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Du L, Luo Y, Zhang J, Shen Y, Zhang J, Tian R, Shao W, Xu Z. Reduction in precipitation amount, precipitation events, and nitrogen addition change ecosystem carbon fluxes differently in a semi-arid grassland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 927:172276. [PMID: 38583634 DOI: 10.1016/j.scitotenv.2024.172276] [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: 12/29/2023] [Revised: 04/04/2024] [Accepted: 04/04/2024] [Indexed: 04/09/2024]
Abstract
The increases in extent and frequency of extreme drought events and increased nitrogen (N) deposition due to global change are expected to have profound impacts on carbon cycling in semi-arid grasslands. However, how ecosystem CO2 exchange processes respond to different drought scenarios individually and interactively with N addition remains uncertain. In this study, we experimentally explored the effects of different drought scenarios (early season extreme drought, 50 % reduction in precipitation amount, and 50 % reduction in precipitation events) and N addition on net ecosystem CO2 exchange (NEE), ecosystem respiration (ER), and gross ecosystem productivity (GEP) over three growing seasons (2019-2021) in a semi-arid grassland in northern China. The growing-season ecosystem carbon fluxes in response to drought and N addition were influenced by inter-annual precipitation changes, with 2019 as a normal precipitation year, and 2020 and 2021 as wet years. Early season extreme drought stimulated NEE by reducing ER. 50 % reduction in precipitation amount decreased ER and GEP consistently in three years, but only significantly suppressed NEE in 2019. 50 % reduction in precipitation events stimulated NEE. Nitrogen addition stimulated NEE, ER, and GEP, but only significantly in wet years. The structural equation models showed that changes in carbon fluxes were regulated by soil moisture, soil temperature, microbial biomass nitrogen (MBN), and the key plant functional traits. Decreased community-weighted means of specific leaf area (CWMSLA) was closely related to the reduced ER and GEP under early season extreme drought and 50 % reduction in precipitation amount. While increased community-weighted means of plant height (CWMPH) largely accounted for the stimulated ER and GEP under 50 % reduction in precipitation events. Our study stresses the distinct effects of different drought scenarios and N enrichment on carbon fluxes, and highlights the importance of soil traits and the key plant traits in determining carbon exchange in this water-limited ecosystem.
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Affiliation(s)
- Lan Du
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Yonghong Luo
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Jiatao Zhang
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Yan Shen
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Jinbao Zhang
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Ru Tian
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Wenqian Shao
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China
| | - Zhuwen Xu
- Key Laboratory of Grassland Ecology, School of Ecology and Environment, Inner Mongolia University, Hohhot 010021, China.
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Kitz F, Wachter H, Spielmann F, Hammerle A, Wohlfahrt G. Root and rhizosphere contribution to the net soil COS exchange. PLANT AND SOIL 2023; 498:325-339. [PMID: 38665878 PMCID: PMC11039419 DOI: 10.1007/s11104-023-06438-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 12/02/2023] [Indexed: 04/28/2024]
Abstract
Background and aims Partitioning the measured net ecosystem carbon dioxide (CO2) exchange into gross primary productivity (GPP) and ecosystem respiration remains a challenge, which scientists try to tackle by using the properties of the trace gas carbonyl sulfide (COS). Its similar pathway into and within the leaf makes it a potential photosynthesis proxy. The application of COS as an effective proxy depends, among other things, on a robust inventory of potential COS sinks and sources within ecosystems. While the soil received some attention during the last couple of years, the role of plant roots is mostly unknown. In our study, we investigated the effects of live roots on the soil COS exchange. Methods An experimental setup was devised to measure the soil and the belowground plant parts of young beech trees observed over the course of 9 months. Results During the growing season, COS emissions were significantly lower when roots were present compared to chambers only containing soil, while prior to the growing season, with photosynthetically inactive trees, the presence of roots increased COS emissions. The difference in the COS flux between root-influenced and uninfluenced soil was fairly constant within each month, with diurnal variations in the COS flux driven primarily by soil temperature changes rather than the presence or absence of roots. Conclusion While the mechanisms by which roots influence the COS exchange are largely unknown, their contribution to the overall ground surface COS exchange should not be neglected when quantifying the soil COS exchange. Supplementary Information The online version contains supplementary material available at 10.1007/s11104-023-06438-0.
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Affiliation(s)
- Florian Kitz
- Universität Innsbruck, Institut für Ökologie, Sternwartestraße 15, Innsbruck, 6020 Austria
| | - Herbert Wachter
- Universität Innsbruck, Institut für Ökologie, Sternwartestraße 15, Innsbruck, 6020 Austria
| | - Felix Spielmann
- Universität Innsbruck, Institut für Ökologie, Sternwartestraße 15, Innsbruck, 6020 Austria
| | - Albin Hammerle
- Universität Innsbruck, Institut für Ökologie, Sternwartestraße 15, Innsbruck, 6020 Austria
| | - Georg Wohlfahrt
- Universität Innsbruck, Institut für Ökologie, Sternwartestraße 15, Innsbruck, 6020 Austria
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Belviso S, Lebegue B, Ramonet M, Kazan V, Pison I, Berchet A, Delmotte M, Yver-Kwok C, Montagne D, Ciais P. A top-down approach of sources and non-photosynthetic sinks of carbonyl sulfide from atmospheric measurements over multiple years in the Paris region (France). PLoS One 2020; 15:e0228419. [PMID: 32040521 PMCID: PMC7010246 DOI: 10.1371/journal.pone.0228419] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/14/2020] [Indexed: 11/18/2022] Open
Abstract
Carbonyl sulfide (COS) has been proposed as a proxy for carbon dioxide (CO2) taken up by plants at the leaf and ecosystem scales. However, several additional production and removal processes have been identified which could complicate its use at larger scales, among which are soil uptake, dark uptake by plants, and soil and anthropogenic emissions. This study evaluates the significance of these processes at the regional scale through a top-down approach based on atmospheric COS measurements at Gif-sur-Yvette (GIF), a suburban site near Paris (France). Over a period of four and a half years, hourly measurements at 7 m above ground level were performed by gas chromatography and combined with 222Radon measurements to calculate nocturnal COS fluxes using the Radon-Tracer Method. In addition, the vertical distribution of COS was investigated at a second site, 2 km away from GIF, where a fast gas analyzer deployed on a 100 m tower for several months during winter 2015-2016 recorded mixing ratios at 3 heights (15, 60 and 100 m). COS appears to be homogeneously distributed both horizontally and vertically in the sampling area. The main finding is that the area is a persistent COS sink even during wintertime episodes of strong pollution. Nighttime net uptake rates ranged from -1.5 to -32.8 pmol m-2 s-1, with an average of -7.3 ± 4.5 pmol m-2 s-1 (n = 253). However, episodes of biogenic emissions happened each year in June-July (11.9 ± 6.2 pmol m-2 s-1, n = 24). Preliminary analyses of simulated footprints of source areas influencing the recorded COS data suggest that long-range transport of COS from anthropogenic sources located in Benelux, Eastern France and Germany occasionally impacts the Paris area during wintertime. These production and removal processes may limit the use of COS to assess regional-scale CO2 uptake in Europe by plants through inverse modeling.
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Affiliation(s)
- Sauveur Belviso
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
- * E-mail:
| | - Benjamin Lebegue
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
| | - Michel Ramonet
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
| | - Victor Kazan
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
| | - Isabelle Pison
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
| | - Antoine Berchet
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
| | - Marc Delmotte
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
| | - Camille Yver-Kwok
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
| | - David Montagne
- UMR ECOSYS, INRA, AgroParisTech, Université Paris-Saclay, Thiverval-Grignon, France
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ- Université, Paris-Saclay, UMR8212, Gif-sur-Yvette, France
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4
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Jing W, Wang L, Li D, Bao X, Shi Y. Carbonyl sulfide (COS) and carbon disulfide (CS 2) exchange fluxes between cotton fields and the atmosphere in the arid area in Xinjiang, China. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2019; 41:2195-2207. [PMID: 30877628 DOI: 10.1007/s10653-019-00268-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 02/21/2019] [Indexed: 06/09/2023]
Abstract
Due to the important roles of carbonyl sulfide (COS) and carbon disulfide (CS2) in atmospheric chemistry, this study was designed to determine different proportions of COS and CS2 fluxes contributed from different sources, i.e., vegetation, soil and roots, at monthly and hourly timescales in the arid area in Xinjiang, China. Results indicated that the seasonal net uptake of COS by vegetation was predominant in the growing season. The CS2 fluxes from vegetation and soils had no significant seasonal variations compared with COS. The exchange rates of COS and CS2 have been found to be stimulated by the addition of nutrients in the form of urea fertilizer. Compared with the results of plots that were treated only with nitrogen, the treatments with both nitrogen and sulfur displayed no significant difference in the exchange fluxes. The results of compartment experiments indicated that the aboveground plants had the highest uptake of COS and had a vital role in the uptake of COS during the main growth period. The shares of COS emissions from the soil and roots increased to 6-17% and 55-58%, respectively, in the total COS fluxes when conditions, such as drought and senescence, were unfavorable for the developmental of vegetation. Observations of the preliminary diurnal fluxes indicated that the fluxes that occurred at night, with contributions from soils and plants, accounted for 27% of the total daily uptake of COS uptake. These quantitative results may be reasonably accounted for the use of COS as a promising tracer to obtain independent constraints on terrestrial carbon exchange at regional to global scales for their response to special environmental conditions in semiarid area.
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Affiliation(s)
- Weiwen Jing
- Applied Chemistry Laboratory, College of Chemical Engineering, Xinjiang Agricultural University, Ürümqi, 830052, Xinjiang Uygur Autonomous Region, People's Republic of China.
| | - Liling Wang
- Applied Chemistry Laboratory, College of Chemical Engineering, Xinjiang Agricultural University, Ürümqi, 830052, Xinjiang Uygur Autonomous Region, People's Republic of China
| | - Deqiang Li
- Applied Chemistry Laboratory, College of Chemical Engineering, Xinjiang Agricultural University, Ürümqi, 830052, Xinjiang Uygur Autonomous Region, People's Republic of China
| | - Xiaowei Bao
- College of Food and Pharmaceutical Sciences, Xinjiang Agricultural University, Ürümqi, 830052, Xinjiang Uygur Autonomous Region, People's Republic of China
| | - Yingshuang Shi
- Applied Chemistry Laboratory, College of Chemical Engineering, Xinjiang Agricultural University, Ürümqi, 830052, Xinjiang Uygur Autonomous Region, People's Republic of China
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Spielmann FM, Wohlfahrt G, Hammerle A, Kitz F, Migliavacca M, Alberti G, Ibrom A, El‐Madany TS, Gerdel K, Moreno G, Kolle O, Karl T, Peressotti A, Delle Vedove G. Gross Primary Productivity of Four European Ecosystems Constrained by Joint CO 2 and COS Flux Measurements. GEOPHYSICAL RESEARCH LETTERS 2019; 46:5284-5293. [PMID: 31423034 PMCID: PMC6686783 DOI: 10.1029/2019gl082006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/25/2019] [Accepted: 04/29/2019] [Indexed: 06/10/2023]
Abstract
Gross primary productivity (GPP), the gross uptake of carbon dioxide (CO2) by plant photosynthesis, is the primary driver of the land carbon sink, which presently removes around one quarter of the anthropogenic CO2 emissions each year. GPP, however, cannot be measured directly and the resulting uncertainty undermines our ability to project the magnitude of the future land carbon sink. Carbonyl sulfide (COS) has been proposed as an independent proxy for GPP as it diffuses into leaves in a fashion very similar to CO2, but in contrast to the latter is generally not emitted. Here we use concurrent ecosystem-scale flux measurements of CO2 and COS at four European biomes for a joint constraint on CO2 flux partitioning. The resulting GPP estimates generally agree with classical approaches relying exclusively on CO2 fluxes but indicate a systematic underestimation under low light conditions, demonstrating the importance of using multiple approaches for constraining present-day GPP.
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Affiliation(s)
- F. M. Spielmann
- Department of EcologyUniversity of InnsbruckInnsbruckAustria
| | - G. Wohlfahrt
- Department of EcologyUniversity of InnsbruckInnsbruckAustria
| | - A. Hammerle
- Department of EcologyUniversity of InnsbruckInnsbruckAustria
| | - F. Kitz
- Department of EcologyUniversity of InnsbruckInnsbruckAustria
| | - M. Migliavacca
- Department of Biogeochemical IntegrationMax Planck Institute for BiogeochemistryJenaGermany
| | - G. Alberti
- Department of Agricultural, Food, Environmental and Animal SciencesUniversity of UdineUdineItaly
- CNR‐IBIMETFirenzeItaly
| | - A. Ibrom
- Department of Environmental EngineeringTechnical University of DenmarkKongens LyngbyDenmark
| | - T. S. El‐Madany
- Department of Biogeochemical IntegrationMax Planck Institute for BiogeochemistryJenaGermany
| | - K. Gerdel
- Department of EcologyUniversity of InnsbruckInnsbruckAustria
| | - G. Moreno
- INDEHESA‐Forest Research GroupUniversidad de ExtremaduraPlasenciaSpain
| | - O. Kolle
- Department of Biogeochemical IntegrationMax Planck Institute for BiogeochemistryJenaGermany
| | - T. Karl
- Institute of Atmospheric and Cryospheric SciencesUniversity of InnsbruckInnsbruckAustria
| | - A. Peressotti
- Department of Agricultural, Food, Environmental and Animal SciencesUniversity of UdineUdineItaly
| | - G. Delle Vedove
- Department of Agricultural, Food, Environmental and Animal SciencesUniversity of UdineUdineItaly
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Kitz F, Gómez-Brandón M, Eder B, Etemadi M, Spielmann FM, Hammerle A, Insam H, Wohlfahrt G. Soil carbonyl sulfide exchange in relation to microbial community composition: insights from a managed grassland soil amendment experiment. SOIL BIOLOGY & BIOCHEMISTRY 2019; 135:28-37. [PMID: 31579268 PMCID: PMC6774760 DOI: 10.1016/j.soilbio.2019.04.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The viability of carbonyl sulfide (COS) measurements for partitioning ecosystem-scale net carbon dioxide (CO2) fluxes into photosynthesis and respiration critically depends on our knowledge of non-leaf sinks and sources of COS in ecosystems. We combined soil gas exchange measurements of COS and CO2 with next-generation sequencing technology (NGS) to investigate the role of soil microbiota for soil COS exchange. We applied different treatments (litter and glucose addition, enzyme inhibition and gamma sterilization) to soil samples from a temperate grassland to manipulate microbial composition and activity. While untreated soil was characterized by consistent COS uptake, other treatments reduced COS uptake and even turned the soil into a net COS source. Removing biotic processes through sterilization led to positive or zero fluxes. We used NGS to link changes in the COS response to alterations in the microbial community composition, with bacterial data having a higher explanatory power for the measured COS fluxes than fungal data. We found that the genera Arthrobacter and Streptomyces were particularly abundant in samples exhibiting high COS emissions. Our results indicate co-occurring abiotic production and biotic consumption of COS in untreated soil, the latter linked to carbonic anhydrase activity, and a strong dependency of the COS flux on the activity, identity, abundance of and substrate available to microorganisms.
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Affiliation(s)
- Florian Kitz
- Department of Ecology, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - María Gómez-Brandón
- Department of Microbiology, University of Innsbruck, Technikerstraße 25, Innsbruck, Austria
| | - Bernhard Eder
- Department of Microbiology, University of Innsbruck, Technikerstraße 25, Innsbruck, Austria
| | - Mohammad Etemadi
- Department of Microbiology, University of Innsbruck, Technikerstraße 25, Innsbruck, Austria
| | - Felix M. Spielmann
- Department of Ecology, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Albin Hammerle
- Department of Ecology, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Heribert Insam
- Department of Microbiology, University of Innsbruck, Technikerstraße 25, Innsbruck, Austria
| | - Georg Wohlfahrt
- Department of Ecology, University of Innsbruck, Sternwartestraße 15, Innsbruck, Austria
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Nitrogen Fertilization Reduces the Capacity of Soils to Take up Atmospheric Carbonyl Sulphide. SOIL SYSTEMS 2018. [DOI: 10.3390/soilsystems2040062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Soils are an important carbonyl sulphide (COS) sink. However, they can also act as sources of COS to the atmosphere. Here we demonstrate that variability in the soil COS sink and source strength is strongly linked to the available soil inorganic nitrogen (N) content across a diverse range of biomes in Europe. We revealed in controlled laboratory experiments that a one-off addition of ammonium nitrate systematically decreased the COS uptake rate whilst simultaneously increasing the COS production rate of soils from boreal and temperate sites in Europe. Furthermore, we found strong links between variations in the two gross COS fluxes, microbial biomass, and nitrate and ammonium contents, providing new insights into the mechanisms involved. Our findings provide evidence for how the soil–atmosphere exchange of COS is likely to vary spatially and temporally, a necessary step for constraining the role of soils and land use in the COS mass budget.
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Yang F, Qubaja R, Tatarinov F, Rotenberg E, Yakir D. Assessing canopy performance using carbonyl sulfide measurements. GLOBAL CHANGE BIOLOGY 2018; 24:3486-3498. [PMID: 29575496 DOI: 10.1111/gcb.14145] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 02/16/2018] [Indexed: 06/08/2023]
Abstract
Carbonyl sulfide (COS) is a tracer of ecosystem photosynthesis that can advance carbon cycle research from leaf to global scales; however, a range of newly reported caveats related to sink/source strength of various ecosystem components hinder its application. Using comprehensive eddy-covariance and chamber measurements, we systematically measure ecosystem contributions from leaf, stem, soil, and litter and were able to close the ecosystem COS budget. The relative contributions of nonphotosynthetic components to the overall canopy-scale flux are relatively small (~4% during peak activity season) and can be independently estimated based on their responses to temperature and humidity. Converting COS to photosynthetic CO2 fluxes based on the leaf relative uptake of COS/CO2 , faces challenges due to observed daily and seasonal changes. Yet, this ratio converges around a constant value (~1.6), and the variations, dominated by light intensity, were found unimportant on a flux-weighted daily time-scale, indicating a mean ratio of daytime gross-to-net primary productivity of ~2 in our ecosystem. The seasonal changes in the leaf relative uptake ratio may indicate a reduction in mesophyll conductance in winter, and COS-derived canopy conductance permitted canopy temperature estimate consistent with radiative skin temperature. These results support the feasibility of using COS as a powerful and much-needed means of assessing ecosystem function and its response to change.
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Affiliation(s)
- Fulin Yang
- Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Rafat Qubaja
- Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Fyodor Tatarinov
- Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Eyal Rotenberg
- Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
| | - Dan Yakir
- Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel
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9
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Coupled Biological and Abiotic Mechanisms Driving Carbonyl Sulfide Production in Soils. SOIL SYSTEMS 2018. [DOI: 10.3390/soilsystems2030037] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Gerdel K, Spielmann FM, Hammerle A, Wohlfahrt G. Eddy covariance carbonyl sulphide flux measurements with a quantum cascade laser absorption spectrometer. ATMOSPHERIC MEASUREMENT TECHNIQUES 2017; 10:3525-3537. [PMID: 29093762 PMCID: PMC5662146 DOI: 10.5194/amt-10-3525-2017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The trace gas carbonyl sulphide (COS) has lately received growing interest in the eddy covariance (EC) community due to its potential to serve as an independent approach for constraining gross primary production and canopy stomatal conductance. Thanks to recent developments of fast-response high-precision trace gas analysers (e.g. quantum cascade laser absorption spectrometers (QCLAS)), a handful of EC COS flux measurements have been published since 2013. To date, however, a thorough methodological characterisation of QCLAS with regard to the requirements of the EC technique and the necessary processing steps has not been conducted. The objective of this study is to present a detailed characterization of the COS measurement with the Aerodyne QCLAS in the context of the EC technique, and to recommend best EC processing practices for those measurements. Data were collected from May to October 2015 at a temperate mountain grassland in Tyrol, Austria. Analysis of the Allan variance of high-frequency concentration measurements revealed sensor drift to occur under field conditions after an averaging time of around 50 s. We thus explored the use of two high-pass filtering approaches (linear detrending and recursive filtering) as opposed to block averaging and linear interpolation of regular background measurements for covariance computation. Experimental low-pass filtering correction factors were derived from a detailed cospectral analysis. The CO2 and H2O flux measurements obtained with the QCLAS were compared against those obtained with a closed-path infrared gas analyser. Overall, our results suggest small, but systematic differences between the various high-pass filtering scenarios with regard to the fraction of data retained in the quality control and flux magnitudes. When COS and CO2 fluxes are combined in the so-called ecosystem relative uptake rate, systematic differences between the high-pass filtering scenarios largely cancel out, suggesting that this relative metric represents a robust key parameter comparable between studies relying on different post-processing schemes.
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Affiliation(s)
- Katharina Gerdel
- Institut of Ecology, University of Innsbruck, Innsbruck, Austria
| | | | - Albin Hammerle
- Institut of Ecology, University of Innsbruck, Innsbruck, Austria
| | - Georg Wohlfahrt
- Institut of Ecology, University of Innsbruck, Innsbruck, Austria
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Wohlfahrt G. Bi-directional COS exchange in bryophytes challenges its use as a tracer for gross primary productivity. THE NEW PHYTOLOGIST 2017; 215:923-925. [PMID: 28695681 PMCID: PMC5657470 DOI: 10.1111/nph.14658] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Affiliation(s)
- Georg Wohlfahrt
- Institut für Ökologie, Universität Innsbruck, Sternwartestr. 15, 6020, Innsbruck, Austria
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