Articles | Volume 20, issue 2
https://doi.org/10.5194/bg-20-365-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-20-365-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
24 Jan 2023
Research article | Highlight paper |
| 24 Jan 2023
| 24 Jan 2023
Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies
Adam Francis
CORRESPONDING AUTHOR
School of Geosciences, University of Edinburgh, Edinburgh, UK
Raja S. Ganeshram
School of Geosciences, University of Edinburgh, Edinburgh, UK
Robyn E. Tuerena
Scottish Association for Marine Science, Oban, UK
Robert G. M. Spencer
Department of Earth, Ocean & Atmospheric Science, Florida State
University, Tallahassee, Florida, USA
Robert M. Holmes
Woodwell Climate Research Center, Falmouth, Massachusetts, USA
Jennifer A. Rogers
Department of Earth, Ocean & Atmospheric Science, Florida State
University, Tallahassee, Florida, USA
Claire Mahaffey
Department of Earth, Ocean and Ecological Sciences, University of
Liverpool, UK
Related authors
No articles found.
Eva L. Doting, Ian T. Stevens, Anne M. Kellerman, Pamela E. Rossel, Runa Antony, Amy M. McKenna, Martyn Tranter, Liane G. Benning, Robert G. M. Spencer, Jon R. Hawkings, and Alexandre M. Anesio
EGUsphere, https://doi.org/10.5194/egusphere-2024-492, https://doi.org/10.5194/egusphere-2024-492, 2024
Short summary
Short summary
This study provides new insights into the transformation of dissolved organic matter (DOM) that takes place as meltwater flows through the porous crust of weathering ice that covers glacier ice surfaces during the melt season. Movement of water through the weathering crust is slow, allowing microorganisms and sunlight to alter the DOM in glacial meltwater. This is important as supraglacial meltwaters deliver DOM and nutrients to microorganisms living in downstream receiving aquatic environments.
Zhibo Shao, Yangchun Xu, Hua Wang, Weicheng Luo, Lice Wang, Yuhong Huang, Nona Sheila R. Agawin, Ayaz Ahmed, Mar Benavides, Mikkel Bentzon-Tilia, Ilana Berman-Frank, Hugo Berthelot, Isabelle C. Biegala, Mariana B. Bif, Antonio Bode, Sophie Bonnet, Deborah A. Bronk, Mark V. Brown, Lisa Campbell, Douglas G. Capone, Edward J. Carpenter, Nicolas Cassar, Bonnie X. Chang, Dreux Chappell, Yuh-ling Lee Chen, Matthew J. Church, Francisco M. Cornejo-Castillo, Amália Maria Sacilotto Detoni, Scott C. Doney, Cecile Dupouy, Marta Estrada, Camila Fernandez, Bieito Fernández-Castro, Debany Fonseca-Batista, Rachel A. Foster, Ken Furuya, Nicole Garcia, Kanji Goto, Jesús Gago, Mary R. Gradoville, M. Robert Hamersley, Britt A. Henke, Cora Hörstmann, Amal Jayakumar, Zhibing Jiang, Shuh-Ji Kao, David M. Karl, Leila R. Kittu, Angela N. Knapp, Sanjeev Kumar, Julie LaRoche, Hongbin Liu, Jiaxing Liu, Caroline Lory, Carolin R. Löscher, Emilio Marañón, Lauren F. Messer, Matthew M. Mills, Wiebke Mohr, Pia H. Moisander, Claire Mahaffey, Robert Moore, Beatriz Mouriño-Carballido, Margaret R. Mulholland, Shin-ichiro Nakaoka, Joseph A. Needoba, Eric J. Raes, Eyal Rahav, Teodoro Ramírez-Cárdenas, Christian Furbo Reeder, Lasse Riemann, Virginie Riou, Julie C. Robidart, Vedula V. S. S. Sarma, Takuya Sato, Himanshu Saxena, Corday Selden, Justin R. Seymour, Dalin Shi, Takuhei Shiozaki, Arvind Singh, Rachel E. Sipler, Jun Sun, Koji Suzuki, Kazutaka Takahashi, Yehui Tan, Weiyi Tang, Jean-Éric Tremblay, Kendra Turk-Kubo, Zuozhu Wen, Angelicque E. White, Samuel T. Wilson, Takashi Yoshida, Jonathan P. Zehr, Run Zhang, Yao Zhang, and Ya-Wei Luo
Earth Syst. Sci. Data, 15, 3673–3709, https://doi.org/10.5194/essd-15-3673-2023, https://doi.org/10.5194/essd-15-3673-2023, 2023
Short summary
Short summary
N2 fixation by marine diazotrophs is an important bioavailable N source to the global ocean. This updated global oceanic diazotroph database increases the number of in situ measurements of N2 fixation rates, diazotrophic cell abundances, and nifH gene copy abundances by 184 %, 86 %, and 809 %, respectively. Using the updated database, the global marine N2 fixation rate is estimated at 223 ± 30 Tg N yr−1, which triplicates that using the original database.
Marta Santos-Garcia, Raja S. Ganeshram, Robyn E. Tuerena, Margot C. F. Debyser, Katrine Husum, Philipp Assmy, and Haakon Hop
Biogeosciences, 19, 5973–6002, https://doi.org/10.5194/bg-19-5973-2022, https://doi.org/10.5194/bg-19-5973-2022, 2022
Short summary
Short summary
Terrestrial sources of nitrate are important contributors to the nutrient pool in the fjords of Kongsfjorden and Rijpfjorden in Svalbard during the summer, and they sustain most of the fjord primary productivity. Ongoing tidewater glacier retreat is postulated to favour light limitation and less dynamic circulation in fjords. This is suggested to encourage the export of nutrients to the middle and outer part of the fjord system, which may enhance primary production within and in offshore areas.
Margot C. F. Debyser, Laetitia Pichevin, Robyn E. Tuerena, Paul A. Dodd, Antonia Doncila, and Raja S. Ganeshram
Biogeosciences, 19, 5499–5520, https://doi.org/10.5194/bg-19-5499-2022, https://doi.org/10.5194/bg-19-5499-2022, 2022
Short summary
Short summary
We focus on the exchange of key nutrients for algae production between the Arctic and Atlantic oceans through the Fram Strait. We show that the export of dissolved silicon here is controlled by the availability of nitrate which is influenced by denitrification on Arctic shelves. We suggest that any future changes in the river inputs of silica and changes in denitrification due to climate change will impact the amount of silicon exported, with impacts on Atlantic algal productivity and ecology.
Charlotte Haugk, Loeka L. Jongejans, Kai Mangelsdorf, Matthias Fuchs, Olga Ogneva, Juri Palmtag, Gesine Mollenhauer, Paul J. Mann, P. Paul Overduin, Guido Grosse, Tina Sanders, Robyn E. Tuerena, Lutz Schirrmeister, Sebastian Wetterich, Alexander Kizyakov, Cornelia Karger, and Jens Strauss
Biogeosciences, 19, 2079–2094, https://doi.org/10.5194/bg-19-2079-2022, https://doi.org/10.5194/bg-19-2079-2022, 2022
Short summary
Short summary
Buried animal and plant remains (carbon) from the last ice age were freeze-locked in permafrost. At an extremely fast eroding permafrost cliff in the Lena Delta (Siberia), we found this formerly frozen carbon well preserved. Our results show that ongoing degradation releases substantial amounts of this carbon, making it available for future carbon emissions. This mobilisation at the studied cliff and also similarly eroding sites bear the potential to affect rivers and oceans negatively.
Maria-Theresia Verwega, Christopher J. Somes, Markus Schartau, Robyn Elizabeth Tuerena, Anne Lorrain, Andreas Oschlies, and Thomas Slawig
Earth Syst. Sci. Data, 13, 4861–4880, https://doi.org/10.5194/essd-13-4861-2021, https://doi.org/10.5194/essd-13-4861-2021, 2021
Short summary
Short summary
This work describes a ready-to-use collection of particulate organic carbon stable isotope ratio data sets. It covers the 1960s–2010s and all main oceans, providing meta-information and gridded data. The best coverage exists in Atlantic, Indian and Southern Ocean surface waters during the 1990s. It indicates no major difference between methods and shows decreasing values towards high latitudes, with the lowest in the Southern Ocean, and a long-term decline in all regions but the Southern Ocean.
Robyn E. Tuerena, Joanne Hopkins, Raja S. Ganeshram, Louisa Norman, Camille de la Vega, Rachel Jeffreys, and Claire Mahaffey
Biogeosciences, 18, 637–653, https://doi.org/10.5194/bg-18-637-2021, https://doi.org/10.5194/bg-18-637-2021, 2021
Short summary
Short summary
The Barents Sea is a rapidly changing shallow sea within the Arctic. Here, nitrate, an essential nutrient, is fully consumed by algae in surface waters during summer months. Nitrate is efficiently regenerated in the Barents Sea, and there is no evidence for nitrogen loss from the sediments by denitrification, which is prevalent on other Arctic shelves. This suggests that nitrogen availability in the Barents Sea is largely determined by the supply of nutrients in water masses from the Atlantic.
Noelle A. Held, Eric A. Webb, Matthew M. McIlvin, David A. Hutchins, Natalie R. Cohen, Dawn M. Moran, Korinna Kunde, Maeve C. Lohan, Claire Mahaffey, E. Malcolm S. Woodward, and Mak A. Saito
Biogeosciences, 17, 2537–2551, https://doi.org/10.5194/bg-17-2537-2020, https://doi.org/10.5194/bg-17-2537-2020, 2020
Short summary
Short summary
Trichodesmium is a globally important marine nitrogen fixer that stimulates primary production in the surface ocean. We surveyed metaproteomes of Trichodesmium populations across the North Atlantic and other oceans, and we found that they experience simultaneous phosphate and iron stress because of the biophysical limits of nutrient uptake. Importantly, nitrogenase was most abundant during co-stress, indicating the potential importance of this phenotype to global nitrogen and carbon cycling.
Robyn E. Tuerena, Raja S. Ganeshram, Matthew P. Humphreys, Thomas J. Browning, Heather Bouman, and Alexander P. Piotrowski
Biogeosciences, 16, 3621–3635, https://doi.org/10.5194/bg-16-3621-2019, https://doi.org/10.5194/bg-16-3621-2019, 2019
Short summary
Short summary
The carbon isotopes in algae can be used to predict food sources and environmental change. We explore how dissolved carbon is taken up by algae in the South Atlantic Ocean and how this affects their carbon isotope signature. We find that cell size controls isotope fractionation. We use our results to investigate how climate change may impact the carbon isotopes in algae. We suggest a shift to smaller algae in this region would decrease the carbon isotope ratio at the base of the food web.
Yinghui Wang, Robert G. M. Spencer, David C. Podgorski, Anne M. Kellerman, Harunur Rashid, Phoebe Zito, Wenjie Xiao, Dandan Wei, Yuanhe Yang, and Yunping Xu
Biogeosciences, 15, 6637–6648, https://doi.org/10.5194/bg-15-6637-2018, https://doi.org/10.5194/bg-15-6637-2018, 2018
Short summary
Short summary
With global warming, thawing of permafrost releases dissolved organic matter (DOM) into streams. By analyzing DOM along an alpine stream on the Qinghai–Tibet Plateau, we found DOM was mainly from the active layer, but with deepening of the active layer, the contribution of the deep permafrost layer increased, causing a change in the chemical composition of DOM. From the head- to downstream, DOM is undergoing rapid degradation, but some components are persistent and can be transported downstream.
Related subject area
Biogeochemistry: Stable Isotopes & Other Tracers
Climatic controls on leaf wax hydrogen isotope ratios in terrestrial and marine sediments along a hyperarid-to-humid gradient
Fractionation of stable carbon isotopes during microbial propionate consumption in anoxic rice paddy soils
Sources and sinks of carbonyl sulfide inferred from tower and mobile atmospheric observations in the Netherlands
Downpour dynamics: outsized impacts of storm events on unprocessed atmospheric nitrate export in an urban watershed
The hidden role of dissolved organic carbon in the biogeochemical cycle of carbon in modern redox-stratified lakes
Biogeochemical processes captured by carbon isotopes in redox-stratified water columns: a comparative study of four modern stratified lakes along an alkalinity gradient
Partitioning of carbon export in the euphotic zone of the oligotrophic South China Sea
Determination of respiration and photosynthesis fractionation factors for atmospheric dioxygen inferred from a vegetation–soil–atmosphere analogue of the terrestrial biosphere in closed chambers
Neodymium budget in the Mediterranean Sea: evaluating the role of atmospheric dusts using a high-resolution dynamical-biogeochemical model
Nitrate isotope investigations reveal future impacts of climate change on nitrogen inputs and cycling in Arctic fjords: Kongsfjorden and Rijpfjorden (Svalbard)
Mineralization of autochthonous particulate organic carbon is a fast channel of organic matter turnover in Germany's largest drinking water reservoir
Carbon isotopic ratios of modern C3 and C4 vegetation on the Indian peninsula and changes along the plant–soil–river continuum – implications for vegetation reconstructions
Controls on nitrite oxidation in the upper Southern Ocean: insights from winter kinetics experiments in the Indian sector
Tracing the source of nitrate in a forested stream showing elevated concentrations during storm events
Intra-skeletal variability in phosphate oxygen isotope composition reveals regional heterothermies in marine vertebrates
Isotopic differences in soil–plant–atmosphere continuum composition and control factors of different vegetation zones on the northern slope of the Qilian Mountains
An analysis of the variability in δ13C in macroalgae from the Gulf of California: indicative of carbon concentration mechanisms and isotope discrimination during carbon assimilation
Summertime productivity and carbon export potential in the Weddell Sea, with a focus on the waters adjacent to Larsen C Ice Shelf
Particulate biogenic barium tracer of mesopelagic carbon remineralization in the Mediterranean Sea (PEACETIME project)
Hydrogen and carbon isotope fractionation factors of aerobic methane oxidation in deep-sea water
Host-influenced geochemical signature in the parasitic foraminifera Hyrrokkin sarcophaga
Comparing modified substrate-induced respiration with selective inhibition (SIRIN) and N2O isotope approaches to estimate fungal contribution to denitrification in three arable soils under anoxic conditions
How are oxygen budgets influenced by dissolved iron and growth of oxygenic phototrophs in an iron-rich spring system? Initial results from the Espan Spring in Fürth, Germany
Stable isotope ratios in seawater nitrate reflect the influence of Pacific water along the northwest Atlantic margin
High-resolution 14C bomb peak dating and climate response analyses of subseasonal stable isotope signals in wood of the African baobab – a case study from Oman
Geographic variability in freshwater methane hydrogen isotope ratios and its implications for global isotopic source signatures
Seasonality of nitrogen sources, cycling, and loading in a New England river discerned from nitrate isotope ratios
Evaluating the response of δ13C in Haloxylon ammodendron, a dominant C4 species in Asian desert ecosystems, to water and nitrogen addition as well as the availability of its δ13C as an indicator of water use efficiency
Modern silicon dynamics of a small high-latitude subarctic lake
Radium-228-derived ocean mixing and trace element inputs in the South Atlantic
Nitrogen isotopic fractionations during nitric oxide production in an agricultural soil
Silicon uptake and isotope fractionation dynamics by crop species
Barium stable isotopes as a fingerprint of biological cycling in the Amazon River basin
Bottomland hardwood forest growth and stress response to hydroclimatic variation: evidence from dendrochronology and tree ring Δ13C values
N2O isotope approaches for source partitioning of N2O production and estimation of N2O reduction – validation with the 15N gas-flux method in laboratory and field studies
Technical note: Single-shell δ11B analysis of Cibicidoides wuellerstorfi using femtosecond laser ablation MC-ICPMS and secondary ion mass spectrometry
Biogeochemical evidence of anaerobic methane oxidation and anaerobic ammonium oxidation in a stratified lake using stable isotopes
Effects of 238U variability and physical transport on water column 234Th downward fluxes in the coastal upwelling system off Peru
Do degree and rate of silicate weathering depend on plant productivity?
Alpine Holocene tree-ring dataset: age-related trends in the stable isotopes of cellulose show species-specific patterns
Ideas and perspectives: The same carbon behaves like different elements – an insight into position-specific isotope distributions
Seasonal dynamics of the COS and CO2 exchange of a managed temperate grassland
Leaf-scale quantification of the effect of photosynthetic gas exchange on Δ17O of atmospheric CO2
The stable carbon isotope signature of methane produced by saprotrophic fungi
Understanding the effects of early degradation on isotopic tracers: implications for sediment source attribution using compound-specific isotope analysis (CSIA)
Oxygen isotope composition of waters recorded in carbonates in strong clumped and oxygen isotopic disequilibrium
Isotopic evidence for alteration of nitrous oxide emissions and producing pathways' contribution under nitrifying conditions
Trace element composition of size-fractionated suspended particulate matter samples from the Qatari Exclusive Economic Zone of the Arabian Gulf: the role of atmospheric dust
Benthic carbon fixation and cycling in diffuse hydrothermal and background sediments in the Bransfield Strait, Antarctica
Changes in gross oxygen production, net oxygen production, and air-water gas exchange during seasonal ice melt in Whycocomagh Bay, a Canadian estuary in the Bras d'Or Lake system
Nestor Gaviria-Lugo, Charlotte Läuchli, Hella Wittmann, Anne Bernhardt, Patrick Frings, Mahyar Mohtadi, Oliver Rach, and Dirk Sachse
Biogeosciences, 20, 4433–4453, https://doi.org/10.5194/bg-20-4433-2023, https://doi.org/10.5194/bg-20-4433-2023, 2023
Short summary
Short summary
We analyzed how leaf wax hydrogen isotopes in continental and marine sediments respond to climate along one of the strongest aridity gradients in the world, from hyperarid to humid, along Chile. We found that under extreme aridity, the relationship between hydrogen isotopes in waxes and climate is non-linear, suggesting that we should be careful when reconstructing past hydrological changes using leaf wax hydrogen isotopes so as to avoid overestimating how much the climate has changed.
Ralf Conrad and Peter Claus
Biogeosciences, 20, 3625–3635, https://doi.org/10.5194/bg-20-3625-2023, https://doi.org/10.5194/bg-20-3625-2023, 2023
Short summary
Short summary
Knowledge of carbon isotope fractionation is important for the assessment of the pathways involved in the degradation of organic matter. Propionate is an important intermediate. In the presence of sulfate, it was degraded by Syntrophobacter species via acetate to CO2. In the absence of sulfate, it was mainly consumed by Smithella and methanogenic archaeal species via butyrate and acetate to CH4. However, stable carbon isotope fractionation during the degradation process was quite small.
Alessandro Zanchetta, Linda M. J. Kooijmans, Steven van Heuven, Andrea Scifo, Hubertus A. Scheeren, Ivan Mammarella, Ute Karstens, Jin Ma, Maarten Krol, and Huilin Chen
Biogeosciences, 20, 3539–3553, https://doi.org/10.5194/bg-20-3539-2023, https://doi.org/10.5194/bg-20-3539-2023, 2023
Short summary
Short summary
Carbonyl sulfide (COS) has been suggested as a tool to estimate carbon dioxide (CO2) uptake by plants during photosynthesis. However, understanding its sources and sinks is critical to preventing biases in this estimate. Combining observations and models, this study proves that regional sources occasionally influence the measurements at the 60 m tall Lutjewad tower (1 m a.s.l.; 53°24′ N, 6°21′ E) in the Netherlands. Moreover, it estimates nighttime COS fluxes to be −3.0 ± 2.6 pmol m−2 s−1.
Joel T. Bostic, David M. Nelson, and Keith N. Eshleman
Biogeosciences, 20, 2485–2498, https://doi.org/10.5194/bg-20-2485-2023, https://doi.org/10.5194/bg-20-2485-2023, 2023
Short summary
Short summary
Land-use changes can affect water quality. We used tracers of pollution sources and water flow paths to show that an urban watershed exports variable sources during storm events relative to a less developed watershed. Our results imply that changing precipitation patterns combined with increasing urbanization may alter sources of pollution in the future.
Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
Biogeosciences, 20, 2405–2424, https://doi.org/10.5194/bg-20-2405-2023, https://doi.org/10.5194/bg-20-2405-2023, 2023
Short summary
Short summary
Dissolved organic carbon (DOC) is a reservoir of prime importance in the C cycle of both continental and marine systems. It has also been suggested to influence the past Earth climate but is still poorly characterized in ancient-Earth-like environments. In this paper we show how DOC analyses from modern redox-stratified lakes can evidence specific metabolic reactions and environmental factors and how these can help us to interpret the C cycle of specific periods in the Earth's past.
Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
Biogeosciences, 20, 2347–2367, https://doi.org/10.5194/bg-20-2347-2023, https://doi.org/10.5194/bg-20-2347-2023, 2023
Short summary
Short summary
We describe the C cycle of four modern stratified water bodies from Mexico, a necessary step to better understand the C cycle of primitive-Earth-like environments, which were dominated by these kinds of conditions. We highlight the importance of local external factors on the C cycle of these systems. Notably, they influence the sensitivity of the carbonate record to environmental changes. We also show the strong C-cycle variability among these lakes and their organic C sediment record.
Yifan Ma, Kuanbo Zhou, Weifang Chen, Junhui Chen, Jin-Yu Terence Yang, and Minhan Dai
Biogeosciences, 20, 2013–2030, https://doi.org/10.5194/bg-20-2013-2023, https://doi.org/10.5194/bg-20-2013-2023, 2023
Short summary
Short summary
We distinguished particulate organic carbon (POC) export fluxes out of the nutrient-depleted layer (NDL) and the euphotic zone. The amount of POC export flux at the NDL base suggests that the NDL could be a hotspot of particle export. The substantial POC export flux at the NDL base challenges traditional concepts that the NDL was limited in terms of POC export. The dominant nutrient source for POC export fluxes should be subsurface nutrients, which was determined by 15N isotopic mass balance.
Clémence Paul, Clément Piel, Joana Sauze, Nicolas Pasquier, Frédéric Prié, Sébastien Devidal, Roxanne Jacob, Arnaud Dapoigny, Olivier Jossoud, Alexandru Milcu, and Amaëlle Landais
Biogeosciences, 20, 1047–1062, https://doi.org/10.5194/bg-20-1047-2023, https://doi.org/10.5194/bg-20-1047-2023, 2023
Short summary
Short summary
To improve the interpretation of the δ18Oatm and Δ17O of O2 in air bubbles in ice cores, we need to better quantify the oxygen fractionation coefficients associated with biological processes. We performed a simplified analogue of the terrestrial biosphere in a closed chamber. We found a respiration fractionation in agreement with the previous estimates at the microorganism scale, and a terrestrial photosynthetic fractionation was found. This has an impact on the estimation of the Dole effect.
Mohamed Ayache, Jean-Claude Dutay, Kazuyo Tachikawa, Thomas Arsouze, and Catherine Jeandel
Biogeosciences, 20, 205–227, https://doi.org/10.5194/bg-20-205-2023, https://doi.org/10.5194/bg-20-205-2023, 2023
Short summary
Short summary
The neodymium (Nd) is one of the most useful tracers to fingerprint water mass provenance. However, the use of Nd is hampered by the lack of adequate quantification of the external sources. Here, we present the first simulation of dissolved Nd concentration and Nd isotopic composition in the Mediterranean Sea using a high-resolution model. We aim to better understand how the various external sources affect the Nd cycle and particularly assess how it is impacted by atmospheric inputs.
Marta Santos-Garcia, Raja S. Ganeshram, Robyn E. Tuerena, Margot C. F. Debyser, Katrine Husum, Philipp Assmy, and Haakon Hop
Biogeosciences, 19, 5973–6002, https://doi.org/10.5194/bg-19-5973-2022, https://doi.org/10.5194/bg-19-5973-2022, 2022
Short summary
Short summary
Terrestrial sources of nitrate are important contributors to the nutrient pool in the fjords of Kongsfjorden and Rijpfjorden in Svalbard during the summer, and they sustain most of the fjord primary productivity. Ongoing tidewater glacier retreat is postulated to favour light limitation and less dynamic circulation in fjords. This is suggested to encourage the export of nutrients to the middle and outer part of the fjord system, which may enhance primary production within and in offshore areas.
Marlene Dordoni, Michael Seewald, Karsten Rinke, Kurt Friese, Robert van Geldern, Jakob Schmidmeier, and Johannes A. C. Barth
Biogeosciences, 19, 5343–5355, https://doi.org/10.5194/bg-19-5343-2022, https://doi.org/10.5194/bg-19-5343-2022, 2022
Short summary
Short summary
Organic matter (OM) turnover into dissolved inorganic carbon (DIC) was investigated by means of carbon isotope mass balances in Germany's largest water reservoir. This includes a metalimnetic oxygen minimum (MOM). Autochthonous particulate organic carbon (POC) was the main contributor to DIC, with rates that were highest for the MOM. Generally low turnover rates outline the environmental fragility of this water body in the case that OM loads increase due to storm events or land use changes.
Frédérique M. S. A. Kirkels, Hugo J. de Boer, Paulina Concha Hernández, Chris R. T. Martes, Marcel T. J. van der Meer, Sayak Basu, Muhammed O. Usman, and Francien Peterse
Biogeosciences, 19, 4107–4127, https://doi.org/10.5194/bg-19-4107-2022, https://doi.org/10.5194/bg-19-4107-2022, 2022
Short summary
Short summary
The distinct carbon isotopic values of C3 and C4 plants are widely used to reconstruct past hydroclimate, where more C3 plants reflect wetter and C4 plants drier conditions. Here we examine the impact of regional hydroclimatic conditions on plant isotopic values in the Godavari River basin, India. We find that it is crucial to identify regional plant isotopic values and consider drought stress, which introduces a bias in C3 / C4 plant estimates and associated hydroclimate reconstructions.
Mhlangabezi Mdutyana, Tanya Marshall, Xin Sun, Jessica M. Burger, Sandy J. Thomalla, Bess B. Ward, and Sarah E. Fawcett
Biogeosciences, 19, 3425–3444, https://doi.org/10.5194/bg-19-3425-2022, https://doi.org/10.5194/bg-19-3425-2022, 2022
Short summary
Short summary
Nitrite-oxidizing bacteria in the winter Southern Ocean show a high affinity for nitrite but require a minimum (i.e., "threshold") concentration before they increase their rates of nitrite oxidation significantly. The classic Michaelis–Menten model thus cannot be used to derive the kinetic parameters, so a modified equation was employed that also yields the threshold nitrite concentration. Dissolved iron availability may play an important role in limiting nitrite oxidation.
Weitian Ding, Urumu Tsunogai, Fumiko Nakagawa, Takashi Sambuichi, Hiroyuki Sase, Masayuki Morohashi, and Hiroki Yotsuyanagi
Biogeosciences, 19, 3247–3261, https://doi.org/10.5194/bg-19-3247-2022, https://doi.org/10.5194/bg-19-3247-2022, 2022
Short summary
Short summary
Excessive leaching of nitrate from forested catchments during storm events degrades water quality and causes eutrophication in downstream areas. Thus, tracing the source of nitrate increase during storm events in forested streams is important for sustainable forest management. Based on the isotopic compositions of stream nitrate, including Δ17O, this study clarifies that the source of stream nitrate increase during storm events was soil nitrate in the riparian zone.
Nicolas Séon, Romain Amiot, Guillaume Suan, Christophe Lécuyer, François Fourel, Fabien Demaret, Arnauld Vinçon-Laugier, Sylvain Charbonnier, and Peggy Vincent
Biogeosciences, 19, 2671–2681, https://doi.org/10.5194/bg-19-2671-2022, https://doi.org/10.5194/bg-19-2671-2022, 2022
Short summary
Short summary
We analysed the oxygen isotope composition of bones and teeth of four marine species possessing regional heterothermies. We observed a consistent link between oxygen isotope composition and temperature heterogeneities recorded by classical methods. This opens up new perspectives on the determination of the thermoregulatory strategies of extant marine vertebrates where conventional methods are difficult to apply, but also allows us to investigate thermophysiologies of extinct vertebrates.
Yuwei Liu, Guofeng Zhu, Zhuanxia Zhang, Zhigang Sun, Leilei Yong, Liyuan Sang, Lei Wang, and Kailiang Zhao
Biogeosciences, 19, 877–889, https://doi.org/10.5194/bg-19-877-2022, https://doi.org/10.5194/bg-19-877-2022, 2022
Short summary
Short summary
We took the water cycle process of soil–plant–atmospheric precipitation as the research objective. In the water cycle of soil–plant–atmospheric precipitation, precipitation plays the main controlling role. The main source of replenishment for alpine meadow plants is precipitation and alpine meltwater; the main source of replenishment for forest plants is soil water; and the plants in the arid foothills mainly use groundwater.
Roberto Velázquez-Ochoa, María Julia Ochoa-Izaguirre, and Martín Federico Soto-Jiménez
Biogeosciences, 19, 1–27, https://doi.org/10.5194/bg-19-1-2022, https://doi.org/10.5194/bg-19-1-2022, 2022
Short summary
Short summary
Our research is the first approximation to understand the δ13C macroalgal variability in one of the most diverse marine ecosystems in the world, the Gulf of California. The life-form is the principal cause of δ13C macroalgal variability, mainly taxonomy. However, changes in habitat characteristics and environmental conditions also influence the δ13C macroalgal variability. The δ13C macroalgae is indicative of carbon concentration mechanisms and isotope discrimination during carbon assimilation.
Raquel F. Flynn, Thomas G. Bornman, Jessica M. Burger, Shantelle Smith, Kurt A. M. Spence, and Sarah E. Fawcett
Biogeosciences, 18, 6031–6059, https://doi.org/10.5194/bg-18-6031-2021, https://doi.org/10.5194/bg-18-6031-2021, 2021
Short summary
Short summary
Biological activity in the shallow Weddell Sea affects the biogeochemistry of recently formed deep waters. To investigate the drivers of carbon and nutrient export, we measured rates of primary production and nitrogen uptake, characterized the phytoplankton community, and estimated nutrient depletion ratios across the under-sampled western Weddell Sea in mid-summer. Carbon export was highest at the ice shelves and was determined by a combination of physical, chemical, and biological factors.
Stéphanie H. M. Jacquet, Christian Tamburini, Marc Garel, Aurélie Dufour, France Van Vambeke, Frédéric A. C. Le Moigne, Nagib Bhairy, and Sophie Guasco
Biogeosciences, 18, 5891–5902, https://doi.org/10.5194/bg-18-5891-2021, https://doi.org/10.5194/bg-18-5891-2021, 2021
Short summary
Short summary
We compared carbon remineralization rates (MRs) in the western and central Mediterranean Sea in late spring during the PEACETIME cruise, as assessed using the barium tracer. We reported higher and deeper (up to 1000 m depth) MRs in the western basin, potentially sustained by an additional particle export event driven by deep convection. The central basin is the site of a mosaic of blooming and non-blooming water masses and showed lower MRs that were restricted to the upper mesopelagic layer.
Shinsuke Kawagucci, Yohei Matsui, Akiko Makabe, Tatsuhiro Fukuba, Yuji Onishi, Takuro Nunoura, and Taichi Yokokawa
Biogeosciences, 18, 5351–5362, https://doi.org/10.5194/bg-18-5351-2021, https://doi.org/10.5194/bg-18-5351-2021, 2021
Short summary
Short summary
Hydrogen and carbon isotope ratios of methane as well as the relevant biogeochemical parameters and microbial community compositions in hydrothermal plumes in the Okinawa Trough were observed. We succeeded in simultaneously determining hydrogen and carbon isotope fractionation factors associated with aerobic oxidation of methane in seawater (εH = 49.4 ± 5.0 ‰, εC = 5.2 ± 0.4 ‰) – the former being the first of its kind ever reported.
Nicolai Schleinkofer, David Evans, Max Wisshak, Janina Vanessa Büscher, Jens Fiebig, André Freiwald, Sven Härter, Horst R. Marschall, Silke Voigt, and Jacek Raddatz
Biogeosciences, 18, 4733–4753, https://doi.org/10.5194/bg-18-4733-2021, https://doi.org/10.5194/bg-18-4733-2021, 2021
Short summary
Short summary
We have measured the chemical composition of the carbonate shells of the parasitic foraminifera Hyrrokkin sarcophaga in order to test if it is influenced by the host organism (bivalve or coral). We find that both the chemical and isotopic composition is influenced by the host organism. For example strontium is enriched in foraminifera that grew on corals, whose skeleton is built from aragonite, which is naturally enriched in strontium compared to the bivalves' calcite shell.
Lena Rohe, Traute-Heidi Anderson, Heinz Flessa, Anette Goeske, Dominika Lewicka-Szczebak, Nicole Wrage-Mönnig, and Reinhard Well
Biogeosciences, 18, 4629–4650, https://doi.org/10.5194/bg-18-4629-2021, https://doi.org/10.5194/bg-18-4629-2021, 2021
Short summary
Short summary
This is the first experimental setup combining a complex set of methods (microbial inhibitors and isotopic approaches) to differentiate between N2O produced by fungi or bacteria during denitrification in three soils. Quantifying the fungal fraction with inhibitors was not successful due to large amounts of uninhibited N2O production. All successful methods suggested a small or missing fungal contribution. Artefacts occurring with microbial inhibition to determine N2O fluxes are discussed.
Inga Köhler, Raul E. Martinez, David Piatka, Achim J. Herrmann, Arianna Gallo, Michelle M. Gehringer, and Johannes A. C. Barth
Biogeosciences, 18, 4535–4548, https://doi.org/10.5194/bg-18-4535-2021, https://doi.org/10.5194/bg-18-4535-2021, 2021
Short summary
Short summary
We investigated how high Fe(II) levels influence the O2 budget of a circum-neutral Fe(II)-rich spring and if a combined study of dissolved O (DO) and its isotopic composition can help assess this effect. We showed that dissolved Fe(II) can exert strong effects on the δ18ODO even though a constant supply of atmospheric O2 occurs. In the presence of photosynthesis, direct effects of Fe oxidation become masked. Critical Fe(II) concentrations indirectly control the DO by enhancing photosynthesis.
Owen A. Sherwood, Samuel H. Davin, Nadine Lehmann, Carolyn Buchwald, Evan N. Edinger, Moritz F. Lehmann, and Markus Kienast
Biogeosciences, 18, 4491–4510, https://doi.org/10.5194/bg-18-4491-2021, https://doi.org/10.5194/bg-18-4491-2021, 2021
Short summary
Short summary
Pacific water flowing eastward through the Canadian Arctic plays an important role in redistributing nutrients to the northwest Atlantic Ocean. Using samples collected from northern Baffin Bay to the southern Labrador Shelf, we show that stable isotopic ratios in seawater nitrate reflect the fraction of Pacific to Atlantic water. These results provide a new framework for interpreting patterns of nitrogen isotopic variability recorded in modern and archival organic materials in the region.
Franziska Slotta, Lukas Wacker, Frank Riedel, Karl-Uwe Heußner, Kai Hartmann, and Gerhard Helle
Biogeosciences, 18, 3539–3564, https://doi.org/10.5194/bg-18-3539-2021, https://doi.org/10.5194/bg-18-3539-2021, 2021
Short summary
Short summary
The African baobab is a challenging climate and environmental archive for its semi-arid habitat due to dating uncertainties and parenchyma-rich wood anatomy. Annually resolved F14C data of tree-ring cellulose (1941–2005) from a tree in Oman show the annual character of the baobab’s growth rings but were up to 8.8 % lower than expected for 1964–1967. Subseasonal δ13C and δ18O patterns reveal years with low average monsoon rain as well as heavy rainfall events from pre-monsoonal cyclones.
Peter M. J. Douglas, Emerald Stratigopoulos, Sanga Park, and Dawson Phan
Biogeosciences, 18, 3505–3527, https://doi.org/10.5194/bg-18-3505-2021, https://doi.org/10.5194/bg-18-3505-2021, 2021
Short summary
Short summary
Hydrogen isotopes could be a useful tool to help resolve the geographic distribution of methane emissions from freshwater environments. We analyzed an expanded global dataset of freshwater methane hydrogen isotope ratios and found significant geographic variation linked to water isotopic composition. This geographic variability could be used to resolve changing methane fluxes from freshwater environments and provide more accurate estimates of the relative balance of global methane sources.
Veronica R. Rollinson, Julie Granger, Sydney C. Clark, Mackenzie L. Blanusa, Claudia P. Koerting, Jamie M. P. Vaudrey, Lija A. Treibergs, Holly C. Westbrook, Catherine M. Matassa, Meredith G. Hastings, and Craig R. Tobias
Biogeosciences, 18, 3421–3444, https://doi.org/10.5194/bg-18-3421-2021, https://doi.org/10.5194/bg-18-3421-2021, 2021
Short summary
Short summary
We measured nutrients and the naturally occurring nitrogen (N) and oxygen (O) stable isotope ratios of nitrate discharged from a New England river over an annual cycle, to monitor N loading and identify dominant sources from the watershed. We uncovered a seasonality to loading and sources of N from the watershed. Seasonality in the nitrate isotope ratios also informed on N cycling, conforming to theoretical expectations of riverine nutrient cycling.
Zixun Chen, Xuejun Liu, Xiaoqing Cui, Yaowen Han, Guoan Wang, and Jiazhu Li
Biogeosciences, 18, 2859–2870, https://doi.org/10.5194/bg-18-2859-2021, https://doi.org/10.5194/bg-18-2859-2021, 2021
Short summary
Short summary
δ13C in plants is a sensitive long-term indicator of physiological acclimatization. The present study suggests that precipitation change and increasing atmospheric N deposition have little impact on δ13C of H. ammodendron, a dominant plant in central Asian deserts, but affect its gas exchange. In addition, this study shows that δ13C of H. ammodendron could not indicate its water use efficiency (WUE), suggesting that whether δ13C of C4 plants indicates WUE is species-specific.
Petra Zahajská, Carolina Olid, Johanna Stadmark, Sherilyn C. Fritz, Sophie Opfergelt, and Daniel J. Conley
Biogeosciences, 18, 2325–2345, https://doi.org/10.5194/bg-18-2325-2021, https://doi.org/10.5194/bg-18-2325-2021, 2021
Short summary
Short summary
The drivers of high accumulation of single-cell siliceous algae (diatoms) in a high-latitude lake have not been fully characterized before. We studied silicon cycling of the lake through water, radon, silicon, and stable silicon isotope balances. Results showed that groundwater brings 3 times more water and dissolved silica than the stream inlet. We demonstrate that groundwater discharge and low sediment deposition have driven the high diatom accumulation in the studied lake in the past century.
Yu-Te Hsieh, Walter Geibert, E. Malcolm S. Woodward, Neil J. Wyatt, Maeve C. Lohan, Eric P. Achterberg, and Gideon M. Henderson
Biogeosciences, 18, 1645–1671, https://doi.org/10.5194/bg-18-1645-2021, https://doi.org/10.5194/bg-18-1645-2021, 2021
Short summary
Short summary
The South Atlantic near 40° S is one of the high-productivity and most dynamic nutrient regions in the oceans, but the sources and fluxes of trace elements (TEs) to this region remain unclear. This study investigates seawater Ra-228 and provides important constraints on ocean mixing and dissolved TE fluxes to this region. Vertical mixing is a more important source than aeolian or shelf inputs in this region, but particulate or winter deep-mixing inputs may be required to balance the TE budgets.
Zhongjie Yu and Emily M. Elliott
Biogeosciences, 18, 805–829, https://doi.org/10.5194/bg-18-805-2021, https://doi.org/10.5194/bg-18-805-2021, 2021
Short summary
Short summary
In this study, we demonstrated distinct nitrogen isotope effects for nitric oxide (NO) production from major microbial and chemical NO sources in an agricultural soil. These results highlight characteristic bond-forming and breaking mechanisms associated with microbial and chemical NO production and implicate that simultaneous isotopic analyses of NO and nitrous oxide (N2O) can lead to unprecedented insights into the sources and processes controlling NO and N2O emissions from agricultural soils.
Daniel A. Frick, Rainer Remus, Michael Sommer, Jürgen Augustin, Danuta Kaczorek, and Friedhelm von Blanckenburg
Biogeosciences, 17, 6475–6490, https://doi.org/10.5194/bg-17-6475-2020, https://doi.org/10.5194/bg-17-6475-2020, 2020
Short summary
Short summary
Silicon is taken up by some plants to increase structural stability and to develop stress resistance and is rejected by others. To explore the underlying mechanisms, we used the stable isotopes of silicon that shift in their relative abundance depending on the biochemical transformation involved. On species with a rejective (tomato, mustard) and active (wheat) uptake mechanism, grown in hydroculture, we found that the transport of silicic acid is controlled by the precipitation of biogenic opal.
Quentin Charbonnier, Julien Bouchez, Jérôme Gaillardet, and Éric Gayer
Biogeosciences, 17, 5989–6015, https://doi.org/10.5194/bg-17-5989-2020, https://doi.org/10.5194/bg-17-5989-2020, 2020
Short summary
Short summary
The abundance and isotope composition of the trace metal barium (Ba) allows us to track and quantify nutrient cycling throughout the Amazon Basin. In particular, we show that the Ba biological fingerprint evolves from that of a strong net nutrient uptake in the mountainous area of the Andes towards efficient nutrient recycling on the plains of the Lower Amazon. Our study highlights the fact that the geochemical signature of rock-derived nutrients transported by the Amazon is scarred by life.
Ajinkya G. Deshpande, Thomas W. Boutton, Ayumi Hyodo, Charles W. Lafon, and Georgianne W. Moore
Biogeosciences, 17, 5639–5653, https://doi.org/10.5194/bg-17-5639-2020, https://doi.org/10.5194/bg-17-5639-2020, 2020
Short summary
Short summary
Wetland forests in the southern USA are threatened by changing climate and human-induced pressures. We used tree ring widths and C isotopes as indicators of forest growth and physiological stress, respectively, and compared these to past climate data. We observed that vegetation growing in the drier patches is susceptible to stress, while vegetation growth and physiology in wetter patches is less sensitive to unfavorable environmental conditions, highlighting the importance of optimal wetness.
Dominika Lewicka-Szczebak, Maciej Piotr Lewicki, and Reinhard Well
Biogeosciences, 17, 5513–5537, https://doi.org/10.5194/bg-17-5513-2020, https://doi.org/10.5194/bg-17-5513-2020, 2020
Short summary
Short summary
We present the first validation of N2O isotopic approaches for estimating N2O source pathways and N2O reduction. These approaches are widely used for tracing soil nitrogen cycling, but the results of these estimations are very uncertain. Here we report the results from parallel treatments allowing for precise validation of these approaches, and we propose the best strategies for results interpretation, including the new idea of an isotope model integrating three isotopic signatures of N2O.
Markus Raitzsch, Claire Rollion-Bard, Ingo Horn, Grit Steinhoefel, Albert Benthien, Klaus-Uwe Richter, Matthieu Buisson, Pascale Louvat, and Jelle Bijma
Biogeosciences, 17, 5365–5375, https://doi.org/10.5194/bg-17-5365-2020, https://doi.org/10.5194/bg-17-5365-2020, 2020
Short summary
Short summary
The isotopic composition of boron in carbonate shells of marine unicellular organisms is a popular tool to estimate seawater pH. Usually, many shells need to be dissolved and measured for boron isotopes, but the information on their spatial distribution is lost. Here, we investigate two techniques that allow for measuring boron isotopes within single shells and show that they yield robust mean values but provide additional information on the heterogeneity within and between single shells.
Florian Einsiedl, Anja Wunderlich, Mathieu Sebilo, Ömer K. Coskun, William D. Orsi, and Bernhard Mayer
Biogeosciences, 17, 5149–5161, https://doi.org/10.5194/bg-17-5149-2020, https://doi.org/10.5194/bg-17-5149-2020, 2020
Short summary
Short summary
Nitrate pollution of freshwaters and methane emissions into the atmosphere are crucial factors in deteriorating the quality of drinking water and in contributing to global climate change. Here, we report vertical concentration and stable isotope profiles of CH4, NO3-, NO2-, and NH4+ in the water column of Fohnsee (southern Bavaria, Germany) that may indicate linkages between nitrate-dependent anaerobic methane oxidation and the anaerobic oxidation of ammonium.
Ruifang C. Xie, Frédéric A. C. Le Moigne, Insa Rapp, Jan Lüdke, Beat Gasser, Marcus Dengler, Volker Liebetrau, and Eric P. Achterberg
Biogeosciences, 17, 4919–4936, https://doi.org/10.5194/bg-17-4919-2020, https://doi.org/10.5194/bg-17-4919-2020, 2020
Short summary
Short summary
Thorium-234 (234Th) is widely used to study carbon fluxes from the surface ocean to depth. But few studies stress the relevance of oceanic advection and diffusion on the downward 234Th fluxes in nearshore environments. Our study in offshore Peru showed strong temporal variations in both the importance of physical processes on 234Th flux estimates and the oceanic residence time of 234Th, whereas salinity-derived seawater 238U activities accounted for up to 40 % errors in 234Th flux estimates.
Ralf A. Oeser and Friedhelm von Blanckenburg
Biogeosciences, 17, 4883–4917, https://doi.org/10.5194/bg-17-4883-2020, https://doi.org/10.5194/bg-17-4883-2020, 2020
Short summary
Short summary
We present a novel strategy to decipher the relative impact of biogenic and abiotic drivers of weathering. We parameterized the nutrient fluxes in four ecosystems along a climate and vegetation gradient situated on the Chilean Coastal Cordillera. We investigated how nutrient demand by plants drives weathering. We found that the increase in biomass nutrient demand is accommodated by faster nutrient recycling rather than an increase in the weathering–release rates.
Tito Arosio, Malin M. Ziehmer, Kurt Nicolussi, Christian Schlüchter, and Markus Leuenberger
Biogeosciences, 17, 4871–4882, https://doi.org/10.5194/bg-17-4871-2020, https://doi.org/10.5194/bg-17-4871-2020, 2020
Short summary
Short summary
Stable isotopes in tree-ring cellulose are tools for climatic reconstructions, but interpretation is challenging due to nonclimate trends. We analyzed the tree-age trends in tree-ring isotopes of deciduous larch and evergreen cembran pine. Samples covering the whole Holocene were collected at the tree line in the Alps. For cambial ages over 100 years, we prove the absence of age trends in δD, δ18O, and δ13C for both species. For lower cambial ages, trends differ for each isotope and species.
Yuyang He, Xiaobin Cao, and Huiming Bao
Biogeosciences, 17, 4785–4795, https://doi.org/10.5194/bg-17-4785-2020, https://doi.org/10.5194/bg-17-4785-2020, 2020
Short summary
Short summary
Different carbon sites in a large organic molecule have different isotope compositions. Different carbon sites may not have the chance to exchange isotopes at all. The lack of appreciation of this notion might be blamed for an unsettled debate on the thermodynamic state of an organism. Here we demonstrate using minerals, N2O, and acetic acid that the dearth of exchange among different carbon sites renders them as independent as if they were different elements in organic molecules.
Felix M. Spielmann, Albin Hammerle, Florian Kitz, Katharina Gerdel, and Georg Wohlfahrt
Biogeosciences, 17, 4281–4295, https://doi.org/10.5194/bg-17-4281-2020, https://doi.org/10.5194/bg-17-4281-2020, 2020
Short summary
Short summary
Carbonyl sulfide (COS) can be used as a proxy for plant photosynthesis on an ecosystem scale. However, the relationships between COS and CO2 fluxes and their dependence on daily to seasonal changes in environmental drivers are still poorly understood. We examined COS and CO2 ecosystem fluxes above an agriculturally used mountain grassland for 6 months. Harvesting of the grassland disturbed the otherwise stable COS-to-CO2 uptake ratio. We even found the canopy to release COS during those times.
Getachew Agmuas Adnew, Thijs L. Pons, Gerbrand Koren, Wouter Peters, and Thomas Röckmann
Biogeosciences, 17, 3903–3922, https://doi.org/10.5194/bg-17-3903-2020, https://doi.org/10.5194/bg-17-3903-2020, 2020
Short summary
Short summary
We measured the effect of photosynthesis, the largest flux in the carbon cycle, on the triple oxygen isotope composition of atmospheric CO2 at the leaf level during gas exchange using three plant species. The main factors that limit the impact of land vegetation on the triple oxygen isotope composition of atmospheric CO2 are identified, characterized and discussed. The effect of photosynthesis on the isotopic composition of CO2 is commonly quantified as discrimination (ΔA).
Moritz Schroll, Frank Keppler, Markus Greule, Christian Eckhardt, Holger Zorn, and Katharina Lenhart
Biogeosciences, 17, 3891–3901, https://doi.org/10.5194/bg-17-3891-2020, https://doi.org/10.5194/bg-17-3891-2020, 2020
Short summary
Short summary
Fungi have recently been identified to produce the greenhouse gas methane. Here, we investigated the stable carbon isotope values of methane produced by saprotrophic fungi. Our results show that stable isotope values of methane from fungi are dependent on the fungal species and the metabolized substrate. They cover a broad range and overlap with stable carbon isotope values of methane reported for methanogenic archaea, the thermogenic degradation of organic matter, and other eukaryotes.
Pranav Hirave, Guido L. B. Wiesenberg, Axel Birkholz, and Christine Alewell
Biogeosciences, 17, 2169–2180, https://doi.org/10.5194/bg-17-2169-2020, https://doi.org/10.5194/bg-17-2169-2020, 2020
Short summary
Short summary
Sediment input into water bodies is a prominent threat to freshwater ecosystems. We tested the stability of tracers employed in freshwater sediment tracing based on compound-specific isotope analysis during early degradation in soil. While bulk δ13C values showed no stability, δ13C values of plant-derived fatty acids and n-alkanes were stably transferred to the soil without soil particle size dependency after an early degradation in organic horizons, thus indicating their suitability as tracers.
Caroline Thaler, Amandine Katz, Magali Bonifacie, Bénédicte Ménez, and Magali Ader
Biogeosciences, 17, 1731–1744, https://doi.org/10.5194/bg-17-1731-2020, https://doi.org/10.5194/bg-17-1731-2020, 2020
Short summary
Short summary
Paleoenvironment reconstructions, retrieved from δ18O and Δ47 values measured in carbonate, are compromised when crystallization occurs in isotopic disequilibrium. We show that some paleoenvironmental information can still be retrieved from these paired disequilibrium Δ47 and δ18O values. The possibility of retrieving information on paleowaters, sediments' interstitial waters, or organisms' body water at the carbonate precipitation loci will help understand past Earth and life evolution.
Guillaume Humbert, Mathieu Sébilo, Justine Fiat, Longqi Lang, Ahlem Filali, Véronique Vaury, Mathieu Spérandio, and Anniet M. Laverman
Biogeosciences, 17, 979–993, https://doi.org/10.5194/bg-17-979-2020, https://doi.org/10.5194/bg-17-979-2020, 2020
Short summary
Short summary
Mitigating emissions of the greenhouse gas N2O requires understanding of the relative contribution of its producing processes in response to environmental variables. We show, using isotopic analysis, that N2O emissions from a nitrifying system were sensitive to oxygenation, temperature and NH4+ concentrations with nitrite reduction being the main N2O source. Temperature appears to be the main control on N2O production, due to its dissimilar effects on ammonium and nitrite oxidizing activities.
Oguz Yigiterhan, Ebrahim Mohd Al-Ansari, Alex Nelson, Mohamed Alaa Abdel-Moati, Jesse Turner, Hamood Abdulla Alsaadi, Barbara Paul, Ibrahim Abdullatif Al-Maslamani, Mehsin Abdulla Al-Ansi Al-Yafei, and James W. Murray
Biogeosciences, 17, 381–404, https://doi.org/10.5194/bg-17-381-2020, https://doi.org/10.5194/bg-17-381-2020, 2020
Short summary
Short summary
We analyze net-tow samples of plankton and associated particulate matter from the Exclusive Economic Zone, Qatar, Arabian Gulf, using net tows with mesh sizes of 50 and 200 μm to examine the composition of plankton populations. We also focus on the role and composition of the atmospheric dust, representative of terrigenous material, deposited in the Gulf. We concluded that Al, Fe, Cr, Co, Mn, Ni, Pb, and Li are of dust origin and As, Cd, Cu, Mo, Zn, and Ca are of anthropogenic/biogenic origin.
Clare Woulds, James B. Bell, Adrian G. Glover, Steven Bouillon, and Louise S. Brown
Biogeosciences, 17, 1–12, https://doi.org/10.5194/bg-17-1-2020, https://doi.org/10.5194/bg-17-1-2020, 2020
Short summary
Short summary
Sedimented hydrothermal vents occur where heated, mineral-rich (hydrothermal) water seeps through seafloor sediments. They host chemosynthetic microbes, which use chemical energy to fix dissolved carbon dioxide into sugars (chemosynthesis). We conducted carbon tracing experiments, and observed chemosynthesis at both vent and non-vent sites. Thus, chemosynthesis occurred over a much larger area than expected, suggesting it is more widespread than previously thought.
Cara C. Manning, Rachel H. R. Stanley, David P. Nicholson, Brice Loose, Ann Lovely, Peter Schlosser, and Bruce G. Hatcher
Biogeosciences, 16, 3351–3376, https://doi.org/10.5194/bg-16-3351-2019, https://doi.org/10.5194/bg-16-3351-2019, 2019
Short summary
Short summary
We measured rates of biological activity and gas exchange in a Canadian estuary during ice melt. We quantified gas exchange using inert, deliberately released tracers and found that the gas transfer rate at > 90 % ice cover was 6 % of the rate for nearly ice-free conditions. We measured oxygen concentration and isotopic composition and used the data to detect changes in the rates of photosynthesis and respiration (autotrophy and heterotrophy) as the ice melted.
Cited articles
Amon, R. M. W., Rinehart, A. J., Duan, S., Louchouarn, P., Prokushkin, A.,
Guggenberger, G., Bauch, D., Stedmon, C., Raymond, P. A., Holmes, R. M.,
McClelland, J. W., Peterson, B. J., Walker, S. A., and Zhulidov, A. V.:
Dissolved organic matter sources in large Arctic rivers, Geochim. Cosmochim. Ac., 94, 217–237, https://doi.org/10.1016/J.GCA.2012.07.015, 2012.
Anisimov, O. and Reneva, S.: Permafrost and changing climate: the Russian
perspective, Ambio, 35, 169–175, https://doi.org/10.1579/0044-7447(2006)35[169:pacctr]2.0.co;2, .
Beermann, F., Langer, M., Wetterich, S., Strauss, J., Boike, J., Fiencke,
C., Schirrmeister, L., Pfeiffer, E.-M., and Kutzback, L.: Permafrost thaw
and liberation of inorganic nitrogen in Eastern Siberia, Permafrost Perigl., 28, 605–618, https://doi.org/10.1002/ppp.1958, 2017.
Berhe, A. A., Harte, J., Harden, J. W., and Torn, M. S.: The Significance of the
Erosion-induced Terrestrial Carbon Sink, BioScience, Narnia, 57, 337–346, https://doi.org/10.1641/B570408, 2007.
Botrel, M., Bristow, L. A., Altabet, M. A., Gregory-Eaves, I., and Maranger, R.:
Assimilation and nitrification in pelagic waters: insights using dual
nitrate stable isotopes (δ15N, δ18O) in a shallow lake,
Biogeochemistry, Springer International Publishing, 135, 221–237,
https://doi.org/10.1007/s10533-017-0369-y, 2017.
Brabets, T., Wang, B., and Meade, R.: Environmental and Hydrologic Overview
of the Yukon River Basin, Alaska and Canada Water-Resources Investigations
Report 99-4204, Anchorage,
https://pubs.usgs.gov/wri/wri994204/pdf/wri994204.pdf (last access: 4 June 2019), 2000.
Brown, J., Ferrians Jr., O. J., Heginbottom, J. A., and Melnikov, E. S.:
Circum-Arctic map of permafrost and ground-ice conditions, Circum-Pacific
Map, https://doi.org/10.3133/cp45, 1997.
Buchwald, C. and Casciotti, K. L.: Oxygen isotopic fractionation and
exchange during bacterial nitrite oxidation, Limnol. Oceanogr.,
55, 1064–1074, https://doi.org/10.4319/lo.2010.55.3.1064, 2010.
Casciotti, K. L., Sigman, D. M., Galanter Hastings, M., Böhlke, J. K.,
and Kilkert, A.: Measurement of the Oxygen Isotopic Composition of Nitrate in
Seawater and Freshwater Using the Denitrifier Method, American Chemical
Society, https://doi.org/10.1021/AC020113W, 2002.
Chadburn, S. E., Burke, E. J., Cox, P. M., Friedlingstein, P., Hugelius, G., and Westermann, S.: An observation-based constraint on permafrost loss as a
function of global warming, Nat. Clim. Change, 7, 340–344,
https://doi.org/10.1038/nclimate3262, 2017.
Drake, T. W., Guillemette, F., Hemingway, J. D., Chanton, J. P., Podgorski,
D. C., Zimov, N. S., and Spencer, R. G. M.: The Ephemeral Signature of
Permafrost Carbon in an Arctic Fluvial Network, J. Geophys. Res.-Biogeo., 123, 1475–1485, https://doi.org/10.1029/2017JG004311,
2018.
Feng, D., Gleason, C. J., Lin, P., Yang, X., Pan, M., and Ishitsuka, Y.: Recent
changes to Arctic river discharge, Nat. Commun., 12, 6917, https://doi.org/10.1038/s41467-021-27228-1, 2021.
Francis, A., Ganeshram, R., Tuerena, R., Spencer, R. G. M., Holmes, R. M., Rogers, J. A., and Mahaffey, C.: Nitrogen isotope measurements from Arctic rivers and permafrost degradation sites, February 2017–September 2018, NERC EDS British Oceanographic Data Centre NOC, [data set], https://doi.org/10.5285/e777252b-b44a-7978-e053-6c86abc0d89f, 2022.
Frey, K. E., McClelland, J. W., Holmes, R. M., and Smith, L. G.: Impacts of
climate warming and permafrost thaw on the riverine transport of nitrogen
and phosphorus to the Kara Sea, J. Geophys. Res.-Biogeo., 112, 4–58, https://doi.org/10.1029/2006JG0003692, 2007.
Frey, K. E. and McClelland, J. W.: Impacts of permafrost degradation on
arctic river biogeochemistry, Hydrol. Proc., 23, 169–182, https://doi.org/10.1002/hyp.7196, 2009.
Frey, K. E. and Smith, L. C.: Amplified carbon release from vast West
Siberian peatlands by 2100, Geophys. Res. Lett., 32, L09401, https://doi.org/10.1029/2004GL022025, 2005.
Granger, J., Sigman, D. M., Needoba, J. A., and Harrison, P. J.: Coupled
nitrogen and oxygen isotope fractionation of nitrate during assimilation by
cultures of marine phytoplankton, Limnol. Oceanogr., 49,
1763–1773, https://doi.org/10.4319/LO.2004.49.5.1763, 2004.
Harms, T. K.: Permafrost thaw and a changing nitrogen cycle,
https://www.lter.uaf.edu/sympo/2013/FRI-1045_Harms.pdf (last access: 27 August 2019), 2013.
Hassol, S.: Impacts of a warming Arctic: Arctic Climate Impact Assessment,
Cambridge University Press,
https://www.amap.no/documents/doc/impacts-of-a-warming-arctic-2004/786 (last access: 22 November 2019), 2004.
Heikoop, J. M., Throckmorton, H. M., Newman, B. D., Perkins, G. B., Iversen,
C. M., Roy Chowdhury, T., Romanovsky, V., Graham, D. E., Norby, R. J.,
Wilson, C. J., and Wullschleger, S. D.: Isotopic identification of soil and
permafrost nitrate sources in an Arctic tundra ecosystem, J. Geophys. Res.-Biogeo., 120, 1000–1017, https://doi.org/10.1002/2014JG002883, 2015.
Holmes, R. M., Peterson, B. J., Gordeev, V. v., Zhulidov, A. v., Meybeck,
M., Lammers, R. B., and Vörösmarty, C. J.: Flux of nutrients from
Russian rivers to the Arctic Ocean: Can we establish a baseline against
which to judge future changes?, Water Resour. Res., 36, 2309–2320,
https://doi.org/10.1029/2000WR900099, 2000.
Holmes, R. M., McClelland, J. W., Peterson, B. J., Tank, S. E., Bulygina,
E., Eglinton, T. I., Gordeev, V. v., Gurtovaya, T. Y., Raymond, P. A.,
Repeta, D. J., Staples, R., Striegl, R. G., Zhulidov, A. V., and Zimov, S.
A.: Seasonal and Annual Fluxes of Nutrients and Organic Matter from Large
Rivers to the Arctic Ocean and Surrounding Seas, Estuar. Coasts,
35, 369–382, https://doi.org/10.1007/S12237-011-9386-6, 2012.
Holmes, R. M., McClelland, J. W., Tank, S. E., Spencer, R. G. M., and
Shiklomanov, A. I.: Arctic Great Rivers Observatory, Water Quality Dataset, [data set],
https://www.arcticgreatrivers.org/data (last access: 25 July 2019), 2021.
Hubberten, H. W., Andreev, A., Astakhov, V. I., Demidov, I., Dowdeswell, J.
A., Henriksen, M., Hjort, C., Houmark-Nielsen, M., Jakobsson, M., Kuzmina,
S., Larsen, E., Lunkka, J. P., Lyså, A., Mangerud, J., Möller, P.,
Saarnisto, M., Schirrmeister, L., Sher, A. V., Siegert, C., and Svendsen, J. I.:
The periglacial climate and environment in northern Eurasia during the Last
Glaciation, Quat. Sci. Rev., 23, 1333–1357, https://doi.org/10.1016/J.QUASCIREV.2003.12.012, 2004.
Hugelius, G., Loisel, J., Chadburn, S., Jackson, R. B., Jones, M.,
MacDonald, G., Marushchak, M., Olefeldt, D., Packalen, M., Siewert, M. B.,
Treat, C., Turetsky, M., Voigt, C., and Yu, Z.: Large stocks of peatland
carbon and nitrogen are vulnerable to permafrost thaw, P. Natl. Acad. Sci. USA, 117,
20438–20446, https://doi.org/10.1073/PNAS.1916387117, 2020.
Janjua, M. Y. and Tallman, R. F.: A mass-balanced Ecopath model of Great
Slave Lake to support an ecosystem approach to fisheries management:
Preliminary results, Canadian Technical Report of Fisheries and Aquatic
Sciences, Winnipeg, https://pdfs.semanticscholar.org/f34d/8748a5885b2a1b4a50edfbe01f97f4c5dbfe.pdf (last access: 27 August 2019),
2015.
Jones, J. B., Petrone, K. C., Finlay, J. C., Hinzman, L. D., and Bolton, W.
R.: Nitrogen loss from watersheds of interior Alaska underlain with
discontinuous permafrost, Geophys. Res. Lett., 32, 1–4, https://doi.org/10.1029/2004GL021734, 2005.
Knapp, A. N., Sigman, D. M., and Lipschultz, F.: N isotopic composition of
dissolved organic nitrogen and nitrate at the Bermuda Atlantic Time-series
Study site, Global Biogeochem. Cy., 19, 1–15, https://doi.org/10.1029/2004GB002320, 2005.
Loranty, M. M., Berner, L. T., Taber, E. D., Kropp, H., Natali, S. M.,
Alexander, H. D., Davydov, S. P., and Zimov, N. S.: Understory vegetation
mediates permafrost active layer dynamics and carbon dioxide fluxes in
open-canopy larch forests of northeastern Siberia, PLOS ONE, 13,
e0194014, https://doi.org/10.1371/JOURNAL.PONE.0194014, 2018.
McLean, R., Oswood, M. W., Irons III, J. G., and McDowell, W. H.: The
effect of permafrost on stream biogeochemistry: A case study of two streams
in the Alaskan (U.S.A.) taiga, Biogeochemistry, 47, 237–265,
https://doi.org/10.1023/A:1006142604714, 1999.
Mann, P. J., Davydova, A., Zimov, N., Spencer, R. G. M., Davydov, S.,
Bulygina, E., Zimov, S., and Holmes, R. M.: Controls on the composition and
lability of dissolved organic matter in Siberia's Kolyma River basin,
J. Geophys. Res.-Biogeo., 117, 1028, https://doi.org/10.1029/2011JG001798, 2012.
Mariotti, A., Germon, J. C., Hubert, P., Kaiser, P., Letolle, R., Tardieux,
A., and Tardieux, P.: Experimental determination of nitrogen kinetic
isotope fractionation: Some principles; illustration for the denitrification
and nitrification processes, Plant Soil, 62, 413–430, https://doi.org/10.1007/BF02374138, 1981.
McClelland, J. W., Déry, S. J., Peterson, B. J., Holmes, R. M., and Wood, E. F.: A pan-arctic evaluation of changes in river discharge during
the latter half of the 20th century, Geophys. Res. Lett., 33, 1–4,
https://doi.org/10.1029/2006GL025753, 2006.
McCrackin, M. L., Harrison, J. A., and Compton, J. E.: Factors influencing
export of dissolved inorganic nitrogen by major rivers: A new, seasonal,
spatially explicit, global model, Global Biogeochem. Cy.,
28, 269–285, https://doi.org/10.1002/2013GB004723, 2014.
McIlvin, M. R. and Casciotti, K. L.: Technical Updates to the Bacterial
Method for Nitrate Isotopic Analyses, Anal. Chem., 83, 1850–1856, https://doi.org/10.1021/ac1028984, 2011.
Nelson, F. E., Shiklomanov, N. I., Mueller, G. R., Hinkel, K. M., Walker, D.
A., and Bockheim, J. G.: Estimating active-layer thickness over a large
region: Kuparuk river basin, Alaska, U.S.A, Arctic Alpine Res.,
29, 367–378, https://doi.org/10.2307/1551985, 1997.
NOAA: Next Steps in Arctic Governance, Council of Councils,
https://councilofcouncils.cfr.org/global-memos/next-steps-arctic-governance (last access: 5 September 2019),
2014.
NSIDC: Climate and Frozen Ground – National Snow and Ice Data Center,
https://nsidc.org/cryosphere/frozenground/climate.html, (last access: 5 September 2019), 2018.
O'Donnell, J. A., Aiken, G. R., Swanson, D. K., Panda, S., Butler, K. D., and Baltensperger, A. P.: Dissolved organic matter composition of Arctic
rivers: Linking permafrost and parent material to riverine carbon, Global Biogeochem. Cy., 30, 1811–1826, https://doi.org/10.1002/2016GB005482, 2016.
Peterson, B. J., Holmes, R. M., McClelland, J. W., Vörösmarty, C.
J., Lammers, R. B., Shiklomanov, A. I., Shiklomanov, I. A., and Rahmstorf,
S.: Increasing river discharge to the Arctic Ocean, Science, 298,
2171–2173, https://doi.org/10.1126/SCIENCE.1077445, 2002.
Repo, M. E., Susiluoto, S., Lind, S. E., Jokinen, S., Elsakov, V., Biasi,
C., Virtanen, T., and Martikainen, P. J.: LargeN2O emissions from
cryoturbated peat soil in tundra, Nat. Geosci., 2,
189–192, https://doi.org/10.1038/ngeo434, 2009.
Schirrmeister, L., Kunitsky, V., Grosse, G., Wetterich, S., Meyer, H.,
Schwamborn, G., Babiy, O., Derevyagin, A., and Siegert, C.: Sedimentary
characteristics and origin of the Late Pleistocene Ice Complex on north-east
Siberian Arctic coastal lowlands and islands – A review, Quat.
Int., 241, 3–25, https://doi.org/10.1016/J.QUAINT.2010.04.004, 2011.
Schuur, E. A. G., Bockheim, J., Canadell, J. G., Euskirchen, E., Field, C.
B., Goryachkin, S. V., Hagemann, S., Kuhry, P., Lafleur, P. M., Lee, H.,
Mazhitova, G., Nelson, F. E., Rinke, A., Romanovsky, V. E., Shiklomanov, N.,
Tarnocai, C., Venevsky, S., Vogel, J. G., and Zimov, S. A.: Vulnerability
of Permafrost Carbon to Climate Change: Implications for the Global Carbon
Cycle, BioScience, 58, 701–714, https://doi.org/10.1641/B580807, 2008.
Schuur, E. A. G., Vogel, J. G., Crummer, K. G., Lee, H., Sickman, J. O., and Osterkamp, T. E.: The effect of permafrost thaw on old carbon release
and net carbon exchange from tundra, Nature, 459,
556–559, https://doi.org/10.1038/nature08031, 2009.
Shiklomanov, A. I., Yakovleva, T. I., Lammers, R. B., Karasev, I. Ph.,
Vörösmarty, C. J., and Linder, E.: Cold region river discharge
uncertainty-estimates from large Russian rivers, J. Hydrol., 326,
231–256, https://doi.org/10.1016/j.jhydrol.2005.10.037, 2006.
Sigman, D. M., Casciotti, K. L., Andreani, M., Barford, C., Galanter, M., and Böhlke, J. K.: A bacterial method for the nitrogen isotopic
analysis of nitrate in seawater and freshwater, Anal. Chem.,
73, 4145–4153, https://doi.org/10.1021/AC010088E, 2001.
Sigman, D. M., Granger, J., DiFiore, P. J., Lehmann, M. M., Ho, R., Cane,
G., and van Geen, A.: Coupled nitrogen and oxygen isotope measurements of
nitrate along the eastern North Pacific margin, Global Biogeochem. Cy., 19, 1–14, https://doi.org/10.1029/2005GB002458, 2005.
Sigman, D. M., DiFiore, P. J., Hain, M. P., Deutsch, C., Wang, Y., Karl, D.
M., Knapp, A. N., Lehmann, M. F., and Pantoja, S.: The dual isotopes of
deep nitrate as a constraint on the cycle and budget of oceanic fixed
nitrogen, Deep Sea Res. Pt. I, 56,
1419–1439, https://doi.org/10.1016/J.DSR.2009.04.007, 2009.
Sigman, D. M. and Casciotti, K. L.: Nitrogen Isotopes In The Ocean, Enc. Ocean Sci., 2001, 1884–1894, https://doi.org/10.1006/rwos.2001.0172, 2001.
Sipler, R. E. and Bronk, D. A.: Dynamics of Dissolved Organic Nitrogen,
Biogeochemistry of Marine Dissolved Organic Matter, Academic Press,
127–232, https://doi.org/10.1016/B978-0-12-405940-5.00004-2, 2015.
Spencer, R. G. M., Mann, P. J., Dittmar, T., Eglinton, T. I., McIntyre, C.,
Holmes, R. M., Zimov, N., and Stubbins, A.: Detecting the signature of
permafrost thaw in Arctic rivers, Geophys. Res. Lett., 42,
2830–2835, https://doi.org/10.1002/2015GL063498, 2015.
Streletskiy, D., Anisimov, O., and Vasiliev, A.: Permafrost Degradation, Snow
and Ice-Related Hazards, Risks Disast., 10, 303–344, 2015.
Struck, U.: On The Use of Stable Nitrogen Isotopes in Present and Past Anoxic Environments, edited by: Altenbach, A., Bernhard, J., and Seckbach, J., Anoxia, Cellular Origin, Life in Extreme Habitats and Astrobiology, 21, Springer, 497–513, Dordrecht, 2012 https://doi.org/10.1007/978-94-007-1896-8_26, 2012.
Swart, P., Evans, S. and Capo, T.: The Origin of Nitrogen Isotope Values in
Algae, Miami,
https://floridadep.gov/rcp/coral/documents/lbsp-project-32a-origin-nitrogen-isotope-values-algae (last access: 18 September 2019), 2008.
Tank, S. E., Manizza, M., Holmes, R. M., McClelland, J. W., and Peterson,
B. J.: The Processing and Impact of Dissolved Riverine Nitrogen in the
Arctic Ocean, Estuar. Coasts, 35, 401–415, https://doi.org/10.1007/S12237-011-9417-3, 2012.
Thibodeau, B., Miyajima, T., Tayasu, I., Wyatt, A. S. J., Watanabe, A.:
Morimoto, N., Yoshimizu, C., and Nagata, T., Heterogeneous dissolved
organic nitrogen supply over a coral reef: First evidence from nitrogen
stable isotope ratios, Coral Reefs, 32, 1103–1110, https://doi.org/10.1007/S00338-013-1070-9, 2013.
Thibodeau, B., Bauch, D., and Voss, M.: Nitrogen dynamic in Eurasian coastal
Arctic ecosystem: Insight from nitrogen isotope, Global Biogeochem. Cy., 31, 836–849, https://doi.org/10.1002/2016GB005593, 2017.
Tye, A. M. and Heaton, T. H. E.: Chemical and isotopic characteristics of
weathering and nitrogen release in non-glacial drainage waters on Arctic
tundra, Geochim. Cosmochim. Ac., 71, 4188–4205, https://doi.org/10.1016/j.gca.2007.06.040, 2007.
UNFCCC: Adoption of the Paris Agreement,
https://unfccc.int/resource/docs/2015/cop21/eng/l09r01.pdf (last access: 2 September 2019), 2015.
Vasil'chuk, Y. K., Vasil'chuk, A. C., Rank, D., Kutschera, W., and Kim, J.
C.: Radiocarbon Dating of δ18O-δD Plots in Late Pleistocene
Ice-Wedges of the Duvanny Yar (Lower Kolyma River, Northern Yakutia),
Radiocarbon, 43, 541–553, https://doi.org/10.1017/S0033822200041199, 2001.
Van Everdingen, R. O.: Multi-language glossary of permafrost and related
ground-ice terms: in Chinese, English, French, German, Icelandic, Italian,
Norwegian, Polish, Romanian, Russian, Spanish, and Swedish, Calgary: Arctic
Institute of North America, 1, p. 78, https://globalcryospherewatch.org/reference/glossary_docs/Glossary_of_Permafrost_and_Ground-Ice_IPA_2005.pdf (last access: 28 October 2022),
1998.
Voigt, C., Marushchak, M. E., Lamprecht, R. E., Jackowicz-Korczyński,
M., Lindgren, A., Mastepanov, M., Granlund, L., Christensen, T. R.,
Tahvanainen, T., Martikainen, P. J., and Biasi, C.: Increased nitrous oxide
emissions from Arctic peatlands after permafrost thaw, P. Natl. Acad. Sci. USA, 114,
6238–6243, https://doi.org/10.1073/PNAS.1702902114, 2017.
Vonk, J. E., Sanchez-Garca, 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, A.: Activation of old
carbon by erosion of coastal and subsea permafrost in Arctic Siberia, Nature
489, 137–140, https://doi.org/10.1038/nature11392, 2012.
Vonk, J. E., Mann, P. J., Dowdy, K. L., Davydova, A., Davydov, S. P., Zimov,
N., Spencer, R. G. M., Bulygina, E. B., Eglinton, T. I., and Holmes, R. M.:
Dissolved organic carbon loss from Yedoma permafrost amplified by ice wedge
thaw, Environ. Res. Lett., 8, 035023, https://doi.org/10.1088/1748-9326/8/3/035023, 2013.
Vonk, J. E., Mann, P. J., Davydov, S., Davydova, A., Spencer, R. G. M.,
Schade, J., Sobczak, W. V., Zimov, N., Zimov, S., Bulygina, E., Eglinton, T.
I., and Holmes, R. M.: High biolability of ancient permafrost carbon upon
thaw, Geophys. Res. Lett., 40, 2689–2693, https://doi.org/10.1002/GRL.50348, 2013.
Walvoord, M. A. and Striegl, R. G.: Increased groundwater to stream
discharge from permafrost thawing in the Yukon River basin: Potential
impacts on lateral export of carbon and nitrogen, Geophys. Res. Lett., 34, L12402, https://doi.org/10.1029/2007GL030216, 2007.
Wankel, S. D., Kendall, C., Pennington, J. T., Chavez, F. P., Paytan, A.,
Wankel, C.:, Kendall, C., Pennington, J. T., Chavez, F. P., and Paytan,
A.: Nitrification in the euphotic zone as evidenced by nitrate dual isotopic
composition: Observations from Monterey Bay, California, Global
Biogeochem. Cy., 21, GB2009, https://doi.org/10.1029/2006GB002723, 2007.
Weigand, M. A., Foriel, J., Barnett, B., Oleynik, S., and Sigman, D. M.:
Updates to instrumentation and protocols for isotopic analysis of nitrate by
the denitrifier method, Rapid Commun. Mass Spec., 30,
1365–1383, https://doi.org/10.1002/RCM.7570, 2016.
Wild, B., Andersson, A., Bröder, L., Vonk, J., Hugelius, G., McClelland,
J. W., Song, W., Raymond, P. A., and Gustafsson, Ö.: Rivers across the
Siberian Arctic unearth the patterns of carbon release from thawing
permafrost, P. Natl. Acad. Sci. USA, 116, 10280–10285, https://doi.org/10.1073/PNAS.1811797116, 2019.
Yi, Y., Gibson, J. J., Cooper, L. W., Hélie, J. F., Birks, S. J.,
McClelland, J. W., Holmes, R. M., and Peterson, B. J.: Isotopic signals
(18O, 2H, 3H) of six major rivers draining the pan-Arctic watershed, Global
Biogeochem. Cy., 26, GB1027, https://doi.org/10.1029/2011GB004159, 2012.
Co-editor-in-chief
Vast areas of permafrost are being degraded by climate change, which can release substantial quantities of nutrients into rivers and the ocean. This study shows how nitrogen isotopes can be used to determine how climate change affects the fluxes of nitrogen to the Arctic Ocean through permafrost melt.
Vast areas of permafrost are being degraded by climate change, which can release substantial...
Short summary
Climate change is causing extensive permafrost degradation and nutrient releases into rivers with great ecological impacts on the Arctic Ocean. We focused on nitrogen (N) release from this degradation and associated cycling using N isotopes, an understudied area. Many N species are released at degradation sites with exchanges between species. N inputs from permafrost degradation and seasonal river N trends were identified using isotopes, helping to predict climate change impacts.
Climate change is causing extensive permafrost degradation and nutrient releases into rivers...
Altmetrics
Final-revised paper
Preprint