Articles | Volume 14, issue 4
https://doi.org/10.5194/bg-14-1021-2017
© 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-14-1021-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
03 Mar 2017
Research article |
| 03 Mar 2017
Quantification of multiple simultaneously occurring nitrogen flows in the euphotic ocean
Min Nina Xu
State Key Laboratory of Marine Environmental Science, Xiamen
University, Xiamen, China
Yanhua Wu
Shenzhen Marine Environment Monitoring Center Station, State Oceanic Administration, Shenzhen, China
Li Wei Zheng
State Key Laboratory of Marine Environmental Science, Xiamen
University, Xiamen, China
Zhenzhen Zheng
State Key Laboratory of Marine Environmental Science, Xiamen
University, Xiamen, China
Huade Zhao
National Marine Environmental Monitoring Center, Dalian, China
Edward A. Laws
Environmental Sciences Department, School of the Coast &
Environment, Louisiana State University, Baton Rouge, USA
Shuh-Ji Kao
CORRESPONDING AUTHOR
State Key Laboratory of Marine Environmental Science, Xiamen
University, Xiamen, China
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Earth Syst. Sci. Data, 15, 3673–3709, https://doi.org/10.5194/essd-15-3673-2023, https://doi.org/10.5194/essd-15-3673-2023, 2023
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N2 fixation by marine diazotrophs is an important bioavailable N source to the global ocean. This updated global oceanic diazotroph database increases the number of in situ measurements of N2 fixation rates, diazotrophic cell abundances, and nifH gene copy abundances by 184 %, 86 %, and 809 %, respectively. Using the updated database, the global marine N2 fixation rate is estimated at 223 ± 30 Tg N yr−1, which triplicates that using the original database.
Xiaofeng Dai, Mingming Chen, Xianhui Wan, Ehui Tan, Jialing Zeng, Nengwang Chen, Shuh-Ji Kao, and Yao Zhang
Biogeosciences, 19, 3757–3773, https://doi.org/10.5194/bg-19-3757-2022, https://doi.org/10.5194/bg-19-3757-2022, 2022
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This study revealed the distinct distribution patterns of six key microbial functional genes and transcripts related to N2O sources and sinks in four estuaries spanning the Chinese coastline, which were significantly constrained by nitrogen and oxygen concentrations, salinity, temperature, and pH. The community structure of the nosZ clade II was distinctly different from those in the soil and marine OMZs. Denitrification may principally control the N2O emissions patterns across the estuaries.
Siqi Wu, Moge Du, Xianhui Sean Wan, Corday Selden, Mar Benavides, Sophie Bonnet, Robert Hamersley, Carolin R. Löscher, Margaret R. Mulholland, Xiuli Yan, and Shuh-Ji Kao
Biogeosciences Discuss., https://doi.org/10.5194/bg-2021-104, https://doi.org/10.5194/bg-2021-104, 2021
Preprint withdrawn
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Nitrogen (N2) fixation is one of the most important nutrient sources to the ocean. Here, we report N2 fixation in the deep, dark ocean in the South China Sea via a highly sensitive new method and elaborate controls, showing the overlooked importance of N2 fixation in the deep ocean. By global data compilation, we also provide an easy measured basic parameter to estimate deep N2 fixation. Our study may help to expand the area limit of N2 fixation studies and better constrain global N2 fixation.
Yanhong Lu, Shunyan Cheung, Ling Chen, Shuh-Ji Kao, Xiaomin Xia, Jianping Gan, Minhan Dai, and Hongbin Liu
Biogeosciences, 17, 6017–6032, https://doi.org/10.5194/bg-17-6017-2020, https://doi.org/10.5194/bg-17-6017-2020, 2020
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Through a comprehensive investigation, we observed differential niche partitioning among diverse ammonia-oxidizing archaea (AOA) sublineages in a typical subtropical estuary. Distinct AOA communities observed at DNA and RNA levels suggested that a strong divergence in ammonia-oxidizing activity among different AOA groups occurs. Our result highlights the importance of identifying major ammonia oxidizers at RNA level in future studies.
Lei Hou, Xiabing Xie, Xianhui Wan, Shuh-Ji Kao, Nianzhi Jiao, and Yao Zhang
Biogeosciences, 15, 5169–5187, https://doi.org/10.5194/bg-15-5169-2018, https://doi.org/10.5194/bg-15-5169-2018, 2018
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The niche differentiation of ammonia and nitrite oxidizers is controversial because they display disparate patterns in different environments. Combining molecular and nitrification rate analyses, our study clarified that water mass mixing and the substrate availability primarily regulated the niche differentiation of nitrifier populations along a salinity gradient. The nitrifier populations may have specific adaptations to different substrate conditions through their ecological strategies.
Li Luo, Shuh-Ji Kao, Hongyan Bao, Huayun Xiao, Hongwei Xiao, Xiaohong Yao, Huiwang Gao, Jiawei Li, and Yangyang Lu
Atmos. Chem. Phys., 18, 6207–6222, https://doi.org/10.5194/acp-18-6207-2018, https://doi.org/10.5194/acp-18-6207-2018, 2018
Yangyang Lu, Zuozhu Wen, Dalin Shi, Mingming Chen, Yao Zhang, Sophie Bonnet, Yuhang Li, Jiwei Tian, and Shuh-Ji Kao
Biogeosciences, 15, 1–12, https://doi.org/10.5194/bg-15-1-2018, https://doi.org/10.5194/bg-15-1-2018, 2018
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We investigated the light response of field Trichodesmium N2 fixation and net dissolved nitrogen release behavior. Our results suggest that N2 fixation was a function of light intensity, and the light requirement of Trichodesmium nitrogen fixation was high relative to its photosynthetic light demand. Meanwhile, light is a crucial parameter driving the physiological state of Trichodesmium, which subsequently determined the C / N metabolism and net dissolved nitrogen release.
Xiang Gong, Wensheng Jiang, Linhui Wang, Huiwang Gao, Emmanuel Boss, Xiaohong Yao, Shuh-Ji Kao, and Jie Shi
Biogeosciences, 14, 2371–2386, https://doi.org/10.5194/bg-14-2371-2017, https://doi.org/10.5194/bg-14-2371-2017, 2017
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The subsurface chlorophyll maximum layer (SCML) forms near the nitracline. By incorporating a piecewise function for the approximate Gaussian vertical profile of chlorophyll, we derive analytical solutions of a specified nutrient–phytoplankton model. Nitracline depth is deeper than SCML depth, and a thinner SCML corresponds to a steeper nitracline. A higher light attenuation coefficient leads to a shallower but steeper nitracline. Nitracline steepness is independent of surface light intensity.
Tsung-Yu Lee, Li-Chin Lee, Jr-Chuan Huang, Shih-Hao Jien, Thomas Hein, Franz Zehetner, Shuh-Ji Kao, and Fuh-Kwo Shiah
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-105, https://doi.org/10.5194/bg-2017-105, 2017
Revised manuscript not accepted
Jr-Chuan Huang, Tsung-Yu Lee, Teng-Chiu Lin, Thomas Hein, Li-Chin Lee, Yu-Ting Shih, Shuh-Ji Kao, Fuh-Kwo Shiah, and Neng-Huei Lin
Biogeosciences, 13, 1787–1800, https://doi.org/10.5194/bg-13-1787-2016, https://doi.org/10.5194/bg-13-1787-2016, 2016
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The mean riverine DIN export of 49 watersheds in Taiwan is ∼ 3800 kg N km−2 yr−1, 18 times the global average. The mean riverine DIN export ratio is 0.30–0.51, which is much higher than the average of 0.20–0.25 of large rivers around the world, indicating excessive N input relative to ecosystem retention capacity. The DIN export ratio is positively related to agriculture input, and levels of human disturbance and watersheds with high DIN export ratios are likely at advanced stages of N excess.
Shuh-Ji Kao, Tzu-Ling Chiang, Da-Wei Li, Yi-Chia Hsin, Li-Wei Zheng, Jin-Yu Terence Yang, Shih-Chieh Hsu, Chau-Ron Wu, and Minhan Dai
Clim. Past Discuss., https://doi.org/10.5194/cp-2015-167, https://doi.org/10.5194/cp-2015-167, 2016
Preprint withdrawn
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A 3-D model was run for the South China Sea to explore the effects of sea level drop and monsoon wind intensity on glacial patterns of circulation and ventilation. Winter northeasterly monsoon wind intensity governs the volume transport of Kuroshio intrusion through the Luzon Strait, subsequently, the water exchange rate and the mean residence time of water body of the SCS.
L. Luo, X. H. Yao, H. W. Gao, S. C. Hsu, J. W. Li, and S. J. Kao
Atmos. Chem. Phys., 16, 325–341, https://doi.org/10.5194/acp-16-325-2016, https://doi.org/10.5194/acp-16-325-2016, 2016
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Concentrations and depositions of various nitrogen species of water-soluble fraction in aerosols were observed during spring over the eastern China seas and northwestern Pacific Ocean. Results revealed nitrogen deposition associated with the sea fog weather was 6 times higher than that of spring supply from the Yangtze River to the ECS shelf. The DON emission had occurred most likely during sea spray. Weather conditions modulate the nitrogen exchange at the ocean-atmosphere boundary.
Y.-T. Shih, T.-Y. Lee, J.-C. Huang, S.-J. Kao, K.-K. Liu, and F.-J. Chang
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hessd-12-449-2015, https://doi.org/10.5194/hessd-12-449-2015, 2015
Revised manuscript not accepted
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This study combines the observed riverine DIN (dissolved inorganic nitrogen) export and the controlling factors (land-use, population and discharge) to inversely estimate the effective DIN yield factors for individual land-use and per capita loading. Those estimated DIN yield factors can extrapolate all possible combinations of land-use, discharge, and population density, demonstrating the capability for scenario assessment.
S.-J. Kao, B.-Y. Wang, L.-W. Zheng, K. Selvaraj, S.-C. Hsu, X. H. Sean Wan, M. Xu, and C.-T. Arthur Chen
Biogeosciences, 12, 1–14, https://doi.org/10.5194/bg-12-1-2015, https://doi.org/10.5194/bg-12-1-2015, 2015
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This paper presents a new sedimentary nitrogen isotope record (d15N) of a sediment core from the southeastern Arabian Sea (AS). By compiling the published nitrogen isotope data in the AS, we obtain geographically distinctive bottom-depth effects for the northern and southern AS since 35ka. After eliminating the bottom-depth bias, we observe opposite d15N trends in the Holocene between these two areas, reflecting a special coupling of denitrification to the north and N2-fixation to the south.
T.-Y. Lee, Y.-T. Shih, J.-C. Huang, S.-J. Kao, F.-K. Shiah, and K.-K. Liu
Biogeosciences, 11, 5307–5321, https://doi.org/10.5194/bg-11-5307-2014, https://doi.org/10.5194/bg-11-5307-2014, 2014
S.-C. Hsu, G.-C. Gong, F.-K. Shiah, C.-C. Hung, S.-J. Kao, R. Zhang, W.-N. Chen, C.-C. Chen, C. C.-K. Chou, Y.-C. Lin, F.-J. Lin, and S.-H. Lin
Atmos. Chem. Phys. Discuss., https://doi.org/10.5194/acpd-14-21433-2014, https://doi.org/10.5194/acpd-14-21433-2014, 2014
Revised manuscript has not been submitted
W.-D. Zhai and H.-D. Zhao
Biogeosciences Discuss., https://doi.org/10.5194/bgd-11-11509-2014, https://doi.org/10.5194/bgd-11-11509-2014, 2014
Revised manuscript not accepted
Y. Zhang, X. Xie, N. Jiao, S. S.-Y. Hsiao, and S.-J. Kao
Biogeosciences, 11, 2131–2145, https://doi.org/10.5194/bg-11-2131-2014, https://doi.org/10.5194/bg-11-2131-2014, 2014
S. S.-Y. Hsiao, T.-C. Hsu, J.-w. Liu, X. Xie, Y. Zhang, J. Lin, H. Wang, J.-Y. T. Yang, S.-C. Hsu, M. Dai, and S.-J. Kao
Biogeosciences, 11, 2083–2098, https://doi.org/10.5194/bg-11-2083-2014, https://doi.org/10.5194/bg-11-2083-2014, 2014
J.-Y. T. Yang, S.-C. Hsu, M. H. Dai, S. S.-Y. Hsiao, and S.-J. Kao
Biogeosciences, 11, 1833–1846, https://doi.org/10.5194/bg-11-1833-2014, https://doi.org/10.5194/bg-11-1833-2014, 2014
S.-J. Kao, R. G. Hilton, K. Selvaraj, M. Dai, F. Zehetner, J.-C. Huang, S.-C. Hsu, R. Sparkes, J. T. Liu, T.-Y. Lee, J.-Y. T. Yang, A. Galy, X. Xu, and N. Hovius
Earth Surf. Dynam., 2, 127–139, https://doi.org/10.5194/esurf-2-127-2014, https://doi.org/10.5194/esurf-2-127-2014, 2014
Y.-F. Tseng, J. Lin, M. Dai, and S.-J. Kao
Biogeosciences, 11, 409–423, https://doi.org/10.5194/bg-11-409-2014, https://doi.org/10.5194/bg-11-409-2014, 2014
T.-C. Hsu and S.-J. Kao
Biogeosciences, 10, 7847–7862, https://doi.org/10.5194/bg-10-7847-2013, https://doi.org/10.5194/bg-10-7847-2013, 2013
N. N. Chang, J. C. Shiao, G. C. Gong, S. J. Kao, and C. H. Hsieh
Biogeosciences Discuss., https://doi.org/10.5194/bgd-10-1051-2013, https://doi.org/10.5194/bgd-10-1051-2013, 2013
Revised manuscript not accepted
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Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
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Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
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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.
Yuyang He, Xiaobin Cao, and Huiming Bao
Biogeosciences, 17, 4785–4795, https://doi.org/10.5194/bg-17-4785-2020, https://doi.org/10.5194/bg-17-4785-2020, 2020
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Different carbon sites in a large organic molecule have different isotope compositions. Different carbon sites may not have the chance to exchange isotopes at all. The lack of appreciation of this notion might be blamed for an unsettled debate on the thermodynamic state of an organism. Here we demonstrate using minerals, N2O, and acetic acid that the dearth of exchange among different carbon sites renders them as independent as if they were different elements in organic molecules.
Felix M. Spielmann, Albin Hammerle, Florian Kitz, Katharina Gerdel, and Georg Wohlfahrt
Biogeosciences, 17, 4281–4295, https://doi.org/10.5194/bg-17-4281-2020, https://doi.org/10.5194/bg-17-4281-2020, 2020
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Carbonyl sulfide (COS) can be used as a proxy for plant photosynthesis on an ecosystem scale. However, the relationships between COS and CO2 fluxes and their dependence on daily to seasonal changes in environmental drivers are still poorly understood. We examined COS and CO2 ecosystem fluxes above an agriculturally used mountain grassland for 6 months. Harvesting of the grassland disturbed the otherwise stable COS-to-CO2 uptake ratio. We even found the canopy to release COS during those times.
Getachew Agmuas Adnew, Thijs L. Pons, Gerbrand Koren, Wouter Peters, and Thomas Röckmann
Biogeosciences, 17, 3903–3922, https://doi.org/10.5194/bg-17-3903-2020, https://doi.org/10.5194/bg-17-3903-2020, 2020
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We measured the effect of photosynthesis, the largest flux in the carbon cycle, on the triple oxygen isotope composition of atmospheric CO2 at the leaf level during gas exchange using three plant species. The main factors that limit the impact of land vegetation on the triple oxygen isotope composition of atmospheric CO2 are identified, characterized and discussed. The effect of photosynthesis on the isotopic composition of CO2 is commonly quantified as discrimination (ΔA).
Moritz Schroll, Frank Keppler, Markus Greule, Christian Eckhardt, Holger Zorn, and Katharina Lenhart
Biogeosciences, 17, 3891–3901, https://doi.org/10.5194/bg-17-3891-2020, https://doi.org/10.5194/bg-17-3891-2020, 2020
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Fungi have recently been identified to produce the greenhouse gas methane. Here, we investigated the stable carbon isotope values of methane produced by saprotrophic fungi. Our results show that stable isotope values of methane from fungi are dependent on the fungal species and the metabolized substrate. They cover a broad range and overlap with stable carbon isotope values of methane reported for methanogenic archaea, the thermogenic degradation of organic matter, and other eukaryotes.
Pranav Hirave, Guido L. B. Wiesenberg, Axel Birkholz, and Christine Alewell
Biogeosciences, 17, 2169–2180, https://doi.org/10.5194/bg-17-2169-2020, https://doi.org/10.5194/bg-17-2169-2020, 2020
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Sediment input into water bodies is a prominent threat to freshwater ecosystems. We tested the stability of tracers employed in freshwater sediment tracing based on compound-specific isotope analysis during early degradation in soil. While bulk δ13C values showed no stability, δ13C values of plant-derived fatty acids and n-alkanes were stably transferred to the soil without soil particle size dependency after an early degradation in organic horizons, thus indicating their suitability as tracers.
Caroline Thaler, Amandine Katz, Magali Bonifacie, Bénédicte Ménez, and Magali Ader
Biogeosciences, 17, 1731–1744, https://doi.org/10.5194/bg-17-1731-2020, https://doi.org/10.5194/bg-17-1731-2020, 2020
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Paleoenvironment reconstructions, retrieved from δ18O and Δ47 values measured in carbonate, are compromised when crystallization occurs in isotopic disequilibrium. We show that some paleoenvironmental information can still be retrieved from these paired disequilibrium Δ47 and δ18O values. The possibility of retrieving information on paleowaters, sediments' interstitial waters, or organisms' body water at the carbonate precipitation loci will help understand past Earth and life evolution.
Cited articles
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Short summary
To resolve multiple N transformation rates, we proposed an innovative “isotope matrix method” to simultaneously derive rates for multiple transformations. This method was designed specifically for incubations in the euphotic zone under simulated in situ light conditions and minimized potential biases caused by non-targeted processes. The method facilitates simple post hoc analysis of data and can be used to probe specific effects of environmental factors on the rates of interactive N processes.
To resolve multiple N transformation rates, we proposed an innovative “isotope matrix...
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