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Responses of nutrient biogeochemistry and nitrogen cycle to seasonal upwelling in coastal waters of the eastern Hainan Island

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Acta Oceanologica Sinica 2022年第6期41卷 99-113页

作者： Nan Zhou Sumei Liu Guodong Song Yunyan Zhang Lingyan Wang Xiaoyan Ning Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Chemistry Theory and Technology of Ministry of EducationOcean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China

The coastal upwelling has profound influence on the surrounding ecosystem by supplying the nutrient-replete water to the euphotic zone.Nutrient biogeochemistry was investigated in coastal waters of the eastern Hainan Island in summer 2015 and autumn 2016.From perspectives of nutrient dynamics and physical transport,the nutrient fluxes entered the upper 50 m water depth(between the mixed layer and the euphotic zone)arisen from the upwelling were estimated to be 2.5-5.4 mmol/(m^(2)·d),0.15-0.28 mmol/(m^(2)·d),and 2.2-7.2 mmol/(m^(2)·d)for dissolved inorganic nitrogen(DIN),phosphate(DIP),and dissolved silicate(DSi),respectively,which were around 6-to 12-fold those in the background area.The upwelled nutrients supported an additional plankton growth of(14.70±8.95)mg/m^(2)for chlorophyll a(Chl a).The distributions of nitrateδ^(15)N andδ^(18)O above the 300 m water depth(top of the North Pacific Intermediate Water)were different among the upwelling area,background area in summer,and the stations in autumn,and the difference of environmental and biogeochemical conditions between seasons should be the reason.The higher DIN/DIP concentration ratio,nitrate concentration anomaly,and lower nitrate isotope anomaly(Δ(15,18))in the upper ocean in summer than in autumn indicated the stronger nitrogen fixation and atmospheric deposition,and the following fixed nitrogen regeneration in summer.The higher values of Chl a and nitrateδ^(15)N andδ^(18)O within the euphotic zone in autumn than the background area in summer suggested the stronger nitrate assimilation in autumn.The differences in relatively strength of the assimilation,nitrogen fixation and atmospheric deposition,and the following remineralization and nitrification between the two seasons made the higherδ^(18)O:δ^(15)N and larger difference of enzymatic isotope fractionation factors^(15)εand^(18)εfor nitrate assimilation in summer than in autumn above the North Pacific Tropical Water.

关键词： nutrients upwelling nitrateδ^(15)N andδ^(18)O nitrogen cycle South China Sea

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Periphytic biofilms-mediated microbial interactions and their impact on the nitrogen cycle in rice paddies

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Eco-Environment & Health 2022年第3期1卷 172-180页

作者： Zhihao Chen Jan Dolfing Shunyao Zhuang Yonghong Wu State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Zigui Three Gorges Reservoir Ecosystem Observation and Research Station of Ministry of Water Resources of the People's Republic of ChinaYichang 443605China University of Chinese Academy of Sciences Beijing 100049China Faculty of Energy and Environment Northumbria UniversityNewcastle Upon Tyne NE18QHUK

Rice paddies are unique waterlogged wetlands artificially constructed for agricultural production.Periphytic biofilms(PBs)at the soil–water interface play an important role in rice paddies characterized by high nutrient input but low utilization efficiency.PBs are composed of microbial aggregates,including a wide variety of microorganisms(algae,bacteria,fungi,protozoa,and metazoa),extracellular polymeric substances and minerals(iron,aluminum,and calcium),which form an integrated food web and energy flux within a relatively stable micro-ecosystem.PBs are crucial to regulate and streamline the nitrogen cycle by neutralizing nitrogen losses and improving rice production since PBs can serve as both a sink by capturing surplus nitrogen and a source by slowly re-releasing this nitrogen for reutilization.Here the ecological advantages of PBs in regulating the nitrogen cycle in rice paddies are illustrated.We summarize the key functional importance of PBs,including the intricate and delicate community structure,microbial interactions among individual phylotypes,a wide diversity of selfproduced organics,the active adaptation of PBs to constantly changing environments,and the intricate mechanisms by which PBs regulate the nitrogen cycle.We also identify the future challenges of microbial interspecific cooperation in PBs and their quantitative contributions to agricultural sustainability,optimizing nitrogen utilization and crop yields in rice paddies.

关键词： Periphytic biofilms Microbial aggregates Regulation nitrogen cycle

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Multiple isotopes reveal the driving mechanism of high NO_(3)^(-) level and key processes of nitrogen cycling in the lower reaches of Yellow River

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Journal of Environmental Sciences 2024年第4期138卷 597-606页

作者： Qianqian Zhang Huiwei Wang Lu Liu Tianlun Zhai Xueqing Zhang Hebei and China Geological Survey Key Laboratory of Groundwater Remediation Institute of Hydrogeology and Environmental GeologyChinese Academy of Geological SciencesHebei 050061China Geo-Environmental Monitoring Institute of Hebei Province Hebei 050011China Hebei Provincial Laboratory of Water Environmental Science Hebei 050037China Hebei Provincial Academy of Ecological Environmental Science Hebei 050037China

The continuous increase of nitrate(NO_(3)^(-))level in rivers is a hot issue in the world.However,the driving mechanism of high NO_(3)^(-)level in large rivers is still lacking,which has limited the use of river water and increased the cost of water treatment.In this study,multiple isotopes and source resolution models are applied to identify the driving mechanism of high NO_(3)^(-)level and key processes of nitrogen cycling in the lower reaches of the Yellow River(LRYR).The major sources of NO_(3)^(-)were sewage and manure(SAM)in the low-flow season and soil nitrogen(SN)and chemical fertilizer(CF)in the high-flow season.Nitrification was the most key process of nitrogen cycling in the LRYR.However,in the biological removal processes,denitrification may not occur significantly.The temporal variation of contributions of NO_(3)^(-)sources were estimated by a source resolution model in the LRYR.The proportional contributions of SAM and CF to NO_(3)^(-)in the low-flow and high-flow season were 32.5%-52.3%,44.2%-46.2%and 36.0%-40.8%,54.9%-56.9%,respectively.The driving mechanisms of high NO_(3)^(-)level were unreasonable sewage discharge,intensity rainfall runoff,nitrification and lack of nitrate removal capacity.To control the NO_(3)^(-)concentration,targeted measures should be implemented to improve the capacity of sewage and wastewater treatment,increase the utilization efficiency of nitrogen fertilizer and construct ecological engineering.This study deepens the understanding of the driving mechanism of high nitrate level and provides a vital reference for nitrogen pollution control in rivers to other area of the world.

关键词： Nitrate Driving mechanism nitrogen cycle Source apportionment Transformation Yellow River

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Effects of environmentally relevant concentrations of micro(nano)plastics on aquatic microorganisms:Changes in potential function but not in overall composition

Water Biology and Security

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Water Biology and Security 2024年第1期3卷 37-45页

作者： Zhenlu Wang Xianghong Dong Muzi Zhang Lei Gan Jian Shao Weiling Sun Key Laboratory of Animal Genetics Breeding and Reproduction in the Plateau Mountainous RegionMinistry of EducationGuizhou UniversityGuiyang550025China College of Animal Science Guizhou UniversityGuiyang550025China College of Environmental Sciences and Engineering The Key Laboratory of Water and Sediment SciencesMinistry of EducationPeking UniversityBeijing100871China

Micro(nano)plastics(MNPs)are a growing problem as persistent environmental pollutants.Here,we investigated the impact of MNPs on microorganisms in aquatic microbial floc exposed to NPs(80 nm)and MPs(8μm)for 35 days.Water quality indicators were tested weekly and microbiological analyses were conducted on Day 7 and 28 after exposure.The results showed that there were significant differences in the levels of total ammonia nitrogen or nitrite between the MNPs groups and the control group,spanning from Day 7 to Day 28.For the microbial response,microbial community richness in the NPs and MPs groups were significantly increased at Day 7.Functional prediction showed that the relative abundances of bacteria associated with the“Forms Biofilms”,“Potentially Pathogenic”,“Plastic Degradation”and nitrogen cycle processes were significantly different after MNPs exposure.The results suggest that MNPs had no significant effect on the microbial diversity of mature microbial flocs.Findings suggest MPs could cause an increase in the relative abundance of potentially pathogenic bacteria,while NPs do not.In addition,stress associated with MNPs affected the nitrogen cycle of microorganisms,and NPs exerted greater impacts than MPs.Findings from this study further our understanding of the impact of MNPs at environmentally relevant concentrations on microorganisms in aquatic ecosystems.

关键词： Nano-plastics Micro-plastics Aquatic microorganism Pathogenic bacteria nitrogen cycle

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Recent progress and challenges in structural construction strategy of metal-based catalysts for nitrate electroreduction to ammonia

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Journal of Energy Chemistry 2023年第11期86卷 69-83,I0003页

作者： Shuai Niu College of Ecology Taiyuan University of TechnologyTaiyuan 030024ShanxiChina

Ammonia plays an essential role in human production and life as a raw material for chemical fertilizers.The nitrate electroreduction to ammonia reaction(NO_(3)RR)has garnered attention due to its advantages over the Haber-Bosch process and electrochemical nitrogen reduction reaction.Therefore,it represents a promising approach to safeguard the ecological environment by enabling the cycling of nitrogen species.This review begins by discussing the theoretical insights of the NO_(3)RR.It then summarizes recent advances in catalyst design and construction strategies,including alloying,structure engineering,surface engineering,and heterostructure engineering.Finally,the challenges and prospects in this field are presented.This review aims to guide for enhancing the efficiency of electrocatalysts in the NO_(3)RR,and offers insights for converting NO_(3)-to NH_(3).

关键词： Nitrate electroreduction to ammonia reaction(NO^(3)RR) Structural construction strategy nitrogen cycle Metal-based catalysts Catalytic mechanism

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Quantifying soil nitrous oxide emissions in spring freezing-thawing period over different vegetation types in Northeast China

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Journal of Mountain Science 2022年第7期19卷 1919-1930页

作者： WU Bin MU Chang-cheng LIU Hui XU Ya-kun ZHANG Yue YANG Jia-shuo XU Wen-nian Hubei Key Laboratory of Construction and Management in Hydropower Engineering China Three Gorges UniversityYichang443002China College of Hydraulic&Environmental Engineering China Three Gorges UniversityYichang443002China Ministry of Education Key Laboratory of Sustainable Forest Ecosystem Management Northeast Forestry UniversityHarbin150040China Survey Planning and Design Institute of DaxinganlingNational Forestry and Grassland AdministrationDaxinganling165100China Engineering Research Center of Eco-Environment in Three Gorges Reservoir Region Ministry of EducationChina Three Gorges UniversityYichang443002China State Key Laboratory of Forest and Soil Ecology Institute of Applied EcologyChinese Academy of SciencesShenyang110016China Hubei Key Laboratory of Disaster Prevention and Mitigation China Three Gorges UniversityYichang443002China Key Laboratory of Geological Hazards on Three Gorges Reservoir Area Ministry of EducationYichang443002China

Environmental changes significantly alter the structure,diversity and activity of soil microbial communities during spring freezing-thawing period,leading to changes in the soil microbial nitrogen cycle.Changes in N_(2)O fluxes after land use conversion from primary forest to secondary forest,Korean pine plantation and cropland in northeast China have not been quantified.Field experiments were conducted to measure soil N_(2)O fluxes in a primary forest,two secondary forests,a Korean pine plantation,and one maize field in a temperate region in northeast China from 2017-03-06 to 2017-05-28.During the experimental period,the soil was exclusively a nitrogen source for all land uses.We found that N_(2)O emissions ranged from 15.63 to 68.74μg m^(-2) h^(-1),and cumulative N_(2)O emissions ranged from 0.33 to 2.10 kg ha^(-1) during the period.Cumulative N_(2)O emissions from the maize field were significantly higher than that from primary forest,Korean pine plantation,hardwood forest,and Betula platyphylla forest by 262.1% to 536.4%.Compared with other ecosystems in similar studies,the N_(2)O emission rates of all ecosystem types in this study were low during the spring thaw period.Stepwise multiple linear regression indicated that there were significant correlations between N_(2)O emissions and environmental factors(air temperature and soil temperature,soil water content,soil p H,NH_(4)^(+)-N,NO_(3)^(-)-N,and soil organic carbon).The results showed that conversion of land use from primary forest to hardwood forest,Korean pine plantation or maize field greatly increased soil N_(2)O emissions during spring freezing-thawing period,and N_(2)O emissions from primary forest were almost the same as those from Betula platyphylla forest.

关键词： N_(2)O emission Land use change Environmental factors nitrogen cycle

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Recent advances in nanostructured heterogeneous catalysts for N-cycle electrocatalysis

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Nano Research Energy 2022年第2期1卷 3-50页

作者： Jie Liang Qian Liu Abdulmohsen Ali Alshehri Xuping Sun Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China Institute for Advanced Study Chengdu UniversityChengdu 610106China Chemistry Department Faculty of ScienceKing Abdulaziz UniversityP.O.Box 80203Jeddah 21589Saudi Arabia College of Chemistry Chemical Engineering and Materials ScienceShandong Normal UniversityJinan 250014China

To restore the natural nitrogen cycle(N-cycle),artificial N-cycle electrocatalysis with flexibility,sustainability,and compatibility can convert intermittent renewable energy(e.g.,wind)to harmful or value-added chemicals with minimal carbon emissions.The background of such N-cycles,such as nitrogen fixation,ammonia oxidation,and nitrate reduction,is briefly introduced here.The discussion of emerging nanostructures in various conversion reactions is focused on the architecture/compositional design,electrochemical performances,reaction mechanisms,and instructive tests.Energy device advancements for achieving more functions as well as in situ/operando characterizations toward understanding key steps are also highlighted.Furthermore,some recently proposed reactions as well as less discussed C-N coupling reactions are also summarized.We classify inorganic nitrogen sources that convert to each other under an applied voltage into three types,namely,abundant nitrogen,toxic nitrate(nitrite),and nitrogen oxides,and useful compounds such as ammonia,hydrazine,and hydroxylamine,with the goal of providing more critical insights into strategies to facilitate the development of our circular nitrogen economy.

关键词： nitrogen cycle heterogeneous electrocatalyst ammonia synthesis metal−N2 battery

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Microbial activity related to N cycling in the rhizosphere of maize stressed by heavy metals

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Journal of Environmental Sciences 2005年第3期17卷 448-451页

作者： YANGYe CHENYing-xu TIANGuang-ming ZHANGZi-jian DepartmentofEnvironmentalEngineering ZhejiangUniversityHangzhou310029China DepartmentofEnvironmentalEngineering ZhejiangUniversityHangzhou310029China

A greenhouse experiment was carried out to compare differences in potential activities of ammonification, nitrification and denitrification in rhizosphere and bulk soil in a heavy-metal-stressed system. Exchangeable fractions of Cd, Cu and Cr were all higher in the rhizosphere of maize than in bulk soil. Results showed that the mineralization of N in soil was stimulated by low concentration of Cd. Addition of Cd at low levels stimulated the ammonifying and nitrifying activity in soil, while inhibitory influences were shown at high levels. Nitrifying bacteria was proved to be the most sensitive one, whilst the effect on denitrifying bacteria was very limited. Comparing Cd, Cu and Cr(VI) at 20 mg/kg soil, Cd was the most effective inhibitor of ammonification and denitrification, while Cr(VI) had the strongest inhibitory influence on nitrifying activity. Root exudates played important roles on the different exchangeable metal fractions and bacterial activities between rhizosphere and non-rhizosphere. Nitrate was the main form of mineral N in soil, as well as the main form of N absorbed by plants, but the formation and relative absorption of ammonium were promoted in response to high Cd exposure.

关键词： heavy metal nitrogen cycle rhizosphere root exudates

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Research progress and prospects of complete ammonia oxidizing bacteria in wastewater treatment

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Frontiers of Environmental Science & Engineering 2022年第9期16卷 151-160页

作者： Shaoping Luo Yi Peng Ying Liu Yongzhen Peng National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology Engineering Research Center of BeijingBeijing University of TechnologyBeijing 100124China Xinkai Water Environmental Investment Co.Ltd. Beijing 101101China Zhongshan Public Utilities Water Co.Ltd. Zhongshan 528400China

Complete ammonia oxidizing bacteria,or comammox bacteria(CAOB),can oxidize ammonium to nitrate on its own.Its discovery revolutionized our understanding of biological nitrification,and its distribution in both natural and artificial systems has enabled a reevaluation of the relative contribution of microorganisms to the nitrogen cycle.Its wide distribution,adaptation to oligotrophic medium,and diverse metabolic pathways,means extensive research on CAOB and its application in water treatment can be promoted.Furthermore,the energy-saving characteristics of high oxygen affinity and low sludge production may also become frontier directions for wastewater treatment.This paper provides an overview of the discovery and environmental distribution of CAOB,as well as the physiological characteristics of the microorganisms,such as nutrient medium,environmental factors,enzymes,and metabolism,focusing on future research and the application of CAOB in wastewater treatment.Further research should be carried out on the physiological characteristics of CAOB,to analyze its ecological niche and impact factors,and explore its application potential in wastewater treatment nitrogen cycle improvement.

关键词： Complete ammonia oxidizing(comammox) bacteria nitrogen cycle Physiological characteristics Wastewater treatment

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Description and Application of a Model for Simulating Regional nitrogen Cycling and Calculating nitrogen Flux

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Advances in Atmospheric Sciences 2008年第2期25卷 181-201页

作者：郑循华刘春岩韩圣慧 State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry (LAPC) Institute of Atmospheric Physics Chinese Academy of Sciences

A regional nitrogen cycle model, named IAP-N, was designed for simulating regional nitrogen （N） cycling and calculating N fluxes flowing among cultivated soils, crops, and livestock, as well as human, atmospheric and other systems. The conceptual structure and calculation methods and procedures of this model are described in detail. All equations of the model are presented. In addition, definitions of all the involved variables and parameters are given. An application of the model in China at the national scale is presented. In this example, annual surpluses of consumed synthetic N fertilizer; emissions of nitrous oxide （N2O）, ammonia （NH3） and nitrogen oxide （NOx）; N loss from agricultural lands due to leaching and runoff; and sources and sinks of anthropogenic reactive N （Nr） were estimated for the period 1961-2004. The model estimates show that surpluses of N fertilizer started to occur in the mid 1990s and amounted to 5.7 Tg N yr^-1 in the early 2000s. N20 emissions related to agriculture were estimated as 0.69 Tg N yr^-1 in 2004, of which 58% was released directly from N added to agricultural soils. Total NH3 and NOx emissions in 2004 amounted to 4.7 and 4.9 Tg N yr^-1, respectively. About 3.9 Tg N yr^-1 of N was estimated to have flowed out of the cultivated soil layer in 2004, which accounted for 33% of applied synthetic N fertilizer. Anthropogenic Nr sources changed from 2.8 （1961） to 28.1 Tg N yr^-1 （2004）, while removal （sinks） changed from to 2.1 to 8.4 Tg N yr^-1. The ratio of anthropogenic Nr sources to sinks was only 1.4 in 1961 but 3.3 in 2004. Further development of the IAP-N model is suggested to focus upon： Ca） inter-comparison with other regional N models; （b） overcoming the limitations of the current model version, such as adaptation to other regions, high-resolution database, and so on; and （c） developing the capacity to estimate the safe threshold of anthropogenic Nr source to sink ratios.

关键词： nitrogen cycle nitrous oxide reactive nitrogen model agriculture China

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