Atsushi Yamaguchi, Shigeto Nishino, Jonaotaro Onodera, Jun Inoue, and Takashi Kikuchi
Biogeosciences, 13, 913–923, https://doi.org/10.5194/bg-13-913-2016, https://doi.org/10.5194/bg-13-913-2016, 2016
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We studied short-term changes in the microplankton community in the Chukchi Sea with regards to responses to the strong wind event (SWE) during autumn (September 2013). It is assumed that atmospheric turbulences, such as SWE, may supply sufficient nutrients to the surface layer that subsequently enhance the small bloom under the weak stratification. After the bloom, the dominant diatom community then shifts from centric-dominated to one where centric/pennate are more equal in abundance.
A. Fujiwara, T. Hirawake, K. Suzuki, L. Eisner, I. Imai, S. Nishino, T. Kikuchi, and S.-I. Saitoh
Biogeosciences, 13, 115–131, https://doi.org/10.5194/bg-13-115-2016, https://doi.org/10.5194/bg-13-115-2016, 2016
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This study provides the general relationship between the timing of sea ice retreat and phytoplankton size structure during the marginal ice zone bloom period in the Chukchi and Bering shelves using a satellite remote sensing approach. We also found that not only the length of the ice-free season but also the annual phytoplankton size composition positively correlated with annual net primary production.
A. Ooki, S. Kawasaki, K. Kuma, S. Nishino, and T. Kikuchi
Biogeosciences, 13, 133–145, https://doi.org/10.5194/bg-13-133-2016, https://doi.org/10.5194/bg-13-133-2016, 2016
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We conducted a shipboard observation over the Chukchi Sea and the Canada Basin
in the western Arctic Ocean to obtain vertical distributions of four volatile organic iodine compounds (VOIs) in seawater. High concentrations of four VOIs were found in the bottom layer water over the Chukchi Sea shelf, in which layer the concentration maximum of ammonium occurred simultaneously. We considered that the VOI production is associated with degradation of organic matter in the bottom sediment.
X. Feng, Ö. Gustafsson, R. M. Holmes, J. E. Vonk, B. E. van Dongen, I. P. Semiletov, O. V. Dudarev, M. B. Yunker, R. W. Macdonald, D. B. Montluçon, and T. I. Eglinton
Biogeosciences, 12, 4841–4860, https://doi.org/10.5194/bg-12-4841-2015, https://doi.org/10.5194/bg-12-4841-2015, 2015
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Currently very few studies have examined the distribution and fate of hydrolyzable organic carbon (OC) in Arctic sediments, whose fate remains unclear in the context of climate change. Our study focuses on the source, distribution and fate of hydrolyzable OC as compared with plant wax lipids and lignin phenols in the sedimentary particles of nine Arctic and sub-Arctic rivers. This multi-molecular approach allows for a comprehensive investigation of terrestrial OC transfer via Arctic rivers.
K. Matsuno, A. Yamaguchi, S. Nishino, J. Inoue, and T. Kikuchi
Biogeosciences, 12, 4005–4015, https://doi.org/10.5194/bg-12-4005-2015, https://doi.org/10.5194/bg-12-4005-2015, 2015
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We performed high-frequency samplings of zooplankton community and gut pigment of copepods in the Chukchi Sea. Zooplankton showed no changes with a strong wind event and dominant copepods prepared for diapause. Yet, feeding activity of the copepods increased as a result of temporal phytoplankton bloom, enhanced by the wind event. Because of the long generation length of copepods, a smaller effect was detected for their abundance, population, lipid accumulation and gonad maturation.
R. B. Sparkes, A. Doğrul Selver, J. Bischoff, H. M. Talbot, Ö. Gustafsson, I. P. Semiletov, O. V. Dudarev, and B. E. van Dongen
Biogeosciences, 12, 3753–3768, https://doi.org/10.5194/bg-12-3753-2015, https://doi.org/10.5194/bg-12-3753-2015, 2015
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Siberian permafrost contains large amounts of organic carbon that may be released by climate warming. We collected and analysed samples from the East Siberian Sea, using GDGT biomarkers to trace the sourcing and deposition of organic carbon across the shelf. We show that branched GDGTs may be used to trace river erosion. Results from modelling show that organic carbon on the shelf is a complex process involving river-derived and coastal-derived material as well as marine carbon production.
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Thea H. Heimdal, Galen A. McKinley, Adrienne J. Sutton, Amanda R. Fay, and Lucas Gloege
Biogeosciences, 21, 2159–2176, https://doi.org/10.5194/bg-21-2159-2024, https://doi.org/10.5194/bg-21-2159-2024, 2024
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Measurements of ocean carbon are limited in time and space. Machine learning algorithms are therefore used to reconstruct ocean carbon where observations do not exist. Improving these reconstructions is important in order to accurately estimate how much carbon the ocean absorbs from the atmosphere. In this study, we find that a small addition of observations from the Southern Ocean, obtained by autonomous sampling platforms, could significantly improve the reconstructions.
Guilherme L. Torres Mendonça, Julia Pongratz, and Christian H. Reick
Biogeosciences, 21, 1923–1960, https://doi.org/10.5194/bg-21-1923-2024, https://doi.org/10.5194/bg-21-1923-2024, 2024
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We study the timescale dependence of airborne fraction and underlying feedbacks by a theory of the climate–carbon system. Using simulations we show the predictive power of this theory and find that (1) this fraction generally decreases for increasing timescales and (2) at all timescales the total feedback is negative and the model spread in a single feedback causes the spread in the airborne fraction. Our study indicates that those are properties of the system, independently of the scenario.
François Clayer, Jan Erik Thrane, Kuria Ndungu, Andrew King, Peter Dörsch, and Thomas Rohrlack
Biogeosciences, 21, 1903–1921, https://doi.org/10.5194/bg-21-1903-2024, https://doi.org/10.5194/bg-21-1903-2024, 2024
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Determination of dissolved greenhouse gas (GHG) in freshwater allows us to estimate GHG fluxes. Mercuric chloride (HgCl2) is used to preserve water samples prior to GHG analysis despite its environmental and health impacts and interferences with water chemistry in freshwater. Here, we tested the effects of HgCl2, two substitutes and storage time on GHG in water from two boreal lakes. Preservation with HgCl2 caused overestimation of CO2 concentration with consequences for GHG flux estimation.
Helena Rautakoski, Mika Korkiakoski, Jarmo Mäkelä, Markku Koskinen, Kari Minkkinen, Mika Aurela, Paavo Ojanen, and Annalea Lohila
Biogeosciences, 21, 1867–1886, https://doi.org/10.5194/bg-21-1867-2024, https://doi.org/10.5194/bg-21-1867-2024, 2024
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Current and future nitrous oxide (N2O) emissions are difficult to estimate due to their high variability in space and time. Several years of N2O fluxes from drained boreal peatland forest indicate high importance of summer precipitation, winter temperature, and snow conditions in controlling annual N2O emissions. The results indicate increasing year-to-year variation in N2O emissions in changing climate with more extreme seasonal weather conditions.
Matthias Koschorreck, Norbert Kamjunke, Uta Koedel, Michael Rode, Claudia Schuetze, and Ingeborg Bussmann
Biogeosciences, 21, 1613–1628, https://doi.org/10.5194/bg-21-1613-2024, https://doi.org/10.5194/bg-21-1613-2024, 2024
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We measured the emission of carbon dioxide (CO2) and methane (CH4) from different sites at the river Elbe in Germany over 3 days to find out what is more important for quantification: small-scale spatial variability or diurnal temporal variability. We found that CO2 emissions were very different between day and night, while CH4 emissions were more different between sites. Dried out river sediments contributed to CO2 emissions, while the side areas of the river were important CH4 sources.
Odysseas Sifounakis, Edwin Haas, Klaus Butterbach-Bahl, and Maria P. Papadopoulou
Biogeosciences, 21, 1563–1581, https://doi.org/10.5194/bg-21-1563-2024, https://doi.org/10.5194/bg-21-1563-2024, 2024
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We performed a full assessment of the carbon and nitrogen cycles of a cropland ecosystem. An uncertainty analysis and quantification of all carbon and nitrogen fluxes were deployed. The inventory simulations include greenhouse gas emissions of N2O, NH3 volatilization and NO3 leaching from arable land cultivation in Greece. The inventory also reports changes in soil organic carbon and nitrogen stocks in arable soils.
Sarah M. Ludwig, Luke Schiferl, Jacqueline Hung, Susan M. Natali, and Roisin Commane
Biogeosciences, 21, 1301–1321, https://doi.org/10.5194/bg-21-1301-2024, https://doi.org/10.5194/bg-21-1301-2024, 2024
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Landscapes are often assumed to be homogeneous when using eddy covariance fluxes, which can lead to biases when calculating carbon budgets. In this study we report eddy covariance carbon fluxes from heterogeneous tundra. We used the footprints of each flux observation to unmix the fluxes coming from components of the landscape. We identified and quantified hot spots of carbon emissions in the landscape. Accurately scaling with landscape heterogeneity yielded half as much regional carbon uptake.
Justine Trémeau, Beñat Olascoaga, Leif Backman, Esko Karvinen, Henriikka Vekuri, and Liisa Kulmala
Biogeosciences, 21, 949–972, https://doi.org/10.5194/bg-21-949-2024, https://doi.org/10.5194/bg-21-949-2024, 2024
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We studied urban lawns and meadows in the Helsinki metropolitan area, Finland. We found that meadows are more resistant to drought events but that they do not increase carbon sequestration compared with lawns. Moreover, the transformation from lawns to meadows did not demonstrate any negative climate effects in terms of greenhouse gas emissions. Even though social and economic aspects also steer urban development, these results can guide planning to consider carbon-smart options.
Guantao Chen, Edzo Veldkamp, Muhammad Damris, Bambang Irawan, Aiyen Tjoa, and Marife D. Corre
Biogeosciences, 21, 513–529, https://doi.org/10.5194/bg-21-513-2024, https://doi.org/10.5194/bg-21-513-2024, 2024
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We established an oil palm management experiment in a large-scale oil palm plantation in Jambi, Indonesia. We recorded oil palm fruit yield and measured soil CO2, N2O, and CH4 fluxes. After 4 years of treatment, compared with conventional fertilization with herbicide weeding, reduced fertilization with mechanical weeding did not reduce yield and soil greenhouse gas emissions, which highlights the legacy effects of over a decade of conventional management prior to the start of the experiment.
Elizabeth Gachibu Wangari, Ricky Mwangada Mwanake, Tobias Houska, David Kraus, Gretchen Maria Gettel, Ralf Kiese, Lutz Breuer, and Klaus Butterbach-Bahl
Biogeosciences, 20, 5029–5067, https://doi.org/10.5194/bg-20-5029-2023, https://doi.org/10.5194/bg-20-5029-2023, 2023
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Agricultural landscapes act as sinks or sources of the greenhouse gases (GHGs) CO2, CH4, or N2O. Various physicochemical and biological processes control the fluxes of these GHGs between ecosystems and the atmosphere. Therefore, fluxes depend on environmental conditions such as soil moisture, soil temperature, or soil parameters, which result in large spatial and temporal variations of GHG fluxes. Here, we describe an example of how this variation may be studied and analyzed.
Merit van den Berg, Thomas Gremmen, Renske J. E. Vroom, Jacobus van Huissteden, Jim Boonman, Corine J. A. van Huissteden, Ype van der Velde, Alfons J. P. Smolders, and Bas P. van de Riet
EGUsphere, https://doi.org/10.5194/egusphere-2023-2826, https://doi.org/10.5194/egusphere-2023-2826, 2023
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Drained peatlands emit 3 % of the global greenhouse gas emission. Paludiculture is a way to reduce CO2 emissions while at the same time generating an income for landowners. The side effect is the potentially high methane emission. We found very high methane emission for broadleaf cattail, compared to narrowleaf cattail and water fern. The rewetting was, however, effective to stop CO2 emission for all species. The highest potential to reduce greenhouse gas emission had narrowleaf cattail.
Hella van Asperen, Thorsten Warneke, Alessandro Carioca de Araújo, Bruce Forsberg, Sávio José Filgueiras Ferreira, Thomas Röckmann, Carina van der Veen, Sipko Bulthuis, Leonardo Ramos de Oliveira, Thiago de Lima Xavier, Jailson da Mata, Marta de Oliveira Sá, Paulo Ricardo Teixeira, Julie Andrews de França e Silva, Susan Trumbore, and Justus Notholt
EGUsphere, https://doi.org/10.5194/egusphere-2023-2746, https://doi.org/10.5194/egusphere-2023-2746, 2023
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Carbon monoxide (CO) is considered an important indirect greenhouse gas. Soils can emit as well as take up CO but, until now, uncertainty remains which process dominates in tropical rain forests. We present the first soil CO flux measurements from a tropical rain forest. Based on our observations, we report that tropical rain forest soils are a net source of CO. In addition, we show that valley streams and inundated areas are likely additional hot spots of CO in the ecosystem.
Colette L. Kelly, Nicole M. Travis, Pascale A. Baya, Claudia Frey, Xin Sun, Bess B. Ward, and Karen L. Casciotti
EGUsphere, https://doi.org/10.5194/egusphere-2023-2642, https://doi.org/10.5194/egusphere-2023-2642, 2023
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We investigated the origins of nitrous oxide, a potent greenhouse gas, in low oxygen ocean regions. Our findings shed light on the microbial processes behind nitrous oxide production, including “hybrid” nitrous oxide generation by ammonia-oxidizing archaea, one of the most abundant organisms in the ocean. We also observed a strong link between nitrous oxide production and oxygen levels. These results set up potential feedbacks between oxygen depletion and greenhouse gas cycling in the oceans.
Laurie C. Menviel, Paul Spence, Andrew E. Kiss, Matthew A. Chamberlain, Hakase Hayashida, Matthew H. England, and Darryn Waugh
Biogeosciences, 20, 4413–4431, https://doi.org/10.5194/bg-20-4413-2023, https://doi.org/10.5194/bg-20-4413-2023, 2023
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As the ocean absorbs 25% of the anthropogenic emissions of carbon, it is important to understand the impact of climate change on the flux of carbon between the ocean and the atmosphere. Here, we use a very high-resolution ocean, sea-ice, carbon cycle model to show that the capability of the Southern Ocean to uptake CO2 has decreased over the last 40 years due to a strengthening and poleward shift of the southern hemispheric westerlies. This trend is expected to continue over the coming century.
Yélognissè Agbohessou, Claire Delon, Manuela Grippa, Eric Mougin, Daouda Ngom, Espoir Koudjo Gaglo, Ousmane Ndiaye, Paulo Salgado, and Olivier Roupsard
EGUsphere, https://doi.org/10.5194/egusphere-2023-2452, https://doi.org/10.5194/egusphere-2023-2452, 2023
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Emissions of greenhouse gases in the Sahel are not well represented, because considered as weak compared to the rest of the world. However, natural areas in the Sahel emit carbon dioxide and nitrous oxides which need to be assessed because of extended surfaces. We propose an assessment of such emissions in Sahelian silvopastoral systems, and how they are influenced by environmental characteristics. These results are essential to inform on climate change strategies in the region.
Petr Znachor, Jiří Nedoma, Vojtech Kolar, and Anna Matoušů
Biogeosciences, 20, 4273–4288, https://doi.org/10.5194/bg-20-4273-2023, https://doi.org/10.5194/bg-20-4273-2023, 2023
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We conducted intensive spatial sampling of the hypertrophic fishpond to better understand the spatial dynamics of methane fluxes and environmental heterogeneity in fishponds. The diffusive fluxes of methane accounted for only a minor fraction of the total fluxes and both varied pronouncedly within the pond and over the studied summer season. This could be explained only by the water depth. Wind substantially affected temperature, oxygen and chlorophyll a distribution in the pond.
Sofie Sjögersten, Martha Ledger, Matthias Siewert, Betsabé de la Barreda-Bautista, Andrew Sowter, David Gee, Giles Foody, and Doreen S. Boyd
Biogeosciences, 20, 4221–4239, https://doi.org/10.5194/bg-20-4221-2023, https://doi.org/10.5194/bg-20-4221-2023, 2023
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Permafrost thaw in Arctic regions is increasing methane emissions, but quantification is difficult given the large and remote areas impacted. We show that UAV data together with satellite data can be used to extrapolate emissions across the wider landscape as well as detect areas at risk of higher emissions. A transition of currently degrading areas to fen type vegetation can increase emission by several orders of magnitude, highlighting the importance of quantifying areas at risk.
Cole G. Brachmann, Tage Vowles, Riikka Rinnan, Mats P. Björkman, Anna Ekberg, and Robert G. Björk
Biogeosciences, 20, 4069–4086, https://doi.org/10.5194/bg-20-4069-2023, https://doi.org/10.5194/bg-20-4069-2023, 2023
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Herbivores change plant communities through grazing, altering the amount of CO2 and plant-specific chemicals (termed VOCs) emitted. We tested this effect by excluding herbivores and studying the CO2 and VOC emissions. Herbivores reduced CO2 emissions from a meadow community and altered VOC composition; however, community type had the strongest effect on the amount of CO2 and VOCs released. Herbivores can mediate greenhouse gas emissions, but the effect is marginal and community dependent.
Ole Lessmann, Jorge Encinas Fernández, Karla Martínez-Cruz, and Frank Peeters
Biogeosciences, 20, 4057–4068, https://doi.org/10.5194/bg-20-4057-2023, https://doi.org/10.5194/bg-20-4057-2023, 2023
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Based on a large dataset of seasonally resolved methane (CH4) pore water concentrations in a reservoir's sediment, we assess the significance of CH4 emissions due to reservoir flushing. In the studied reservoir, CH4 emissions caused by one flushing operation can represent 7 %–14 % of the annual CH4 emissions and depend on the timing of the flushing operation. In reservoirs with high sediment loadings, regular flushing may substantially contribute to the overall CH4 emissions.
Matti Räsänen, Risto Vesala, Petri Rönnholm, Laura Arppe, Petra Manninen, Markus Jylhä, Jouko Rikkinen, Petri Pellikka, and Janne Rinne
Biogeosciences, 20, 4029–4042, https://doi.org/10.5194/bg-20-4029-2023, https://doi.org/10.5194/bg-20-4029-2023, 2023
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Fungus-growing termites recycle large parts of dead plant material in African savannas and are significant sources of greenhouse gases. We measured CO2 and CH4 fluxes from their mounds and surrounding soils in open and closed habitats. The fluxes scale with mound volume. The results show that emissions from mounds of fungus-growing termites are more stable than those from other termites. The soil fluxes around the mound are affected by the termite colonies at up to 2 m distance from the mound.
Tim René de Groot, Anne Margriet Mol, Katherine Mesdag, Pierre Ramond, Rachel Ndhlovu, Julia Catherine Engelmann, Thomas Röckmann, and Helge Niemann
Biogeosciences, 20, 3857–3872, https://doi.org/10.5194/bg-20-3857-2023, https://doi.org/10.5194/bg-20-3857-2023, 2023
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This study investigates methane dynamics in the Wadden Sea. Our measurements revealed distinct variations triggered by seasonality and tidal forcing. The methane budget was higher in warmer seasons but surprisingly high in colder seasons. Methane dynamics were amplified during low tides, flushing the majority of methane into the North Sea or releasing it to the atmosphere. Methanotrophic activity was also elevated during low tide but mitigated only a small fraction of the methane efflux.
Frederic Thalasso, Brenda Riquelme, Andrés Gómez, Roy Mackenzie, Francisco Javier Aguirre, Jorge Hoyos-Santillan, Ricardo Rozzi, and Armando Sepulveda-Jauregui
Biogeosciences, 20, 3737–3749, https://doi.org/10.5194/bg-20-3737-2023, https://doi.org/10.5194/bg-20-3737-2023, 2023
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A robust skirt-chamber design to capture and quantify greenhouse gas emissions from peatlands is presented. Compared to standard methods, this design improves the spatial resolution of field studies in remote locations while minimizing intrusion.
Gesa Schulz, Tina Sanders, Yoana G. Voynova, Hermann W. Bange, and Kirstin Dähnke
Biogeosciences, 20, 3229–3247, https://doi.org/10.5194/bg-20-3229-2023, https://doi.org/10.5194/bg-20-3229-2023, 2023
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Nitrous oxide (N2O) is an important greenhouse gas. However, N2O emissions from estuaries underlie significant uncertainties due to limited data availability and high spatiotemporal variability. We found the Elbe Estuary (Germany) to be a year-round source of N2O, with the highest emissions in winter along with high nitrogen loads. However, in spring and summer, N2O emissions did not decrease alongside lower nitrogen loads because organic matter fueled in situ N2O production along the estuary.
Alex Mavrovic, Oliver Sonnentag, Juha Lemmetyinen, Jennifer L. Baltzer, Christophe Kinnard, and Alexandre Roy
Biogeosciences, 20, 2941–2970, https://doi.org/10.5194/bg-20-2941-2023, https://doi.org/10.5194/bg-20-2941-2023, 2023
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This review supports the integration of microwave spaceborne information into carbon cycle science for Arctic–boreal regions. The microwave data record spans multiple decades with frequent global observations of soil moisture and temperature, surface freeze–thaw cycles, vegetation water storage, snowpack properties, and land cover. This record holds substantial unexploited potential to better understand carbon cycle processes.
Zoé Rehder, Thomas Kleinen, Lars Kutzbach, Victor Stepanenko, Moritz Langer, and Victor Brovkin
Biogeosciences, 20, 2837–2855, https://doi.org/10.5194/bg-20-2837-2023, https://doi.org/10.5194/bg-20-2837-2023, 2023
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We use a new model to investigate how methane emissions from Arctic ponds change with warming. We find that emissions increase substantially. Under annual temperatures 5 °C above present temperatures, pond methane emissions are more than 3 times higher than now. Most of this increase is caused by an increase in plant productivity as plants provide the substrate microbes used to produce methane. We conclude that vegetation changes need to be included in predictions of pond methane emissions.
Julian Koch, Lars Elsgaard, Mogens H. Greve, Steen Gyldenkærne, Cecilie Hermansen, Gregor Levin, Shubiao Wu, and Simon Stisen
Biogeosciences, 20, 2387–2403, https://doi.org/10.5194/bg-20-2387-2023, https://doi.org/10.5194/bg-20-2387-2023, 2023
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Utilizing peatlands for agriculture leads to large emissions of greenhouse gases worldwide. The emissions are triggered by lowering the water table, which is a necessary step in order to make peatlands arable. Many countries aim at reducing their emissions by restoring peatlands, which can be achieved by stopping agricultural activities and thereby raising the water table. We estimate a total emission of 2.6 Mt CO2-eq for organic-rich peatlands in Denmark and a potential reduction of 77 %.
Mélissa Laurent, Matthias Fuchs, Tanja Herbst, Alexandra Runge, Susanne Liebner, and Claire C. Treat
Biogeosciences, 20, 2049–2064, https://doi.org/10.5194/bg-20-2049-2023, https://doi.org/10.5194/bg-20-2049-2023, 2023
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In this study we investigated the effect of different parameters (temperature, landscape position) on the production of greenhouse gases during a 1-year permafrost thaw experiment. For very similar carbon and nitrogen contents, our results show a strong heterogeneity in CH4 production, as well as in microbial abundance. According to our study, these differences are mainly due to the landscape position and the hydrological conditions established as a result of the topography.
Michael Moubarak, Seeta Sistla, Stefano Potter, Susan M. Natali, and Brendan M. Rogers
Biogeosciences, 20, 1537–1557, https://doi.org/10.5194/bg-20-1537-2023, https://doi.org/10.5194/bg-20-1537-2023, 2023
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Tundra wildfires are increasing in frequency and severity with climate change. We show using a combination of field measurements and computational modeling that tundra wildfires result in a positive feedback to climate change by emitting significant amounts of long-lived greenhouse gasses. With these effects, attention to tundra fires is necessary for mitigating climate change.
Hanna I. Campen, Damian L. Arévalo-Martínez, and Hermann W. Bange
Biogeosciences, 20, 1371–1379, https://doi.org/10.5194/bg-20-1371-2023, https://doi.org/10.5194/bg-20-1371-2023, 2023
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Carbon monoxide (CO) is a climate-relevant trace gas emitted from the ocean. However, oceanic CO cycling is understudied. Results from incubation experiments conducted in the Fram Strait (Arctic Ocean) indicated that (i) pH did not affect CO cycling and (ii) enhanced CO production and consumption were positively correlated with coloured dissolved organic matter and nitrate concentrations. This suggests microbial CO uptake to be the driving factor for CO cycling in the Arctic Ocean.
Yihong Zhu, Ruihua Liu, Huai Zhang, Shaoda Liu, Zhengfeng Zhang, Fei-Hai Yu, and Timothy G. Gregoire
Biogeosciences, 20, 1357–1370, https://doi.org/10.5194/bg-20-1357-2023, https://doi.org/10.5194/bg-20-1357-2023, 2023
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With global warming, the risk of flooding is rising, but the response of the carbon cycle of aquatic and associated riparian systems
to flooding is still unclear. Based on the data collected in the Lijiang, we found that flooding would lead to significant carbon emissions of fluvial areas and riparian areas during flooding, but carbon capture may happen after flooding. In the riparian areas, the surviving vegetation, especially clonal plants, played a vital role in this transformation.
Lauri Heiskanen, Juha-Pekka Tuovinen, Henriikka Vekuri, Aleksi Räsänen, Tarmo Virtanen, Sari Juutinen, Annalea Lohila, Juha Mikola, and Mika Aurela
Biogeosciences, 20, 545–572, https://doi.org/10.5194/bg-20-545-2023, https://doi.org/10.5194/bg-20-545-2023, 2023
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We measured and modelled the CO2 and CH4 fluxes of the terrestrial and aquatic ecosystems of the subarctic landscape for 2 years. The landscape was an annual CO2 sink and a CH4 source. The forest had the largest contribution to the landscape-level CO2 sink and the peatland to the CH4 emissions. The lakes released 24 % of the annual net C uptake of the landscape back to the atmosphere. The C fluxes were affected most by the rainy peak growing season of 2017 and the drought event in July 2018.
Artem G. Lim, Ivan V. Krickov, Sergey N. Vorobyev, Mikhail A. Korets, Sergey Kopysov, Liudmila S. Shirokova, Jan Karlsson, and Oleg S. Pokrovsky
Biogeosciences, 19, 5859–5877, https://doi.org/10.5194/bg-19-5859-2022, https://doi.org/10.5194/bg-19-5859-2022, 2022
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In order to quantify C transport and emission and main environmental factors controlling the C cycle in Siberian rivers, we investigated the largest tributary of the Ob River, the Ket River basin, by measuring spatial and seasonal variations in carbon CO2 and CH4 concentrations and emissions together with hydrochemical analyses. The obtained results are useful for large-scale modeling of C emission and export fluxes from permafrost-free boreal rivers of an underrepresented region of the world.
Robert J. Parker, Chris Wilson, Edward Comyn-Platt, Garry Hayman, Toby R. Marthews, A. Anthony Bloom, Mark F. Lunt, Nicola Gedney, Simon J. Dadson, Joe McNorton, Neil Humpage, Hartmut Boesch, Martyn P. Chipperfield, Paul I. Palmer, and Dai Yamazaki
Biogeosciences, 19, 5779–5805, https://doi.org/10.5194/bg-19-5779-2022, https://doi.org/10.5194/bg-19-5779-2022, 2022
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Wetlands are the largest natural source of methane, one of the most important climate gases. The JULES land surface model simulates these emissions. We use satellite data to evaluate how well JULES reproduces the methane seasonal cycle over different tropical wetlands. It performs well for most regions; however, it struggles for some African wetlands influenced heavily by river flooding. We explain the reasons for these deficiencies and highlight how future development will improve these areas.
Saúl Edgardo Martínez Castellón, José Henrique Cattanio, José Francisco Berrêdo, Marcelo Rollnic, Maria de Lourdes Ruivo, and Carlos Noriega
Biogeosciences, 19, 5483–5497, https://doi.org/10.5194/bg-19-5483-2022, https://doi.org/10.5194/bg-19-5483-2022, 2022
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We seek to understand the influence of climatic seasonality and microtopography on CO2 and CH4 fluxes in an Amazonian mangrove. Topography and seasonality had a contrasting influence when comparing the two gas fluxes: CO2 fluxes were greater in high topography in the dry period, and CH4 fluxes were greater in the rainy season in low topography. Only CO2 fluxes were correlated with soil organic matter, the proportion of carbon and nitrogen, and redox potential.
Matthias Koschorreck, Klaus Holger Knorr, and Lelaina Teichert
Biogeosciences, 19, 5221–5236, https://doi.org/10.5194/bg-19-5221-2022, https://doi.org/10.5194/bg-19-5221-2022, 2022
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At low water levels, parts of the bottom of rivers fall dry. These beaches or mudflats emit the greenhouse gas carbon dioxide (CO2) to the atmosphere. We found that those emissions are caused by microbial reactions in the sediment and that they change with time. Emissions were influenced by many factors like temperature, water level, rain, plants, and light.
Wantong Zhang, Zhengyi Hu, Joachim Audet, Thomas A. Davidson, Enze Kang, Xiaoming Kang, Yong Li, Xiaodong Zhang, and Jinzhi Wang
Biogeosciences, 19, 5187–5197, https://doi.org/10.5194/bg-19-5187-2022, https://doi.org/10.5194/bg-19-5187-2022, 2022
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This work focused on the CH4 and N2O emissions from alpine peatlands in response to the interactive effects of altered water table levels and increased nitrogen deposition. Across the 2-year mesocosm experiment, nitrogen deposition showed nonlinear effects on CH4 emissions and linear effects on N2O emissions, and these N effects were associated with the water table levels. Our results imply the future scenario of strengthened CH4 and N2O emissions from an alpine peatland.
Karel Castro-Morales, Anna Canning, Sophie Arzberger, Will A. Overholt, Kirsten Küsel, Olaf Kolle, Mathias Göckede, Nikita Zimov, and Arne Körtzinger
Biogeosciences, 19, 5059–5077, https://doi.org/10.5194/bg-19-5059-2022, https://doi.org/10.5194/bg-19-5059-2022, 2022
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Permafrost thaw releases methane that can be emitted into the atmosphere or transported by Arctic rivers. Methane measurements are lacking in large Arctic river regions. In the Kolyma River (northeast Siberia), we measured dissolved methane to map its distribution with great spatial detail. The river’s edge and river junctions had the highest methane concentrations compared to other river areas. Microbial communities in the river showed that the river’s methane likely is from the adjacent land.
Sonja Gindorf, Hermann W. Bange, Dennis Booge, and Annette Kock
Biogeosciences, 19, 4993–5006, https://doi.org/10.5194/bg-19-4993-2022, https://doi.org/10.5194/bg-19-4993-2022, 2022
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Methane is a climate-relevant greenhouse gas which is emitted to the atmosphere from coastal areas such as the Baltic Sea. We measured the methane concentration in the water column of the western Kiel Bight. Methane concentrations were higher in September than in June. We found no relationship between the 2018 European heatwave and methane concentrations. Our results show that the methane distribution in the water column is strongly affected by temporal and spatial variabilities.
Margaret Capooci and Rodrigo Vargas
Biogeosciences, 19, 4655–4670, https://doi.org/10.5194/bg-19-4655-2022, https://doi.org/10.5194/bg-19-4655-2022, 2022
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Tidal salt marsh soil emits greenhouse gases, as well as sulfur-based gases, which play roles in global climate but are not well studied as they are difficult to measure. Traditional methods of measuring these gases worked relatively well for carbon dioxide, but less so for methane, nitrous oxide, carbon disulfide, and dimethylsulfide. High variability of trace gases complicates the ability to accurately calculate gas budgets and new approaches are needed for monitoring protocols.
Janne Rinne, Patryk Łakomiec, Patrik Vestin, Joel D. White, Per Weslien, Julia Kelly, Natascha Kljun, Lena Ström, and Leif Klemedtsson
Biogeosciences, 19, 4331–4349, https://doi.org/10.5194/bg-19-4331-2022, https://doi.org/10.5194/bg-19-4331-2022, 2022
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The study uses the stable isotope 13C of carbon in methane to investigate the origins of spatial and temporal variation in methane emitted by a temperate wetland ecosystem. The results indicate that methane production is more important for spatial variation than methane consumption by micro-organisms. Temporal variation on a seasonal timescale is most likely affected by more than one driver simultaneously.
Kukka-Maaria Kohonen, Roderick Dewar, Gianluca Tramontana, Aleksanteri Mauranen, Pasi Kolari, Linda M. J. Kooijmans, Dario Papale, Timo Vesala, and Ivan Mammarella
Biogeosciences, 19, 4067–4088, https://doi.org/10.5194/bg-19-4067-2022, https://doi.org/10.5194/bg-19-4067-2022, 2022
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Four different methods for quantifying photosynthesis (GPP) at ecosystem scale were tested, of which two are based on carbon dioxide (CO2) and two on carbonyl sulfide (COS) flux measurements. CO2-based methods are traditional partitioning, and a new method uses machine learning. We introduce a novel method for calculating GPP from COS fluxes, with potentially better applicability than the former methods. Both COS-based methods gave on average higher GPP estimates than the CO2-based estimates.
Lutz Beckebanze, Benjamin R. K. Runkle, Josefine Walz, Christian Wille, David Holl, Manuel Helbig, Julia Boike, Torsten Sachs, and Lars Kutzbach
Biogeosciences, 19, 3863–3876, https://doi.org/10.5194/bg-19-3863-2022, https://doi.org/10.5194/bg-19-3863-2022, 2022
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In this study, we present observations of lateral and vertical carbon fluxes from a permafrost-affected study site in the Russian Arctic. From this dataset we estimate the net ecosystem carbon balance for this study site. We show that lateral carbon export has a low impact on the net ecosystem carbon balance during the complete study period (3 months). Nevertheless, our results also show that lateral carbon export can exceed vertical carbon uptake at the beginning of the growing season.
Shahar Baram, Asher Bar-Tal, Alon Gal, Shmulik P. Friedman, and David Russo
Biogeosciences, 19, 3699–3711, https://doi.org/10.5194/bg-19-3699-2022, https://doi.org/10.5194/bg-19-3699-2022, 2022
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Static chambers are the most common tool used to measure greenhouse gas (GHG) fluxes. We tested the impact of such chambers on nitrous oxide emissions in drip irrigation. Field measurements and 3-D simulations show that the chamber base drastically affects the water and nutrient distribution in the soil and hence the measured GHG fluxes. A nomogram is suggested to determine the optimal diameter of a cylindrical chamber that ensures minimal disturbance.
Tracy E. Rankin, Nigel T. Roulet, and Tim R. Moore
Biogeosciences, 19, 3285–3303, https://doi.org/10.5194/bg-19-3285-2022, https://doi.org/10.5194/bg-19-3285-2022, 2022
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Peatland respiration is made up of plant and peat sources. How to separate these sources is not well known as peat respiration is not straightforward and is more influenced by vegetation dynamics than previously thought. Results of plot level measurements from shrubs and sparse grasses in a woody bog show that plants' respiration response to changes in climate is related to their different root structures, implying a difference in the mechanisms by which they obtain water resources.
Alison Bressler and Jennifer Blesh
Biogeosciences, 19, 3169–3184, https://doi.org/10.5194/bg-19-3169-2022, https://doi.org/10.5194/bg-19-3169-2022, 2022
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Our field experiment tested if a mixture of a nitrogen-fixing legume and non-legume cover crop could reduce nitrous oxide (N2O) emissions following tillage, compared to the legume grown alone. We found higher N2O following both legume treatments, compared to those without, and lower emissions from the cover crop mixture at one of the two test sites, suggesting that interactions between cover crop types and soil quality influence N2O emissions.
Sari Juutinen, Mika Aurela, Juha-Pekka Tuovinen, Viktor Ivakhov, Maiju Linkosalmi, Aleksi Räsänen, Tarmo Virtanen, Juha Mikola, Johanna Nyman, Emmi Vähä, Marina Loskutova, Alexander Makshtas, and Tuomas Laurila
Biogeosciences, 19, 3151–3167, https://doi.org/10.5194/bg-19-3151-2022, https://doi.org/10.5194/bg-19-3151-2022, 2022
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We measured CO2 and CH4 fluxes in heterogenous Arctic tundra in eastern Siberia. We found that tundra wetlands with sedge and grass vegetation contributed disproportionately to the landscape's ecosystem CO2 uptake and CH4 emissions to the atmosphere. Moreover, we observed high CH4 consumption in dry tundra, particularly in barren areas, offsetting part of the CH4 emissions from the wetlands.
Jessica Plein, Rulon W. Clark, Kyle A. Arndt, Walter C. Oechel, Douglas Stow, and Donatella Zona
Biogeosciences, 19, 2779–2794, https://doi.org/10.5194/bg-19-2779-2022, https://doi.org/10.5194/bg-19-2779-2022, 2022
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Tundra vegetation and the carbon balance of Arctic ecosystems can be substantially impacted by herbivory. We tested how herbivory by brown lemmings in individual enclosure plots have impacted carbon exchange of tundra ecosystems via altering carbon dioxide (CO2) and methane (CH4) fluxes. Lemmings significantly decreased net CO2 uptake while not affecting CH4 emissions. There was no significant difference in the subsequent growing season due to recovery of the vegetation.
Jenie Gil, Maija E. Marushchak, Tobias Rütting, Elizabeth M. Baggs, Tibisay Pérez, Alexander Novakovskiy, Tatiana Trubnikova, Dmitry Kaverin, Pertti J. Martikainen, and Christina Biasi
Biogeosciences, 19, 2683–2698, https://doi.org/10.5194/bg-19-2683-2022, https://doi.org/10.5194/bg-19-2683-2022, 2022
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N2O emissions from permafrost soils represent up to 11.6 % of total N2O emissions from natural soils, and their contribution to the global N2O budget will likely increase due to climate change. A better understanding of N2O production from permafrost soil is needed to evaluate the role of arctic ecosystems in the global N2O budget. By studying microbial N2O production processes in N2O hotspots in permafrost peatlands, we identified denitrification as the dominant source of N2O in these surfaces.
Christian Rödenbeck, Tim DeVries, Judith Hauck, Corinne Le Quéré, and Ralph F. Keeling
Biogeosciences, 19, 2627–2652, https://doi.org/10.5194/bg-19-2627-2022, https://doi.org/10.5194/bg-19-2627-2022, 2022
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The ocean is an important part of the global carbon cycle, taking up about a quarter of the anthropogenic CO2 emitted by burning of fossil fuels and thus slowing down climate change. However, the CO2 uptake by the ocean is, in turn, affected by variability and trends in climate. Here we use carbon measurements in the surface ocean to quantify the response of the oceanic CO2 exchange to environmental conditions and discuss possible mechanisms underlying this response.
Shuang Ma, Lifen Jiang, Rachel M. Wilson, Jeff P. Chanton, Scott Bridgham, Shuli Niu, Colleen M. Iversen, Avni Malhotra, Jiang Jiang, Xingjie Lu, Yuanyuan Huang, Jason Keller, Xiaofeng Xu, Daniel M. Ricciuto, Paul J. Hanson, and Yiqi Luo
Biogeosciences, 19, 2245–2262, https://doi.org/10.5194/bg-19-2245-2022, https://doi.org/10.5194/bg-19-2245-2022, 2022
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The relative ratio of wetland methane (CH4) emission pathways determines how much CH4 is oxidized before leaving the soil. We found an ebullition modeling approach that has a better performance in deep layer pore water CH4 concentration. We suggest using this approach in land surface models to accurately represent CH4 emission dynamics and response to climate change. Our results also highlight that both CH4 flux and belowground concentration data are important to constrain model parameters.
Cited articles
ACIA: Impacts of a Warming Arctic: Arctic Climate Impact Assessment, Cambridge University Press, Cambridge, 139 pp., 2004.
Alling, V., Sánchez-García, L., Porcelli, D., Pugach, S., Vonk, J., van Dongen, B., Mörth, C. M., Anderson, L. G., Sokolov, A., Andersson, P., Humborg, C., Semiletov, I., and Gustafsson, Ö.: Nonconservative behavior of dissolved organic carbon across the Laptev and East Siberian seas, Global Biogeochem. Cy., 24, GB4033, https://doi.org/10.1029/2010GB003834, 2010.
AMAP: Snow, Water, Ice and Permafrost in the Arctic (SWIPA): Climate Change and the Cryosphere. Arctic Monitoring and Assessment Programme (AMAP), Oslo, Norway, 538 pp., 2012.
Amon, R. M. W. and Benner, R.: Bacterial utilization of different size classes of dissolved organic matter, Limnol. Oceanogr., 41, 41–51, 1996a.
Amon, R. M. W. and Benner, R.: Photochemical and microbial consumption of dissolved organic carbon and dissolved oxygen in the Amazon River system, Geochim. Cosmochim. Ac., 60, 10, 1783–1792, 1996b.
Anderson, L. G., Jutterström, S., Hjalmarsson, S., Wahlström, I., and Semiletov, I.: Out-gassing of CO2 from Siberian Shelf seas by terrestrial organic matter decomposition, Geophys. Res. Lett., 36, L20601, https://doi.org/10.1029/2009GL040046, 2009.
Anderson, L. G., Björk, G., Jutterström, S., Pipko, I., Shakhova, N., Semiletov, I., and Wåhlström, I.: East Siberian Sea, an Arctic region of very high biogeochemical activity, Biogeosciences, 8, 1745–1754, https://doi.org/10.5194/bg-8-1745-2011, 2011.
Arrigo, K. R. and van Dijken, G.: Secular trends in Arctic Ocean net primary production, J. Geophys. Res., 116, C09011, https://doi.org/10.1029/2011JC007151, 2011.
Belzile, C. C., Roesler, S., Christensen, J. P., Shakhova, N., and Semiletov, I.: Fluorescence measured using the WETStar DOM fluorometer as a proxy for dissolved matter absorption, Estuar. Coast. Shelf Sci., 67, 41–49, 2006.
Boucsein, B., Fahl, K., and Stein, R.: Variability of river discharge and Atlantic-water inflow at the Laptev Sea continental margin during the past 15,000 years: Implications from maceral and biomarker records, Int. J. Earth Sci., 89, 578–591, 2000.
Bruevich, S. V.: Instruction for Chemical Investigation of Seawater, Glavsevmorput, Moscow, 83 pp., 1944 (in Russian).
Canadell, J. G. and Raupach, M. R.: Land carbon cycle feedbacks, in: Sommerkorn, M. and Hassol, S. J. (Eds.): Arctic Climate Feedbacks: Global Implications, WWF International Arctic Programme, Oslo, 70–80, 2009.
Charkin, A. N., Dudarev, O. V., Semiletov, I. P., Kruhmalev, A. V., Vonk, J. E., Sánchez-García, L., Karlsson, E., and Gustafsson, Ö.: Seasonal and interannual variability of sedimentation and organic matter distribution in the Buor-Khaya Gulf: the primary recipient of input from Lena River and coastal erosion in the southeast Laptev Sea, Biogeosciences, 8, 2581–2594, https://doi.org/10.5194/bg-8-2581-2011, 2011.
Cooke, M. P., van Dongen, B., Talbot, H., Semiletov, I., Shakhova, N., Guo, L., and Gustafsson, Ö.: Bacteriohopanepolyol biomarker composition of organic matter exported to the Arctic Ocean by seven of the major Arctic rivers, Org. Geochem., 40, 1151–1159, https://doi.org/10.1016/j.orggeochem.2009.07.014, 2009.
Cooper, L. W., Benner, R., McClelland, J. W., Peterson, B. J., Holmes, R. M., Raymond, P. A., Hansell, D. A., Grebmeier, J. M., and Codispoti, L. A.: Linkages among runoff, dissolved organic carbon, and the stable oxygen isotope composition of seawater and other water mass indicators in the Arctic Ocean, J. Geophys. Res., 110, G02013, https://doi.org/10.1029/2005JG000031, 2005.
Dickson, A. G. and Millero, F. J.: A comparison of the equilibrium constants for the dissociation of carbonic acid in seawater media, Deep-Sea Res., 34, 1733–1743, 1987.
Dittmar, T. and Kattner, G.: The biogeochemistry of the river and shelf ecosystem of the Arctic Ocean: A review, Mar. Chem., 83, 103–120, 2003.
DOE: Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water, Version 2, edited by: Dickson, A. G. and Goyet, C., 1994.
Dudarev, O., Semiletov, I., Botsul, A., and Charkin, A.: Modern sedimentation in the coastal cryolithozone of the Dmitry Laptev Strait/East-Siberian Sea, Russ. J. Pac. Geol., 22, 51–60, 2003 (translated into English).
Dudarev, O. V., Semiletov, I. P., and Charkin, A. N.: Particulate material composition in the Lena River-Laptev Sea system: scales of heterogeneities, Dokl. Earth Sci., 411, 1445–1451, 2006.
Feng, X., Vonk, J. E., van Dongen, B. E., Gustafsson, O., Semiletov, I. P., Dudarev, O. V., Wangh, Z., Montlucon, D. B., Wackeri, L., and Eglinton, T. I.: Differential mobilization of terrestrial carbon pools in Eurasian Arctic river basins, P. Natl. Acad. Sci. USA, 110, 14168–14173, https://doi.org/10.1073/pnas.1307031110, 2013.
Fichot, C. G., Kaiser, K., Hooker, S. B., Amon, R. M. W., Babin, M., Bélanger, S., Walker, S. A., and Benner, R.: Pan-Arctic distributions of continental runoff in the Arctic Ocean, Sci. Rep. 3, 1053, https://doi.org/10.1038/srep01053, 2013.
Freeman, C., Evans, C. D., Monteith, D. T., Reynolds, B., and Fenner, N.: Export of organic carbon from peat soils, Nature, 412, 785, https://doi.org/10.1038/35090628, 2001.
Goñi, M. A., Yunker, M. B., Macdonald, R. W., and Eglinton, T. I.: The supply and preservation of ancient and modern components of organic carbon in the Canadian Beaufort Shelf of the Arctic Ocean, Mar. Chem., 93, 53–73, 2005.
Gordeev, V. V., Martin, J. M., Sidorov, I. S., and Sidorova, M. V.: A reassessment of the Eurasian river input of water, sediment, major elements, and nutrients to the Arctic Ocean, Am. J. Sci., 296, 664–691, 1996.
Grigoriev, M. N.: Criomorphogenesis of the mouth area of the Lena River, Yakutsk, Institute of Permafrost Study of the Siberian Branch of the Russian Academy of Science, 1–176, 1993 (in Russian).
Grigoriev, M. N.: Cryomorphogenesis and Lithodynamics of the Coastal-shelf Zone of the Seas of Eastern Siberia. PhD thesis, Yakutsk Melnikov Permafrost Inst., 40 pp., 2008 (in Russian).
Grigoriev, M. N. and Kunitsky, V. V.: Destruction of the sea coastal ice-complex in Yakutia, in: Hydrometeorological and Biogeochemical Research in the Arctic, Proc. Arctic Regional Center, 2, edited by: Semiletov, I. P., Dal'nauka Press, Vladivostok, 109–116, 2000 (in Russian).
Grigoriev, M. N., Razumov, S. O., Kunitzkiy, V. V., and Spektor, V. B.: Dynamics of the Russian East Arctic Sea coast: Major factors, regularities and tendencies, Earth's Cryosphere, X, 74–94, 2006 (in Russian).
Gruber, N., Friedlingstein, P., Field, C. B., Valentini, R., Heimann, M., Richey, C. B., Romero-Lankao, P., Schulze, D., and Chen, C.-T. A.: The vulnerability of the carbon cycle in the 21st century: An assessment of carbon-climate-human interactions, in: The Global Carbon Cycle: Integrating Humans, Climate, and the Natural World, edited by: Field, C. B. and Raupach, M. R., Island Press, Washington, DC, 45–76, 2004.
Guo, L., Semiletov, I., Gustafsson, Ö., Ingri, J., Andersson, P., Dudarev, O., and White, D.: Characterization of Siberian Arctic coastal sediments: Implications for terrestrial organic carbon export, Global Biogeochem. Cy., 18, GB1036, https://doi.org/10.1029/2003GB002087, 2004.
Gustafsson, Ö., Haghseta, F., Chan, C., MacFarlane, J., and Gschwend, P. M.: Quantification of the dilute sedimentary soot phase: Implications for PAH speciation and bioavailability, Environ. Sci. Technol., 31, 203–209, 1997.
Gustafsson, Ö., van Dongen, B. E., Vonk, J. E., Dudarev, O. V., and Semiletov, I. P.: Widespread release of old carbon across the Siberian Arctic echoed by its large rivers, Biogeosciences, 8, 1737–1743, https://doi.org/10.5194/bg-8-1737-2011, 2011.
Haraldsson, C., Anderson, L. G., Hassellov, M., Hulth, S., and Olsson, K.: Rapid, high-precision potentiometric titration of alkalinity in ocean and sediment pore waters, Deep-Sea Res. Pt. I, 44, 2031–2044, 1997.
Heim, B., Abramova, E., Doerffer, R., Günther, F., Hölemann, J., Kraberg, A., Lantuit, H., Loginova, A., Martynov, F., Overduin, P. P., and Wegner, C.: Ocean Colour remote sensing in the Southern Laptev Sea: evaluation and applications, Biogeosciences Discuss., 10, 3849–3889, https://doi.org/10.5194/bgd-10-3849-2013, 2013.
Holemann, J., Kirillov, S., Klagge, T., Novikhin, A., Kassens, H., and Timokhov, L.: Near-bottom water warming in the Laptev Sea in response to atmospheric sea-ice conditions in 2007, Polar Res., 30, 6425–6440, 2011.
Holmes, R. M., Peterson, B. J., Zhulidov, A. V., Gordeev, V. V., Makkaveev, P. N., Stunzas, P. A., Kosmenko, L. S., Kohler, G. H., Shiklomanov, A. I.: Nutrient chemistry of the Ob' and Yenisey rivers, Siberia: results from June 2000 expedition and evaluation of long-term data sets, Mar. Chem., 75, 219–227, 2001.
Holmes, R. M., McClelland, J. W., Raymond, P. A., Franzer, B. B., Peterson, B. J., and Stieglitz, M.: Lability of DOC transported by Alaskan rivers to the Arctic Ocean, Geophys. Res. Lett., 35, L03402, https://doi.org/10.1029/2007GL032837, 2008.
IPCC: The Physical Science Basis, Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Solomon, S., Qin, D., Manning, M., Chen, Z., Marquis, M., Avery, K. B., Tignor, M., and Miller, H. L., Cambridge University Press, Cambridge, UK and NY, NY, USA, Climate Change, 996 pp., 2007.
Jørgensen, N. O. G., Tranvik, L., Edling, H., Granéli, W., and Lindell, M.: Effects of sunlight on occurrence and bacterial turnover of specific carbon and nitrogen compounds in lake water, FEMS Microbiol. Ecol., 25, 217–227, 1998.
Karlsson, E. S., Charkin, A., Dudarev, O., Semiletov, I., Vonk, J. E., Sánchez-García, L., Andersson, A., and Gustafsson, Ö.: Carbon isotopes and lipid biomarker investigation of sources, transport and degradation of terrestrial organic matter in the Buor-Khaya Bay, SE Laptev Sea, Biogeosciences, 8, 1865–1879, https://doi.org/10.5194/bg-8-1865-2011, 2011.
Kassens, H., Bauch, H. A., Dmitrenko, J. A., Eicken, H., Hubberten, H. W., Melles, M., Thiede, J., and Timokhov, L. A.: Land-Ocean Systems in the Siberian Arctic: Dynamics and History, Springer, Berlin Heidelberg New York, 711 pp., 1999.
Kodina, L. A.: The carbon isotope composition of phytoplankton along the Ob-Kara Sea transect in August-September 1999, Rep. Polar Res., 393, 157–160, 2001.
Kodina, L. A.: Carbon isotope composition of phytoplankton in the Yenisei River-estuary-open sea system and the application of isotopic approach for evaluation of phytoplankton contribution to the Yenisei POC load, Ber. Polarforsch., 419, 143–149, 2002.
Lara, R. J., Rachold, V., Kattner, G., Hubberten, H.-W., Guggenbergen, G., Skoog, A., and Thomas, D. N.: Dissolved organic matter and nutrients in the Lena River, Siberian Arctic: Characteristics and distribution, Mar. Chem., 59, 301–309, 1998.
Lewis, E. and Wallace, D. W. R.: Program developed for CO2 system calculations, ORNL/CDIAC-105, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, Tennessee, 1998.
Macdonald, R. W., Anderson, L. G., Christensen, J. P., Miller, L. A., Semiletov, I. P., and Stein, R.: The Arctic Ocean: Budgets and fluxes, in: Carbon and Nutrient Fluxes in Continental Margins: A Global Synthesis, edited by: Liu, K.-K., Atkinson, L., Quinones, R., and Talaue-McManus, L., Springer, Berlin, 291–303, 2008.
Mantoura, R. F. C. and Woodward, E. M. S.: Conservative behavior of riverine dissolved organic-carbon in the Severn Estuary – chemical and geochemical implications, Geochim. Cosmochim. Ac., 47, 1293–1309, 1983.
McGuire, A. D., Christensen, T. R., Hayes, D., Heroult, A., Euskirchen, E., Kimball, J. S., Koven, C., Lafleur, P., Miller, P. A., Oechel, W., Peylin, P., Williams, M., and Yi, Y.: An assessment of the carbon balance of Arctic tundra: comparisons among observations, process models, and atmospheric inversions, Biogeosciences, 9, 3185–3204, https://doi.org/10.5194/bg-9-3185-2012, 2012.
Mehrbach, C., Culberson, C. H., Hawley, J. E., and Pytkowicz, R. M.: Measurement of the apparent dissociation constants of carbonic acid in seawater at atmospheric pressure, Limnol. Oceanogr., 18, 897–907, 1973.
Nicolsky, D. and Shakhova, N.: Modeling sub-sea permafrost in the East-Siberian Arctic Shelf: the Dmitry Laptev Strait, Env. Res. Lett., 5, https://doi.org/10.1088/1748-9326/5/1/015006, 2010.
Nicolsky, D. J., Romanovsky, V. E., Romanovskii, N. N., Kholodov, A. L., Shakhova, N. E., and Semiletov, I. P.: Modeling sub-sea permafrost in the East Siberian Arctic Shelf: The Laptev Sea region, J. Geophys. Res., 117, F03028, https://doi.org/10.1029/2012JF002358, 2012.
Nikiforov, E. G. and Shpaikher, A. O.: Features of the formation of hydrological regime large-scale variations in the Arctic Ocean, Hydrometeoizdat, Leningrad, 269 pp., 1980 (in Russian).
Pavlova, G. Yu., Tishchenko, P. Ya., Volkova, T. I., Dickson, A., and Wallmann, K.: Intercalibration of Bruevich's method to determine the total alkalinity in seawater, Oceanology, 48, 460–465, 2008.
Petelin, V. P.: New method of water-mechanical analysis of marine bottom sediment, Oceanology, 1, 143–148, 1961 (in Russian).
Pipko, I. I., Semiletov, I. P., and Pugach, S. P.: The carbonate system of the East Siberian Sea waters, Dokl. Earth Sci., 402, 624–627, 2005.
Pipko, I., Semiletov, I. P., Tishchenko, P. Ya., Pugach, S. P., and Savel'eva, N. I.: Variability of the carbonate system parameters in the coast–shelf zone of the East Siberian Sea during the autumn season, Oceanology, 48, 1, 54–67, 2008.
Pipko, I. I., Pugach, S. P., Dudarev, O. V., Charkin, A. N., and Semiletov, I. P.: Carbonate parameters of the Lena River: Characteristics and distribution, Geochem. Int., 48, 1131–1137, 2010.
Pipko, I. I., Semiletov, I. P., Pugach, S. P., Wåhlström, I., and Anderson, L. G.: Interannual variability of air-sea CO2 fluxes and carbon system in the East Siberian Sea, Biogeosciences, 8, 1987–2007, https://doi.org/10.5194/bg-8-1987-2011, 2011a.
Pipko, I. I., Pugach, S. P., Semiletov, I. P., and Salyuk, A. N.: Carbonate Characteristics of Waters of the Arctic Ocean Continental Slope, Dokl. Earth Sci., 438, 858–863, 2011b.
Porcelli, D., Andersson, P., Baskaran, M., Frank, M., Björk, G., and Semiletov, I.: The distribution of neodymium isotopes in Arctic Ocean basins, Geochim. Cosmochim. Ac., 73, 2645–2659, 2009.
Proshutinsky, A. Y. and Johnson, M. A.: Two circulation regimes of the wind-driven Arctic Ocean, J. Geophys. Res., 102, 12493–12514, 1997.
Proshutinsky, A., Timmermans, M.-L., Ashik, I., Beszczynska-Moeller, A., Carmack, E., Frolov, I., Ingvaldsen, R., Itoh, M., Kikuchi, T., Krishfield, R., McLaughlin, F., Loeng, H., Nishino, S., Puickart, R., Rabe, B., Rudels, B., Semiletov, I., Schauer, U., Shakhova, N., Shimada, K., Sokolov, V., Steele, M., Toole, J., Weingarther, T., Williams, W., Woodgate, R., Yamamoto-Kawai, M., and Zimmermann, S.: The Arctic Ocean, in: State of the Climate in 2011, B. Am. Meteorol. Soci., 93, S142–S145, 2012.
Pugach, S. P. and Pipko, I. I.: Dynamic of colored dissolved organic matter on the East-Siberian Sea shelf, Dokl. Earth Sci., 448, 153–156, 2013.
Rachold, V., Grigoriev, M. N., Are, F. E., Solomon, S., Reimnnitz, E., Kassens, H., and Antonow, M.: Coastal erosion vs. riverine sediment discharge in the Arctic shelf seas, Int. J. Earth Sci., 89, 450–460, 2000.
Rachold, V., Eicken, H., Gordeev, V., Grigoriev, M., Hubberten, H., Lisitzin, A., Shevchenko, V., and Schirmeister, L.: Modern terrigenous organic carbon input to the Arctic Ocean, in: edited by: The Organic Carbon Cycle in the Arctic Ocean, Stein, R. and Macdonald, R. W., Springer-Verlag, Berlin, Heidelberg, New York, 512 pp., 2004.
Sánchez-Garcia, L., Alling, V., Pugach, S., Vonk, J., van Dongen, B., Humborg, C., Dudarev, O., Semiletov, I., and Gustafsson, Ö.: Inventories and behavior of particulate organic carbon in the Laptev and East Siberian seas, Global Biogeochem. Cy., 25, GB2007, https://doi.org/10.1029/2010GB003862, 2011.
Savelieva, N. I., Semiletov, I. P., Vasilevskaya, L. N., and Pugach, S. P.: A climate shift in seasonal values of meteorological and hydrological parameters for Northeastern Asia, Prog. Oceanogr., 47, 279–297, 2000.
Semiletov, I. P.: Ancient ice air content of the Vostok Ice Core, in: Biogeochemistry of Trace Gases, edited by: Oremland, S., Chapman and Hall Inc., New York, 46–59, 1993.
Semiletov, I. P.: On aquatic sources and sinks of CO2 and CH4 in the polar regions, J. Atmos. Sci., 56, 286–306, 1999a.
Semiletov, I. P.: The failure of coastal frozen rock as an important factor in the biogeochemistry of the arctic shelf water, Dokl. Earth Sci., 369(8), 1140–1143, 1999b.
Semiletov, I. P. and Pipko, I. I.: Sinks and sources of carbon dioxide in the Arctic Ocean: Results of direct instrumental measurements, Dokl. Earth Sci., 414, 642–645, 2007.
Semiletov, I. P., Pipko, I. I., Pivovarov, N. Ya., Popov, V. V., Zimov, S. A., Voropaev, Yu. V., and Daviodov, S. P.: Atmospheric carbon emission from north Asian lakes: A factor of global significance, Atmos. Environ., 30, 1657–1671, 1996a.
Semiletov, I. P., Pivovarov, N. Ya., Pipko, I. I., Gukov, A.Yu., Volkova, T. I., Sharp, J. P., Shcherbakov, Yu. S., and Fedorov, K. P.: Dynamics of dissolved CH4 and CO2 in the Lena River Delta and Laptev Sea, Transactions (Doklady) of the Russian Academy of Sciences, 350, 401–404, 1996b (translated into English).
Semiletov, I. P., Savelieva, N. I., Weller, G. E., Pipko, I. I., Pugach, S. P., Gukov, A. Yu., and Vasilevskaya, L. N.: The dispersion of Siberian river flows into coastal waters: Meteorological, hydrological and hydrochemical aspects, in: The Freshwater Budget of the Arctic Ocean, NATO Meeting/NATO ASI Series, edited by: Lewis, E. L., Kluwer Academic Publishers, Dordrecht, 323–367, 2000.
Semiletov, I. P., Makshtas, A., Akasofu, S.-I., and Andreas, E.: Atmospheric CO2 balance: The role of Arctic sea ice, Geophys. Res. Lett., 31, L05121, https://doi.org/10.1029/2003GL017996, 2004.
Semiletov, I., Dudarev, O., Luchin, V., Charkin, A., Shin, K., and Tanaka, N.: The East-Siberian Sea as a transition zone between the Pacific origin water and local shelf water, Geophys. Res. Lett., 32, L10614, https://doi.org/10.1029/2005GL022490, 2005.
Semiletov, I. P., Pipko, I. I., Repina, I., and Shakhova, N. E.: Carbonate chemistry dynamics and carbon dioxide fluxes across the atmosphere-ice-water interfaces in the Arctic Ocean: Pacific sector of the Arctic, J. Marine Syst., 66, 204–226, 2007.
Semiletov, I. P., Pipko, I. I., Shakhova, N. E., Dudarev, O. V., Pugach, S. P., Charkin, A. N., McRoy, C. P., Kosmach, D., and Gustafsson, Ö.: Carbon transport by the Lena River from its headwaters to the Arctic Ocean, with emphasis on fluvial input of terrestrial particulate organic carbon vs. carbon transport by coastal erosion, Biogeosciences, 8, 2407–2426, https://doi.org/10.5194/bg-8-2407-2011, 2011.
Semiletov, I. P., Shakhova, N. E., Sergienko, V. I., Pipko, I. I., and Dudarev, O. V.: On carbon transport and fate in the East Siberian Arctic land-shelf-atmosphere system, Environ. Res. Lett., 7, 015201, https://doi.org/10.1088/1748-9326/7/1/015201, 2012.
Shakhova, N. and Semiletov, I.: Methane release and coastal environment in the East Siberian Arctic shelf, J. Mar. Syst., 66 , 227–243, 2007.
Shakhova, N. and Semiletov, I.: Trace gas emissions from sub-sea permafrost. In: Climate Change and the Cryosphere: Snow, Water, Ice and Permafrost in the Arctic (SWIPA): An Arctic Council "Cryosphere Project" in Cooperation with IASC, CliC and IPY, A report of the Arctic Monitoring and Assessment Program (AMAP), Oslo, Norway, 97–104, 2012.
Shakhova, N. E., Nicolsky, D., and Semiletov, I. P.: Current state of subsea permafrost on the East Siberian Shelf: Tests of modeling results based on field observations, Dokl. Earth Sci., 429, 1518–1521, 2009a.
Shakhova, N. E., Sergienko, V. I., and Semiletov, I. P.: Modern state of the role of the East Siberian Shelf in the methane cycle, Her. Russ. Acad. Sci.+, 79, 507–518, 2009b (translated into English by Springer).
Shakhova, N., Semiletov, I., Leifer, I., Rekant, P., Salyuk, A., and Kosmach, D.: Geochemical and geophysical evidence of methane release from the inner East Siberian Shelf, J. Geophys. Res., 115, C08007, https://doi.org/10.1029/2009JC005602, 2010a.
Shakhova, N., Semiletov, I., Salyuk, A., Yusupov, V., Kosmach, D., and Gustafsson, Ö.: Extensive methane venting to the atmosphere from sediments of the East Siberian Arctic Shelf, Science, 327, 1246–1250, 2010b.
Shakhova, N., Semiletov I., and Gustafsson, Ö.: Methane from the East Siberian Arctic Shelf/Response, Science, 329, 1147–1148, 2010c.
Shepard, F. P.: Nomenclature based on sand-silt-clay ratios, J. Sediment. Petrol., 24, 151–158, 1954.
Soloviev, V. A., Ginzburg, G. D., Telepnev, E. B., and Mihalyuk, Yu. N.: Cryothermia and natural gas hydrates within the Arctic Ocean, Sevmorgeologiya, Leningrad, 150 pp., 1987 (in Russian).
Sondergaard, M. and Middelboe, M.: A cross-system analysis of labile dissolved organic carbon, Mar. Ecol.-Prog. Ser., 118, 283–294, 1995.
Sorokin, Yu. A. and Sorokin, P. Yu.: Plankton and primary production in the Lena River estuary and in the South-eastern Laptev Sea, Estuar. Coast. Shelf Sci., 43, 399–418, 1996.
Stein, R. and Macdonald, R. W.: The Organic Carbon Cycle in the Arctic Ocean, Springer-Verlag, Berlin, 417 pp., 2004.
Tarnocai, C., Canadell, J. G., Schuur, E. A. G., Kuhry, P., Mazhitova, G., and Zimov, S.: Soil organic carbon pools in the northern circumpolar permafrost region, Global Biogeochem. Cy., 23, GB2023, https://doi.org/10.1029/2008GB003327, 2009.
van Dongen, B. E., Semiletov, I. P., Weijers, J. W. H., and Gustafsson, Ö.: Contrasting lipid biomarker composition of terrestrial organic matter exported from across the Eurasian Arctic by the five Great Russian Arctic Rivers, Global Biogeochem. Cy., 22, GB1011, https://doi.org/10.1029/2007GB002974, 2008.
Vonk, J. E., Sánchez-García, L., Semiletov, I., Dudarev, O., Eglinton, T., Andersson, A., and Gustafsson, Ö.: Molecular and radiocarbon constraints on sources and degradation of terrestrial organic carbon along the Kolyma paleoriver transect, East Siberian Sea, Biogeosciences, 7, 3153–3166, https://doi.org/10.5194/bg-7-3153-2010, 2010.
Vonk, J. E., Sánchez-García, L., van Dongen, B. E., Alling, V., Kosmach, D., Charkin, A., Semiletov, I. P., Dudarev, O. V., Shakhova, N., Roos, P., Eglinton, T. I., Andersson, A. and Gustafsson, Ö.: Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia, Nature, 489, 137–140, 2012.
Walsh, J. J., McRoy, C. P., Coachman, L. K., Goering, J. J., Nihoul, J. J., Whitledge, T. E., Blackburn, T. H., Parker, P. L., Wirick, C. D., Shuert, P. G., Grebmeier, J. M., Springer, A. M., Tripp, R. D., Hansell, D. A., Djenidi, S., Deleersnijder, E., Henriksen, K., Lund, B. A., Andersen, P., Muller-Karger, F. E., and Dean, K.: Carbon and nitrogen cycling within the Bering/Chukchi Seas: Source regions for organic matter effecting AOU demands of the Arctic Ocean, Prog. Oceanogr., 22, 277–359, 1989.
Wanninkhof, R.: Relationship between wind speed and gas exchange over the ocean, J. Geophys. Res., 97, 7373–7382, 1992.
Wanninkhof, R. and McGillis, W. R.: A cubic relationship between air-sea CO2 exchange and wind speed, Geophys. Res. Lett., 26, 1889–1892, 1999.
Weiss, R. F.: The solubility of nitrogen, oxygen and argon in water and seawater, Deep-Sea Res., 17, 721–735, 1970.
Weiss, R. F.: Determination of gas carbon dioxide and methane by duel catalyst flame ionization chromatography and nitrous oxide by electron capture chromatography, J. Chromatogr. Sci., 19, 611–616, 1981.
Wiegner, T. N. and Seitzinger, S. P.: Photochemical and microbial degradation of external dissolved organic matter inputs to rivers, Aquat. Microb. Ecol., 24, 27–40, 2001.
Zimov, S. A., Semiletov, I. P., Daviodov, S. P., Voropaev, Yu. V., Prosyannikov, S. F., Wong, C. S., and Chan, Y.-H.: Wintertime CO2 emission from soils of Northeastern Siberia, Arctic, 46, 197–204, 1993.
Zimov, S. A., Voropaev, Yu. V., Semiletov, I. P., Daviodov, S. P., Chapin, F. S., and Trumbore, S.: North Siberian lakes: a methane source fueled by Pleistocene carbon, Science, 277, 800–802, 1997.
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