Eutrophication constrains driving forces of dissolved organic carbon biodegradation in metropolitan lake systems.

Dissolved organic carbon (DOC) components can be highly variable in aquatic ecosystems, and play a pivotal role in the global carbon cycles. To comprehend potential effects of nutrient enrichment on portion of DOC biodegradability (%BDOC), we conducted an extensive investigation on 26 urban lakes in a major metropolitan area in subtropical China in a small gradient of trophic levels from mesotrophic to light and middle eutrophic. In addition to field measurements on lake ambient conditions and laboratory analysis of DOC characteristics, we conducted a 28-day temperature-controlled incubation experiment, in which %BDOC of lake waters was determined. In the mesotrophic waters, %BDOC ranged from 0.6 to 41.4 % (11.2 ± 8.9 %). The %BDOC levels spanned from 5.2 to 20.2 % (10.7 ± 4.0 %) in the light eutrophic waters, and the %BDOC ranged from 2.7 to 35.0 % (13.7 ± 8.4 %) in the middle eutrophic waters. We found a significant change in DOC chemical composition across the study lakes characterized by shifting of trophic levels. Although the experiment found significant changes in the factors that can influence %BDOC, a significant difference was not observed in %BDOC among the three trophic levels. The %BDOC was primarily influenced by the inherent DOC concentration and aromaticity, with eutrophication leading to the varied driving factors of %BDOC in lake systems. We show that most of the lake water DOC was stable. The findings indicate the intricate interplay between biological metabolism and nutrient availability governing %BDOC dynamics in urban lake ecosystems.

Associations of minerals intake with colorectal cancer risk in the prostate, lung, colorectal, ovarian cancer screening trial.

Objective: Exploring the association between common mineral intake and the risk of colorectal cancer (CRC). Methods: We utilized the multivariate Cox proportional hazards model to assess the association between intake of minerals and the risk of CRC, estimating hazard ratios (HRs) and 95% confidence intervals (CIs). Results: A total of 101,686 eligible participants were included in the analysis of this study, including 1,100 CRC cases. After adjusting for potential confounders, we found that total zinc intake (HRQ4vs.Q1: 0.79, 95%CI 0.67-0.93; P for trend <0.05), iron intake (HRQ4vs.Q1: 0.81, 95%CI 0.68-0.96; P for trend <0.05), copper intake (HRQ4vs.Q1: 0.80, 95%CI 0.68-0.95; P for trend <0.05), selenium intake (HRQ4vs.Q1: 0.83, 95%CI 0.69-0.98; P for trend <0.05) were significantly negatively associated with the incidence of CRC, but magnesium intake in the appropriate range is associated with a reduced risk of CRC (HRQ3vs.Q1: 0.77, 95%CI 0.65-0.91; P for trend >0.05). Conclusion: Our findings suggested that an appropriate intake of total zinc, iron, copper, selenium and magnesium were associated with lower CRC risk.

Eutrophication-induced shifts cause diverse responses in the phoD community of a plateau freshwater lake.

Eutrophication is a critical environmental challenge affecting lakes globally. Mitigating trophic level under endogenous phosphorus release is an unsolved problem in eutrophic lakes. However, understanding the dynamics and assembly of microbial communities encoding the alkaline phosphatase (phoD community) and their responses during trophic transitions in eutrophic lakes is limited. In this study, we compared the composition and assembly mechanisms of phoD communities in four seasons in the Yilong Lake, a shallow lake of the Yunnan-Guizhou Plateau. The lake exhibits slightly eutrophic conditions in summer and mesotrophic conditions in spring, autumn, and winter. By analyzing seasonal variations, we observed that during summer, the relative abundance of Pseudomonas in the water had the highest value, while the Shannon-Wiener index of phoD communities was lowest. Mantel tests showed an increased Bray-Curtis dissimilarity of phoD communities in the water with rising eutrophication, a trend not observed in sediment. Notably, eutrophication heightened the homogeneity selection governing the assembly of phoD communities in water. The co-occurrence networks showed that the OTUs in the summer exhibited closer interconnections than those in other seasons. Additionally, the topological parameters from networks indicated that eutrophication is poised to instigate changes and modulate the dynamics of the microbial phoD community, resulting in markedly distinct seasonal behaviors. pH was identified as a critical factor directly influencing phoD community diversity via partial least squares path modeling (PLS-PM). This study shed light on our understanding of the seasonal dynamics of phoD communities and their pivotal role in phosphorus cycling in eutrophic lakes.

Dissolved organic matter (DOM) rather than warming and eutrophication directly affects partial pressure of CO2 (pCO2) in mesocosm systems.

Environmental warming and eutrophication pose significant challenges to shallow lake systems, where dissolved organic matter (DOM) serves as a diverse and intricate mixture of organic macromolecules, playing a pivotal role in aquatic ecosystems. Despite its complexity, comprehending the interplay between environmental changes and DOM composition alterations and their subsequent impacts on aqueous CO2 partial pressure (pCO2) is essential for a better understanding of carbon cycling. Yet, our current understanding in this realm remains limited. To address this gap, mesocosm systems were established to investigate how elevated water temperature and eutrophication, alongside changes in DOM composition, influence pCO2 dynamics. Results indicate that while temperature and nutrient levels do not directly influence pCO2 fluctuations, they indirectly affect aqueous pCO2 through their modulation of DOM composition. Elevated temperature and nutrient concentrations notably enhance both the production and degradation of indigenous protein-like organic matter and increase the accumulation of humic-like organic compounds, with phosphorus released from sediment playing a particularly significant role. Furthermore, the degradation rate of protein-like organic matter significantly exceeds its accumulation rate. On the other hand, the impact of water eutrophication on DOM composition surpasses that of temporal temperature variations, with a 2∼4 °C temperature rise showing minimal effects on DOM composition. Notably, the degradation of protein-like organic matter markedly increases aqueous pCO2, while the rise in humic-like organic matter in water exerts minimal influence on pCO2 concentrations. A comprehensive understanding of carbon cycling processes under environmental changes will facilitate effective management of lake ecosystems and the advancement of carbon mitigation technologies.

Explaining differences in self-focused and other-involved public health preventive behaviors between the US and China: the role of self- construal and health locus of control.

Background: This study examined national similarities and differences in people's engagement in health preventive behaviors during a public health crisis, as well as investigated the underlying individual-level psychological mechanisms. A conceptual distinction was made between self-focused and other-involved preventive behaviors in response to public health crises. Method: Two cross-sectional surveys were conducted in the United States (N = 888) and China (N = 844) during the early stage of the COVID-19 pandemic. Hayes' PROCESS was utilized to assess national differences in seven preventive behaviors, along with the mediating effects of self-construal and health locus of control. Results: The results showed that American participants reported greater engagement in self-focused preventive behaviors than Chinese, whereas Chinese participants reported greater engagement in other-involved preventive behaviors than Americans. Chinese participants also engaged more in other-involved than self-focused preventive behaviors. Self-construal and health locus of control partially explained the observed differences in engagement in preventive behaviors. Discussion: This study introduces a culture-sensitive approach to provide insights for crafting communication interventions that can enhance the effectiveness of health campaigns in the context of a public health crisis.

Rainstorm and strong wind weathers largely increase greenhouse gases flux in shallow ponds.

Shallow-water ponds represent the hotspots of greenhouse gas (GHG) emissions. Most current studies focus on the temporal dynamics for GHGs in water, with little consideration given to the effects of weather changes. In this study, we measured and compared the concentrations and fluxes of CO2, CH4, and N2O from a pond in Northeast China under different meteorological conditions. Results showed that the rates of CO2, CH4, and N2O emissions from pond into the atmosphere during strong winds were 85.85 ± 7.55 mmol m-2 d-1, 22.05 ± 6.80 mmol m-2 d-1, and 10.87 ± 0.72 µmol m-2 d-1, respectively, significantly higher than those measured during non-rain weather. Among which, over 88 % of CH4 emissions were contributed by ebullition. Meanwhile, the CO2 and N2O flux were also significantly higher during heavy rainfall, reaching 100.05 ± 19.76 mmol m-2 d-1 and 5.90 ± 1.03 µmol m-2 d-1, respectively. Strong winds and precipitation induced sediment disturbances, high gas transport coefficients, reduced photosynthesis and oxygen greatly promoted the GHGs escape evasion. Wind speed, air pressure, solar radiation, and dissolved oxygen in water were important influencing factors. Our results emphasize the importance of capturing short-term weather disturbance events, especially rainstorm and strong winds, to accurately assess the annual GHG budget from these shallow water ecosystems.

Escherichia coli and HPV16 coinfection may contribute to the development of cervical cancer.

Persistent human papillomavirus HPV infection is a necessary but insufficient condition for cervical cancer. Microorganisms are crucial environmental factors in cancers susceptibility and progression, recently attracting considerable attention. This study aimed to determine the infection status and relationship between high-risk HPV (HR-HPV) and lower genital tract infectious pathogens in cervical cancer and its precursors. From a retrospective and a prospective cohort analysis, Escherichia coli (E. coli) dominated the pathogens isolated from cervical discharges, and an isolation rate uptrend has been shown recently. HPV16 and E. coli's coinfection rate gradually increased with the severity of cervical intraepithelial neoplasia. The adhesion and invasion abilities of the isolated E. coli to HPV16-positive SiHa cells were evaluated in vitro. The TCGA database and cervical tissues samples analysis showed that IL-10 was upregulated in cervical cancer. IL-10 expression levels increased in tissue samples with the severity of cervical cancer and its precursors with HPV16 and E. coli coinfection. Although no significant changes in IL-10 production were observed in the co-culture supernatant, we hypothesized that Treg immune cells in the tumour microenvironment might be responsible for the local IL-10 upregulation, according to our data showing Foxp3 upregulation and an upward trend with the cervical intraepithelial neoplasia grading to cancer and tumours with E. coli and HPV16 coinfection. Our data provide insights into the possible role of E. coli in cervical cancer progression and suggest that the application of HPV and E. coli screening programs may be an effective strategy to relieve the burden of cervical cancer and its precursor lesions.

Denitrification regulates spatiotemporal pattern of N2O emission in an interconnected urban river-lake network.

Urban rivers are hotspots of N2O production and emission. Interconnected river-lake networks are constructed to improve the water quality and hydrodynamic conditions of urban rivers in many cities of China. However, the impact of the river-lake connectivity project on N2O production and emission remains unclear. This study investigated dissolved N2O and emission of the river-lake network in Wuhan City, China from March 2021 to December 2021. The results showed that river-lake connection greatly decreased riverine Nitrogen (N) concentration and increased dissolved oxygen (DO) concentration compare to traditional urban rivers. N2O emissions from the urban river interconnected with lakes (LUR: 67.3 ± 92.6 µmol/m2/d) were much lower than those from the traditional urban rivers (UR: 467.3 ± 1075.7 µmol/m2/d) and agricultural rivers (AR: 20.4 ± 15.3µmol/m2/d). Regression tree analysis suggested that the N2O concentrations were extremely high when hypoxia exists (DO < 1.6 mg/L), and TDN was the primary factor regulating N2O concentrations when hypoxia does not occur. Thus, we ascribe the low N2O emission in the LUR and AR to the lower N contents and higher DO concentrations. The microbial process of N2O production and consumption were quantitatively estimated by isotopic models. The mean proportion of denitrification derived N2O (fbD) was 63.5 %, 55.6 %, 42.3 % and 42.7 % in the UR, LUR, lakes and AR, suggested denitrification dominated N2O production in the urban rivers, but nitrification dominated N2O production in the lakes and AR. The positive correlation between logN2O and fbD suggested that denitrification is the key process to regulate the N2O production and emission. The abundance of denitrification genes (nirS and nirK) was much higher than that of nitrification genes (amoA and amoB), also evidenced that denitrification was the main N2O source. Therefore, river-lake interconnected projects changed the nutrients level and hypoxic condition, leading to the inhibition of denitrification and nitrification, and ultimately resulting in a decrease of N2O production and emission. These results advance the knowledge on the microbial processes that regulate N2O emissions in inland waters and illustrate the integrated management of water quality and N2O emission.

Response of dissolved carbon dioxide and methane concentration to warming in shallow lakes.

Shallow lake ecosystems are highly sensitive to temperature fluctuation because of their high water surface-to-volume ratios. Shallow lakes have been increasingly identified as a hotspot of CO2 and CH4 emissions, but their response to temperature variation remains unclear. Here, we report from a 5-month outdoor mesocosm experiment where we investigated the impacts of a projected 3.5 °C future warming and monthly temperature changes on lake CO2 and CH4, as well as the key drivers affecting the lake carbon cycling. Our results show that CO2 and CH4 concentrations had a significantly positive correlation with monthly temperatures. CH4 concentration was primarily regulated by monthly temperature, while nutrients effects on CO2 concentration overrode climate warming and temporal temperature changes. These findings imply the varied roles that temperature and nutrient levels can play on CO2 and CH4 dynamics in shallow lake systems. The relationship between temperature and CO2 concentration was nonlinear, showing a threshold of approximately 9 °C, at which CO2 concentration could be strongly modified by nutrient level in the lake systems. Understanding this complex relationship between temperature with CO2 and CH4 concentrations in shallow lakes is crucial for effective lake management and efficient control of greenhouse gases (GHGs) emissions.

Diel variability of carbon dioxide concentrations and emissions in a largest urban lake, Central China: Insights from continuous measurements.

Accurately quantifying the carbon dioxide (CO2) emissions from lakes, especially in urban areas, remains challenging due to constrained temporal resolution in field monitoring. Current lake CO2 flux estimates primarily rely on daylight measurements, yet nighttime emissions is normally overlooked. In this study, a non-dispersive infrared CO2 sensor was applied to measure dissolved CO2 concentrations over a 24-h period in a largest urban lake (Tangxun Lake) in Wuhan City, Central China, yielding extensive data on diel variability of CO2 concentrations and emissions. We showed the practicality and efficiency of the sensor for real-time continuous measurements in lakes. Our findings revealed distinct diurnal variations in CO2 concentrations (Day: 38.58 ± 23.8 µmol L-1; Night: 42.01 ± 20.2 µmol L-1) and fluxes (Day: 7.68 ± 10.34 mmol m-2 d-1; Night: 9.68 ± 9.19 mmol m-2 d-1) in the Tangxun Lake. The balance of photosynthesis and respiration is of utmost importance in modulating diurnal CO2 dynamics and can be influenced by nutrient loadings and temperature. A diel variability correction factor of 1.14 was proposed, suggesting that daytime-only measurements could underestimate CO2 emissions in urban lakes. Our data suggested that samplings between 11:00 and 12:00 could better represent the average diel CO2 fluxes. This study offered valuable insights on the diel variability of CO2 fluxes, emphasizing the importance of in situ continuous measurements to accurately quantify CO2 emissions, facilitating selections of sampling strategies and formulation of management strategies for urban lakes.

Insights into priming effects of dissolved organic matter degradation in urban lakes with different trophic states.

Priming effect (PE) is recognized as an important potential mechanism for dissolved organic matter (DOM) degradation in aquatic ecosystems. However, the priming effects (PEs) of various priming substances on the degradation of DOM pools in urban lakes along diverse trophic states remain unknown. To address this knowledge gap, the PEs and drivers of glucose and plant leachate of lake water with three trophic states were investigated. We reveal differences in the bioavailability of DOM in lake water, glucose, and plant leachate. The PE of the same priming substance was significantly higher in highly-eutrophic lake water than in mesotrophic lake. The priming intensity induced by glucose was significantly higher when compared to plant leachate. Regarding the addition of glucose, humic-like components (C1 and C3) showed slight PE, while the tyrosine-like component C2 showed negative PE. However, the positive PEs were observed on three components after adding plant leachate. The driver of PE by glucose shifted from nutrients to DOM components with increasing trophic levels. The PEs induced by plant leachate were affected by nutrients, chlorophyll-a (Chl-a), water chemistry, and DOM components in lightly/moderately-eutrophic lake water. This study revealed the intensities, directions, and drivers of PEs, providing essential insights into uncovering the DOM biogeochemical process in urban lakes.

Unsupervised domain adaptation for automated knee osteoarthritis phenotype classification.

Background: Osteoarthritis (OA) is a global healthcare problem. The increasing population of OA patients demands a greater bandwidth of imaging and diagnostics. It is important to provide automatic and objective diagnostic techniques to address this challenge. This study demonstrates the utility of unsupervised domain adaptation (UDA) for automated OA phenotype classification. Methods: We collected 318 and 960 three-dimensional double-echo steady-state magnetic resonance images from the Osteoarthritis Initiative (OAI) dataset as the source dataset for phenotype cartilage/meniscus and subchondral bone, respectively. Fifty three-dimensional turbo spin echo (TSE)/fast spin echo (FSE) MR images from our institute were collected as the target datasets. For each patient, the degree of knee OA was initially graded according to the MRI Knee Osteoarthritis Knee Score before being converted to binary OA phenotype labels. The proposed four-step UDA pipeline included (I) pre-processing, which involved automatic segmentation and region-of-interest cropping; (II) source classifier training, which involved pre-training a convolutional neural network (CNN) encoder for phenotype classification using the source dataset; (III) target encoder adaptation, which involved unsupervised adjustment of the source encoder to the target encoder using both the source and target datasets; and (IV) target classifier validation, which involved statistical analysis of the classification performance evaluated by the area under the receiver operating characteristic curve (AUROC), sensitivity, specificity and accuracy. We compared our model on the target data with the source pre-trained model and the model trained with the target data from scratch. Results: For phenotype cartilage/meniscus, our model has the best performance out of the three models, giving 0.90 [95% confidence interval (CI): 0.79-1.02] of the AUROC score, while the other two model show 0.52 (95% CI: 0.13-0.90) and 0.76 (95% CI: 0.53-0.98). For phenotype subchondral bone, our model gave 0.75 (95% CI: 0.56-0.94) at AUROC, which has a close performance of the source pre-trained model (0.76, 95% CI: 0.55-0.98), and better than the model trained from scratch on the target dataset only (0.53, 95% CI: 0.33-0.73). Conclusions: By utilising a large, high-quality source dataset for training, the proposed UDA approach enhances the performance of automated OA phenotype classification for small target datasets. As a result, our technique enables improved downstream analysis of locally collected datasets with a small sample size.

Intense methane diffusive emissions in eutrophic urban lakes, Central China.

Urban lakes are hotspots of methane (CH4) emissions. Yet, actual field measurements of CH4 in these lakes are rather limited and our understanding of CH4 response to urban lake eutrophication is still incomplete. In this study, we measured dissolved CH4 concentrations and quantified CH4 diffusion from four urban lakes in subtropical China during wet and dry seasons. We found that these lakes were constantly CH4-saturated, contributing the greenhouse gas (GHG) to the atmosphere. Nutrient enrichment significantly increased CH4 concentrations and diffusive fluxes. Average CH4 flux rate in the highly-eutrophic lake zones (4.18 ± 7.68 mmol m-2 d-1) was significantly higher than those in the mesotrophic (0.19 ± 0.18 mmol m-2 d-1) and lightly/moderately-eutrophic zones (0.72 ± 2.22 mmol m-2 d-1). Seasonally, CH4 concentrations and fluxes were significantly higher in the wet season than in the dry season in the mesotrophic and the lightly/moderately-eutrophic lake zones, but an inverse pattern existed in the highly-eutrophic lake zones. CH4 concentrations and fluxes increased with elevated levels of nitrogen, phosphorus and dissolved organic carbon (DOC). The accumulation of nutrients provided autochthonous substrate for methanogenesis, indicated by a negative correlation between CH4 and the C:N ratio. Ammonium-nitrogen (NH4+-N) was the best predictor for spatial fluctuation of CH4 concentrations and diffusive fluxes in the mesotrophic and the lightly/moderately-eutrophic lake zones, while total nitrogen (TN) and total phosphorus (TP) levels showed the highest predictability in the highly-eutrophic lake zones. Based on the findings, we conclude that nutrient enrichment in urban lakes can largely increase CH4 diffusion, and that urban sewage inflow is a key concern for eutrophication boosting CH4 production and diffusive emission. Furthermore, our study reveals that small urban lakes may be an important missing source of GHG emissions in the global C accounting, and that the ratio of littoral-to-pelagic zones can be important for predicting lake-scale estimation of CH4 emission.

Changes in CO2 concentration and degassing of eutrophic urban lakes associated with algal growth and decline.

Urban lakes are numerous in the world, but their role in carbon storage and emission is not well understood. This study aimed to answer the critical questions: How does algal growing season influence carbon dioxide concentration (cCO2) and exchange flux (FCO2) in eutrophic urban lakes? We investigated trophic state, seasonality of algal productivity, and their association with CO2 dynamics in four urban lakes in Central China. We found that these lightly-to moderately-eutrophic urban lakes showed a shifting pattern of CO2 source-sink dynamics. In the non-algal bloom phase, the moderately-eutrophic lakes outgassed on average of 12.18 ± 24.37 mmol m-2 d-1 CO2; but, during the algal bloom phase, the lakes sequestered an average 1.07 ± 6.22 mmol m-2 d-1 CO2. The lightly-eutrophic lakes exhibited lower CO2 emission in the algal bloom (0.60 ± 10.24 mmol m-2 d-1) compared to the non-algal bloom (3.84 ± 12.38 mmol m-2 d-1). Biological factors such as Chl-a (chlorophyll a) and AOU (apparent oxygen utilization), were found to be important factors to potentially affect the shifting pattern of lake CO2 source-sink dynamics in moderately-eutrophic lakes, explaining 48% and 34% of the CO2 variation in the non-algal and algal bloom phases, respectively. Moreover, CO2 showed positive correlations with AOU, and negative correlations with Chl-a in both phases. In the lightly-eutrophic lakes, biological factors explained a higher proportion of CO2 variations (29%) in the non-algal bloom phase, with AOU accounting for 19%. Our results indicate that algal growth and decline phases largely affect dissolved CO2 level and exchange flux by regulating in-lake respiration and photosynthesis. Based on the findings, we conclude that shallow urban lakes can act as both sources and sinks of CO2, with algal growth seasonality and trophic state playing pivotal roles in controlling their carbon dynamics.

H/D Exchange Coupled with 2H-labeled Stable Isotope-Assisted Metabolomics Discover Transformation Products of Contaminants of Emerging Concern.

Stable isotope-assisted metabolomics (SIAM) is a powerful tool for discovering transformation products (TPs) of contaminants. Nevertheless, the high cost or lack of isotope-labeled analytes limits its application. In-house H/D (hydrogen/deuterium) exchange reactions enable direct 2H labeling to target analytes with favorable reaction conditions, providing intuitive and easy-to-handle approaches for environmentally relevant laboratories to obtain cost-effective 2H-labeled contaminants of emerging concern (CECs). We first combined the use of in-house H/D exchange and 2H-SIAM to discover potential TPs of 6PPD (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine), providing a new strategy for finding TPs of CECs. 6PPD-d9 was obtained by in-house H/D exchange with favorable reaction conditions, and the impurities were carefully studied. Incomplete deuteride, for instance, 6PPD-d8 in this study, constitutes a major part of the impurities. Nevertheless, it has few adverse effects on the 2H-SIAM pipeline in discovering TPs of 6PPD. The 2H-SIAM pipeline annotated 9 TPs of 6PPD, and commercial standards further confirmed the annotated 6PPDQ (2-anilino-5-(4-methylpentan-2-ylamino)cyclohexa-2,5-diene-1,4-dione) and PPPD (N-phenyl-p-phenylenediamine). Additionally, a possible new formation mechanism for 6PPDQ was proposed, highlighting the performance of the strategy. In summary, this study highlighted a new strategy for discovering the TPs of CECs and broadening the application of SIAM in environmental studies.

Qualitative and quantitative studies on chemical constituents of Ling-gui-zhu-gan decoction: In vitro and in vivo.

Ling-gui-zhu-gan decoction has significant therapeutic effects in the treatment of diseases related to phlegm and fluid retention. In this study, we aimed to qualitatively characterize the chemical constituents of Ling-gui-zhu-gan decoction in vitro and in vivo by HPLC coupled to Fourier transform ion cyclotron resonance MS, and quantitively determine the contents of typical chemical constituents by HPLC method. As a result, a total of 75 chemical constituents were discovered including 37 flavonoids and their glycosides, 20 saponins, 9 sterols, 3 organic acids and their derivatives, 3 lactones, 2 coumarins, and 1 alcohol. Among them, 17 chemical constituents were specifically identified. Subsequently, an HPLC method was established for simultaneous determination of seven chemical constituents. Finally, a total of 40 prototype components were initially detected by HPLC-MS method in the biological samples of rats after their water extract was orally administrated. Among them, 29, 27, 12, and 32 prototype components were detected in plasma, bile, urine, and feces, respectively. Moreover, 34 metabolites, including 16 phase II metabolites, were detected for the first time. In conclusion, this study lays the foundation for the identification of chemical components in vitro and in vivo and the elucidation of the potential pharmacodynamic components of Ling-gui-zhu-gan decoction.

Nitrogen addition effect overrides warming effect on dissolved CO2 and phytoplankton structure in shallow lakes.

Shallow lakes are numerous in all climate zones, but our knowledge about their dissolved carbon dioxide (CO2) response to future climate change and nutrient enrichment is rather limited. Here we performed a mesocosm experiment with four treatments to investigate how warming and nitrogen addition will impact the partial pressure of CO2 (pCO2) and phytoplankton community individually and combined. We found that warming alone had no significant effect on pCO2, while nitrogen addition increased pCO2 significantly. The combined effects of nitrogen addition and warming on pCO2 level were prevalent, indicating that eutrophic shallow lakes would be double-jeopardized in the future climate. Warming and nitrogen addition together also showed to have changed the phytoplankton community structure, suggesting a potential shifting of biological system in shallow lakes under changing climate. These findings highlight the importance of reducing nitrogen pollution to shallow lake systems for sustainable development goal.

Interplant carbon and nitrogen transfers mediated by common arbuscular mycorrhizal networks: beneficial pathways for system functionality.

Arbuscular mycorrhizal fungi (AMF) are ubiquitous in soil and form nutritional symbioses with ~80% of vascular plant species, which significantly impact global carbon (C) and nitrogen (N) biogeochemical cycles. Roots of plant individuals are interconnected by AMF hyphae to form common AM networks (CAMNs), which provide pathways for the transfer of C and N from one plant to another, promoting plant coexistence and biodiversity. Despite that stable isotope methodologies (13C, 14C and 15N tracer techniques) have demonstrated CAMNs are an important pathway for the translocation of both C and N, the functioning of CAMNs in ecosystem C and N dynamics remains equivocal. This review systematically synthesizes both laboratory and field evidence in interplant C and N transfer through CAMNs generated through stable isotope methodologies and highlights perspectives on the system functionality of CAMNs with implications for plant coexistence, species diversity and community stability. One-way transfers from donor to recipient plants of 0.02-41% C and 0.04-80% N of recipient C and N have been observed, with the reverse fluxes generally less than 15% of donor C and N. Interplant C and N transfers have practical implications for plant performance, coexistence and biodiversity in both resource-limited and resource-unlimited habitats. Resource competition among coexisting individuals of the same or different species is undoubtedly modified by such C and N transfers. Studying interplant variability in these transfers with 13C and 15N tracer application and natural abundance measurements could address the eco physiological significance of such CAMNs in sustainable agricultural and natural ecosystems.

Agricultural ditches are hotspots of greenhouse gas emissions controlled by nutrient input.

Agricultural ditches are pervasive in agricultural areas and are potential greenhouse gas (GHG) hotspots, since they directly receive abundant nutrients from neighboring farmlands. However, few studies measure GHG concentrations or fluxes in this particular water course, likely resulting in underestimations of GHG emissions from agricultural regions. Here we conducted a one-year field study to investigate the GHG concentrations and fluxes from typical agricultural ditch systems, which included four different types of ditches in an irrigation district located in the North China Plain. The results showed that almost all the ditches were large GHG sources. The mean fluxes were 333 µmol m-2 h-1 for CH4, 7.1 mmol m-2 h-1 for CO2, and 2.4 µmol m-2 h-1 for N2O, which were approximately 12, 5, and 2 times higher, respectively, than that in the river connecting to the ditch systems. Nutrient input was the primary driver stimulating GHG production and emissions, resulting in GHG concentrations and fluxes increasing from the river to ditches adjacent to farmlands, which potentially received more nutrients. Nevertheless, the ditches directly connected to farmlands showed lower GHG concentrations and fluxes compared to the ditches adjacent to farmlands, possibly due to seasonal dryness and occasional drainage. All the ditches covered approximately 3.3% of the 312 km2 farmland area in the study district, and the total GHG emission from the ditches in this area was estimated to be 26.6 Gg CO2-eq yr-1, with 17.5 Gg CO2, 0.27 Gg CH4, and 0.006 Gg N2O emitted annually. Overall, this study demonstrated that agricultural ditches were hotspots of GHG emissions, and future GHG estimations should incorporate this ubiquitous but underrepresented water course.

[Hydrochemical Evolution in the Yarlung Zangbo River Basin].

In order to explore the hydro-chemical evolution law of the Yarlung Zangbo River Basin from 1973 to 2020, the hydro-chemical characteristics and major ion sources were studied using a Piper diagram, Gibbs diagram, ion ratio, and correlation analysis, and the irrigation applicability of the Yarlung Zangbo River was evaluated using the sodium adsorption ratio (SAR), sodium percentage (Na+%), and permeability index (PI). The results showed that the mean value of TDS was (208.30±58.26) mg·L-1, which increased with time. Ca2+ was the dominant cation, accounting for (65.49±7.67)% of the total cations. HCO-3 and SO2-4 were the dominant anions, accounting for (68.56±9.84)% and (26.85±9.82)% of the main anions, respectively. The annual growth rates of Ca2+, HCO-3, and SO2-4 were respectively 2.07, 3.19, and 4.70 mg·(L·10 a)-1. The hydro-chemical type of the Yarlung Zangbo River was HCO3-Ca type, and the main ionic chemistry was controlled by the chemical weathering of carbonate rocks. The weathering of carbonate rocks during the period of 1973 to 1990 was mainly controlled by carbonation, whereas from 2001 to 2020 it was mainly controlled by both carbonation and sulfuric acid. The main ion concentrations in the mainstream of Yarlung Zangbo River were within the range of drinking water standards, with SAR between 0.11-0.93, Na+% between 8.00-36.73, and PI values between 0.39-0.87, demonstrating that the waters were suitable for drinking and irrigation. The results were of great significance to the protection and sustainable development of water resources in the Yarlung Zangbo River Basin.