Articles | Volume 14, issue 1
https://doi.org/10.5194/bg-14-73-2017
© 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-14-73-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
06 Jan 2017
Research article |
| 06 Jan 2017
Plant water resource partitioning and isotopic fractionation during transpiration in a seasonally dry tropical climate
Lien De Wispelaere
CORRESPONDING AUTHOR
Isotope Bioscience Laboratory – ISOFYS, Faculty of Bioscience
Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
Samuel Bodé
Isotope Bioscience Laboratory – ISOFYS, Faculty of Bioscience
Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
Pedro Hervé-Fernández
Isotope Bioscience Laboratory – ISOFYS, Faculty of Bioscience
Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
Laboratory of Hydrology and Water Management, Faculty of Bioscience
Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
Andreas Hemp
Department of Plant Systematics, University of Bayreuth, 95440
Bayreuth, Germany
Dirk Verschuren
Limnology Unit, Department of Biology, Ghent University,
Ledeganckstraat 35, 9000 Gent, Belgium
Pascal Boeckx
Isotope Bioscience Laboratory – ISOFYS, Faculty of Bioscience
Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium
Related authors
No articles found.
Antoine de Clippele, Astrid C. H. Jaeger, Simon Baumgartner, Marijn Bauters, Pascal Boeckx, Clement Botefa, Glenn Bush, Jessica Carilli, Travis W. Drake, Christian Ekamba, Gode Lompoko, Nivens Bey Mukwiele, Kristof Van Oost, Roland A. Werner, Joseph Zambo, Johan Six, and Matti Barthel
Biogeosciences, 22, 3011–3027, https://doi.org/10.5194/bg-22-3011-2025, https://doi.org/10.5194/bg-22-3011-2025, 2025
Short summary
Short summary
Tropical forest soils as a large terrestrial source of carbon dioxide (CO2) contribute to the global greenhouse gas budget. Despite this, carbon flux data from forested wetlands are scarce in tropical Africa. The study presents 3 years of semi-continuous measurements of surface CO2 fluxes within the Congo Basin. Although no seasonal patterns were evident, our results show a positive effect of soil temperature and moisture, while a quadratic relationship was observed with the water table.
Derrick Muheki, Bas Vercruysse, Krishna Kumar Thirukokaranam Chandrasekar, Christophe Verbruggen, Julie M. Birkholz, Koen Hufkens, Hans Verbeeck, Pascal Boeckx, Seppe Lampe, Ed Hawkins, Peter Thorne, Dominique Kankonde Ntumba, Olivier Kapalay Moulasa, and Wim Thiery
EGUsphere, https://doi.org/10.5194/egusphere-2024-3779, https://doi.org/10.5194/egusphere-2024-3779, 2025
This preprint is open for discussion and under review for Geoscientific Model Development (GMD).
Short summary
Short summary
Archives worldwide host vast records of observed weather data crucial for understanding climate variability. However, most of these records are still in paper form, limiting their use. To address this, we developed MeteoSaver, an open-source tool, to transcribe these records to machine-readable format. Applied to ten handwritten temperature sheets, it achieved a median accuracy of 74%. This tool offers a promising solution to preserve records from archives and unlock historical weather insights.
Marius Buydens, Emil De Borger, Lorenz Meire, Samuel Bodé, Antonio Schirone, Karline Soetaert, Ann Vanreusel, and Ulrike Braeckman
EGUsphere, https://doi.org/10.5194/egusphere-2025-102, https://doi.org/10.5194/egusphere-2025-102, 2025
Short summary
Short summary
As the Greenland Ice Sheet retreats, it is important to understand how this impacts the carbon burial in Greenland fjords. By comparing a fjord with marine-terminating glaciers versus one fed by a land-terminating glacier, we see that the productive waters associated to marine-terminating glaciers not necessary lead to enhanced carbon burial. Instead, we highlight the complex interplay of physical, biological, and sedimentary processes that mediate carbon dynamics in these fjords.
Aurora Patchett, Louise Rütting, Tobias Rütting, Samuel Bodé, Sara Hallin, Jaanis Juhanson, C. Florian Stange, Mats P. Björkman, Pascal Boeckx, Gunhild Rosqvist, and Robert G. Björk
EGUsphere, https://doi.org/10.5194/egusphere-2025-2179, https://doi.org/10.5194/egusphere-2025-2179, 2025
Short summary
Short summary
This study explores how different types of fungi and plant species affect nitrogen cycling in Arctic soils. By removing certain plants, we found that fungi associated with shrubs speed up nitrogen processes more than those with grasses. Dominant plant species enhance nitrogen recycling, while rare species increase nitrogen loss. These findings help predict how Arctic ecosystems respond to climate change, highlighting the importance of fungi and plant diversity in regulating ecosystem processes.
Inês Vieira, Félicien Meunier, Maria Carolina Duran Rojas, Stephen Sitch, Flossie Brown, Giacomo Gerosa, Silvano Fares, Pascal Boeckx, Marijn Bauters, and Hans Verbeeck
EGUsphere, https://doi.org/10.5194/egusphere-2025-1375, https://doi.org/10.5194/egusphere-2025-1375, 2025
Short summary
Short summary
We used a computer model to study how ozone pollution reduces plant growth in six European forests, from Finland to Italy. Combining field data and simulations, we found that ozone can lower carbon uptake by up to 6 % each year, especially in Mediterranean areas. Our study shows that local climate and forest type influence ozone damage and highlights the need to include ozone effects in forest and climate models.
Roxanne Daelman, Marijn Bauters, Matti Barthel, Emmanuel Bulonza, Lodewijk Lefevre, José Mbifo, Johan Six, Klaus Butterbach-Bahl, Benjamin Wolf, Ralf Kiese, and Pascal Boeckx
Biogeosciences, 22, 1529–1542, https://doi.org/10.5194/bg-22-1529-2025, https://doi.org/10.5194/bg-22-1529-2025, 2025
Short summary
Short summary
The increase in atmospheric concentrations of several greenhouse gases (GHGs) since 1750 is attributed to human activity. However, natural ecosystems, such as tropical forests, also contribute to GHG budgets. The Congo Basin hosts the second largest tropical forest and is understudied. In this study, measurements of soil GHG exchange were carried out during 16 months in a tropical forest in the Congo Basin. Overall, the soil acted as a major source of CO2 and N2O and a minor sink of CH4.
Astrid Françoys, Orly Mendoza, Junwei Hu, Pascal Boeckx, Wim Cornelis, Stefaan De Neve, and Steven Sleutel
SOIL, 11, 121–140, https://doi.org/10.5194/soil-11-121-2025, https://doi.org/10.5194/soil-11-121-2025, 2025
Short summary
Short summary
To assess the impact of the groundwater table (GWT) depth on soil moisture and C mineralization, we designed a laboratory setup using 200 cm undisturbed soil columns. Surprisingly, the moisture increase induced by a shallower GWT did not result in enhanced C mineralization. We presume this upward capillary moisture effect was offset by increased C mineralization upon rewetting, particularly noticeable in drier soils when capillary rise affected the topsoil to a lesser extent due to a deeper GWT.
Flossie Brown, Gerd Folberth, Stephen Sitch, Paulo Artaxo, Marijn Bauters, Pascal Boeckx, Alexander W. Cheesman, Matteo Detto, Ninong Komala, Luciana Rizzo, Nestor Rojas, Ines dos Santos Vieira, Steven Turnock, Hans Verbeeck, and Alfonso Zambrano
Atmos. Chem. Phys., 24, 12537–12555, https://doi.org/10.5194/acp-24-12537-2024, https://doi.org/10.5194/acp-24-12537-2024, 2024
Short summary
Short summary
Ozone is a pollutant that is detrimental to human and plant health. Ozone monitoring sites in the tropics are limited, so models are often used to understand ozone exposure. We use measurements from the tropics to evaluate ozone from the UK Earth system model, UKESM1. UKESM1 is able to capture the pattern of ozone in the tropics, except in southeast Asia, although it systematically overestimates it at all sites. This work highlights that UKESM1 can capture seasonal and hourly variability.
Allix J. Baxter, Francien Peterse, Dirk Verschuren, Aihemaiti Maitituerdi, Nicolas Waldmann, and Jaap S. Sinninghe Damsté
Biogeosciences, 21, 2877–2908, https://doi.org/10.5194/bg-21-2877-2024, https://doi.org/10.5194/bg-21-2877-2024, 2024
Short summary
Short summary
This study investigates the impact of long-term lake-system evolution on the climate signal recorded by glycerol dialkyl glycerol tetraethers (GDGTs), a popular biomarker in paleoclimate research. It compares downcore changes in GDGTs in the 250 000 year sediment sequence of Lake Chala (Kenya/Tanzania) to independent data for lake mixing and water-column chemistry. These factors influence the GDGT proxies in the earliest depositional phases (before ~180 ka), confounding the climate signal.
Joseph Okello, Marijn Bauters, Hans Verbeeck, Samuel Bodé, John Kasenene, Astrid Françoys, Till Engelhardt, Klaus Butterbach-Bahl, Ralf Kiese, and Pascal Boeckx
Biogeosciences, 20, 719–735, https://doi.org/10.5194/bg-20-719-2023, https://doi.org/10.5194/bg-20-719-2023, 2023
Short summary
Short summary
The increase in global and regional temperatures has the potential to drive accelerated soil organic carbon losses in tropical forests. We simulated climate warming by translocating intact soil cores from higher to lower elevations. The results revealed increasing temperature sensitivity and decreasing losses of soil organic carbon with increasing elevation. Our results suggest that climate warming may trigger enhanced losses of soil organic carbon from tropical montane forests.
Flossie Brown, Gerd A. Folberth, Stephen Sitch, Susanne Bauer, Marijn Bauters, Pascal Boeckx, Alexander W. Cheesman, Makoto Deushi, Inês Dos Santos Vieira, Corinne Galy-Lacaux, James Haywood, James Keeble, Lina M. Mercado, Fiona M. O'Connor, Naga Oshima, Kostas Tsigaridis, and Hans Verbeeck
Atmos. Chem. Phys., 22, 12331–12352, https://doi.org/10.5194/acp-22-12331-2022, https://doi.org/10.5194/acp-22-12331-2022, 2022
Short summary
Short summary
Surface ozone can decrease plant productivity and impair human health. In this study, we evaluate the change in surface ozone due to climate change over South America and Africa using Earth system models. We find that if the climate were to change according to the worst-case scenario used here, models predict that forested areas in biomass burning locations and urban populations will be at increasing risk of ozone exposure, but other areas will experience a climate benefit.
Caroline C. Clason, Will H. Blake, Nick Selmes, Alex Taylor, Pascal Boeckx, Jessica Kitch, Stephanie C. Mills, Giovanni Baccolo, and Geoffrey E. Millward
The Cryosphere, 15, 5151–5168, https://doi.org/10.5194/tc-15-5151-2021, https://doi.org/10.5194/tc-15-5151-2021, 2021
Short summary
Short summary
Our paper presents results of sample collection and subsequent geochemical analyses from the glaciated Isfallsglaciären catchment in Arctic Sweden. The data suggest that material found on the surface of glaciers,
cryoconite, is very efficient at accumulating products of nuclear fallout transported in the atmosphere following events such as the Chernobyl disaster. We investigate how this compares with samples in the downstream environment and consider potential environmental implications.
Laura Summerauer, Philipp Baumann, Leonardo Ramirez-Lopez, Matti Barthel, Marijn Bauters, Benjamin Bukombe, Mario Reichenbach, Pascal Boeckx, Elizabeth Kearsley, Kristof Van Oost, Bernard Vanlauwe, Dieudonné Chiragaga, Aimé Bisimwa Heri-Kazi, Pieter Moonen, Andrew Sila, Keith Shepherd, Basile Bazirake Mujinya, Eric Van Ranst, Geert Baert, Sebastian Doetterl, and Johan Six
SOIL, 7, 693–715, https://doi.org/10.5194/soil-7-693-2021, https://doi.org/10.5194/soil-7-693-2021, 2021
Short summary
Short summary
We present a soil mid-infrared library with over 1800 samples from central Africa in order to facilitate soil analyses of this highly understudied yet critical area. Together with an existing continental library, we demonstrate a regional analysis and geographical extrapolation to predict total carbon and nitrogen. Our results show accurate predictions and highlight the value that the data contribute to existing libraries. Our library is openly available for public use and for expansion.
Heleen Deroo, Masuda Akter, Samuel Bodé, Orly Mendoza, Haichao Li, Pascal Boeckx, and Steven Sleutel
Biogeosciences, 18, 5035–5051, https://doi.org/10.5194/bg-18-5035-2021, https://doi.org/10.5194/bg-18-5035-2021, 2021
Short summary
Short summary
We assessed if and how incorporation of exogenous organic carbon (OC) such as straw could affect decomposition of native soil organic carbon (SOC) under different irrigation regimes. Addition of exogenous OC promoted dissolution of native SOC, partly because of increased Fe reduction, leading to more net release of Fe-bound SOC. Yet, there was no proportionate priming of SOC-derived DOC mineralisation. Water-saving irrigation can retard both priming of SOC dissolution and mineralisation.
Sebastian Doetterl, Rodrigue K. Asifiwe, Geert Baert, Fernando Bamba, Marijn Bauters, Pascal Boeckx, Benjamin Bukombe, Georg Cadisch, Matthew Cooper, Landry N. Cizungu, Alison Hoyt, Clovis Kabaseke, Karsten Kalbitz, Laurent Kidinda, Annina Maier, Moritz Mainka, Julia Mayrock, Daniel Muhindo, Basile B. Mujinya, Serge M. Mukotanyi, Leon Nabahungu, Mario Reichenbach, Boris Rewald, Johan Six, Anna Stegmann, Laura Summerauer, Robin Unseld, Bernard Vanlauwe, Kristof Van Oost, Kris Verheyen, Cordula Vogel, Florian Wilken, and Peter Fiener
Earth Syst. Sci. Data, 13, 4133–4153, https://doi.org/10.5194/essd-13-4133-2021, https://doi.org/10.5194/essd-13-4133-2021, 2021
Short summary
Short summary
The African Tropics are hotspots of modern-day land use change and are of great relevance for the global carbon cycle. Here, we present data collected as part of the DFG-funded project TropSOC along topographic, land use, and geochemical gradients in the eastern Congo Basin and the Albertine Rift. Our database contains spatial and temporal data on soil, vegetation, environmental properties, and land management collected from 136 pristine tropical forest and cropland plots between 2017 and 2020.
Simon Baumgartner, Marijn Bauters, Matti Barthel, Travis W. Drake, Landry C. Ntaboba, Basile M. Bazirake, Johan Six, Pascal Boeckx, and Kristof Van Oost
SOIL, 7, 83–94, https://doi.org/10.5194/soil-7-83-2021, https://doi.org/10.5194/soil-7-83-2021, 2021
Short summary
Short summary
We compared stable isotope signatures of soil profiles in different forest ecosystems within the Congo Basin to assess ecosystem-level differences in N cycling, and we examined the local effect of topography on the isotopic signature of soil N. Soil δ15N profiles indicated that the N cycling in in the montane forest is more closed, whereas the lowland forest and Miombo woodland experienced a more open N cycle. Topography only alters soil δ15N values in forests with high erosional forces.
Paula Alejandra Lamprea Pineda, Marijn Bauters, Hans Verbeeck, Selene Baez, Matti Barthel, Samuel Bodé, and Pascal Boeckx
Biogeosciences, 18, 413–421, https://doi.org/10.5194/bg-18-413-2021, https://doi.org/10.5194/bg-18-413-2021, 2021
Short summary
Short summary
Tropical forest soils are an important source and sink of greenhouse gases (GHGs) with tropical montane forests having been poorly studied. In this pilot study, we explored soil fluxes of CO2, CH4, and N2O in an Ecuadorian neotropical montane forest, where a net consumption of N2O at higher altitudes was observed. Our results highlight the importance of short-term variations in N2O and provide arguments and insights for future, more detailed studies on GHG fluxes from montane forest soils.
Simon Baumgartner, Matti Barthel, Travis William Drake, Marijn Bauters, Isaac Ahanamungu Makelele, John Kalume Mugula, Laura Summerauer, Nora Gallarotti, Landry Cizungu Ntaboba, Kristof Van Oost, Pascal Boeckx, Sebastian Doetterl, Roland Anton Werner, and Johan Six
Biogeosciences, 17, 6207–6218, https://doi.org/10.5194/bg-17-6207-2020, https://doi.org/10.5194/bg-17-6207-2020, 2020
Short summary
Short summary
Soil respiration is an important carbon flux and key process determining the net ecosystem production of terrestrial ecosystems. The Congo Basin lacks studies quantifying carbon fluxes. We measured soil CO2 fluxes from different forest types in the Congo Basin and were able to show that, even though soil CO2 fluxes are similarly high in lowland and montane forests, the drivers were different: soil moisture in montane forests and C availability in the lowland forests.
Loes G. J. van Bree, Francien Peterse, Allix J. Baxter, Wannes De Crop, Sigrid van Grinsven, Laura Villanueva, Dirk Verschuren, and Jaap S. Sinninghe Damsté
Biogeosciences, 17, 5443–5463, https://doi.org/10.5194/bg-17-5443-2020, https://doi.org/10.5194/bg-17-5443-2020, 2020
Short summary
Short summary
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are used as a paleothermometer based on their temperature dependence in global soils, but aquatic production complicates their use in lakes. BrGDGTs in the water column of Lake Chala, East Africa, respond to oxygen conditions and mixing. Changes in their signal can be linked to bacterial community composition rather than membrane adaptation to changing conditions. Their integrated signal in the sediment reflects mean air temperature.
Hannes P. T. De Deurwaerder, Marco D. Visser, Matteo Detto, Pascal Boeckx, Félicien Meunier, Kathrin Kuehnhammer, Ruth-Kristina Magh, John D. Marshall, Lixin Wang, Liangju Zhao, and Hans Verbeeck
Biogeosciences, 17, 4853–4870, https://doi.org/10.5194/bg-17-4853-2020, https://doi.org/10.5194/bg-17-4853-2020, 2020
Short summary
Short summary
The depths at which plants take up water is challenging to observe directly. To do so, scientists have relied on measuring the isotopic composition of xylem water as this provides information on the water’s source. Our work shows that this isotopic composition changes throughout the day, which complicates the interpretation of the water’s source and has been currently overlooked. We build a model to help understand the origin of these composition changes and their consequences for science.
Long Ho, Ruben Jerves-Cobo, Matti Barthel, Johan Six, Samuel Bode, Pascal Boeckx, and Peter Goethals
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-311, https://doi.org/10.5194/bg-2020-311, 2020
Revised manuscript not accepted
Short summary
Short summary
Rivers are being polluted by human activities, especially in urban areas. We studied the greenhouse gas (GHG) emissions from an urban river system. The results showed a clear trend between water quality and GHG emissions in which the more polluted the sites were, the higher were their emissions. When river water quality worsened, its contribution to global warming can go up by 10 times. Urban rivers emitted 4-times more than of the amount of GHGs compared to rivers in natural sites.
Marco Pfeiffer, José Padarian, Rodrigo Osorio, Nelson Bustamante, Guillermo Federico Olmedo, Mario Guevara, Felipe Aburto, Francisco Albornoz, Monica Antilén, Elías Araya, Eduardo Arellano, Maialen Barret, Juan Barrera, Pascal Boeckx, Margarita Briceño, Sally Bunning, Lea Cabrol, Manuel Casanova, Pablo Cornejo, Fabio Corradini, Gustavo Curaqueo, Sebastian Doetterl, Paola Duran, Mauricio Escudey, Angelina Espinoza, Samuel Francke, Juan Pablo Fuentes, Marcel Fuentes, Gonzalo Gajardo, Rafael García, Audrey Gallaud, Mauricio Galleguillos, Andrés Gomez, Marcela Hidalgo, Jorge Ivelic-Sáez, Lwando Mashalaba, Francisco Matus, Francisco Meza, Maria de la Luz Mora, Jorge Mora, Cristina Muñoz, Pablo Norambuena, Carolina Olivera, Carlos Ovalle, Marcelo Panichini, Aníbal Pauchard, Jorge F. Pérez-Quezada, Sergio Radic, José Ramirez, Nicolás Riveras, Germán Ruiz, Osvaldo Salazar, Iván Salgado, Oscar Seguel, Maria Sepúlveda, Carlos Sierra, Yasna Tapia, Francisco Tapia, Balfredo Toledo, José Miguel Torrico, Susana Valle, Ronald Vargas, Michael Wolff, and Erick Zagal
Earth Syst. Sci. Data, 12, 457–468, https://doi.org/10.5194/essd-12-457-2020, https://doi.org/10.5194/essd-12-457-2020, 2020
Short summary
Short summary
The CHLSOC database is the biggest soil organic carbon (SOC) database that has been compiled for Chile yet, comprising 13 612 data points. This database is the product of the compilation of numerous sources including unpublished and difficult-to-access data, allowing us to fill numerous spatial gaps where no SOC estimates were publicly available before. The values of SOC compiled in CHLSOC have a wide range, reflecting the variety of ecosystems that exists in Chile.
Natalie Orlowski, Lutz Breuer, Nicolas Angeli, Pascal Boeckx, Christophe Brumbt, Craig S. Cook, Maren Dubbert, Jens Dyckmans, Barbora Gallagher, Benjamin Gralher, Barbara Herbstritt, Pedro Hervé-Fernández, Christophe Hissler, Paul Koeniger, Arnaud Legout, Chandelle Joan Macdonald, Carlos Oyarzún, Regine Redelstein, Christof Seidler, Rolf Siegwolf, Christine Stumpp, Simon Thomsen, Markus Weiler, Christiane Werner, and Jeffrey J. McDonnell
Hydrol. Earth Syst. Sci., 22, 3619–3637, https://doi.org/10.5194/hess-22-3619-2018, https://doi.org/10.5194/hess-22-3619-2018, 2018
Short summary
Short summary
To extract water from soils for isotopic analysis, cryogenic water extraction is the most widely used removal technique. This work presents results from a worldwide laboratory intercomparison test of cryogenic extraction systems. Our results showed large differences in retrieved isotopic signatures among participating laboratories linked to interactions between soil type and properties, system setup, extraction efficiency, extraction system leaks, and each lab’s internal accuracy.
Marijn Bauters, Hans Verbeeck, Miro Demol, Stijn Bruneel, Cys Taveirne, Dries Van der Heyden, Landry Cizungu, and Pascal Boeckx
Biogeosciences, 14, 5313–5321, https://doi.org/10.5194/bg-14-5313-2017, https://doi.org/10.5194/bg-14-5313-2017, 2017
Short summary
Short summary
We assessed community-weighted functional canopy traits and indicative δ15N shifts along two new altitudinal transects in the tropical forest biome of both South America and Africa. We found that the functional forest composition and δ15N response along both transects was parallel, with a species shift towards more nitrogen-conservative species at higher elevations.
Dane Dickinson, Samuel Bodé, and Pascal Boeckx
Atmos. Meas. Tech., 10, 4507–4519, https://doi.org/10.5194/amt-10-4507-2017, https://doi.org/10.5194/amt-10-4507-2017, 2017
Short summary
Short summary
Cavity ring-down spectroscopy (CRDS) is an increasingly popular technology for isotope analysis of trace gases. However, most commercial CRDS instruments are designed for continuous gas sampling and cannot reliably measure small discrete samples. We present a novel technical adaptation that allows routine analysis of 50 mL syringed samples on an isotopic-CO2 CRDS unit. Our method offers excellent accuracy and precision, fast sample throughput, and is easily implemented in other CRDS instruments.
Louise C. Andresen, Anna-Karin Björsne, Samuel Bodé, Leif Klemedtsson, Pascal Boeckx, and Tobias Rütting
SOIL, 2, 433–442, https://doi.org/10.5194/soil-2-433-2016, https://doi.org/10.5194/soil-2-433-2016, 2016
Short summary
Short summary
In soil the constant transport of nitrogen (N) containing compounds from soil organic matter and debris out into the soil water, is controlled by soil microbes and enzymes that literally cut down polymers (such as proteins) into single amino acids (AA), hereafter microbes consume AAs and excrete ammonium back to the soil. We developed a method for analysing N turnover and flow of organic N, based on parallel 15N tracing experiments. The numerical model gives robust and simultaneous quantification.
François Klein, Hugues Goosse, Nicholas E. Graham, and Dirk Verschuren
Clim. Past, 12, 1499–1518, https://doi.org/10.5194/cp-12-1499-2016, https://doi.org/10.5194/cp-12-1499-2016, 2016
Short summary
Short summary
This paper analyses global climate model simulations of long-term East African hydroclimate changes relative to proxy-based reconstructions over the last millennium. No common signal is found between model results and reconstructions as well as among the model time series, which suggests that simulated hydroclimate is mostly driven by internal variability rather than by common external forcing.
Laura K. Buckles, Dirk Verschuren, Johan W. H. Weijers, Christine Cocquyt, Maarten Blaauw, and Jaap S. Sinninghe Damsté
Clim. Past, 12, 1243–1262, https://doi.org/10.5194/cp-12-1243-2016, https://doi.org/10.5194/cp-12-1243-2016, 2016
Short summary
Short summary
This paper discusses the underlying mechanisms of a method that uses specific membrane lipids present in the sediments of an African tropical lake to determine past changes in rainfall. With this method, past dry periods in the last 25 000 years can be assessed.
L. C. Andresen, S. Bode, A. Tietema, P. Boeckx, and T. Rütting
SOIL, 1, 341–349, https://doi.org/10.5194/soil-1-341-2015, https://doi.org/10.5194/soil-1-341-2015, 2015
J. W. van Groenigen, D. Huygens, P. Boeckx, Th. W. Kuyper, I. M. Lubbers, T. Rütting, and P. M. Groffman
SOIL, 1, 235–256, https://doi.org/10.5194/soil-1-235-2015, https://doi.org/10.5194/soil-1-235-2015, 2015
S. Doetterl, J.-T. Cornelis, J. Six, S. Bodé, S. Opfergelt, P. Boeckx, and K. Van Oost
Biogeosciences, 12, 1357–1371, https://doi.org/10.5194/bg-12-1357-2015, https://doi.org/10.5194/bg-12-1357-2015, 2015
Short summary
Short summary
We link the mineralogy of soils affected by erosion and deposition to the distribution of soil carbon fractions, their turnover and microbial activity. We show that the weathering status of soils and their history are controlling the stabilization of carbon with minerals. After burial, aggregated C is preserved more efficiently while non-aggregated C can be released and younger C re-sequestered more easily. Weathering changes the effectiveness of stabilization mechanism limiting this C sink.
I. Ssemmanda, V. Gelorini, and D. Verschuren
Clim. Past, 10, 2067–2080, https://doi.org/10.5194/cp-10-2067-2014, https://doi.org/10.5194/cp-10-2067-2014, 2014
Short summary
Short summary
Using fossil pollen assemblages to trace vegetation response to relatively modest historical climate fluctuations is difficult. In this study, pollen data from a lake-sediment record in Queen Elizabeth National Park (Uganda) show that its landscape has been an open wooded savannah throughout the past 200 years, with known historical moisture-balance variation exerting modest effects on local tree cover (mostly Acacia and Ficus) and the occurrence of damp soil areas (promoting Phoenix palms).
D. Xue, P. Boeckx, and Z. Wang
Biogeosciences, 11, 5957–5967, https://doi.org/10.5194/bg-11-5957-2014, https://doi.org/10.5194/bg-11-5957-2014, 2014
R. M. Rees, J. Augustin, G. Alberti, B. C. Ball, P. Boeckx, A. Cantarel, S. Castaldi, N. Chirinda, B. Chojnicki, M. Giebels, H. Gordon, B. Grosz, L. Horvath, R. Juszczak, Å. Kasimir Klemedtsson, L. Klemedtsson, S. Medinets, A. Machon, F. Mapanda, J. Nyamangara, J. E. Olesen, D. S. Reay, L. Sanchez, A. Sanz Cobena, K. A. Smith, A. Sowerby, M. Sommer, J. F. Soussana, M. Stenberg, C. F. E. Topp, O. van Cleemput, A. Vallejo, C. A. Watson, and M. Wuta
Biogeosciences, 10, 2671–2682, https://doi.org/10.5194/bg-10-2671-2013, https://doi.org/10.5194/bg-10-2671-2013, 2013
N. Gharahi Ghehi, C. Werner, K. Hufkens, R. Kiese, E. Van Ranst, D. Nsabimana, G. Wallin, L. Klemedtsson, K. Butterbach-Bahl, and P. Boeckx
Biogeosciences Discuss., https://doi.org/10.5194/bgd-10-1483-2013, https://doi.org/10.5194/bgd-10-1483-2013, 2013
Revised manuscript not accepted
Related subject area
Biogeochemistry: Stable Isotopes & Other Tracers
Fungi present distinguishable isotopic signals in their lipids when grown on glycolytic versus tricarboxylic acid cycle intermediates
Sea ice and mixed layer depth influence on nitrate depletion and associated isotopic effects in the Drake Passage–Weddell Sea region, Southern Ocean
Hydrodynamic and Primary Production Effects on Seasonal DO Variability in the Danube River
Stable iron isotope signals indicate a “pseudo-abiotic” process driving deep iron release in methanic sediments
Triple oxygen isotope evidence for the pathway of nitrous oxide production in a forested soil with increased emission on rainy days
Variability in oxygen isotopic fractionation of enzymatic O2 consumption
Previous integrated or organic farming affects productivity and ecosystem N balance rather than fertilizer 15N allocation to plants and soil, leaching, or gaseous emissions (NH3, N2O, and N2)
How long does carbon stay in a near-pristine central Amazon forest? An empirical estimate with radiocarbon
No increase is detected and modeled for the seasonal cycle amplitude of δ13C of atmospheric carbon dioxide
Bias in calculating gross nitrification rates in forested catchments using the triple oxygen isotopic composition (Δ17O) of stream nitrate
Position-specific kinetic isotope effects for nitrous oxide: a new expansion of the Rayleigh model
Technical note: A Bayesian mixing model to unravel isotopic data and quantify trace gas production and consumption pathways for time series data – Time-resolved FRactionation And Mixing Evaluation (TimeFRAME)
Separating above-canopy CO2 and O2 measurements into their atmospheric and biospheric signatures
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
Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies
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
Stanislav Jabinski, Vítězslav Kučera, Marek Kopáček, Jan Jansa, and Travis B. Meador
Biogeosciences, 22, 3127–3141, https://doi.org/10.5194/bg-22-3127-2025, https://doi.org/10.5194/bg-22-3127-2025, 2025
Short summary
Short summary
Microbial production is a key parameter in estimation of organic matter cycling in environmental systems, and fungi play a major role as decomposers. In order to improve investigation of fungal production and turnover times in environmental studies, we determined the isotopic signals encoded into lipid biomarkers of fungal pure cultures growing on various carbon substrates in media with isotopically labeled water and bicarbonate.
Aymeric P. M. Servettaz, Yuta Isaji, Chisato Yoshikawa, Yanghee Jang, Boo-Keun Khim, Yeongjun Ryu, Daniel M. Sigman, Nanako O. Ogawa, Francisco J. Jiménez-Espejo, and Naohiko Ohkouchi
Biogeosciences, 22, 2239–2260, https://doi.org/10.5194/bg-22-2239-2025, https://doi.org/10.5194/bg-22-2239-2025, 2025
Short summary
Short summary
Phytoplankton blooms occur after sea ice retreats in the Southern Ocean. In this study we investigate the influence of seasonal cycle of sea ice concentration on nitrate depletion, testing the hypothesis that meltwater release stabilizes the water column and favors nutrient utilization. We find that, at a regional scale, nitrate depletion and vertical mixing are weakly correlated with sea ice cycle. Nitrate depletion is rather linked to other oceanographic processes controlling mixing depth.
Jan Maier, Anna-Neva Visser, Christina Martina Schubert, Simon Thomas Wander, and Johannes Arthur Barth
EGUsphere, https://doi.org/10.5194/egusphere-2025-1580, https://doi.org/10.5194/egusphere-2025-1580, 2025
Short summary
Short summary
We present the first large-scale assessment of the dissolved oxygen (DO) budget and δ18ODO across the Danube to distinguish DO sources and sinks, key for biogeochemical cycles. Two highly productive areas in the warm season showed large deviations (+12.1 ‰) from atmospheric equilibrium (+24.6 ‰ ± 0.4 ‰), unusual for large rivers. Critically low DO in the Sava (0.16 mmol/L) and lower Danube (0.2 mmol/L) in late summer resulted from intensified respiration.
Susann Henkel, Bo Liu, Michael Staubwasser, Simone A. Kasemann, Anette Meixner, David A. Aromokeye, Michael W. Friedrich, and Sabine Kasten
Biogeosciences, 22, 1673–1696, https://doi.org/10.5194/bg-22-1673-2025, https://doi.org/10.5194/bg-22-1673-2025, 2025
Short summary
Short summary
We intend to unravel iron (Fe) reduction pathways in high-deposition methanic sediments because pools of Fe minerals could stimulate methane oxidation and also generation. Our data from the North Sea show that Fe release takes place mechanistically differently to Fe reduction in shallow sediments, which typically fractionates Fe isotopes. We conclude that fermentation of organic matter involving interspecies electron transfer, partly through conductive Fe oxides, could play an important role.
Weitian Ding, Urumu Tsunogai, Tianzheng Huang, Takashi Sambuichi, Wenhua Ruan, Masanori Ito, Hao Xu, Yongwon Kim, and Fumiko Nakagawa
EGUsphere, https://doi.org/10.21203/rs.3.rs-4264720/v2, https://doi.org/10.21203/rs.3.rs-4264720/v2, 2025
Short summary
Short summary
Identifying the pathways of N2O produced through nitrification and denitrification in soil is crucial for effective mitigation. Thus, we monitored a new natural isotopic signature (Δ17O) of N2O in forested soil for identifying the pathways, which is almost stable during various biogeochemical processes. Our results suggest Δ17O is a promising signature for identifying pathways of N2O production, revealing that increased denitrification drives the high emission of N2O in soil on rainy days.
Carolina F.M. de Carvalho, Moritz F. Lehmann, and Sarah G. Pati
EGUsphere, https://doi.org/10.5194/egusphere-2025-1193, https://doi.org/10.5194/egusphere-2025-1193, 2025
Short summary
Short summary
Using O2 stable isotope analysis, we determined the isotopic fractionation of biological O2 consumption by 10 flavin-dependent and 6 metalloenzymes. Metalloenzymes displayed a narrower range and lower values of isotopic fractionation than flavin-dependent enzymes. This work expands our understanding of the variability of oxygen isotopic fractionation at the enzyme level, improving the ability to study O2 dynamics from molecular to ecosystem scales.
Fawad Khan, Samuel Franco Luesma, Frederik Hartmann, Michael Dannenmann, Rainer Gasche, Clemens Scheer, Andreas Gattinger, Wiebke Niether, Elizabeth Gachibu Wangari, Ricky Mwangada Mwanake, Ralf Kiese, and Benjamin Wolf
EGUsphere, https://doi.org/10.5194/egusphere-2025-292, https://doi.org/10.5194/egusphere-2025-292, 2025
Short summary
Short summary
Crop rotations with legumes and use of organic and mineral fertilizers show potential to reduce agricultural N losses. This study examined N losses, including direct N2 flux, on two adjacent sites with different management history: organic farming (OF) with legume cultivation and integrated farming (IF) using synthetic and organic N inputs. IF increased soil organic carbon and nitrogen content, 15N recovery and showed a balanced N budget, i.e., more efficient N cycling compared to OF.
Ingrid Chanca, Ingeborg Levin, Susan Trumbore, Kita Macario, Jost Lavric, Carlos Alberto Quesada, Alessandro Carioca de Araújo, Cléo Quaresma Dias Júnior, Hella van Asperen, Samuel Hammer, and Carlos A. Sierra
Biogeosciences, 22, 455–472, https://doi.org/10.5194/bg-22-455-2025, https://doi.org/10.5194/bg-22-455-2025, 2025
Short summary
Short summary
Assessing the net carbon (C) budget of the Amazon entails considering the magnitude and timing of C absorption and losses through respiration (transit time of C). Radiocarbon-based estimates of the transit time of C in the Amazon Tall Tower Observatory (ATTO) suggest a change in the transit time from 6 ± 2 years and 18 ± 4 years within 2 years (October 2019 and December 2021, respectively). This variability indicates that only a fraction of newly fixed C can be stored for decades or longer.
Fortunat Joos, Sebastian Lienert, and Sönke Zaehle
Biogeosciences, 22, 19–39, https://doi.org/10.5194/bg-22-19-2025, https://doi.org/10.5194/bg-22-19-2025, 2025
Short summary
Short summary
How plants regulate their exchange of CO2 and water with the atmosphere under global warming is critical for their carbon uptake and their cooling influence. We analyze the isotope ratio of atmospheric CO2 and detect no significant decadal trends in the seasonal cycle amplitude. The data are consistent with the regulation towards leaf CO2 and intrinsic water use efficiency growing proportionally to atmospheric CO2, in contrast to recent suggestions of downregulation of CO2 and water fluxes.
Weitian Ding, Urumu Tsunogai, and Fumiko Nakagawa
Biogeosciences, 21, 4717–4722, https://doi.org/10.5194/bg-21-4717-2024, https://doi.org/10.5194/bg-21-4717-2024, 2024
Short summary
Short summary
Past studies have used the Δ17O of stream nitrate to estimate the gross nitrification rates (GNRs) in each forested catchment by approximating the Δ17O value of soil nitrate to be equal to that of stream nitrate. Based on inference and calculation of measured data, we found that this approximation resulted in an overestimated GNR. Therefore, it is essential to clarify and verify the Δ17O NO3− values in forested soils and streams before applying the Δ17O values of stream NO3− to GNR estimation.
Elise D. Rivett, Wenjuan Ma, Nathaniel E. Ostrom, and Eric L. Hegg
Biogeosciences, 21, 4549–4567, https://doi.org/10.5194/bg-21-4549-2024, https://doi.org/10.5194/bg-21-4549-2024, 2024
Short summary
Short summary
Many different processes produce nitrous oxide (N2O), a potent greenhouse gas. Measuring the ratio of heavy and light nitrogen isotopes (15N/14N) for the non-exchangeable central and outer N atoms of N2O helps to distinguish sources of N2O. To accurately calculate the position-specific isotopic preference, we developed an expansion of the widely used Rayleigh model. Application of our new model to simulated and experimental data demonstrates its improved accuracy for analyzing N2O synthesis.
Eliza Harris, Philipp Fischer, Maciej P. Lewicki, Dominika Lewicka-Szczebak, Stephen J. Harris, and Fernando Perez-Cruz
Biogeosciences, 21, 3641–3663, https://doi.org/10.5194/bg-21-3641-2024, https://doi.org/10.5194/bg-21-3641-2024, 2024
Short summary
Short summary
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
Short summary
Short summary
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
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.
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
Short summary
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.
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.
Cited articles
Araguás-Araguás, L., Rozanski, K., Gonfiantini, R., and Louvat, D.: Isotope effects accompanying vacuum extraction of soil water for stable isotope analyses, J. Hydrol., 168, 159–171, 1995.
Araguás-Araguás, L., Froehlich, K., and Rozanski, K.: Deuterium and oxygen-18 isotope composition of precipitation and atmospheric moisture, Hydrol. Process., 14, 1341–1355, 2000.
Barker, P. A., Hurell, E. R., Leng, M. J.,Wolff, C., Cocquyt, C., Sloane, H. J., and Verschuren, D.: Seasonality in equatorial climate over the past 25 kyr−1 revealed by oxygen isotope records from Mount Kilimanjaro, Geology, 39, 1111–1114, 2011.
Breitenbach, S., Adkins, J., Meyer, H., Marwan, N., Kumar, K., and Haug, G.: Strong influence of water vapor source dynamics on stable isotopes in precipitation observed in Southern Meghalaya, NE India, Earth Planet. Sc. Lett., 292, 212–220, 2010.
Brooks, J., Barnard, H., Coulombe, R., and Mcdonnell, J.: Ecohydrologic separation of water between trees and streams in a Mediterranean climate, Nat. Geosci., 3, 100–104, 2010.
Buckles, L. K., Weijers, J. W. H., Verschuren, D., and Sinninghe Damsté, J. S.: Sources of core and intact branched tetraether membrane lipids in the lacustrine environment: anatomy of Lake Challa and its catchment, equatorial East Africa, Geochim. Cosmochim. Ac., 140, 106–126, 2014.
Burghardt, M. and Riederer, M.: Ecophysiological relevance of cuticular transpiration of deciduous and evergreen plants in relation to stomatal closure and leaf water potential, J. Exp. Bot., 54, 1941–1949, https://doi.org/10.1093/jxb/erg195, 2003.
Caldwell, M. M., Dawson, T. E., and Richards, J. H.: Hydraulic lift: consequences of water efflux from roots of plants, Oecologia, 113, 151–161, 1998.
Cernusak, L. A., Pate, J. S., and Farquhar, G. D.: Diurnal variation in the stable isotope composition of water and dry matter in fruiting Lupinus angustifolius under field conditions, Plant Cell Environ., 25, 893–907, 2002.
Chabot, B. F. and Hicks, D. J.: The ecology of leaf life spans, Annu. Rev. Ecol. Syst., 13, 229–259, 1982.
Cohen, E. R., Cvitas, T., Frey, J. G., Holmstrom, B., Kuchitsu, K., Marquardt, R., Mills, I., Pavese, F., Quack, M., Stohner, J., Strauss, H. L., Takami, M., and Thor, A. J.: Quantities, Units and Symbols in Physical Chemistry, Cambridge, UK, R. Soc. Chem. Publ. 265 pp. 3rd ed., 2007.
Corbin, J. D., Thomsen, M. A., Dawson, T. E., and D'Antonio, C. M.: Summer water use by California coastal prairie grasses: fog, drought, and community composition, Oecologia, 145, 511–521, 2005.
Costa, K., Russell, J., Konecky, B., and Lamb, H.: Isotopic reconstruction of the African Humid Period and Congo Air Boundary migration at Lake Tana, Ethiopia, Quaternary Sci. Rev., 83, 58–67, 2014.
Craig, H.: Isotopic variations in meteoric waters, Science, 133, 1702–1703, 1961.
Craig, H. and Gordon, L. I.: Deuterium and oxygen-18 variations in the ocean and the marine atmosphere, in: Proceedings of the conference on stable isotopes in oceanographic studies and paleotemperatures, edited by: Tongiorgi, E., Laboratory of Geology and Nuclear Science, Pisa, Italy, 9–130, 1965.
Dansgaard, W.: Stable isotopes in precipitation, Tellus, 16, 436–468, 1964.
Dawson, T. and Ehleringer, J.: Streamside trees that do not use stream water, Nature, 350, 335–337, 1991.
Dawson, T. and Ehleringer, J.: Isotopic enrichment of water in the “woody” tissues: Implications for plant water source, water uptake, and other studies which use the stable isotopic composition of cellulose, Geochim. Cosmochim Ac., 57, 3487–3492, 1993.
Dawson, T. E.: Determining water use by trees and forests from isotopic, energy balance and transpiration analyses: the roles of tree size and hydraulic lift, Tree Physiol., 16, 263–272, 1996.
De Wispelaere, L., Bodé, S., Hervé-Fernández, P., Hemp, A., Verschuren, D., and Boeckx, P.: Lake Challa Savannah data, available at: http://apps.neotomadb.org/Explorer/?datasetid=21119, last access: 5 January 2017.
De Wispelaere, L., Bodé, S., Hervé-Fernández, P., Hemp, A., Verschuren, D., and Boeckx, P.: Lake Challa Lakeshore data, available at: http://apps.neotomadb.org/Explorer/?datasetid=21147, last access: 5 January 2017.
De Wispelaere, L., Bodé, S., Hervé-Fernández, P., Hemp, A., Verschuren, D., and Boeckx, P.: Lake Challa Crater Rim data, available at: http://apps.neotomadb.org/Explorer/?datasetid=21148, last access: 5 January 2017.
Draxler, R. and Hess, G. D.: Description of the HYSPLIT_4 modeling system, NOAA Technical Memorandum ERL ARL-224, NOAA Air Resources Laboratory, Silver Spring, Maryland, USA, 2004.
Duff, G. A., Myers, B. A., Williams, R. J., Eamus, D., O'Grady, A., and Fordyce, I. R.: Seasonal patterns in soil moisture, vapor pressure deficit, tree canopy cover and pre-dawn water potential in a northern Australian savanna, Aust. J. Bot., 45, 211–274, 1997.
Eglinton, G. and Hamilton, R. J.: Leaf epicuticular waxes, Science, 156, 1322–1335, 1967.
Ehleringer, J. R., Phillips, S. L., Schuster, W. F. S., and Sandquist, D. R.: Differential utilization of summer rains by desert plants, Oecologia, 88, 430–434, 1991.
Elffers, J., Graham, A., and DeWolf, G. P.: Capparidaceae, in: Flora of tropical East Africa, edited by: Hubbard, C. E. and Milne-Redhead, E., 35, Crown Agents for Oversea Governments and Administrations, London, UK, 1964.
Ellsworth, P. and Williams, D.: Hydrogen isotope fractionation during water uptake by woody xerophytes, Plant Soil, 291, 93–107, 2007.
Evaristo, J., Jasenchko, S., and McDonnell, J. J.: Global separation of plant transpiration from groundwater and streamflow, Nature, 525, 91–97, 2015.
Farquhar, G. D., Cernusak, L. A., and Barnes, B.: Heavy water fractionation during transpiration, Plant Physiol., 143, 11–18, 2007.
Feakins, S. J. and Sessions, A. L.: Controls on the D/H ratios of plant leaf waxes from an arid ecosystem, Geochim. Cosmochim. Ac., 74, 2128–2141, 2010.
Field, T. S. and Dawson, T. E.: Water sources used by Didmopanax pittieri at different life stages in a tropical cloud forest, Ecology, 79, 1448–1452, 1998.
Friedman, I., Smith, G. I., Gleason, J. D., Warden, A., and Harris, J.: Stable isotope composition of waters in southeastern California, J. Geophys. Res., 97, 5795–5812, 1992.
Garcin, Y., Schwab, V. F., Gleixne, R. G., Kahmen, A., Todou, G., Sene, O., and Sachse, D.: Hydrogen isotope ratios of lacustrine sedimentary n-alkanes as proxies of tropical African hydrology: insights from a calibration transect across Cameroon, Geochim. Cosmochim. Ac., 79, 106–126, 2012.
Gat, J. R.: Oxygen and hydrogen isotopes in the hydrologic cycle, Annu. Rev. Earth Pl. Sc., 24, 225–262, 1996.
Gat, J.: Isotope Hydrology: A Study of the Water Cycle, Imperial College Press: 57 Shelton Street, Covent Garden, London, UK, 2005.
Gibson, J. J., Birks, S. J., and Edwards, T. W. D.: Global prediction of δA and δ2H-δ18O evaporation slopes for lakes and soil water accounting for seasonality, Global Biogeochem. Cy., 22, GB2031, https://doi.org/10.1029/2007GB002997, 2008.
Goldsmith, G., Muñoz-Villers, L., Holwerda, F., McDonnell, J., Asbjornsen, H., and Dawson, T.: Stable isotopes reveal linkages among ecohydrological processes in a seasonally dry tropical montane cloud forest, Ecohydrology, 5, 779–790, 2011.
Goldstein, G., Meinzer, F. C., Bucci, S. J., Scholz, F. G., Franco, A. C., and Hoffmann, W. A.: Water economy of Neotropical savanna trees: six paradigms revisited, Tree Physiol., 28, 395–404, 2008.
Groning, M., Lutz, H. O., Roller-Lutz, Z., Kralik, M., Gourcy, L., and Poltenstein, L.: A simple rain collector preventing water re-evaporation dedicated for δ18O and δ2H analysis of cumulative precipitation samples, J. Hydrol., 448–449, 195–200, 2012.
Hastilestari, B. R., Mudersbach, M., Tomala, F., Vogt, H., Biskupek-Korell, B., Van Damme, P., Guretzki, S., and Papenbrock, J.: Euphorbia tirucalli L. – Comprehensive Characterization of a Drought Tolerant Plant with a Potential as Biofuel Source, PLoS ONE, 8, e63501, https://doi.org/10.1371/journal.pone.0063501, 2013.
Helliker, B. R. and Ehleringer, J. R.: Establishing a grassland signature in veins: 18O in the leaf water of C3 and C4 grasses, P. Natl. Acad. Sci. USA, 97, 7894–7898, 2000.
Hemp A.: Ecology of the pteridophytes on the southern slopes of Mt. Kilimanjaro, Part II: Habitat selection, Plant Biol., 3, 493–523, 2001.
Hemp, A.: Continuum or zonation? Altitudinal gradients in the forest vegetation of Mt. Kilimanjaro, Plant Ecol., 184, 27–42, 2006a.
Hemp, A.: Vegetation of Kilimanjaro: hidden endemics and missing bamboo, Afr. J. Ecol., 44, 305–328, 2006b.
Hou, J., D'Andrea, W. J., and Huang, Y.: Can sedimentary leaf waxes record D/H ratios of continental precipitation? Field, model, and experimental assessments, Geochim. Cosmochim. Ac., 72, 3503–3517, 2008.
Huang, Y., Shuman, B., Wang, Y., and Webb, I. I. I. T.: Hydrogen isotope ratios of individual lipids in lake sediments as novel tracers of climatic and environmental change: a surface sediment test, J. Paleolimnol., 31, 363–375, 2004.
Jackson, P. C., Cavelier, J., Goldstein, G., Meinzer, F. C., and Holbrook, N. M.: Partitioning of Water Resources among Plants of a Lowland Tropical Forest, Oecologia, 101, 197–203, 1995.
Jackson, P. C., Meinzer, F. C., Bustamante, M., Goldstein, G., Franco, A., Rundel, P. W., and Caldas, L.: Partitioning of soil among tree species in a Brazilian Cerrado ecosystem, Tree Physiol., 19, 717–724, 1999.
Kahmen, A., Simonin, K., Tu, K. P., Merchant, A., Callister, A., Siegwolf, R., Dawson, T. E., and Arndt, S. K.: Effects of environmental parameters, leaf physiological properties and leaf water relations on leaf water δ18O enrichment in different Eucalyptus species, Plant Cell Environ., 31, 738–751, https://doi.org/10.1111/j.1365-3040.2008.01784.x, 2008.
Kahmen, A., Hoffmann, B., Schefuss, E., Arndt, S. K., Cernusak, L. A., West, J. B., and Sachse, D.: Leaf water deuterium enrichment shapes leaf wax n-alkane delta D values of angiosperm plants II: Observational evidence and global implications, Geochim. Cosmochim. Ac., 111, 50–63, 2013.
Kenya Food Security Group (KFSSG): October to December 2013 short rains season assessment report, Collaborative report of the Kenya Food Security Steering Group: Ministries of Devolution and Planning, Agriculture, Livestock and Fisheries, Environment, Water and Natural Resources, Health, and Education, Science and Technology, National Drought Management Authority, WFP/VAM, FEWS NET, FAO, CARE-Kenya, UNICEF, World Vision, ACF; with financial support from the Government of Kenya, FAO and WFP; February 2014.
Ladd, S. N. and Sachs, J. P.: Influence of salinity on hydrogen isotope fractionation in Rhizophora mangroves from Micronesia, Geochim. Cosmochim. Ac., 168, 206–221, 2015.
Li, S. G., Tsujimura, M., Sugimoto, A., Sasaki, L., Yamanaka, T., Davaa, G., Oyunbaatar, D., and Sugita, M.: Seasonal variation in oxygen isotope composition of water for a montane larch forest in Mongolia, Trees-Struct. Funct., 20, 122–130, 2006.
Liu, W. and Yang, H.: Multiple controls for the variability of hydrogen isotope compositions in higher plant n-alkanes from modern ecosystems, Global Change Biol., 14, 2166–2177, 2008.
Liu, W., Liu, W., Li, P., Duan, W., and Li, H.: Dry season water uptake by two dominant canopy tree species in a tropical seasonal rainforest of Xishuangbanna, SW China, Agr. Forest Meteorol., 150, 380–388, 2010.
Martín-Goméz, P., Barbeta, A., Voltas, J., Penuelas, J., Dennis, K., Palacio, S., Dawson, T., and Ferrio, J.: Methods Isotope-ratio infrared spectroscopy: a reliable tool for the investigation of plant-water sources?, New Phytol., 207, 914–927, 2015.
Mayer, B. and Schwark, L.: A 15 000-year stable isotope record from sediments of Lake Steisslingen, Southwest Germany, Chem. Geol., 161, 315–337, 1999.
McKenzie, J. M., Mark, B. G., Thompson, L. G., Schotterer U., and Lin, P.: A hydrogeochemical survey of Kilimanjaro (Tanzania): implication for water sources and ages, Hydrogeol. J., 18, 985–995, 2010.
Meinzer, F. C., Andrade, J. L., Goldstein, G., Holbrook, M. N., Cavelier, J., and Wright, S. J.: Partitioning of soil water among canopy trees in a seasonally dry tropical forest, Oecologia, 121, 293–301, 1999.
Meinzer, F. C., Goldstein, G., Holbrook, N. M., Jackson, P., and Cavelier, J.: Stomatal and environmental control of transpiration in a lowland tropical forest tree, Plant Cell Environ., 16, 429–436, 1993.
Moernaut, J., Verschuren, D., Charlet, F., Kristen, I., Fagot, M., and De Batist, M.: The seismic-stratigraphic record of lake-level fluctuations in Lake Challa: hydrological stability and change in equatorial East Africa over the last 140 kyr, Earth Planet. Sc. Lett., 290, 214–223, 2010.
Nicholson, S. E.: The nature of rainfall variability over Africa on time scales of decades to millennia, Global Planet Change, 26, 137–158, https://doi.org/10.1016/S0921-8181(00)00040-0, 2000.
O'Grady, A.P., Eamus, D., and Hutley, B.: Transpiration increases during the dry season: patterns of tree water use in eucalypt open-forests of northern Australia, Tree Physiol., 19, 591–597, 1999.
Oliveira, F. M., Meirelles, S. T., and Salatino, A.: Epicuticular waxes from caatinga and cerrado species and their efficiency against water loss, Annals of the Brazilian Academy of Sciences, 75, 432–439, 2003.
Orlowski, N., Pratt, D. L., and McDonnell, J. J.: Intercomparison of soil pore water extraction methods for stable isotope analysis, Hydrol. Process., 30, 3434–3449, https://doi.org/10.1002/hyp.10870, 2016
Payne, B. R.: Water balance of Lake Chala and its relation to groundwater from tritium and stable isotope data, J. Hydrol., 11, 47–58, 1970.
Polissar, P. J. and Freeman, K. H.: Effects of aridity and vegetation on plant-wax δ2H in modern lake sediments, Geochim. Cosmochim. Ac., 74, 5785–5797, 2010.
Prior, L. D., Eamus, D., and Duff, G. A.: Seasonal trends in carbon assimilation, stomatal conductance and pre-dawn leaf water potential in Terminialia ferdinandiana, a deciduous tree of northern Australian savannas, Aust. J. Bot., 45, 53–69, 1997.
Rozanski, K., Araguás-Araguás, L., and Gonfiantini, R.: Isotopic patterns in modern global precipitation, Geophysical Monograph, 78, 1–35, 1993.
Sachse, D., Radke, J., and Gleixner, G.: Hydrogen isotope ratios of recent lacustrine sedimentary n-alkane record modern climate variability, Geochim. Cosmochim. Ac., 63, 4877–4889, 2004.
Sachse, D., Billault, I., Bowen, G., Chikaraishi, Y., Dawson, T., Feakins, S. J., Freeman, K. H., Magill, C. R., McInerney, F. A., van der Meer, M. T. J., Polissar, P., Robins, R. J., Sachs, J. P., Schmidt, H., Sessions, A. L., White, J. W. C., West, J. B., and Kahmen, A.: Molecular Paleohydrology: Interpreting the Hydrogen-Isotopic Composition of Lipid Biomarkers from Photosynthesizing Organisms, Annu Rev. Earth Pl. Sc., 40, 221–249, 2012.
Schönherr, J.: Resistance of plant surfaces to water loss: transport properties of cutin, suberin and associated lipids, in: Encyclopedia of plant physiology, edited by: Lange, O. L., Nobel, P. S., Osmond, C. B., and Ziegler, H., Springer, Berlin, Germany, 12B, 153–179, 1982.
Sessions, A. L.: Seasonal changes in D/H fractionation accompanying lipid biosynthesis in Spartina alterniflora, Geochim. Cosmochim. Ac., 70, 2153–2162, 2006.
Sessions, A. L., Burgoyne, T. W., Schimmelmann, A., and Hayes, J. M.: Fractionation of hydrogen isotopes in lipid biosynthesis, Org. Geochem., 30, 1193–1200, 1999.
Smith, F. A. and Freeman, K. H.: Influence of physiology and climate on δ2H of leaf wax n-alkanes from C3 and C4 grasses, Geochim. Cosmochim. Ac., 70, 1172–1187, 2006.
Soderberg, K., Good, S. P., O'Conner, M., Wang, L., Ryan, K., and Caylor, K. K.: Using air parcel trajectories to model the isotopic composition of rainfall in central Kenya, Ecosphere, 4, 1–18, https://doi.org/10.1890/ES12-00160.1, 2013.
Stahl, C., Hérault, B., Rossi, V., Burban, B., Bréchet, C., and Bonal, D.: Depth of soil water uptake by tropical rainforest trees during dry periods: does tree dimension matter?, Oecologia, 173, 1191–1201, 2013.
Stratton, L. C., Goldstein, G., and Meinzer, F. C.: Temporal and spatial partitioning of water resources among eight woody species in a Hawaiian dry forest, Oecologia, 124, 309–317, 2000.
Tierney, J. E., Russell, J. M., Huang, Y., Sinninghe Damsté, J. S., Hopmans, E. C., and Cohen, A. S.: Northern hemisphere controls on tropical southeast African climate during the past 60 000 years, Science, 322, 252–254, 2008.
Tierney, J. E., Russell, J. M., Sinninghe Damsté, J. S., Huang, Y., and Verschuren, D.: Late Quaternary behavior of the East African monsoon and the importance of the Congo Air Boundary, Quaternary Sci. Rev., 30, 798–807, 2011.
Tipple, B. and Pagani, M.: Environmental control on eastern broadleaf forest species' leaf wax distributions and D/H ratios, Geochim. Cosmochim. Ac., 111, 64–77, 2013.
Thompson, L. G., Mosley-Thompson, E., Davis, M. E., Lin, P. N., Henderson, K., and Mashiotta, T. A.: Tropical glacier and ice core evidence of climate change on annual to millennial time scales, Climatic Change, 59, 137–155, 2003.
Van Damme, P.: Euphorbia tirucalli for High Biomass Production, in: Combating desertification with plants, Conferenc, 1–5 November 1999, Be'er Sheva, Israel, 1999.
Verschuren, D., Sinninghe Damsté, J. S., Moernaut, J., Kristen, I., Blaauw, M., Fagot, M., Haug, G. H., and CHALLACEA project members: Halfprecessional dynamics of monsoon rainfall near the East African Equator, Nature, 462, 637–641, 2009.
Volkens, G.: Der Kilimandscharo. Darstellung der allgemeineren Ergebnisse eines fünfzehnmonatigen Aufenthalts im Dschaggalande, Reimer, Berlin, Germany, 1897.
von Grafenstein, U., Erlenkeuser, H., Brauer, A., Jouzel, J., and Johnsen, S. J.: A mid-European decadal isotopeclimate record from 15 500 to 5000 years B.P., Science, 284, 1654–1657, 1999.
West, A. G., Patrickson, S. J., and Ehleringer, J. R.: Water extraction times for plant and soil materials used in stable isotope analysis, Rapid Commun. Mass Sp., 20, 1317–1321, 2006.
White, J. W. C., Cook, E. R., Lawrence, J. R., and Broecker, W. S.: The D/H ratios of sap in trees: Implications for water sources and tree ring D/H ratios, Geochim. Cosmochim. Ac., 49, 237–246, 1985.
Wolff, C., Kristen-Jenny, I., Schettler, G., Plessen, B., Meyer, H., Dulski, P., Naumann, R., Brauer, A., Verschuren, D., and Haug, G. H.: Modern seasonality in Lake Challa (Kenya/Tanzania) and its sedimentary documentation in recent lake sediments, Limnol. Oceanogr., 59, 1621–1636, 2014.
Zhao, L., Wang, L., Cernusak, L. A., Xiaohong, L., Xiao, H., Zhou, M., and Zhang, S.: Significant difference in hydrogen isotope composition between xylem and tissue water in Populus euphratica, Plant Cell Environ., 39, 1848–1857, https://doi.org/10.1111/pce.12753, 2016.
Zimmermann, U., Ehhalt, D., and Münnich, K.: Soil-Water movement and evapotranspration: changes in the isotopic composition of the water, in: Conference on Isotopes in Hydrology, 14–18 November 1966, Vienna, Austria, 567–585, 1967.
Zuber, A.: On the environmental isotope method for determining the water balance components of some lakes, J. Hydrol., 61, 409–427, 1983.
Altmetrics
Final-revised paper
Preprint