Articles | Volume 14, issue 9
https://doi.org/10.5194/bg-14-2481-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-14-2481-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
17 May 2017
Research article |
| 17 May 2017
Long-term carbon and nitrogen dynamics at SPRUCE revealed through stable isotopes in peat profiles
Earth Systems Research Center, University of New Hampshire, Durham,
New Hampshire, 03824, USA
Janet Chen
Earth Systems Research Center, University of New Hampshire, Durham,
New Hampshire, 03824, USA
Soil and Water Management & Crop Nutrition Laboratory, FAO/IAEA
Agriculture & Biotechnology Laboratories, Seibersdorf, Austria
Paul J. Hanson
Climate Change Science Institute and Environmental Sciences Division,
Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
Colleen M. Iversen
Climate Change Science Institute and Environmental Sciences Division,
Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831, USA
Karis J. McFarlane
Center for Accelerator Mass Spectrometry, Lawrence Livermore National
Laboratory, Livermore, California, 94551, USA
Nathan R. Thorp
Earth Systems Research Center, University of New Hampshire, Durham,
New Hampshire, 03824, USA
Kirsten S. Hofmockel
Department of Ecology, Evolution and Organismal Biology, Iowa State
University, Ames, Iowa, 50011, USA
Pacific Northwest National Laboratory, Richland, Washington, 99354, USA
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Alexandra Hedgpeth, Alison M. Hoyt, Kyle C. Cavanaugh, Karis J. McFarlane, and Daniela F. Cusack
Biogeosciences, 22, 2667–2690, https://doi.org/10.5194/bg-22-2667-2025, https://doi.org/10.5194/bg-22-2667-2025, 2025
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Tropical peatlands store ancient carbon and have been identified as both being vulnerable to future climate change and taking a long time to recover after a disturbance. It is unknown if these gases are produced from decomposition of 1000-year-old peat. Radiocarbon dating shows emitted gases are young, indicating that surface carbon (rather than old peat) drives emissions. Preserving these ecosystems can trap old carbon, mitigating climate change.
Claire L. Bachand, Chen Wang, Baptiste Dafflon, Lauren N. Thomas, Ian Shirley, Sarah Maebius, Colleen M. Iversen, and Katrina E. Bennett
The Cryosphere, 19, 393–400, https://doi.org/10.5194/tc-19-393-2025, https://doi.org/10.5194/tc-19-393-2025, 2025
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Temporally continuous snow depth estimates are important for understanding changing snow patterns and impacts on frozen ground in the Arctic. In this work, we developed an approach to predict snow depth from variability in snow–ground interface temperature using small temperature sensors that are cheap and easy to deploy. This new technique enables spatially distributed and temporally continuous snowpack monitoring that has not previously been possible.
Katherine E. Grant, Marisa N. Repasch, Kari M. Finstad, Julia D. Kerr, Maxwell Marple, Christopher J. Larson, Taylor A. B. Broek, Jennifer Pett-Ridge, and Karis J. McFarlane
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Soils store organic carbon composed of multiple compounds from plants and microbes for different lengths of time. To understand how soils store these different carbon types, we measure the time each carbon fraction is in a grassland soil profile. Our results show that the length of time each individual soil fraction is in our soil changes. Our approach allows a detailed look at the different components in soils. This study can help improve our understanding of soil dynamics.
Katrina E. Bennett, Greta Miller, Robert Busey, Min Chen, Emma R. Lathrop, Julian B. Dann, Mara Nutt, Ryan Crumley, Shannon L. Dillard, Baptiste Dafflon, Jitendra Kumar, W. Robert Bolton, Cathy J. Wilson, Colleen M. Iversen, and Stan D. Wullschleger
The Cryosphere, 16, 3269–3293, https://doi.org/10.5194/tc-16-3269-2022, https://doi.org/10.5194/tc-16-3269-2022, 2022
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In the Arctic and sub-Arctic, climate shifts are changing ecosystems, resulting in alterations in snow, shrubs, and permafrost. Thicker snow under shrubs can lead to warmer permafrost because deeper snow will insulate the ground from the cold winter. In this paper, we use modeling to characterize snow to better understand the drivers of snow distribution. Eventually, this work will be used to improve models used to study future changes in Arctic and sub-Arctic snow patterns.
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.
Karis J. McFarlane, Heather M. Throckmorton, Jeffrey M. Heikoop, Brent D. Newman, Alexandra L. Hedgpeth, Marisa N. Repasch, Thomas P. Guilderson, and Cathy J. Wilson
Biogeosciences, 19, 1211–1223, https://doi.org/10.5194/bg-19-1211-2022, https://doi.org/10.5194/bg-19-1211-2022, 2022
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Planetary warming is increasing seasonal thaw of permafrost, making this extensive old carbon stock vulnerable. In northern Alaska, we found more and older dissolved organic carbon in small drainages later in summer as more permafrost was exposed by deepening thaw. Younger and older carbon did not differ in chemical indicators related to biological lability suggesting this carbon can cycle through aquatic systems and contribute to greenhouse gas emissions as warming increases permafrost thaw.
Xin Huang, Dan Lu, Daniel M. Ricciuto, Paul J. Hanson, Andrew D. Richardson, Xuehe Lu, Ensheng Weng, Sheng Nie, Lifen Jiang, Enqing Hou, Igor F. Steinmacher, and Yiqi Luo
Geosci. Model Dev., 14, 5217–5238, https://doi.org/10.5194/gmd-14-5217-2021, https://doi.org/10.5194/gmd-14-5217-2021, 2021
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In the data-rich era, data assimilation is widely used to integrate abundant observations into models to reduce uncertainty in ecological forecasting. However, applications of data assimilation are restricted by highly technical requirements. To alleviate this technical burden, we developed a model-independent data assimilation (MIDA) module which is friendly to ecologists with limited programming skills. MIDA also supports a flexible switch of different models or observations in DA analysis.
Rafael Poyatos, Víctor Granda, Víctor Flo, Mark A. Adams, Balázs Adorján, David Aguadé, Marcos P. M. Aidar, Scott Allen, M. Susana Alvarado-Barrientos, Kristina J. Anderson-Teixeira, Luiza Maria Aparecido, M. Altaf Arain, Ismael Aranda, Heidi Asbjornsen, Robert Baxter, Eric Beamesderfer, Z. Carter Berry, Daniel Berveiller, Bethany Blakely, Johnny Boggs, Gil Bohrer, Paul V. Bolstad, Damien Bonal, Rosvel Bracho, Patricia Brito, Jason Brodeur, Fernando Casanoves, Jérôme Chave, Hui Chen, Cesar Cisneros, Kenneth Clark, Edoardo Cremonese, Hongzhong Dang, Jorge S. David, Teresa S. David, Nicolas Delpierre, Ankur R. Desai, Frederic C. Do, Michal Dohnal, Jean-Christophe Domec, Sebinasi Dzikiti, Colin Edgar, Rebekka Eichstaedt, Tarek S. El-Madany, Jan Elbers, Cleiton B. Eller, Eugénie S. Euskirchen, Brent Ewers, Patrick Fonti, Alicia Forner, David I. Forrester, Helber C. Freitas, Marta Galvagno, Omar Garcia-Tejera, Chandra Prasad Ghimire, Teresa E. Gimeno, John Grace, André Granier, Anne Griebel, Yan Guangyu, Mark B. Gush, Paul J. Hanson, Niles J. Hasselquist, Ingo Heinrich, Virginia Hernandez-Santana, Valentine Herrmann, Teemu Hölttä, Friso Holwerda, James Irvine, Supat Isarangkool Na Ayutthaya, Paul G. Jarvis, Hubert Jochheim, Carlos A. Joly, Julia Kaplick, Hyun Seok Kim, Leif Klemedtsson, Heather Kropp, Fredrik Lagergren, Patrick Lane, Petra Lang, Andrei Lapenas, Víctor Lechuga, Minsu Lee, Christoph Leuschner, Jean-Marc Limousin, Juan Carlos Linares, Maj-Lena Linderson, Anders Lindroth, Pilar Llorens, Álvaro López-Bernal, Michael M. Loranty, Dietmar Lüttschwager, Cate Macinnis-Ng, Isabelle Maréchaux, Timothy A. Martin, Ashley Matheny, Nate McDowell, Sean McMahon, Patrick Meir, Ilona Mészáros, Mirco Migliavacca, Patrick Mitchell, Meelis Mölder, Leonardo Montagnani, Georgianne W. Moore, Ryogo Nakada, Furong Niu, Rachael H. Nolan, Richard Norby, Kimberly Novick, Walter Oberhuber, Nikolaus Obojes, A. Christopher Oishi, Rafael S. Oliveira, Ram Oren, Jean-Marc Ourcival, Teemu Paljakka, Oscar Perez-Priego, Pablo L. Peri, Richard L. Peters, Sebastian Pfautsch, William T. Pockman, Yakir Preisler, Katherine Rascher, George Robinson, Humberto Rocha, Alain Rocheteau, Alexander Röll, Bruno H. P. Rosado, Lucy Rowland, Alexey V. Rubtsov, Santiago Sabaté, Yann Salmon, Roberto L. Salomón, Elisenda Sánchez-Costa, Karina V. R. Schäfer, Bernhard Schuldt, Alexandr Shashkin, Clément Stahl, Marko Stojanović, Juan Carlos Suárez, Ge Sun, Justyna Szatniewska, Fyodor Tatarinov, Miroslav Tesař, Frank M. Thomas, Pantana Tor-ngern, Josef Urban, Fernando Valladares, Christiaan van der Tol, Ilja van Meerveld, Andrej Varlagin, Holm Voigt, Jeffrey Warren, Christiane Werner, Willy Werner, Gerhard Wieser, Lisa Wingate, Stan Wullschleger, Koong Yi, Roman Zweifel, Kathy Steppe, Maurizio Mencuccini, and Jordi Martínez-Vilalta
Earth Syst. Sci. Data, 13, 2607–2649, https://doi.org/10.5194/essd-13-2607-2021, https://doi.org/10.5194/essd-13-2607-2021, 2021
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Transpiration is a key component of global water balance, but it is poorly constrained from available observations. We present SAPFLUXNET, the first global database of tree-level transpiration from sap flow measurements, containing 202 datasets and covering a wide range of ecological conditions. SAPFLUXNET and its accompanying R software package
sapfluxnetrwill facilitate new data syntheses on the ecological factors driving water use and drought responses of trees and forests.
Xiaoying Shi, Daniel M. Ricciuto, Peter E. Thornton, Xiaofeng Xu, Fengming Yuan, Richard J. Norby, Anthony P. Walker, Jeffrey M. Warren, Jiafu Mao, Paul J. Hanson, Lin Meng, David Weston, and Natalie A. Griffiths
Biogeosciences, 18, 467–486, https://doi.org/10.5194/bg-18-467-2021, https://doi.org/10.5194/bg-18-467-2021, 2021
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The Sphagnum mosses are the important species of a wetland ecosystem. To better represent the peatland ecosystem, we introduced the moss species to the land model component (ELM) of the Energy Exascale Earth System Model (E3SM) by developing water content dynamics and nonvascular photosynthetic processes for moss. We tested the model against field observations and used the model to make projections of the site's carbon cycle under warming and atmospheric CO2 concentration scenarios.
Corey R. Lawrence, Jeffrey Beem-Miller, Alison M. Hoyt, Grey Monroe, Carlos A. Sierra, Shane Stoner, Katherine Heckman, Joseph C. Blankinship, Susan E. Crow, Gavin McNicol, Susan Trumbore, Paul A. Levine, Olga Vindušková, Katherine Todd-Brown, Craig Rasmussen, Caitlin E. Hicks Pries, Christina Schädel, Karis McFarlane, Sebastian Doetterl, Christine Hatté, Yujie He, Claire Treat, Jennifer W. Harden, Margaret S. Torn, Cristian Estop-Aragonés, Asmeret Asefaw Berhe, Marco Keiluweit, Ágatha Della Rosa Kuhnen, Erika Marin-Spiotta, Alain F. Plante, Aaron Thompson, Zheng Shi, Joshua P. Schimel, Lydia J. S. Vaughn, Sophie F. von Fromm, and Rota Wagai
Earth Syst. Sci. Data, 12, 61–76, https://doi.org/10.5194/essd-12-61-2020, https://doi.org/10.5194/essd-12-61-2020, 2020
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The International Soil Radiocarbon Database (ISRaD) is an an open-source archive of soil data focused on datasets including radiocarbon measurements. ISRaD includes data from bulk or
whole soils, distinct soil carbon pools isolated in the laboratory by a variety of soil fractionation methods, samples of soil gas or water collected interstitially from within an intact soil profile, CO2 gas isolated from laboratory soil incubations, and fluxes collected in situ from a soil surface.
Junyi Liang, Gangsheng Wang, Daniel M. Ricciuto, Lianhong Gu, Paul J. Hanson, Jeffrey D. Wood, and Melanie A. Mayes
Geosci. Model Dev., 12, 1601–1612, https://doi.org/10.5194/gmd-12-1601-2019, https://doi.org/10.5194/gmd-12-1601-2019, 2019
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Soil respiration, the second largest carbon fluxes between the atmosphere and land, is not well represented in global land models. In this study, using long-term observations at a temperate forest, we identified a solution for using better soil water potential simulations to improve predictions of soil respiration in the E3SM land model. In addition, parameter calibration further improved model performance.
Yuanyuan Huang, Mark Stacy, Jiang Jiang, Nilutpal Sundi, Shuang Ma, Volodymyr Saruta, Chang Gyo Jung, Zheng Shi, Jianyang Xia, Paul J. Hanson, Daniel Ricciuto, and Yiqi Luo
Geosci. Model Dev., 12, 1119–1137, https://doi.org/10.5194/gmd-12-1119-2019, https://doi.org/10.5194/gmd-12-1119-2019, 2019
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Predicting future changes in ecosystem services is not only highly desirable but is also becoming feasible as several forces are converging to transform ecological research into quantitative forecasting. To realize ecological forecasting, we have developed an Ecological Platform for Assimilating Data (EcoPAD) into models. EcoPAD also has the potential to become an interactive tool for resource management, stimulate citizen science in ecology, and transform environmental education.
Misha B. Krassovski, Glen E. Lyon, Jeffery S. Riggs, and Paul J. Hanson
Geosci. Instrum. Method. Data Syst., 7, 289–295, https://doi.org/10.5194/gi-7-289-2018, https://doi.org/10.5194/gi-7-289-2018, 2018
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Climate change studies are growing and related experiments are getting bigger and more complex. They are often conducted in remote areas where communications are limited. In cases like that the data can be transferred via a satellite connection, but these types of connections are slow. We found that by using the little known possibilities of LoggerNet software (the most popular data logger software in environmental science) it is possible to transfer quite a large amount of data.
Paul J. Hanson, Jeffery S. Riggs, W. Robert Nettles, Jana R. Phillips, Misha B. Krassovski, Leslie A. Hook, Lianhong Gu, Andrew D. Richardson, Donald M. Aubrecht, Daniel M. Ricciuto, Jeffrey M. Warren, and Charlotte Barbier
Biogeosciences, 14, 861–883, https://doi.org/10.5194/bg-14-861-2017, https://doi.org/10.5194/bg-14-861-2017, 2017
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This paper describes operational methods to achieve whole-ecosystem warming (WEW) for tall-stature, high-carbon, boreal forest peatlands. The methods enable scientists to study immediate and longer-term (1 decade) responses of organisms (microbes to trees) and ecosystem functions (carbon, water and nutrient cycles). The WEW technology allows researchers to have a plausible glimpse of future environmental conditions for study that are not available in the current observational record.
Jitendra Kumar, Nathan Collier, Gautam Bisht, Richard T. Mills, Peter E. Thornton, Colleen M. Iversen, and Vladimir Romanovsky
The Cryosphere, 10, 2241–2274, https://doi.org/10.5194/tc-10-2241-2016, https://doi.org/10.5194/tc-10-2241-2016, 2016
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Microtopography of the low-gradient polygonal tundra plays a critical role in these ecosystem; however, patterns and drivers are poorly understood. A modeling-based approach was developed in this study to characterize and represent the permafrost soils in the model and simulate the thermal dynamics using a mechanistic high-resolution model. Results shows the ability of the model to simulate the patterns and variability of thermal regimes and improve our understanding of polygonal tundra.
J. Mao, D. M. Ricciuto, P. E. Thornton, J. M. Warren, A. W. King, X. Shi, C. M. Iversen, and R. J. Norby
Biogeosciences, 13, 641–657, https://doi.org/10.5194/bg-13-641-2016, https://doi.org/10.5194/bg-13-641-2016, 2016
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The aim of this study is to implement, calibrate and evaluate the CLM4 against carbon and hydrology observations from a shading and labeling experiment in a stand of young loblolly pines. We found a combination of parameters measured on-site and calibration targeting biomass, transpiration, and 13C discrimination gave good agreement with pretreatment measurements. We also used observations from the experiment to develop a conceptual model of short-term photosynthate storage and transport.
C. L. Phillips, K. J. McFarlane, D. Risk, and A. R. Desai
Biogeosciences, 10, 7999–8012, https://doi.org/10.5194/bg-10-7999-2013, https://doi.org/10.5194/bg-10-7999-2013, 2013
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Greenhouse gases are produced and consumed via a number of pathways. Quantifying these pathways helps reduce the climate and environmental footprint of anthropogenic activities. The contribution of the pathways can be estimated from the isotopic composition, which acts as a fingerprint for these pathways. We have developed the Time-resolved FRactionation And Mixing Evaluation (TimeFRAME) model to simplify interpretation and estimate the contribution of different pathways and their uncertainty.
Kim A. P. Faassen, Jordi Vilà-Guerau de Arellano, Raquel González-Armas, Bert G. Heusinkveld, Ivan Mammarella, Wouter Peters, and Ingrid T. Luijkx
Biogeosciences, 21, 3015–3039, https://doi.org/10.5194/bg-21-3015-2024, https://doi.org/10.5194/bg-21-3015-2024, 2024
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The ratio between atmospheric O2 and CO2 can be used to characterize the carbon balance at the surface. By combining a model and observations from the Hyytiälä forest (Finland), we show that using atmospheric O2 and CO2 measurements from a single height provides a weak constraint on the surface CO2 exchange because large-scale processes such as entrainment confound this signal. We therefore recommend always using multiple heights of O2 and CO2 measurements to study surface CO2 exchange.
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
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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
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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
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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
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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
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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
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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
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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
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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.
Adam Francis, Raja S. Ganeshram, Robyn E. Tuerena, Robert G. M. Spencer, Robert M. Holmes, Jennifer A. Rogers, and Claire Mahaffey
Biogeosciences, 20, 365–382, https://doi.org/10.5194/bg-20-365-2023, https://doi.org/10.5194/bg-20-365-2023, 2023
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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.
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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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.
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Short summary
We measured carbon and nitrogen isotope ratios (13C : 12C and 15N : 14N) in peat cores in a northern Minnesota bog to understand how climate, vegetation type, and decomposition affected C and N budgets over the last 9000 years. 13C : 12C patterns were primarily influenced by shifts in temperature, peatland vegetation and atmospheric CO2, whereas tree colonization and upland N influxes affected 15N : 14N ratios. Isotopic markers provided new insights into long-term patterns of CO2 and nitrogen losses.
We measured carbon and nitrogen isotope ratios (13C : 12C and 15N : 14N) in peat cores in a...
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