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This paper discusses projections of heavy rainfall events in China during the 21st century based on daily precipitation data from the Fourth Assessment Report's (AR4) Coupled General Circulation Models (CGCM). Results show that all three experimental scenarios (scenarios A2, A1B, and B1) project consistent changes in frequency and intensity of heavy rainfall at the end of 21st century. In the regions of Northeast China and North China, there are no significant changes in frequency but there are remarkable increases in intensity of heavy rainfall, indicating that enhanced intensity is the main contributor to increased ratios of heavy rainfall to total annual precipitation in these regions. In regions of the lower reaches of Yangtze River and South China, increases in the amount of heavy rainfall are closely associated with increased frequency and increased intensity. Projected frequencies of heavy rainfall at the end of 21st century increase by 30.9 ∼ 56.6% in the Yangtze River and 35.9 ∼ 50.2% in South China compared to the period of 1980-1999, and projected intensities increase by 1.0 ∼ 5.7% and 2.8 ∼ 6.3%, respectively. Additionally, the ratios of heavy rainfall to total annual precipitation increase by 2.3 ∼ 5.4% in the Yangtze River and 1.8 ∼ 3.8% in South China. The significant increases of heavy rainfall ratios indicate that as the climate warms, heavy rainfall events are expected to increase at rates that are much faster than increases in total precipitation amounts, indicating that China will experience increased amounts of flooding. These results are substantially consistent among the three IPCC (Intergovernmental Panel on Climate Change) scenarios. The increased probability of heavy rainfall events in China is closely connected with increased transportation of water vapour from the Arabian Sea and the South China Sea. Additionally, atmosphere stratification has become increasingly unstable, which has provided a favorable background for the initiation of heavy rainfall at the end of the 21st century. Copyright © 2010 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

Solar radiation (Rs), a critical variable in agricultural and eco-environmental processes, is not measured at many meteorological stations. Prediction of Rs has drawn increasing attention in the recent years. However, due to the dynamic nature of atmosphere, accurate estimation of Rs from routinely measured meteorological variables is a challenging task. Studies have demonstrated that machine-learning approaches outperformed traditional statistical methods. This paper presents an application of Support Vector Machines (SVMs) for monthly mean daily Rs estimates using measured maximum, minimum, and mean air temperatures (Tmax, Tmin, and Tmean, respectively). Twenty-four stations covering different climatic regions-cold (C), severe cold (SC), mild (M), hot summer and cold winter within the Yangtze River Plain (HSCW-A), and hot summer and cold winter within the Sichuan Basin (HSCW-B)-across China were gathered and analysed. Five SVM models with different input attributes were created. These models were also compared with two empirical temperature-based methods. Root mean squared error (RMSE), Nash-Sutcliffe coefficient (NSE), and coefficient of residual mass (CRM) were employed to compare the performances of different methods. The newly developed model, SVM using Tmax-Tmin, and Tmean, outperformed other models with an averaged RMSE of 1.637 MJ m−2 and NSE of 0.813. On a regional scale, when Rs was estimated using the parameters developed at other sites, estimation of Rs within HSCW-B and SC regions were more reliable than in other zones. Especially in HSCW-B region, estimates of Rs using the parameters developed at Zunyi gave better performance (RMSE = 1.117 MJ m−2, NSE = 0.922) than that using the parameters obtained from their own data (RMSE = 1.309 MJ m−2, NSE = 0.894). The results showed that the SVM methodology may be a promising alternative to the traditional approach for predicting solar radiation at any locations where the records of air temperatures are available. Copyright © 2010 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

This paper examines the morphological development of the Yangtze River mouth, which has been diverting southeasterly (dextrally), according to historical (150 years) chart-based digital evolution model and on-site measured tidal flow data. We reveal a significantly narrowing of the northern river mouth branch from formerly >30 km wide to presently 10 km wide due to rapid siltation. Net siltation there, however, decreases gradually, which largely contrasts with the fact that the siltation has shifted to the southern river mouth area, as shown by many newly-emerged estuarine islands, sandy shoals and bifurcated branches. Our data have further demonstrated that the ebb flow that dominates in the study area changes its direction gradually from east to southeast from the inner to outer river mouth area, and its duration is much longer than the flood flow in the inner river mouth area, but nearly equal at the river mouth area. Accordingly, the sediment transport pathway has been diverted from east to southeast. We examine whether the Coriolis Force could explain the dextral diversion of the ebb flow and the altered morphodynamical processes. Although too weak to strengthen the tidal flows, the Coriolis Force can drag the ebb flow southeasterly, and so influence sediment transport paths at the estuarine scale. The Coriolis Force is limited in the inner river mouth, but substantial at and in the outer river mouth area when gradually free of estuarine topographic constraints. The Coriolis Force causes an offset in propagation of in-out flow directions at the river mouth area to form a slack water setting prone to estuarine siltation. Using the present approach also enables explanation of the morphological development of the Holocene Yangtze delta-coast that extends to the southeast. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we estimate the inputs of nitrogen (N) and exports of dissolved inorganic nitrogen (DIN) from the Changjiang River to the estuary for the period 1970-2003, by using the global NEWS-DIN model. Modeled DIN yields range from 260 kg N km-2 yr-1 in 1970 to 895 kg N km-2 yr-1 in 2003, with an increasing trend. The study demonstrated a varied contribution of different N inputs to river DIN yields during the period 1970-2003. Chemical fertilizer and manure together contributed about half of the river DIN yields, while atmospheric N deposition contributed an average of 21% of DIN yields in the period 1970-2003. Biological N fixation contributed 40% of DIN yields in 1970, but substantially decreased to 13% in 2003. Point sewage N input also showed a decreasing trend in contribution to DIN yields, with an average of 8% over the whole period. We also discuss possible future trajectories of DIN export based on the Global NEWS implementation of the Millennium Ecosystem Assessment scenarios. Our result indicates that anthropogenically enhanced N inputs dominate and will continue to dominate river DIN yields under changing human pressures in the basin. Therefore, nitrogen pollution is and will continue to be a great challenge to China. [ABSTRACT FROM AUTHOR]

In 2002, China launched the South-to-North Water Transfer Project after completing a 50-year feasibility study. By 2050, the three-route (i.e., East, Middle, and West) project will be capable of transferring 44.8 billion m3/year of water from the water rich Yangtze River to the arid north to alleviate water shortage and help secure a balanced social and economic development across the nation. However, diversion of such a large quantity of water could profoundly change the riverine environment of the upper Yellow River and the lower reach of the Han River, a tributary of the Yangtze River and the water supplying area of the project’s Middle Route, because of changes in the annual discharge. Secondary salinization seems inevitable in the water receiving areas of the North China Plain, and decrease in the discharge of the Yangtze River will result in seawater intrusion into the Yangtze Delta. This paper describes the project and discusses its environmental implications. Additionally, a long-term monitoring strategy under the umbrella of the Chinese Ecological Research Network is proposed for environmental monitoring. [ABSTRACT FROM AUTHOR]

The Eurocentric growth model has been the basic workhorse for numerous Chinese economic historians. This deep seated Eurocentric paradigm is concerned mainly with conterfactuals and tends to ignore past reality. To illustrate the problems of this Eurocentric approach, this paper examines the rural economy of Jiangnan, also known as the Yangzi Delta, during late imperial times. A main characteristic of the villages in the Wuxi county in Jiangnan were the mixture of the rural–urban lifestyle and development. Jiangnan's developmental patterns, in the Song and the Qing dynasty, from the Maoist period (pre-1979) to post-1979 development, contrast sharply with the predictions of the Western development models. [ABSTRACT FROM AUTHOR]

Container ports located in a delta of navigable waterways generally strive to develop the inland river services as a competitive transport mode, with a view to serving local and distant hinterland regions. The spatial and functional development of river-based container networks is location-specific and time-specific. While each barging network and associated seaport system has its own dynamics, similarities in development patterns cannot be excluded. This paper discusses similarities and dissimilarities between the spatial and the functional development of the container river service networks of the Yangtze River and the Rhine River. It is shown that the Yangtze service network has the tendency to converge, in more than one aspect, with the (historical) development pattern of inland container services in the Rhine basin. [ABSTRACT FROM AUTHOR]

Soil erosion in the upper reaches of the Yangtze River in China is a major concern and the Central Government has initiated the Grain-for-Green Programme to convert farmland to forests and grassland to improve the environment. This paper analyses the relationship between land use and soil erosion in Zhongjiang, a typical agricultural county of Sichuan Province located in areas with severe soil erosion in the upper reaches of the Yangtze River. In our analysis, we use the ArcGIS spatial analysis module with detailed land-use data as well as data on slope conditions and soil erosion. Our research shows that the most serious soil erosion is occurring on agricultural land with a slope of 10∼25 degrees. Both farmland and permanent crops are affected by soil erosion, with almost the same percentage of soil erosion for corresponding slope conditions. Farmland with soil erosion accounts for 86⋅2 percent of the total eroded agricultural land. In the farmland with soil erosion, 22⋅5 percent have a slope of <5 degrees, 20⋅3 per cent have a slope of 5∼10 degrees, and 57⋅1 percent have a slope of >10 degrees. On gentle slopes with less than 5 degrees inclination, some 6-percent of the farmland had strong (5000∼8000 t km-2y-1) or very strong (8000∼15000 t km-2y-1)erosion. However, on steep slopes of more than 25 degrees, strong or very strong erosion was reported for more than 42 per cent of the farmland. These numbers explain why the task of soil and water conservation should be focused on the prevention of soil erosion on farmland with steep or very steep slopes. A Feasibility Index is developed and integrated socio-economic assessment on the feasibility of improving sloping farmland in 56 townships and towns is carried out. Finally, to ensure the success of the Grain-for-Green Programme, countermeasures to improve sloping farmland and control soil erosion are proposed according to the values of the Feasibility Index in the townships and towns. These include: (1) to terrace sloping farmland on a large scale and to convert farmland with a slope of over 25 degrees to forests or grassland; (2) to develop ecological agriculture combined with improving the sloping farmland and constructing prime farmland and to pay more attention to improving the technology for irrigation and cultivation techniques; and (3) to carry out soil conservation on steep-sloping farmland using suggested techniques. In addition, improving ecosystems and the inhabited environment through yard and garden construction for households is also an effective way to prevent soil erosion. [ABSTRACT FROM AUTHOR]

This paper provides an evaluation of current arrangements made for compensation and resettlement to farmers who will be displaced by the construction of the Three Gorges Project (TGP) on the Yangtze River. Kaixian County is used as a case study. Under present regulations the specific value of peri–urban land is underestimated, neither cash–in–hand arrangements nor land–for–land swaps are adequate. There are other problems. The availability of suitable land for resettlement is scarce and rarely of equivalent quality. The inflexibility of the ‘household responsibility system’ contributes to the problem. It is suggested that some of those facing displacement should be encouraged to accept resettlement in places at considerable distance from their current homes and that a more creative approach should be taken to the issue of compensation to enable people to develop their trade and business skills. [ABSTRACT FROM AUTHOR]

In the East Asian monsoon region, eolian deposits widely distributed in the middle-lower reaches of the Yantgze River are among the best materials available for studies on Quaternary climate change in the subtropical zone of Southern China. Typical eolian deposits in this region include upper Xiashu Loess (XL) and underlying Vermiculated Red Soil (VRS) layers. In this paper, chronological and paleoclimatic studies are conducted on an eolian deposit sequence near Jiujiang (JJ) city in northern Jiangxi province. A magnetostratigraphic study, combined with optically stimulated luminescence (OSL) dating, is conducted on the JJ section and provides further evidence that eolian deposits in the middle-lower reaches of the Yangtze River have been formed since the late Early Pleistocene, and that the boundary age between the XL and VRS layers is about 300-400 kaBP. In grain-size records of the JJ section, the median grain-size and content of the >30 μm size fraction increase sharply after 300-400 kaBP, representing an East Asian winter monsoon intensification event. Further pollen analysis reveals differing pollen assemblages before and after 300-400 kaBP: there is an evident increase in plants adapted to grow in a warm humid environment after 300-400 kaBP, implying an increase in precipitation caused by intensification of the East Asian summer monsoon. Global ice volume and uplift of the Tibet Plateau (TP) are regarded as crucial factors influencing variations of the East Asian monsoon on a long-term scale. The deep-sea δ18O record, which reflects variations in global ice volume, shows no obvious change after 300-400 kaBP. Moreover, the influence of global ice volume changes on the East Asian summer and winter monsoons is inverse; the global ice volume increase (decrease) implies a strengthened (weakened) winter monsoon and weakened (strengthened) summer monsoon. We therefore interpret the coupled intensifications of the East Asian summer and winter monsoons at about 300-400 kaBP to the uplift of the TP in the Middle Pleistocene. This climate event is also documented in eolian deposits from the southern margin of the Chinese Loess Plateau (CLP) and from the desert-loess transitional belt. However, it is not recorded in the loess-paleosol sequences from the central part of the CLP, thereby indicating differing climate responses to TP uplift in different regions, which requires further study. [ABSTRACT FROM AUTHOR]

Ground‐level ozone (O3) and atmospheric fine particulate matter (PM2.5) pollution are the major challenges for continually improving air quality in the Yangtze River Delta (YRD) region of China. Understanding regional transport patterns of PM2.5 and O3 pollution is essential for the development of regional cooperative prevention strategies. This study shows the annual concentration of PM2.5 in the YRD decreased by 18.5% from 2015 to 2018, while the mean values of the daily maximum 8‐hr average (MDA8) O3 concentration from March to October increased by 16.3%. A complex network method is utilized to investigate the regional transport of PM2.5 and O3 in different grid cells (nodes). The source apportionment method within the chemistry transport model is applied to verify the reliability of the complex network method. Interregional and intraregional transport play an important role in both PM2.5 and O3 over the YRD. The northern part of the YRD contributes much more than other areas, while the central part of the YRD, especially the southern part of Jiangsu, is the largest contributor of O3 in the YRD in the summer, accounting for about 70%. Intraregional transport plays more of a major role in increasing PM2.5 pollution than O3 pollution. This study not only verifies the transport patterns of heavy pollution through the complex network method and traditional source apportionment technology, it also reveals that both methods provide great potential in understanding transport patterns and air pollution relationships, which are the solid foundation for emission mitigation in the YRD region. Key Points: Complex network method provides a foundation for an in‐depth analysis of regional transport with chemical transport model at grid levelThe results show that the Suxichang and Hangjiahu areas are the most prominent contributors of both PM2.5 and O3 in the Yangtze River Delta (YRD)The southern Huangshan and the border of Jinhua and Lishui are the major receptors for PM2.5 and O3 in the YRD [ABSTRACT FROM AUTHOR]

A comparison is presented between groundwater storage trends derived from Gravity Recovery and Climate Experiment (GRACE) satellite measurements and trends derived from unregulated river baseflow observations in 19 catchments in tributaries of the Central Yangtze River. The two sets of trends are well correlated with a coefficient of r = 0.64, but the baseflow‐derived trends were found to be on average about 33% smaller than those based on the GRACE measurements. Although other factors undoubtedly play a role, the difference in trend magnitudes of the two sets of trends is concluded to be mainly due (i) to remaining uncertainties and complexities in GRACE data processing and (ii) to the likely gradual shrinking of the contributing catchment areas during the baseflow recession process. The present findings should be useful in extending GRACE measurements to longer periods on the basis of long‐term streamflow measurements and in recovering missing data. Key Points: Groundwater storage change estimates obtained by GRACE satellite measurements are compared with baseflow recession‐based estimatesWhile the trends were very similar, on average, the baseflow based trends were about 33% smaller than those based on GRACE dataThe characteristic drainage time scales of the investigated catchments in China were mostly consistent with observations elsewhere [ABSTRACT FROM AUTHOR]

Abstract: Water‐level variations are an internal aspect of lake ecosystems that play a key role in structuring aquatic diversity and providing ecosystem services. In this study, the hydrologic alteration of Dongting Lake induced by the Three Gorges Dam (TGD) was assessed using indicators of hydrologic alteration and range of variability approach. The results demonstrate a declining trend in autumn water level (0.52–2.26 m) and 5–35 days' advancement for date of minimum annual water level because of the impound of water by the TGD in early autumn. The spatial patterns in the degree of the indicators of hydrologic alteration were different among the sub‐lake regions. Annual minimum water level and timing of annual extreme water level suffered a high degree of alteration in the eastern part of the lake, whereas autumn water level, date of minimum water level, and number of reversals in the western part of the lake showed a high degree of alteration. The average integrated degree of hydrologic alteration (D0) for Dongting Lake was 50.40%, indicating that the hydrologic regime suffered a moderate alteration. The most ecologically relevant hydrologic indicators are critical for understanding eco‐hydrology. On the basis of principal component analysis, the five selected ecologically relevant hydrologic indicators were 90‐day minimum, date of minimum, high pulse duration, date of maximum, and May water level. Further studies are required to understand the impact of the TGD on water conditions in Dongting Lake, especially related to the response of the aquatic ecosystem. [ABSTRACT FROM AUTHOR]

ABSTRACT: Using the National Centers for Environmental Prediction–National Center for Atmospheric Research reanalysis and National Oceanic and Atmospheric Administration extended reconstructed sea surface temperature (SST) data sets, we examine the preceding factors in the Atlantic Ocean contributing to summer high temperature anomalies over the lower reaches of the Yangtze River basin–Jiangnan (LRYB–JN) region. We find that summer LRYB–JN surface air temperature (SAT) anomalies are highly correlated with, and physically connected to, the preceding winter SST and SAT anomalies in the tropical western Atlantic (TWA) region [(10°–30°N, 60°–35°W) and (0°–10°N, 50°–35°W)]. The effect of preceding winter thermal conditions in the TWA region can be explained by the following two mechanisms. Coupled with SST, positive TWA SAT anomalies can persist from the preceding winter to summer and excite a zonal wave train at middle latitudes extending from the Atlantic to Eurasia, with a deep and stable high pressure anomaly centred over the LRYB–JN region. As a result, high temperature anomalies occur over the LRYB–JN region. In addition to the above mechanism, the TWA SST–SAT coupled anomalies also exert an impact on summer LRYB–JN SAT by modulating the tropical Indian Ocean (TIO) SAT and SST variation, which causes summer LRYB–JN SAT anomalies. Given the contributions of TWA SAT anomalies, independent of and in concert with the TIO SAT variation, we define a preceding winter TWA–TIO SAT index, which measures the concurrent variation of TWA and TIO SATs. The preceding winter TWA–TIO index is more significantly correlated with the summer LRYB–JN SAT and therefore can reflect the latter better than the individual TWA or TIO SAT index. [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]

During the summers of 2009 and 2013, seawater pH and concentrations of dissolved oxygen, inorganic carbon, and nutrients were measured off the Changjiang estuary in the East China Sea. The 2009 cruise captured the effects of Typhoon Morakot; the 2013 cruise sampled more typical conditions (no typhoon). Data from both years indicate a close correlation between high primary productivity in surface waters and hypoxia in bottom waters. Based on these observations, we developed a conceptual model to guide an exploration of processes contributing to the formation of summertime bottom hypoxia. A mixing-model analysis of the 2009 data identified a surface diatom bloom as the major (70-80%) source of the organic carbon that decomposed and ultimately led to bottom water hypoxia. Within the Changjiang River plume, depth-integrated net biological production in the water column was 1.8 g C m−2 d−1, indicating strong autotrophic production, which in turn led to a high respiration rate of 1.2 g C m−2 d−1 in the bottom water. During both cruises, strong surface-to-bottom physical and metabolic coupling was evident. In 2009, storm-driven inputs of nutrients from elevated river discharge and strong vertical mixing helped to fuel the rapid development of a surface diatom bloom. Afterwards, stratified conditions re-established, newly formed labile organic matter sank, and bottom water oxygen was quickly consumed to an extent that hypoxia and acidification developed. To our knowledge, the observed rate of hypoxia and acidification development (within 6 d) is the fastest yet reported for the Changjiang River plume. [ABSTRACT FROM AUTHOR]

Using the finite volume method, a 2-D water-sediment coupled model was developed to investigate the transport mechanisms of water and sediment in Poyang Lake, the largest river-connected lake in China. Simulating water and sediment transport processes in an average water year revealed that the total volume of water and the amount of suspended sediment transported from the five main rivers upstream of Poyang Lake were approximately 1.56 × 1011 m3 and 1.25 × 107 t, respectively. The outputs of water and sediment from the lake to the downstream Yangtze River were approximately 2.17 × 1011 m3 and 1.53 × 107 t, respectively. During the wet season, especially between July and September, nearly 1.06 × 1010 m3 of water and 1.89 × 106 t of suspended sediment were transported upstream from the Yangtze River into the lake due to the high external water levels, which accounted for 4.88% and 12.35%, respectively, of the total annual transport from the lake into the Yangtze River. [ABSTRACT FROM AUTHOR]

The impact of urbanization for a summertime rainstorm process in the Yangtze River Delta was investigated based on two 96 member ensembles using the Weather Research and Forecasting (WRF) model. Results show that the increase of precipitation mainly occurs downwind of the city belt in this region. The increase and decrease of precipitation forms two zigzag belts in the precipitation area. The t-test illustrates that the discrepancies of near-surface environment around the city belt, the precipitation downwind of the city belt as well as the atmospheric variables in the lower troposphere over the rain belt, caused by urbanization, is significant in such a short-term rainstorm process. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

The diverse hydro-climate between northern and southern China causes serious complications related to increasing food demand, declining water availability, and increasing flood risk in Changjiang and Yellow River basins. The huge projects of Three Gorges Dam (TGD) for diminishing flood and South-to-North Water Transfer Project (SNWTP) for driving water from Changjiang to Yellow and Hai Rivers to compensate for an imbalance of environmental resources will not necessarily solve all of the problems that they were originally intended to address. A sophisticated eco-hydrological model is required to evaluate the optimum amount of transferred water associated with these projects, together with socio-economic and environmental consequences. For this purpose, the process-based National Integrated Catchment-based Eco-hydrology (NICE) model was modified to couple with complex sub-systems in irrigation, stream junction, reservoir operation, and water transfer, to develop coupled human and natural systems and evaluate cause and effect of uneven water resources. The model clarified the impact of irrigation on eco-hydrological processes and predicted hydrologic change after TGD and SNWTP to estimate whether dilemmas between water stress, crop productivity, and ecosystem degradation would diminish. The result also showed the missing role of surface water - groundwater interactions and lateral subsurface flow, usually not considered important by assuming stationarity in previous researches of continental scales. A heterogeneous pattern of Time-Integrated Normalized Difference Vegetation Index gradient in agricultural fields helped to estimate uneven crop yield and its relation to water availability. This integrated approach will have some roles not only to re-consider this complex process from the view point of hydrologic and biogeochemical cycles, but also to clarify how the substantial pressures of complicated problems can be overcome by effective trans-boundary solutions. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Yangtze finless porpoise ( Neophocaena asiaeorientalis asiaeorientalis) is a highly threatened cetacean endemic to the middle and lower reaches of the Yangtze River that has suffered a dramatic decline in recent decades. We characterize and quantify recent distribution patterns of porpoises in the Yangtze River in order to facilitate strategic management of existing in situ cetacean reserves and maximize effective utilization of limited conservation resources. We calculated porpoise relative abundance (encounter rate) using a 1-km moving average along the Yangtze main stem based on a combined visual and acoustic survey conducted in 2006. We then evaluated conservation priority areas based on encounter rates along the river. High-porpoise density areas (> 0.20 porpoises km−1) cover approximately one-third (33.9%, 599 km) of the survey area and contain approximately two-thirds of the porpoise population, making them priority areas for porpoise conservation. In contrast, low-porpoise density areas (≤ 0.05 porpoises km−1) cover 28.8% (509 km) of the survey area but contain only 4.5% of the porpoise population, and may already be of little value for porpoise conservation. Five high-priority porpoise conservation sites and five sections that now contain few or no surviving porpoises are identified. Proposed spatial modifications to existing reserves and associated conservation recommendations are made for five existing protected areas along the Yangtze main stem, and we emphasize that some additional river sections should urgently be designated as new protected areas given their high porpoise density. Our approach for identifying conservation priorities may provide lessons for reserve design and management in other protected area networks. [ABSTRACT FROM AUTHOR]

Solar radiation is the principal and fundamental energy for many physical, chemical and biological processes. However, it is measured at a very limited number of meteorological stations in the world. Estimation of solar radiation from measured meteorological variables offers an important alternative in absence of measured solar radiation. In this work, 20 developed models using measured meteorological variables are explored to estimate monthly average daily solar radiation at 13 stations in Yangtze River Basin in China. Two scenarios are considered. When sunshine duration is available, monthly average daily atmospheric water vapor pressure, relative humidity and precipitation do not contribute to the improvement in estimation accuracy of the sunshine-based models. It is therefore unnecessary to take them into account, and the newly developed model 6 is proposed and can provide a good method for the estimation of monthly average daily solar radiation in the study area. If sunshine duration is not available, inclusion of monthly average daily atmospheric water vapor pressure, relative humidity and multiplication maximum by minimum ambient temperatures can significantly improve the estimation accuracy of the temperature-based models. While monthly average daily precipitation does not contribute to the improvement in estimation accuracy. And model 20 is proposed and it is more applicable in area with larger ambient temperature range. Copyright © 2012 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

This study investigated the variations of dissolved N2O and emissions over diurnal and seasonal temporal scales in 2009, as well as the time series of riverine N2O export to estuary and emission to atmosphere in response to increasing anthropogenic nitrogen loads in the Changjiang River. For the diurnal study, N2O concentrations ranged from 0.26 to 0.34 and from 0.44 to 0.52 μg N-N2O L-1 in August and October 2009, respectively. The dissolved N2O was supersaturated with a mean value of 197%. Studies on N2O emissions, also taken in August and October, ranged from 2.67 to 11.6 and from 6.72 to 15.2 μg N-N2O m-2 h-1, respectively. For the seasonal study (June through December 2009), N2O concentrations ranged from 0.34 to 0.72 μg N-N2O L-1 and were supersaturated in all the samples (average 212%). N2O emissions ranged from 1.87 to 40.8 μg N-N2O m-2 h-1. Our study found no significant differences in diurnal patterns of N2O saturation but detected significant difference in seasonal patterns of N2O saturation: higher during summer while lower during autumn and winter. We found a significant relationship between dissolved N2O and river nitrate, which can predict the variation of N2O concentrations in the River. The net production of N2 ranged from 0.01 to 0.47 mgN-N2L-1. These excess N2 values were significantly correlated to the N2O production and are suggestive of denitrification in me river. Applying the Global News model to the river system using measures taken during the 1970 to 2002 period, we estimated N2O emissions to atmosphere increased from 330 to 3650 ton N-N2O yr-1. During that same 1970-2002 period, N2O exports to estuary increased from 91 to 470 ton N-N2O yr-1. Taken together, the findings reported here suggest that both the river N2O concentrations and emissions would increase in response to rising anthropogenic nitrogen loads. Our study showed that the mean emission factor based on the ratio of the total N2O flux to NOJ" flux is four times greater than the value of 0.0025 obtained with the methodology recommended by the Intergovernmental Panel on Climate Change. Thus, our findings reflect the open river channel rapid exchange of gases with the atmosphere. [ABSTRACT FROM AUTHOR]

Hydrodynamic flow fields affect the ecological processes such as the water diversity and the distribution of organisms. Understanding the hydrodynamic and ecological processes is critical for the restoration and protection of especially fragile ecological habitats in river systems. This study uses turbulent flow to characterize the ecological behaviour of Chinese Sturgeon ( Acipenser sinensis) in the Yangtze River. The Delft3D-Flow model, which is first validated with field-measured data, is used to simulate the flow field within spawning habitats of Chinese Sturgeon, downstream of Gezhouba Dam. The model-simulated turbulent kinetic energy (TKE) and its distribution pattern are then used to characterize the hydraulic environment of the fish's spawning habitat. For the spawning habitat, downstream of Gezhouba Dam, the lower limit of TKE for the Chinese Sturgeon egg mass field is 0.025 m2/s2, which occurs at a velocity less than 1.7 m/s. Chinese Sturgeon prefers habitats with TKE range of 0.010 ~ 0.015 m2/s2 for resting. This suggests that discharge regimes provide the basis for ecological regulation of the Three Gorges Reservoir and the scientific reference for river management. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

From 2006 to 2009, 27 ultrasonic-tagged wild adult Chinese sturgeon Acipenser sinensis [eight males, 19 females; total length ( LT) range = 245-368 cm] were captured on the spawning ground just downstream of Gezhouba Dam (GZD) in the Yangtze River. Twenty-six individuals were tracked for 7 to 707 days (mean number of relocations = 859; range = 3-4549). Acipenser sinensis movements were divided into four categories: (1) spawning migration, two tagged A. sinensis (one female and one male) returned to the Yangtze River and migrated from the Yangtze Estuary (river kilometer, rkm, 0) to the spawning ground (1678 rkm) between June and October. Their mean upstream ground speed was 1·41 km h−1 (range = 0·26-2·35 km h−1). The speed of the male was faster than the female; (2) pre-spawning holding, four of five females tagged in November 2008 stayed within 1678·00-1674·15 rkm for c. 1 year before the spawning period; (3) spawning movements, all A. sinensis swam mostly from the tailrace of the GZD (1678 rkm) to the Miaozui (1674·15 rkm) reach and some moved downstream c. 18·21 rkm (range = 3·93-24·64 rkm), but then, returned upstream to the GZD. Most tagged A. sinensis were on the spawning ground on the day when the spawning occurred; (4) post-spawning migration males ( n = 6) and females ( n = 2) departed the spawning area on a different time schedule, females leaving before males. The mean seaward ground speed of six A. sinensis was 4·87 km h−1 (range = 0·68-7·60 km h−1). There were no significant differences ( P > 0·05) in ground speeds among reaches or between sexes within reaches between telemetry receivers. These broad spatiotemporal scale results will help establish an effective protection strategy for the species in the Yangtze River. [ABSTRACT FROM AUTHOR]

The Yangtze is the largest river in Asia and its water composition reflects the activities of about 400 Mio people in its catchment. Its chemical loads have a large impact on the biogeochemistry of the East China Sea. We discuss and quantify the annual dynamics of major ions, nutrients, and trace elements from samples collected monthly at Datong Station from May 2009 to June 2010. The Yangtze today carries 192 × 106 tons of total dissolved solids annually to the East China Sea, which is an increase of 25% compared to the average of 1958-1990. While the loads of dissolved silica (SiO2), dissolved inorganic carbon (DIC), Ca2+ and Mg2+ compared well with the long-term averages since the 1950s, loads of Na+, Cl-, SO42-, have tripled since 1958-1990. The increase of SO42- is attributed to the burning of coal in the catchment, and 18% of the F- load is estimated to originate from this source. The increase of Na+ and Cl- loads may be anthropogenic as well. The load of dissolved inorganic nitrogen (DIN) has increased 15 fold since the early measurements around 1970 and amounts to 1.6 Mt-N/yr today. The particulate concentrations of the typical anthropogenic trace metals Cd, Cr, Cu, Ni, Pb, and Zn showed enrichment factors between 0.7 - 7 compared to the natural background. Their annual peak concentrations all exceeded the quality targets recommended by the EC up to two times. However, the load of trace elements at Datong decreased by 73-86% (As: 50%) in the past ten years. [ABSTRACT FROM AUTHOR]

A one-year study was carried out to investigate the seasonal fluxes and source variation of organic carbon transported by two major Chinese rivers, the Yellow River and Changjiang. In 2009, the Yellow River and Changjiang transported 3.20 × 1010g and 1.58 × 1012 g DOC and 3.89 × 1011g and 1.52 × 1012 g POC, respectively. The dominant input of the terrestrial organic matter occurred during the high discharge period from June to July for the Yellow River and from June to August for Changjiang, accounting for 36-44% of the DOC and 72-86% of the POC transported by the two rivers in 2009. The Yellow River transported much higher concentrations of inorganic carbon than organic carbon, while a reverse trend was found in the Changjiang, indicating the different sources of carbon discharged by the two rivers. Using radiocarbon and stable carbon isotope measurements, we identified the different sources and seasonal variations of organic carbon transported by the Yellow River and Changjiang. The Yellow River carried old POC with radiocarbon ages ranging from 4000 to 8000 years, while POC transported by Changjiang had a relatively younger 14C age ranging from 800 to 1060 years. The 14C ages of DOC were relatively younger (305-1570 years) and showed less variation between the two rivers. The seasonal variations found in 14C ages of DOC and POC indicate that a large fraction of recent-fixed labile organic carbon was transported by the two rivers in the spring and summer months. The different sources and seasonal variations in both fluxes and sources of organic carbon transported by the Yellow River and Changjiang could have an important influence on the biogeochemical cycle and ecosystems in the estuaries and adjacent coastal waters of the East China Sea. [ABSTRACT FROM AUTHOR]

ABSTRACT Largemouth bronze gudgeon ( Coreius guichenoti), a fish species once abundant in the Yangtze River, has been rapidly declining in recent years. One important factor, among many, is the interruption of the free-flowing rivers by dams. To obtain data that can be applied to the design of an effective fishway for C. guichenoti and other species in the fish community, a laboratory study of juvenile C. guichenoti's swimming ability and energetics was conducted in a flume-type respirometer equipped with a high-speed video camera system to record swimming behavior. The critical swimming speed ( Ucrit), standard metabolic rate ( SMR), and maximum metabolic rate ( MO2,max) were determined during steady swimming at four water temperatures (10, 15, 20, and 25°C). A power function accurately describes the relationship between oxygen consumption rate ( MO2) and swimming speed ( U) at the four temperatures. The Ucrit, SMR, MO2,max, and metabolic scope increased with increasing temperature. The relationship between cost of transport ( COT) and U was characteristically inverse bell-shaped, with minimum COT at Uopt = 4.5-5.0 body lengths per second (bl sec−1). This investigation provides data on the swimming ability of C. guichenoti that will add to the basic science required for fishway design. J. Exp. Zool.317:294-302, 2012. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

The Yangtze finless porpoise ( Neophocaena asiaeorientalis asiaeorientalis) is an endangered freshwater porpoise subspecies unique to the Yangtze River basin. Seasonal variations in local distribution of the animal, as well as fish presence, sand dredging, ship navigation, and bridges were examined as potential factors affecting the occurrence of the animals. Passive acoustic surveys were performed regularly from May 2007 to August 2010, near the conjunction of the Yangtze River and Poyang Lake. The distribution of the porpoises was seasonally site-specific. In May and August, the animals were detected more often at river junctions than in the lake, but vice versa from November to February. The rate of the porpoise detection was significantly higher in areas of fish presence than in areas of absence. The number of porpoises detected did not differ significantly between the sand dredging operation and the prohibition period (in 2008), although the number of vessels obviously declined in 2008. Ship traffic and bridges also did not appear to affect the presence of porpoises. These results showed the relative importance of the various environmental factors, which is important for conservation of not only Yangtze finless porpoise but also endangered isolated cetaceans. [ABSTRACT FROM AUTHOR]

Using generalised Pareto distribution (GPD) function, the regional characteristic of extreme monthly low temperatures (EMLT) distribution during 1960-2007 in China is studied, and the potential impact of climate warming on EMLT regions in China is analysed. The results show that EMLT space distribution has latitudinal difference in China. Higher-value EMLT events are likely to happen in northeastern and southwestern China, while EMLT variability and occurrence probability of high-value EMLT events are less in the Yangtze and Huaihe River basin and the coast of southern China. The study indicates that climate warming impacts EMLT, and EMLT distribution responds to the climate warming over most areas of China. Copyright © 2010 Royal Meteorological Society [ABSTRACT FROM AUTHOR]

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]

Suspended sediment dynamics during the period 1964-1985 are examined along the mainstem of Changjiang (Yangtze River). The period represents a basin condition prior to major changes in land management policy and dam building on the river's mainstem. The downstream sediment dynamics reflect basin geology and topography and channel morphology. Sediment exchange within the mainstem was calculated by the development of reach sediment balances that reveal complex temporal and spatial patterns. There is relatively little sediment exchange in the upper, bedrock controlled reaches, with systematic increases in the downstream alluvial reaches. Degrading, transfer, and aggrading reaches were identified. Relations between input and output in all reaches were significant but no relation was found between sediment exchange and input/output. Comparison between 'short-term' (22 years) and 'long-term' (52 years) records demonstrates the importance of the record length in studying the suspended sediment dynamics in a large fluvial system. The longer record yielded better correlation and different trends than the shorter record. Sediment transfer (output/input ratio) changes downstream: the dominance of the upstream contributing area in sustaining the appearance of net degradation through most of the river system highlights the importance of reach length on characterisation of suspended sediment dynamics in large fluvial systems. [ABSTRACT FROM AUTHOR]

Few investigations have been made on the impact of elevated ozone (O) concentration on methane (CH) emission from rice paddies. Using open-top chambers in situ with different O treatments, CH emissions were measured in a rice paddy in Yangtze River Delta, China in 2007 and 2008. There were four treatments applied: charcoal-filtered air (CF), nonfiltered air (NF), and charcoal-filtered air with different O additions (O-1 and O-2). The mean O concentrations during the O fumigation were 19.7, 22.6, 69.6 and 118.6 ppb in 2007 and 7.0, 17.4, 82.2 and 138.3 ppb in 2008 for treatments CF, NF, O-1 and O-2, respectively. The rice yields, as compared with CF, were reduced by 32.8% and 37.1%, 58.3% and 52.1% in treatments O-1 and O-2 in 2007 and 2008, respectively. The diurnal patterns of CH emission varied temporally with treatments and there was inconsistence in diurnal variations in CH emissions from the paddy field. The daily mean CH emissions were significantly lower in treatments O-1 and O-2 than those in treatments CF and NF. Compared with CF treatment, CH emissions from the paddy field were decreased to 46.5% and 38.3%, 50.6% and 46.8% under treatments O-1 and O-2 in the whole growing seasons of 2007 and 2008, respectively. The seasonal mean CH emissions were negatively related with AOT40 (accumulative O concentration above 40 ppb; P < 0.01 in both years), but positively related to the relative rice yield (reference to CF; P < 0.01 in 2007 and P < 0.001 in 2008), aboveground biomass ( P < 0.01 in both years) and underground biomass ( P < 0.01 in 2007 and P < 0.05 in 2008). The decreased CH emission from the rice paddy due to an increased O exposure might partially mitigate the global warming potential induced by soil carbon loss under elevated O concentrations. [ABSTRACT FROM AUTHOR]

Summary 1. The Upper Yangtze River drains a catchment of c. 1 million km2 from its headwaters on the Tibetan Plateau to the city of Yichang below the Three Gorges Dam. The Upper Yangtze River Basin supports a diverse aquatic fauna, including 118 endemic fish species. The river basin has a long history of human use and environmental alteration and is further threatened by the demands of a large population and rapid economic development. 2. We identified a set of areas that, with adequate protection and/or management, might maintain the aquatic biodiversity and ecological processes representative of the basin. Methods were developed to address the scope and scale of conservation planning across the entire Upper Yangtze Basin in a short time-frame using available data. The analytical framework is a watershed hierarchy of five catchment size classes derived from a globally available hydrography dataset called HydroSHEDs. Catchments were assigned to ecosystem types according to catchment area and patterns of climate, catchment morphology, geology and sources of water. Catchments were also ranked by ecological condition using an index of cumulative anthropogenic impacts. 3. We defined conservation priorities as a combination of expert-designated focal areas that support endemic fish assemblages and habitat in good condition; sites selected with the conservation planning software MARXAN to meet representation targets for ecosystems and optimise ecological condition and longitudinal connectivity; and a set of rivers selected to provide refugia for fishes affected by a hydropower and flood control infrastructure development project. 4. Areas selected as conservation priorities include 3200 km (27% of total length) of large rivers, 9900 km (39% of total length) of small rivers and 30% of small stream catchments in the basin. To evaluate the degree to which the set of conservation priority areas supports threatened and endemic fishes, we conducted a gap analysis using survey records and historic range maps of 131 threatened and/or endemic fish species. The conservation priority areas contain survey records or portions of the known historic range of 116 (88%) of the 131 species we evaluated, with an average of 49% of the survey records and/or 26% of the known historic ranges of each species. [ABSTRACT FROM AUTHOR]

Hydrological disconnection of floodplains from rivers is among the top factors threatening river-floodplain ecosystems. To keep enough floodplain area is of great importance to biodiversity conservation. In the Yangtze River floodplain, most lakes were disconnected from the mainstream by dams in 1950-1970s. By analysing fish diversity data, we aim at determining the effects of river-lake disconnection on fish diversity, at estimating the minimum protected area of river-connected lakes and at proposing a holistic strategy for fish conservation in the mid-lower reaches of the river. The Yangtze River floodplain, China. We collected recorded data of fish diversity of 30 Yangtze floodplain lakes. Species-area relationships were analysed and compared between river-connected and river-disconnected lakes. Cumulative species-area models were constructed to estimate the minimum protected area of river-connected lakes. River-lake disconnection reduced fish diversity of Yangtze lakes by 38.1%, so that the river-connected lakes play an important role in maintaining the floodplain biodiversity. The minimum protected area of river-connected lakes was estimated to be 14,400 km. Therefore, we should not only protect the existent connected lakes of 5500 km, but also reconnect disconnected lakes of at least 8900 km in the Yangtze basin. Species-area relationships are of importance in reserve design. We suggest that cumulative species-area model might be more suitable for ecosystems with high connectivity among regions such as floodplains. As the Yangtze River floodplain is an integrative ecosystem, we suggest establishing a holistic nature reserve in the mid-lower basin for effective conservation of biodiversity. [ABSTRACT FROM AUTHOR]

Four major reaches of Chiangjang (Yangtze River) were analyzed for the period 1956-2007 in terms of long-term trends in suspended sediment gain and loss in each reach, the relation of input and output to within-reach sediment fluxes, and the impacts of dam construction on reach sediment dynamics. The temporal and spatial patterns of within-reach sediment dynamics correspond closely with river morphology and also reflect basin conditions over the past few decades; thus they are conditioned by coeval trends in climate, hydrology, and land use. The study period encompasses both unusually wet years (e.g., 1998) and unusually dry periods (e.g., 2006). There are suggestive coincidences between changes in the suspended sediment regime and innovations in land use, sediment mining, and dams. The relatively strong statistical relation between sediment input and output for each of the four study reaches, and weak relations between storage and output, imply that most sediment supplied to each reach is delivered from upstream and that relatively small amounts of sediment are recruited within each reach. Cumulative departure plots reveal epicycles of sediment exchange varying from 15 to 40 years, implying a characteristic fine sediment storage time on the order of decades. Shorter epicycles (5-8 years) are commonly related to sediment influx associated with major floods. [ABSTRACT FROM AUTHOR]

The food web of the benthic macroinvertebrate community of the Tanqigou Stream - a subtropical forested headwater stream of the Yangtze River basin - was investigated for the first time. The results indicated that the stream was mainly a detritus-based system, with its functionality being highly dependent on allochthonous input of organic matter. Vascular plant detritus, filamentous algae, diatoms and fungi were also important food resources for the macroinvertebrate community in the stream. Temporal and spatial patterns of ingestion of four mayflies (which were the dominant species) demonstrated that there was little difference in feeding selection, but significant variations in ingestion patterns were observed, during different seasons and at different sampling sites. Nevertheless, the rates of ingestion of the four mayflies were generally stable and independent of the season or the site. The macroinvertebrate food web encompassed five basic food resources; four top predator species, and 27 intermediate non-predator consumers. The predator-prey ratio was 0.36; the total number of linkages 152; the trophic connectance 0.16; the maximum chain length three; and the mean chain length 2.21. A quantitative assessment of the energy flux along the major food web pathways indicated that organic matter pathways were mainly formed by weak linkages (36), which accounted for 60.31% of the total linkages (63) and that a few pathways accounted for most of the flow of organic matter. This suggests that Tanqigou Stream is similar to streams that are mainly dependant on detritus-based- and allochthonous-input of organic matter. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Comprehensive evaluation of the water environment for effective water quality management is complicated by a considerable number of factors and uncertainties. It is difficult to combine micro-evaluation with the macro-evaluation process. To effectively eliminate the subjective errors of the traditional analytic hierarchy process (AHP), a new modeling approach--the analytic hierarchy process and grey target theory (AHP-GTT) systematic model--is presented in this study to evaluate water quality in a certain watershed. A case study of applying the AHP-GTT systematic model to the evaluation and analysis of the water environment was conducted in the Yibin section of the Yangtze River, China. The micro-evaluation is based on defining the weights of indices of the water quality (IWQ) of each water cross-section, while the macro-evaluation is based on calculating the comprehensive indices of water environmental quality and analyzing the tendency of the water environment of each cross-section. The results indicated that the Baixi and Shuidongmen sections are seriously polluted areas, with the tendencies of becoming worse. Also, the key IWQs of these two cross-sections are 5-day biochemical oxygen demand and chemical oxygen demand of permanganate, respectively. [ABSTRACT FROM AUTHOR]

The article focuses on a research that aims to assess the baseflow of the Yangtze River in China during the 2006-extreme drought year. It states that daily baseflow discharges were examined using hydrograph analysis to differentiate groundwater discharge from the surface flow. Results show that Upper Yangtze River Stream (UYSR) has larger baseflow discharge than the Mid-Lower Yangtze River Stream (MLYRS) while human activities contribute 10 percent to baseflow discharge.

The article presents a study on the multifractal detrended fluctuation analysis of streamflow series of the Yangtze River in China. It states that the types of multifractality of streamflow series from Cuntan, Yichang, Hankou, and Datong stations were studied using shuffled streamflow series, in which the results indicate that the discharge series of the Yangtze River basin are non-stationary. It discusses the discharge series of the upper Yangtze River basin, which are characterized by short memory or anti-persistence. It also notes that the streamflow series of the lower Yangtze River basin are characterized by long memory or persistence. It highlights the scientific importance of the study in regional flood frequency analysis and water resource management in the Yangtze River basin.

The swimbladder of fishes is readily compressed by hydrostatic pressure with depth, causing changes in buoyancy. While modern fishes can regulate buoyancy by secreting gases from the blood into the swimbladder, primitive fishes, such as sturgeons, lack this secretion mechanism and rely entirely on air gulped at the surface to inflate the swimbladder. Therefore, sturgeons may experience changes in buoyancy that will affect their behavior at different depths. To test this prediction, we attached data loggers to seven free-ranging Chinese sturgeons Acipenser sinensis in the Yangtze River, China, to monitor their depth utilization, tail-beating activity, swim speed and body inclination. Two distinct, individual-specific, behavioral patterns were observed. Four fish swam at shallow depths (7–31 m), at speeds of 0.5–0.6 m s−1, with ascending and descending movements of 1.0–2.4 m in amplitude. They beat their tails continuously, indicating that their buoyancy was close to neutral with their inflated swimbladders. In addition, their occasional visits to the surface suggest that they gulped air to inflate their swimbladders. The other three fish spent most of their time (88–94%) on the river bottom at a depth of 106–122 m with minimum activity. They occasionally swam upwards at speeds of 0.6–0.8 m s−1 with intense tailbeats before gliding back passively to the bottom, in a manner similar to fishes that lack a swimbladder. Their bladders were probably collapsed by hydrostatic pressure, resulting in negative buoyancy. We conclude that Chinese sturgeons behave according to their buoyancy, which varies with depth due to hydrostatic compression of the swimbladder. [ABSTRACT FROM AUTHOR]

Field experiments in Europe have shown that Chinese cultivars of winter oilseed rape ( Brassica napus) are very susceptible to the pathogen Leptosphaeria maculans (cause of phoma stem canker). Climatic and agronomic conditions in China are suitable for L. maculans since the closely related but less damaging pathogen L. biglobosa occurs on the winter and spring oilseed rape crops there. Major gene resistance to L. maculans is not durable; when introduced into commercial oilseed rape cultivars it is rapidly rendered ineffective by changes in the pathogen population. The threat to Chinese oilseed rape production from L. maculans is illustrated by the way in which L. maculans has spread into other areas of the world where previously only L. biglobosa was present, such as Canada and Poland. Models were developed to describe the spread (in space and time) of L. maculans across Alberta province, Canada, based on survey data collected over a 15-year period. These models were used to estimate the potential spread of L. maculans across the Yangtze river oilseed rape growing areas of China and its associated costs. Short-term strategies to prevent occurrence of severe phoma stem canker epidemics in China include training of extension workers to recognise symptoms of the disease and use of PCR-based diagnostics to detect the pathogen on imported seed. Long-term strategies include the introduction of durable resistance to L. maculans into Chinese oilseed rape cultivars as a component of an integrated disease management programme. The costs of such strategies in relation to costs of a phoma stem canker epidemic are discussed. [ABSTRACT FROM AUTHOR]

1. The Yangtze floodplain (SE China) is characterized by a number of large shallow lakes, many of which have undergone eutrophication due to the intensification of agriculture and urban growth over recent decades. As monitoring data are limited and in order to determine lake baseline nutrient concentrations, 49 lakes were sampled, covering a total phosphorus (TP) gradient ( c. 30–550 μg L−1) to develop a diatom-based inference model. 2. There are three dominant diatom assemblages in these shallow lakes with a marked change in assemblage structure near the boundary between eutrophic and hypereutrophic nutrient levels (as indicated by their TP value). Canonical correspondence analysis indicated that TP was the most important and significant variable in explaining the diatom distributions, independently accounting for 9.5% variance of diatoms. 3. Forty-three lakes were used to generate a transfer function using weighted averaging (WA) with inverse deshrinking. This model had low predictive error (root mean squared error of prediction; RMSEPjack = 0.12) and a high coefficient of prediction ( R2jack = 0.82), comparable with regional TP models elsewhere. The good performance of this TP model may reflect the low abundance of benthic diatom species which are commonly regarded as the main error source in European shallow lake WA models. 4. The WA model was used to reconstruct the past-TP concentrations for Taibai Lake, a shallow hypereutrophic lake in Hubei province. The results showed that TP concentration varied slightly (43–62 μg L−1) prior to the 1920s, indicating an eutrophic state since the 1800s. A period of sustained eutrophication occurred after 1950, because of the development of agriculture, reflecting by maximum values of Aulacoseira alpigena and increased abundance of Cyclotella meneghiniana, C. atomus and Cyclostephanos dubius. The steep increase in nutrient concentration after 1970 was related to the overuse of chemical fertilizer and fish farming in the catchment. 5. The shift in fossil diatoms from epiphytic to planktonic forms in the lake sediment core during 1950–70 provides useful information on the transformation from macrophyte-dominated to alga-dominated states. It is plausible that the TP concentration of 80–110 μg L−1 observed in this study is the critical range for switching between the two stable states in the lake. 6. The regional diatom-TP model developed in this study allows, therefore, the possibility of reconstructing historical background nutrient concentrations in lakes. It will provide an indication of the onset and development of eutrophication at any site. This is particularly important for the many lakes in the Yangtze floodplain where information about historical changes in water quality is lacking. [ABSTRACT FROM AUTHOR]

The article talks about the characterization and fitness of the carbendazim-resistant strains of Fusarium graminearum or wheat scab. The authors mentioned that wheat scab caused by Fusarium graminearum Schwabe on the eastern coast of China after 30 years of application has been failed to be controlled by Carbendazim (MBC). They reported that the resistance to MBC has been said to be common in pathogen on the locality of the Yangtze River and on the eastern coast. The author also said that MBC isolates posses high competition and fitness in field conferred by a novel molecular mechanism.

Middle indica cultivars are planted in the middle to lower regions of the Yangtze River. Hybrid combinations with these cultivars have a high yield potential but the presence of late-transgressive-segregants limits the further exploitation of heterosis. To understand the genetic basis of the heading date in these middle maturing cultivars, we carried out a genetic analysis of 10 typical middle-season cultivars using a number of heading date isogenic lines under both long and short day conditions. The results showed that Teqing, 752, CDR22, Bo B, 9311 and II-32B carry two photoperiod sensitive genes E1 or Se- 1 and E3, and Teqing, 752 and CDR22 carry a dominant early-heading gene Ef-1 while Bo B, 9311 and II-32B carry a recessive late-heading gene ef-1. Based on the findings of the present and previous works on Guichao 2, Minghui 63, Nanjing 11 and Pei'ai64S, it was concluded that all of these middle indica cultivars carried the recessive allele hd2, which could inhibit the expression of E1 or Se-1, and they formed rational combinations of genotype for heading date during a long period of evolution. The effects of the different combinations of genotype for heading date on rice cultivation and extension were discussed, and genetic basis of broad adaptability of hybrid middle indica cultivars was analyzed. [ABSTRACT FROM AUTHOR]

The Dexing deposit is located in a NE-trending magmatic belt along the southeastern margin of the Yangtze Craton. It is the largest porphyry copper deposit in China, consisting of three porphyry copper orebodies of Zhushahong, Tongchang and Fujiawu from northwest to southeast. It contains 1168 Mt of ores with 0.5% Cu and 0.01% Mo. The Dexing deposit is hosted by Middle Jurassic granodiorite porphyries and pelitic schist of Proterozoic age. The Tongchang granodiorite porphyry has a medium K cal-alkaline series, with medium K2O content (1.94–2.07 wt%), and low K2O/(Na2O + K2O) (0.33–0.84) ratios. They have high large-ion lithophile elements, high light rare-earth elements, and low high-field-strength elements. The hydrothermal alteration at Tongchang is divided into four alteration mineral assemblages and related vein systems. They are early K-feldspar alteration and A vein; transitional (chlorite + illite) alteration and B vein; late phyllic (quartz + muscovite) alteration and D vein; and latest carbonate, sulfate and oxide alteration and hematite veins. Primary fluid inclusions in quartz from phyllic alteration assemblage include liquid-rich (type 1), vapor-rich (type 2) and halite-bearing ones (type 3). These provide trapping pressures of 20–400 ´ 105 Pa of fluids responsible for the formation of D veins. Igneous biotite from least altered granochiorite porphyry and hydrothermal muscovite in mineralized granodiorite porphyry possess δ18O and δD values of 4.6‰ and −87‰ for biotite and 7.1–8.9‰, −71 to −73‰ for muscovite. Stable isotopic composition of the hydrothermal water suggests a magmatic origin. The carbon and oxygen isotope for hydrothermal calcite are −4.8 to −6.2‰ and 6.8–18.8‰, respectively. The δ34S of pyrite in quartz vein ranges from −0.1 to 3‰, whereas δ34S for chalcopyrite in calcite veins ranges from 4 to 5‰. These are similar to the results of previous studies, and suggest a magmatic origin for sulfur. Results from alteration assemblages and vein system observation, as well as geochemical, fluid inclusion, stable isotope studies indicate that the involvement of hydrothermal fluids exsolved from a crystallizing melt are responsible for the formation of Tongchang porphyry Cu-Mo orebodies in Dexing porphyry deposit. [ABSTRACT FROM AUTHOR]

The article offers information on the climactic teleconnections of summer monsoon streamflow to the Three Gorges Dam (TGD) at the Yangtze River Basin in China. From the period of 1882 to 2003, the summer monsoon inflow was analyzed at Yichang hydrological station (YHS). Statistical analysis was utilized to create a probative model for summer streamflow, followed by linear correlation maps using three-month ahead climate fields to determine the regions that exhibit climactic influences with streamflow at Yichang. The analysis shows regions in the eastern India and western Pacific oceans influences the YHS streamflow. It is inferred that an accurate climactic prediction can provide guidance for water management in the Yangtze River Basin.

The Upper Yangtze region yields a Hirnantian (latest Ordovician) graptolite fauna that includes 41 species assigned to 13 genera. This fauna is particularly important for understanding the Late Ordovician mass extinction event because it is the most diverse known from this interval. In addition, it records the survival, well into the Hirnantian, of many taxa of the Dicranograptidae-Diplograptidae-Orthograptidae (DDO) fauna, which was previously regarded as having gone extinct at the beginning of the Hirnantian. Taxa exhibiting six different astogenetic patterns, including taxa with reclined stipes, scandent, biserial, full-periderm and‘archiretiolitid’ rhabdosome forms occur in the lowerNormalograptus extraordinarius-N. ojsuensisBiozone. In contrast, in the upperN. persculptusBiozone only four genera remain, all but one of which are Normalograptidae: scandent and biserial taxa with Pattern H astogeny. Normalograptids are the dominant form of the succeeding, lower Rhuddanian, faunas. The Yangtze faunas also document the early expansion of normalograptids coeval with the decline of the DDO fauna. Many previously identified species considered endemic to China have been synonymized; 24 of the 41 species recorded here have been recognized elsewhere. No new taxa are described. [ABSTRACT FROM AUTHOR]

The relationship between surface sediment diatoms and summer water quality was investigated at 49 lakes in the middle and lower reaches of the Yangtze River. Lakes ranging from oligomesotrophic to hypereutrophic were examined, providing an obvious nutrient gradient. With the shift from mesotrophic to eutrophic levels, diatom multi-ecotypes dominated by epiphytic and facultative planktonic taxa were replaced by nutrient-tolerant planktonic taxa, such asCyclotella meneghinianaSkvortzow,C. atomusHustedt,CyclostephanosRound, andStephanodiscusEhrenberg etc., reflecting the nutrient changes in the lake. The relationship between diatoms and summer water quality indices was explored further using numeric analysis. Canonical correspondence analysis (CCA) with forward selection and a Monte Carlo permutation test revealed that of all 25 summer water environmental variables, total phosphorus (TP), chlorophyll a (Chl a), Secchi depth (SD), dissolved inorganic phosphorus, Cl-, SO42-, Mg2+, CO32-, and water depth were significant variables (P<0.05) in explaining diatom distributions. Of these, TP, Chla, SD, and Cl-, were the most important variables. The result of the correlation analysis also showed that a significant correlation exists among these variables, implying that these indices are either interconnected or independent in explaining the diatom data. For phosphorus-limited sites, TP was the most significant variable affecting the diatoms, also affecting changes in Chla, SD, and iron concentrations. The independence of Chl a may be related to algal competition induced by lake eutrophication, resulting in the feedback to diatom community. In addition to TP, SD can be related to sediment disturbance by wave action and the growth of macrophytes in large shallow lakes. These relationships between diatom ecotypes and water quality provide the basis for a future quantitative reconstruction of historic lake nutrient evolution in the study area and will also provide a wealth of modern ecological knowledge that can be used to interpret fossil diatom records.(Managing editor:Ya-QinHAN) [ABSTRACT FROM AUTHOR]

In order to understand the distribution of dinoflagellate cysts, surface sediments were collected from 15 stations in Changjiang River Estuary from 122°E to 123.5°E and from 29°N to 32°N in four cruises from May 2002 to February 2003. In the present study, 38 different cyst morphotypes representing 21 genera and 6 groups were identified, while 1 type was not identified into genus level. Species number and cell density of dinoflagellate cysts ranged from 10 to 25 species and from 12 to 587 per gram of dry weight, respectively. There were no obvious differences in cyst composition and density among seasons. However, the highest cyst species number and density were recorded in summer and winter, respectively. Cysts of heterotrophic dinoflagellates, which held 55.7% of the overall cyst density averagely, dominated cyst assemblages. Cyst density and species number increased from the west to the east, from the north to the south within the study area. Cysts of toxic dinoflagellatesAlexandrium catenellaandAlexandrium tamarensecomplex distributed widely and were observed in almost all stations, with the maximum cell density of 81 per gram of dry weight. [ABSTRACT FROM AUTHOR]

To document patterns in diversity, altitudinal range and body size of freshwater fishes along an elevational gradient in the Yangtze River basin.The Yangtze River basin, China.We used published data to compile the distribution, altitudinal range and body size of freshwater fishes. Correlation, regression, clustering and graphical analyses were used to explore patterns in diversity, altitudinal range and body size of freshwater fishes in 100-m elevation zones from 0 to 5200 m.Species richness patterns across the elevational gradient for total, non-endemic and endemic fishes were different. The ratio of endemics to total richness peaked at mid elevation. Land area on a 500-m interval scale explained a significant amount of the variation in species richness. Species density displayed two peaks at mid-elevation zones. The cluster analysis revealed five distinct assemblages across the elevation gradient. The relationship between elevational range size and the midpoint of the elevational range revealed a triangular distribution. The frequency distribution of log maximum standard length data displayed an atypical right-skewed pattern. Intermediate body sizes occurred across the greatest range of elevation while small and large body sizes possessed only small elevational amplitudes. The size-elevation relationship between the two major families revealed a very strong pattern of body size constraint among the Cobitidae with no corresponding elevational constraint and a lot of body size and elevational diversification among the Cyprinidae.The data failed to support either Rapoport's rule or Bergmann's rule. [ABSTRACT FROM AUTHOR]