Effects of elevated CO2 on nitrogen cycling in soil and alfalfa leaves

Increased atmospheric CO2 concentration will have an significant impact on the nitrogen cycle of terrestrial ecosystems. The elevation of atmospheric CO2 has become an inevitable trend, and nitrogen is the most important factor affecting plant growth. But it is rare to explore the effect of CO2 on nitrogen cycle by measuring the value of &#948;15N. The &#948;15N value as a comprehensive indicator of the nitrogen cycle of the ecosystem, which can not only clarify the migration and transformation of nitrogen, but also effectively indicate the nitrogen limit and nitrogen open level of the ecosystem. Our experiment selected alfalfa (C3 plant) as the research object, then investigated the response of nitrate nitrogen, ammonia nitrogen and absorbable nitrogen to the elevated CO2 concentration in soil and alfalfa leaves under ambient and elevated atmospheric CO2 (500 and 700ppm) in open top chambers. The 15N isotope value was determined by bacterial denitrification , and 15N-gas chromatography (GC-MS) were applied to further analyze the effect of elevated CO2 concentration on nitrogen cycling in soil and plant leaves. The increase of CO2 concentration led to the decline of various inorganic nitrogen levels in soil, and the &#948;15N in the soil also showed a certain downward trend, but always maintained a positive value. The nitrogen level and &#948;15N values in alfalfa leaves did not change significantly, showing a small increase. It indicates that there are different degrees of nitrogen loss in the leaves under the influence of different concentrations of CO2. These results are closely related to the fractional distillation of nitrogen isotopes caused by microorganisms in the process of nitrogen morphologic transformation. We briefly reviewed the changes of nitrogen content in soil and plant leaves under elevated CO2, providing new insights into the nitrogen cycle of soils and plants under high CO2 concentrations. It also provides a scientific basis for the protection of soil and plants under the greenhouse effect.

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Faculty Opinions recommendation of Controls on nitrogen cycling in terrestrial ecosystems: a synthetic analysis of literature data.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1032440.323939 ◽

2005 ◽

Author(s):

Adrien Finzi

Keyword(s):

Nitrogen Cycling ◽

Terrestrial Ecosystems

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Combined organic carbon and complete nitrogen removal using anaerobic and aerobic upflow filters

Water Science & Technology ◽

10.2166/wst.1994.0629 ◽

1994 ◽

Vol 30 (12) ◽

pp. 297-306 ◽

Cited By ~ 31

Author(s):

Joseph Akunna ◽

Claude Bizeau ◽

René Moletta ◽

Nicolas Bernet ◽

Alain Héduit

Keyword(s):

Organic Carbon ◽

Removal Efficiency ◽

Nitrogen Removal ◽

Nitrogen Loss ◽

Ammonia Nitrogen ◽

Cod Removal ◽

Cod Removal Efficiency ◽

Treated Effluent ◽

Treated Effluents ◽

Aerobic And Anaerobic

Two laboratory upflow aerobic and anaerobic filters fed with synthetic wastewaters were used to study firstly the effects of aeration rate on the nitrification of anaerobically pre-treated effluents and secondly the effects of recycle-to-influent ratios on methane production rate, denitrification and nitrification performances of a combined aerobic and anaerobic wastewater treatment process. Nitrification of anaerobically pre-treated effluent was accompanied by aerobic post-treatment for residual COD removal. A comparison of nitrification performances using autotrophic medium and anaerobically pre-treated effluents (containing 1203 mg COD 1−1) with the same ammonia nitrogen concentration of about 300 mg NH4-N 1−1 showed that 3% of added ammonia nitrogen was assimilated by autotrophic nitrifiers during nitrification of the autotrophic medium while up to 30% was assimilated by both nitrifiers and heterotrophs during organic carbon removal and nitrification of anaerobically pre-treated effluent. Furthermore, it was suspected that significant nitrogen loss through denitrification occured in the aerobic filter especially at low aeration rates. In the study of the combined aerobic-anaerobic system, maximum ammonia nitrogen removal of 70% through denitrification was obtained at recycle-to-influent ratios of 4 and 5. COD removal efficiency in the anaerobic filter decreased from 77 to 60% for recycle-to-influent ratios of zero to 5. Overall COD removal efficiency of the entire system was constant at about 99% due to heterotrophic COD removal in the aerobic filter.

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Short-term effects of nereid polychaete size and density on sediment inorganic nitrogen cycling under varying oxygen conditions

Marine Ecology Progress Series ◽

10.3354/meps11185 ◽

2015 ◽

Vol 524 ◽

pp. 155-169 ◽

Cited By ~ 8

Author(s):

JA Bosch ◽

JC Cornwell ◽

WM Kemp

Keyword(s):

Nitrogen Cycling ◽

Inorganic Nitrogen ◽

Short Term ◽

Oxygen Conditions ◽

Short Term Effects

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Changes of Soil Microbes Related with Carbon and Nitrogen Cycling after Long-Term CO2 Enrichment in a Typical Chinese Maize Field

Sustainability ◽

10.3390/su12031250 ◽

2020 ◽

Vol 12 (3) ◽

pp. 1250 ◽

Cited By ~ 1

Author(s):

Tiantian Diao ◽

Zhengping Peng ◽

Xiaoguang Niu ◽

Rongquan Yang ◽

Fen Ma ◽

...

Keyword(s):

16S Rrna ◽

Nitrogen Cycling ◽

Relative Abundance ◽

Soil Microbes ◽

Inorganic Nitrogen ◽

Ammonia Oxidizing Bacteria ◽

Rhizospheric Soil ◽

Carbon And Nitrogen ◽

Carbon And Nitrogen Cycling ◽

Maize Field

Elevated atmospheric CO2 concentration (eCO2) has been the most important driving factor and characteristic of climate change. To clarify the effects of eCO2 on the soil microbes and on the concurrent status of soil carbon and nitrogen, an experiment was conducted in a typical summer maize field based on a 10-year mini FACE (Free Air Carbon Dioxide Enrichment) system in North China. Both rhizospheric and bulk soils were collected for measurement. The soil microbial carbon (MBC), nitrogen (MBN), and soil mineral N were measured at two stages. Characteristics of microbes were assayed for both rhizospheric soil and bulk soils at the key stage. We examined the plasmid copy numbers, diversities, and community structures of bacteria (in terms of 16s rRNA), fungi (in terms of ITS-internal transcribed spacer), ammonia oxidizing bacteria (AOB) and denitrifiers including nirK, nirS, and nosZ using the Miseq sequencing technique. Results showed that under eCO2 conditions, both MBC and MBN in rhizospheric soil were increased significantly. The quantity of ITS was increased in the eCO2 treatment compared with that in the ambient CO2 (aCO2) treatment, while the quantity of 16s rRNA in rhizospheric soil showed decrease in the rhizospheric soil in the eCO2 treatment. ECO2 changed the relative abundance of microbes in terms of compositional proportion of some orders or genera particularly in the rhizospheric soil-n particular, Chaetomium increased for ITS, Subgroups 4 and 6 increased for 16s rRNA, Nitrosospira decreased for AOB, and some genera showed increase for nirS, nirK, and nosZ. Nitrate N was the main inorganic nitrogen form at the tasseling stage and both quantities of AOB and denitrifiers, as well as the nosZ/(nirS+nirK) showed an increase under eCO2 conditions particularly in the rhizospheric soil. The Nitrosospira decreased in abundance under eCO2 conditions in the rhizospheric soil and some genera of denitrifiers also showed differences in abundance. ECO2 did not change the diversities of microbes significantly. In general, results suggested that 10 years of eCO2 did affect the active component of C and N pools (such as MBC and MBN) and both the quantities and relative abundance of microbes which are involved in carbon and nitrogen cycling, possibly due to the differences in both the quantities and component of substrate for relevant microbes in the rhizospheric soils.

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Metagenomic analysis of nitrogen and methane cycling in the Arabian Sea oxygen minimum zone

PeerJ ◽

10.7717/peerj.1924 ◽

2016 ◽

Vol 4 ◽

pp. e1924 ◽

Cited By ~ 48

Author(s):

Claudia Lüke ◽

Daan R. Speth ◽

Martine A.R. Kox ◽

Laura Villanueva ◽

Mike S.M. Jetten

Keyword(s):

Nitrogen Cycle ◽

Arabian Sea ◽

Nitrogen Loss ◽

Global Ocean ◽

Ammonium Oxidation ◽

Active Nitrogen ◽

Core Zone ◽

Methane Cycling ◽

Oxygen Minimum ◽

Oxygen Concentrations

Oxygen minimum zones (OMZ) are areas in the global ocean where oxygen concentrations drop to below one percent. Low oxygen concentrations allow alternative respiration with nitrate and nitrite as electron acceptor to become prevalent in these areas, making them main contributors to oceanic nitrogen loss. The contribution of anammox and denitrification to nitrogen loss seems to vary in different OMZs. In the Arabian Sea, both processes were reported. Here, we performed a metagenomics study of the upper and core zone of the Arabian Sea OMZ, to provide a comprehensive overview of the genetic potential for nitrogen and methane cycling. We propose that aerobic ammonium oxidation is carried out by a diverse community ofThaumarchaeotain the upper zone of the OMZ, whereas a low diversity ofScalindua-like anammox bacteria contribute significantly to nitrogen loss in the core zone. Aerobic nitrite oxidation in the OMZ seems to be performed byNitrospina spp. and a novel lineage of nitrite oxidizing organisms that is present in roughly equal abundance asNitrospina. Dissimilatory nitrate reduction to ammonia (DNRA) can be carried out by yet unknown microorganisms harbouring a divergentnrfAgene. The metagenomes do not provide conclusive evidence for active methane cycling; however, a low abundance of novel alkane monooxygenase diversity was detected. Taken together, our approach confirmed the genomic potential for an active nitrogen cycle in the Arabian Sea and allowed detection of hitherto overlooked lineages of carbon and nitrogen cycle bacteria.

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Intercropping affects genetic potential for inorganic nitrogen cycling by root-associated microorganisms in Medicago sativa and Dactylis glomerata

Applied Soil Ecology ◽

10.1016/j.apsoil.2017.06.040 ◽

2017 ◽

Vol 119 ◽

pp. 260-266 ◽

Cited By ~ 15

Author(s):

Ming Zhao ◽

Christopher M. Jones ◽

Johan Meijer ◽

Per-Olof Lundquist ◽

Petra Fransson ◽

...

Keyword(s):

Medicago Sativa ◽

Nitrogen Cycling ◽

Inorganic Nitrogen ◽

Dactylis Glomerata ◽

Genetic Potential

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Development of Air Supply Control Technology in Sidestream MLE Process by Measuring Conductivity

Journal of Korean Society of Environmental Engineers ◽

10.4491/ksee.2020.42.3.97 ◽

2020 ◽

Vol 42 (3) ◽

pp. 97-109

Author(s):

Shinyo Chang ◽

Pung Shik Shin ◽

Yeon-Koo Jeong ◽

Young June Choi

Keyword(s):

Water Quality ◽

Removal Efficiency ◽

Biological Treatment ◽

Inorganic Nitrogen ◽

Ammonia Nitrogen ◽

Control Technology ◽

Treatment Efficiency ◽

Air Supply ◽

Total Inorganic Nitrogen ◽

Nitrogen Treatment

Objectives : This study aimed to achieve improved process performance and energy saving by developing a technology to control the air supply of an aerobic basin by measuring the conductivity in the anoxic basin.Methods : To verify whether conductivity can be used as an operation indicator of biological treatment, the correlation analysis between water quality factor and conductivity of each process was conducted by dividing into summer (methanol input), winter and autumn periods. An empirical formula was presented by briefly arranging the required air quantity formula, and a quick reference was prepared by putting air supply in the conductivity range sequentially. The performance evaluation was judged based on the removal efficiency of ammonia nitrogen and total inorganic nitrogen, SNR and SDNR, the change of air supply, the stability of the process against inflow change.Results and Discussion : The seasonal correlation coefficients of conductivity and water quality items were calculated in the order of ammonia nitrogen, total inorganic nitrogen, DOC, and phosphate in the range of 0.5267 ~ 0.9115. It was found that the conductivity could be used as an operation indicator of the biological treatment process with a correlation coefficient of 0.5 or more. The regression equations for the conductivity and ammonia nitrogen are secured by season, so it is possible to estimate the ammonia nitrogen through the conductivity. At the end of the aerobic basin DO was 3.4 mg/L, the nitrogen treatment efficiency in winter was the best. The aerobic basin DO can be controlled by the air supply, and it can be seen that it is possible to control the air supply and improve the nitrogen treatment efficiency by directly measuring the conductivity having a high correlation with nitrogen. An empirical formula for estimating the required air volume through conductivity and inflow is presented. A' and (B' + X') are 0.0589 (m3-air/h)/(m3/h)/(μS/cm) and –77.562 (m3-air/h)/(m3/h). The result of automatic control of air supply according to the measured conductivity of anoxic tank during winter season showed that total inorganic nitrogen removal efficiency and SDNR were 8.3% and 0.007 g-N/g-MLSS/d higher than the actual plant conditions, respectively. During the automatic control period, the air supply/inflow average ratio was 36 (m3-air/h)/(m3/h), which could reduce the air supply by 21.7% compared to the actual plant conditions.Conclusions : The air supply can be estimated from the flow rate and conductivity. The air supply control technology of the conductivity-based MLE process will be able to simultaneously improve nitrogen removal efficiency and reduce energy consumption.

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