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Recent studies suggest that hypolimnetic respiration may be responsible for greenhouse gas (GHG) emissions from deep reservoirs. Currently, quantitative evaluation of aerobic vs. anaerobic processes and priming (enhanced processing of organic matter due to the addition of labile carbon) in regulating GHG production and emissions across the reservoir‐downstream continuum remains largely unknown. High‐resolution, annual time‐series observations in a large, subtropical reservoir (Shuikou) experiencing seasonal hypoxia in southeast China indicate that aerobic hypolimnetic CO2 production dominated in most periods of the stratified spring/summer with higher rates at higher temperatures. In addition, anaerobic production of hypolimnetic CO2 occurred in the late stratified spring/summer period, which stimulated hypolimnetic production of CH4 and N2O. Incubation experiments showed that priming in spring enhanced both aerobic and anaerobic production of excess GHGs. A late spring flood event generated the highest daily efflux of CO2 through the flushing of GHG‐enriched hypolimnion waters. Turbine degassing contributed 59%, 93%, and 63% of annual CO2, CH4, and N2O effluxes, respectively. Moreover, annual downstream GHG emissions were similar to those in the transition/lacustrine zone of the Shuikou reservoir. Diurnal variation observations revealed net CO2 emissions even during algal bloom seasons. The reservoir‐downstream river continuum was a year‐round source of GHGs (218.5 ± 18.9 Gg CO2‐equivalent yr−1; CO2 contributed 91%). However, the loss of oxygen also leads to increased production and storage of recalcitrant dissolved organic carbon (RDOC). Thus, identifying mechanisms controlling both GHG emissions and RDOC production is crucial to constrain the carbon neutrality issue of hydroelectric reservoirs in the context of climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

The Loess Plateau of China has witnessed a remarkable greening trend due to vegetation restoration in recent decades. However, the precipitation response to greening remains unclear, and the hydrological effect of greening is controversial. Here, we revisited biophysical effects of greening on precipitation over the plateau during 2002–2015 using the state‐of‐the‐art water vapor tracer embedded in a regional coupled model. We find that greening can promote the growing season precipitation (0.45 mm·day−1), with 15% and 85% of the precipitation increment resulting from increases in the local evapotranspiration and the water vapor inflow from outside the plateau, respectively. As a consequence, the enhanced precipitation can compensate for the terrestrial water loss driven by the increased evapotranspiration, leading to a slight increase in the water yield. This study highlights the dominant role of the nonlocal effect in precipitation responses to greening in this region. Plain Language Summary: In recent decades, the Loess Plateau of China has shown a significant greening trend due to vegetation restoration. In the meantime, greening tends to accelerate the terrestrial water loss via the enhanced evapotranspiration, leading to a decline in the terrestrial water storage. However, such an impact remains controversial because of large uncertainties in precipitation responses to greening. It remains unclear whether the precipitation response can alleviate or aggravate the surface water deficit due to the enhanced evapotranspiration following greening. In this study, we examine impacts of greening on precipitation over the plateau during 2002–2015 using a water vapor tracer embedded in a regional coupled model. The results show that greening can enhance precipitation, which can compensate for evapotranspiration‐driven water loss and consequently increase the water yield in the growing season. 85% of the precipitation increment results from the enhanced water vapor inflow outside the plateau due to responses of large‐scale circulations to greening. The water vapor originating from the enhanced evapotranspiration within the plateau only accounts for 15% of the precipitation increment. This study provides new insight into precipitation responses to greening and the mechanism over the plateau using water vapor tracing. Key Points: Biophysical impacts of greening on precipitation over the Loess Plateau are investigated based on WRF‐WVTGreening can promote the growing season precipitation, which can compensate for the evapotranspiration‐driven terrestrial water lossThe enhanced precipitation mainly results from enhanced water vapor inflow outside the plateau due to responses of circulations to greening [ABSTRACT FROM AUTHOR]

The annual precipitation in North China and South China shows a dipole pattern with a clear inter-decadal transition around the late 1970s. However, the relative contribution of internal variability and external forcing to this inter-decadal transition is still unclear. Here, we separate internal variability from the externally forced climate response through a set of dynamical downscaling simulations with lateral boundary conditions derived from reanalysis data and a large ensemble mean of the CMIP5 historical simulations. We find that internal variability accounts for about 65 and 55% of the inter-decadal transition of the annual precipitation in South and North China, respectively. By contrast, external forcing accounts for about 70% of the warming trend in eastern China over the second half of the 20th century. This study highlights the differential response of regional precipitation and air temperature to internal variability and external forcing over eastern China on an inter-decadal timescale. [ABSTRACT FROM AUTHOR]

The fast and accurate classification of surrounding rock mass is the basis for tunnel design and construction and has significant value in engineering applications. Therefore, this paper proposes a method for classifying and predicting surrounding rock mass based on particle swarm optimization (PSO)–least squares support vector machine (LSSVM). The premise of the research is that the data acquired from digital drilling technology are divided into a training group and a test group; the training group continuously optimizes the algorithm for the particle swarm optimization least squares support vector machine, and then the test group is used for verification. Moreover, the fast searching abilities of the particle swarm significantly accelerate the computational power and computational accuracy of the least squares support vector machine, making it a high-speed analog search tool. Taking the Jiaozhou Bay undersea tunnel in China as an example, a comparison of the evaluation results of PSO-LSSVM and QGA-RBF (quantum genetic algorithm-radical basis function neural network) is undertaken. The results show that PSO-LSSVM matches well with the field-measured surrounding rock grade. Applying the method in an engineering context proves that it has good self-learning abilities, even when the sample size is small and the prediction accuracy is high; as such, it meets the engineering requirements. The technique has the advantages of small sample prediction, pattern recognition, and nonlinear prediction. [ABSTRACT FROM AUTHOR]

Afforestation can impact surface temperature through local and nonlocal biophysical effects. However, the local and nonlocal effects of afforestation in China have rarely been explicitly investigated. In this study, we separate the local and nonlocal effects of idealized afforestation in China based on a checkerboard method and the regional Weather Research and Forecasting (WRF) Model. Two checkerboard pattern–like afforestation simulations (AFF1/4 and AFF3/4) with regularly spaced afforested and unaltered grid cells are performed; afforestation is implemented in one out of every four grid cells in AFF1/4 and in three out of every four grid cells in AFF3/4. The mechanisms for the local and nonlocal effects are examined through the decomposition of the surface energy balance. The results show that the local effects dominate surface temperature responses to afforestation in China, with a cooling effect of approximately −1.00°C for AFF1/4 and AFF3/4. In contrast, the nonlocal effects warm the land surface by 0.14°C for AFF1/4 and 0.41°C for AFF3/4. The local cooling effects mainly result from 1) enhanced sensible and latent heat fluxes and 2) decreases in downward shortwave radiation due to increased low cloud cover fractions. The nonlocal warming effects mainly result from atmospheric feedbacks, including 1) increases in downward shortwave radiation due to decreased low cloud cover fractions and 2) increases in downward longwave radiation due to increased middle and high cloud cover fractions. This study highlights that, despite the unexpected nonlocal warming effect, afforestation in China still has great potential in mitigating climate warming through biophysical processes. [ABSTRACT FROM AUTHOR]

Human brucellosis is caused by Brucella species and remains a major burden in both human and domesticated animal populations, especially in Inner Mongolia, China. The aims of this study were to analyze the spatiotemporal trends in human brucellosis in Inner Mongolia during 2010 to 2015, to explore the factors affecting the incidence of brucellosis. The results showed that the annual incidence was 29.68–77.67 per 100,000, and peaked from March to June. The majority of human brucellosis was male farmers and herdsmen, aged 40–59 years. The high-risk areas were mainly Xilin Gol League and Hulunbeier City. The incidence of human brucellosis in Inner Mongolia decreased during 2010 to 2015, although the middle and eastern regions were still high-risk areas. The regions with larger number of sheep and cattle, lower GDP per capita, less number of hospital beds, higher wind speed, lower mean temperature more likely to become high-risk areas of human brucellosis. [ABSTRACT FROM AUTHOR]

Regional climate models have been widely used to examine the biophysical effects of afforestation, but their performance in this respect has rarely been evaluated. To fill this knowledge gap, an evaluation method based on the "space for time" strategy is proposed here. Using this method, we validate the performance of three coupled regional models—the Regional Climate Model (RegCM), the Weather Research and Forecasting (WRF) Model, and the WRF Model run at a convection-permitting resolution (WRF-CP)—in representing the local biophysical effects of afforestation over continental China against satellite observations. The results show that WRF and WRF-CP cannot accurately describe afforestation-induced changes in surface biophysical properties (e.g., albedo or leaf area index). Second, all models exhibit poor simulations of afforestation-induced changes in latent and sensible heat fluxes. In particular, the observed increase in the summer latent heat due to afforestation is substantially underestimated by all models. Third, the models are basically reasonable in representing the biophysical impact of afforestation on temperature. The cooling of the daily mean surface temperature and 2-m temperature in summer are reproduced well. Nevertheless, the mechanism driving the cooling effect may be improperly represented by the models. Moreover, the models perform relatively poorly in representing the response of the daily minimum surface temperature to afforestation. These results highlight the necessity of evaluating the representation of the biophysical effects by a model before the model is employed to carry out afforestation experiments. This study serves as a test bed for validating regional model performance in this respect. [ABSTRACT FROM AUTHOR]

Oceanic absorption of heat generated by greenhouse gas emissions has resulted in warming of the dark ocean (>200 m) that contains a large refractory DOM (RDOM) pool. However, changes in microbially mediated production and degradation dynamics for RDOM components in response to warming of dark marginal basins remain unclear. Herein, we integrated data from the dark South China, Mediterranean and Japan Seas (temperature range: 0.09–15.1°C) to demonstrate that in situ production efficiency of two ubiquitous humic‐like fluorophores increased at higher dark ocean temperature, whereas chromophores at a wavelength of 325 nm (aCDOM(325)) changed from production to degradation at higher temperature. Increased oxygen consumption and a reduction of labile substrates in future warmer dark ocean environments may initiate the final degradation of some semi‐refractory components, thereby increasing the recalcitrance of RDOM, but decreasing the DOM inventory in dark basins and creating a positive feedback to rising atmospheric CO2. Plain Language Summary: Marine refractory dissolved organic matter (RDOM) in the dark ocean is primarily formed during heterotrophic degradation of labile organic matter, which has a pronounced sensitivity to temperature variation. Since the 1960s, the global dark ocean has exhibited an accelerated warming with a discernable temperature increase. Thus, determining the importance of temperature on microbial regulation of the oceanic RDOM pool is of great significance. This study utilized the ocean interior of the marginal South China, Mediterranean and Japan Seas as natural basin‐scale enclosed incubators along with optical DOM characterization methods to reveal a production‐degradation reaction series for RDOM components. A decrease in the DOM inventory by enhanced microbial mineralization (producing CO2) in a warmer dark ocean may create a positive feedback in response to global climate change. Key Points: Faster turnover for optical components of dissolved organic matter (DOM) was observed in dark marginal basins than in the open oceanIn situ production efficiency of two ubiquitous humic‐like fluorophores increased at higher dark ocean temperaturesAn increase of DOM recalcitrance and decrease of the bulk dissolved organic carbon pool may occur due to a future warming of dark basins [ABSTRACT FROM AUTHOR]

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Soil moisture (SM) plays a critical role in the water and energy cycles of the Earth system; consequently, a long-term SM product with high quality is urgently needed. In this study, five SM products, including one microwave remote sensing product – the European Space Agency's Climate Change Initiative (ESA CCI) – and four reanalysis data sets – European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis – Interim (ERA-Interim), National Centers for Environmental Prediction (NCEP), the 20th Century Reanalysis Project from National Oceanic and Atmospheric Administration (NOAA), and the ECMWF Reanalysis 5 (ERA5) – are systematically evaluated using in situ measurements during 1981–2013 in four climate regions at different timescales over the Chinese mainland. The results show that ESA CCI is closest to the observations in terms of both the spatial distributions and magnitude of the monthly SM. All reanalysis products tend to overestimate soil moisture in all regions but have higher correlations than the remote sensing product except in Northwest China. The largest inconsistency is found in southern Northeast China region, with an unbiased root mean square error (ubRMSE) value larger than 0.04. However, all products exhibit certain weaknesses in representing the interannual variation in SM. The largest relative bias of 144.4 % is found for the ERA-Interim SM product under extreme and severe wet conditions in northeastern China, and the lowest relative bias is found for the ESA CCI SM product, with the minimum of 0.48 % under extreme and severe wet conditions in northwestern China. Decomposing mean square errors suggests that the bias terms are the dominant contribution for all products, and the correlation term is large for ESA CCI. As a result, the ESA CCI SM product is a good option for long-term hydrometeorological applications on the Chinese mainland. ERA5 is also a promising product, especially in northern and northwestern China in terms of low bias and high correlation coefficient. This long-term intercomparison study provides clues for SM product enhancement and further hydrological applications. [ABSTRACT FROM AUTHOR]

It is well recognized that dam construction aggravates eutrophication and hypoxia in river reservoirs, but the interaction between oxygen dynamics and carbon cycling is often unclear. Here we investigated the external and internal controls on oxygen consumption and effects of hypoxia on carbon dioxide (CO2) emission in a subtropical reservoir in southeast China based on detailed field measurements during 2017 and 2018. Hypoxia lasted 4 months starting in mid‐July and expanded from the bottom to near surface water. Rainstorm hyperpycnal flow and unusual hydraulics (outflow exit 40 m from the bottom) resulted in two thermoclines and enhanced the oxygen deficit in deeper water. Microbial respiration accounted for 67.4%–96.5% of total oxygen consumption in the bottom water. The increased supply of organic matter from storm runoff and to a lesser extent primary production in summer enhanced subsequent oxygen consumption. We observed an imbalance between excess CO2 production and oxygen depletion in summer and winter which was likely associated with other processes in the hypolimnion (e.g., chemoautotrophy, anaerobic degradation of organic matter, proton buffering, and nitrification). The water‐air CO2 fluxes suggest that the surface reservoir usually served as a CO2 source, but was a sink in summer due to high primary productivity. CO2 was always oversaturated in the hypolimnion; this layer was at the depth of the dam outflow and ultimately released 68% of annual CO2 efflux to the atmosphere. This research confirmed that construction of a hydropower dam has substantially altered reservoir metabolism and regulated the CO2 emission pathway. Key Points: Storm flow and external organic matter cause two thermoclines and 4‐month long hypoxiaOxygen consumption and carbon dioxide emission are imbalanced in summer and winterBoth the reservoir and downstream outflow are a net source of CO2 to the atmosphere [ABSTRACT FROM AUTHOR]

Using Weather Research and Forecasting (WRF) model, we perform the first dynamic downscaling of Community Earth System Model (CESM) Low‐Warming simulations to examine hot extreme changes over China in response to stabilized 1.5°C and 2°C global warming. WRF projects more intense and frequent hot extremes due to global warming, which are qualitatively consistent with CESM. However, WRF and CESM significantly differ in magnitudes of hot extreme changes. Compared to CESM, WRF indicates larger increases in hot extremes over Tibetan Plateau but smaller increases over other regions. Such differences between WRF and CESM are mainly caused by divergent projections of shortwave radiation changes. WRF also suggests fewer benefits achieved from the additional 0.5°C warming constraint than CESM. This study demonstrates the climate risks might be inadequately informed by global climate models and it is necessary to reevaluate impacts of 1.5°C and 2°C global warming on regional climate based on regional climate models. Plain Language Summary: Regional climate models (RCMs) are generally more superior than global climate models (GCMs) in climate modeling and projection at regional scales. Using a RCM, we examine the future hot extreme changes over China in response to the global warming being stabilized at 1.5°C and 2°C level by the end of the 21st century. We also compare the result from the RCM with that from a GCM. The RCM and GCM both indicate China will suffer from more intense and frequent hot extreme events due to the 1.5°C and 2°C warming. However, the magnitudes of hot extreme changes are significantly different between the two models. Specifically, the RCM indicates higher risks of hot extremes over Tibetan Plateau and lower risks over other regions than the GCM. Compared to the GCM, the RCM also indicates that fewer benefits can be achieved from the additional 0.5°C warming. Key Points: Impacts of stabilized 1.5°C and 2°C global warming on hot extremes over China are examined based on dynamic downscalingDynamic downscaling can significantly modify the projection of hot extreme changes in response to the 1.5°C and 2°C warmingThe downscaling induced differences in hot extremes changes are mainly attributed to the modification of shortwave radiation changes [ABSTRACT FROM AUTHOR]

Background: 5G communication technology has been applied to several fields in telemedicine, but its effectiveness, safety, and stability in remote laparoscopic telesurgery have not been established. Here, we conducted four ultra-remote laparoscopic surgeries on a swine model under the 5G network. The aim of the study was to investigate the effectiveness, safety, and stability of the 5G network in remote laparoscopic telesurgery.Methods: Four ultra-remote laparoscopic surgeries (network communication distance of nearly 3000 km), including left nephrectomy, partial hepatectomy, cholecystectomy, and cystectomy, were performed on a swine model with a 5G wireless network connection using a domestically produced "MicroHand" surgical robot. The average network delay, operative time, blood loss, and intraoperative complications were recorded.Results: Four laparoscopic telesurgeries were safely performed through a 5G network, with an average network delay of 264 ms (including a mean round-trip transporting delay of 114 ms and a 1.20% data packet loss ratio). The total operation time was 2 h. The total blood loss was 25 ml, and no complications occurred during the procedures.Conclusions: Ultra-remote laparoscopic surgery can be performed safely and smoothly with 5G wireless network connection using domestically produced equipment. More importantly, our model can provide insights for promoting the future development of telesurgery, especially in areas where Internet cables are difficult to lay or cannot be laid. [ABSTRACT FROM AUTHOR]

The 2015/2016 super El Niño event resulted in a positive precipitation anomaly during dry seasons in the Jiulong River watershed, southeast China. Four years (2014–2017) of high frequency, in situ humic‐like fluorescent DOM (FDOMH) data in the Jiulong Estuary were coupled with extrapolation to a freshwater end‐member FDOMH concentration and river discharge data to estimate riverine FDOMH export. The wetter El Niño dry season was followed by lower FDOMH export during the subsequent wet season. Furthermore, in the dry season after El Niño reached its strongest phase, a 90–187% increase in FDOMH export occurred. If widespread, this pattern suggests El Niño events may enhance export of FDOMH from south China rivers in dry seasons resulting in seasonal and annual shunting of the terrestrial DOM export, modulating coastal carbon cycling. This study highlights the need to incorporate climate‐driven regulation patterns on DOM transport across the land‐ocean interface. Key Points: 2015/2016 El Niño event induced a positive precipitation anomaly that increased FDOMH export during dry seasons from a subtropical watershedThe wetter El Niño dry season was followed by lower FDOMH export during the subsequent wet seasonWatershed processes buffered FDOMH export relative to the El Niño‐induced increase of precipitation/discharge [ABSTRACT FROM AUTHOR]

To resolve a series of ecological and environmental problems over the Loess Plateau, the "Grain for Green Program" (GFGP) was initiated at the end of 1990s. Following the conversion of croplands and bare land on hillslopes to forests, the Loess Plateau has displayed a significant greening trend, which has resulted in soil erosion being reduced. However, the GFGP has also affected the hydrology of the Loess Plateau, which has raised questions regarding whether the GFGP should be continued in the future. We investigated the impact of revegetation on the hydrology of the Loess Plateau using relatively high-resolution simulations and multiple realizations with the Weather Research and Forecasting (WRF) model. Results suggest that revegetation since the launch of the GFGP has reduced runoff and soil moisture due to enhanced evapotranspiration. Further revegetation associated with the GFGP policy is likely to further increase evapotranspiration, and thereby reduce runoff and soil moisture. The increase in evapotranspiration is associated with biophysical changes, including deeper roots that deplete deep soil moisture stores. However, despite the increase in evapotranspiration, our results show no impact on rainfall. Our study cautions against further revegetation over the Loess Plateau given the reduction in water available for agriculture and human settlements and the lack of any significant compensation from rainfall. [ABSTRACT FROM AUTHOR]

China is several decades into large-scale afforestation programs to help address significant ecological and environmental degradation, with further afforestation planned for the future. However, the biophysical impact of afforestation on local surface temperature remains poorly understood, particularly in midlatitude regions where the importance of the radiative effect driven by albedo and the nonradiative effect driven by energy partitioning is uncertain. To examine this issue, we investigated the local impact of afforestation by comparing adjacent forest and open land pixels using satellite observations between 2001 and 2012. We attributed local surface temperature change between adjacent forest and open land to radiative and nonradiative effects over China based on the Intrinsic Biophysical Mechanism (IBM) method. Our results reveal that forest causes warming of 0.23°C (±0.21°C) through the radiative effect and cooling of −0.74°C (±0.50°C) through the nonradiative effect on local surface temperature compared with open land. The nonradiative effect explains about 79% (±16%) of local surface temperature change between adjacent forest and open land. The contribution of the nonradiative effect varies with forest and open land types. The largest cooling is achieved by replacing grasslands or rain-fed croplands with evergreen tree types. Conversely, converting irrigated croplands to deciduous broadleaf forest leads to warming. This provides new guidance on afforestation strategies, including how these should be informed by local conditions to avoid amplifying climate-related warming. [ABSTRACT FROM AUTHOR]

Abstract: Dissolved organic matter (DOM) has not been studied fully for tropical and subtropical rivers, in particular during storm events. DOM dynamics during a summer storm event in June, 2011 were examined in a subtropical river (the North Jiulong River, China). Stormwater runoff was sampled for measurement of dissolved organic C (DOC), absorption spectroscopy and fluorescence excitation emission matrix spectroscopy (EEMs). Three different fluorescent components were identified using parallel factor analysis (PARAFAC), including humic-like C1 and C3, and C2 as a combination of humic-like and protein-like fluorophores. The flux of DOC increased fivefold from 0.4kgs−1 at baseflow to 2.0kgs−1 at peak flow. Chromophoric DOM (CDOM) and fluorescent components also showed large increases with stormflow. The flux of DOC was similar during the rising and falling hydrographs at equal water discharge, while those of CDOM and fluorescent components were much higher during the falling-hydrograph. Carbon specific CDOM absorption coefficient at UV (SUVA254) and the fraction of C3 which fluoresced at long emission wavelength correlated positively to each other but negatively to absorption spectral slope ratio (S R) and C2%. They showed notable temporal variations indicative of increases in aromaticity, C3% and average molecular weight of DOM during the storm event. Changes in DOM composition lagged behind those in DOM flux. Changes in the flux and quality of DOM during the storm event, which were monitored effectively by absorption spectroscopy and EEMs–PARAFAC, could affect biogeochemical processes in the river and receiving coastal waters. [Copyright &y& Elsevier]

Dissolved organic matter (DOM) was characterized during five basin-scale investigations (either after storms or in droughts) in Jiulong River, China that is affected by the Asian Monsoon, tropical storms and anthropogenic activities. Dissolved organic carbon concentration, DOM absorption and fluorescence (excitation-emission matrix spectra, EEMs) were measured. Parallel factor analysis (PARAFAC) of EEMs identified three humic-like and two protein-like fluorescent components. DOM concentration was highest at two polluted stations in droughts while lowest in pristine headwaters (station N1). DOM concentration increased most evidently after storms in May, 2009, indicating effective flushing of DOM from land to the river close to the onset of flood season. The protein-like fraction in PARAFAC results decreased after storms in May and June, 2009, highlighting changes in DOM composition and thus its environmental role. Dam constructions likely increased the residence time of DOM in river, making the inflow of DOM during storms have more implications for the riverine (in comparison with estuarine) biogeochemical processes. The effect of storm in August, 2008 after intense DOM flushing during several preceding storms, was not evident. A severe dinoflagellate algal bloom occurred during the extreme drought in the lower watershed, which increased DOM concentration and the protein-like fraction at impacted stations. Different DOM compositions during and after algal bloom were discriminated using the two protein-like components. This study demonstrates the importance of hydrologic regimes and anthropogenic activities on freshwater DOM and its environmental role, which has implications for a number of other rivers that share similar characteristics. [ABSTRACT FROM AUTHOR]

The composition of dissolved organic matter (DOM) is an important determinant for its biogeochemical role in the aquatic environments. Therefore, it is crucial to determine the effects of changing land use on the DOM composition in the river watershed. Water samples were collected from the outlets of 15 sub-watersheds in the subtropical Jiulong River (southeast China) for fluorescence measurements and parallel factor analysis. Two humic-like (C1 and C2) and one protein-like (C3) fluorescent components were identified. Overall, DOM in the Jiulong River watershed was dominated by humic-like materials, probably due to the fact that 69% of the watershed is covered with forest. The 15 sub-watersheds were grouped into four clusters based on the proportion of each fluorescent component in the total fluorescence, suggesting that the DOM composition could be very different among sub-watersheds. There was a strong negative correlation between C2 and C3%. C1% correlated with the water body fraction, likely associated with the aquatic production of C1. C3% correlated positively with the residential area fraction, likely indicating the influence of anthropogenic activities. These results are useful for assessing the effects of land use/land cover changes on the composition and hence biogeochemical roles of DOM in aquatic environments. [ABSTRACT FROM AUTHOR]

In this study, a new parameter optimization method was used to investigate the expansion of conditional nonlinear optimal perturbation (CNOP) in a land surface model (LSM) using long-term enhanced field observations at Tongyu station in Jilin Province, China, combined with a sophisticated LSM (common land model, CoLM). Tongyu station is a reference site of the international Coordinated Energy and Water Cycle Observations Project (CEOP) that has studied semiarid regions that have undergone desertification, salination, and degradation since late 1960s. In this study, three key land-surface parameters, namely, soil color, proportion of sand or clay in soil, and leaf-area index were chosen as parameters to be optimized. Our study comprised three experiments: First, a single-parameter optimization was performed, while the second and third experiments performed triple- and six-parameter optimizations, respectively. Notable improvements in simulating sensible heat flux (SH), latent heat flux (LH), soil temperature (TS), and moisture (MS) at shallow layers were achieved using the optimized parameters. The multiple-parameter optimization experiments performed better than the single-parameter experminent. All results demonstrate that the CNOP method can be used to optimize expanded parameters in an LSM. Moreover, clear mathematical meaning, simple design structure, and rapid computability give this method great potential for further application to parameter optimization in LSMs. [ABSTRACT FROM AUTHOR]

Abstract: The spectral absorption properties of chromophoric dissolved organic matter (CDOM) and their distributions in two Chinese estuaries, the Yangtze River Estuary and the Jiulong River Estuary, were studied during August 2003 (wet season) and during different seasons between 2003−2005, respectively. The CDOM concentrations (a 355) of fresh end members in the Jiulong River Estuary varied seasonally, while its quality remained relatively stable. However, the a 355 of the marine end members exhibited less variability. Application of a conservative mixing model indicated that CDOM behaved conservatively in the Yangtze River Estuary. No photobleaching removal was observed at high salinity region of this estuary. Although CDOM showed conservative behavior for many cruises in the Jiulong River Estuary, there was evidence for removal in the low salinity regions during some cruises. Laboratory mixing experiments and a salt addition experiment suggested that particle sorption of CDOM maybe the possible reason for the removal. These results showed that absorption properties of CDOM can be used as a tool to observe the quantitative and qualitative dynamics of DOM during estuarine mixing. [Copyright &y& Elsevier]

Background: Tuberculosis (TB) is an important public health issue worldwide. However, evidence concerning the impact of environmental factors on TB is sparse. We performed a retrospective analysis to determine the spatiotemporal trends and geographic variations of, and the factors associated with, the TB prevalence in Inner Mongolia.Methods: We performed a retrospective analysis of the epidemiology of TB. A Bayesian spatiotemporal model was used to investigate the spatiotemporal distribution and trends of the TB prevalence. A spatial panel data model was used to identify factors associated with the TB prevalence in the 101 counties of Inner Mongolia, using county-level aggregated data collected by the Inner Mongolia Center for Disease Control and Prevention.Results: From January 2010 to December 2014, 79,466 (6.36‱) incident TB cases were recorded. The TB prevalence ranged from 4.97‱ (12,515/25,167,547) in 2014 to 7.49‱ (18,406/ 24,578,678) in 2010; the majority of TB cases were in males, and in those aged 46-60 years; by occupation, farmers and herdsmen were the most frequently affected. The Bayesian spatiotemporal model showed that the overall TB prevalence decreased linearly from 2010 to 2014 and occupation-stratified analyses yielded similar results, corroborating the reliability of the findings. The decrease of TB prevalence in the central-western and eastern regions was more rapid than that in the overall TB prevalence. A spatial correlation analysis showed spatial clustering of the TB prevalence from 2011 to 2014 (Moran's index > 0, P < 0.05); in the spatial panel data model, rural residence, birth rate, number of beds, population density, precipitation, air pressure, and sunshine duration were associated with the TB prevalence.Conclusions: The overall TB prevalence in Inner Mongolia decreased from 2010 to 2014; however, the incidence of TB was high throughout this period. The TB prevalence was influenced by a spatiotemporal interaction effect and was associated with epidemiological, healthcare, and environmental factors. [ABSTRACT FROM AUTHOR]

Blueberry plant (Vaccinium spp.) roots are sensitive to pH changes (> 5.5) in the rhizosphere. In China, the soil pH in blueberry planting areas is typically above 5.5, consequently restricting industry expansion. Root plasma membrane proton pumps (PM H+-ATPase - HAs) promote the efflux of H+ during nutrient absorption, thereby reducing stress associated with alkaline rhizosphere soils. However, the regulatory mechanisms governing expression of blueberry VcHAs genes are unknown. We isolated promoter fragments upstream of the translational start of nine VcHA genes from Vaccinium spp. Based on the strength of transient promoter::luc expression in tobacco leaves, VcHA11.1- prom was selected for further analyses of cis -acting elements and transcription factors (TFs). In silico and in vitro (yeast one-hybrid - Y1H) studies with a 5-prime deletion VcHA11.1- prom variant (B) were used to identify and verify binding of two blueberry TFs, namely VcDof2.1 and VcbHLH104. Ensuing transient Luc assays in transgenic tobacco leaves revealed that VcbHLH104 upregulated and VcDof2.1 downregulated expression from VcHA11.1 -B-prom. qRT-PCR analysis of RNA isolated from WT blueberry roots confirmed that plants propagated at pH 5.0 resulted in high VcDof2.1 but low VcHA11.1 transcripts. VcbHLH104 transcript levels significantly increased (ca. 242.0%) and paralleled those of VcHA11.1 when plants were cultivated at pH 7.0. Transgenic Arabidopsis seedlings overexpressing VcbHLH104 demonstrated improved H+ efflux and alleviated stress at pH ≥ 7.0 with no distinguishable plant etiolation. Conversely, transgenic plants expressing VcDof2.1 displayed weak H+ release, poor growth, leaf sparsity and chlorosis at pH ≥ 7.0. We conclude that expression of VcHA11.1 is pH dependent and that promoter transcription is counter regulated by VcDof2.1 and VcbHLH104 at pH ≤ 5.0 and pH ≥ 7.0, respectively. • Nine VcHA gene promoters from Vaccinium spp. isolated and characterized. • First reported isolation of TFs which regulate VcHAs promoters. • VcbHLH104 TF positively activated expression from VcHA11.1 promoter. • VcDof2.1 TF down regulated expression from the VcHA11.1 promoter. • Transgenic Arabidopsis overexpressing VcbHLH104 improved H+ efflux and alleviated pH stress. [ABSTRACT FROM AUTHOR]

[Display omitted] • An on-line automated method was developed for monitoring trace Cu(Ⅱ) in seawater. • The method possessed low detection limit and wide linear range. • The method was free of the carry-over effect and interference of nine co-existing ions. • Field applications were successfully carried out to prove the method practicability. By using reverse flow injection analysis (rFIA) and a 1.0 m liquid waveguide capillary cell (LWCC), an automatic and sensitive catalytic kinetic spectrophotometric method for on-line monitoring of Cu(II) concentrations in estuarine and coastal waters was established. Cu(II) detection was based on its catalytic effect on glutathione (GSH) oxidation by potassium ferricyanide under acidic conditions. The change in absorbance of potassium ferricyanide at 420 nm was used to monitor the reaction spectrophotometrically. Experimental parameters were optimized using a univariate experimental design approach and it was ensured that the method was free of interference from co-occurring ions such as Fe(Ⅱ), Fe(III), Mn, Zn, Cd, Al, Cr, Ni and Co. The proposed method was shown to have high sensitivity with a detection limit of 0.15 nmol L-1 in a pure water matrix and 0.23 nmol L-1 in a seawater matrix. Linearity was achieved within the range of 0.45–15 nmol L-1 in a pure water matrix and 0.69–10 nmol L-1 in a seawater matrix using a 200 cm reaction coil, while the upper limits can be extended to 40 and 25 nmol L-1, respectively, by using a shorter (100 cm) reaction coil. A high level of Cu(II) recovery was maintained, ranging between 95.2% and 101%. The relative standard deviations (RSDs) of blanks and samples spiked with 5 nmol L-1 Cu(II) standard were 1.52% (n = 13) and 1.10% (n = 13), respectively. The method was confirmed to be free of carry-over effect and a sample throughput of 26 h−1 was achieved. The method was successfully applied to underway and on-board determination of Cu(II) concentrations from a surface transect in the Jiulong Estuary and a vertical profile in the Yangtze Estuary, China, respectively. [ABSTRACT FROM AUTHOR]

• DOM sources and transformations were investigated along a river-reservoir continuum. • Deoxygenation enhanced hypolimnetic refractory DOM production and lateral export. • Inland dark waters are hotspots for microbial carbon transformation and turnover. Global impoundment of river systems represents a major anthropogenic forcing to carbon cycling in reservoirs with seasonal thermal stratification. Currently, a quantitative and mechanistic understanding of how hypolimnetic deoxygenation in stratified reservoirs alters dissolved organic matter (DOM) cycling and lateral transport along the river continuum remains unresolved. Herein, we used optical and high-resolution mass spectrometric analyses to track seasonal and spatial compositional changes of DOM from a large, subtropical impounded river in southeast China. Aliphatic compounds were contributed by algal blooms to epilimnetic DOM during the spring/summer and by baseflow to the overall DOM pool during low-discharge periods. Deoxygenation-driven hypolimnetic mineralization enhanced in situ production of bio-refractory molecules and humic-like fluorescent DOM (FDOM H) by utilizing bio-labile DOM and settling biogenic particles during periods of stratification. Production efficiency of hypolimnetic FDOM H was 159–444% higher than that of the global dark ocean, and was strongly regulated by temperature and possibly substrate supply. The in situ production rate of hypolimnetic FDOM H was four to five orders-of-magnitude higher than the dark ocean, with much faster turnover rates in dark inland waters versus the dark ocean. Collectively, these findings indicate that the hypolimnion is a hotspot for microbial carbon transformations, and hence an important source and pool of refractory DOM in aquatic systems. The lateral FDOM H flux increased 10.8–32.1% due to hypolimnetic reservoir release during periods of stratification, highlighting the importance of incorporating hypolimnetic carbon transformations into models for carbon cycling of inland waters and the land-sea interface. [Display omitted] [ABSTRACT FROM AUTHOR]

Global land-use changes alter the delivery of fluvial dissolved organic matter (DOM) along land-to-sea continuum. To study how spatial variations in watershed anthropogenic disturbances control chemodiversity and reactivity of DOM exported to oceans, we used fluorescent and ultra-high-resolution mass spectrometry to investigate spatial and seasonal variations of DOM properties along two subtropical coastal rivers with contrasting anthropogenic land-use distributions (North and West tributaries of Jiulong River, southeast China). Dissolved organic carbon (DOC) concentration and humic- and protein-like fluorescent DOM (FDOM) intensities were high in the mixed urban-agricultural impacted upper North River and lower West River. DOM molecular signatures suggested that the urban-sourced DOM is dominated by bio-labile, S-rich compounds, whereas the agricultural-sourced DOM is characterized by a mixture of bio-labile CHONS and bio-refractory CHON. This anthropogenic-induced spatial variation in DOM signatures was especially prominent during the dry season. Molecular analysis indicated that heteroatomic-containing (phosphorus-sulfur-nitrogen) DOM compounds are more biologically degradable, whereas most of the heteroatom-depleted and highly unsaturated CHO was stable during transport. Due to a longer transit distance and reservoir impoundment in North River, the urban-sourced aliphatic compounds were largely microbially removed or transformed into bio-refractory components, resulting in lower DOC fluxes and an increase of recalcitrance in the DOM exported to the ocean. Conversely, shorter transit times for anthropogenic inputs from the middle/lower West River increased watershed yield and export fluxes of DOC with higher bio-lability. Our study documents that transit history plays a crucial role in assessing the fate of anthropogenic DOM along the land-to-ocean continuum., 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 © 2024 Elsevier Ltd. All rights reserved.)

Organic matter removal by cultured Sesuvium portulacastrum in constructed floating beds was studied during a 20 day greenhouse experiment and an 8 month field campaign in the polluted Yundang Lagoon (southeastern China). Experiments were traced via dissolved organic carbon (DOC) concentration, fluorescence excitation-emission matrix and absorption spectroscopy. Two 'terrestrial' humic-like, one 'marine' humic-like and one protein-like components were identified by parallel factor analysis. The 'terrestrial' humic-like and protein-like components, DOC and absorption coefficient (a280) decreased during the greenhouse experiment. The intensities of four fluorescence components were all reduced during the field experiment. These results demonstrate the clear potential of floating bed phytoremediation techniques for reducing organic pollution degree in brackish environments. The rhizosphere may play an important role during phytoremediation. Our results show that spectrophotometric measurements such as fluorescence provide a useful tool for examining the removal of different organic moieties during various bioremediation processes., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Photo-production of dissolved inorganic carbon (DIC) from chromophoric dissolved organic matter (CDOM) is an important transformation process in marine carbon cycle, but little is known about this process in Chinese coastal systems. This study investigated an estuarine water sample and a coastal seawater sample from the subtropical waters in southeast of China. Water samples were exposed to natural sunlight and the absorption and fluorescence of CDOM as well as the DIC concentration were measured in the summer of 2009. The estuarine water had higher CDOM level, molecular weight and proportion of humic-like fluorescent components than the seawater that exhibited abundant tryptophan-like fluorescent component. After a 3-day irradiation, the CDOM level decreased by 45% in the estuarine water and 20% in the seawater, accompanied with a decrease in the molecular weight and aromaticity of DOM which was inferred from an increase in the absorption spectral slope parameter. The photo-degradation rates of all the five fluorescent components were also notable, in particular two humic-like components (C4 and C5) were removed by 78% and 69% in the estuarine water and by 69% and 56% in the seawater. The estuarine water had a higher photo-production rate of DIC than the seawater (4.4 vs. 2.5 micromol/(L x day)), in part due to its higher CDOM abundance. The differences in CDOM compositions between the two types of waters might be responsible for the higher susceptibility of the estuarine water to photo-degradation and hence could also affect the photo-production process of DIC.

During summers in 2007 and 2008, an investigation was conducted to identify the distribution of mosquitoes and circulation of mosquito-borne arboviruses in Inner Mongolia, China. A total of 10,542 mosquitoes consisting of seven species from the Aedes, Culex, and Anopheles genera were trapped by UV-light traps, and they were sorted into 211 pools according to species, location, and date of collection. The result showed that Aedes dorsalis was the most common species, accounting for 41.0% (4327/10,542) of the total. Culex modestus (17.1%, 1801/10,542) made up the second largest species, followed by Aedes flavidorsalis (16.3%, 1714/10,542). Six virus isolates were obtained from pooled mosquitoes using cell culture and were identified as Tahyna virus (two isolates from Ae. dorsalis and C. modestus), Banna virus (one isolate from C. modestus), and Culex Pipiens pallens Densovirus (three isolates from Aedes caspius) by serological and molecular methods.