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Personal care products (PCPs) are widely applied in our daily life, however, little is known about their occurrence in wild fish. We investigated the bioaccumulation and potential risks of 24 PCPs in muscle and liver tissues of wild fish collected from two large rivers of Pearl and Yangtze Rivers in China. The results showed the detection of a total of 13 PCPs including 9 biocides, 2 synthetic musks and 2 benzotriazoles in at least one type of fish tissue from 12 fish species. The compounds with high detection frequencies (> 50%) in fish muscle or liver tissues were N , N -diethyl-3-methylbenzamide, carbendazim, climbazole, miconazole (MCZ), methylparaben, propylparaben, triclosan (TCS), tonalide, galaxolide (HHCB) and 5-methyl-1H-benzotriazole (5-TT). Among biocides, synthetic musks and benzotriazoles, TCS, HHCB and benzotriazole showed the maximum concentrations of 79.5 ng/g wet weight (ww), 299 ng/g ww and 3.14 ng/g ww, respectively, in muscle tissue, while MCZ, HHCB and 5-TT showed the maximum concentrations of 432 ng/g ww, 2619 ng/g ww and 54.5 ng/g ww, respectively, in liver tissue. The median values of logarithm of bioaccumulation factors (BAF) for the detected 13 PCPs were ranged 0.8–3.35 in muscle and 0.85–4.58 in liver. The log BAF values of the PCPs displayed good linear relationships with log K ow and log D ow (pH-dependent K ow ). The health hazard assessment of 10 detected PCPs in the muscle indicated no appreciable risk to human via consumption of the wild fish. [ABSTRACT FROM AUTHOR]

The Yangtze (Changjiang) River enters the East China Sea with huge annual freshwater and sediment deposits. This outflow, known as the Changjiang diluted water ( CDW), causes striking ecological gradients that potentially shape coastal species' distribution and differentiation. The CDW has long been rendered as a marine biogeographic boundary separating cold-temperature and warm-water faunas, but it remains unclear whether and to what extent it acts as an intraspecific barrier. Here, we synthesize published phylogeographic studies related to the CDW to address these issues. We find that the influence of the CDW on population differentiation is taxonomically variable, and even congeneric species may respond differently. In studies that claim the CDW is a phylogeographic barrier, the underlying assumptions explaining observed genetic breaks are sometimes incorrect, and some may have misinterpreted results due to conceptual confusion or insufficient geographic sampling. After excluding these studies, the remaining ones generally show shallow genetic divergence but significant population structure for coastal species across the CDW, suggesting that the CDW has not been a historically persistent barrier, but rather has acted as a filter within some species recently, probably after the last glacial maximum. [ABSTRACT FROM AUTHOR]

Present-day estimations of global nitrogen loss (N-loss) are underestimated. Commonly, N-loss from rivers is thought to be caused by denitrification only in bed-sediments. However, coupled nitrification-denitrification occurring in overlying water with suspended sediments (SPS) where oxic and anoxic/low oxygen zones may coexist is ignored for N-loss in rivers. Here the Yellow and Yangtze Rivers were taken as examples to investigate the effect of SPS, which exists in many rivers of the world, on N loss through coupled nitrification-denitrification with nitrogen stable ( 15 N) isotopic tracer simulation experiments and in-situ investigation. The results showed even when SPS was surrounded by oxic waters, there were redox conditions that transitioned from an oxic surface layer to anoxic layer near the particle center, enabling coupled nitrification-denitrification to occur around SPS. The production rate of 15 N 2 from 15 NH 4 + -N ( R 15N2-production ) increased with increasing SPS concentration ([ SPS ]) as a power function ( R 15N2-production = a ·[ SPS ] b ) for both the SPS-water and bed sediment-SPS-water systems. The power-functional increase of nitrifying and denitrifying bacteria population with [SPS] accounted for the enhanced coupled nitrification-denitrification rate in overlying water. SPS also accelerated denitrification in bed-sediment due to increased NO 3 − concentration caused by SPS-mediated nitrification. For these two rivers, 1 g L − 1 SPS will lead to N-loss enhancement by approximately 25–120%, and the enhancement increased with organic carbon content of SPS. Thus, we conclude that SPS in overlying water is a hot spot for nitrogen loss in river systems and current estimates of in-stream N-loss are underestimated without consideration of SPS; this may partially compensate for the current imbalance of global nitrogen inputs and sinks. [ABSTRACT FROM AUTHOR]

On the basis of monthly runoff series obtained in 1950–2013 and annual sediment load measured in 1956–-2013 at five key hydrological stations in the middle and lower reaches of the Yangtze River basin, this study used the Mann-Kendall methods to identify trend and abrupt changes of runoff and sediment load in relation to human activities. The results were as follows: (1) The annual and flood season runoffs showed significant decreasing trends at Yichang station, and showed slight downward trends at Hankou and Datong stations, while the abrupt changes of dry season runoff at Yichang, Hankou and Datong stations occurred in about 2007 and the change points were followed by significant increasing trends. The construction of the Three Gorges Dam, which began to operate in 2003, influenced the variations of runoff in the mainstream of Yangtze River, but the effect weakened with the distance along the downstream direction from TGD. (2) Since the 1990s, annual sediment loads at Yichang, Hankou, and Datong stations have been decreasing significantly, and after 2002, the annual sediment load at Yichang dropped below that of Hankou and Datong. The dams and deforestation/forestation contributed to the significant decreasing trend of the sediment load. In addition, the Three Gorges Dam aggravated the downward trend and caused the erosion of the riverbed and riverbanks in the middle and lower reaches. (3) The runoff and sediment load flowing from Dongting Lake into the mainstream of the Yangtze River showed significant decreasing trends at Chenglingji station after 1970s, and in contrast, slight increase in the sediment flow from Poyang Lake to the mainstream of the Yangtze River at Hukou station were detected over the post-TGD period (2003–2013). The result of the study will be an important foundation for watershed sustainable development of the Yangtze River under the human activities. [ABSTRACT FROM AUTHOR]

A model has been created for calculating the balanced diversion ratios of flow rate and sediment in the branches of a bifurcated river. The model is based on the extremity law of energy dissipation rate, and involves solving the simultaneous equations of flow and sediment motion for uniform flow in an open channel. The model has been verified by measured data obtained from the Meizizhou and Baguazhou branches of the Yangtze River in China. The parameters that influence the diversion ratios, such as river width, channel roughness and the total inflow, have been analysed. It was found that balanced diversion ratios are more sensitive to river width and roughness than to total inflow. Measures to regulate the Baguazhou branch have been compared further and analysed. The conclusions of this study can provide a theoretical basis for future regulation of the Baguazhou river branch. [ABSTRACT FROM AUTHOR]

Objective: To investigate the prevalence of trematode Aspidogastrea in the freshwater mussels in the Yangtze River basin within Anhui province, China.Methods: We initially harvested the freshwater mussels living in the Yangtze River running through Anhui area, and labeled them with corresponding number. Then the samples were dissected for isolating the flukes, which were identified by conventional staining.Results: Infection rate of trematode Aspidogastrea in freshwater mussels in the Yangtze River basin within the territory of Anhui province was 30.38% (103/339) in general, and a total of 912 flukes of Aspidogastrea were detected in the 103 mussels, with average infection rate of 8.85 for each mussel.Conclusion: Trematode Aspidogastrea is prevalent in the freshwater bivalves living in the Yangtze River basin running through Anhui area, and the treamatode was identified as Aspidogaster sp. belong to Aspidogaste under Aspidogastridae of Aspidogastrea. [ABSTRACT FROM AUTHOR]

Hanjiang river is the longest river in Yangtze river basin, having high economic importance to China for its economically exploitable hydropower and potential water resources. In an attempt to satisfy China's economic and social development needs, the Chinese government has established cascade dams and four relative water diversion projects in Hanjiang river, which aims at transferring water from south (Hanjiang river) to north (water-stricken areas). However, there are increasing eco-environmental concerns associated with the establishment and development of cascade hydropower. In this study, the opportunities and eco-environmental influences related to Hanjiang river's cascade hydropower development are explored and then recommendations are put forward to minimize the potential impacts. The implementation of vigorous projects related to hydropower and water diversion has an important role to play in solving flood, energy and water shortage problems. In addition, the eco-environmental and socio-economic impacts on the middle and downstream and its diversion can be relieved to some degree in the area. However, the establishment of projects can cause several impacts on the local eco-environment. First, Danjiangkou reservoir construction can cause change in water flow, water bloom, soil erosion in the river basin. Second, it can directly lead to the decrease of 10.5 billion cubic meters of water in the middle- and downstream areas, threatening the local supply of drinking water and influencing farming irrigation and industrial production. Finally, the construction of cascade hydropower dams can change the water form and fish stocks may reduce threatening eco-environment security and environmental geology. [ABSTRACT FROM AUTHOR]

The article presents a study which aims to examine the role of ship locks in fish transfer through Three Gorges Dam (TGD) and Genchouba Dam (GD) in China. The study shows that some of the fish have the capacity of entering the locks and might even migrate by the ship locks to Yangtze River upstream part. It reveals that 40 fishes transited the gates of the locks from 04.35 to 22.47, indicating that the peak of fish migration happened during the night in the Yangtze River.

Background: The emergence, resurgence and spread of human food-borne pathogenic Vibrios are one of the major contributors to disease burden and mortality particularly in developing countries with disputable sanitary conditions. Previous research on pathogenic Vibrio cholerae and Vibrio parahaemolitycus derived from clinical samples has proposed links between acquisition of virulence and multiple drug resistance traits and intercellular transmissibility of mobile genetic elements in the environment. To date, very few information is available on environmental Vibrio isolates. In this study, we characterized eleven Vibrio strains bearing the SXT/R391-like integrative and conjugative elements (ICEs) derived from aquatic products and environment in the Yangtze River Estuary, China. Results: The eleven Vibrio strains were isolated in 2010 to 2011, and taxonomically identified, which included six Vibrio cholerae, three Vibrio parahaemolyticus, one Vibrio alginolyticus and one Vibrio natriegens. Most of the strains displayed strong resistance phenotypes to ampicillin, mercury and chromium. The majority of their ICEs, which belong to S and R exclusion system groups, contain ICEs-chromosome junction sequences and highly conserved core-genes required for ICE transfer. However, comparative sequence analysis uncovered interesting diversity in their mosaic accessory gene structures, which carry many novel genes that have not been described in any known ICEs to date. In addition, antibiotic resistance was transmitted by ICEVchChn6 and ICEVpaChn1 from V. cholerae, V. parahaemolyticus to E. coli MG1655 via conjugation, respectively. Our data also revealed that the ICEs characterized in this study are phylogenetically distant from most of the SXT/R391 ICEs reported previously, which may represent a novel cluster likely shaped by the ecological environment in the Yangtze River Estuary, China. Conclusions: This study constitutes the first investigation of ICEs-positive Vibrio spp. in the Yangze River Estuary, China. The newly identified ICEs were characterized with mosaic accessory gene structures and many novel genes. The results demonstrated self-transmissibility of antibiotic resistance mediated by two of the ICEs from V. cholerae, V. parahaemolyticus to E. coli via conjugation, respectively. Our results also revealed that the ICEs examined in this study may represent a novel cluster in the SXT/R391 family. [ABSTRACT FROM AUTHOR]

The measurement of total basin discharge along coastal regions is necessary for understanding the hydrological and oceanographic issues related to the water and energy cycles. However, only the observed streamflow (gauge-based observation) is used to estimate the total fluxes from the river basin to the ocean, neglecting the portion of discharge that infiltrates to underground and directly discharges into the ocean. Hence, the aim of this study is to assess the total discharge of the Yangtze River (Chang Jiang) basin. In this study, we explore the potential response of total discharge to changes in precipitation (from the Tropical Rainfall Measuring Mission-TRMM), evaporation (from four versions of the Global Land Data Assimilation-GLDAS, namely, CLM, Mosaic, Noah and VIC), and water-storage changes (from the Gravity Recovery and Climate Experiment-GRACE) by using the terrestrial water budget method. This method has been validated by comparison with the observed streamflow, and shows an agreement with a root mean square error (RMSE) of 14.30 mm/month for GRACE-based discharge and 20.98 mm/month for that derived from precipitation minus evaporation (P - E). This improvement of approximately 32% indicates that monthly terrestrial water-storage changes, as estimated by GRACE, cannot be considered negligible over Yangtze basin. The results for the proposed method are more accurate than the results previously reported in the literature. [ABSTRACT FROM AUTHOR]

Highlights: [•] We measured REE compositions of the fluvial sediment in Taiwan. [•] The average REE concentrations of fluvial sediment in Taiwan are higher than those of the Changjiang and Huanghe, but lower than the Zhujiang. [•] The REE patterns could be a useful tool for tracing sediment provenances. [•] Sediment provenance and chemical weathering exert important controls over the REE composition. [Copyright &y& Elsevier]

To identify impact factors on the distribution and characters of natural plants community in reclamation area, with survey data from 67 plant quadrats in July 2009, soil properties data from 216 sampling points in April 2009, and TM (30 m) data in 2006, the composition and characteristics of natural plants community in different time of the Fengxian area in the Changjiang (Yangtze) River estuary were analyzed with two-way indicator species analysis (TWINSPAN), multivariate analysis of variance (MANOVA), detrended canonical correspondence analysis (DCCA) and canonical correspondence analysis (CCA). The results show that: 1) The plant communities in the reclaimed area are mainly mesophytes and helophytic-mesophytic transitional communities, showing a gradient distribution trend with the change in reclamation years. Species richness ( MA), species diversity ( H) and above-ground biomass also increase with the increase of reclamation years. Nevertheless, they appear to decline slightly in the middle and late reclamation period (> 30 years). 2) With the rise in land use levels, the changes in species richness and species diversity tend to increase at first and then decrease; species dominance ( D), however, tends to decline; and above-ground biomass increases slightly. 3) The distribution of the plant community is mainly influenced by the following factors: land use levels ( R = 0.55, p < 0.05), soil moisture ( R = 0.53, p < 0.05), soil salinity ( R = 0.43, p < 0.05) and reclamation time ( R = 0.40, p < 0.05). [ABSTRACT FROM AUTHOR]

Abstract: Suzhou is located at the lower reaches of the Yangtze River in southeastern Jiangsu, China. It is part of the Su-Xi-Chang area including Suzhou, Wuxi and Changzhou. As one of the most developed areas in China, this region has suffered from severe land subsidence caused by extensive groundwater exploitation since 1980s. The land subsidence was controlled by prohibition of groundwater exploration in the past several years. However, the surface water pollution prompted a new task of how to sustainably utilize the groundwater resource, especially to satisfy the emergency demands of water supply. In this paper, we took Suzhou as a representative case to discuss how to develop groundwater resources while controlling the land subsidence. The relationship between the deformation and the groundwater level was analyzed, with focus on the deformation features after the period of groundwater exploitation ban. The results confirmed the conclusion by Shi et al. (2007, 2008a): even in the period of rising groundwater level, same units may manifest different deformation characteristics, such as elasticity, elasto-plasticity, and visco-elasto-plasticity, at different locations of the cone of depression. A land subsidence model that couples a 3-D groundwater model and a 1-D deformation model was developed to simulate the groundwater level and deformation. A high-resolution local grid (child model) for Suzhou was built based on the regional land subsidence model of Su-Xi-Chang area by Wu et al. (2009). The model was used for a number of predictive scenarios up to the year of 2012 to examine how to develop sustainable use of groundwater resources under the conditions of land subsidence control. Our results indicated that about 3.08×107 m3/a groundwater could be provided as emergency and standby water source while meeting the land subsidence control target of 10mm/a. [Copyright &y& Elsevier]

This review compares and contrasts the environmental changes that have influenced, or will influence, fishes and fisheries in the Yangtze and Mekong Rivers. These two rivers have been chosen because they differ markedly in the type and intensity of prevailing threats. The Mekong is relatively pristine, whereas the Three Gorges Dam on the Yangtze is the world's largest dam representing the apotheosis of environmental alteration of Asian rivers thus far. Moreover, it is situated at the foot of a planned cascade of at least 12 new dams on the upper Yangtze. Anthropogenic effects of dams and pollution of Yangtze fishes will be exacerbated by plans to divert water northwards along three transfer routes, in part to supplement the flow of the Yellow River. Adaptation to climate change will undoubtedly stimulate more dam construction and flow regulation, potentially causing perfect storm conditions for fishes in the Yangtze. China has already built dams along the upper course of the Mekong, and there are plans for as many as 11 mainstream dams in People's Democratic Republic (Laos) and Cambodia in the lower Mekong Basin. If built, they could have profound consequences for biodiversity, fisheries and human livelihoods, and such concerns have stalled dam construction. Potential effects of dams proposed for other rivers (such as Nujiang-Salween) are also cause for concern. Conservation or restoration measures to sustain some semblance of the rich fish biodiversity of Asian rivers can be identified, but their implementation may prove problematic in a context of increasing Anthropocene alteration of these ecosystems. [ABSTRACT FROM AUTHOR]

Summary: The sediment regime of the Yangtze River (Changjiang) has been altered by intensified human activities over the past decades, particularly dam construction. To investigate the impacts of dam building on the sediment regime in the Yangtze River, two of the largest reservoirs on the upper reach, i.e. the Gezhouba reservoir and the Three Gorges reservoir, have been selected as case study sites. To analyze the changes in sediment regime between pre-dam and post-dam periods, the whole study period was divided into three sub-periods according to the years when these two reservoirs started to store water. On the basis of the time series of daily water discharge and sediment concentration from four key hydrological stations, i.e. Cuntan, Yichang, Hankou and Datong, the alterations of annual, seasonal, monthly and daily sediment regimes in different sub-periods were investigated and the driving forces were explored. The results revealed: the impacts varied with reservoir storage capacity, operation modes and the distance between the target reservoir and the case study site; Sediment trapping in reservoirs together with soil and water conservation measures was of significant impacts on different time scales of sediment regimes. The results of the study could provide references for the assessment of impacts of dam construction on the health and stability of the Yangtze River ecosystem. [ABSTRACT FROM AUTHOR]

Abstract: Global data suggest that erosion rates variously scale with steepness or climate forcing (precipitation or glacial excavation), but the relative influence of these factors has proven difficult to assess without comparisons from a single location. A new suite of detrital 10Be data from the Three Rivers Region, SE Tibet is used to examine the relative importance of rainfall and relief in predicting patterns of erosion rates across a region with a strong gradient in exhumation. The data reveal millennial erosion rates vary by two orders of magnitude, from 0.01 to 8mm/yr across a regional gradient in exhumation rates inferred from previous thermochronology and cosmogenic nuclide data to the west and east of the study region. The new millennial erosion rates mirror the pattern of decreasing exhumation rates from west to east across the region, with the highest rates in the lower Salween River drainage and the lowest rates in the Yangtze River drainage. Erosion rates in the Mekong and Salween River drainages are correlated with mean local relief whereas in the Yangtze River drainage they are correlated most strongly with mean annual rainfall. The tectonic setting of this region, with a strong west to east gradient in exhumation rates which we infer to mirror a gradient in rock uplift, seems to exert a stronger control on erosion rate patterns than rainfall or relief. [Copyright &y& Elsevier]

Abstract: In 2000 and 2003 before the closure of 3-Gorges Dam, numerous sediment samples were taken from the middle-lower Yangtze River channel to examine sediment transport processes and associated hydromorphological nature of the river. Analytical results show that the riverbeds consist mostly of medium to coarse sands and gravelly sands, and fine sand occurs locally, especially near the river coast. The results further indicate a downstream fining trend in riverbed sediment from Yichang to the river mouth, totaling about 1900 km long with 12 sediment zones (I-XII). These were identified as alternate coarse- and fine-grained sediment on the riverbed, although the zonation of I–III below Three-Gorges Dam site is weaker. The mode of sediment transport in the river is dominated by saltation (20–80%), followed by bed-load transport with 3–15%; transport by suspension is quite low. Grain-sizes associated with hydrological parameters have greater values in the Jingjiang Reaches (from Yichang to Chenglingji; unit stream power: 5–18 N m−1s−1, boundary shear stress: 14 Nm−2 and mean flow velocity: 2–3.2 ms−1), whereas the values obtained from Chenglingji downstream are considerably low (<5 N m−1s−1, 1–4 Nm−2 and <0.7–1.5 ms−1). These values, when compared with on-site measured velocity of the ADP flow column, revealed the erosive riverbed sediment transport in the Jingjiang Reaches, and the accumulative riverbed transport downstream, from Wuhan to the river coast. Hydrological parameters together with distribution of grain-sizes indicate a coarsening riverbed in the Jingjiang river, largely because damming peaked since the last half-century. This corroborates the weakening sediment zonation in the Jingjiang Reaches, which is expected to extend further downstream towards the river coast in response to the potential impact of 3-Gorges Dam in the coming decades. [Copyright &y& Elsevier]

Abstract: This paper examines the characteristics of historical floods and associated monsoon precipitation in the Yangtze Catchment, with specific attention given to the middle and lower Yangtze basin. Based on in situ field observations and historical discharge, flood duration, and land-use information, etc, we propose a number of flood characteristics of the basin: 1) floods have occurred more frequently after 1950s, however, changes in discharge can only partially explain the occurrence of the floods; 2) spectral analysis on the annual mean water discharge during 1860–1985 in Hankou hydrological gauging station of the middle Yangtze River reveals 16.4-year and 2.5-year flood recurrences, which become shortened from what has been recorded in the Chinese historical literature on millennial time scale; 3) floods after 1950s tend to have higher water levels (both mean and peak) and longer duration than before, but with remarkably limited inundation area; and 4) a series of flood waves generated by monsoon precipitation in 1998, initiated from the middle Yangtze, highlights the basin-wide climate hazards with a recurrence of around 60 years. Intensifying anthropogenic activity in the last century, including deforestation, dyking, and lake–coast reclamation etc. that results directly in riverbeds aggradation and shrinkage of lake water area in the middle Yangtze basin, are the key causes for recently human-induced floods in the basin. Threatened land property in the basin reminds us to harmonize with the river and provide more space for flooding. [Copyright &y& Elsevier]

Abstract: X-ray diffraction (XRD) mineralogical and grain-size analyses indicate that inner continental shelf sediments in the East China Sea (ECS) represent a unique mixing of clays derived from the Yangtze River and silts/sands from small western Taiwanese rivers. Taiwanese (e.g., Choshui) clays (<2μm) display no smectite but the best illite crystallinity and are only distributed along southeastern Taiwan Strait. Both Yangtze and Taiwanese river clays are illite-dominated, but the poor illite crystallinity and the presence of smectite and kaolinite indicate that Taiwan Strait clays are mainly Yangtze-dominated. In contrast, medium silts (20–35μm) and very fine sands (63–90μm) in the Taiwan Strait are characterized by low feldspar/quartz, low K-feldspar/plagioclase and high kaolinite/quartz, indicating their provenance from Taiwanese rivers. Taiwanese silts and sands are introduced primarily by the way of typhoon-derived floods and transported northward by the Taiwan Warm Current during summer–fall months. Yangtze clays, in contrast, are widely dispersed southward about 1000km to the western Taiwan Strait, transported by the China Coastal Current during winter–spring months. Since most Taiwan Strait samples were collected in May 2006, clay results in this paper might only represent the winter–spring pattern of the dispersal of Yangtze sediments. [Copyright &y& Elsevier]

Abstract: We report analyses of B isotopic compositions in water and suspended particulate matter collected in the Changjiang and its main tributaries. We showed that four sources control the dissolved boron budget; namely atmospheric deposition, evaporite dissolution, anthropogenic inputs and silicate weathering. The contribution of silicate weathering to the dissolved B load ranges from 40% to 50% for the Changjiang main channel and from 45% to 88% for the main tributaries. The isotopic composition of dissolved boron derived from silicate weathering range from −3‰ up to +9‰ suggesting that isotopic fractionation occurs during silicate weathering. The boron isotopic composition of suspended particulate matter range from −11.4‰ to −6‰. Boron derived from silicate weathering is preferentially carried out by the dissolved load which accounts for 30–96% of the total boron. We show that the isotopic compositions of both the dissolved load and suspended particulate matter are controlled by the competition between boron leaching and boron uptake into secondary phases. The first process is characterized by a loss of boron relative to the bedrock without apparent isotopic fractionation whereas the last one is associated to a large isotopic fractionation which enriches the dissolved boron in heavy isotope. [Copyright &y& Elsevier]

The article presents a research on the estimation of glacier runoff and future trends in the Yangtze River source region (YRSR) in China from 1961-2000. Research uses streamflow simulation modelling to quantify the possible effects of the runoff. Study shows that glacier runoff accounts 11.0% of the total river runoff during this period, while its contribution to river runoff increases to 17.0%. It notes that the effect of glacier runoff on river runoff increased in the source region due to the rate of glacier decrease. It was found out that the annual glacier runoff shows a significant increase due to the heightened ice melting in all climate-change scenarios.

Based on the daily observational precipitation data at 147 stations in the Yangtze River Basin during 1960–2005 and projected daily data of 79 grid cells from the ECHAM5/ MPI-OM model in the 20th and 21st century, time series of precipitation extremes which contain AM (Annual Maximum) and MI (Munger Index) are constructed. The distribution feature of precipitation extremes is analyzed based on the two index series. Three principal results were obtained, as stated in the sequel. (i) In the past half century, the intensity of extreme heavy precipitation and drought events was higher in the mid-lower Yangtze than in the upper Yangtze reaches. Although the ECHAM5 model still can’t capture the precipitation extremes over the Yangtze River Basin satisfactorily, spatial pattern of the observed and the simulated precipitation extremes are much similar to each other. (ii) For quantifying the characteristics of extremely high and extremely low precipitation over the Yangtze River Basin, four probability distributions are used, namely: General Extreme Value (GEV), General Pareto (GPA), General Logistic (GLO), and Wakeby (WAK). It was found that WAK can adequately describe the probability distribution of precipitation extremes calculated from both observational and projected data. (iii) Return period of precipitation extremes show spatially different changes under three greenhouse gas emission scenarios. The 50-year heavy precipitation and drought events from simulated data during 1951–2000 will become more frequent, with return period below 25 years, for the most mid-lower Yangtze region in 2001–2050. The changing character of return periods of precipitation extremes should be taken into account for the hydrological design and future water resources management. [ABSTRACT FROM AUTHOR]

Abstract: Three large rivers – the Chang Jiang (Yangtze), Mekong (Lancang Jiang) and Salween (Nu Jiang) – originate in eastern Tibet and run in close parallel over 300km near the eastern Himalayan syntaxis. Seventy-four river water samples were collected mostly during the summer season from 1999 to 2004. Their major element compositions vary widely, with total dissolved solids (TDS) ranging from 31 to 3037mg/l, reflecting the complex geologic makeup of the vast drainage basins. The major ion distribution of the main channel samples primarily reflects the weathering of carbonates. Evaporite dissolution prevails in the headwater samples of the Chang Jiang in the Tibetan Plateau interior, as evidenced by the high TDS (928 and 3037mg/l) and the Na–Cl dominant major element composition. Local tributary samples of the Mekong and Salween, draining the Lincang Batholith and the Tengchong Volcano, show distinctive silicate weathering signatures. We used five reservoirs – rain, halite, sulfate, carbonate, and silicate – in a forward model to calculate the contribution from silicate weathering to the total dissolved load and to estimate the consumption rate of atmospheric CO2 by silicate weathering. Carbonate weathering accounts for about 50% of the total cationic charge (TZ+) in the samples of the Mekong and the Salween exiting the Tibetan Plateau. In the “exit” sample of the Chang Jiang, 45% of TZ+ is from halite dissolution inherited from the extreme headwater tributaries in the interior of the plateau, and carbonates contribute only 26% to the TZ+. The net rate of CO2 consumption by silicate weathering is (103–121)×103 molkm−2 year−1, lower than the rivers draining the Himalayan front. GIS-based analyses indicate that runoff and relief can explain 52% of the spread in the rate of atmospheric CO2 drawdown by silicate weathering, but other climatic (temperature, precipitation, potential evapotranspiration) and geomorphic (elevation, slope) factors also show collinearity. Only qualitative conclusions can be drawn for the significance of lithology due to lack of digitized lithologic information. The effect of the peculiar drainage pattern due to tectonic forcing is not readily apparent in the major element composition or in increased chemical weathering rates. The 87Sr/86Sr ratios and the silicate weathering rates are in general lower in the Three Rivers than in the rivers draining the Himalayan front. [Copyright &y& Elsevier]

Daily precipitation data of 148 measuring stations in the Yangtze River basin (P.R. China) for the period from 1961 to 2002 have been analyzed to detect quasi periodicities in the frequency of occurrence of extreme precipitation events. Extreme precipitation events of duration 1-day and 10-day were defined in terms of 90th percentile threshold exceedances for each station. The time series were standardized, averaged and detrended for each subbasin. Distinct temporal agglomerations of Gaussian peaks in the smoothed time series for all subbasins were detected for certain years. Quasi periodicities features in the time series were analyzed by means of spectrum analyses. Characteristic differences were found for the subbasins with typical significant quasi periodicities in the 2–3 and 3–4 year ranges. Wavelet analyses revealed that the stability of the observed quasi periodicities over time also varied between the subbasins. This results in various degrees of confidence that can be placed on the future extrapolation of Fourier emulations. Our extrapolations suggest occurrences of peaks in the frequencies of extreme precipitation events for most subbasins around the years 2012–2013 and 2017–2018 even though major differences between the subbasins are expected. [ABSTRACT FROM AUTHOR]

The amount of the sediment deposition in the Yichan-Wuhan reach of the middle Yangtze River (also known as Changjiang River) has been determined using the concept of sediment budget at the channel-reach scale. The fill-scour processes of the middle Yangtze River were studied during the period 1956–1997 in response to the variation in sediment load and flow inputs. The results show that 13.3% of the net input of sediment was deposited in the studied river reach. Since 1956, the output sediment load of the studied reach increased with time to 1981, followed by a decline. The increase in output before 1981 can be related to the man-made bend neck-cutoff which caused a decrease in the sediment load diverted through the ‘three outfalls’ (i.e. the three distributaries from the Yangtze main stem to the Dongting Lake) and increased the sediment-carrying capacity of the river. Thereby, the river could transport more sediment to the outlet of the studied river reach. The decrease in the sediment load output after 1984 was directly due to the decreased sediment load at Yichang station. Multiple regression equations have been established to assess the contributions of influencing factors to the variation in sediment deposition amount in the studied river reach. [ABSTRACT FROM AUTHOR]

Yangtze finless porpoises were surveyed by using simultaneous visual and acoustical methods from 6 November to 13 December 2006. Two research vessels towed stereo acoustic data loggers, which were used to store the intensity and sound source direction of the high frequency sonar signals produced by finless porpoises at detection ranges up to 300 m on each side of the vessel. Simple stereo beam forming allowed the separation of distinct biosonar sound source, which enabled us to count the number of vocalizing porpoises. Acoustically, 204 porpoises were detected from one vessel and 199 from the other vessel in the same section of the Yangtze River. Visually, 163 and 162 porpoises were detected from two vessels within 300 m of the vessel track. The calculated detection probability using acoustic method was approximately twice that for visual detection for each vessel. The difference in detection probabilities between the two methods was caused by the large number of single individuals that were missed by visual observers. However, the sizes of large groups were underestimated by using the acoustic methods. Acoustic and visual observations complemented each other in the accurate detection of porpoises. The use of simple, relatively inexpensive acoustic monitoring systems should enhance population surveys of free-ranging, echolocating odontocetes. [ABSTRACT FROM AUTHOR]

In an annual cycle from March 2005 to February 2006, benthic nutrient fluxes were measured monthly in the Dongtan intertidal flat within the Changjiang (Yangtze River) Estuary. Except for NH4 +, there always showed high fluxes from overlying water into sediment for other four nutrients. Sediments in the high and middle marshes, covered with halophyte and consisting of macrofauna, demonstrated more capabilities of assimilating nutrients from overlying water than the low marsh. Sampling seasons and nutrient concentrations in the overlying water could both exert significant effects on these fluxes. Additionally, according to the model provided by previous study, denitrification rates, that utilizing NO3 − transported from overlying water (DW) in Dongtan sediments, were estimated to be from −16 to 193 μmol·h−1·m−2 with an average value of 63 μmol·h−1·m−2 ( n=18). These estimated values are still underestimates of the in-situ rates owing to the lack of consideration of DN, i.e., denitrification supported by the local NO3 − production via nitrification. [ABSTRACT FROM AUTHOR]

Temporal and spatial changes in δ13C and δ15N of particulate organic matter (POM) and Hemiculter leuciseulus were studied in the Yangtze River of China. Isotopic signatures of POM showed seasonal variations, which was assumed to be associated with allochthonous organic input and autochthonous phytoplankton growth. δ13C of H. leucisculus was 1.1% higher than that of POM, which suggested that the food source of H. leucisculus was mostly from the POM. A mass balance model indicated the trophic position of H. leucisculus in the food web of Yangtze River was estimated to be 2.0 - 2.1, indicating that this fish mainly feeds on planktonic organic matter, which agreed with previous gut content analysis. [ABSTRACT FROM AUTHOR]

Nais inflata Liang 1963 is redescribed on the basis of fully mature specimens collected from several localities of the Yangtze River and Yellow River. The observations and redescription resulting from the study of mature specimens supports N. inflata as a valid species. This species is characterized by a thickened body, the ventral crotchets all of the same type with distal tooth usually longer than proximal one, a greater number of dorsal chaetae per bundle, stout dorsal needles with equal minute bifid teeth (<1 µm), presence of penial chaetae, and prostate glands on vasa deferentia instead of atria. The species is most closely related to N. communis Piguet, 1906 and N. variabilis Piguet, 1906. A table comparing allied species is provided. [ABSTRACT FROM AUTHOR]

For the upper and mid-lower Yangtze River basin trends of pan evaporation and reference evapotranspiration are analysed from 1961 to 2000 using daily data of 115 stations. Both pan evaporation and reference evapotranspiration decreased during the summer months contributing most to the total annual reduction. This trend is more significant in the mid-lower than in the upper Yangtze reaches. The decreasing trends can be associated with trends in net radiation and wind speed. Results are compared with the 20th century evaporation simulated by the general circulation model (GCM, ECHAM5/MPI-OM). Also the GCM’s actual evaporation decreases contrasting an overall increase in air temperature. [ABSTRACT FROM AUTHOR]

Interests on climate change in the source region of Yangtze River have been raised since It Is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ18O has been recovered using an Ice core record retrieved in a plat portion of the firn area In the Guoqu Glacier (33°34′37.8″N, 91°10′35.3″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), In November, 2005. By using a significant positive relationship between ice core δ18O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred In the middle of 1970s. Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the beginning of the 21st century. The warming rate recorded in the ice core with 0.5°C/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1°C/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warming and a more sensitive response to global warming in the high elevation region. [ABSTRACT FROM AUTHOR]

After the catastrophic floods along the Yangtze River (Chang Jiang) in 1998, the United Nations Environment Programme and the United Nations Centre for Human Settlements and the State Environmental Protection Administration of China jointly developed a methodology for assessing flood vulnerability that would be user-friendly for policy-makers. This report discusses this methodology, described herein with a trial application to the critical Dongting Lake Region, using an applied analytical hierarchy process to establish vulnerability weights, and geographical information systems to present the results in a readily comprehensible manner. This study is the first vulnerability assessment undertaken in China specifically directed at flood prevention. [ABSTRACT FROM AUTHOR]

The sensitivity of runoff to the climate change in the Longitudinal Range-Gorge Region (LRGR) in southwest China was investigated with a case study in the Longchuan Basin of the upper Yangtze River, where the climate change is more complex due to the influences from both global warming and local topography. Non-updating artificial neural networks were calibrated and validated at the baseline condition and were used to predict the response of runoff under 25 hypothetical climate scenarios, which were generated by adjusting the baseline temperature by -1, 0, 1, 2 and 3°C and by scaling rainfall by 0%, ± 10% and ± 20%. The results indicated that runoff is more sensitive to the increase in rainfall. The annual and seasonal runoff changes were determined by the interaction between temperature and rainfall. At seasonal scale, the direction of change in runoff is more determined by temperature in winter and spring; whereas it is more determined by rainfall in summer and autumn. The LRGR in southwest China may experience a higher frequency of floods in the wet season and more serious droughts in the dry season, if a wetter summer and warmer winter is the trend of future climate change, as predicted by many GCMs. [ABSTRACT FROM AUTHOR]

The occurrences of harmful algal blooms (HABs), in terms of frequency and area in the Chinese coastal waters, have been increasing since 1980s and caused considerable economic losses. In the present study, we have analyzed spatial and seasonal characteristics of HAB events in the southern Yellow Sea and East China Sea along Chinese coast from 1933 to 2004. With a total 435 HAB records, the most frequent HAB occurrence area (FHA) is off the Yangtze River mouth and another two FHA areas are located south of the Yangtze River estuary along about isobaths of 30–60 m coastal water in the East China Sea. The time of HAB occurrence shifted during our study period: from autumn (August–October) before 1980s to July–August in 1980s, during May–July in 1990s, and May–June for the period of 2000–2004. Causative species were found to be different: Noctiluca scintillans and Skeletonema costatum were dominant causative species prior to 2000; and Prorocentrum donghaiense Lu was dominant from 2000 to 2004 and also caused large blooms in May. Trichodesmium sp. caused many HABs in autumn (August–October) prior to 1980s with only one HAB between 1980 and 2004. The changes of the dominant HAB species may have affected the timings of HAB occurrence, as well as the increasing HAB-affected areas in recent years. [ABSTRACT FROM AUTHOR]

According to the study on the aquatic environment of the typical lakes in the middle and lower reaches of Yangtze River, lake eutrophication is a process in which the lake ecosystem degenerates, resulting in the deterioration of the water quality due to the enrichment of the nutrients. Moreover, the succession of lake ecosystem and change of water quality both couple well with the evolvement of trophic state. Then the conceptual model is mentioned and ten lake states are classified. Based on these, the authors analyzed the eutrophication processes of the typical lakes in the middle and lower reaches of Yangtze River. The large lakes with taking in - sending out water typical of Poyang Lake evolve from State 1 before the 1980s into State 2 after the 1980s, the large and medium lakes typical of Taihu Lake evolve from State 1-2 in the 1960s into State 8 in the 1980s then into State 9 in the 1990s, the medium and small shallow lakes typical of Honghu Lake evolve from State 1 in the 1960s into State 2 after the 1980s and the small city (suburban) lakes typical of Donghu Lake evolve from State 2 in the 1960s into State 9 after the 1970s. Further, the 1980s is the key conversion period of the lakes of various types typical of Poyang Lake, Honghu Lake and Taihu Lake converting into mesotrophic state, the 1990s is that of Taihu Lake into eutrophic state and the 1970s is that of the small city (suburban) lakes typical of Donghu Lake into eutrophic state. The series of nutrient evolvement of different typical lakes are similar, but the processes are not synchronous, which is related to the various human and natural driving mechanisms in lake basins. [ABSTRACT FROM AUTHOR]

Sand extraction from the mid-lower Yangtze has increased rapidly since the 1980s, in contrast to a rapid decrease in sediment discharge from the Yangtze River into the sea. In-channel sand extraction poses great risks to flood protection, navigation channels and railway bridges. This paper reviews the recent history of in-channel sand extraction, discussing the present status and potential problems in legislation and management. It is concluded that the share of interests, the involvement of local criminal gangs and official corruption were the main difficulties for the ban on illegal sand extraction. It is proposed that the sites and amounts permitted for in-channel sand extraction should be re-evaluated under the new sediment budget after closure of the Three-Gorges Dam. It is necessary to explore the use of alternative materials in order to reduce the demand for natural sand while meeting the market needs for socio-economic development. [ABSTRACT FROM AUTHOR]

In order to probe anisotropy of magnetic susceptibility (AMS) characteristics of tide-influenced sediments, AMS analyses and primary sedimentary structure observation and description were conducted on the borehole CM-97 samples from Changjiang delta, China. Primary sedimentary structure (cross-laminations) observation and description were based on a detailed examination of X-ray photographs of samples. Primary cross-laminations were found on 19 of 35 subcores, among which five subcores, A6, A7, B17, B30, and B38, have bidirectional cross-laminations. We found a total of 35 cross-laminations on the subcore sections of tide-influenced sediments, of which 14 were distributed on the five subcores with bidirectional cross-laminations. By their bidirectional dipping foreset laminae, the primary cross-laminations clearly showed bidirectional flow features of the environments in which these sediments formed. Comparing the paleocurrent directions shown by these cross-laminations with those indicated by the in situ AMS data, we found that more than 64% exhibited similar current directions, demonstrating that AMS can supply us with the true paleocurrent directions for such sediments. From the downhole paleocurrent changes inferred from the in situ AMS data, it was also clear that there were bidirectional flows during the deposition of these sediments and that sediments deposited in different environments had different change characteristics with respect to downhole paleocurrents. These differences among the muddy intertidal- to subtidal-flat sediments (unit 5), the Changjiang estuary central basin sediments (unit 6), and the delta front sediments (unit 8) may have resulted from the different hydrodynamic conditions of these sedimentary environments. Furthermore, stratigraphic unit 5 was subdivided into three parts based on downhole AMS characteristics, which may correlate with those subdivided according to downhole paleocurrent changes. Therefore, besides its long recognized role in paleocurrent determination, AMS can also be used to determine stratigraphic divisions and to reconstruct sedimentary paleoenvironments in detail. [ABSTRACT FROM AUTHOR]

To evaluate the performance of a computer model simulating runoff and sediment load in the upper region of the Changjiang (Yangtze River) basin over a relatively short time interval, including examining the applicability of the input precipitation data generated from global circulation models and satellite data, we used a spatially distributed model, HSPF with the International Satellite Land Surface Climatology Project (ISLSCP) precipitation data for 1987 and 1988 as input data. The Nash–Sutcliffe coefficient (R2) for 5-day average streamflow was 0.94 in the calibration period and 0.95 in the verification period for the whole upper region. Moreover, the model simulated the 5-day average streamflow well in each main tributary, as shown by R2 values of 0.46–0.96, except that it underestimated the peak flow rates during the flood season over 2 years by up to 71% in Tuojiang and 61% in Jialingjiang. The model simulated the 5-day concentrations of suspended solids (SS) fairly well in the headwaters and upper regions of the Jinshajiang, Yalongjiang, and Minjiang watersheds, as shown by R2 values of 0.31–0.65. In the other regions, however, the model underestimated the SS load by up to 72%, and rarely simulated the fluctuation of SS concentration in each river channel during the flood season. These errors led to the underestimation of sediment runoff volume from the whole upper region during the flood season, as shown by the ratio of the simulated sediment load to the observed data at Yichang: 0.69 in the calibration period and 0.68 in the verification period. The ISLSCP precipitation tended to be more frequent and less intense than the measured precipitation. This was probably the main reason why the HSPF did not perform well in all regions at all times. [ABSTRACT FROM AUTHOR]

This review paper provides a brief review on the development of ideas in the fields of the sea level change of the ECS (East China Sea), the history of the Yangtze River entering the sea and paleochannels in the shelf of the ECS since the Last Glacial Maximum (LGM). The paper summarizes two opposite theories about the Yangtze River entering the sea during the LGM. One theory is that the Yangtze River input a lacustrine in the north of Jiangsu province which was defunct in middle Holocene, and the river was once dry. The other was that the Yangtze River still existed and entered into the Okinawa Trough during the LGM, but scholars share different opinions on which course the river ran across and which place the river input the trough. This paper concludes future work is to study the evolution of the Yangtze River and the paleoclimate and the corresponding events as a whole from the view of regional and even global change, and more attention should be paid to the study on mud sediment, the Yangtze River's response to the changes in climate and sea-level, and the channel metamorphosis. [ABSTRACT FROM AUTHOR]

Reports on information about the Changjiang mouth in August 2000, mentions the satellite image of sea surface temperature (SST) in summer of 1997, and discusses an upwelling event over the submerged river valley (SRV) near the South Passage of the Changjiang estuary and near the center of the Hangzhou Bay mouth. Findings from the three-dimensional numerical model, which indicated the causes of the upwelling; The influence of barotropic effect, baroclinic effect, bottom Ekman effect and their interaction with the slope bottom topography; Conclusion that the dynamic mechanism of this upwelling differs from the one on the continental shelf.

Length-weight relationships were estimated for the first time for five loaches of the Jinshajiang River, China. Four of the species are endemic to China. The scientific names are: Clea dabryi ( Sauvage, 1874); Homatula variegata ( Dabry de Thiersant, 1874); Sinibotia superciliaris ( Gunther, 1892); Triplpphysa anterodorsalis ( Zhu & Cao, 1989); and Triplophysa leptosoma ( Herzenstein, 1888). [ABSTRACT FROM AUTHOR]