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Gao D, Luster J, Zürcher A, Arend M, Bai E, Gessler A, Rigling A, Schaub M, Hartmann M, Werner RA, Joseph J, Poll C, Hagedorn F. Drought resistance and resilience of rhizosphere communities in forest soils from the cellular to ecosystem scale - insights from 13C pulse labeling. THE NEW PHYTOLOGIST 2024; 242:960-974. [PMID: 38402527 DOI: 10.1111/nph.19612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/06/2024] [Indexed: 02/26/2024]
Abstract
The link between above- and belowground communities is a key uncertainty in drought and rewetting effects on forest carbon (C) cycle. In young beech model ecosystems and mature naturally dry pine forest exposed to 15-yr-long irrigation, we performed 13C pulse labeling experiments, one during drought and one 2 wk after rewetting, tracing tree assimilates into rhizosphere communities. The 13C pulses applied in tree crowns reached soil microbial communities of the young and mature forests one and 4 d later, respectively. Drought decreased the transfer of labeled assimilates relative to the irrigation treatment. The 13C label in phospholipid fatty acids (PLFAs) indicated greater drought reduction of assimilate incorporation by fungi (-85%) than by gram-positive (-43%) and gram-negative bacteria (-58%). 13C label incorporation was more strongly reduced for PLFAs (cell membrane) than for microbial cytoplasm extracted by chloroform. This suggests that fresh rhizodeposits are predominantly used for osmoregulation or storage under drought, at the expense of new cell formation. Two weeks after rewetting, 13C enrichment in PLFAs was greater in previously dry than in continuously moist soils. Drought and rewetting effects were greater in beech systems than in pine forest. Belowground C allocation and rhizosphere communities are highly resilient to drought.
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Affiliation(s)
- Decai Gao
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
- Qianyanzhou Ecological Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 100101, Beijing, China
- College of Resources and Environment, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Jörg Luster
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
| | - Alois Zürcher
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
| | - Matthias Arend
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
- Physiological Plant Ecology, University of Basel, 4056, Basel, Switzerland
| | - Edith Bai
- Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains, Ministry of Education, Northeast Normal University, 130024, Changchun, China
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
- Terrestrial Ecosystems, ETH Zürich, 8092, Zürich, Switzerland
| | - Andreas Rigling
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
- Terrestrial Ecosystems, ETH Zürich, 8092, Zürich, Switzerland
| | - Marcus Schaub
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
| | - Martin Hartmann
- Sustainable Agroecosystems Group, Department of Environmental Systems Science, Institute of Agricultural Sciences, ETH Zürich, 8092, Zürich, Switzerland
| | - Roland A Werner
- Agricultural Sciences, ETH Zürich, 8092, Zürich, Switzerland
| | - Jobin Joseph
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
| | - Christian Poll
- Soil Biology, University of Hohenheim, 70599, Stuttgart, Germany
| | - Frank Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research, 8903, Birmensdorf, Switzerland
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Li Y, Wang M, Zhang D. An improved method for isotopic and quantitative analysis of dissolved organic carbon in natural water samples. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2024; 89:2060-2072. [PMID: 38678409 DOI: 10.2166/wst.2024.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Accepted: 03/26/2024] [Indexed: 04/30/2024]
Abstract
A wet chemical oxidation (WCO) method has been widely used to obtain the dissolved organic carbon (DOC) content and carbon isotope (δ13CDOC) ratios. However, it is sometimes difficult to get high precision results because not enough CO2 was oxidized from the natural water samples with low DOC concentrations. This improvement primarily aims to increase the water sample volume, improve the removal rate of dissolved inorganic carbon (DIC), and minimize the blank DOC from the standard solution. Following the improved procedure, the δ13C ratios of standardized DOC solutions were consistent with their actual values, and their differences were less than 0.2‰. The improved method demonstrated good accuracy and stability when applied to natural water samples with DOC concentrations ≥0.5 mg L-1, with the precisions of DOC concentrations and δ13C ratios were better than 0.07 mg L-1 and 0.1‰, respectively. More importantly, this method saved much pre-treatment time and realized batch processing of water samples to obtain their DOC contents and isotope ratios.
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Affiliation(s)
- Yuhong Li
- School of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, China
| | - Mingshi Wang
- School of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, China
| | - Dong Zhang
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China E-mail:
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Li Y, Wang M, Zhang D, Wang F, Jiang H. The impacts of water-sediment regulation on organic carbon in the Yellow River. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 918:170721. [PMID: 38325462 DOI: 10.1016/j.scitotenv.2024.170721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2023] [Revised: 02/03/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
The Yellow River water-sediment regulation (WSR) is a unique hydraulic engineering project that involves the resuspension and rapid discharge of sediment downstream under the influence of density currents. This process leads to short-term high-intensity sediment scouring, which in turn increases the output of organic carbon. The impact of WSR on the biogeochemical cycling of organic carbon in rivers has not been adequately explored. In this study, we applied stable isotope and 3-D fluorescence analyses to investigate the impact of WSR at the Xiaolangdi (XLD) Reservoir on the sources and fluxes of dissolved organic carbon (DOC) and particulate organic carbon (POC) in the Yellow River. The POC and DOC fluxes during WSR (∼51 days) accounted for 95.5 % and 28.3 % of the annual fluxes. According to the Bayesian model used in the study, the fluxes of POC from sediment, terrestrial plants, and sewage increased by 23.2, 13.36, and 56.55 times, respectively, during the WSR period. On the other hand, the flux from various sources of DOC decreased by ∼0.7 times during the WSR process. The three-dimensional fluorescence index (specific UV absorbance [SUVA254], humification index [HIX], biological index [BIX], and fluorescence index [FI]) further reveals that in the WSR process, more DOC comes from sediment and upstream water. This study provides quantitative insights into the effects of WSR on river organic carbon export dynamics and the driving mechanisms behind them. It also has important implications for understanding the impact of anthropogenic disturbance on the global carbon cycle.
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Affiliation(s)
- Yuhong Li
- School of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, China
| | - Mingshi Wang
- School of Resource and Environment, Henan Polytechnic University, Jiaozuo 454000, China
| | - Dong Zhang
- College of Oceanography and Ecological Science, Shanghai Ocean University, Shanghai 201306, China.
| | - Fushun Wang
- School of Environmental and Chemical Engineering, Shanghai University, Shanghai 20433, China
| | - Hao Jiang
- Danjiangkou Wetland Ecosystem Field Scientific Observation and Research Station, Chinese Academy of Sciences & Hubei Province, Wuhan 430074, China; Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China
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Li H, Liu G, Luo H, Zhang R. Labile carbon-induced soil organic matter turnover in a subtropical forest under different redox conditions. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 348:119387. [PMID: 37879174 DOI: 10.1016/j.jenvman.2023.119387] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 10/09/2023] [Accepted: 10/11/2023] [Indexed: 10/27/2023]
Abstract
Labile organic carbon (LOC) input strongly affects soil organic matter (SOM) dynamics, including gains and losses. However, it is unclear how redox fluctuations regulate these processes of SOM decomposition and formation induced by LOC input. The objective of this study was to explore the impacts of LOC input on SOM turnover under different redox conditions. Soil samples were collected in a subtropical forest. A single pulse of 13C-labeled glucose (i.e., LOC) was applied to the soil. Soil samples were incubated for 40 days under three redox treatments, including aerobic, anoxic, and 10-day aerobic followed by 10-day anoxic conditions. Results showed that LOC input affected soil priming and 13C-SOM accumulation differently under distinct redox conditions by altering the activities of various microorganisms. 13C-PLFAs (phospholipid fatty acids) were analyzed to determine the role of microbial groups in SOM turnover. Increased activities of fungi and gram-positive bacteria (i.e., the K-strategists) by LOC input could ingest metabolites or residues of the r-strategists (e.g., gram-negative bacteria) to result in positive priming. Fungi could use gram-negative bacteria to stimulate priming intensity via microbial turnover in aerobic conditions first. Reduced activities of K-strategists as a result of the aerobic to anoxic transition decreased priming intensity. The difference in LOC retention in SOM under different redox conditions was mainly attributable to 13C-particulate organic carbon (13C-POC) accumulation. Under aerobic conditions, fungi and gram-positive bacteria used derivatives from gram-negative bacteria to reduce newly formed POC. However, anoxic conditions were not conducive to the uptake of gram-negative bacteria by fungi and gram-positive bacteria, favoring SOM retention. This work indicated that redox-regulated microbial activities can control SOM decomposition and formation induced by LOC input. It is extremely valuable for understanding the contribution of soil affected by redox fluctuations to the carbon cycle.
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Affiliation(s)
- Huan Li
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Guangli Liu
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Haiping Luo
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006, China
| | - Renduo Zhang
- Guangdong Provincial Key Laboratory of Environmental Pollution Control and Remediation Technology, School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou, 510006, China.
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Meng L, Xue J, Zhao C, Huang T, Yang H, Zhao K, Yu Z, Yuan L, Zhou Q, Kellerman AM, McKenna AM, Spencer RGM, Huang C. N-containing dissolved organic matter promotes dissolved inorganic carbon supersaturation in the Yangtze River, China. WATER RESEARCH 2023; 247:120808. [PMID: 37924684 DOI: 10.1016/j.watres.2023.120808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 10/24/2023] [Accepted: 10/28/2023] [Indexed: 11/06/2023]
Abstract
Dissolved inorganic carbon (DIC) represents a major global carbon pool and the flux from rivers to oceans has been observed to be increasing. The effect of weathering with respect to increasing DIC has been widely studied in recent decades; however, the influence of dissolved organic matter (DOM) on increasing DIC in large rivers remains unclear. This study employed stable carbon isotopes and Fourier transform ion cyclotron mass spectrometry (FT-ICR MS) to investigate the effect of the molecular composition of DOM on the DIC in the Yangtze River. The results showed that organic matter is an important source of DIC in the Yangtze River, accounting for 40.0 ± 12.1 % and 32.0 ± 7.2 % of DIC in wet and dry seasons, respectively, and increased along the river by approximately three times. Nitrogen (N)-containing DOM, an important composition in DOM with a percentage of ∼40 %, showed superior oxidation state than non N-containing DOM, suggesting that the presence of N could improve the degradable potential of DOM. Positive relationship between organic sourced DIC (DICOC) and N-containing DOM formulae indicated that N-containing DOM is crucial to facilitate the mineralization of DOM to DICOC. N-containg molecular formular with low H/C and O/C ratio were positively correlated with DICOC further verified these energy-rich and biolabile compounds are preferentially decomposed by bacteria to produce DIC. N-containing components significantly accelerated the degradation of DOM to DICOC, which is important for understanding the CO2 emission and carbon cycling in large rivers.
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Affiliation(s)
- Lize Meng
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China
| | - Jingya Xue
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China
| | - Chu Zhao
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China
| | - Tao Huang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China.
| | - Hao Yang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China
| | - Kan Zhao
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China
| | - Zhaoyuan Yu
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China
| | - Linwang Yuan
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China
| | - Qichao Zhou
- Institute for Ecological Research and Pollution Control of Plateau Lakes, School of Ecology and Environmental Sciences, Yunnan University, Kunming 650500, PR China
| | - Anne M Kellerman
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Amy M McKenna
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Robert G M Spencer
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Changchun Huang
- Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, PR China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, PR China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, PR China; School of Geography, Nanjing Normal University, Nanjing 210023, PR China.
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6
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Li Z, Xu W, Kang L, Kuzyakov Y, Chen L, He M, Liu F, Zhang D, Zhou W, Liu X, Yang Y. Accelerated organic matter decomposition in thermokarst lakes upon carbon and phosphorus inputs. GLOBAL CHANGE BIOLOGY 2023; 29:6367-6382. [PMID: 37695465 DOI: 10.1111/gcb.16938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 08/23/2023] [Accepted: 08/27/2023] [Indexed: 09/12/2023]
Abstract
Mineralization of dissolved organic matter (DOM) in thermokarst lakes plays a non-negligible role in the permafrost carbon (C) cycle, but remains poorly understood due to its complex interactions with external C and nutrient inputs (i.e., aquatic priming and nutrient effects). Based on large-scale lake sampling and laboratory incubations, in combination with 13 C-stable-isotope labeling, optical spectroscopy, and high-throughput sequencing, we examined large-scale patterns and dominant drivers of priming and nutrient effects of DOM biodegradation across 30 thermokarst lakes along a 1100-km transect on the Tibetan Plateau. We observed that labile C and phosphorus (P) rather than nitrogen (N) inputs stimulated DOM biodegradation, with the priming and P effects being 172% and 451% over unamended control, respectively. We also detected significant interactive effects of labile C and nutrient supply on DOM biodegradation, with the combined labile C and nutrient additions inducing stronger microbial mineralization than C or nutrient treatment alone, illustrating that microbial activity in alpine thermokarst lakes is co-limited by both C and nutrients. We further found that the aquatic priming was mainly driven by DOM quality, with the priming intensity increasing with DOM recalcitrance, reflecting the limitation of external C as energy sources for microbial activity. Greater priming intensity was also associated with higher community-level ribosomal RNA gene operon (rrn) copy number and bacterial diversity as well as increased background soluble reactive P concentration. In contrast, the P effect decreased with DOM recalcitrance as well as with background soluble reactive P and ammonium concentrations, revealing the declining importance of P availability in mediating DOM biodegradation with enhanced C limitation but reduced nutrient limitation. Overall, the stimulation of external C and P inputs on DOM biodegradation in thermokarst lakes would amplify C-climate feedback in this alpine permafrost region.
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Affiliation(s)
- Ziliang Li
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Weijie Xu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Luyao Kang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yakov Kuzyakov
- Department of Soil Science of Temperate Ecosystems, University of Göttingen, Göttingen, Germany
- Department of Agricultural Soil Science, University of Göttingen, Göttingen, Germany
- Peoples Friendship University of Russia (RUDN University), Moscow, Russia
| | - Leiyi Chen
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Mei He
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Futing Liu
- Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration, Ecology and Nature Conservation Institute, Chinese Academy of Forestry, Beijing, China
| | - Dianye Zhang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Wei Zhou
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xuning Liu
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
| | - Yuanhe Yang
- State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- China National Botanical Garden, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
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7
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Li S, Meng L, Zhao C, Gu Y, Spencer RGM, Álvarez-Salgado XA, Kellerman AM, McKenna AM, Huang T, Yang H, Huang C. Spatiotemporal response of dissolved organic matter diversity to natural and anthropogenic forces along the whole mainstream of the Yangtze River. WATER RESEARCH 2023; 234:119812. [PMID: 36881953 DOI: 10.1016/j.watres.2023.119812] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2023] [Revised: 02/23/2023] [Accepted: 02/24/2023] [Indexed: 06/18/2023]
Abstract
The Yangtze River, the largest river in Asia, plays a crucial role in linking continental and oceanic ecosystems. However, the impact of natural and anthropogenic disturbances on composition and transformation of dissolved organic matter (DOM) during long-distance transport and seasonal cycle is not fully understood. By using a combination of elemental, isotopic and optical techniques, as well as Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), we investigated DOM abundance and composition along the whole mainstream at highly spatial resolution in the dry and early wet seasons. Our findings showed that the concentration and flux of dissolved organic carbon (DOC) in the Yangtze River was much lower compared with other worldwide larger rivers. The distribution of δ13CDOC and higher abundance of humic-like fluorescent component and highly unsaturated and phenolics (HUPs) compound reflected a prominent contribution of allochthonous DOM. Further optical and molecular analysis revealed humic-like fluorescent components were coupled with CHO molecules and HUPs compound with higher aromatic, unsaturated, molecular weight and stable characteristics between upstream and midstream reaches. With increasing agricultural and urban land downstream, there were more heteroatomic formulae and labile aliphatic and protein-like compounds which were derived from human activities and in situ primary production. Meanwhile, DOM gradually accumulates with slow water flow and additional autochthonous organics. Weaker solar radiation and water dilution during the dry/cold season favours highly aromatic, unsaturated and oxygenated DOM compositions. Conversely, higher discharge during the wet/warm season diluted the terrestrial DOM, but warm temperatures could promote phytoplankton growth that releases labile aliphatic and protein-like DOM. Besides, chemical sulfurization, hydrogenation and oxygenation were found during molecular cycling processes. Our research emphasizes the active response of riverine DOM to natural and anthropogenic controls, and provides a valuable preliminary background to better understand the biogeochemical cycling of DOM in a larger river.
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Affiliation(s)
- Shuaidong Li
- School of Geography, Nanjing Normal University, Nanjing 210023, China; Organic Geochemistry Lab, Instituto de Investigacións Mariñas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), Vigo 36208, Spain
| | - Lize Meng
- School of Geography, Nanjing Normal University, Nanjing 210023, China
| | - Chu Zhao
- School of Geography, Nanjing Normal University, Nanjing 210023, China
| | - Yu Gu
- School of Geography, Nanjing Normal University, Nanjing 210023, China
| | - Robert G M Spencer
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Xosé Antón Álvarez-Salgado
- Organic Geochemistry Lab, Instituto de Investigacións Mariñas (IIM), Consejo Superior de Investigaciones Científicas (CSIC), Vigo 36208, Spain
| | - Anne M Kellerman
- Department of Earth, Ocean and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
| | - Amy M McKenna
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Tao Huang
- School of Geography, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, China
| | - Hao Yang
- School of Geography, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, China
| | - Changchun Huang
- School of Geography, Nanjing Normal University, Nanjing 210023, China; Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China; Key Laboratory of Virtual Geographic Environment (Nanjing Normal University), Ministry of Education, Nanjing 210023, China; State Key Laboratory Cultivation Base of Geographical Environment Evolution (Jiangsu Province), Nanjing 210023, China.
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8
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Carvalho MC. Adapting an elemental analyser to perform high-temperature catalytic oxidation for dissolved organic carbon measurements in water. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2023; 37:e9451. [PMID: 36479758 DOI: 10.1002/rcm.9451] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
RATIONALE Many laboratories employ elemental analyzers (EAs) coupled to isotope ratio mass spectrometers (IRMSs) to measure carbon stable isotope ratios (δ13 C) in solid samples. Dissolved organic carbon (DOC) in most natural water samples cannot be analyzed using this approach unless time-consuming preconcentration is employed. METHODS An EA-IRMS can be used to measure DOC δ13 C in natural waters without the need for sample preconcentration by employing high-temperature catalytic oxidation. An autosampler injects water into the EA reactor at 680°C filled with platinum catalyst beads, where all carbon is converted to CO2 . Remaining water and halides are removed, while CO2 is trapped in a cryotrap and later released to the IRMS. RESULTS Measurements were accurate (deviation <0.3‰ compared to solid sample measurements) and precise (error of 0.3‰ for concentrations ≥46 μM). Blanks were present and accounted for. Salinity up to seawater level did not affect accuracy or precision, but limited the number of samples that could be run before cleaning of the reactor was needed. DOC δ13 C in a river/estuary varied between -25.7 and -23.2‰, with higher values for waters with higher salinity, as expected. Deep-sea water reference material had a value of -22.9 ± 0.5‰, very similar to those found in recent reports employing similar techniques. CONCLUSION Adapting an EA is a feasible approach for the measurement of DOC δ13 C in natural waters. The low cost and simplicity of the system allow its use in any laboratory already equipped with EA-IRMS.
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Affiliation(s)
- Matheus C Carvalho
- Southern Cross Analytical Research Services, Southern Cross University, Centre for Coastal Biogeochemistry, Southern Cross University, Lismore, NSW, Australia
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Eliminating the need for anodic gas separation in CO 2 electroreduction systems via liquid-to-liquid anodic upgrading. Nat Commun 2022; 13:3070. [PMID: 35654799 PMCID: PMC9163163 DOI: 10.1038/s41467-022-30677-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 05/09/2022] [Indexed: 11/22/2022] Open
Abstract
Electrochemical reduction of CO2 to multi-carbon products (C2+), when powered using renewable electricity, offers a route to valuable chemicals and fuels. In conventional neutral-media CO2-to-C2+ devices, as much as 70% of input CO2 crosses the cell and mixes with oxygen produced at the anode. Recovering CO2 from this stream adds a significant energy penalty. Here we demonstrate that using a liquid-to-liquid anodic process enables the recovery of crossed-over CO2 via facile gas-liquid separation without additional energy input: the anode tail gas is directly fed into the cathodic input, along with fresh CO2 feedstock. We report a system exhibiting a low full-cell voltage of 1.9 V and total carbon efficiency of 48%, enabling 262 GJ/ton ethylene, a 46% reduction in energy intensity compared to state-of-art single-stage CO2-to-C2+ devices. The strategy is compatible with today’s highest-efficiency electrolyzers and CO2 catalysts that function optimally in neutral and alkaline electrolytes. In the electrified conversion of CO2 to multicarbon products, CO2 crossover to the O2-rich anodic stream adds a further, energy-intensive, chemical separation step. Here, the authors demonstrate a strategy that eliminates the separation requirement.
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10
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Sun C, Liu J, Li M, Zang J, Wang L, Wu W, Zhang A, Wang J, Ran X. Inventory of riverine dissolved organic carbon in the Bohai Rim. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2022; 293:118601. [PMID: 34848286 DOI: 10.1016/j.envpol.2021.118601] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 11/05/2021] [Accepted: 11/26/2021] [Indexed: 06/13/2023]
Abstract
Riverine carbon (C) composition and export are closely related to changes in the coastal environment and climate. Excessive C inputs from rivers to seas and their subsequent decomposition could result in harmful algal blooms and ecosystem degradation in the coastal sea. In this study, we explored the C transportation and composition in the 24 major rivers of the Bohai Sea (BS) Rim based on the investigation of dissolved organic carbon (DOC), carbon stable isotopes (δ13CDOC) and chromophoric dissolved organic matter (CDOM). The results showed that the riverine DOC concentrations were high (10.6 ± 6.04 mg/L) in the BS Rim compared with the DOC levels in the main rivers in Eastern China (4.98 ± 2.45 mg/L). The δ13CDOC ranged from -28.29‰ to -25.32‰ in the rivers of the BS Rim, suggesting that the DOC mainly originated from riverine plankton, soil organic matter mainly induced by C3 plants, and sewage. The excitation-emission matrix fluorescence spectroscopy of the CDOM indicated that a soluble, microbial by product-like material accounted for the largest proportion (approximately 40%) of CDOM in these rivers and that CDOM mainly originated from autochthonous riverine sources with high protein-like components. The rivers in the BS Rim transported approximately 0.55 Tg C of DOC to the BS each year, with more than 70% of reactive C based on the CDOM composition. The DOC yields in terms of unit drainage area transported from the small rivers to the BS were higher compared to those of the larger rivers in the world, which indicated that the small rivers in the Bohai Rim could be an important source of the C in the BS. This study would enrich our understanding of environmental evolution in coastal areas with numerous small rivers.
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Affiliation(s)
- Cece Sun
- Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China
| | - Jun Liu
- Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China; Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, PR China; Key Laboratory of Marine Eco-Environmental Science and Technology, Ministry of Natural Resources, Qingdao, 266061, PR China.
| | - Menglu Li
- Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China
| | - Jiaye Zang
- Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China; Key Laboratory of Marine Eco-Environmental Science and Technology, Ministry of Natural Resources, Qingdao, 266061, PR China
| | - Lu Wang
- Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, PR China
| | - Wentao Wu
- Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China; Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Ocean University of China, Qingdao, 266100, PR China
| | - Aijun Zhang
- Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China; Key Laboratory of Marine Eco-Environmental Science and Technology, Ministry of Natural Resources, Qingdao, 266061, PR China
| | - Junjie Wang
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Princetonlaan 8a, 3584 CB, Utrecht, the Netherlands
| | - Xiangbin Ran
- Research Center for Marine Ecology, First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, PR China; Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao, 266237, PR China; Key Laboratory of Marine Eco-Environmental Science and Technology, Ministry of Natural Resources, Qingdao, 266061, PR China
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11
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Gao D, Joseph J, Werner RA, Brunner I, Zürcher A, Hug C, Wang A, Zhao C, Bai E, Meusburger K, Gessler A, Hagedorn F. Drought alters the carbon footprint of trees in soils-tracking the spatio-temporal fate of 13 C-labelled assimilates in the soil of an old-growth pine forest. GLOBAL CHANGE BIOLOGY 2021; 27:2491-2506. [PMID: 33739617 PMCID: PMC8251913 DOI: 10.1111/gcb.15557] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 01/22/2021] [Accepted: 02/03/2021] [Indexed: 05/04/2023]
Abstract
Above and belowground compartments in ecosystems are closely coupled on daily to annual timescales. In mature forests, this interlinkage and how it is impacted by drought is still poorly understood. Here, we pulse-labelled 100-year-old trees with 13 CO2 within a 15-year-long irrigation experiment in a naturally dry pine forest to quantify how drought regime affects the transfer and use of assimilates from trees to the rhizosphere and associated microbial communities. It took 4 days until new 13 C-labelled assimilates were allocated to the rhizosphere. One year later, the 13 C signal of the 3-h long pulse labelling was still detectable in stem and soil respiration, which provides evidence that parts of the assimilates are stored in trees before they are used for metabolic processes in the rhizosphere. Irrigation removing the natural water stress reduced the mean C residence time from canopy uptake until soil respiration from 89 to 40 days. Moreover, irrigation increased the amount of assimilates transferred to and respired in the soil within the first 10 days by 370%. A small precipitation event rewetting surface soils altered this pattern rapidly and reduced the effect size to +35%. Microbial biomass incorporated 46 ± 5% and 31 ± 7% of the C used in the rhizosphere in the dry control and irrigation treatment respectively. Mapping the spatial distribution of soil-respired 13 CO2 around the 10 pulse-labelled trees showed that tree rhizospheres extended laterally 2.8 times beyond tree canopies, implying that there is a strong overlap of the rhizosphere among adjacent trees. Irrigation increased the rhizosphere area by 60%, which gives evidence of a long-term acclimation of trees and their rhizosphere to the drought regime. The moisture-sensitive transfer and use of C in the rhizosphere has consequences for C allocation within trees, soil microbial communities and soil carbon storage.
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Affiliation(s)
- Decai Gao
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
- Key Laboratory of Geographical Processes and Ecological Security of Changbai MountainsMinistry of EducationNortheast Normal UniversityChangchunChina
| | - Jobin Joseph
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
| | - Roland A Werner
- Department of Environmental Systems ScienceETH ZurichZurichSwitzerland
| | - Ivano Brunner
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
| | - Alois Zürcher
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
| | - Christian Hug
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
| | - Ao Wang
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
- Terrestrial EcosystemsETH ZurichZurichSwitzerland
| | - Chunhong Zhao
- Key Laboratory of Geographical Processes and Ecological Security of Changbai MountainsMinistry of EducationNortheast Normal UniversityChangchunChina
| | - Edith Bai
- Key Laboratory of Geographical Processes and Ecological Security of Changbai MountainsMinistry of EducationNortheast Normal UniversityChangchunChina
| | | | - Arthur Gessler
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
- Terrestrial EcosystemsETH ZurichZurichSwitzerland
| | - Frank Hagedorn
- Swiss Federal Research Institute WSLBirmensdorfSwitzerland
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12
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McCabe KM, Smith EM, Lang SQ, Osburn CL, Benitez-Nelson CR. Particulate and Dissolved Organic Matter in Stormwater Runoff Influences Oxygen Demand in Urbanized Headwater Catchments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:952-961. [PMID: 33405913 DOI: 10.1021/acs.est.0c04502] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Increasing inputs of organic matter (OM) are driving declining dissolved oxygen (DO) concentrations in coastal ecosystems worldwide. The quantity, source, and composition of OM transported to coastal ecosystems via stormwater runoff have been altered by land use changes associated with urbanization and subsequent hydrologic flows that accompany urban stormwater management. To elucidate the role of stormwater in the decline of coastal DO, rain event sampling of biochemical oxygen demand (BOD) in samples collected from the outfall of stormwater ponds and wetlands, as well as samples of largely untreated runoff carried by stormwater ditches, was conducted across a range of urban and suburban development densities. Sampling also included measurements of particulate and dissolved carbon and nitrogen, carbon and nitrogen stable isotopes, and chlorophyll-a. Results suggest stormwater may be a significant source of labile OM to receiving waters, especially during the first flush of runoff, even though BOD concentrations vary both among and within sites in response to rain events. BOD variability was best predicted by particulate OM (POM) and chlorophyll-a, rather than the larger pool of dissolved OM. These findings demonstrate the importance of managing episodic stormwater discharge, especially POM, from urbanized areas to mitigate DO impairment in larger downstream systems.
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Affiliation(s)
- Kelly M McCabe
- School of Earth, Ocean and Environment, University of South Carolina, Columbia, South Carolina 29208-0001, United States
| | - Erik M Smith
- School of Earth, Ocean and Environment, University of South Carolina, Columbia, South Carolina 29208-0001, United States
- Belle W. Baruch Institute for Marine and Coastal Sciences, University of South Carolina, South Carolina 29208, United States
- North Inlet-Winyah Bay National Estuarine Research Reserve, Georgetown, South Carolina 29440, United States
| | - Susan Q Lang
- School of Earth, Ocean and Environment, University of South Carolina, Columbia, South Carolina 29208-0001, United States
| | - Christopher L Osburn
- Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695, United States
| | - Claudia R Benitez-Nelson
- School of Earth, Ocean and Environment, University of South Carolina, Columbia, South Carolina 29208-0001, United States
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13
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Schwab MS, Hilton RG, Raymond PA, Haghipour N, Amos E, Tank SE, Holmes RM, Tipper ET, Eglinton TI. An Abrupt Aging of Dissolved Organic Carbon in Large Arctic Rivers. GEOPHYSICAL RESEARCH LETTERS 2020; 47:e2020GL088823. [PMID: 33380763 PMCID: PMC7757186 DOI: 10.1029/2020gl088823] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 10/06/2020] [Accepted: 10/14/2020] [Indexed: 06/12/2023]
Abstract
Permafrost thaw in Arctic watersheds threatens to mobilize hitherto sequestered carbon. We examine the radiocarbon activity (F14C) of dissolved organic carbon (DOC) in the northern Mackenzie River basin. From 2003-2017, DOC-F14C signatures (1.00 ± 0.04; n = 39) tracked atmospheric 14CO2, indicating export of "modern" carbon. This trend was interrupted in June 2018 by the widespread release of aged DOC (0.85 ± 0.16, n = 28) measured across three separate catchment areas. Increased nitrate concentrations in June 2018 lead us to attribute this pulse of 14C-depleted DOC to mobilization of previously frozen soil organic matter. We propose export through lateral perennial thaw zones that occurred at the base of the active layer weakened by preceding warm summer and winter seasons. Although we are not yet able to ascertain the broader significance of this "anomalous" mobilization event, it highlights the potential for rapid and large-scale release of aged carbon from permafrost.
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Affiliation(s)
| | | | - Peter A. Raymond
- Yale School of Forestry and Environmental StudiesYale UniversityNew HavenCTUSA
| | - Negar Haghipour
- Department of Earth SciencesETH ZurichZurichSwitzerland
- Laboratory of Ion Beam PhysicsETH ZurichZurichSwitzerland
| | - Edwin Amos
- Aurora Research InstituteInuvikNorthwest TerritoriesCanada
| | - Suzanne E. Tank
- Department of Biological SciencesUniversity of AlbertaEdmontonAlbertaCanada
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14
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Wilson J, Munizzi J, Erhardt AM. Preservation methods for the isotopic composition of dissolved carbon species in non-ideal conditions. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8903. [PMID: 33463814 DOI: 10.1002/rcm.8903] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/17/2020] [Accepted: 07/20/2020] [Indexed: 06/12/2023]
Abstract
RATIONALE The stable carbon isotope compositions of dissolved inorganic carbon (δ13CDIC) and dissolved organic carbon (δ13CDOC) are readily affected by post-sampling microbial activity if not adequately preserved. Existing preservation methods require rapid chilling, analysis, and/or toxic chemicals, all challenging to use safely in the field and during remote field seasons. Therefore, a preservation method that is safe but also effective over a range of storage times is needed when sampling waters at very remote sites. METHODS Two samples, with different dissolved inorganic carbon (DIC) and dissolved organic carbon (DOC) concentrations, were filtered with a 0.2-μm filter and preserved with six different methods, mercuric chloride, copper sulfate, phosphoric acid, benzalkonium chloride, zinc chloride, hydrochloric acid, and a filter-only control. These samples were held at 4°C, 22°C, or 35°C. Regular measurement of the DIC and DOC δ13C values were made over the following 60 days for δ13CDIC and 66 days for δ13CDOC. RESULTS: Over the course of the experiment, mercuric chloride, copper sulfate, zinc chloride, and benzalkonium chloride resulted in δ13CDIC fractionation at both 4°C and 22°C. Only filtering to 0.2 μm at the time of collection, with or without acidification with phosphoric acid, resulted in minimal isotopic fractionation at both 4°C and 22°C and over the entirety of the experiment. For δ13CDOC values, only filtering to 0.2 μm minimized fractionation for both bulk and vial storage over 66 days at 22°C. CONCLUSIONS Filtering to 0.2 μm at the time of collection is more effective than the use of toxic chemicals for measuring δ13CDIC and δ13CDOC values. Phosphoric acid is as effective as only filtering for δ13CDIC and may be ideal depending on sampling considerations. These results demonstrate not only that water samples can be preserved for δ13CDIC and δ13CDOC analysis for long periods, but that preservation is best accomplished with non-toxic or low-toxicity methods.
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Affiliation(s)
- Jonathan Wilson
- Department of Earth and Environmental Sciences, University of Kentucky, Slone Research Building, 121 Washington Ave, Lexington, KY, 40506, USA
| | - Jordon Munizzi
- Department of Earth and Environmental Sciences, University of Kentucky, Slone Research Building, 121 Washington Ave, Lexington, KY, 40506, USA
| | - Andrea M Erhardt
- Department of Earth and Environmental Sciences, University of Kentucky, Slone Research Building, 121 Washington Ave, Lexington, KY, 40506, USA
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15
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Rhizosphere activity in an old-growth forest reacts rapidly to changes in soil moisture and shapes whole-tree carbon allocation. Proc Natl Acad Sci U S A 2020; 117:24885-24892. [PMID: 32958662 DOI: 10.1073/pnas.2014084117] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Drought alters carbon (C) allocation within trees, thereby impairing tree growth. Recovery of root and leaf functioning and prioritized C supply to sink tissues after drought may compensate for drought-induced reduction of assimilation and growth. It remains unclear if C allocation to sink tissues during and following drought is controlled by altered sink metabolic activities or by the availability of new assimilates. Understanding such mechanisms is required to predict forests' resilience to a changing climate. We investigated the impact of drought and drought release on C allocation in a 100-y-old Scots pine forest. We applied 13CO2 pulse labeling to naturally dry control and long-term irrigated trees and tracked the fate of the label in above- and belowground C pools and fluxes. Allocation of new assimilates belowground was ca. 53% lower under nonirrigated conditions. A short rainfall event, which led to a temporary increase in the soil water content (SWC) in the topsoil, strongly increased the amounts of C transported belowground in the nonirrigated plots to values comparable to those in the irrigated plots. This switch in allocation patterns was congruent with a tipping point at around 15% SWC in the response of the respiratory activity of soil microbes. These results indicate that the metabolic sink activity in the rhizosphere and its modulation by soil moisture can drive C allocation within adult trees and ecosystems. Even a subtle increase in soil moisture can lead to a rapid recovery of belowground functions that in turn affects the direction of C transport in trees.
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16
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McBride SG, Choudoir M, Fierer N, Strickland MS. Volatile organic compounds from leaf litter decomposition alter soil microbial communities and carbon dynamics. Ecology 2020; 101:e03130. [PMID: 32621285 DOI: 10.1002/ecy.3130] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 03/25/2020] [Accepted: 05/05/2020] [Indexed: 01/09/2023]
Abstract
Investigations into the transfer of carbon from plant litter to underlying soil horizons have primarily focused on the leaching of soluble carbon from litter belowground or the mixing of litter directly into soil. However, previous work has largely ignored the role of volatile organic compounds (VOCs) released during litter decomposition. Unlike most leaf carbon, these litter-derived VOCs are able to diffuse directly into the soil matrix. Here, we used a 99-d microcosm experiment to track VOCs produced during microbial decomposition of 13 C-labeled leaf litter into soil carbon fractions where the decomposing litters were only sharing headspace with the soil samples, thus preventing direct contact and aqueous movement of litter carbon. We also determined the effects of these litter-derived VOCs on soil microbial community structure. We demonstrated that the litter VOCs contributed to all measured soil carbon pools. Specifically, VOC-derived carbon accounted for 2.0, 0.61, 0.18, and 0.08% of carbon in the microbial biomass, dissolved organic matter, mineral-associated organic matter, and particulate organic matter pools, respectively. We also show that litter-derived VOCs can affect soil bacterial and fungal community diversity and composition. These findings highlight the importance of an underappreciated pathway where VOCs alter soil microbial communities and carbon dynamics.
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Affiliation(s)
- Steven G McBride
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, 24061, USA
| | - Mallory Choudoir
- Cooperative Institute for Research in Environmental Studies (CIRES), University of Colorado Boulder, Boulder, Colorado, 80309, USA
| | - Noah Fierer
- Cooperative Institute for Research in Environmental Studies (CIRES), University of Colorado Boulder, Boulder, Colorado, 80309, USA.,Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado, 80309, USA
| | - Michael S Strickland
- Department of Soil and Water Systems, University of Idaho, Moscow, Idaho, 83844, USA
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17
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Huang W, Ye C, Hockaday WC, Hall SJ. Trade-offs in soil carbon protection mechanisms under aerobic and anaerobic conditions. GLOBAL CHANGE BIOLOGY 2020; 26:3726-3737. [PMID: 32227617 DOI: 10.1111/gcb.15100] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/05/2020] [Accepted: 03/23/2020] [Indexed: 06/10/2023]
Abstract
Oxygen (O2 ) limitation is generally understood to suppress oil carbon (C) decomposition and is a key mechanism impacting terrestrial C stocks under global change. Yet, O2 limitation may differentially impact kinetic or thermodynamic versus physicochemical C protection mechanisms, challenging our understanding of how soil C may respond to climate-mediated changes in O2 dynamics. Although O2 limitation may suppress decomposition of new litter C inputs, release of physicochemically protected C due to iron (Fe) reduction could potentially sustain soil C losses. To test this trade-off, we incubated two disparate upland soils that experience periodic O2 limitation-a tropical rainforest Oxisol and a temperate cropland Mollisol-with added litter under either aerobic (control) or anaerobic conditions for 1 year. Anoxia suppressed total C loss by 27% in the Oxisol and by 41% in the Mollisol relative to the control, mainly due to the decrease in litter-C decomposition. However, anoxia sustained or even increased decomposition of native soil-C (11.0% vs. 12.4% in the control for the Oxisol and 12.5% vs. 5.3% in the control for the Mollisol, in terms of initial soil C mass), and it stimulated losses of metal- or mineral-associated C. Solid-state 13 C nuclear magnetic resonance spectroscopy demonstrated that anaerobic conditions decreased protein-derived C but increased lignin- and carbohydrate-C relative to the control. Our results indicate a trade-off between physicochemical and kinetic/thermodynamic C protection mechanisms under anaerobic conditions, whereby decreased decomposition of litter C was compensated by more extensive loss of mineral-associated soil C in both soils. This challenges the common assumption that anoxia inherently protects soil C and illustrates the vulnerability of mineral-associated C under anaerobic events characteristic of a warmer and wetter future climate.
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Affiliation(s)
- Wenjuan Huang
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Chenglong Ye
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
- Ecosystem Ecology Lab, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | | | - Steven J Hall
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
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18
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Sun P, He S, Yuan Y, Yu S, Zhang C. Effects of aquatic phototrophs on seasonal hydrochemical, inorganic, and organic carbon variations in a typical karst basin, Southwest China. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:32836-32851. [PMID: 31502044 DOI: 10.1007/s11356-019-06374-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 08/29/2019] [Indexed: 06/10/2023]
Abstract
Karst processes play an important role in the global carbon cycle. Aquatic phototrophs can transform bicarbonate, which is mainly derived from the weathering of carbonates, into organic carbon. Carbonate mineral weathering coupled with aquatic photosynthesis can be considered a stable and durable carbon sink process. In this study, we addressed seasonal variations in water chemistry in the Lijiang River Basin, which is a typical karst basin, through a comprehensive geochemical study of the river water in four seasons. The parameters were measured in situ, including major ions and isotopes of inorganic and organic carbon. The results showed that (1) DIC was mainly derived from the weathering of carbonates; (2) the transformation from bicarbonate to organic carbon by aquatic phototrophs was evident, and the water chemistry changed, especially in spring and autumn and in the mainstream from Guilin to Yangshuo, which benefited the growth of aquatic phototrophs; and (3) the organic carbon derived from bicarbonates by aquatic phototrophs was nearly half the total organic carbon and 8% of the dissolved inorganic carbon. These results imply that aquatic phototrophs in karst basins can significantly stabilize carbon originating from carbonate rock weathering processes in karst areas.
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Affiliation(s)
- Ping'an Sun
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China.
- State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences, Wuhan, 430074, China.
| | - Shiyi He
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
| | - Yaqiong Yuan
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
| | - Shi Yu
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
| | - Cheng Zhang
- Key Laboratory of Karst Dynamics, Ministry of Natural Resources & Guangxi, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin, 541004, China
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19
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Kumar M, Snow DD, Li Y, Shea PJ. Perchlorate behavior in the context of black carbon and metal cogeneration following fireworks emission at Oak Lake, Lincoln, Nebraska, USA. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2019; 253:930-938. [PMID: 31351301 DOI: 10.1016/j.envpol.2019.07.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/24/2019] [Accepted: 07/08/2019] [Indexed: 06/10/2023]
Abstract
The imprints of fireworks displays on the adjacent water body were investigated from the perspective of cogeneration of black carbon, metals and perchlorate (ClO4-). In particular, the mixing and dissipation of ClO4- were studied at Oak Lake, Lincoln, Nebraska, following fireworks displays in 2015 and 2016. Following the display, ClO4- concentration in the water increased up to 4.3 μg/L and 4.0 μg/L in 2015 and 2016, respectively. A first-order model generally provided a good fit to the measured perchlorate concentrations from which the rate of dissipation was estimated as 0.07 d-1 in 2015 and 0.43 d-1 in 2016. SEM images show imprints of soot and metal particles in aerosol samples. EDS analysis of the lake sediment confirmed the presence of Si, K, Ca, Zn and Ba, most of which are components of fireworks. The δ13C range of -7.55‰ to -9.19‰ in the lake water system closely resembles fire-generated carbon. Cogeneration of black carbon and metal with perchlorate was established, indicating that ClO4- is an excellent marker of fireworks or a burning event over all other analyzed parameters. Future microcosmic, aggregation and column-based transport studies on black carbon in the presence of perchlorate and metals under different environmental conditions will help in developing transport and fate models for perchlorate and black carbon particles.
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Affiliation(s)
- Manish Kumar
- Discipline of Earth Science, Indian Institute of Technology Gandhinagar, Gujarat 382-355, India.
| | - Daniel D Snow
- Water Sciences Laboratory, University of Nebraska-Lincoln, Lincoln, NE 68588-6105, USA
| | - Yusong Li
- Department of Civil Engineering, University of Nebraska-Lincoln, Lincoln, NE 68583-0844, USA
| | - Patrick J Shea
- School of Natural Resources, University of Nebraska-Lincoln, Lincoln, NE 68583-0817, USA
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20
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Coppola AI, Seidel M, Ward ND, Viviroli D, Nascimento GS, Haghipour N, Revels BN, Abiven S, Jones MW, Richey JE, Eglinton TI, Dittmar T, Schmidt MWI. Marked isotopic variability within and between the Amazon River and marine dissolved black carbon pools. Nat Commun 2019; 10:4018. [PMID: 31488815 PMCID: PMC6728373 DOI: 10.1038/s41467-019-11543-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 07/11/2019] [Indexed: 11/29/2022] Open
Abstract
Riverine dissolved organic carbon (DOC) contains charcoal byproducts, termed black carbon (BC). To determine the significance of BC as a sink of atmospheric CO2 and reconcile budgets, the sources and fate of this large, slow-cycling and elusive carbon pool must be constrained. The Amazon River is a significant part of global BC cycling because it exports an order of magnitude more DOC, and thus dissolved BC (DBC), than any other river. We report spatially resolved DBC quantity and radiocarbon (Δ14C) measurements, paired with molecular-level characterization of dissolved organic matter from the Amazon River and tributaries during low discharge. The proportion of BC-like polycyclic aromatic structures decreases downstream, but marked spatial variability in abundance and Δ14C values of DBC molecular markers imply dynamic sources and cycling in a manner that is incongruent with bulk DOC. We estimate a flux from the Amazon River of 1.9–2.7 Tg DBC yr−1 that is composed of predominately young DBC, suggesting that loss processes of modern DBC are important. Black carbon produced by the burning of biomass and fuels is the most stable carbon compound in nature, yet its path from land to the deep ocean where it persists for thousands of years remains mysterious. Here Coppola and colleagues characterize the black carbon exported by the Amazon River, the largest river in the world.
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Affiliation(s)
- Alysha I Coppola
- Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
| | - Michael Seidel
- Research Group for Marine Geochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, D-26129, Oldenburg, Germany
| | - Nicholas D Ward
- Marine Sciences Laboratory, Pacific Northwest National Laboratory, 1529 West Sequim Bay Road, Sequim, WA, 98382, USA.,School of Oceanography, University of Washington, Box 355351, Seattle, WA, 98195, USA
| | - Daniel Viviroli
- Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Gabriela S Nascimento
- Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.,Geological Institute, Department of Earth Sciences, ETH Zürich, Sonneggstrasse 5, 8092, Zürich, Switzerland
| | - Negar Haghipour
- Geological Institute, Department of Earth Sciences, ETH Zürich, Sonneggstrasse 5, 8092, Zürich, Switzerland.,Laboratory of Ion Beam Physics, ETH Zürich, Otto-Stern-Weg 5, 8093, Zürich, Switzerland
| | - Brandi N Revels
- Geological Institute, Department of Earth Sciences, ETH Zürich, Sonneggstrasse 5, 8092, Zürich, Switzerland
| | - Samuel Abiven
- Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
| | - Matthew W Jones
- Tyndall Centre for Climate Change Research, School of Environmental Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Jeffrey E Richey
- School of Oceanography, University of Washington, Box 355351, Seattle, WA, 98195, USA
| | - Timothy I Eglinton
- Geological Institute, Department of Earth Sciences, ETH Zürich, Sonneggstrasse 5, 8092, Zürich, Switzerland
| | - Thorsten Dittmar
- Research Group for Marine Geochemistry, Institute for Chemistry and Biology of the Marine Environment (ICBM), University of Oldenburg, D-26129, Oldenburg, Germany.,Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstraße 231, 26129, Oldenburg, Germany
| | - Michael W I Schmidt
- Department of Geography, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
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21
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Eickenbusch P, Takai K, Sissman O, Suzuki S, Menzies C, Sakai S, Sansjofre P, Tasumi E, Bernasconi SM, Glombitza C, Jørgensen BB, Morono Y, Lever MA. Origin of Short-Chain Organic Acids in Serpentinite Mud Volcanoes of the Mariana Convergent Margin. Front Microbiol 2019; 10:1729. [PMID: 31404165 PMCID: PMC6677109 DOI: 10.3389/fmicb.2019.01729] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 07/12/2019] [Indexed: 11/17/2022] Open
Abstract
Serpentinitic systems are potential habitats for microbial life due to frequently high concentrations of microbial energy substrates, such as hydrogen (H2), methane (CH4), and short-chain organic acids (SCOAs). Yet, many serpentinitic systems are also physiologically challenging environments due to highly alkaline conditions (pH > 10) and elevated temperatures (>80°C). To elucidate the possibility of microbial life in deep serpentinitic crustal environments, International Ocean Discovery Program (IODP) Expedition 366 drilled into the Yinazao, Fantangisña, and Asùt Tesoru serpentinite mud volcanoes on the Mariana Forearc. These mud volcanoes differ in temperature (80, 150, 250°C, respectively) of the underlying subducting slab, and in the porewater pH (11.0, 11.2, 12.5, respectively) of the serpentinite mud. Increases in formate and acetate concentrations across the three mud volcanoes, which are positively correlated with temperature in the subducting slab and coincide with strong increases in H2 concentrations, indicate a serpentinization-related origin. Thermodynamic calculations suggest that formate is produced by equilibrium reactions with dissolved inorganic carbon (DIC) + H2, and that equilibration continues during fluid ascent at temperatures below 80°C. By contrast, the mechanism(s) of acetate production are not clear. Besides formate, acetate, and H2 data, we present concentrations of other SCOAs, methane, carbon monoxide, and sulfate, δ13C-data on bulk carbon pools, and microbial cell counts. Even though calculations indicate a wide range of microbial catabolic reactions to be thermodynamically favorable, concentration profiles of potential energy substrates, and very low cell numbers suggest that microbial life is scarce or absent. We discuss the potential roles of temperature, pH, pressure, and dispersal in limiting the occurrence of microbial life in deep serpentinitic environments.
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Affiliation(s)
- Philip Eickenbusch
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zurich, Switzerland
| | - Ken Takai
- SUGAR Program, Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-star), Japan Agency for Marine-Earth Science Technology, Yokosuka, Japan
| | | | - Shino Suzuki
- Geomicrobiology Research Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan
| | - Catriona Menzies
- Ocean and Earth Science, National Oceanography Centre, University of Southampton, Southampton, United Kingdom.,Department of Geology and Petroleum Geology, University of Aberdeen, Aberdeen, United Kingdom
| | - Sanae Sakai
- SUGAR Program, Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-star), Japan Agency for Marine-Earth Science Technology, Yokosuka, Japan
| | - Pierre Sansjofre
- Laboratoire Géosciences Océan UMR 6538, Université de Bretagne Occidentale, Brest, France
| | - Eiji Tasumi
- SUGAR Program, Institute for Extra-Cutting-Edge Science and Technology Avant-Garde Research (X-star), Japan Agency for Marine-Earth Science Technology, Yokosuka, Japan
| | | | - Clemens Glombitza
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zurich, Switzerland.,NASA Ames Research Center, Moffett Field, CA, United States
| | - Bo Barker Jørgensen
- Department of Bioscience, Center for Geomicrobiology, Aarhus University, Aarhus, Denmark
| | - Yuki Morono
- Geomicrobiology Research Group, Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology, Kochi, Japan
| | - Mark Alexander Lever
- Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, Zurich, Switzerland
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22
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Skrzypek G, Ford D. Reference materials selection for the stable carbon isotope analysis of dissolved carbon using a wet oxidation system. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2019; 33:473-481. [PMID: 30421830 DOI: 10.1002/rcm.8351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/06/2018] [Accepted: 11/07/2018] [Indexed: 06/09/2023]
Abstract
RATIONALE Wet chemical oxidation combined with isotope ratio mass spectrometry has become a routine technique for analyzing the stable carbon isotope composition of dissolved organic (DOC) and inorganic (DIC) carbon. However, methodological inconsistencies between laboratories in using different reference materials lead to a discrepancy in results. We experimentally tested the precision and accuracy of the analysis of commonly available international reference materials and other chemicals potentially suitable for laboratory standards. METHODS The solid international reference materials and other simple chemicals were used to prepare water solutions. A range of carbon concentrations was chosen to optimize tests for (1) precision and accuracy, (2) linearity, (3) detection limits, (4) memory effects, and (5) efficiency of DIC removal from a DOC/DIC mixtures. Samples were analyzed using an LC-IsoLink coupled with a Delta V Plus isotope ratio mass spectrometer (Thermo Fisher Scientific). RESULTS The analytical setup had a negligible memory effect, good reproducibility (<0.21‰) and accuracy (maximum difference from the true values <0.35‰) for the analyzed organic compounds if approximately ≥9 × 10-09 moles of dissolved carbon was injected into the system (~11 mg C L-1 if a 10-μL loop was used). Analyses of sodium bicarbonate or calcium carbonate solutions had a two-fold lower accuracy despite maintaining a high precision. CONCLUSIONS Aqueous solutions of international reference materials such as L-glutamic acids (USGS40, USGS41), benzoic acid (IAEA-601) and sucrose (IAEA-CH-6) can be successfully used for direct normalization of results to the VPDB scale. By contrast, analyses of caffeine and urea returned very reproducible but highly inaccurate results and these materials are not recommended for standards.
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Affiliation(s)
- Grzegorz Skrzypek
- West Australian Biogeochemistry Centre, School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
| | - Douglas Ford
- West Australian Biogeochemistry Centre, School of Biological Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
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23
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Suess E, Aemisegger F, Sonke JE, Sprenger M, Wernli H, Winkel LHE. Marine versus Continental Sources of Iodine and Selenium in Rainfall at Two European High-Altitude Locations. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:1905-1917. [PMID: 30658037 DOI: 10.1021/acs.est.8b05533] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The essential elements selenium (Se) and iodine (I) are often present in low levels in terrestrial diets, leading to potential deficiencies. Marine I and Se emissions and subsequent atmospheric wet deposition has been suggested to be an important source of I and Se to soils and terrestrial food chains. However, the contribution of recycled moisture of continental origin to I and Se to precipitation has never been analyzed. Here we report concentrations and speciation of I and Se, as well as of bromine (Br), sulfur (S), and DOC-δ13C signatures for weekly collected precipitation samples (in the period of April 2015 to September 2016) at two high altitude sites, i.e., Jungfraujoch (JFJ; Switzerland) and Pic du Midi (PDM; France). Analysis of precipitation chemistry and moisture sources indicate combined marine and continental sources of precipitation and Se, I, Br, and S at both sites. At JFJ, concentrations of I and Se were highest when continental moisture sources were dominant, indicating important terrestrial sources for these elements. Furthermore, correlations between investigated elements and DOC-δ13C, particularly when continental moisture source contributions were high, indicate a link between these elements and the source of dissolved organic matter, especially for I (JFJ and PDM) and Se (JFJ).
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Affiliation(s)
- Elke Suess
- Institute of Biogeochemistry and Pollutant Dynamics , ETH Zurich , 8092 Zurich , Switzerland
- Eawag , Swiss Federal Institute of Aquatic Science and Technology , 8600 Duebendorf Switzerland
| | - Franziska Aemisegger
- Institute for Atmospheric and Climate Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Jeroen E Sonke
- Observatoire Midi-Pyrénées, CNRS-GET , Université de Toulouse , 31400 Toulouse , France
| | - Michael Sprenger
- Institute for Atmospheric and Climate Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Heini Wernli
- Institute for Atmospheric and Climate Science , ETH Zurich , 8092 Zurich , Switzerland
| | - Lenny H E Winkel
- Institute of Biogeochemistry and Pollutant Dynamics , ETH Zurich , 8092 Zurich , Switzerland
- Eawag , Swiss Federal Institute of Aquatic Science and Technology , 8600 Duebendorf Switzerland
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24
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Wu Y, Luo Z, Luo W, Ma T, Wang Y. Multiple isotope geochemistry and hydrochemical monitoring of karst water in a rapidly urbanized region. JOURNAL OF CONTAMINANT HYDROLOGY 2018; 218:44-58. [PMID: 30391046 DOI: 10.1016/j.jconhyd.2018.10.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 10/21/2018] [Accepted: 10/25/2018] [Indexed: 06/08/2023]
Abstract
Karst water is an important resource for drinking water supply. To determine the impacts of urbanization on karst water quality, we performed a case study in the rapidly urbanized Guiyang-Anshun region, Guizhou province, southwestern China. We interpret data from regional reconnaissance and long-term monitoring related to major ion chemistry, stable isotopes (Sr, C, S (for SO42-), and N and O (for NO3-)), remote sensing, and socio-economic development. We identify groundwater SO42- and NO3- sources by combined use of δ34S and Ca2+/Na+ molar ratio and δ15N and NO3-/Na+ ratio, respectively. We find that carbonate, sulfide, silicate, and gypsum weathering, anthropogenic inputs, and hydrodynamic conditions account for karst water composition and its seasonal variations. Atmospheric N and S deposition, nitrification of soil N, and sulfide oxidation control the background levels of groundwater NO3- and SO42-. The elevated concentrations of NO3- and SO42- at residential sites in rural and urban areas mainly arise from domestic sewage. Nitrification and fertilizer application are major reasons for the high levels of NO3- in regional groundwater systems. Vegetated/forested land area decreases as constructed land area increases, which results in declining biogenic CO2 production and inputs into the aquifer. Although the local government has attempted to control SO2 emissions, substantial increases in fossil fuel utilization and fertilizer consumption as well as population growth may have increased atmospheric HNO3 deposition and induced increasingly severe contamination of groundwater with NO3- and SO42-. Our results improve the understanding of urbanization impacts on water quality and are important for water resource management in karst regions.
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Affiliation(s)
- Ya Wu
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Zhaohui Luo
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China
| | - Wei Luo
- Guizhou Institute of Geo-Environment Monitoring, 550004 Guiyang, China
| | - Teng Ma
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
| | - Yanxin Wang
- School of Environmental Studies, China University of Geosciences, 430074 Wuhan, China.
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25
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Emmons AM, Bizimis M, Lang SQ, Stangler W, Geidel G, Baalousha M, Wanamaker E, Rothenberg SE. Enrichments of Metals, Including Methylmercury, in Sewage Spills in South Carolina, USA. JOURNAL OF ENVIRONMENTAL QUALITY 2018; 47:1258-1266. [PMID: 30272795 PMCID: PMC7372966 DOI: 10.2134/jeq2018.02.0067] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Exposure to microbial pathogens is the primary concern of sanitary sewer overflows; however, sewage spills may also be a significant source of toxic metals, including methylmercury (MeHg). Between November 2015 and January 2017, after Hurricane Joaquin, surface water samples were collected routinely from three creeks in Columbia, SC. Routine sampling coincided with six sewage spills. Total mercury (THg) and MeHg (unfiltered and filtered) and 32 other metals (filtered) were measured. Compared with surface water samples, THg (unfiltered and filtered), MeHg (unfiltered), and 19 other metals were significantly higher in sewage spills (all log-transformed) (two-tailed test, < 0.05 for all, = 38-42). Toxic weighting factors were applied to 18 metals, including THg and MeHg, in samples collected directly from sewage spills ( = 3-4) and a wastewater outfall ( = 5). On average, sewage was 18.2 and 12.0 times more toxic for THg and MeHg, respectively, and 1.75 times more toxic for all 18 metals, compared to treated effluent from the wastewater outfall. Results suggest sewage spills were a source of inorganic Hg, MeHg, and other metals to the receiving waters and may potentially contribute to water quality impairments.
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Affiliation(s)
- Alison M. Emmons
- School of the Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina, USA
| | - Michael Bizimis
- School of the Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina, USA
| | - Susan Q. Lang
- School of the Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina, USA
| | | | - Gwendelyn Geidel
- School of the Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina, USA
| | - Mohammed Baalousha
- Environmental Health Sciences, University of South Carolina, Columbia, South Carolina, USA
| | - Emma Wanamaker
- School of the Earth, Ocean, and Environment, University of South Carolina, Columbia, South Carolina, USA
| | - Sarah E. Rothenberg
- Environmental Health Sciences, University of South Carolina, Columbia, South Carolina, USA
- Present address: School of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon, USA
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26
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de Medeiros Engelmann P, Dos Santos VHJM, Barbieri CB, Augustin AH, Ketzer JMM, Rodrigues LF. Environmental monitoring of a landfill area through the application of carbon stable isotopes, chemical parameters and multivariate analysis. WASTE MANAGEMENT (NEW YORK, N.Y.) 2018; 76:591-605. [PMID: 29459205 DOI: 10.1016/j.wasman.2018.02.027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 02/08/2018] [Accepted: 02/13/2018] [Indexed: 06/08/2023]
Abstract
Leachate produced during an organic matter decomposition process has a complex composition and can cause contamination of surface and groundwaters adjacent to a landfill area. The monitoring of these areas is extremely important for the characterization of the leachate produced and to avoid or mitigate environmental damages. Thus, the present study has the objective of monitoring the area of a Brazilian landfill using conventional parameters (dissolved metals and anions in water) and alternative, stable carbon isotopes parameters (δ13C of dissolved organic and inorganic carbons in water) in addition to multivariate analysis techniques. The use of conventional and alternative parameters together with multivariate analysis showed that cells of the residues are at different phases of stabilization of the organic matter and probably already at C3 of the methanogenic phase of decomposition. In addition, the data showed that organic matter stabilization ponds present in the landfill are efficient and improve the quality of the leachate. Enrichment of the heavy 13C isotope in both surface and groundwater suggested contamination in two sampling sites.
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Affiliation(s)
- Pâmela de Medeiros Engelmann
- Institute of Petroleum and Natural Resources, Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga, 6681 - Building 96J, 90619-900 Porto Alegre, Brazil
| | - Victor Hugo Jacks Mendes Dos Santos
- Institute of Petroleum and Natural Resources, Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga, 6681 - Building 96J, 90619-900 Porto Alegre, Brazil
| | | | - Adolpho Herbert Augustin
- Institute of Petroleum and Natural Resources, Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga, 6681 - Building 96J, 90619-900 Porto Alegre, Brazil
| | - João Marcelo Medina Ketzer
- Institute of Petroleum and Natural Resources, Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga, 6681 - Building 96J, 90619-900 Porto Alegre, Brazil
| | - Luiz Frederico Rodrigues
- Institute of Petroleum and Natural Resources, Pontifical Catholic University of Rio Grande do Sul, Av. Ipiranga, 6681 - Building 96J, 90619-900 Porto Alegre, Brazil.
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27
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Engelhardt IC, Welty A, Blazewicz SJ, Bru D, Rouard N, Breuil MC, Gessler A, Galiano L, Miranda JC, Spor A, Barnard RL. Depth matters: effects of precipitation regime on soil microbial activity upon rewetting of a plant-soil system. ISME JOURNAL 2018; 12:1061-1071. [PMID: 29476139 DOI: 10.1038/s41396-018-0079-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/21/2017] [Accepted: 12/29/2017] [Indexed: 12/20/2022]
Abstract
Changes in frequency and amplitude of rain events, that is, precipitation patterns, result in different water conditions with soil depth, and likely affect plant growth and shape plant and soil microbial activity. Here, we used 18O stable isotope probing (SIP) to investigate bacterial and fungal communities that actively grew or not upon rewetting, at three different depths in soil mesocosms previously subjected to frequent or infrequent watering for 12 weeks (equal total water input). Phylogenetic marker genes for bacteria and fungi were sequenced after rewetting, and plant-soil microbial coupling documented by plant 13C-CO2 labeling. Soil depth, rather than precipitation pattern, was most influential in shaping microbial response to rewetting, and had differential effects on active and inactive bacterial and fungal communities. After rewetting, active bacterial communities were less rich, more even and phylogenetically related than the inactive, and reactivated throughout the soil profile. Active fungal communities after rewetting were less abundant and rich than the inactive. The coupling between plants and soil microbes decreased under infrequent watering in the top soil layer. We suggest that differences in fungal and bacterial abundance and relative activity could result in large effects on subsequent soil biogeochemical cycling.
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Affiliation(s)
- Ilonka C Engelhardt
- Agroécologie, INRA, AgroSup Dijon, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Amy Welty
- Agroécologie, INRA, AgroSup Dijon, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France.,Department of Plant Pathology and Microbiology, Iowa State University, Ames, IA, 50011, USA
| | - Steven J Blazewicz
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, USA
| | - David Bru
- Agroécologie, INRA, AgroSup Dijon, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Nadine Rouard
- Agroécologie, INRA, AgroSup Dijon, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Marie-Christine Breuil
- Agroécologie, INRA, AgroSup Dijon, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Arthur Gessler
- Swiss Federal Research Institute WSL, Zuercherstr. 111, 8903, Birmensdorf, Switzerland
| | - Lucía Galiano
- Swiss Federal Research Institute WSL, Zuercherstr. 111, 8903, Birmensdorf, Switzerland
| | - José Carlos Miranda
- Forest History, Physiology and Genetics Research Group, Universidad Politecnica de Madrid, Ciudad Universitaria s/n, 28040, Madrid, Spain
| | - Aymé Spor
- Agroécologie, INRA, AgroSup Dijon, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France
| | - Romain L Barnard
- Agroécologie, INRA, AgroSup Dijon, Univ. Bourgogne Franche-Comté, F-21000, Dijon, France.
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28
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Deeply-sourced formate fuels sulfate reducers but not methanogens at Lost City hydrothermal field. Sci Rep 2018; 8:755. [PMID: 29335466 PMCID: PMC5768773 DOI: 10.1038/s41598-017-19002-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 12/19/2017] [Indexed: 01/15/2023] Open
Abstract
Hydrogen produced during water-rock serpentinization reactions can drive the synthesis of organic compounds both biotically and abiotically. We investigated abiotic carbon production and microbial metabolic pathways at the high energy but low diversity serpentinite-hosted Lost City hydrothermal field. Compound-specific 14C data demonstrates that formate is mantle-derived and abiotic in some locations and has an additional, seawater-derived component in others. Lipids produced by the dominant member of the archaeal community, the Lost City Methanosarcinales, largely lack 14C, but metagenomic evidence suggests they cannot use formate for methanogenesis. Instead, sulfate-reducing bacteria may be the primary consumers of formate in Lost City chimneys. Paradoxically, the archaeal phylotype that numerically dominates the chimney microbial communities appears ill suited to live in pure hydrothermal fluids without the co-occurrence of organisms that can liberate CO2. Considering the lack of dissolved inorganic carbon in such systems, the ability to utilize formate may be a key trait for survival in pristine serpentinite-hosted environments.
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29
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Elevated moisture stimulates carbon loss from mineral soils by releasing protected organic matter. Nat Commun 2017; 8:1774. [PMID: 29176688 PMCID: PMC5701196 DOI: 10.1038/s41467-017-01998-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 10/30/2017] [Indexed: 11/17/2022] Open
Abstract
Moisture response functions for soil microbial carbon (C) mineralization remain a critical uncertainty for predicting ecosystem-climate feedbacks. Theory and models posit that C mineralization declines under elevated moisture and associated anaerobic conditions, leading to soil C accumulation. Yet, iron (Fe) reduction potentially releases protected C, providing an under-appreciated mechanism for C destabilization under elevated moisture. Here we incubate Mollisols from ecosystems under C3/C4 plant rotations at moisture levels at and above field capacity over 5 months. Increased moisture and anaerobiosis initially suppress soil C mineralization, consistent with theory. However, after 25 days, elevated moisture stimulates cumulative gaseous C-loss as CO2 and CH4 to >150% of the control. Stable C isotopes show that mineralization of older C3-derived C released following Fe reduction dominates C losses. Counter to theory, elevated moisture may significantly accelerate C losses from mineral soils over weeks to months—a critical mechanistic deficiency of current Earth system models. The effect of soil moisture on microbial activity and soil carbon storage remains unclear. Here, via Mollisol incubation experiments, the authors show elevated soil moisture can accelerate total carbon loss by facilitating microbial access to previously protected carbon, released following iron reduction.
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30
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Fractionation of Dissolved Organic Matter on Coupled Reversed-Phase Monolithic Columns and Characterisation Using Reversed-Phase Liquid Chromatography-High Resolution Mass Spectrometry. Chromatographia 2017. [DOI: 10.1007/s10337-017-3324-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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31
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Hagedorn F, Joseph J, Peter M, Luster J, Pritsch K, Geppert U, Kerner R, Molinier V, Egli S, Schaub M, Liu JF, Li M, Sever K, Weiler M, Siegwolf RTW, Gessler A, Arend M. Recovery of trees from drought depends on belowground sink control. NATURE PLANTS 2016; 2:16111. [PMID: 27428669 DOI: 10.1038/nplants.2016.111] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 06/20/2016] [Indexed: 05/21/2023]
Abstract
Climate projections predict higher precipitation variability with more frequent dry extremes(1). CO2 assimilation of forests decreases during drought, either by stomatal closure(2) or by direct environmental control of sink tissue activities(3). Ultimately, drought effects on forests depend on the ability of forests to recover, but the mechanisms controlling ecosystem resilience are uncertain(4). Here, we have investigated the effects of drought and drought release on the carbon balances in beech trees by combining CO2 flux measurements, metabolomics and (13)CO2 pulse labelling. During drought, net photosynthesis (AN), soil respiration (RS) and the allocation of recent assimilates below ground were reduced. Carbohydrates accumulated in metabolically resting roots but not in leaves, indicating sink control of the tree carbon balance. After drought release, RS recovered faster than AN and CO2 fluxes exceeded those in continuously watered trees for months. This stimulation was related to greater assimilate allocation to and metabolization in the rhizosphere. These findings show that trees prioritize the investment of assimilates below ground, probably to regain root functions after drought. We propose that root restoration plays a key role in ecosystem resilience to drought, in that the increased sink activity controls the recovery of carbon balances.
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Affiliation(s)
- Frank Hagedorn
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Jobin Joseph
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
- Chair of Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz, 79098 Freiburg, Germany
| | - Martina Peter
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Jörg Luster
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Karin Pritsch
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Centre for Environmental Health (GmbH), Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Uwe Geppert
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Centre for Environmental Health (GmbH), Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Rene Kerner
- Institute of Biochemical Plant Pathology, Helmholtz Zentrum München, German Research Centre for Environmental Health (GmbH), Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Virginie Molinier
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Simon Egli
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Marcus Schaub
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Jian-Feng Liu
- Research Institute of Forestry, Chinese Academy of Forestry, Xiangshan Road, 100091 Beijing, China
| | - Maihe Li
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
| | - Krunoslav Sever
- Department of Forest Genetics, Dendrology and Botany, Faculty of Forestry, University of Zagreb, Svetošimunska 25, HR-10000 Zagreb, Croatia
| | - Markus Weiler
- Chair of Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz, 79098 Freiburg, Germany
| | - Rolf T W Siegwolf
- Laboratory of Atmospheric Chemistry, Ecosystem Fluxes Group, Paul Scherrer Institute (PSI), 5232 Villigen, Switzerland
| | - Arthur Gessler
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
- Institute for Landscape Biogeochemistry, Leibnitz Centre for Agricultural Landscape Research (ZALF), Eberswalder Strasse 84, 15374 Müncheberg, Germany
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Altensteinstrasse 6, 14195 Berlin, Germany
| | - Matthias Arend
- Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903 Birmensdorf, Switzerland
- School of Forest Science and Resource Management, Technical University of Munich, Hans-Carl-von-Carlowitz-Platz 2, 85354 Freising, Germany
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Wiedemeier DB, Lang SQ, Gierga M, Abiven S, Bernasconi SM, Früh-Green GL, Hajdas I, Hanke UM, Hilf MD, McIntyre CP, Scheider MPW, Smittenberg RH, Wacker L, Wiesenberg GLB, Schmidt MWI. Characterization, Quantification and Compound-specific Isotopic Analysis of Pyrogenic Carbon Using Benzene Polycarboxylic Acids (BPCA). J Vis Exp 2016. [PMID: 27214064 PMCID: PMC4942176 DOI: 10.3791/53922] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Fire-derived, pyrogenic carbon (PyC), sometimes called black carbon (BC), is the carbonaceous solid residue of biomass and fossil fuel combustion, such as char and soot. PyC is ubiquitous in the environment due to its long persistence, and its abundance might even increase with the projected increase in global wildfire activity and the continued burning of fossil fuel. PyC is also increasingly produced from the industrial pyrolysis of organic wastes, which yields charred soil amendments (biochar). Moreover, the emergence of nanotechnology may also result in the release of PyC-like compounds to the environment. It is thus a high priority to reliably detect, characterize and quantify these charred materials in order to investigate their environmental properties and to understand their role in the carbon cycle. Here, we present the benzene polycarboxylic acid (BPCA) method, which allows the simultaneous assessment of PyC's characteristics, quantity and isotopic composition (13C and 14C) on a molecular level. The method is applicable to a very wide range of environmental sample materials and detects PyC over a broad range of the combustion continuum, i.e., it is sensitive to slightly charred biomass as well as high temperature chars and soot. The BPCA protocol presented here is simple to employ, highly reproducible, as well as easily extendable and modifiable to specific requirements. It thus provides a versatile tool for the investigation of PyC in various disciplines, ranging from archeology and environmental forensics to biochar and carbon cycling research.
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Affiliation(s)
| | - Susan Q Lang
- Department of Earth and Ocean Sciences, University of South Carolina
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Zhou Y, Guo H, Lu H, Mao R, Zheng H, Wang J. Analytical methods and application of stable isotopes in dissolved organic carbon and inorganic carbon in groundwater. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:1827-1835. [PMID: 26331934 DOI: 10.1002/rcm.7280] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Revised: 07/13/2015] [Accepted: 07/14/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE The stable isotopes of dissolved organic carbon (DOC) and inorganic carbon (DIC) provide insights into the carbon cycle, biogeochemical processes, and the fate of redox-sensitive elements in groundwater systems. The simultaneous determination of the stable isotope ratios (δ(13)C(DIC) and δ(13)C(DOC) values) in DIC and DOC in water samples would provide better understanding of those processes. METHODS The conditions for pretreating water samples prior to determining their DIC and DOC stable isotope ratios were optimized with a series of experiments on pre-purging (GasBench needle versus blowing concentrator) and reaction conditions. The carbon stable isotope ratios were determined by isotope ratio mass spectrometry. Sequential determination of the δ(13)C(DIC) and δ(13)C(DOC) values was also carried out using the optimized conditions. National Institute of Standards and Technology (NIST) δ(13)C standards were utilized to verify the precision of the proposed method. RESULTS The optimized pretreatment conditions for DIC isotope analysis involved pre-purging the empty sample bottle for 60 min using a pressurized helium gas-blowing concentrator and then reacting the sample with 85% H3PO4 for 60 min in a water bath at 60°C. The optimized pretreatment conditions for DOC isotope determination involved pre-purging the sample for 60 min with the pressurized helium gas-blowing concentrator after adding 0.1 mol L(-1) AgNO3 and 85% H3PO4 and then reacting with Na2S2O8 as an oxidant and AgNO3 as a catalyst, in a 100°C water bath for 60 min. CONCLUSIONS With the optimized methods, the analytical precision of the δ(13)C(DIC) and δ(13)C(DOC) values of the reference samples was 0.02‰. The precision of δ(13)C(DIC) and δ(13)C(DOC) values in groundwater samples was 0.03‰ and 0.17‰, respectively. For the sequential determination of the DIC and DOC carbon isotope ratios, the precision of the δ(13)C(DIC) and δ(13)C(DOC) values in reference samples was better than 0.2‰.
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Affiliation(s)
- Yinzhu Zhou
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Huaming Guo
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China
- School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing, 100083, China
| | - Hai Lu
- National Institute of Metrology, Beijing, 100013, China
| | - Ruoyu Mao
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China
| | - Hao Zheng
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, 100083, China
| | - Jun Wang
- National Institute of Metrology, Beijing, 100013, China
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Sandron S, Rojas A, Wilson R, Davies NW, Haddad PR, Shellie RA, Nesterenko PN, Kelleher BP, Paull B. Chromatographic methods for the isolation, separation and characterisation of dissolved organic matter. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2015; 17:1531-1567. [PMID: 26290053 DOI: 10.1039/c5em00223k] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
This review presents an overview of the separation techniques applied to the complex challenge of dissolved organic matter characterisation. The review discusses methods for isolation of dissolved organic matter from natural waters, and the range of separation techniques used to further fractionate this complex material. The review covers both liquid and gas chromatographic techniques, in their various modes, and electrophoretic based approaches. For each, the challenges that the separation and fractionation of such an immensely complex sample poses is critically reviewed.
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Affiliation(s)
- Sara Sandron
- Australian Centre for Research on Separation Sciences (ACROSS), University of Tasmania, Private Bag 75, Hobart, Tasmania, Australia 7001.
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Hotchkiss ER, Hall RO. Whole-stream13C tracer addition reveals distinct fates of newly fixed carbon. Ecology 2015; 96:403-16. [DOI: 10.1890/14-0631.1] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Xiong J, Li G, An T. Development of methodology for the determination of carbon isotope ratios using gas chromatography/combustion/isotope ratio mass spectrometry and applications in the biodegradation of phenolic brominated flame retardants and their degradation products. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:54-60. [PMID: 25462363 DOI: 10.1002/rcm.7072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 10/06/2014] [Accepted: 10/07/2014] [Indexed: 06/04/2023]
Abstract
RATIONALE Compound-specific stable carbon isotope analysis of phenolic brominated flame retardants (BFRs) and bisphenol A (BPA) has proven informative to discriminate their source and fate apportionment in the environment. However, because these compounds contain highly polar functional groups and exist as complex mixtures in environment matrices, derivatization is a necessary step, which adds additional non-analyte carbon atoms for analyses and may alter the original stable carbon isotope ratio. It is, therefore, imperative to gain an insight into the relationship between the δ(13) C values of the BFRs and BPA derivatives and those of underivatized BFRs and BPA. METHODS The δ(13) C values of BFRs and BPA N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) derivatives were measured by gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). The δ(13) C values of the BSTFA reagent and the standard underivatized BFRs and BPA were determined using elemental analyzer/isotope ratio mass spectrometry (EA/IRMS). The experimentally obtained δ(13) C values for BFRs and BPA derivatives were then compared with the theoretically calculated values. RESULTS The derivatization process introduces no isotopic fractionation for BFRs and BPA (the average difference between the theoretically calculated and experimentally obtained δ(13) C values was 0.06 ± 0.15‰, within the precision limits of the GC/C/IRMS measurements). Therefore, the δ(13) C values for the original underivatized BFRs and BPA were computed through a mass balance equation. CONCLUSIONS This work offers a novel tool to research the biotic or abiotic transformation processes of BFRs and BPA in the environment and will offer a perspective for the identification of the environmental source and fate of these organic compounds.
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Affiliation(s)
- Jukun Xiong
- State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environment Protection and Resource Utilization, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, China; University of Chinese Academy of Sciences, Beijing, 100049, China
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Levitt NP. Sample matrix effects on measured carbon and oxygen isotope ratios during continuous-flow isotope-ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2014; 28:2259-2274. [PMID: 25279739 DOI: 10.1002/rcm.7019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 08/08/2014] [Accepted: 08/12/2014] [Indexed: 06/03/2023]
Abstract
RATIONALE Continuous-flow isotope-ratio mass spectrometry (CF-IRMS) is frequently used to analyze CO2 found in media such as air, breath, and soil pore space gas with the aid of a sample preparation and transfer device such as a Gasbench II. This study investigated the effect that matrices other than helium (He) have on the measured δ(13)C and δ(18)O isotope ratios of CO2. METHODS Identical CO2 was added to sample vials with matrices of pure He, pure N2, or a 21:79 mixture of O2/N2 and analyzed by a ThermoFinnigan Delta(Plus) XP isotope-ratio mass spectrometer coupled to a ThermoFinnigan Gasbench II. Variables such as CO2 concentration, sample analysis sequence, and sample matrix removal ('blanking') through manipulation of an injection and dilution open split were tested to identify systematic isotope ratio offsets between the different matrix types. RESULTS The process of blanking induced a δ(13)C and δ(18)O offset of ≤0.2‰ between otherwise identical populations of CO2 samples in He. The (13)C/(12)C and (18)O/(16)O isotope ratios of CO2 sampled from pure N2 or a mixture of O2/N2 were found to be within 0.1 to 0.2‰ of those of an identical CO2 sampled from a He matrix when N2 or O2/N2 was removed prior to transport to the mass spectrometer. The measured oxygen isotope ratios of CO2 sampled from N2 and O2/N2 varied by as much as 0.6‰ and 4‰, respectively, if matrix gas was not removed prior to ionization. CONCLUSIONS Sampling CO2 from matrices similar to air does not significantly affect the measured (13)C/(12)C and (18)O/(16)O isotope ratios of CO2 when a gas-handling procedure that includes the removal of matrix gas is utilized. This procedure is much preferable to introducing matrix gas and potentially isobaric interference to the ion source.
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Affiliation(s)
- Nicholas Paul Levitt
- NASA Astrobiology Institute, Department of Earth and Environmental Sciences, University of Kentucky, 121 Washington Avenue, Lexington, KY, 40506, USA
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38
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Affiliation(s)
- K. E. Anders Ohlsson
- Department
of Forest Ecology and Management, Swedish University of Agricultural Sciences, SE-90183
Umeå, Sweden
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Malik A, Scheibe A, LokaBharathi PA, Gleixner G. Online stable isotope analysis of dissolved organic carbon size classes using size exclusion chromatography coupled to an isotope ratio mass spectrometer. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2012; 46:10123-10129. [PMID: 22861907 DOI: 10.1021/es302467y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Stable isotopic content of dissolved organic carbon (δ(13)C-DOC) provides valuable information on its origin and fate. In an attempt to get additional insights into DOC cycling, we developed a method for δ(13)C measurement of DOC size classes by coupling high-performance liquid chromatography (HPLC)-size exclusion chromatography (SEC) to online isotope ratio mass spectrometry (IRMS). This represents a significant methodological contribution to DOC research. The interface was evaluated using various organic compounds, thoroughly tested with soil-water from a C3-C4 vegetation change experiment, and also applied to riverine and marine DOC. δ(13)C analysis of standard compounds resulted in excellent analytical precision (≤0.3‰). Chromatography resolved soil DOC into 3 fractions: high molecular weight (HMW; 0.4-10 kDa), low molecular weight (LMW; 50-400 Da), and retained (R) fraction. Sample reproducibility for measurement of δ(13)C-DOC size classes was ±0.25‰ for HMW fraction, ± 0.54‰ for LMW fraction, and ±1.3‰ for R fraction. The greater variance in δ(13)C values of the latter fractions was due to their lower concentrations. The limit of quantification (SD ≤0.6‰) for each size fraction measured as a peak is 200 ng C (2 mg C/L). δ(13)C-DOC values obtained in SEC mode correlated significantly with those obtained without column in the μEA mode (p < 0.001, intercept 0.17‰), which rules out SEC-associated isotopic effects or DOC loss. In the vegetation change experiment, fractions revealed a clear trend in plant contribution to DOC; those in deeper soils and smaller size fractions had less plant material. It was also demonstrated that the technique can be successfully applied to marine and riverine DOC without further sample pretreatment.
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Affiliation(s)
- Ashish Malik
- Department of Biogeochemical Processes, Max Planck Institute for Biogeochemistry, Jena, Germany
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