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Background: Neuro-Behçet's disease (NBD), characterized by isolated intracranial hypertension, is a rarely encountered condition, especially in children. In this study, we describe the treatment of a pediatric patient with NBD, who exhibited isolated intracranial pressure elevation as indicated by the initial manifestation of diplopia and physical examination finding of papilledema. Case presentation: An 8-year-old boy was admitted to the hospital with a confirmed diagnosis of Behçet's disease (BD) over eight months. The patient also presented with the symptom of diplopia for three days. The evaluation of the patient's nervous system did not reveal any apparent abnormalities. The measurement of cerebrospinal fluid pressure yielded a reading of 470 mm H2O. The examination of the fundus indicated papilledema, and imaging scans revealed evidence of focal demyelination. The symptoms of the child showed alleviation after the administration of mannitol, methylprednisolone, and azathioprine. Furthermore, this study involved a comprehensive analysis of 18 cases of NBD with isolated intracranial hypertension, comprising one case reported herein and 17 cases from the literature review. Three cases were children, and an equal distribution of males and females 9:9 was noted. The average age at the onset of symptoms was 24.7 years (8-38 years). Headache (90%) was the most commonly reported clinical manifestation, followed by blurred vision or diplopia (80%). The ocular manifestations included papilledema (100%), abducent nerve paralysis (20%) and local eye hemorrhages in the retina (30%). Notably, 88.9% of these ocular manifestations were relieved or cured after treatment. Conclusion: This study presents the first reported case of NBD with isolated intracranial hypertension in the pediatric population of China. In a child with Bechet's disease presenting with features of raised intracranial pressure, it is important to be aware of neuro Bechet's presenting with intracranial hypertension without other neurological abnormalities. This will help make early diagnosis, institute treatment and prevent sequelae resulting from untreated raised intracranial pressure. [ABSTRACT FROM AUTHOR]

Background: Some juvenile idiopathic arthritis (JIA) patients have a familial aggregation of the disease, and a few have been found to have a juvenile arthritis (JA) phenotype caused by a genetic mutation. JA due to LACC1 defects is a rare condition and it was never reported in China. Methods: The clinical and molecular characteristics of a child with LACC1 gene mutation‐related juvenile arthritis, diagnosed by high‐throughput sequencing in Wuhan children's Hospital in 2021 were analyzed retrospectively; The literature and database were reviewed to summarize the clinical data and genotype characteristics of patients with JA caused by LACC1 gene mutation. Results: Here, we report a 19‐month‐old Chinese male patient who presented with bilateral limb edema without a history of fever. Laboratory tests showed had moderate anemia and signs of inflammation: hemoglobin of 76 g/L, white blood cell count of 20.53 × 109, and platelet count of 1194 × 109; MRI showed the patient had synovitis and tenosynovitis in bilateral hands and wrists. Whole‐exome sequencing (WES) detected compound heterozygous variants, novel c.446_449dupTAAA and c.889T>C, in the LACC1 gene. Of the 52 patients reported in the literature (including this case), 38.9% had clinical symptoms of systemic juvenile idiopathic arthritis (sJIA), which tended to be caused by loss‐of‐function (LOF) mutation. Findings in this study expanded the spectrum of pathogenic variants and reveal the phenotypic heterogeneity of LACC1‐JA. Conclusions: Our study reported a rare case of juvenile arthritis, which is due to the compound heterozygous mutation of LACC1, including a new novel frameshift mutation c.446_449dupTAAA, and LACC1 C297R variant causes disease by potentially modifying the local conformation of proteins. The clinical and genetic findings in our study show that LACC1‐JA is highly heterogeneous, and gene testing is required for juvenile arthritis patients with a high inflammatory response at a young onset age. [ABSTRACT FROM AUTHOR]

The largemouth bass Micropterus salmoides is a carnivorous fish species that is widely farmed in China using artificial compound feeds. Alterations from its natural diet affect intestinal microbiota structure and growth performance and can reduce disease and stress resistance. In this study, we examined growth performance, immunity, intestinal microflora, and resistance to Aeromonas veronii infections-fed prey fish (PF) and artificial compound feed (ACF). Weight gains in the PF group were 27% significantly (P < 0.05) greater than the ACF group. Antioxidant enzyme activities of superoxide dismutase, catalase, and glutathione peroxidase and mRNA expression of inducible nitric oxide synthase, transforming growth factor β1, and interleukin 10 were also significantly higher than for the ACF group. In contrast, levels of malondialdehyde were lower for the PF group consistent with the antioxidant activities. These results indicated that the commercial artificial compound diet reduced the immunity and anti-stress ability of the fish. Survival in against A. versonii infection were similar although the PF fish resisted the infection to a greater extent and succumbed at a slower rate. The gut microbiomes also differed between the PF and ACF feeding groups and operational taxonomic units were 1105.75 and 971.63, respectively. The high abundance of Verrucomicrobia were associated with weight gain and enhanced immunity for the PF group and were significantly (P < 0.05) higher than that in ACF group. Bacteroidetes abundance was closely related to weight loss in the ACF group. The results of this study suggest that the changes in intestinal microflora structure caused by dietary changes in largemouth bass affected its growth performance and reduce its immune and anti-stress abilities and provide a theoretical basis for the improvement of largemouth bass compound feeds. [ABSTRACT FROM AUTHOR]

Cinnamomum cassia (L.) Presl (cinnamon), an important folk medicine is widely used to prevent osteoporosis for long time in China. Our study aimed to investigate the anti-osteoporosis activity and mechanisms of cinnamon extracts obtained by supercritical CO2 extraction (SFE) and identify activity associated chemical components by gas chromatography-mass spectrometry. The cinnamon SFE exhibited superior anti-osteoporosis efficacy in an ovariectomised mice model to common alcohol extracts. It could induce calcified nodules and ALP activity, upregulate the mRNA expression of ALP, BMP-2, and RUNX2 in MC3T3-E1 cells. The major chemical classes of cinnamon extracts were alcohol esters (28.2%), and terpenes (16.1%). The spectrum-activity analysis indicated that the potential chemical-markers of extracts could be (E)-Cinnamaldehyde, γ-Sitosterol, and (Z, Z)-9,12-Octadecadienoic acid, which could induce the proliferation and ALP activity in MC3T3-E1 cells. Our study revealed the promising applications of the cinnamon SFE in prevention of osteoporosis, and identified its anti-osteoporosis associated compounds. [ABSTRACT FROM AUTHOR]

Largemouth bass is an important commercially farmed fish in China, but the rapid expansion of its breeding has resulted in increased incidence of diseases caused by bacteria, viruses and parasites. In this study, moribund largemouth bass containing ulcer foci on body surfaces indicated the most likely pathogens were iridovirus and rhabdovirus members and this was confirmed using a combination of immunohistochemistry, cell culture, electron microscopy and conserved gene sequence analysis. We identified that these fish had been co-infected with these viruses. We observed bullet-shaped virions (100–140 nm long and 50–100 nm in diameter) along with hexagonal virions with 140 nm diameters in cell culture inoculated with tissue homogenates. The viruses were plaque purified and a comparison of the highly conserved regions of the genome of these viruses indicated that they are most similar to largemouth bass virus (LMBV) and hybrid snakehead rhabdovirus (HSHRV), respectively. Regression infection experiments indicated fish mortalities for LMBV-FS2021 and HSHRV-MS2021 were 86.7 and 11.1%, respectively. While co-infection resulted in 93.3% mortality that was significantly (p < 0.05) higher than the single infections even though the viral loads differed by >100-fold. Overall, we simultaneously isolated and identified LMBV and a HSHRV-like virus from diseased largemouth bass, and our results can provide novel ideas for the prevention and treatment of combined virus infection especially in largemouth bass. [ABSTRACT FROM AUTHOR]

Crop production systems involving the use of high rates of fertilizer application caused significant losses of nitrogen (N) and phosphorus (P) to the environment, resulting in air pollution and water body eutrophication. Quantitating N and P losses and its drivers in crop production systems was critical for optimizing water and fertilizer management measures to mitigate the nutrient losses. However, N and P losses estimation remains highly uncertain in the field at event scale. We here quantify daily N and P losses and its drivers (daily N and P water input, N and P uptake, N and P water surplus, water loss, etc.) in rice-rapeseed growing systems by high-frequency field experiments at event scale in Central China. Results revealed that there were significant trade-off relationships between daily uptake and surplus for N and P during the whole growing stages both for rice and rapeseed. Although it was not significantly related in heading to mature stage for rapeseed, synergies between daily input or surplus and loss were found for N. Redundancy analysis revealed that water input and leaching loss contributed most for N and P loss in rice and rapeseed. The nutrient losses in easier stages should be reduced by postponing the base fertilizer and making it in line with the crop uptake. The study enhanced our knowledge of N and P losses mechanism for crop production systems and provided a scientific basis for optimization of water and fertilizer managements and N and P loss estimation models. [ABSTRACT FROM AUTHOR]

A record‐breaking rainfall event was initiated between the urban heat island (UHI) and a small trumpet‐shaped mountain (Huadu Mountain) to its north in Guangzhou City at midnight of May 6, 2017. Numerically simulating the convection initiation (CI) was challenging due to insufficient model resolution and inaccurate boundary layer parameterization, this study therefore examined the pre‐convective mesoscale processes based on their four‐dimensional analyses obtained through data assimilation of radar and surface observations using the four‐dimensional Variational Doppler Radar Analysis System (VDRAS). Results suggested that the Huadu Mountain to the north of Guangzhou City played a crucial role in the CI through orographic blocking and nighttime cooling. Dynamically, the mountain blocked the upstream airflow causing an accumulation of water vapor in boundary layers; thermally, the large near‐surface temperature gradients between the mountain and its southern foot area induced northerly downslope winds and low‐level convergences and updrafts. The downslope winds enhanced the accumulation of boundary‐layer water vapor, which was then transported to higher altitudes over the CI region by the updrafts, thus resulting in the formation and growth of cloud water above the altitude of 1 km. In addition to the mountain, the UHI also played an important role by increasing the magnitude of the low‐level convergence and influencing its horizontal distribution. These findings urge attentions to the critical roles of small‐scale orography and its interaction with urban underlying surface in initiating local rainstorm events. Key Points: Orographic blocking and northerly downslope wind resulted in the accumulation of water vapor in the boundary layerThe strong nighttime cooling of the mountain induced low‐level wind convergence and updraft for convection initiationThe urban heat island also played an important role in enhancing the low‐level wind convergence [ABSTRACT FROM AUTHOR]

Work environments can affect job satisfaction and psychological well-being. Using the job demand-control model as a foundation, this study aimed to explore the relationships between physical and psychosocial work environments and psychological well-being and job satisfaction in the workplace. A multistage sampling method was used with the 2012 China Labor-force Dynamics Survey among 4442 employees. Our outcome measures included psychological well-being and job satisfaction. The final model showed migrants (odds ratio [OR] = 1.34, 95% confidence interval [CI] = 1.13-1.60) and nonmanagerial employees (OR = 1.49, 95% CI = 1.25-1.78) who worked in general enterprises (OR= 1.61, 95% CI = 1.34-1.92) or suffered longer weekly work hours (OR = 1.42, 95% CI = 1.24-1.63) had worse psychological well-being or lower job satisfaction. Following the job demand-control model, higher job demands and lower job autonomy were significantly and positively associated with worse psychological well-being and lower job satisfaction. This study highlights that improved work environments can protect employees' well-being. Policymakers must provide better work environments. They must consider its physical environment (stable work contract and short work hours) and psychosocial environment (low job demands and high job autonomy) aspects, particularly for migrants and nonmanagerial employees. [ABSTRACT FROM AUTHOR]

Reliable detection and attribution of changes in nitrogen (N) runoff from croplands are essential for designing efficient, sustainable N management strategies for future. Despite the recognition that excess N runoff poses a risk of aquatic eutrophication, large-scale, spatially detailed N runoff trends and their drivers remain poorly understood in China. Based on data comprising 535 site-years from 100 sites across China's croplands, we developed a data-driven upscaling model and a new simplified attribution approach to detect and attribute N runoff trends during the period of 1990–2012. Our results show that N runoff has increased by 46% for rice paddy fields and 31% for upland areas since 1990. However, we acknowledge that the upscaling model is subject to large uncertainties (20% and 40% as coefficient of variation of N runoff, respectively). At national scale, increased fertilizer application was identified as the most likely driver of the N runoff trend, while decreased irrigation levels offset to some extent the impact of fertilization increases. In southern China, the increasing trend of upland N runoff can be attributed to the growth in N runoff rates. Our results suggested that increased SOM led to the N runoff rate growth for uplands, but led to a decline for rice paddy fields. In combination, these results imply that improving management approaches for both N fertilizer use and irrigation is urgently required for mitigating agricultural N runoff in China. [ABSTRACT FROM AUTHOR]

• The systemic 24Model is mainly based on the Domino Theory and Swiss Cheese Model. • The theoretical evolution of the 24Model and its applications are presented. • 24Model can be applied to intelligent accident analysis with its precise definitions. • The results of accident analysis were used to develop a safety training system. • A quantitative measurement system of safety culture was designed using 24Model. Systemic accident causation models are widely used in safety research. However, there exists a gap between research and practice. This paper introduces a popular systemic accident model (24Model) in China, describing its source and logical structure. Besides, the applications of 24Model in safety theoretical research and practice are examined based on statistics of publications and case study. The results show that the 24Model is mainly based on the domino theory and Swiss cheese model, and it is also influenced by the models of Bird and Stewart. It has been evolving into its sixth version. The systems thinking of 24Model was explained in the fifth and sixth versions. The main research topics of 24Model are accident analysis, safety management, and safety culture. As a formal method, 24Model has supported the development of an accident analysis and training system and a safety culture analysis process. In addition, 24Model can support safety science fundamental research, which facilitates the understanding of safety science and educational programs in this field. In the future, 24Model would provide a more accurate classification framework to support the intelligent accident analysis, company safety management, and education programs. [ABSTRACT FROM AUTHOR]

Excessive anthropogenic nitrogen (N) and phosphorus (P) inputs have caused an alarming increase in harmful cyanobacterial blooms, threatening sustainability of lakes and reservoirs worldwide. Hypertrophic Lake Taihu, China’s third largest freshwater lake, typifies this predicament, with toxic blooms of the non-N2 fixing cyanobacteria Microcystis spp. dominating from spring through fall. Previous studies indicate N and P reductions are needed to reduce bloom magnitude and duration. However, N reductions may encourage replacement of non-N2 fixing with N2 fixing cyanobacteria. This potentially counterproductive scenario was evaluated using replicate, large (1000 L), in-lake mesocosms during summer bloom periods. N+P additions led to maximum phytoplankton production. Phosphorus enrichment, which promoted N limitation, resulted in increases in N2 fixing taxa (Anabaena spp.), but it did not lead to significant replacement of non-N2 fixing with N2 fixing cyanobacteria, and N2 fixation rates remained ecologically insignificant. Furthermore, P enrichment failed to increase phytoplankton production relative to controls, indicating that N was the most limiting nutrient throughout this period. We propose that Microcystis spp. and other non-N2 fixing genera can maintain dominance in this shallow, highly turbid, nutrient-enriched lake by outcompeting N2 fixing taxa for existing sources of N and P stored and cycled in the lake. To bring Taihu and other hypertrophic systems below the bloom threshold, both N and P reductions will be needed until the legacy of high N and P loading and sediment nutrient storage in these systems is depleted. At that point, a more exclusive focus on P reductions may be feasible. [ABSTRACT FROM AUTHOR]

Rice field has been traditionally considered as a nonpoint source of reactive nitrogen (N) for the environment, while it, with surrounding ditches and ponds, also contributes to receiving N inputs from atmosphere and waterbodies and intercepting N outputs from rice field. However, a comprehensive assessment of the N source or sink of rice field for the environment is lacking. Here, we conducted the 3-year systematic observations and process-based simulations of N budget at the Jingzhou site in Central China. We identified the roles of rice field and evaluated the opportunities for shifting its role from N source (i.e., outputs > inputs) to sink (i.e., outputs ≤ inputs). Rice field was found to be a N source of 24.2–28.7 kg N ha−1 for waterbodies (including surface and ground waters), but a N sink (2.2–8.8 kg N ha−1) for the atmosphere for the wet and normal year climatic scenarios. The "4R-nutrient stewardship" (i.e., using the right type of N fertilizers, at right rate, right time, and in right place) applied in rice field was sufficient for the source-to-sink shift for the atmosphere for dry year climatic scenario, but needed to implement together with improvements of irrigation and drainage for waterbodies. Furthermore, with the combination of these improved management technologies, rice field played a role as a N sink of up to 22.8 kg N ha−1 for the atmosphere and up to 2.0 kg N ha−1 for waterbodies, along with 24% decrease in irrigation water use and 21% decrease in N application rate without affecting rice yield and soil fertility. Together these findings highlight a possibility to achieve an environmental-friendly rice field by improving agricultural management technologies. [Display omitted] • Method is introduced to evaluate the role of rice field as N source or sink. • Rice field is N source for waterbody, but a N sink for atmosphere under wet climate. • Source-to-sink shift can be achieved by improving both water and N management. Rice field acted as N source for waterbody and for atmosphere under dry climate, but could be shifted to a N sink by improving agricultural management technologies. [ABSTRACT FROM AUTHOR]

• Raindrop-induced ejection contribute largely to N and P runoff losses. • The ejection is mainly regulated by rainfall intensity and initial concentrations. • Physical-based solute transport model is updated for multiple-site assessment. Nitrogen (N) and phosphorous (P) ejections driven by raindrops promote the solute concentrations in the surface runoff and thereby the runoff losses from croplands. Compared to a considerable number of studies on upland fields, little evidence for the importance of raindrop-induced ejection has been generated for rice paddies primarily due to the lack of field observations and appropriate modeling system. Our extensive rainfall simulation experiments, along with the update of a physical-based solute transport model, shed new light onto the contribution made by raindrop-induced ejection to the total runoff losses from 6 typical rice paddies across China. Raindrop-induced ejection accounted for 22–59 % to 27–63 % of the total runoff losses of N and P across China, respectively, regardless of rice-growing stages. The rainfall intensity and initial concentrations in ponded water explained most (43 % for N and 53 % for P) of the variance of raindrop-induced ejection. N and P runoff losses were further underestimated by 23 % and 29 %, respectively, if ignoring the raindrop-induced ejection at soil-water interface in the model. Progress toward mitigating the runoff losses from rice paddies and associated water pollution will be difficult without reduction in the raindrop-induced ejection particularly in the rice paddies with higher extreme precipitation and more fertilizer application in future. [ABSTRACT FROM AUTHOR]

Nitrogen losses in rice paddy fields pose a high risk to surrounding aquatic environment. While the surface N losses have garnered considerable attention in recent years, subsurface flux, including vertical leaching and near-ditch lateral seepage, has barely been quantified. To understand how it impacts the N run off, we collected three-year high-frequency and systematic field observations and adopted a two-dimensional quantitative model coupling water, nitrogen dynamics and crop growth. We quantified the magnitude and dynamics of subsurface N loss during rice growing season. Our results showed that subsurface N loss, reaching 6.2 kg N ha−1 and 4% of total applied N in rice growing seasons, was 2-fold larger than surface N runoff, in which lateral seepage contributed 33%. The driving factors include hydraulic gradients brought by ponded water depth and ditch water level. Based on our study, optimized irrigation management and conservation tillage were priority in mitigating subsurface N loss, with 41% and 32% reduction potential, respectively, and improved ditch-pond system combined with irrigation-drainage management could also be an effective solution. Together, these findings highlight an important role of subsurface flux including lateral seepage, which could be instrumental for future water-quality improvements in rice paddy-ditch landscape. • Subsurface flux plays a significant role in dissolved nitrogen loss from rice paddies in central China. • Lateral seepage contributes substantially to subsurface N loss. • The driving factors include hydraulic gradients brought by ponded water depth and ditch water level. • Subsurface N loss could be largely mitigated by optimized irrigation management, conservation tillage and improved ditch-pond system. [ABSTRACT FROM AUTHOR]

Quantifying the surface runoff losses of nitrogen (N) and phosphorus (P) at the regional scale is still challenging, mainly due to the model deficiencies and the lack of high-resolution data of agricultural management practices. Here, we re-evaluate N and P runoff losses from single, early and late rice systems in China, using a newly-developed model that was constrained by 127 rainfall-runoff events in 11 sites and driven by the fertilization and irrigation schemes from national surveys covering most of rice-producing provinces. Results show that national N and P runoff losses from rice paddies were 272.6 ± 101.2 Gg N yr−1 and 17.0 ± 6.4 Gg P yr−1, which were 38% and 12% less than previous model estimates, respectively, but 43% more than those of the first National Pollution Census Program (NPCP). The hotspots of N and P runoff losses were identified, most of which occurred in south China (60% of the total), generated during non-fertilization period (>65%), and took place in single rice system (∼50%). These losses might be mitigated by ∼90% through the increase in weir outlet height and the application of shallow-wet irrigation, but remain relatively stable even if optimizing fertilization scheme. The detailed assessment of mitigation potentials highlights an urgency in environmental policy regulation as well as farmers' accessibility to advanced irrigation technologies, which is expected to inform promotion towards more effective non-point source pollution controls in China and other rice-producing countries. Image 1 • New rice paddy runoff module is developed for large-scale simulations. • N/P runoff losses from China's rice paddies are largely biased by previous studies. • Large spatio-temporal variability of N and P runoff losses is identified. • Runoff losses may be largely mitigated by improving water management. [ABSTRACT FROM AUTHOR]

Extreme climate events constitute a major risk to global food production. Among these, extreme rainfall is often dismissed from historical analyses and future projections, the impacts and mechanisms of which remain poorly understood. Here we used long-term nationwide observations and multi-level rainfall manipulative experiments to explore the magnitude and mechanisms of extreme rainfall impacts on rice yield in China. We find that rice yield reductions due to extreme rainfall were comparable to those induced by extreme heat over the last two decades, reaching 7.6 ± 0.9% (one standard error) according to nationwide observations and 8.1 ± 1.1% according to the crop model incorporating the mechanisms revealed from manipulative experiments. Extreme rainfall reduces rice yield mainly by limiting nitrogen availability for tillering that lowers per-area effective panicles and by exerting physical disturbance on pollination that declines per-panicle filled grains. Considering these mechanisms, we projected ~8% additional yield reduction due to extreme rainfall under warmer climate by the end of the century. These findings demonstrate that it is critical to account for extreme rainfall in food security assessments., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

The control of agricultural nitrogen through inflow rivers is crucial for lake aquatic environment conservation, while nitrate is the main form of non-point source pollution of agricultural nitrogen in watersheds. Therefore, understanding the nitrate sources and transformation in the intensive-agricultural region was particularly concerned. Nitrate sources and transformation varied largely during some crucial periods or events. However, low-resolution sampling campaigns increased some uncertainties due to without considering the effect of key driving factors for identifying nitrate transformations and sources. In our study, high-frequency sampling and analysis of nitrogen and oxygen isotope, hydrochemical and Bayesian model was conducted at the Dagang River to capture nitrate sources and transformations and identify its response to rainfall-runoff process at the event scale. In addition, the N cycle process was refined by comparing the variation and relationship of water quality factors and isotopes before, during, and after rainfall. We found that nitrate and major ions derived from similar agricultural activities caused by anthropogenic factors, such as domestic sewage from rural residents and livestock waste, through field survey and principal component analysis. The δ 15 N-NO 3 - and δ 18 O-NO 3 - in Dagang River ranged from +0.05‰ to +9.94‰ and + 1.49‰ to +11.64‰, respectively. The spatio-temporal variations of nitrate isotopes and hydrochemical compositions of river water suggested that nitrification was the dominant nitrate transformation process although the mixing effect occurred in some periods, especially during, and after the rainfall. The relationship between NO 3 - /Cl - and Cl - ratios suggested the occurrence of denitrification in downstream of the river basin after the rainfall. The results of Bayesian model showed that livestock manure and groundwater contributed to the most (66.4 ± 31.9%) nitrate, which indicated the necessity to establish its regulatory policy to avoid the overuse of livestock manure and groundwater in Dagang River. This study benefit for developing concrete and legible management and conservation strategies for decreasing the effect of anthropogenic nitrogen loading on lake eutrophication., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Current estimates of China's ammonia (NH 3 ) volatilization from paddy rice differ by more than twofold, mainly due to inappropriate application of chamber-based measurements and improper assumptions within process-based models. Here, we improved the Jayaweera-Mikkelsen (JM) model through multiplying the concentration of aqueous NH 3 in ponded water by an activity coefficient that was determined based on high-frequency flux observations at Jingzhou station in Central China. We found that the improved JM model could reproduce the dynamics of observed NH 3 flux (R 2  = 0.83, n = 228, P < 0.001), while the original JM model without the consideration of activity of aqueous NH 3 overstated NH 3 flux by 54% during the periods of fertilization and pesticide application. The validity of the improved JM model was supported by a mass-balance-based indirect estimate at Jingzhou station and the independent flux observations from the other five stations across China. The NH 3 volatilization losses that were further simulated by the improved JM model forced by actual wind speed were in general a half less than previous chamber-based estimates at six stations. Difference in wind speed between the inside and outside of the chamber and insufficient sampling frequency were identified as the primary and secondary causes for the overestimation in chamber-based estimations, respectively. Together, our findings suggest that an in-depth understanding of NH 3 transfer process and its robust representation in models are critical for developing regional emission inventories and practical mitigation strategies of NH 3 .

Excessive anthropogenic nitrogen (N) and phosphorus (P) inputs have caused an alarming increase in harmful cyanobacterial blooms, threatening sustainability of lakes and reservoirs worldwide. Hypertrophic Lake Taihu, China's third largest freshwater lake, typifies this predicament, with toxic blooms of the non-N2 fixing cyanobacteria Microcystis spp. dominating from spring through fall. Previous studies indicate N and P reductions are needed to reduce bloom magnitude and duration. However, N reductions may encourage replacement of non-N2 fixing with N2 fixing cyanobacteria. This potentially counterproductive scenario was evaluated using replicate, large (1000 L), in-lake mesocosms during summer bloom periods. N+P additions led to maximum phytoplankton production. Phosphorus enrichment, which promoted N limitation, resulted in increases in N2 fixing taxa (Anabaena spp.), but it did not lead to significant replacement of non-N2 fixing with N2 fixing cyanobacteria, and N2 fixation rates remained ecologically insignificant. Furthermore, P enrichment failed to increase phytoplankton production relative to controls, indicating that N was the most limiting nutrient throughout this period. We propose that Microcystis spp. and other non-N2 fixing genera can maintain dominance in this shallow, highly turbid, nutrient-enriched lake by outcompeting N2 fixing taxa for existing sources of N and P stored and cycled in the lake. To bring Taihu and other hypertrophic systems below the bloom threshold, both N and P reductions will be needed until the legacy of high N and P loading and sediment nutrient storage in these systems is depleted. At that point, a more exclusive focus on P reductions may be feasible.