Dianming Wu
Max Planck Society
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Featured researches published by Dianming Wu.
Science | 2013
Robert Oswald; Thomas Behrendt; M. Ermel; Dianming Wu; Hang Su; Yafang Cheng; Claudia Breuninger; Alexander Moravek; E. Mougin; C. Delon; Benjamin Loubet; Andreas Pommerening-Röser; Matthias Sörgel; Ulrich Pöschl; Thorsten Hoffmann; Meinrat O. Andreae; F. X. Meixner; Ivonne Trebs
From Soil to Sky Trace gases emitted either through the activity of microbial communities or from abiotic reactions in the soil influence atmospheric chemistry. In laboratory column experiments using several soil types, Oswald et al. (p. 1233) showed that soils from arid regions and farmlands can produce substantial quantities of nitric oxide (NO) and nitrous acid (HONO). Ammonia-oxidizing bacteria are the primary source of HONO at comparable levels to NO, thus serving as an important source of reactive nitrogen to the atmosphere. HONO emissions from soil are comparable to those of NO in arid and arable regions. Abiotic release of nitrous acid (HONO) in equilibrium with soil nitrite (NO2–) was suggested as an important contributor to the missing source of atmospheric HONO and hydroxyl radicals (OH). The role of total soil-derived HONO in the biogeochemical and atmospheric nitrogen cycles, however, has remained unknown. In laboratory experiments, we found that for nonacidic soils from arid and arable areas, reactive nitrogen emitted as HONO is comparable with emissions of nitric oxide (NO). We show that ammonia-oxidizing bacteria can directly release HONO in quantities larger than expected from the acid-base and Henry’s law equilibria of the aqueous phase in soil. This component of the nitrogen cycle constitutes an additional loss term for fixed nitrogen in soils and a source for reactive nitrogen in the atmosphere.
Proceedings of the National Academy of Sciences of the United States of America | 2015
Bettina Weber; Dianming Wu; Alexandra Tamm; Nina Ruckteschler; Emilio Rodríguez-Caballero; Jörg Steinkamp; Hannah Meusel; Wolfgang Elbert; Thomas Behrendt; Matthias Sörgel; Yafang Cheng; Paul J. Crutzen; Hang Su; Ulrich Pöschl
Significance Biological soil crusts (biocrusts), occurring on ground surfaces in drylands throughout the world, are among the oldest life forms consisting of cyanobacteria, lichens, mosses, and algae plus heterotrophic organisms in varying proportions. They prevent soil erosion and nurture ecosystems by fixing carbon and nitrogen from the atmosphere. Here, we show that the fixed nitrogen is processed within the biocrusts, and during this metabolic activity, nitrogen oxide and nitrous acid are released to the atmosphere. Both of these gases are highly relevant, as they influence the radical formation and oxidizing capacity of the lower atmosphere, also interacting with climate change. In drylands, biocrusts appear to play a key role both in nitrogen fixation and the release of atmospheric reactive nitrogen. Reactive nitrogen species have a strong influence on atmospheric chemistry and climate, tightly coupling the Earth’s nitrogen cycle with microbial activity in the biosphere. Their sources, however, are not well constrained, especially in dryland regions accounting for a major fraction of the global land surface. Here, we show that biological soil crusts (biocrusts) are emitters of nitric oxide (NO) and nitrous acid (HONO). Largest fluxes are obtained by dark cyanobacteria-dominated biocrusts, being ∼20 times higher than those of neighboring uncrusted soils. Based on laboratory, field, and satellite measurement data, we obtain a best estimate of ∼1.7 Tg per year for the global emission of reactive nitrogen from biocrusts (1.1 Tg a−1 of NO-N and 0.6 Tg a−1 of HONO-N), corresponding to ∼20% of global nitrogen oxide emissions from soils under natural vegetation. On continental scales, emissions are highest in Africa and South America and lowest in Europe. Our results suggest that dryland emissions of reactive nitrogen are largely driven by biocrusts rather than the underlying soil. They help to explain enigmatic discrepancies between measurement and modeling approaches of global reactive nitrogen emissions. As the emissions of biocrusts strongly depend on precipitation events, climate change affecting the distribution and frequency of precipitation may have a strong impact on terrestrial emissions of reactive nitrogen and related climate feedback effects. Because biocrusts also account for a large fraction of global terrestrial biological nitrogen fixation, their impacts should be further quantified and included in regional and global models of air chemistry, biogeochemistry, and climate.
Nutrient Cycling in Agroecosystems | 2012
Wenxu Dong; Chunsheng Hu; Yuming Zhang; Dianming Wu
No-tillage cropping can increase soil carbon (C) stocks and aggregation, and subsequently impact the internal nitrogen (N) cycle and gas loss. The 15N pool dilution method was used to study gross N transformations, and relative proportions of nitrous oxide (N2O) emissions derived from denitrification versus nitrification-related processes under long-term tillage systems (no-tillage, rotary tillage and conventional tillage) in the North China Plain. In-field incubation experiments were repeated in successive growing seasons during April–November in 2007. Gross mineralization rates for rotary and mouldboard plough tillage (3.6xa0±xa00.3–10.6xa0±xa01.5xa0mgxa0Nxa0kg−1xa0days−1) were significantly higher than for no-tillage (1.7xa0±xa00.8–6.8xa0±xa01.1xa0mgxa0Nxa0kg−1xa0days−1). Gross mineralization was positively correlated with soil moisture and temperature, as well as with microbial biomass N and C. However, there was no consistent tillage effect on gross nitrification, and gross nitrification was positively correlated with soil moisture, but not with gross mineralization and microbial biomass. N2O emissions were higher in no-tillage (NT) than for conventional tillage (CT) during May–August. The 15N labelling indicated that 26–92xa0% of the N2O was directly derived from the soil ammonium (NH4+) pool. Emission rates of N2O from both nitrification and denitrification were positively correlated with NH4+ supply as expressed by gross mineralization, but not correlated with supply of nitrate as expressed by gross nitrification. The fraction of nitrified N emitted as N2O was positively correlated with changes in soil moisture and varied within 0.01–2.51xa0‰. Our results showed that the tillage management impact on gross N transformation was not consistent with N2O emission, and more detailed information on the controls over N2O formation needs to be sought.
Environmental Science & Technology | 2014
Dianming Wu; Christopher J. Kampf; Ulrich Pöschl; Robert Oswald; Junfang Cui; Michael Ermel; Chunsheng Hu; Ivonne Trebs; Matthias Sörgel
Gaseous nitrous acid (HONO), the protonated form of nitrite, contributes up to ∼60% to the primary formation of hydroxyl radical (OH), which is a key oxidant in the degradation of most air pollutants. Field measurements and modeling studies indicate a large unknown source of HONO during daytime. Here, we developed a new tracer method based on gas-phase stripping-derivatization coupled to liquid chromatography-mass spectrometry (LC-MS) to measure the 15N relative exceedance, ψ(15N), of HONO in the gas-phase. Gaseous HONO is quantitatively collected and transferred to an azo dye, purified by solid phase extraction (SPE), and analyzed using high performance liquid chromatography coupled to mass spectrometry (HPLC-MS). In the optimal working range of ψ(15N)=0.2-0.5, the relative standard deviation of ψ(15N) is <4%. The optimum pH and solvents for extraction by SPE and potential interferences are discussed. The method was applied to measure HO15NO emissions from soil in a dynamic chamber with and without spiking 15) labeled urea. The identification of HO15NO from soil with 15N urea addition confirmed biogenic emissions of HONO from soil. The method enables a new approach of studying the formation pathways of HONO and its role for atmospheric chemistry (e.g., ozone formation) and environmental tracer studies on the formation and conversion of gaseous HONO or aqueous NO2- as part of the biogeochemical nitrogen cycle, e.g., in the investigation of fertilization effects on soil HONO emissions and microbiological conversion of NO2- in the hydrosphere.
The ISME Journal | 2018
Stefanie Maier; Alexandra Tamm; Dianming Wu; Jennifer Caesar; Martin Grube; Bettina Weber
Biological soil crusts (biocrusts) cover about 12% of the Earth’s land masses, thereby providing ecosystem services and affecting biogeochemical fluxes on a global scale. They comprise photoautotrophic cyanobacteria, algae, lichens and mosses, which grow together with heterotrophic microorganisms, forming a model system to study facilitative interactions and assembly principles in natural communities. Biocrusts can be classified into cyanobacteria-, lichen-, and bryophyte-dominated types, which reflect stages of ecological succession. In this study, we examined whether these categories include a shift in heterotrophic communities and whether this may be linked to altered physiological properties. We analyzed the microbial community composition by means of qPCR and high-throughput amplicon sequencing and utilized flux measurements to investigate their physiological properties. Our results revealed that once 16S and 18S rRNA gene copy numbers increase, fungi become more predominant and alpha diversity increases with progressing succession. Bacterial communities differed significantly between biocrust types with a shift from more generalized to specialized organisms along succession. CO2 gas exchange measurements revealed large respiration rates of late successional crusts being significantly higher than those of initial biocrusts, and different successional stages showed distinct NO and HONO emission patterns. Thus, our study suggests that the photoautotrophic organisms facilitate specific microbial communities, which themselves strongly influence the overall physiological properties of biocrusts and hence local to global nutrient cycles.
Scientific Reports | 2018
M. Ermel; Thomas Behrendt; Robert Oswald; Bettina Derstroff; Dianming Wu; S. Hohlmann; Christof Stönner; Andreas Pommerening-Röser; M. Könneke; J. Williams; F. X. Meixner; Meinrat O. Andreae; Ivonne Trebs; Matthias Sörgel
Nitrous acid (HONO) is an important precursor of the hydroxyl radical (OH), the atmosphere´s primary oxidant. An unknown strong daytime source of HONO is required to explain measurements in ambient air. Emissions from soils are one of the potential sources. Ammonia-oxidizing bacteria (AOB) have been identified as possible producers of these HONO soil emissions. However, the mechanisms for production and release of HONO in soils are not fully understood. In this study, we used a dynamic soil-chamber system to provide direct evidence that gaseous emissions from nitrifying pure cultures contain hydroxylamine (NH2OH), which is subsequently converted to HONO in a heterogeneous reaction with water vapor on glass bead surfaces. In addition to different AOB species, we found release of HONO also in ammonia-oxidizing archaea (AOA), suggesting that these globally abundant microbes may also contribute to the formation of atmospheric HONO and consequently OH. Since biogenic NH2OH is formed by diverse organisms, such as AOB, AOA, methane-oxidizing bacteria, heterotrophic nitrifiers, and fungi, we argue that HONO emission from soil is not restricted to the nitrifying bacteria, but is also promoted by nitrifying members of the domains Archaea and Eukarya.
Plant and Soil | 2017
Dengzhou Gao; Xiaofei Li; Xianbiao Lin; Dianming Wu; Baoshi Jin; Yanping Huang; Min Liu; Xing Chen
AimsThe invasion of Spartina alterniflora has a significant influence on soil biogeochemistry cycling in coastal wetlands. However, the roles of the S. alterniflora invasion chronosequence in regulating soil dissimilatory NO3− reduction processes (denitrification (DNF), anaerobic ammonium oxidation (ANA) and dissimilatory nitrate reduction to ammonium (DNRA)) remains unclear. The objective of this study was therefore to reveal the effects of S. alterniflora invasion on the soil NO3− reduction processes and associated gene abundance.MethodsWe investigated plant biomass, soil properties, NO3− reduction processes and associated gene abundance of NO3− reduction pathways following S. alterniflora invasion chronosequences of 6, 10, and 14xa0years compared to Cyperus malaccensis in a coastal wetland of southeastern China.ResultsThe S. alterniflora invasion generally increased plant biomass, soil water content, available substrates, nirS, anammox bacterial 16S rRNA and nrfA gene abundance, but it decreased soil bulk density. Soil DNF, ANA and DNRA rates in stands of S. alterniflora ranged from 1.52 to 17.58, 0.31 to 1.27 and 0.14 to 2.01xa0nmol N g−1xa0h−1, respectively, which were generally higher than the values in stands of C. malaccensis. The soil NO3− reduction rates generally increased with the increasing chronosequence of invasion by S. alterniflora, while the changes in DNF and ANA rates were less pronounced than changes in DNRA. DNF was the dominant pathway (70.00–92.41%), and the ANA and DNRA contributed 2.49–15.27% and 5.10–20.75% to the total NO3− reduction, respectively. The contributions of DNF and ANA to the total NO3− reduction decreased slightly, while the contribution of DNRA increased remarkably after S. alterniflora invasion. Soil NO3− reduction processes were influenced by available substrates and associated microbial activities. It is estimated that an N loss of approximately 520.97xa0g N m−2xa0yr.−1 in C. malaccensis and 794.46xa0g N m−2xa0yr.−1 in S. alterniflora were linked to both DNF and ANA processes.ConclusionsThe S. alterniflora invasion altered soil NO3− reduction processes by increasing soil microbial activities and available substrates and thus may further mediate the soil N availability in the coastal wetlands.
Soil Biology & Biochemistry | 2013
Dianming Wu; Wenxu Dong; O. Oenema; Yuying Wang; Ivonne Trebs; Chunsheng Hu
Atmospheric Chemistry and Physics | 2015
Matthias Sörgel; Ivonne Trebs; Dianming Wu; Andreas Held
Atmospheric Chemistry and Physics | 2017
Hannah Meusel; Alexandra Tamm; U. Kuhn; Dianming Wu; Anna Lena Leifke; Sabine Fiedler; Nina Ruckteschler; Petya Yordanova; Naama Lang-Yona; Mira L. Pöhlker; J. Lelieveld; Thorsten Hoffmann; Ulrich Pöschl; Hang Su; Bettina Weber; Yafang Cheng