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Managing agricultural watersheds in an environmentally friendly manner necessitate the strategic implementation of well-targeted sustainable land management (SLM) practices that limit soil and nonpoint source pollution losses and translocation. Watershed-scale SLM-scenario modeling has the potential to identify efficient and effective management strategies from the field to the integrated landscape level. In a case study targeting a 66-hectare watershed in Petzenkirchen, Lower Austria, the Soil and Water Assessment Tool (SWAT) was utilized to evaluate a variety of locally adoptable SLM practices. SWAT was calibrated and validated (monthly) at the catchment outlet for flow, sediment, nitrate-nitrogen (NO3–N), ammonium nitrogen (NH4–N), and mineralized phosphorus (PO4–P) using SWATplusR. Considering the locally existing agricultural practices and socioeconomic and environmental factors of the research area, four conservation practices were evaluated: baseline scenario, contour farming (CF), winter cover crops (CC), and a combination of no-till and cover crops (NT + CC). The NT + CC SLM practice was found to be the most effective soil conservation practice in reducing soil loss by around 80%, whereas CF obtained the best results for decreasing the nutrient loads of NO3–N and PO4–P by 11% and 35%, respectively. The findings of this study imply that the setup SWAT model can serve the context-specific performance assessment and eventual promotion of SLM interventions that mitigate on-site land degradation and the consequential off-site environmental pollution resulting from agricultural nonpoint sources. [ABSTRACT FROM AUTHOR]

Extreme precipitation poses a severe threat to the natural ecosystem, socioeconomic development, and human life. Investigating the spatiotemporal variations in extreme precipitation and exploring the potential drivers have implications for disaster risk reduction and water resource management. In this study, we analyzed the changes in nine extreme precipitation indices (EPIs) over the Wei River Basin (WRB) during 1957–2019. Furthermore, we assessed the effect of geographic factors (latitude, longitude, and altitude) on the spatial distribution of EPIs and the potential impact of ocean–atmosphere circulation on the temporal variability of EPIs. The results indicate that six EPIs present a downward trend and three EPIs show an upward trend, but all the trends are not significant. In the seasonal scale, max 1-day precipitation amount (RX1day) increases significantly in summer (P < 0.05), while the trends in max 5-day precipitation amount (RX5day) are not significant in all seasons. The period of about 8 years and less than 3 years were observed in most EPIs. The mean values of EPIs except consecutive dry days (CDD) gradually increase from northwest to southeast of the WRB. Latitude, longitude, and altitude are important factors affecting the spatial distribution of the extreme precipitation. Southern Oscillation Index (SOI) and Atlantic Multidecadal Oscillation (AMO) contribute the most to EPIs variation. Interdecadal and interannual oscillations occur between most EPIs and ocean-atmospheric circulation factors, but their phase relationships are different. Our findings highlight the importance of examining global and local driving factors of trend in regional extreme precipitation by a systematic approach, and help to further understand the precipitation changes in the WRB. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs) are vital antigen-presenting cells (APCs) in the immune system, whose apoptosis is closely related to the development of sepsis. Mitophagy is one of the necessary forms of selective autophagy that removes damaged or dysfunctional mitochondria to regulate immunity and inflammation. However, its effect on the apoptosis of DC in sepsis remains unknown. Here, we showed that sepsis activated the apoptosis and mitophagy of DC, and mitophagy had an anti-apoptotic effect on sepsis-induced DC apoptosis. In this study, we used cecal ligation and puncture (CLP) to simulate the pathophysiological state of sepsis. Apoptosis and mitophagy of DC were significantly enhanced in CLP mice compared with controls, and in the Pink1-KO (Pink1-knockout) mice CLP model, the level of apoptosis in DC was further increased while the level of mitophagy was decreased. In addition, more severe mitochondrial dysfunction was exhibited in DC of Pink1-KO mice CLP model compared to wild-type (WT) mice. The results suggest that Pink1/Parkin-mediated mitophagy is activated during sepsis and has an anti-apoptotic effect on DC, which regulates immune functions. [ABSTRACT FROM AUTHOR]

Extreme precipitation events bring considerable risks to the natural ecosystem and human life. Investigating the spatial-temporal characteristics of extreme precipitation and predicting it quantitatively are critical for the flood prevention and water resources planning and management. In this study, daily precipitation data (1957–2019) were collected from 24 meteorological stations in the Weihe River Basin (WRB), Northwest China and its surrounding areas. We first analyzed the spatial-temporal change of precipitation extremes in the WRB based on space- time cube (STC), and then predicted precipitation extremes using long short-term memory (LSTM) network, auto-regressive integrated moving average (ARIMA), and hybrid ensemble empirical mode decomposition (EEMD)-LSTM-ARIMA models. The precipitation extremes increased as the spatial variation from northwest to southeast of the WRB. There were two clusters for each extreme precipitation index, which were distributed in the northwestern and southeastern or northern and southern of the WRB. The precipitation extremes in the WRB present a strong clustering pattern. Spatially, the pattern of only high-high cluster and only low-low cluster were primarily located in lower reaches and upper reaches of the WRB, respectively. Hot spots (25.00%–50.00%) were more than cold spots (4.17%–25.00%) in the WRB. Cold spots were mainly concentrated in the northwestern part, while hot spots were mostly located in the eastern and southern parts. For different extreme precipitation indices, the performances of the different models were different. The accuracy ranking was EEMD-LSTM-ARIMA > LSTM > ARIMA in predicting simple daily intensity index (SDII) and consecutive wet days (CWD), while the accuracy ranking was LSTM > EEMD-LSTM-ARIMA > ARIMA in predicting very wet days (R95P). The hybrid EEMD-LSTM-ARIMA model proposed was generally superior to single models in the prediction of precipitation extremes. [ABSTRACT FROM AUTHOR]

Whether the evaporation paradox exists or not is crucial for an improvement of water resource management on the Chinese Loess Plateau that has long been suffering from water scarcity. An in-depth understanding on long-term changes in evaporation and its attribution would be beneficial for a clear identification of evaporation paradox. However, the long-term and large-scale studies on evaporation variations were severely lacking on the Loess Plateau. This study examined both spatial and temporal variations in pan evaporation at 52 meteorological stations widespread on the Loess Plateau during 1961–2015. The Mann–Kendall test showed that significant decreases occurred in annual and seasonal pan evaporation (p < 0.05). A principal component analysis indicated that regional-averaged annual pan evaporation experienced a decreasing trend in all three regions (the southwestern, southeastern and the northern regions of the Loess Plateau) with a decreasing rate ranging from −1.83 to −5.18 mm/a (p < 0.05). The annual pan evaporation averaged across all the observations decreased significantly, whereas the average annual temperature increased, indicating the occurrence of a pan evaporation paradox on the Loess Plateau. Our results also showed that the pan evaporation was mostly sensitive to actual vapor pressure (ea), followed by solar radiation (Rs), mean temperature (Tmean) and wind speed (U2). An increase in temperature resulted in an elevated pan evaporation; however, this was offset by an increase in vapor pressure and a decrease in wind speed and solar radiation. Wind speed was the dominant factor contributing to the pan evaporation decrease on the Loess Plateau. The results provided a useful reference for a more effective regional water resource management and ecological restoration. [ABSTRACT FROM AUTHOR]

Runoff and sediment discharge have displayed great reductions due to climate change and enhanced various human activities during recent decades in the Jialing River, China, with significant environmental and social implications. The water balance equation, double mass curve, and linear regression analysis were employed to quantify the contributions of climate change and human activities to runoff and sediment discharge reductions in the Jialing River during 1960–2017. The results indicated that the annual runoff of the Jialing River exhibited a significant decreasing trend of − 2.75 × 108 m3 every year (P < 0.05) but no significant abrupt change occurred, while annual sediment discharge significantly decreased by 0.03 × 108 t every year (P < 0.05) with a significant abrupt change in 1990 (P < 0.05). Climate change led to a great reduction (82.2%) in annual runoff from 1960 to 2017 in the Jialing River, whereas the contribution of climate change to sediment discharge reduction in the human-affected period (1990–2017) was only 4.55% and precipitation inclined to increase sediment discharge in recent years (2010–2017). The reduced sediment discharge in the 1990s was mostly due to the implementation of soil–water conservation programs and the reduction after 2000 was due to the development of reservoirs as well as the implementation of soil–water conservation programs. The results provided references to develop various human activities better and drew great attention to strengthening basin management. [ABSTRACT FROM AUTHOR]

In recent decades, the ecohydrology discipline was developed to provide theoretical and technical foundations for the protection and restoration of complex ecological systems (e.g., mountains, rivers, forests, farmlands, and lakes), and to further ecological civilization construction and green development in China. In this study, the progress and challenges of the ecohydrology discipline are elaborated, and the future development directions are proposed according to international scientific frontiers and national ecological civilization construction demands. Overall, the main discipline directions are to develop new ecohydrological monitoring methods, to comprehensively understand ecohydrological mechanisms and their basic theories, to promote integration of multi-scale and multi-variable models by considering both terrestrial and aquatic ecosystems, and to encourage multidisciplinary integration, particularly with the social sciences. Furthermore, the future research interests in China include: combining multi-source information, constructing comprehensive monitoring systems, studying spatiotemporal patterns of key ecohydrological variables and their variation characteristics, developing integrated models of ecological, hydrological, and economic processes, estimating their uncertainty; and conducting interdisciplinary studies that include the natural and social sciences. The application prospects in China are further explored for a variety of ecosystems, including forests, grasslands, rivers, lakes, wetlands, farmlands, and cities. This study will provide a reference to support the development of the ecohydrology discipline in China, and will provide a solid theoretical and technical foundation for the implementation of national ecological civilization construction. [ABSTRACT FROM AUTHOR]

Aims: Since the 1970s, extensive croplands were converted to forest and pasture lands to control severe soil erosion on the Loess Plateau of China. We quantify the direct and indirect effects of vegetation restoration on runoff and sediment yield on hillslopes in the field to improve environmental governance. Methods: An artificial rainfall experiment at a rainfall intensity of 120 mm h−1 and a slope gradient of 22° were used to distinguish the effects of vegetation restoration on runoff and sediment yield. Results: Compared to the farmland slopes, vegetation restoration directly prolonged the time-to-runoff by 140%, reduced the runoff rate by 20%, and increased the soil infiltration capacity by 15%. Vegetation restoration indirectly delayed the time-to-runoff by 120%, reduced the runoff rate and sediment yield rate by 50% and 94%, respectively, and increased the soil infiltration capacity by 58% on the hillslopes with vegetation restoration. Conclusions: The direct effects of vegetation restoration on runoff and sediment yield were lower than its indirect impacts. Vegetation cover, decreases in soil bulk density, and increases in belowground root biomasses and > 0.25 mm aggregate stability were the primary causes of runoff and sediment yield reduction on the slopes with vegetation restoration. [ABSTRACT FROM AUTHOR]

Purpose: Significant changes in the runoff and sediment load have been detected in many catchments of the Loess Plateau. These changes are expected to be influenced by the interplay of climate variability and human activities. Quantitatively evaluating these effects is crucial for framing climate variability adaptation measures and the assessment and management of regional water resources. Materials and methods: Based on the annual rainfall, runoff, and sediment load data taken over the period from 1974 to 2013 and using data from 112 flood events, this study investigates the runoff and sediment load variations at the annual scale and distinguishes the impacts of climate variability and human activities at the event scale. The Mann-Kendall test and Pettitt's test are employed to detect the trends and abrupt change points of the annual runoff and sediment load. Rainfall and land surface conditions play a dominant role in the runoff and sediment yield of flood events. However, vegetation recovery, which benefits from the Grain-for-Green project and the construction of check dams has greatly changed the land surface condition, resulting in a reduction in streamflow energy, hydrological connectivity, and flood peaks. Therefore, for two flood events with similar rainfall conditions but different runoff and sediment yield, the differences in the runoff and sediment load within paired events may be attributed to the changes in the land surface condition induced by human activities. Results and discussion: The results showed that the annual runoff and sediment load has significantly decreasing trends (p < 0.05). The abrupt changing point was detected in 1996, dividing the runoff and sediment load series into a baseline period (1974–1995) and a changing period (1996–2013). At the flood event scale, the hysteresis analysis showed that the counter-clockwise and figure-eight loops are the main patterns for both of the periods. The relationships between the runoff depth (H) and sediment yield (SY) varied greatly in 2007–2013 compared with those during 1974–1989. Human activities accounted for an average of 47 and 81% for the changes in the runoff and sediment load, respectively, and the remainder was attributable to climate variability. Conclusions: Human activities have a greater effect on the sediment load reduction in the Xichuan River catchment, while climate variability accounted for more of the runoff changes. [ABSTRACT FROM AUTHOR]

Accelerated soil erosion exerts adverse effects on water and soil resources. Rainfall erosivity reflects soil erosion potential driven by rainfall, which is essential for soil erosive risk assessment. This study investigated the spatiotemporal variation of rainfall erosivity and its impacts on sediment load over the largest freshwater lake basin of China (the Poyang Lake Basin, abbreviate to PYLB). The spatiotemporal variations of rainfall erosivity from 1961 to 2014 based on 57 meteorological stations were detected using the Mann–Kendall test, linear regression, and kriging interpolation method. The sequential t test analysis of regime shift (STARS) was employed to identify the abrupt changes of sediment load, and the modified double mass curve was used to assess the impacts of rainfall erosivity variability on sediment load. It was found that there was significant increase (P < 0.05) in rainfall erosivity in winter due to the significant increase in January over the last 54 years, whereas no trend in year and other seasons. Annual sediment load into the Poyang Lake (PYL) decreased significantly (P < 0.01) between 1961 and 2014, and the change-points were identified in both 1985 and 2003. It was found that take annual rainfall erosivity as the explanatory variables of the double mass curves is more reasonable than annual rainfall and erosive rainfall. The estimation via the modified double mass curve demonstrated that compared with the period before change-point (1961–1984), the changes of rainfall erosivity increased 8.0 and 2.1% of sediment load during 1985–2002 and 2003–2014, respectively. Human activities decreased 50.2 and 69.7% of sediment load during the last two periods, which indicated effects of human activities on sediment load change was much larger than that of rainfall erosivity variability in the PYLB. [ABSTRACT FROM AUTHOR]

Purpose: Extensive vegetation recovery has been implemented to control severe soil erosion on the Loess Plateau, China. However, no systematic study has been done on the soil improvement benefit and preferable pattern of vegetation rehabilitation. In this study, the effects of vegetation restoration on soil physical properties at ten sites with different vegetation types and varying restoration periods were investigated.Materials and methods: The experiment was carried out in the Yanhe river basin in the hilly-gully region of the Loess Plateau. Ten sites, including two replanted arboreal forests for 25 and 35 years, three replanted scrubland for 15, 30, and 45 years, four secondary natural grassland for 10, 20, 30, and 40 years, and one farmland, were selected for soil sampling. Sampling was conducted at 0-20 cm and 20-40 cm layers.Results and discussion: Vegetation restoration significantly decreased bulk density, and increased aggregate stability and saturated hydraulic conductivity (Ks), while their effects on porosity was complicated. The soil texture class did not change with vegetation succession, but minor differences in sand, silt, and clay components were observed. Bulk density, macroporosity, and > 0.25 mm aggregate stability were the principal physical parameters that affected Ks. Moreover, bulk density had the most effect on Ks (− 0.84), while > 0.25 mm aggregate stability had the lowest impact (0.38). Bulk density and Ks were correlated with most of the other soil physical properties. Replanted scrubland and secondary natural grassland had higher soil physical quality index (SDexter) than replanted arboreal forests and farmland.Conclusions: It is reasonable to take bulk density and Ks as the indicators to evaluate the effect of vegetation restoration on soil physical properties. Planting shrubs and grassland is better than forest for eco-environment rehabilitation in the study area. Results of this study provide a reference to regional eco-environmental rehabilitation and conservation. [ABSTRACT FROM AUTHOR]

Assessing regional patterns and trends in extreme precipitation is crucial for facilitating flood control and drought adaptation because extreme climate events have more damaging impacts on society and ecosystems than simple shifts in the mean values. In this study, we employed daily precipitation data from 231 climate stations spanning 1961 to 2014 to explore the changes in precipitation extremes on the Loess Plateau, China. Nine of the 12 extreme precipitation indices suggested decreasing trends, and only the annual total wet-day precipitation (PRCPTOT) and R10 declined significantly: − 0.69 mm/a and − 0.023 days/a at the 95% confidence level. The spatial patterns in all of the extreme precipitation indices indicated mixed trends on the Loess Plateau, with decreasing trends in the precipitation extremes at the majority of the stations examined in the Fen-Wei River valley and high-plain plateau. Most of extreme precipitation indices suggested apparent regional differences, whereas R25 and R20 had spatially similar patterns on the Loess Plateau, with many stations revealing no trends. In addition, we found a potential decreasing trend in rainfall amounts and rainy days and increasing trends in rainfall intensities and storm frequencies in some regions due to increasing precipitation events in recent years. The relationships between extreme rainfall events and atmospheric circulation indices suggest that the weakening trend in the East Asia summer monsoon has limited the northward extension of the rainfall belt to northern China, thereby leading to a decrease in rainfall on the Loess Plateau. [ABSTRACT FROM AUTHOR]

Check dam has become an efficient measure to control sediment transport and soil erosion in the gully areas. It plays an important role in soil erosion control and agricultural production in the Loess Plateau. Due to construction of numerous check dams, it is necessary to assess the impact of check dams on runoff and sediment load at basin scale. This study applied the SWAT model to simulate monthly runoff and sediment load in the Huangfuchuan basin in the middle reaches of the Yellow River. Twenty key check dams are coupled to the SWAT model simulation in the calibration (1978-1984) and validation period (1985-1989). The determination coefficient ( R ) and the Nash-Sutcliffe coefficient ( NS) were 0.94 and 0.83 for runoff, and 0.82 and 0.81 for sediment load in the calibration period, respectively. During the validation period, the R and NS were 0.93 and 0.80 for runoff, and 0.90 and 0.83 for sediment load respectively. The results showed that the model simulation was acceptable. Subsequently, the calibrated model was used to examine the effect of check dams on runoff and sediment load between 1990 and 2012. It showed that the increasing check dams contributed 24.8 and 27.7% to the decrease of annual runoff and sediment load during the period of 1990-1999, whereas it reached up to 65.2% for runoff decline and 78.3% for sediment load reduction within 2000-2012. Overall, this study illustrated a case study of the dominant role of check dams on variation of runoff and sediment load in the Huangfuchuan basin. [ABSTRACT FROM AUTHOR]

Highly concentrated precipitation, where a large percentage of annual precipitation occurs over a few days, may include a high risk of flooding and severe soil erosion. Thus, areas with severe erosion such as the Loess Plateau in China are particularly vulnerable to highly concentrated precipitation events due to climate change. In this study, we investigated spatial and temporal patterns in the concentration of rainfall in the Middle Yellow River (MYR) from the last 56 years (1958-2013). We used daily and monthly precipitation data from 26 meteorological stations in the study area to calculate the precipitation concentration index (PCI) and the concentration index (CI). The southern and northern parts of the MYR were characterized by a lower CI with a decreasing trend, while the middle parts had a higher CI with an increasing trend. High PCI values occurred in the southern MYR, while lower PCIs with a more homogenous rainfall distribution were found mainly in the northern parts of the MYR. The annual PCI and CI exhibited positive trends at most stations, although only a minority of stations had significant trends ( P < 0.05). At seasonal scales, CI exhibited significantly increasing trends in winter at most stations, while a few stations had significant trends in the other three seasons. These findings provide important reference information to facilitate ecological restoration and farming operations in the study region. [ABSTRACT FROM AUTHOR]

We analyze the variability of sediment discharge and runoff in the Hekou-Longmen segment in the middle reaches of the Yellow River, China. Our analysis is based on Normalized Difference Vegetation Index (NDVI), sediment discharge, runoff, and monthly meteorological data (1961-2010). The climate conditions are controlled via monthly regional average precipitation and potential evapotranspiration (ET) that are calculated with the Penman-Monteith method. Data regarding water and soil conservation infrastructure and their effects were investigated as causal factors of runoff and sediment discharge changes. The results indicated the following conclusions: (1) The sediment concentration, sediment discharge, and annual runoff, varied considerably during the study period and all of these factors exhibited larger coefficients of variation than ET and precipitation. (2) Sediment discharge, annual runoff, and sediment concentration significantly declined over the study period in a linear fashion. This was accompanied by an increase in ET and decline in precipitation that were not significant. (3) Within paired years with similar precipitation and potential evapotranspiration conditions (SPEC), all pairs showed a decline in runoff, sediment discharge, and sediment concentration. (4) Human impacts in this region were markedly high as indicated by NDVI, and soil and water measurements, and especially the soil and water conservation infrastructure resulting in an approximately 312 Mt year of sediment deposition during 1960-1999. [ABSTRACT FROM AUTHOR]

Water shortages have become one of the most severe problems in semi-arid regions throughout the world. Although semi-arid regions have always been dry, human activities and climate change are acerbating the problem. In Chinese Yellow River basin, the river is the major source of freshwater for those living there, and they have long suffered from serious water shortages. However, increasing population and decreasing streamflow are making these shortages more acute. This study seeks to quantify changes in available water in the Yellow River basin over the last 100 years and attempts to determine causes for these changes. To do this, the study evaluated changing trends and regime shifts of streamflow using long term historical records at different hydrological stations in the Yellow River basin over the past century. The results show that annual streamflow has a significant decreasing trends (P < 0.01) in the mid-lower reaches of the basin. Streamflow decomposition by the breaks for additive seasonal and trend approach suggest that this trend can be decomposed into four distinct annual stages (1919-1933, 1934-1969, 1970-1986 and 1987-2011), while the seasonal component demonstrated an evident regime shift in 1986. This regime shift is mainly related to the construction of large reservoirs in the basin. The flow duration curves illustrate a decrease in the magnitude of streamflow over the last century with a relatively uniform flow regime at all stations. The reconstructed streamflow at Toudaoguai station suggests that agricultural irrigation is predominantly responsible for streamflow reductions between Lanzhou and Toudaoguai stations with approximately 9.1 km/a of water extracted between 1997 and 2006. Meanwhile, a decrease of incoming water from upper reaches and soil and water conservation measures were responsible for the significant decline in annual streamflow at mid-lower reaches station. The result of this paper should be of use for water resources planning, watershed management and climate adaptation as they demonstrate how natural and anthropogenic drivers influence water availability in semi-arid regions. [ABSTRACT FROM AUTHOR]

The carbon and water cycles of terrestrial ecosystems, which are strongly coupled via water use efficiency (WUE), are influenced by global climate change. To explore the relationship between the carbon and water cycles and predict the effect of climate change on terrestrial ecosystems, it is necessary to study the WUE in global terrestrial ecosystems. In this study, the 13-year WUE (i.e., net primary production (NPP)/evapotranspiration (ET)) of global terrestrial ecosystems was calculated based on the Moderate Resolution Imaging Spectro-radiometer (MODIS) NPP (MOD17A3) and ET (MOD16A3) products from 2000 to 2012. The results indicate that the annual average WUE decreased but not significantly, and the 13-year mean value was 868.88 mg C m mm . The variation trend of WUE value for each pixel differed greatly across the terrestrial ecosystems. A significant variation ( P<0.05) occurred in about 18.50% of the land surface. WUE was spatially distributed from 0 to 2541 mg C m mm , and 58.78% of the WUE values were concentrated in the interval of 600-1200 mg C m mm . The WUE increased from north to south in Africa and Oceania and from east to west in Europe and South America. Both latitudinal and longitudinal gradients existed in Asia and North America. The following trends in the WUE of different continents and Köppen-Geiger climates were observed: Europe (1129.71 mg C m mm )> Oceania (1084.46 mg C m mm )> Africa (893.51 mg C m mm )> South America (893.07 mg C m mm )> North America (870.79 mg C m mm )> Asia (738.98 mg C m mm ) and warm temperate climates (1094 mg C m mm )> snowy climates (862 mg C m mm )> arid climates (785 mg C m mm )> equatorial climates (732 mg C m mm )> polar climates (435 mg C m mm ). Based on the WUE value and the present or future rainfall, the maximum carbon that fixed in one region may be theoretically calculated. Also, under the background of global climatic change, WUE may be regarded as an important reference for allotting CO emissions offsets and carbon transactions. [ABSTRACT FROM AUTHOR]

Taihu Basin is one of the most developed and industrialized regions in China. In the last two decades, rapid development of economy as well as an increase in population has resulted in an increase of pollutants produced and discharged into rivers and lakes. Much more attention has been paid on the serious water pollution problems due to high frequency of algal blooming. The dataset, obtained during the period 2001-2002 from the Water Resources Protection Bureau of the Taihu Basin, consisted of eight physicochemical variables surveyed monthly at 22 sampling sites in the Taihu Basin, China. Principal component analysis (PCA) and cluster analysis (CA) were used to identify the characteristics of the surface water quality in the studied area. The temporal and spatial variations of water quality were also evaluated by using the fuzzy synthetic evaluation (FSE) method. PCA extracted the first two principal components (PCs), explaining 86.18% of the total variance of the raw data. Especially, PC1 (73.72%) had strong positive correlation with DO, and was negatively associated with COD, COD, BOD, NH-N, TP and TN. PC2 (12.46%) was characterized by pH. CA showed that most sites were highly polluted by industrial and domestic wastewater which contributed significantly to PC1. The sites located in the west of Lake Taihu were influenced by farmland runoff which may contribute to nitrogen pollution of Lake Taihu, whereas the monitoring sites in the eastern of Lake Taihu demonstrated that urban residential subsistence and domestic wastewater are the major contaminants. FSE indicates that there is no obvious variance between 2001 and 2002 among most sites. Only several sites free from point-source pollution appear to exhibit good water quality through the studied period. [ABSTRACT FROM AUTHOR]

Quantitative assessment of sediment yield and sources is of great importance for future soil and water conservation and watershed management in erosion-prone areas. This study investigated sediment yield and sources by using a simple fingerprinting method in a dam-controlled watershed on the northern Loess Plateau. The sampling sediment profile exhibited 24 flood couplets corresponding to rainfall storms from 2001 to 2014. A total of 2.05 × 105 t sediment was trapped during the period. The annual sediment yield varied from 0 to 430 t ha−1 year−1, with an average annual sediment yield of 146.1 t ha−1 year−1. Ten sediment properties (i.e., σ13C, σ15N, TOC, TN, C/N, Xlf, Xhf, Xfd, 137Cs, 210Pb) were potentially selected to identify the sediment sources. The multivariate discriminant function analysis (DFA) test suggested that three soil properties (Χhf, TN, and 137Cs) comprised the optimum composite fingerprinting. The results demonstrated that sandstone contributed nearly 90% of sediment in 2012 and 56.1% in 2003. The contribution from arable land varied from 5.2% in 2005 to 44.6% within the period of 2013–2014. On average, approximately 74.06% of sediment originated from the weathered sandstone, followed by 15.67% from arable land, and the remaining 10.27% from uncultivated land. Our finding indicated that bare sandstone was the main sediment source, leading to relatively high sediment yield in the study area. This study provides a method with great potential for sediment yields assessment and sediment source identification in ungauged watersheds on the Loess Plateau. [ABSTRACT FROM AUTHOR]

A correction to the article "Spatial-temporal characteristics of surface water quality in the Taihu Basin, China" is presented.