Taxonomic and Functional Differences between Microbial Communities in Qinghai Lake and Its Input Streams

PubMed Central

Ren, Ze; Wang, Fang; Qu, Xiaodong; Elser, James J.; Liu, Yang; Chu, Limin

2017-01-01

Understanding microbial communities in terms of taxon and function is essential to decipher the biogeochemical cycling in aquatic ecosystems. Lakes and their input streams are highly linked. However, the differences between microbial assemblages in streams and lakes are still unclear. In this study, we conducted an intensive field sampling of microbial communities from lake water and stream biofilms in the Qinghai Lake watershed, the largest lake in China. We determined bacterial communities using high-throughput 16S rRNA gene sequencing and predicted functional profiles using PICRUSt to determine the taxonomic and functional differences between microbial communities in stream biofilms and lake water. The results showed that stream biofilms and lake water harbored distinct microbial communities. The microbial communities were different taxonomically and functionally between stream and lake. Moreover, streams biofilms had a microbial network with higher connectivity and modularity than lake water. Functional beta diversity was strongly correlated with taxonomic beta diversity in both the stream and lake microbial communities. Lake microbial assemblages displayed greater predicted metabolic potentials of many metabolism pathways while the microbial assemblages in stream biofilms were more abundant in xenobiotic biodegradation and metabolism and lipid metabolism. Furthermore, lake microbial assemblages had stronger predicted metabolic potentials in amino acid metabolism, carbon fixation, and photosynthesis while stream microbial assemblages were higher in carbohydrate metabolism, oxidative phosphorylation, and nitrogen metabolism. This study adds to our knowledge of stream-lake linkages from the functional and taxonomic composition of microbial assemblages. PMID:29213266

Impact of a thermokarst lake on the soil hydrological properties in permafrost regions of the Qinghai-Tibet Plateau, China.

PubMed

Gao, Zeyong; Niu, Fujun; Wang, Yibo; Luo, Jing; Lin, Zhanju

2017-01-01

The formation of thermokarst lakes can degrade alpine meadow ecosystems through changes in soil water and heat properties, which might have an effect on the regional surface water and groundwater processes. In this study, a typical thermokarst lake was selected in the Qinghai-Tibet Plateau (QTP), and the ecological index (S L ) was used to divide the affected areas into extremely affected, severely affected, medium-affected, lightly affected, and non-affected areas, and soil hydrological properties, including saturated hydraulic conductivity and soil water-holding capacity, were investigated. The results showed that the formation of a thermokarst lake can lead to the degradation of alpine meadows, accompanied by a change in the soil physiochemical and hydrological properties. Specifically, the soil structure turned towards loose soil and the soil nutrients decreased from non-affected areas to severely affected areas, but the soil organic matter and available potassium increased slightly in the extremely affected areas. Soil saturated hydraulic conductivity showed a 1.7- to 4.1-fold increase in the lake-surrounding areas, and the highest value (401.9cmd -1 ) was detected in the severely affected area. Soil water-holding capacity decreased gradually during the transition from the non-affected areas to the severely affected areas, but it increased slightly in the extremely affected areas. The principal component analysis showed that the plant biomass was vital to the changes in soil hydrological properties. Thus, the vegetation might serve as a link between the thermokarst lake and soil hydrological properties. In this particular case, it was concluded that the thermokarst lake adversely affected the regional hydrological services in the alpine ecosystem. These results would be useful for describing appropriate hydraulic parameters with the purpose of modeling soil water transportation more accurately in the Qinghai-Tibet Plateau. Copyright © 2016 Elsevier B.V. All

Lake Qinghai sediment geochemistry linked to hydroclimate variability since the last glacial

NASA Astrophysics Data System (ADS)

Jin, Zhangdong; An, Zhisheng; Yu, Jimin; Li, Fuchun; Zhang, Fei

2015-08-01

Geochemistry of basin sediments from semi-arid regions is valuable to understand past hydroclimatic changes. Here, we investigate the links of sedimentary geochemistry (Rb, Sr, Ca/Zr, TOC, and %CaCO3), carbonate mineralogy and ostracod shell δ18O of Lake Qinghai, a basin proximal to major dust production centers at mid-latitudes of the Northern Hemisphere, to changes in depositional conditions and hydroclimate during the past 32 ka. Surface lacustrine sediments are characterized by low-Rb, high-Sr, low-Rb/Sr, high-%CaCO3 and high-Ca/Zr values, in contrast to the chemical compositions of eolian loess (high-Rb, low-Sr, high-Rb/Sr, low-%CaCO3, and low-Ca/Zr). A direct comparison of soluble Ca and Sr in two short cores with instrumental water discharge data suggests that lacustrine precipitates in Lake Qinghai are dominated by authigenic aragonite formed under Ca2+-limited water conditions, and that the accumulation rate of aragonite dominantly depends on solute fluxes into the lake during the rainy seasons (late May to September). Our high-resolution down-core records show that sediments during the last glacial (∼32-19.8 ka) had high-Rb, low-Sr, low-%CaCO3, and low-Ca/Zr, indicating eolian dust (loess) accumulation in a desiccated basin under dry glacial conditions, further supported by grain size and pollen results. This type of sedimentation was maintained during the last deglacial (∼19.8-11.5 ka), but interrupted by episodic lacustrine precipitates with high-Sr, high-%CaCO3, high-Ca/Zr, and low-Rb. At ∼11.5 ka, sedimentary Rb/Sr, Ca/Zr, %CaCO3 and TOC show dramatic and permanent changes, implying an abrupt shift in the atmospheric circulation at the onset of the Holocene in the Lake Qinghai region. Lacustrine precipitates have persisted throughout the Holocene with a maximum during the early to mid-Holocene (∼10.5-8.0 ka). Since ∼8.0 ka, the gradual and significant decreases in aragonite and Sr accumulations in tandem with increasing dust deposit and

Centennial blooming of anoxygenic phototrophic bacteria in Qinghai Lake linked to solar and monsoon activities during the last 18,000 years

NASA Astrophysics Data System (ADS)

Ji, Junfeng; Balsam, William; Shen, Ji; Wang, Man; Wang, Hongtao; Chen, Jun

2009-06-01

The productivity of anoxygenic phototrophic bacteria (APB) can be inferred in the sediments of Qinghai Lake from the changing abundance of bacteriophaeophytin a (Bph- a). Using diffuse reflectance spectroscopy (DRS), we identified Bph- a in Qinghai Lake sediments from the late glacial period through the Holocene with a resolution of one sample every 30-50 years. The Bph- a profile of Qinghai Lake demonstrates that in the last 18,000 years APB were only present between 4.2 and 14 ka BP, a period of high rainfall and high summer solar insolation. All the APB blooming events correspond to times of enhanced freshwater influx as revealed by percent redness, an indicator of the input of iron oxide minerals. Our data suggest that solar insolation sets the stage for APB blooms, which are then promoted by increased summer monsoon rainfall and nutrients resulting in the development of a chemocline in the lake. The blooming of APB in Qinghai Lake appears as discrete centennial-scale APB events likely linked to solar activities. Our results suggest the presence of solar-induced, century-long, intense summer monsoon episodes in the middle and early Holocene and the late glacial period.

Holocene moisture and East Asian summer monsoon evolution in the northeastern Tibetan Plateau recorded by Lake Qinghai and its environs: A review of conflicting proxies

NASA Astrophysics Data System (ADS)

Chen, Fahu; Wu, Duo; Chen, Jianhui; Zhou, Aifeng; Yu, Junqing; Shen, Ji; Wang, Sumin; Huang, Xiaozhong

2016-12-01

Climatic and environmental changes in the northeastern Tibetan Plateau are controlled by the Asian summer monsoon (ASM) and the westerlies, two key circulation components of the global climate system which directly affect a large human population and associated ecosystems in eastern Asia. During the past few decades, a series of Holocene palaeoclimatic records have been obtained from sediment cores from Lake Qinghai and from various other geological archives in the surrounding area of the northeastern Tibetan Plateau. However, because of uncertainties regarding the sediment chronologies and the climatic significance of the proxies used, the nature of Holocene climatic changes in the region remains unclear and even controversial. Here we review all major classes of the published data from drilled cores from Lake Qinghai, as well as other evidence from lakes and aeolian deposits from surrounding areas, in order to reconstruct changes in moisture patterns and possible summer monsoon evolution in the area during the Holocene. Combining the results of moisture and precipitation proxies such as vegetation history, pollen-based precipitation reconstruction, aeolian activity, lake water depth/lake level changes, salinity and sediment redness, we conclude that moisture and precipitation began to increase in the early Holocene, reached their maximum during the middle Holocene, and decreased during the late Holocene - similar to the pattern of the East Asian summer monsoon (EASM) in northern China. It is clear that the region experienced a relatively dry climate and weak EASM during the early Holocene, as indicated by relatively low tree pollen percentages and fluctuating pollen concentrations; generally low lake levels of Lake Qinghai and the adjacent Lake Hurleg and Lake Toson in the Qaidam Basin; and widely distributed aeolian sand deposition in the Lake Qinghai Basin and the nearby Gonghe Basin to the south, and in the eastern Qaidam Basin to the west. We argue that the

The role of clay minerals in the preservation of organic matter in sediments of Qinghai Lake, NW China

USGS Publications Warehouse

Yu, Bingsong; Dong, Hailiang; Jiang, Hongchen; Lv, Guo; Eberl, Dennis D.; Li, Shanying; Kim, Jinwook

2009-01-01

The role of saline lake sediments in preserving organic matter has long been recognized. In order to further understand the preservation mechanisms, the role of clay minerals was studied. Three sediment cores, 25, 57, and 500 cm long, were collected from Qinghai Lake, NW China, and dissected into multiple subsamples. Multiple techniques were employed, including density fractionation, X-ray diffraction, scanning and transmission electron microscopy (SEM and TEM), total organic carbon (TOC) and carbon compound analyses, and surface area determination. The sediments were oxic near the water-sediment interface, but became anoxic at depth. The clay mineral content was as much as 36.8%, consisting mostly of illite, chlorite, and halloysite. The TEM observations revealed that organic matter occurred primarily as organic matter-clay mineral aggregates. The TOC and clay mineral abundances are greatest in the mid-density fraction, with a positive correlation between the TOC and mineral surface area. The TOC of the bulk sediments ranges from 1 to 3% with the non-hydrocarbon fraction being predominant, followed by bitumen, saturated hydrocarbon, aromatic hydrocarbons, and chloroform-soluble bitumen. The bimodal distribution of carbon compounds of the saturated hydrocarbon fraction suggests that organic matter in the sediments was derived from two sources: terrestrial plants and microorganisms/algae. Depthrelated systematic changes in the distribution patterns of the carbon compounds suggest that the oxidizing conditions and microbial abundance near the water-sediment interface promote degradation of labile organic matter, probably in adsorbed form. The reducing conditions and small microbial biomass deeper in the sediments favor preservation of organic matter, because of the less labile nature of organic matter, probably occurring within clay mineral-organic matter aggregates that are inaccessible to microorganisms. These results have important implications for our

Alkenone temperature and salinity: An evaluation of long chain C37 alkenone in Lake Qinghai, China

NASA Astrophysics Data System (ADS)

Liu, W.; Liu, Z.; Fu, M.; An, Z.

2007-12-01

In recently years, the alkenone unsaturation index (Uk'37=C37:.2/(C37:2+ C37:3)) has been used to reconstructed paleo-temperature for lacustrine sediments. However, few studies have addressed whether the relative abundance of the C37:4 alkenone to the total C37 production (C37:4 percent) can reflect surface salinity changes in lake systems. Here we present the distribution of C37 long chain alkenone of modern lake sediments in Qinghai Lake, Qing-Tibet Plateau, to evaluate significance of abundance change of long chain C37 alkenone as an indicator of lake paleo-enviromental evolution. A group of surface sediments from different locations in the lake have been analyzed in this study. The results of long chain C37 alkenone from 28 surface sediments analyses shown relative abundance of C37:4 alkenone to total C37 production (C37:4 percent) change from 14.5 to 48.6 percent and the abundance of C37:4 alkenone is increasing with decreasing salinity of lake water. For the salinity lake in land, we suggested the relative abundance of C37:4 alkenone in lake sediments may be a indicator of paleo-silinity; We have also found that Uk'37 values are weakly correlated with salinity and C37:4 percent changes, implying that potential minor contributions of temperature and salinity effects to C37:4 percent and Uk'37 respectively cannot be excluded in this study. However, since these contributions are weak, we suggest that the C37:4 percent proxy can be used to reconstruct paleo-salinity changes at a regional scale, especially in lake systems, while Uk'37 remains as a powerful tool for reconstructions of paleo-temperature changes in the lake systems.

Hydrochemistry and controlling mechanism of lakes in permafrost regions along the Qinghai-Tibet Engineering Corridor, China

NASA Astrophysics Data System (ADS)

Gao, Zeyong; Lin, Zhanju; Niu, Fujun; Luo, Jing; Liu, Minghao; Yin, Guoan

2017-11-01

Lakes are the main water resource for migrating animals and herdsmen in permafrost regions along the Qinghai-Tibet Engineering Corridor (QTEC) and play a crucial role in regulating the balance between regional surface water and groundwater. Hydrochemical properties also affect the soil environment, ecological conditions, and hydrological cycle. In this study, 127 water samples were collected from lakes to analyze hydrochemistry characteristics. The results are discussed in the context of relationships between water chemistry and local conditions including climate, topography, and geology. The results showed that 43.3% of lakes are fresh, 19.7% are brackish, 18.9% are saline, 17.3% are brine, and only 0.8% are bitter. The dominant cation is Na+, followed by Mg2 +, Ca2 +, and K+. The dominant anion is Cl-, followed by SO42 - and HCO3- in the northern section of study region; whereas Ca2 +, Na+, and HCO3- are the dominant ions in the lakes of the southern section. The higher concentrations of carbonate in the southern lakes reflect contributions from groundwater discharge. In contrast, the higher concentrations of sodium, chloride, and sulfate in the northern section indicate that they are dominated by the interaction of evaporates. Additionally, cation exchange, precipitation, and dissolution have also modified the distribution of hydrochemical compositions. Thermokarst processes, in particular, have induced changes in the hydrochemistry of lake waters in the permafrost regions of the QTEC, in that the ion concentrations are closely related to ground ice content. In the context of persistent climatic warming and steadily increasing anthropogenic activities, the salinity of lakes along the QTEC is likely to increase in the future.

Monitoring the lake area changes of the Qinghai-Tibet Plateau using coarse-resolution time series remote sensing data

NASA Astrophysics Data System (ADS)

Ma, M.

2015-12-01

The Qinghai-Tibet Plateau (QTP) is the world's highest and largest plateau and is occasionally referred to as "the roof of the world". As the important "water tower", there are 1,091 lakes of more than 1.0 km2 in the QTP areas, which account for 49.4% of the total area of lakes in China. Some studies focus on the lake area changes of the QTP areas, which mainly use the middle-resolution remote sensing data (e.g. Landsat TM). In this study, the coarse-resolution time series remote sensing data, MODIS data at a spatial resolution of 250m, was used to monitor the lake area changes of the QTP areas during the last 15 years. The dataset is the MOD13Q1 and the Normal Difference Vegetation Index (NDVI) is used to identify the lake area when the NDVI is less than 0. The results show the obvious inner-annual changes of most of the lakes. Therefore the annually average and maximum lake areas are calculated based on the time series remote data, which can better quantify the change characteristics than the single scene of image data from the middle-resolution data. The results indicate that there are big spatial variances of the lake area changes in the QTB. The natural driving factors are analyzed for revealing the causes of changes.

Hydrological and solute budgets of Lake Qinghai, the largest lake on the Tibetan Plateau

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Zhangdong; You, Chen-Feng; Wang, Yi

2009-12-04

Water level and chemistry of Lake Qinghai are sensitive to climate changes and are important for paleoclimatic implications. An accurate understanding of hydrological and chemical budgets is crucial for quantifying geochemical proxies and carbon cycle. Published results of water budget are firstly reviewed in this paper. Chemical budget and residence time of major dissolved constituents in the lake are estimated using reliable water budget and newly obtained data for seasonal water chemistry. The results indicate that carbonate weathering is the most important riverine process, resulting in dominance of Ca 2+ and DIC for river waters and groundwater. Groundwater contribution tomore » major dissolved constituents is relatively small (4.2 ± 0.5%). Wet atmospheric deposition contributes annually 7.4–44.0% soluble flux to the lake, resulting from eolian dust throughout the seasons. Estimates of chemical budget further suggest that (1) the Buha-type water dominates the chemical components of the lake water, (2) Na +, Cl -, Mg 2+ , and K + in lake water are enriched owing to their conservative behaviors, and (3) precipitation of authigenic carbonates (low-Mg calcite, aragonite, and dolomite) transits quickly dissolved Ca 2+ into the bottom sediments of the lake, resulting in very low Ca 2+ in the lake water. Therefore, authigenic carbonates in the sediments hold potential information on the relative contribution of different solute inputs to the lake and the lake chemistry in the past.« less

Wild Bird Migration across the Qinghai-Tibetan Plateau: A Transmission Route for Highly Pathogenic H5N1

PubMed Central

Prosser, Diann J.; Cui, Peng; Takekawa, John Y.; Tang, Mingjie; Hou, Yuansheng; Collins, Bridget M.; Yan, Baoping; Hill, Nichola J.; Li, Tianxian; Li, Yongdong; Lei, Fumin; Guo, Shan; Xing, Zhi; He, Yubang; Zhou, Yuanchun; Douglas, David C.; Perry, William M.; Newman, Scott H.

2011-01-01

Background Qinghai Lake in central China has been at the center of debate on whether wild birds play a role in circulation of highly pathogenic avian influenza virus H5N1. In 2005, an unprecedented epizootic at Qinghai Lake killed more than 6000 migratory birds including over 3000 bar-headed geese (Anser indicus). H5N1 subsequently spread to Europe and Africa, and in following years has re-emerged in wild birds along the Central Asia flyway several times. Methodology/Principal Findings To better understand the potential involvement of wild birds in the spread of H5N1, we studied the movements of bar-headed geese marked with GPS satellite transmitters at Qinghai Lake in relation to virus outbreaks and disease risk factors. We discovered a previously undocumented migratory pathway between Qinghai Lake and the Lhasa Valley of Tibet where 93% of the 29 marked geese overwintered. From 2003–2009, sixteen outbreaks in poultry or wild birds were confirmed on the Qinghai-Tibet Plateau, and the majority were located within the migratory pathway of the geese. Spatial and temporal concordance between goose movements and three potential H5N1 virus sources (poultry farms, a captive bar-headed goose facility, and H5N1 outbreak locations) indicated ample opportunities existed for virus spillover and infection of migratory geese on the wintering grounds. Their potential as a vector of H5N1 was supported by rapid migration movements of some geese and genetic relatedness of H5N1 virus isolated from geese in Tibet and Qinghai Lake. Conclusions/Significance This is the first study to compare phylogenetics of the virus with spatial ecology of its host, and the combined results suggest that wild birds play a role in the spread of H5N1 in this region. However, the strength of the evidence would be improved with additional sequences from both poultry and wild birds on the Qinghai-Tibet Plateau where H5N1 has a clear stronghold. PMID:21408010

Wild bird migration across the Qinghai-Tibetan plateau: a transmission route for highly pathogenic H5N1.

PubMed

Prosser, Diann J; Cui, Peng; Takekawa, John Y; Tang, Mingjie; Hou, Yuansheng; Collins, Bridget M; Yan, Baoping; Hill, Nichola J; Li, Tianxian; Li, Yongdong; Lei, Fumin; Guo, Shan; Xing, Zhi; He, Yubang; Zhou, Yuanchun; Douglas, David C; Perry, William M; Newman, Scott H

2011-03-09

Qinghai Lake in central China has been at the center of debate on whether wild birds play a role in circulation of highly pathogenic avian influenza virus H5N1. In 2005, an unprecedented epizootic at Qinghai Lake killed more than 6000 migratory birds including over 3000 bar-headed geese (Anser indicus). H5N1 subsequently spread to Europe and Africa, and in following years has re-emerged in wild birds along the Central Asia flyway several times. To better understand the potential involvement of wild birds in the spread of H5N1, we studied the movements of bar-headed geese marked with GPS satellite transmitters at Qinghai Lake in relation to virus outbreaks and disease risk factors. We discovered a previously undocumented migratory pathway between Qinghai Lake and the Lhasa Valley of Tibet where 93% of the 29 marked geese overwintered. From 2003-2009, sixteen outbreaks in poultry or wild birds were confirmed on the Qinghai-Tibet Plateau, and the majority were located within the migratory pathway of the geese. Spatial and temporal concordance between goose movements and three potential H5N1 virus sources (poultry farms, a captive bar-headed goose facility, and H5N1 outbreak locations) indicated ample opportunities existed for virus spillover and infection of migratory geese on the wintering grounds. Their potential as a vector of H5N1 was supported by rapid migration movements of some geese and genetic relatedness of H5N1 virus isolated from geese in Tibet and Qinghai Lake. This is the first study to compare phylogenetics of the virus with spatial ecology of its host, and the combined results suggest that wild birds play a role in the spread of H5N1 in this region. However, the strength of the evidence would be improved with additional sequences from both poultry and wild birds on the Qinghai-Tibet Plateau where H5N1 has a clear stronghold.

[Mutation analysis of the PAH gene in children with phenylketonuria from the Qinghai area of China].

PubMed

He, Jiang; Wang, Hui-Zhen; Xu, Fa-Liang; Yang, Xi; Wang, Rui; Zou, Hong-Yun; Yu, Wu-Zhong

2015-11-01

To study the mutation characteristics of the phenylalanine hydroxylase (PAH) gene in children with phenylketonuria (PKU) from the Qinghai area of China, in order to provide basic information for genetic counseling and prenatal diagnosis. Mutations of the PAH gene were detected in the promoter and exons 1-13 and their flanking intronic sequences of PAH gene by PCR and DNA sequencing in 49 children with PKU and their parents from the Qinghai area of China. A total of 30 different mutations were detected in 80 out of 98 mutant alleles (82%), including 19 missense (63%), 5 nonsense (17%), 3 splice-site (10%) and 3 deletions (10%). Most mutations were detected in exons 3, 6, 7, 11 and intron 4 of PAH gene. The most frequent mutations were p.R243Q (19%), IVS4-1G>A (9%), p.Y356X (7%) and p.EX6-96A>G(5%). Two novel mutations p.N93fsX5 (c.279-282delCATC) and p.G171E (c.512G>A) were found. p.H64fsX9(c.190delC) was documented for the second time in Chinese PAH gene. The mutation spectrum of the gene PAH in the Qinghai population was similar to that in other populations in North China while significantly different from that in the populations from some provinces in southern China, Japan and Europe. The mutations of PAH gene in the Qinghai area of China demonstrate a unique diversity, complexity and specificity.

Climate change and tectonic activity during the early Pliocene Warm Period from the ostracod record at Lake Qinghai, northeastern Tibetan Plateau

NASA Astrophysics Data System (ADS)

Lu, Fengyan; An, Zhisheng; Chang, Hong; Dodson, John; Qiang, Xiaoke; Yan, Hong; Dong, Jibao; Song, Yougui; Fu, Chaofeng; Li, Xiangzhong

2017-05-01

The Early Pliocene Warm Period (EPWP, 5-3 Ma) is sometimes thought to be a useful analogue for a future warmer world, and thus the boundary conditions and drivers of climate in the EPWP may provide valuable lessons for understanding how a future warmer world might unfold. Lake Qinghai is located on the northeastern margin of the Tibetan Plateau (TP) and is affected by both Monsoon climate and Westerlies circulation. It is sensitive to the climate drivers of these systems. Its sediments, accumulated over the Cenozoic period, are a rich source of information for climate, tectonics and environmental changes of the period. We present a high-resolution ostracod record from a Lake Qinghai sediment core with a record of the period 5.10-2.60 Ma, thus covering the EPWP. Ostracods appear at 4.63 Ma and are most abundant until 3.58 Ma, while a body of water was present at the core site. This suggests a phase of humid climate and an intensified Asian Summer Monsoon (ASM), which is consistent with a warmer and wetter climate in the early Pliocene. Within this period the ostracod record shows some variabilities in lake level with deeper periods suggesting more intense ASM compared to those with shallower water. The disappearance of ostracods at 3.58 Ma may provide evidence for the uplift of Qinghai Nanshan (south of Qinghai Lake) since this is when the ASM intensified.

Land Use and Land Cover Change in the Qinghai Lake Region of the Tibetan Plateau and Its Impact on Ecosystem Services

PubMed Central

Gong, Jian; Yang, Jianxin; Tang, Wenwu

2017-01-01

Exploration of land use and land cover change (LULCC) and its impacts on ecosystem services in Tibetan plateau is valuable for landscape and environmental conservation. In this study, we conduct spatial analysis on empirical land use and land cover data in the Qinghai Lake region for 1990, 2000, and 2010 and simulate land cover patterns for 2020. We then evaluate the impacts of LULCC on ecosystem service value (ESV), and analyze the sensitivity of ESV to LULCC to identify the ecologically sensitive area. Our results indicate that, from 1990 to 2010, the area of forest and grassland increased while the area of unused land decreased. Simulation results suggest that the area of grassland and forest will continue to increase and the area of cropland and unused land will decrease for 2010–2020. The ESV in the study area increased from 694.50 billion Yuan in 1990 to 714.28 billion Yuan in 2000, and to 696.72 billion Yuan in 2020. Hydrology regulation and waste treatment are the top two ecosystem services in this region. The towns surrounding the Qinghai Lake have high ESVs, especially in the north of the Qinghai Lake. The towns with high ESV sensitivity to LULCC are located in the northwest, while the towns in the north of the Qinghai Lake experienced substantial increase in sensitivity index from 2000–2010 to 2010–2020, especially for three regulation services and aesthetic landscape provision services. PMID:28754029

Land Use and Land Cover Change in the Qinghai Lake Region of the Tibetan Plateau and Its Impact on Ecosystem Services.

PubMed

Gong, Jian; Li, Jingye; Yang, Jianxin; Li, Shicheng; Tang, Wenwu

2017-07-21

Exploration of land use and land cover change (LULCC) and its impacts on ecosystem services in Tibetan plateau is valuable for landscape and environmental conservation. In this study, we conduct spatial analysis on empirical land use and land cover data in the Qinghai Lake region for 1990, 2000, and 2010 and simulate land cover patterns for 2020. We then evaluate the impacts of LULCC on ecosystem service value (ESV), and analyze the sensitivity of ESV to LULCC to identify the ecologically sensitive area. Our results indicate that, from 1990 to 2010, the area of forest and grassland increased while the area of unused land decreased. Simulation results suggest that the area of grassland and forest will continue to increase and the area of cropland and unused land will decrease for 2010-2020. The ESV in the study area increased from 694.50 billion Yuan in 1990 to 714.28 billion Yuan in 2000, and to 696.72 billion Yuan in 2020. Hydrology regulation and waste treatment are the top two ecosystem services in this region. The towns surrounding the Qinghai Lake have high ESVs, especially in the north of the Qinghai Lake. The towns with high ESV sensitivity to LULCC are located in the northwest, while the towns in the north of the Qinghai Lake experienced substantial increase in sensitivity index from 2000-2010 to 2010-2020, especially for three regulation services and aesthetic landscape provision services.

Spatial and temporal variations of Rb/Sr ratios of the bulk surface sediments in Lake Qinghai

PubMed Central

2010-01-01

The Rb/Sr ratios of lake sediments have been suggested as indicators of weathering intensity by increasing work. However, the geochemistry of Rb/Sr ratios of lake sediments is variable between different lakes. In this study, we investigated the spatial and temporal patterns of Rb/Sr ratios, as well as those of other major elements in surface sediments of Lake Qinghai. We find that the spatial pattern of Rb/Sr ratios of the bulk sediments correlates well with that of the mass accumulation rate, and those of the terrigenous fractions, e.g., SiO2, Ti, and Fe. The temporal variations of Rb/Sr ratios also synchronize with those of SiO2, Ti, and Fe of each individual core. These suggest that Rb/Sr ratios of the surface sediments are closely related to terrigenous input from the catchment. Two out of eight cores show similar trends between Rb/Sr ratios and precipitation indices on decadal scales; however, the other cores do not show such relationship. The result of this study suggests that physical weathering and chemical weathering in Lake Qinghai catchment have opposite influence on Rb/Sr ratios of the bulk sediments, and they compete in dominating the Rb/Sr ratios of lake sediments on different spatial and temporal scales. Therefore, it is necessary to study the geochemistry of Rb/Sr ratio of lake sediments (especially that on short term timescales) particularly before it is used as an indicator of weathering intensity of the catchment. PMID:20615264

Surveillance of Echinococcus isolates from Qinghai, China.

PubMed

Ma, Junying; Wang, Hu; Lin, Gonghua; Zhao, Fang; Li, Chao; Zhang, Tongzuo; Ma, Xiao; Zhang, Yongguo; Hou, Zhibin; Cai, Huixia; Liu, Peiyun; Wang, Yongshun

2015-01-15

Echinococcosis is highly endemic over large parts of the Qinghai-Tibet Plateau (QTP), China. Based on a large number of samples, we present data on the current presence, host distribution, and genetic diversity of Echinococcus in the Qinghai Province, located in the northeastern corner of the QTP and constituting >25% of the area of the plateau. We used 521 samples (including 451 newly collected samples and 70 samples from our previous study) from humans, yaks, sheep, goats, dogs, fox, plateau pikas, and voles in 36 counties, and genotyped them using the mitochondrial DNA marker cytochrome oxidase subunit I (cox1) gene and the maximum parsimony and Bayesian reconstruction methods. Based on the 792 bp sequence matrix, we recorded 177 variable sites; 157 were parsimony-informative. A total of 105 haplotypes (H1-H105) were detected, of which H1-H15 and H90-H104, H16-H17, H18-H89, and H105 belonged to Echinococcus shiquicus, Echinococcus multilocularis, Echinococcus granulosus, and Echinococcus canadensis, respectively. Our results showed that, (i) the Qinghai Province was under a high burden of Echinococcus epidemiology; (ii) E. granulosus was the main echinococcosis threat to the local people, and the followed is E. multilocularis; (iii) there are a considerable number of haplotypes shared by domestic animals (sheep, yaks, and dogs) and humans, demonstrating the close relationship between human and domestic animals epidemiology; (iv) the threat of E. shiquicus on humans and livestock can be mostly ignored, while the infection risk of E. canadensis echinococcosis should not be neglected. Copyright © 2014 Elsevier B.V. All rights reserved.

Mosquitoes and Mosquito-Borne Arboviruses in the Qinghai-Tibet Plateau—Focused on the Qinghai Area, China

PubMed Central

Li, Wen-Juan; Wang, Jing-Lin; Li, Ming-Hua; Fu, Shi-Hong; Wang, Huan-Yu; Wang, Zhi-Yu; Jiang, Shuang-Ying; Wang, Xue-Wen; Guo, Peng; Zhao, Sheng-Cang; Shi, Yan; Lu, Nan-Nan; Nasci, Roger S.; Tang, Qing; Liang, Guo-Dong

2010-01-01

An investigation was conducted to identify the distribution of mosquitoes and mosquito-borne arboviruses in the Qinghai-Tibet Plateau, China from July to August in 2007. A total of 8,147 mosquitoes representing six species from three genera (Aedes, Culex, and Anopheles) were collected in three locations (Geermu city, altitude of 2,780 m; Xining city, 2,200 m; Minhe county, 1,700 m). Six virus isolates were obtained including Tahyna virus (TAHV), Liaoning virus, and Culex pipiens pallens Densovirus. A serosurvey showed immunoglobulin G antibodies by immunofluorescence assay (IFA) against TAHV in residents of all three locations. The IFA-positive human samples were confirmed by 90% plaque-reduction neutralization tests (PRNT90) against TAHV with titers ranging from 1:20 to 1:10,240. In addition, TAHV seropositive cows, sheep, and swine were found in these locations. This investigation represents the first isolation of TAHV from Ae. (Och.) detritus and the first evidence of TAHV infection in residents and livestock in the Qinghai-Tibet Plateau. PMID:20348523

Benthic Algal Community Structures and Their Response to Geographic Distance and Environmental Variables in the Qinghai-Tibetan Lakes With Different Salinity

PubMed Central

Yang, Jian; Jiang, Hongchen; Liu, Wen; Wang, Beichen

2018-01-01

Uncovering the limiting factors for benthic algal distributions in lakes is of great importance to understanding of their role in global carbon cycling. However, limited is known about the benthic algal community distribution and how they are influenced by geographic distance and environmental variables in alpine lakes. Here, we investigated the benthic algal community compositions in the surface sediments of six lakes on the Qinghai-Tibetan Plateau (QTP), China (salinity ranging from 0.8 to 365.6 g/L; pairwise geographic distance among the studied lakes ranging 8–514 km) employing an integrated approach including Illumina-Miseq sequencing and environmental geochemistry. The results showed that the algal communities of the studied samples were mainly composed of orders of Bacillariales, Ceramiales, Naviculales, Oscillatoriales, Spirulinales, Synechococcales, and Vaucheriales. The benthic algal community compositions in these QTP lakes were significantly (p < 0.05) correlated with many environmental (e.g., dissolved inorganic and organic carbon, illumination intensity, total nitrogen and phosphorus, turbidity and water temperature) and spatial factors, and salinity did not show significant influence on the benthic algal community structures in the studied lakes. Furthermore, geographic distance showed strong, significant correlation (r = 0.578, p < 0.001) with the benthic algal community compositions among the studied lakes, suggesting that spatial factors may play important roles in influencing the benthic algal distribution. These results expand our current knowledge on the influencing factors for the distributions of benthic alga in alpine lakes. PMID:29636745

Mapping risk of plague in Qinghai-Tibetan Plateau, China.

PubMed

Qian, Quan; Zhao, Jian; Fang, Liqun; Zhou, Hang; Zhang, Wenyi; Wei, Lan; Yang, Hong; Yin, Wenwu; Cao, Wuchun; Li, Qun

2014-07-10

Qinghai-Tibetan Plateau of China is known to be the plague endemic region where marmot (Marmota himalayana) is the primary host. Human plague cases are relatively low incidence but high mortality, which presents unique surveillance and public health challenges, because early detection through surveillance may not always be feasible and infrequent clinical cases may be misdiagnosed. Based on plague surveillance data and environmental variables, Maxent was applied to model the presence probability of plague host. 75% occurrence points were randomly selected for training model, and the rest 25% points were used for model test and validation. Maxent model performance was measured as test gain and test AUC. The optimal probability cut-off value was chosen by maximizing training sensitivity and specificity simultaneously. We used field surveillance data in an ecological niche modeling (ENM) framework to depict spatial distribution of natural foci of plague in Qinghai-Tibetan Plateau. Most human-inhabited areas at risk of exposure to enzootic plague are distributed in the east and south of the Plateau. Elevation, temperature of land surface and normalized difference vegetation index play a large part in determining the distribution of the enzootic plague. This study provided a more detailed view of spatial pattern of enzootic plague and human-inhabited areas at risk of plague. The maps could help public health authorities decide where to perform plague surveillance and take preventive measures in Qinghai-Tibetan Plateau.

MLVA and MLST typing of Brucella from Qinghai, China.

PubMed

Ma, Jun-Ying; Wang, Hu; Zhang, Xue-Fei; Xu, Li-Qing; Hu, Gui-Ying; Jiang, Hai; Zhao, Fang; Zhao, Hong-Yan; Piao, Dong-Ri; Qin, Yu-Min; Cui, Bu-Yun; Lin, Gong-Hua

2016-04-13

The Qinghai-Tibet Plateau (QTP) of China is an extensive pastoral and semi-pastoral area, and because of poverty and bad hygiene conditions, Brucella is highly prevalent in this region. In order to adequately prevent this disease in the QTP region it is important to determine the identity of Brucella species that caused the infection. A total of 65 Brucella isolates were obtained from human, livestock and wild animals in Qinghai, a Chinese province in east of the QTP. Two molecular typing methods, MLVA (multi-locus variable-number tandem-repeat analysis) and MLST (multi locus sequence typing) were used to identify the species and genotypes of these isolates. Both MLVA and MLST typing methods classified the 65 isolates into three species, B. melitensis, B. abortus and B. suis, which included 60, 4 and 1 isolates respectively. The MLVA method uniquely detected 34 (Bm01 ~ Bm34), 3 (Ba01 ~ Ba03), and 1 (Bs01) MLVA-16 genotypes for B. melitensis, B. abortus and B. suis, respectively. However, none of these genotypes exactly matched any of the genotypes in the Brucella2012 MLVA database. The MLST method identified five known ST types: ST7 and ST8 (B. melitensis), ST2 and ST5 (B. abortus), and ST14 (B. suis). We also detected a strain with a mutant type (3-2-3-2-?-5-3-8-2) of ST8 (3-2-3-2-1-5-3-8-2). Extensive genotype-sharing events could be observed among isolates from different host species. There were at least three Brucella (B. melitensis, B. abortus and B. suis) species in Qinghai, of which B. melitensis was the predominant species in the area examined. The Brucella population in Qinghai was very different from other regions of the world, possibly owing to the unique geographical characteristics such as extremely high altitude in QTP. There were extensive genotype-sharing events between isolates obtained from humans and other animals. Yaks, sheep and blue sheep were important zoonotic reservoirs of brucellosis causing species found in humans.

Influence of long-range atmospheric transportation (LRAT) on mono-to octa-chlorinated PCDD/Fs levels and distributions in soil around Qinghai Lake, China.

PubMed

Han, Ying; Liu, Wenbin; Hansen, Hans Chr Bruun; Chen, Xuebin; Liao, Xiao; Li, Haifeng; Wang, Mengjing; Yan, Nan

2016-08-01

Long-range atmospheric transportation (LRAT) of persistent organic pollutants followed by their deposition in cold, arid regions is of wide concern. This problem occurs at Qinghai Lake in the northeastern Tibetan Plateau, a sparsely populated area with extreme weather conditions and little current or historical anthropogenic pollution. The concentrations and distribution patterns of the mono-to octa-chlorinated dibenzo-p-dioxin and dibenzofuran (PCDD/F) congeners in surface soil samples collected from around Qinghai Lake were quantified. Concentration differences between low-(mono-to tri-) chlorinated PCDD/Fs and high-(tetra-to octa-) chlorinated PCDD/Fs were measured. High PCDD/F levels were detected, with total concentrations of 15,108 ± 6323 pg/g for the 27 PCDD/F congeners and 15,104 ± 6324 pg/g for the low-chlorinated PCDD/Fs. The concentrations of 17 2,3,7,8-substituted PCDD/Fs were only 3.1 ± 4.4 pg/g and the corresponding international toxicity equivalency (I-TEQ) was 0.11 ± 0.22 pg I-TEQ/g. Given their higher vapor pressures and lower boiling points, low-chlorinated PCDD/Fs, were predominantly gaseous, whereas high-chlorinated PCDD/Fs were predominantly solid, indicating that there is a higher potential for long-range transport of low-chlorinated PCDD/Fs. Overall, because of their high LRAT potential, low-chlorinated PCDD/Fs may pose a greater risk to local ecosystems in cold, remote areas than high-chlorinated PCDD/Fs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Iodine isotopes (129I and 127I) in the hydrosphere of Qinghai-Tibet region and South China Sea.

PubMed

Yi, Peng; Chen, Xuegao; Wang, Zixia; Aldahan, Ala; Hou, Xiaolin; Yu, Zhongbo

2018-06-14

The radioactive isotope 129 I, with a half-life of 1.57 × 10 7 years, is widely used as a tracer to assess nuclear safety, to track environmental and geological events and to figure out the details of the stable iodine geochemical cycle. This work investigated the 129 I and 127 I distribution in water samples collected from the terrestrial (rivers, lakes and springs) and marine water systems (estuary and sea) in China. The measured 129 I concentrations of (1-51) × 10 6 atoms/L and 129 I/ 127 I ratios of (0.03-21) × 10 -10 shows the variability of 129 I level in the water systems. The local permafrost and seasonal frozen environment play a key role in groundwater recharge in the Qinghai-Tibet region, which is reflected in the 129 I distribution in surface water. The depth distribution of 129 I in the water column of the South China Sea reflects the effluence of different currents. The results also indicate that the hydrosphere of China contains one to three orders of magnitude less 129 I compared to those reported in Europe. Despite the large distance, the European nuclear fuel reprocessing facilities represent the major source of 129 I in the hydrosphere of China through atmospheric transport. The contribution of the Fukushima nuclear accident to 129 I levels in the hydrosphere of China was negligible. Copyright © 2018 Elsevier Ltd. All rights reserved.

Prevalence, Associated Risk Factors, and Phylogenetic Analysis of Toxocara vitulorum Infection in Yaks on the Qinghai Tibetan Plateau, China

PubMed Central

Li, Kun; Lan, Yanfang; Luo, Houqiang; Zhang, Hui; Liu, Dongyu; Zhang, Lihong; Gui, Rui; Wang, Lei; Shahzad, Muhammad; Sizhu, Suolang; Li, Jiakui; Chamba, Yangzom

2016-01-01

Toxocara vitulorum has been rarely reported in yaks at high altitudes and remote areas of Sichuan Province of Tibetan Plateau of China. The current study was designed to investigate the prevalence, associated risk factors, and phylogenetic characteristics of T. vitulorum in yak calves on the Qinghai Tibetan plateau. Fecal samples were collected from 891 yak calves and were examined for the presence of T. vitulorum eggs by the McMaster technique. A multivariable logistic regression model was employed to explore variables potentially associated with exposure to T. vitulorum infection. T. vitulorum specimens were collected from the feces of yaks in Hongyuan of Sichuan Province, China. DNA was extracted from ascaris. After PCR amplification, the sequencing of ND1 gene was carried out and phylogenetic analyses was performed by MEGA 6.0 software. The results showed that 64 (20.1%; 95% CI 15.8–24.9%), 75 (17.2; 13.8–21.1), 29 (40.9; 29.3–53.2), and 5 (7.6; 2.5–16.8) yak calves were detected out to excrete T. vitulorum eggs in yak calve feces in Qinghai, Tibet, Sichuan, and Gansu, respectively. The present study revealed that high infection and mortality by T. vitulorum is wildly spread on the Qinghai Tibetan plateau, China by fecal examination. Geographical origin, ages, and fecal consistencies are the risk factors associated with T. vitulorum prevalence by logistic regression analysis. Molecular detection and phylogenetic analysis of ND1 gene of T. vitulorum indicated that T. vitulorum in the yak calves on the Qinghai Tibetan plateau are homologous to preveiously studies reported. PMID:27853122

Summer moisture changes in the Lake Qinghai area on the northeastern Tibetan Plateau recorded from a meadow section over the past 8400 yrs

NASA Astrophysics Data System (ADS)

Li, Xiangzhong; Liu, Xiangjun; He, Yuxin; Liu, Weiguo; Zhou, Xin; Wang, Zheng

2018-02-01

Holocene climatic and environmental changes on the northeastern Tibetan Plateau (TP) have been widely discussed based on the climatic records from sedimentary cores. However, differences in the reconstructed climatic history from various studies in this region still exist, probably due to influence of climatic proxies from multiple factors and the chronological uncertainties in lacustrine sediments. Here we present records of terrestrial plant δ13C, soil color and total organic carbon content over the past 8400 years from a well-dated meadow section on the northeastern TP. The terrestrial plant δ13C value serves as a good summer precipitation/moisture indicator in the studied region. Soil color property and TOC content are also able to disentangle the moisture evolution history. All the data show much wet climates at 8400-7400 cal yr BP, dry climates at 7400-6000 cal yr BP and then wet conditions with fluctuation at 6000-3200 cal yr BP. Late Holocene moisture appears to be comparable with moist conditions from 6000 to 3200 cal yr BP. By further comparing the climatic variations in the Lake Qinghai area with records of the reconstructed summer temperature and the Asian Monsoon precipitation, we believe that the pattern of moisture/precipitation evolution in the Lake Qinghai area was not completely consistent with regions around Lake Qinghai, probably due to complicated interaction between the East Asian Summer Monsoon and the Indian Summer Monsoon.

Long-Term Remote Monitoring of Three Typical Lake Area Variations in the Northwest China Over the Past 40 Years

NASA Astrophysics Data System (ADS)

Liu, Y.; Lu, Y.; Li, Y.; Yue, H.

2018-04-01

water resources management and sustainable development strategy, but also provide reference for assessing the impact of climate change and human activities. This paper selects three inland lakes in Northwest China, using Landsat MSS/TM/ETM+/OLI data from 1970 to 2015, Normalized Difference Water Index (NDWI) and Modified Normalized Difference Water Index (MNDWI) were used to extract lake area and analysed the dynamic trends. Meteorological station rainfall, evaporation and other meteorological data of the lakes were used to analyse reasons for the area change. The results showed that area of Hongjiannao Lake in the past 40 a was reduced, the groundwater impoundment and underground coal mining are the main cause of area reduction; the area of Bosten Lake in recent 40 a showed a decreasing trend after the first increase, the area was mainly affected by the surface runoff and snowmelt; the area of Qinghai Lake in the past 40 a shows a trend of decreasing first and then increasing, the change of its area is mainly affected by regional precipitation and the inflow.

Soil water dynamics and evapotranspiration in alpine ecosystems in the NE of Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Li, Xiao-Yan; Zhang, Si-Yi; Ma, Yu-Jun

2015-04-01

Interactions between surface energy flux, evapotranspiration and soil water were poorly understood in the alpine ecosystems in the Qinghai-Tibet Plateau, which is a sensitive and vulnerable region to global climate change. For the first time, we continuously measured surface energy flux and soil water content (SWC) and estimated ET using bowen ratio energy balance method in the Qinghai Lake watershed, located in the northeast of Qinghai-Tibet Plateau between 2012 and 2013. The three ecosystems were Kobresia meadow (KMd.), Potentilla fruticosa shrub (PFSh.) and Achnatherum splendens steppe (ASSt.). Results indicated that there was a good negative correlation between ecosystem Bowen ratios and SWC in the growing season for the three ecosystems. Annual ET at KMd. and PFSh. was 16% and 3% less than local annual precipitation, while that at ASSt. was 26% larger than annual precipitation. Average annual ET was 507.9, 493.2 and 413.7 mm at PFSh., KMd. and ASSt., respectively. Fluctuations of daily ET at alpine ecosystems were primarily controlled by solar radiation, especially in the growing season, whereas, at ASSt. where precipitation and SWC was limited, ET was also controlled by water supply.

Late Pleistocene paleoclimatic history documented by an oxygen isotope record from carbonate sediments in Qarhan Salt Lake, NE Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Fan, QiShun; Ma, HaiZhou; Wei, HaiCheng; Shan, FaShou; An, FuYuan; Xu, LiMing; Madsen, David B.

2014-05-01

Late Pleistocene paleoclimatic variability on the northeastern Qinghai-Tibetan Plateau (NE QTP) was reconstructed using a chronology based on AMS 14C and 230Th dating results and a stable oxygen isotopic record. These are derived from lake carbonates in a 102-m-long Qarhan sediment core (ISL1A) collected from the eastern Qaidam Basin. Previous research indicates that the δ18O values of lacustrine carbonates are mainly controlled by the isotopic composition of lake water, which in turn is a function of regional P/E balance and the proportion of precipitation that is monsoon-derived on the NE QTP. Modern isotopic observations indicate that the δ18O values of lake carbonates in hyper-arid Qaidam Basin are more positive during the warm and wet period. Due to strong evaporation and continental effect in this basin, the positive δ18O values in the arid region indicate drier climatic conditions. Based on this interpretation and the δ18O record of fine-grained lake carbonates and dating results in ISL1A, the results imply that drier climatic conditions in the Qarhan region occurred in three intervals, around 90-80 ka, 52-38 ka and 10-9 ka, which could correspond to late MIS 5, middle MIS 3 and early Holocene, respectively. These three phases were almost coincided with low lake level periods of Gahai, Toson and Qinghai Lakes (to the east of Qarhan Lake) influenced by ASM on the orbital timescales. Meanwhile, there was an episode of relatively high δ18O value during late MIS 3, suggesting that relatively dry climatic condition in this period, rather than “a uniform Qarhan mega-paleolake” spanning the ˜44 to 22 ka period. These results insight into the understanding of “the Greatest Lake Period” on the QTP.

Olfactory and visual responses of the long-legged chafer hoplia spectabilis medvedev (Coleoptera: Scarabaeidae) in Qinghai province, China

USDA-ARS?s Scientific Manuscript database

The long-legged chafer, Hoplia spectabilis Medvedev (Coleoptera: Scarabaeidae), has recently been recorded in outbreak numbers in pastureland of Qinghai province, China. It is causing significant damage to several species of woody shrubs, especially Hippophae neurocarpa Liu and Ho (Elaeagnaceae), D...

Salinity shapes microbial diversity and community structure in surface sediments of the Qinghai-Tibetan Lakes.

PubMed

Yang, Jian; Ma, Li'an; Jiang, Hongchen; Wu, Geng; Dong, Hailiang

2016-04-26

Investigating microbial response to environmental variables is of great importance for understanding of microbial acclimatization and evolution in natural environments. However, little is known about how microbial communities responded to environmental factors (e.g. salinity, geographic distance) in lake surface sediments of the Qinghai-Tibetan Plateau (QTP). In this study, microbial diversity and community structure in the surface sediments of nine lakes on the QTP were investigated by using the Illumina Miseq sequencing technique and the resulting microbial data were statistically analyzed in combination with environmental variables. The results showed total microbial community of the studied lakes was significantly correlated (r = 0.631, P < 0.001) with lake salinity instead of geographic distance. This suggests that lake salinity is more important than geographic distance in shaping the microbial diversity and community structure in the studied samples. In addition, the abundant and rare taxa (OTUs with relative abundance higher than 1% and lower than 0.01% within one sample, respectively) were significantly (P < 0.05) correlated (r = 0.427 and 0.783, respectively) with salinity, suggesting rare taxa might be more sensitive to salinity than their abundant counterparts, thus cautions should be taken in future when evaluating microbial response (abundant vs. rare sub-communities) to environmental conditions.

Molecular characterization of Cryptosporidium from animal sources in Qinghai province of China.

PubMed

Karanis, Panagiotis; Plutzer, Judit; Halim, Norhaliza Abdul; Igori, Khatanbaatar; Nagasawa, Hideyuki; Ongerth, Jerry; Liqing, Ma

2007-11-01

The presence of Cryptosporidium oocysts in 20 zoo animals of the Xining Zoo, 16 farm yaks and 42 farm goats in Qinghai province, China was investigated by an immunofluorescence test (IFT). The species and/or genotypes were determined by nested polymerase chain reaction (PCR) and sequence analysis of a fragment of the small subunit (SSU) rRNA gene. Cryptosporidium oocysts were found in 16 zoo animals, 2 yaks, and 15 goats by IFT. The IFT positive samples were further investigated by PCR, and 16 of them were found to be positive by that method also. Sequence analysis of the PCR products derived from Cryptosporidium oocysts from Black leopard (Panthera pardus), Heijing He (Grus nigricollis), Barbary sheep (Ammotragus lervia), Takin (Budorcas taxicolor), Lesser panda (Ailurus fulgens), and White-eared pheasant (Crossoptilon crossoptilon) fecal samples matched that of Cryptosporidium parvum mouse genotype. Sequence analyses of other PCR products were consistent with cervine genotype Cryptosporidium from Ibex (Capra ibex), a novel Cryptosporidium genotype from a wild yak (Bos mutus), C. bovis-like genotype from one goat sample and also a novel Cryptosporidium genotype from one other separate goat sample. The present work reports the first data on Cryptosporidium infections in animals from the Qinghai province of mountainous central western China and the first findings of the 'cervine' genotype in Capra ibex, C. bovis-like genotype and the new Cryptosporidium spp. in farm goat and in wild yak.

The aliphatic hydrocarbon distributions of terrestrial plants around an alpine lake: a pilot study from Lake Ximencuo, Eastern Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Pu, Yang; Jia, Jihong; Cao, Jicheng

2017-12-01

As part of an investigation of the sources of aliphatic hydrocarbons to the sediments of alpine Lake Ximencuo, leaves of the eight dominant vascular plants were collected and their hydrocarbon contents were analyzed. A series of unsaturated aliphatic hydrocarbons were identified in the plant leaves; in particular, Festuca sp. contain a series of n-alkadienes that have rarely been reported in previous studies. The comparison of n-alkane proxies (ACL 27-33, ACL T, P aq, and CPI) and δ13Corg among plant leaves, surface soils, and lake sediments suggests that organic proxies have been altered to varying degrees during the transport and burial process of organic materials. It is believed that microbial reworking and source changes have great impacts on organic proxies in the alpine lake system. In addition, the cluster analysis for plant leaves depending on n-alkane compositions and the ACL T proxy generates similar results. Accordingly, we postulate that the average chain length of plant waxes might be a potential indicator of plant classification in regions such as the Qinghai-Tibet Plateau.

Concentrating Solar Power Projects - Qinghai Gonghe 50 MW CSP Plant |

Science.gov Websites

Concentrating Solar Power | NREL Qinghai Gonghe 50 MW CSP Plant Status Date: September 26, 2016 : 50.0 Status: Under development Do you have more information, corrections, or comments? Background Technology: Power tower Status: Under development Country: China City: Gonghe Region: Qinghai Province

Evaluation of thermokarst lake water balance in the Qinghai-Tibet Plateau via isotope tracers.

PubMed

Gao, Zeyong; Niu, Fujun; Lin, Zhanju; Luo, Jing; Yin, Guoan; Wang, Yibo

2018-04-24

Thermokarst lakes are a ubiquitous landscape feature, which widely distributed in the pan-arctic and some low latitude regions, and are associated with regional hydrological processes. The studies were taken to obtain a better understanding of the water balance of thermokarst lakes in the Qinghai-Tibet Plateau (QTP) in order to gain insight of the regional hydrological cycle. The characteristics of the stable isotopes δ 18 O and δ D were investigated in precipitation, permafrost meltwater, and thermokarst lake water in the continuous permafrost region of the QTP and analyzed the lake water balance using the isotope mass model. The results showed that the δ D-δ 18 O relationship in the thermokarst lakes (δ D = 5.45 δ 18 O - 18.95) differed from that of the local precipitation (δ D = 8.30 δ 18 O + 18.49) and permafrost meltwater (δ D = 5.78 δ 18 O - 23.41), and the mean isotope compositions in the thermokarst lakes were -7.2‰ in δ 18 O and -58.0‰ in δ D. The more positive isotope signals in thermokarst lakes than in the precipitation and permafrost meltwater revealed that the lakes had experienced stronger isotope enrichment. Additionally, the evaporation-to-inflow ratio (E/I) values were < 1 in most of the thermokarst lakes (84%), which might be explained by the recent expansion of the lake surfaces. However, 16% of the thermokarst lakes had shrunk, owing to thermokarst erosion, lateral expansion as the temperature increases, and lower recharge volume. Moreover, precipitation on the lake surface was only 14-18% of the inflow volume in the thermokarst lakes, and the surface-subsurface inflow and permafrost meltwater are very important for recharging the lakes and maintaining the water balance. The results of this study provide a comprehensive understanding of the influence of climate warming on hydrological processes in the permafrost regions in the QTP. Copyright © 2018 Elsevier B.V. All rights reserved.

Starch granule-associated proteins of hull-less barley (Hordeum vulgare L.) from the Qinghai-Tibet Plateau in China.

PubMed

Wang, Chun-Ping; Pan, Zhi-Fen; Nima, Zha-Xi; Tang, Ya-Wei; Cai, Peng; Liang, Jun-Jun; Deng, Guang-Bing; Long, Hai; Yu, Mao-Qun

2011-03-15

The starch granule-associated proteins (SGAPs) are the minor components of the starch granules and a majority of them are believed to be starch biosynthetic enzymes. The Qinghai-Tibet Plateau in China, one of the centres of origin of cultivated barley, is abundant in hull-less barley resources which exhibit high polymorphism in SGAPs. The SGAPs of hull-less barley from Qinghai-Tibet Plateau were analysed by one-dimensional (1-D) SDS-PAGE, 2-D PAGE and ESI-Q-TOF MS/MS. In the 1-D SDS-PAGE gel, four proteins including a 80 kDa starch synthase, actin, actin 4 and ATP synthase β-subunit were identified as novel SGAPs. A total of six different bands were identified as starch granule-bound starch synthase I (GBSSI) and the segregation of the novel GBSSI bands in F(1) and F(2) seeds derived from yf127 × yf70 was in accordance with Mendel's law. In the 2-D PAGE gel, 92 spots were identified as 42 protein species which could be classified into 15 functional groups. Thirteen protein species were identified as SGAPs for the first time and multiple spots were identified as GBSSI. This study revealed novel SGAPs in hull-less barley from the Qinghai-Tibet Plateau in China and these will be significant in further studies of starch biosynthesis in barley. Copyright © 2011 Society of Chemical Industry.

Contrasting Distributions of Bacterial Branched Tetraethers along a Soil-River-Lake Transect in the Arid Region of Northwestern China

NASA Astrophysics Data System (ADS)

Lu, J.

2016-12-01

Understanding the transport of branched glycerol dialkyl glycerol tetraethers (brGDGTs) along the soil-river-lake transect is of vital importance, which helps discriminate the autochthonous from allochthonous contribution of brGDGTs in lake and river environment and favors the application of brGDGT-based proxies in paleo-reconstruction. We collected the sediment samples from the Qinghai Lake, the largest saline lake in China, as well as the river sediments and catchment soils, to examine the difference in the distribution of 5- vs. 6-methyl brGDGTs along the soil-river-lake transect. The brGDGT distributions were found to show a large variation along the transect, which can be reflected by the MBT'-derived indices and IR (isomer ratio) indices. There is a considerable difference in brGDGT distributions between soil and the river sediment. The inflowing rivers likely receive terrestrial brGDGT input to a variable degree. BrGDGTs in the Buha river are primarily of autochthonous origin whereas other ephemeral streams, like the Heima river, exhibit a similar brGDGT distribution to the surrounding soils, reflecting that these compounds are likely derived from soils. A higher quantity of 6-methyl brGDGTs and brGDGT-Ia was observed in the lake than in the river sediments, pointing to a preferential degradation of 5-methyl brGDGTs and/or an increase of in situ production of 6-methyl brGDGTs in the lake. Besides the difference in brGDGT distributions caused by the transportation and in situ production along the transect, we also identified the difference caused by several driving factors in different environments. In arid and alkaline soils, both CBT' and IR indices have strong correlations with soil pH even within the narrow pH range. However, we find a clear relationship of CBT with water salinity in Buha river. The difference in soil and river leads to a complicated interpretation for the CBT (CBT') index. In the lake, the MBT' (specially represented by MBT'5ME and MBT'6

Serological survey of Toxoplasma gondii in Tibetan mastiffs (Canis lupus familiaris) and yaks (Bos grunniens) in Qinghai, China

PubMed Central

2012-01-01

Background Toxoplasma gondii is an amphixenosis which has extensive hosts. In recent years, the prevalence of T. gondii in China has been reported, while little is known on the survey of T. gondii infection in northwest China, especially in yaks (Bos grunniens) and Tibetan mastiffs (Canis lupus familiaris). The current study survey the infection of T. gondii in Tibetan mastiffs and yaks in Qinghai Province, China. Methods The indirect hemagglutination test (IHAT) was used to examine T. gondii antibodies in 1 795 serums, including 192 Tibetan mastiffs and 1603 yaks in Qinghai Province, China. Results In this study, the seroprevalence of T. gondii infection was 8.52%. Twenty (10.42%) of 192 serums of Tibetan mastiffs and 133 (8.30%) of 1603 serums of yaks were seropositive. The seroprevalence of T.gondii infection in Tibetan mastiffs in breeding farm (1.08%) was lower than that in the field (19.19%), and the difference was statistically significant (P <0.05). The seroprevalence of antibodies to T.gondii in yaks ranged from 5.45% to 13.28% among the four different areas. The seroprevalence in different age groups were determined with apparent association. Conclusions The results indicated that T.gondii infection was prevalent in Tibetan mastiffs and yaks, which have implications for public health in this region. To our knowledge, this is the first seroprevalence survey of Tibetan mastiffs infected by T. gondii in The People’s Republic of China. PMID:22330277

The impacts of climate change and human activities on grassland productivity in Qinghai Province, China

NASA Astrophysics Data System (ADS)

Yin, Fang; Deng, Xiangzheng; Jin, Qin; Yuan, Yongwei; Zhao, Chunhong

2014-03-01

Qinghai Province, which is the source of three major rivers (i.e., Yangtze River, Yellow River and Lancang River) in East Asia, has experienced severe grassland degradation in past decades. The aim of this work was to analyze the impacts of climate change and human activities on grassland ecosystem at different spatial and temporal scales. For this purpose, the regression and residual analysis were used based on the data from remote sensing data and meteorological stations. The results show that the effect of climate change was much greater in the areas exhibiting vigorous vegetation growth. The grassland degradation was strongly correlated with the climate factors in the study area except Haixi Prefecture. Temporal and spatial heterogeneity in the quality of grassland were also detected, which was probably mainly because of the effects of human activities. In the 1980s, human activities and grassland vegetation growth were in equilibrium, which means the influence of human activities was in balance with that of climate change. However, in the 1990s, significant grassland degradation linked to human activities was observed, primarily in the Three-River Headwaters Region. Since the 21st century, this adverse trend continued in the Qinghai Lake area and near the northern provincial boundaries, opposite to what were observed in the eastern part of study. These results are consistent with the currently status of grassland degradation in Qinghai Province, which could serve as a basis for the local grassland management and restoration programs.

Atmospheric oxalic acid and related secondary organic aerosols in Qinghai Lake, a continental background site in Tibet Plateau

NASA Astrophysics Data System (ADS)

Meng, Jingjing; Wang, Gehui; Li, Jianjun; Cheng, Chunlei; Cao, Junji

2013-11-01

Summertime PM2.5 aerosols collected from Qinghai Lake (3200 m a.s.l.), a remote continental site in the northeastern part of Tibetan Plateau, were analyzed for dicarboxylic acids (C2-C11), ketocarboxylic acids and α-dicarbonyals. Oxalic acid (C2) is the dominant dicarboxylic acid in the samples, followed by malonic, succinic and azelaic acids. Total dicarboxylic acids (231 ± 119 ng m-3), ketocarboxylic acids (8.4 ± 4.3 ng m-3), and α-dicarbonyls (2.7 ± 2.1 ng m-3) at the Tibetan background site are 2-5 times less than those detected in lowland areas such as 14 Chinese megacities. Compared to those in other urban and marine areas enhancements in relative abundances of C2/total diacids and diacids-C/WSOC of the PM2.5 samples suggest that organic aerosols in the region are more oxidized due to strong solar radiation. Molecular compositions and air mass trajectories demonstrate that the above secondary organic aerosols in the Qinghai Lake atmosphere are largely derived from long-range transport. Ratios of oxalic acid, glyoxal and methylglyoxal to levoglucosan in PM2.5 aerosols emitted from household burning of yak dung, a major energy source for Tibetan in the region, are 30-400 times lower than those in the ambient air, which further indicates that primary emission from biomass burning is a negligible source of atmospheric oxalic acid and α-dicarbonyls at this background site.

Radiocarbon reservoir between charred seeds and fish bone in Neolithic sites, northeastern Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Zhou, A.; Dong, G.; Ren, L.

2017-12-01

Many efforts have been done to understand the reservoir effect of Qinghai Lake, yet no agreement has been reached. Five archaeological sites, located around the junction between the estuary of Rivers and Qinghai Lake, are the earliest Neolithic Age sites in the Qinghai- Tibetan Plateau (QTP), which is critical for understanding patterns of prehistoric human inhabitation in the high plateau extreme environments. This study compares radiocarbon dates of fish bones and terrestrial plant remains uncovered from the same archaeological strata to see whether there was reservoir effect reference to reliable data. Results demonstrate that there were reservoir effects ranging from 300 to 600 years back to 3600 years ago, nevertheless, no reservoir was observed of the modern fish. Besides, stable isotopic analysis illustrated that modern fish consumed similar food to those of millennias ago.

A multi-characteristic based algorithm for classifying vegetation in a plateau area: Qinghai Lake watershed, northwestern China

NASA Astrophysics Data System (ADS)

Ma, Weiwei; Gong, Cailan; Hu, Yong; Li, Long; Meng, Peng

2015-10-01

Remote sensing technology has been broadly recognized for its convenience and efficiency in mapping vegetation, particularly in high-altitude and inaccessible areas where there are lack of in-situ observations. In this study, Landsat Thematic Mapper (TM) images and Chinese environmental mitigation satellite CCD sensor (HJ-1 CCD) images, both of which are at 30m spatial resolution were employed for identifying and monitoring of vegetation types in a area of Western China——Qinghai Lake Watershed(QHLW). A decision classification tree (DCT) algorithm using multi-characteristic including seasonal TM/HJ-1 CCD time series data combined with digital elevation models (DEMs) dataset, and a supervised maximum likelihood classification (MLC) algorithm with single-data TM image were applied vegetation classification. Accuracy of the two algorithms was assessed using field observation data. Based on produced vegetation classification maps, it was found that the DCT using multi-season data and geomorphologic parameters was superior to the MLC algorithm using single-data image, improving the overall accuracy by 11.86% at second class level and significantly reducing the "salt and pepper" noise. The DCT algorithm applied to TM /HJ-1 CCD time series data geomorphologic parameters appeared as a valuable and reliable tool for monitoring vegetation at first class level (5 vegetation classes) and second class level(8 vegetation subclasses). The DCT algorithm using multi-characteristic might provide a theoretical basis and general approach to automatic extraction of vegetation types from remote sensing imagery over plateau areas.

The Impact of Afforestation on Soil Organic Carbon Sequestration on the Qinghai Plateau, China

PubMed Central

Shi, Sheng-wei; Han, Peng-fei; Zhang, Ping; Ding, Fan; Ma, Cheng-lin

2015-01-01

Afforestation, the conversion of non-forested land into forest, is widespread in China. However, the dynamics of soil organic carbon (SOC) after afforestation are not well understood, especially in plateau climate zones. For a total of 48 shrub- and/or tree-dominated afforestation sites on the Qinghai Plateau, Northwestern China, post-afforestation changes in SOC, total nitrogen (TN), the carbon-to-nitrogen ratio (C/N) and soil bulk density (BD) were investigated to a soil depth of 60 cm using the paired-plots method. SOC and TN accumulated at rates of 138.2 g C m-2 yr-1 and 4.6 g N m-2 yr-1, respectively, in shrub-dominated afforestation sites and at rates of 113.3 g C m-2 yr--1 and 6.7 g N m-2yr-1, respectively, in tree-dominated afforestation sites. Soil BD was slightly reduced in all layers in the shrub-dominated afforestation plots, and significantly reduced in soil layers from 0–40cm in the tree-dominated afforestation plots. The C/N ratio was higher in afforested sites relative to the reference sites. SOC accumulation was closely related to TN accumulation following afforestation, and the inclusion of N-fixing species in tree-dominated afforestation sites additionally increased the soil accumulation capacity for SOC (p < 0.05). Multiple regression models including the age of an afforestation plot and total number of plant species explained 75% of the variation in relative SOC content change at depth of 0–20 cm, in tree-dominated afforestation sites. We conclude that afforestation on the Qinghai Plateau is associated with great capability of SOC and TN sequestration. This study improves our understanding of the mechanisms underlying SOC and TN accumulation in a plateau climate, and provides evidence on the C sequestration potentials associated with forestry projects in China. PMID:25706724

The impact of afforestation on soil organic carbon sequestration on the Qinghai Plateau, China.

PubMed

Shi, Sheng-wei; Han, Peng-fei; Zhang, Ping; Ding, Fan; Ma, Cheng-lin

2015-01-01

Afforestation, the conversion of non-forested land into forest, is widespread in China. However, the dynamics of soil organic carbon (SOC) after afforestation are not well understood, especially in plateau climate zones. For a total of 48 shrub- and/or tree-dominated afforestation sites on the Qinghai Plateau, Northwestern China, post-afforestation changes in SOC, total nitrogen (TN), the carbon-to-nitrogen ratio (C/N) and soil bulk density (BD) were investigated to a soil depth of 60 cm using the paired-plots method. SOC and TN accumulated at rates of 138.2 g C m(-2) yr(-1) and 4.6 g N m(-2) yr(-1), respectively, in shrub-dominated afforestation sites and at rates of 113.3 g C m(-2) yr(-1) and 6.7 g N m(-2) yr(-1), respectively, in tree-dominated afforestation sites. Soil BD was slightly reduced in all layers in the shrub-dominated afforestation plots, and significantly reduced in soil layers from 0-40cm in the tree-dominated afforestation plots. The C/N ratio was higher in afforested sites relative to the reference sites. SOC accumulation was closely related to TN accumulation following afforestation, and the inclusion of N-fixing species in tree-dominated afforestation sites additionally increased the soil accumulation capacity for SOC (p < 0.05). Multiple regression models including the age of an afforestation plot and total number of plant species explained 75% of the variation in relative SOC content change at depth of 0-20 cm, in tree-dominated afforestation sites. We conclude that afforestation on the Qinghai Plateau is associated with great capability of SOC and TN sequestration. This study improves our understanding of the mechanisms underlying SOC and TN accumulation in a plateau climate, and provides evidence on the C sequestration potentials associated with forestry projects in China.

Isolation and Classification of Fungal Whitefly Entomopathogens from Soils of Qinghai-Tibet Plateau and Gansu Corridor in China.

PubMed

Dong, Tingyan; Zhang, Bowen; Jiang, Yanfang; Hu, Qiongbo

2016-01-01

Qinghai-Tibet Plateau and Gansu Corridor of China with distinct geographic and climatic conditions are remote and less disturbed by humans, in which are likely to find some new strains of fungal entomopathogens against B-biotype whiteflies that is a very important invading pest worldwide. In this research, nineteen strains among six species of entomogenous fungi were isolated from the soil samples collected from 32 locations in Qinghai-Tibet Plateau and Gansu Corridor. From the data of isolation rates, it was indicated that the good biodiversity of entomogenous fungi was found in the soil covered good vegetations. On the contrary, no strains were isolated from the desert areas. In addition, the dominant species, Isaria fumosorosea and Metarhizium anisopliae var. anisopliae in the Qinghai-Tibet Plateau are different from the strains of other places based on ITS genetic homology analysis. It was verified that the Qinghai-Tibet Plateau area was less disturbed by human, and the fungi in this place exchanged less compared with other regional species. All of these strains showed the pathogenicity against the B-biotype whitefly with the mortality of more than 30%. However, a few strains of Paecilomyces lilacinus, Lecanicillium psalliotae, Aspergillus ustus, I. fumosorosea and M. anisopliae var. anisopliae had better virulence with LC50s of 0.36-26.44×106 spores/mL on post-treatment day 6-7. Especially, the L. psalliotae strain LpTS01 was the greatest virulence with LC50 of 0.36×106spores/mL and LT50 of 4.23d. Our research thus presents some new insights to discover new entomopathogenic fungal strains used for B-biotype whitefly biocontrol.

Isolation and Classification of Fungal Whitefly Entomopathogens from Soils of Qinghai-Tibet Plateau and Gansu Corridor in China

PubMed Central

Jiang, Yanfang; Hu, Qiongbo

2016-01-01

Qinghai-Tibet Plateau and Gansu Corridor of China with distinct geographic and climatic conditions are remote and less disturbed by humans, in which are likely to find some new strains of fungal entomopathogens against B-biotype whiteflies that is a very important invading pest worldwide. In this research, nineteen strains among six species of entomogenous fungi were isolated from the soil samples collected from 32 locations in Qinghai-Tibet Plateau and Gansu Corridor. From the data of isolation rates, it was indicated that the good biodiversity of entomogenous fungi was found in the soil covered good vegetations. On the contrary, no strains were isolated from the desert areas. In addition, the dominant species, Isaria fumosorosea and Metarhizium anisopliae var. anisopliae in the Qinghai-Tibet Plateau are different from the strains of other places based on ITS genetic homology analysis. It was verified that the Qinghai-Tibet Plateau area was less disturbed by human, and the fungi in this place exchanged less compared with other regional species. All of these strains showed the pathogenicity against the B-biotype whitefly with the mortality of more than 30%. However, a few strains of Paecilomyces lilacinus, Lecanicillium psalliotae, Aspergillus ustus, I. fumosorosea and M. anisopliae var. anisopliae had better virulence with LC50s of 0.36–26.44×106 spores/mL on post-treatment day 6–7. Especially, the L. psalliotae strain LpTS01 was the greatest virulence with LC50 of 0.36×106spores/mL and LT50 of 4.23d. Our research thus presents some new insights to discover new entomopathogenic fungal strains used for B-biotype whitefly biocontrol. PMID:27228109

Contrasting response of coexisting plant's water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China.

PubMed

Wu, Huawu; Li, Jing; Li, Xiao-Yan; He, Bin; Liu, Jinzhao; Jiang, Zhiyun; Zhang, Cicheng

2018-01-01

Understanding species-specific changes in water-use patterns under recent climate scenarios is necessary to predict accurately the responses of seasonally dry ecosystems to future climate. In this study, we conducted a precipitation manipulation experiment to investigate the changes in water-use patterns of two coexisting species (Achnatherum splendens and Allium tanguticum) to alterations in soil water content (SWC) resulting from increased and decreased rainfall treatments. The results showed that the leaf water potential (Ψ) of A. splendens and A. tanguticum responded to changes in shallow and middle SWC at both the control and treatment plots. However, A. splendens proportionally extracted water from the shallow soil layer (0-10cm) when it was available but shifted to absorbing deep soil water (30-60 cm) during drought. By contrast, the A. tanguticum did not differ significantly in uptake depth between treatment and control plots but entirely depended on water from shallow soil layers. The flexible water-use patterns of A.splendens may be a key factor facilitating its dominance and it better acclimates the recent climate change in the alpine grassland community around Qinghai Lake.

Effect of degradation intensity on grassland ecosystem services in the alpine region of Qinghai-Tibetan Plateau, China.

PubMed

Wen, Lu; Dong, Shikui; Li, Yuanyuan; Li, Xiaoyan; Shi, Jianjun; Wang, Yanlong; Liu, Demei; Ma, Yushou

2013-01-01

The deterioration of alpine grassland has great impact on ecosystem services in the alpine region of Qinghai-Tibetan Plateau. However, the effect of grassland degradation on ecosystem services and the consequence of grassland deterioration on economic loss still remains a mystery. So, in this study, we assessed four types of ecosystem services following the Millennium Ecosystem Assessment classification, along a degradation gradient. Five sites of alpine grassland at different levels of degradation were investigated in Guoluo Prefecture of Qinghai Province, China. The species composition, aboveground biomass, soil total organic carbon (TOC), and soil total nitrogen (TN) were tested to evaluate major ecological services of the alpine grassland. We estimated the value of primary production, carbon storage, nitrogen recycling, and plant diversity. The results show the ecosystem services of alpine grassland varied along the degradation gradient. The ecosystem services of degraded grassland (moderate, heavy and severe) were all significantly lower than non-degraded grassland. Interestingly, the lightly degraded grassland provided more economic benefit from carbon maintenance and nutrient sequestration compared to non-degraded. Due to the destruction of the alpine grassland, the economic loss associated with decrease of biomass in 2008 was $198/ha. Until 2008, the economic loss caused by carbon emissions and nitrogen loss on severely degraded grassland was up to $8 033/ha and $13 315/ha, respectively. Urgent actions are required to maintain or promote the ecosystem services of alpine grassland in the Qinghai-Tibetan Plateau.

Effect of Degradation Intensity on Grassland Ecosystem Services in the Alpine Region of Qinghai-Tibetan Plateau, China

PubMed Central

Wen, Lu; Dong, Shikui; Li, Yuanyuan; Li, Xiaoyan; Shi, Jianjun; Wang, Yanlong; Liu, Demei; Ma, Yushou

2013-01-01

The deterioration of alpine grassland has great impact on ecosystem services in the alpine region of Qinghai-Tibetan Plateau. However, the effect of grassland degradation on ecosystem services and the consequence of grassland deterioration on economic loss still remains a mystery. So, in this study, we assessed four types of ecosystem services following the Millennium Ecosystem Assessment classification, along a degradation gradient. Five sites of alpine grassland at different levels of degradation were investigated in Guoluo Prefecture of Qinghai Province, China. The species composition, aboveground biomass, soil total organic carbon (TOC), and soil total nitrogen (TN) were tested to evaluate major ecological services of the alpine grassland. We estimated the value of primary production, carbon storage, nitrogen recycling, and plant diversity. The results show the ecosystem services of alpine grassland varied along the degradation gradient. The ecosystem services of degraded grassland (moderate, heavy and severe) were all significantly lower than non-degraded grassland. Interestingly, the lightly degraded grassland provided more economic benefit from carbon maintenance and nutrient sequestration compared to non-degraded. Due to the destruction of the alpine grassland, the economic loss associated with decrease of biomass in 2008 was $198/ha. Until 2008, the economic loss caused by carbon emissions and nitrogen loss on severely degraded grassland was up to $8 033/ha and $13 315/ha, respectively. Urgent actions are required to maintain or promote the ecosystem services of alpine grassland in the Qinghai-Tibetan Plateau. PMID:23469278

Environmental cost and pollution risk caused by the industrial transfer in Qinghai Province

NASA Astrophysics Data System (ADS)

Jiang, Qun'ou; Tang, Chengcai; Zhan, Jinyan; Zhang, Wei; Wu, Feng

2014-09-01

With the rising pressure due to energy consumption and costs of environmental protection and recovery, industrial transfer from the eastern to central and western areas has surged in China. However, extremely fragile ecological conditions and severe water shortage are significant hurdles for industry development in Western China. Whether the vulnerable environment can bear the pollution caused by the transferred industry from Eastern China becomes a significant issue. This study firstly estimates energy and environmental costs in different areas of China, and assesses the necessity to upgrade the industrial structure of Qinghai Province. Then the emissions of waste water, waste gas, and smoke caused by transferred industries are calculated by Input-Output Model. On the basis of the effect analysis of waste emission on environment, pollution risks of Qinghai province are assessed. The results illustrate that the costs of environmental protection and recovery in China have a gradient distribution, of which the energy efficiency is lower while environmental costs are higher in Western China. Industrial structure adjustment has different impacts on the pollution of different sectors. Although the development of machinery and equipment, hotels and catering services, and real estate, leasing, and business services has increased the emission of pollutants, it is offset by the decreasing emissions caused by other industries such as construction and metal products. Therefore, although economic development will increase environmental pollution, industrial adjustments can effectively decrease waste water and waste gas emissions to reduce the pollution risk. It should be noted that there are still tremendous challenges for industrial transfer in Qinghai Province to coordinate the environment and industry development.

Contrasting response of coexisting plant’s water-use patterns to experimental precipitation manipulation in an alpine grassland community of Qinghai Lake watershed, China

PubMed Central

Li, Xiao-Yan; He, Bin; Liu, Jinzhao; Jiang, Zhiyun; Zhang, Cicheng

2018-01-01

Understanding species-specific changes in water-use patterns under recent climate scenarios is necessary to predict accurately the responses of seasonally dry ecosystems to future climate. In this study, we conducted a precipitation manipulation experiment to investigate the changes in water-use patterns of two coexisting species (Achnatherum splendens and Allium tanguticum) to alterations in soil water content (SWC) resulting from increased and decreased rainfall treatments. The results showed that the leaf water potential (Ψ) of A. splendens and A. tanguticum responded to changes in shallow and middle SWC at both the control and treatment plots. However, A. splendens proportionally extracted water from the shallow soil layer (0–10cm) when it was available but shifted to absorbing deep soil water (30–60 cm) during drought. By contrast, the A. tanguticum did not differ significantly in uptake depth between treatment and control plots but entirely depended on water from shallow soil layers. The flexible water-use patterns of A.splendens may be a key factor facilitating its dominance and it better acclimates the recent climate change in the alpine grassland community around Qinghai Lake. PMID:29677195

Carbon accumulation and sequestration of lakes in China during the Holocene.

PubMed

Wang, Mei; Chen, Huai; Yu, Zicheng; Wu, Jianghua; Zhu, Qiu'an; Peng, Changhui; Wang, Yanfen; Qin, Boqiang

2015-12-01

Understanding the responses of lake systems to past climate change and human activity is critical for assessing and predicting the fate of lake carbon (C) in the future. In this study, we synthesized records of the sediment accumulation from 82 lakes and of C sequestration from 58 lakes with direct organic C measurements throughout China. We also identified the controlling factors of the long-term sediment and C accumulation dynamics in these lakes during the past 12 ka (1 ka = 1000 cal yr BP). Our results indicated an overall increasing trend of sediment and C accumulation since 12 ka, with an accumulation peak in the last couple of millennia for lakes in China, corresponding to terrestrial organic matter input due to land-use change. The Holocene lake sediment accumulation rate (SAR) and C accumulation rate (CAR) averaged (mean ± SE) 0.47 ± 0.05 mm yr(-1) and 7.7 ± 1.4 g C m(-2)  yr(-1) in China, respectively, comparable to the previous estimates for boreal and temperate regions. The SAR for lakes in the East Plain of subtropical China (1.05 ± 0.28 mm yr(-1) ) was higher than those in other regions (P < 0.05). However, CAR did not vary significantly among regions. Overall, the variability and history of climate and anthropogenic interference regulated the temporal and spatial dynamics of sediment and C sequestration for lakes in China. We estimated the total amount of C burial in lakes of China as 8.0 ± 1.0 Pg C. This first estimation of total C storage and dynamics in lakes of China confirms the importance of lakes in land C budget in monsoon-influenced regions. © 2015 John Wiley & Sons Ltd.

Socio-economic burden of parasitic infections in yaks from 1984 to 2017 on Qinghai Tibetan Plateau of China-A review.

PubMed

Li, Kun; Shahzad, Muhammad; Zhang, Hui; Jiang, Xiong; Mehmood, Khalid; Zhao, Xiaodong; Li, Jiakui

2018-07-01

Yak is an important animal for the Tibetans at Qinghai-Tibetan Plateau of China. The burden of parasitic diseases has been a major threat to the health of yaks at this region presenting a considerable socio-economic losses and impact to yak production and local nomads. Keeping in view, we collected the published papers from 1984 to 2017 on major parasitic infections in yaks by electronic literature search from five databases including CNKI, Google, PubMed, Science Direct and Web of Science. The prevalence of Eimeria, Babesia, Theileria, Hypodermosis, Cystic echinococcosis, Alveolar echinococcosis, Toxoplasma gondii, Neospora caninum, Cryptosporidium, Giardia duodenalis, Enterocytozoon bieneusi, Toxocara vitulorum, and Fascioliasis infection in yaks was found to be 48.02%, 13.06%, 36.11%, 59.85%, 16.93%, 0.99%, 20.50%, 5.14%, 10.00%, 3.68%, 4.07%, 22.23% and 28.7% respectively. Data presented are contemplated to enhance our current understanding on the major parasitic diseases of yaks at Qinghai Tibetan plateau, China. The main aim of this effort is to ameliorate the effects of the parasitic burden in this specie; so that, the attempts are made to minimize the incidence of these infections in future to raise the socio-economic levels of local community. Copyright © 2018 Elsevier B.V. All rights reserved.

Anaemia among Students of Rural China's Elementary Schools: Prevalence and Correlates in Ningxia and Qinghai's Poor Counties

PubMed Central

Luo, Renfu; Liu, Chengfang; Zhao, Qiran; Shi, Yaojiang; Miller, Grant; Yu, Elaine; Sharbono, Brian; Medina, Alexis; Rozelle, Scott; Martorell, Reynaldo

2011-01-01

Although the past few decades have seen rising incomes and increased government attention to rural development, many children in rural China still lack regular access to micronutrient-rich diets. Insufficient diets and poor knowledge of nutrition among the poor result in nutritional problems, including iron-deficiency anaemia, which adversely affect attention and learning of students in school. Little research has been conducted in China documenting the prevalence of nutritional problems among vulnerable populations, such as school-age children, in rural areas. The absence of programmes to combat anaemia among students might be interpreted as a sign that the Government does not recognize its severity. The goals of this paper were to measure the prevalence of anaemia among school-age children in poor regions of Qinghai and Ningxia, to identify individual-, householdand school-based factors that correlate with anaemia in this region, and to report on the correlation between the anaemic status and the physical, psychological and cognitive outcomes. The results of a cross-sectional survey are reported here. The survey involved over 4,000 fourth and fifth grade students from 76 randomly-selected elementary schools in 10 poor counties in rural Qinghai province and Ningxia Hui Autonomous Region, located in the northwest region of China. Data were collected using a structured questionnaire and standardized tests. Trained professional nurses administered haemoglobin (Hb) tests (using Hemocue finger prick kits) and measured heights and weights of children. The baseline data showed that the overall anaemia rate was 24.9%, using the World Health Organization's blood Hb cut-offs of 120 g/L for children aged 12 years and older and 115 g/L for children aged 11 years and under. Children who lived and ate at school had higher rates of anaemia, as did children whose parents worked in farms or were away from home. Children with parents who had lower levels of education were more

Interplay between the Westerlies and Asian monsoon recorded in Lake Qinghai sediments since 32 ka

PubMed Central

An, Zhisheng; Colman, Steven M.; Zhou, Weijian; Li, Xiaoqiang; Brown, Eric T.; Jull, A. J. Timothy; Cai, Yanjun; Huang, Yongsong; Lu, Xuefeng; Chang, Hong; Song, Yougui; Sun, Youbin; Xu, Hai; Liu, Weiguo; Jin, Zhangdong; Liu, Xiaodong; Cheng, Peng; Liu, Yu; Ai, Li; Li, Xiangzhong; Liu, Xiuju; Yan, Libin; Shi, Zhengguo; Wang, Xulong; Wu, Feng; Qiang, Xiaoke; Dong, Jibao; Lu, Fengyan; Xu, Xinwen

2012-01-01

Two atmospheric circulation systems, the mid-latitude Westerlies and the Asian summer monsoon (ASM), play key roles in northern-hemisphere climatic changes. However, the variability of the Westerlies in Asia and their relationship to the ASM remain unclear. Here, we present the longest and highest-resolution drill core from Lake Qinghai on the northeastern Tibetan Plateau (TP), which uniquely records the variability of both the Westerlies and the ASM since 32 ka, reflecting the interplay of these two systems. These records document the anti-phase relationship of the Westerlies and the ASM for both glacial-interglacial and glacial millennial timescales. During the last glaciation, the influence of the Westerlies dominated; prominent dust-rich intervals, correlated with Heinrich events, reflect intensified Westerlies linked to northern high-latitude climate. During the Holocene, the dominant ASM circulation, punctuated by weak events, indicates linkages of the ASM to orbital forcing, North Atlantic abrupt events, and perhaps solar activity changes. PMID:22943005

amoA-encoding archaea and thaumarchaeol in the lakes on the northeastern Qinghai-Tibetan Plateau, China

PubMed Central

Yang, Jian; Jiang, Hongchen; Dong, Hailiang; Wang, Huanye; Wu, Geng; Hou, Weiguo; Liu, Weiguo; Zhang, Chuanlun; Sun, Yongjuan; Lai, Zhongping

2013-01-01

All known ammonia-oxidizing archaea (AOA) belong to the phylum Thaumarchaeota within the domain Archaea. AOA possess the diagnostic amoA gene (encoding the alpha subunit of ammonia monooxygenase) and produce lipid biomarker thaumarchaeol. Although the abundance and diversity of amoA gene-encoding archaea (AEA) in freshwater lakes have been well-studied, little is known about AEA ecology in saline/hypersaline lakes. In this study, the distribution of the archaeal amoA gene and thaumarchaeol were investigated in nine Qinghai–Tibetan lakes with a salinity range from freshwater to salt-saturation (salinity: 325 g L-1). The results showed that the archaeal amoA gene was present in hypersaline lakes with salinity up to 160 g L-1. The archaeal amoA gene diversity in Tibetan lakes was different from those in other lakes worldwide, suggesting Tibetan lakes (high elevation, strong ultraviolet, and dry climate) may host a unique AEA population of different evolutionary origin from those in other lakes. Thaumarchaeol was present in all of the studied hypersaline lakes, even in those where no AEA amoA gene was observed. Future research is needed to determine the ecological function of AEA and possible sources of thaumarchaeol in the Qinghai–Tibetan hypersaline lakes. PMID:24273535

Satellite-marked waterfowl reveal migratory connection between H5N1 outbreak areas in China and Mongolia

USGS Publications Warehouse

Prosser, D.J.; Takekawa, John Y.; Newman, S.H.; Yan, B.; Douglas, David C.; Hou, Y.; Xing, Z.; Zhang, Dongxiao; Li, T.; Li, Y.; Zhao, D.; Perry, W.M.; Palm, E.C.

2009-01-01

The role of wild birds in the spread of highly pathogenic avian influenza H5N1 has been greatly debated and remains an unresolved question. However, analyses to determine involvement of wild birds have been hindered by the lack of basic information on their movements in central Asia. Thus, we initiated a programme to document migrations of waterfowl in Asian flyways to inform hypotheses of H5N1 transmission. As part of this work, we studied migration of waterfowl from Qinghai Lake, China, site of the 2005 H5N1 outbreak in wild birds. We examined the null hypothesis that no direct migratory connection existed between Qinghai Lake and H5N1 outbreak areas in central Mongolia, as suggested by some H5N1 phylogeny studies. We captured individuals in 2007 from two of the species that died in the Qinghai Lake outbreaks and marked them with GPS satellite transmitters: Bar-headed Geese Anser indicus (n = 14) and Ruddy Shelduck Tadorna ferruginea (n = 11). Three of 25 marked birds (one Goose and two Shelducks) migrated to breeding grounds near H5N1 outbreak areas in Mongolia. Our results describe a previously unknown migratory link between the two regions and offer new critical information on migratory movements in the region. ?? 2009 British Ornithologists' Union.

The response of lake area and vegetation cover variations to climate change over the Qinghai-Tibetan Plateau during the past 30years.

PubMed

Zhang, Zengxin; Chang, Juan; Xu, Chong-Yu; Zhou, Yang; Wu, Yanhong; Chen, Xi; Jiang, Shanshan; Duan, Zheng

2018-09-01

Lakes and vegetation are important factors of the Earth's hydrological cycle and can be called an "indicator" of climate change. In this study, long-term changes of lakes' area and vegetation coverage in the Qinghai-Tibetan Plateau (QTP) and their relations to the climate change were analyzed by using Mann-Kendall method during the past 30years. Results showed that: 1) the lakes' area of the QTP increased significantly during the past 30years as a whole, and the increasing rates have been dramatically sped up since the year of 2000. Among them, the area of Ayakekumu Lake has the fastest growing rate of 51.35%, which increased from 618km 2 in the 1980s to 983km 2 in the 2010s; 2) overall, the Normalized Difference Vegetation Index (NDVI) increased in the QTP during the past 30years. Above 79% of the area in the QTP showed increasing trend of NDVI before the year of 2000; 3) the air temperature increased significantly, the precipitation increased slightly, and the pan evaporation decreased significantly during the past 30years. The lake area and vegetation coverage changes might be related to the climate change. The shifts in the temporal climate trend occurred around the year 2000 had led the lake area and vegetation coverage increasing. This study is of importance in further understanding the environmental changes under global warming over the QTP. Copyright © 2018 Elsevier B.V. All rights reserved.

Analysis on the Change of Vegetation Coverage in Qinghai Province from 2000 TO 2012

NASA Astrophysics Data System (ADS)

Wang, J.; Yan, Q.; Liu, Z.; Luo, C.

2013-07-01

Qinghai Province is one of the important provinces on the Qinghai-Tibet Plateau in China. Its unique alpine meadow ecosystem makes it become the most concentrated areas of biodiversity in high altitudes in the world. Researching the vegetation coverage and changes of Qinghai province can reflect effectively and timely processing of changes and problems of ecological quality in the region. This research will give a long time series monitoring of the vegetation coverage of Qinghai province based on maximum value composite (MVC) and S-G filtering algorithm using MODIS data of the year of 2000-2012, then analyze the change using coefficient of variability(CV) and trend line analysis. According to research, during the past 13 years, more than half of Qinghai Province's vegetation coverage is well, both the east and south have a high coverage, while the northwest is lower. The changing of vegetation coverage also has showed a steady and improving trend in 13 years. The largest area is slight improved area is about 29.08% of the total area, and the second largest area is significant improved area is about 21.09% of the total area. In this research can learn directly the vegetation coverage and changes of Qinghai province and provide reference and scientific basis for the protection and governance of ecological environment.

[Ichthyofauna and its community diversity in volcanic barrier lakes of Northeast China].

PubMed

Yang, Fu-Yi; Lü, Xian-Guo; Lou, Yan-Jing; Lou, Xiao-Nan; Xue, Bin; Yao, Shu-Chun; Xiao, Hai-Feng

2012-12-01

Based on the investigations of fish resources in Jingpo Lake and Wudalianchi Lakes in 2008-2011 and the historical data, this paper analyzed the characteristics of ichthyofauna and its community diversity in volcanic barrier lakes of Northeast China. The ichthyofauna in the volcanic barrier lakes of Northeast China was consisted of 64 native species, belonging to 47 genera, 16 families, and 9 orders, among which, one species was the second class National protected wild animal, four species were Chinese endemic species, and five species were Chinese vulnerable species. In the 64 recorded species, there were 44 species of Cypriniformes order and 37 species of Cyprinidae family dominated, respectively. The ichthyofauna in the volcanic barrier lakes of Northeast China was formed by 7 fauna complexes, among which, the eastern plain fauna complex was dominant, the common species from the South and the North occupied 53.1%, and the northern endemic species took up 46.9%. The Shannon, Fisher-alpha, Pielou, Margalef, and Simpson indices of the ichthyofauna were 2.078, 4.536, 0.575, 3.723, and 0.269, respectively, and the abundance distribution pattern of native species accorded with lognormal model. The Bray-Curtis, Morisita-Horn, Ochiai, Sørensen, and Whittaker indices between the communities of ichthyofauna in the volcanic barrier lakes of Northeast China and the Jingpo Lake were 0.820, 0.992, 0.870, 0.862 and 0.138, respectively, and those between the communities of ichthyofauna in the volcanic barrier lakes and the Wudalianchi Lakes were 0.210, 0.516, 0.838, 0.825, and 0.175, respectively. The ichthyofauna in volcanic barrier lakes of Northeast China was characterized by the mutual infiltration between the South and the North, and the overlap and transition between the Palaeoarctic realm and the Oricetal realm. It was suggested that the ichthyofauna community species diversity in the volcanic barrier lakes of Northeast China was higher, the species structure was more

Dongting Lake, China

NASA Image and Video Library

2002-09-15

These images show dramatic change in the water at Dongting Lake in Hunan province, China. A flood crest surged down the Yangtze River in late August of this year, but the embankments made by residents there held. The left image was acquired on September 2, 2002 and shows the extent of the lake. The right image was obtained March 19, 2002 before the flooding began. These images were acquired on September 2, 2002 and March 19, 2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet. http://photojournal.jpl.nasa.gov/catalog/PIA03858

Black carbon aerosol characterization in a remote area of Qinghai-Tibetan Plateau, western China.

PubMed

Wang, Qiyuan; Schwarz, J P; Cao, Junji; Gao, Rushan; Fahey, D W; Hu, Tafeng; Huang, R-J; Han, Yongming; Shen, Zhenxing

2014-05-01

The concentrations, size distributions, and mixing states of refractory black carbon (rBC) aerosols were measured with a ground-based Single Particle Soot Photometer (SP2), and aerosol absorption was measured with an Aethalometer at Qinghai Lake (QHL), a rural area in the Northeastern Tibetan Plateau of China in October 2011. The area was not pristine, with an average rBC mass concentration of 0.36 μg STP-m(-3) during the two-week campaign period. The rBC concentration peaked at night and reached the minimal in the afternoon. This diurnal cycle of concentration is negatively correlated with the mixed layer depth and ventilation. When air masses from the west of QHL were sampled in late afternoon to early evening, the average rBC concentration of 0.21 μg STP-m(-3) was observed, representing the rBC level in a larger Tibetan Plateau region because of the highest mixed layer depth. A lognormal primary mode with mass median diameter (MMD) of ~175 nm, and a small secondary lognormal mode with MMD of 470-500 nm of rBC were observed. Relative reduction in the secondary mode during a snow event supports recent work that suggested size dependent removal of rBC by precipitation. About 50% of the observed rBC cores were identified as thickly coated by non-BC material. A comparison of the Aethalometer and SP2 measurements suggests that non-BC species significantly affect the Aethalometer measurements in this region. A scaling factor for the Aethalometer data at a wavelength of 880 nm is therefore calculated based on the measurements, which may be used to correct other Aethalometer datasets collected in this region for a more accurate estimate of the rBC loading. The results present here significantly improve our understanding of the characteristics of rBC aerosol in the less studied Tibetan Plateau region and further highlight the size dependent removal of BC via precipitation. Copyright © 2014 Elsevier B.V. All rights reserved.

Microplastics in Taihu Lake, China.

PubMed

Su, Lei; Xue, Yingang; Li, Lingyun; Yang, Dongqi; Kolandhasamy, Prabhu; Li, Daoji; Shi, Huahong

2016-09-01

In comparison with marine environments, the occurrence of microplastics in freshwater environments is less understood. In the present study, we investigated microplastic pollution levels during 2015 in Taihu Lake, the third largest Chinese lake located in one of the most developed areas of China. The abundance of microplastics reached 0.01 × 10(6)-6.8 × 10(6) items/km(2) in plankton net samples, 3.4-25.8 items/L in surface water, 11.0-234.6 items/kg dw in sediments and 0.2-12.5 items/g ww in Asian clams (Corbicula fluminea). The average abundance of microplastics was the highest in plankton net samples from the southeast area of the lake and in the sediments from the northwest area of the lake. The northwest area of the lake was the most heavily contaminated area of the lake, as indicated by chlorophyll-α and total phosphorus. The microplastics were dominated by fiber, 100-1000 μm in size and cellophane in composition. To our best knowledge, the microplastic levels measured in plankton net samples collected from Taihu Lake were the highest found in freshwater lakes worldwide. The ratio of the microplastics in clams to each sediment sample ranged from 38 to 3810 and was negatively correlated to the microplastic level in sediments. In brief, our results strongly suggest that high levels of microplastics occurred not only in water but also in organisms in Taihu Lake. Copyright © 2016 Elsevier Ltd. All rights reserved.

A 150 year precipitation record preserved in lake sediments of Lake Gahai in the Qaidam Basin, northwest China

NASA Astrophysics Data System (ADS)

Li, X.

2012-12-01

A 150 year precipitation record preserved in lake sediments of Lake Gahai in the Qaidam Basin, northwest China Li Xiangzhong a, Liu Weiguoa, b a State Key Laboratory of Loess and Quaternary Geology, IEE, CAS, Xi'an, 710075, China b School of Human Settlement and Civil Engineering, Xi'an Jiaotong University, Xi'an, 710049, China Abstract Usually, the oxygen isotopic compositions of ostracods from the lake sediments are interpreted as changes in effective precipitation, temperature and evaporation/input water ratio in a sub-arid or arid area. Here, we compare a 150-year-long oxygen-isotope record that was derived from ostracod carbonate from the sediment core (in a seven-year resolution) of Lake Gahai in the Qaidam Basin with meteorological data (precipitation) and tree-ring evidence for changing precipitation. Our results show that the increased precipitation accompanied a shift to less positive δ18O values in the lake water, and hence of the ostracod shells, whereas decreased precipitation coincides with the opposite in Lake Gahai over the past ~150 years. The sole occurrence of the ostracod E. mareotica also indicates that the lake's salinity may have experienced no marked change over the past 150 years. Therefore, we conclude that the oxygen isotopic compositions of ostracod shells can be used to indicate changes in precipitation for paleoclimatic reconstruction over a short time scale in Lake Gahai. Keywords: oxygen isotope; ostracod; precipitation; Lake Gahai, Qaidam Basin

A world-class target for ICDP drilling at Lake Nam Co, Tibetan Plateau, China: progresses and perspectives

NASA Astrophysics Data System (ADS)

Zhu, L.; Wang, J.; Daut, G.; Spiess, V.; Haberzettl, T.; Schulze, N.; Ju, J.; Lü, X.; Bergmann, F.; Haberkern, J.; Schwalb, A.; Mäusbacher, R.

2017-12-01

Lake Nam Co (ca. 2000 km2, 4718 m a.s.l., maximum depth: 100 m) is located at the interaction zone of the Westerlies and the Indian monsoon on the central Tibetan Plateau. It was part of a mega-lake during Marine Isotope Stage (MIS) 3 before the Last Glacial Maximum. A long term sedimentary record from Nam Co could therefore provide an excellent paleo-environmental sequence for regional and global comparative studies. This will to deepen our understanding of large scale atmospheric circulation shifts and the environmental links between the Tibetan Plateau at low latitudes and the North Atlantic region at high latitudes. A Nam Co deep drilling will fill the gap in two large scale ICDP/IODP drilling transects (N-S: Lake Baikal, Lake Qinghai, Bay of Bengal; W-E: Lake Van, Lake Issyk-Kul, South China Sea, Lake Towuti), which will show the great significance of monsoon dynamics on a long-term scale. Multidisciplinary researches have been conducted since 2005 by a Sino-German cooperative team. The progresses during the last decade are: 1) Detailed bathymetric surveying, including a shallow sediment profiler investigation (Innomar SES 2000 light, ca. 30 m sediment penetration); 2) Paleo-environmental reconstructions covering the past 24 ka; 3) Modern sediment distribution covering the entire lake; 4) Monitoring including water temperature profiles, sediment traps, seasonal airborne pollen collection; 5) Deep seismic survey penetrating up to 800 meters of lake sediments. Based on sediment rates from reference core NC08/01, seismic results show that an age of 500 ka may be reached at 500 m, and >1 Ma at the observed base. Faulting can be clearly detected in the seismic profiles, especially from MIS 5 to early Holocene, and shows the characteristics of normal faults or strike-slip faults. Both rotation of the layers and the close spacing, along with negative and positive offsets of the faults make a transtensional origin of the basin likely. An ICDP workshop proposal was

Gymnocypris przewalskii decreases cytosolic carbonic anhydrase expression to compensate for respiratory alkalosis and osmoregulation in the saline-alkaline lake Qinghai.

PubMed

Yao, Zongli; Guo, Wenfei; Lai, Qifang; Shi, Jianquan; Zhou, Kai; Qi, Hongfang; Lin, Tingting; Li, Ziniu; Wang, Hui

2016-01-01

Naked carp (Gymnocypris przewalskii), endemic to the saline-alkaline Lake Qinghai, have the capacity to tolerate combined high salinity and alkalinity, but migrate to spawn in freshwater rivers each year. In this study, the full-length cDNA of the cytosolic carbonic anhydrase c isoform of G. przewalskii (GpCAc) was amplified and sequenced; mRNA levels and enzyme activity of GpCAc and blood chemistry were evaluated to understand the compensatory responses as the naked carp returned to the saline-alkaline lake after spawning. We found that GpCAc had a total length of 1400 bp and encodes a peptide of 260 amino acids. Comparison of the deduced amino acid sequences and phylogenetic analysis showed that GpCAc was a member of the cytosolic carbonic anhydrase II-like c family. Cytosolic-carbonic-anhydrase-c-specific primers were used to analyze the tissue distribution of GpCAc mRNA expression. Expression of GpCAc mRNA was found in brain, gill, liver, kidney, gut, and muscle tissues, but primarily in the gill and posterior kidney; however, none was evident in red blood cells. Transferring fish from river water to lake water resulted in a respiratory alkalosis, osmolality, and ion rise in the blood, as well as significant decreases in the expression and enzyme activity of GpCAc in both the gill and kidney within 96 h. These results indicate that GpCAc may play an important role in the acclimation to both high salinity and carbonate alkalinity. Specifically, G. przewalskii decreases cytosolic carbonic anhydrase c expression to compensate for a respiratory alkalosis and to aid in osmoregulation during the transition from river to saline-alkaline lake.

Survey, Culture, and Genome Analysis of Ocular Chlamydia trachomatis in Tibetan Boarding Primary Schools in Qinghai Province, China

PubMed Central

Feng, Le; Lu, Xinxin; Yu, Yonghui; Wang, Tao; Luo, Shengdong; Sun, Zhihui; Duan, Qing; Wang, Ningli; Song, Lihua

2017-01-01

Trachoma, the leading infectious cause of blindness worldwide, is an ancient human disease. Its existence in China can be traced back to as early as the twenty-seventh century BC. In modern China, the overall prevalence of trachoma has dramatically reduced, but trachoma is still endemic in many areas of the country. Here, we report that 26 (8%) of 322 students from two rural boarding schools of Qinghai province, west China, were identified as having ocular C. trachomatis infection; and 15 ocular C. trachomatis strains were isolated from these trachoma patients. Chlamydiae in 37 clinical samples were genotyped as type B based on ompA gene analyses. Three ompA variants with one or two in-between SNP differences in the second or fourth variable domain were found. C. trachomatis strains QH111L and QH111R were from the same patient's left and right conjunctival swabs, respectively, but their ompA genes have a non-synonymous base difference in the second variable domain. Moreover, this SNP only exists in this single sample, suggesting QH111L is a newly emerged ompA variant. Interestingly, chromosomal phylogeny analysis found QH111L clusters between a branch of two type B strains and a branch of both A and C strains, but is significantly divergent from both branches. Comparative chromosome analysis found that compared to sequences of reference B/TZ1A828/OT strain, 12 of 22 QH111L's chromosomal genes exhibiting more than nine SNPs have the best homology with reciprocal genes of UGT strains while 9 of 22 genes are closest to those of type C strains. Consistent with findings of UGT-type genetic features in the chromosome, the QH111L plasmid appears to be intermediate between UGT and classical ocular plasmids due to the existence of UGT-type SNPs in the QH111L plasmid. Moreover, the QH111L strain has a unique evolutionarily older cytotoxin region compared to cytotoxin regions of other C. trachomatis strains. The genome analyses suggest that the QH111L strain is derived from

Hydro-meteorological processes on the Qinghai - Tibet Plateau observed from space

NASA Astrophysics Data System (ADS)

Menenti, Massimo; Colin, Jerome; Jia, Li; D'Urso, Guido; Foken, Thomas; Immerzeel, Walter; Jha, Ramakar; Liu, Qinhuo; Liu, Changming; Ma, Yaoming; Sobrino, Jose Antonio; Yan, Guangjian; Pelgrum, Henk; Porcu, Federico; Wang, Jian; Wang, Jiemin; Shen, Xueshun; Su, Zhongbo; Ueno, Kenichi

2014-05-01

The Qinghai - Tibet Plateau is characterized by a significant intra-annual variability and spatial heterogeneity of surface conditions. Snow and vegetation cover, albedo, surface temperature and wetness change very significantly during the year and from place to place. The influence of temporal changes on convective events and the onset of the monsoon has been documented by ground based measurements of land - atmosphere exchanges of heat and water. The state of the land surface over the entire Plateau can be determined by space observation of surface albedo, temperature, snow and vegetation cover and soil moisture. Fully integrated use of satellite and ground observations is necessary to support water resources management in SE Asia and to clarify the roles of the interactions between the land surface and the atmosphere over the Tibetan Plateau in the Asian monsoon system. New or significantly improved algorithms have been developed and evaluated against ground measurements. Variables retrieved include land surface properties, rain rate, aerosol optical depth, water vapour, snow cover and water equivalent, soil moisture and lake level. The three years time series of gap-free daily and hourly evaporation derived from geostationary data collected by the FY-2D satellite was a major achievement. The hydrologic modeling system has been implemented and applied to the Qinghai Tibet Plateau and the headwaters of the major rivers in South and East Asia. Case studies on response of atmospheric circulation and specifically of convective activity to land surface conditions have been completed and the controlling land surface conditions and processes have been documented. Two new drought indicators have been developed: Normalized Temperature Anomaly Index (NTAI) and Normalized Vegetation Anomaly Index (NVAI). Case study in China and India showed that these indicators capture effectively drought severity and evolution. A new method has been developed for monitoring and early

Historical Records of Mercury Stable Isotopes in Sediments of Tibetan Lakes

NASA Astrophysics Data System (ADS)

Yin, Runsheng; Feng, Xinbin; Hurley, James P.; Krabbenhoft, David P.; Lepak, Ryan F.; Kang, Shichang; Yang, Handong; Li, Xiangdong

2016-03-01

The Tibetan Plateau (TP), known as the “Third Pole”, is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in the globe leads to environmental changes, which may affect the loading, transport and deposition of Hg in the environment. However, the deposition history and geochemical cycling of Hg in the TP is still uncertain. Our records of Hg and Hg isotopes in sediment profiles of the two largest lakes in the TP, Lake Qinghai and Nam Co, show increased Hg influx since last century, with the maximum Hg influx enrichment ratios of 5.4 and 3.5 in Lake Qinghai and Nam Co, respectively. Shifts in negative δ 202Hg in Lake Qinghai (-4.55 to -3.15‰) and Nam Co (-5.04 to -2.16‰) indicate increased atmospheric Hg deposition through rainfall, vegetation and runoff of soils. Mass independent fractionation of both even-Hg (∆ 200Hg: +0.05 to +0.10‰) and odd-Hg (∆ 199Hg: +0.12 to +0.31‰) isotopes were observed. Positive Δ 200Hg suggest high proportion of precipitation-derived Hg in the TP, whereas the positive Δ 199Hg results from Hg(II) photo-reduction. Both lakes show increasing Δ 199Hg since the 1900 s, and we conclude that with the decrease of ice duration, Hg(II) photo-reduction may have been accelerated in these TP lakes.

Historical Records of Mercury Stable Isotopes in Sediments of Tibetan Lakes.

PubMed

Yin, Runsheng; Feng, Xinbin; Hurley, James P; Krabbenhoft, David P; Lepak, Ryan F; Kang, Shichang; Yang, Handong; Li, Xiangdong

2016-03-21

The Tibetan Plateau (TP), known as the "Third Pole", is a critical zone for atmospheric mercury (Hg) deposition. Increasing anthropogenic activities in the globe leads to environmental changes, which may affect the loading, transport and deposition of Hg in the environment. However, the deposition history and geochemical cycling of Hg in the TP is still uncertain. Our records of Hg and Hg isotopes in sediment profiles of the two largest lakes in the TP, Lake Qinghai and Nam Co, show increased Hg influx since last century, with the maximum Hg influx enrichment ratios of 5.4 and 3.5 in Lake Qinghai and Nam Co, respectively. Shifts in negative δ (202)Hg in Lake Qinghai (-4.55 to -3.15‰) and Nam Co (-5.04 to -2.16‰) indicate increased atmospheric Hg deposition through rainfall, vegetation and runoff of soils. Mass independent fractionation of both even-Hg (∆ (200)Hg: +0.05 to +0.10‰) and odd-Hg (∆ (199)Hg: +0.12 to +0.31‰) isotopes were observed. Positive Δ (200)Hg suggest high proportion of precipitation-derived Hg in the TP, whereas the positive Δ (199)Hg results from Hg(II) photo-reduction. Both lakes show increasing Δ (199)Hg since the 1900 s, and we conclude that with the decrease of ice duration, Hg(II) photo-reduction may have been accelerated in these TP lakes.

A new species of the genus Discolaimus Cobb, 1913 (Nematoda: Dorylaimida: Qudsianematidae) from Qinghai, China.

PubMed

Wu, Wen-Jia; Yan, Lin; Xu, Chun-Ling; Wang, Ke; Jin, Sheng-Ying; Xie, Hui

2016-03-07

A new species of the family Qudsianematidae Jairajpuri, 1965 collected from soil from Qinghai Province, China is described as Discolaimus anemaqen n. sp. It is mainly characterized by having a disc-like lip region with six labial sectors separated by six Y-shaped radial grooves; amphid fovea an inverted-stirrup shape; odontostyle aperture 53-59% of its length; anterior part of pharynx with two swellings, basal part expanded gradually with a sheath of tissue visible ventrally and at the base; no groups of large cells observed in cardiac region; female genital system amphidelphic; tail dorsally convex, conoid, with flat ventral side and bluntly rounded terminus, and males not found. The new species is close to D. major Thorne, 1939, D. similis Thorne, 1939 and D. silvicolus Sauer & Annells, 1985 in most measurements, but can be differentiated from them by lip morphology, pharynx structure, body size, and tail shape. A key to the species of Discolaimus is also provided.

Quantitative precipitation estimates for the northeastern Qinghai-Tibetan Plateau over the last 18,000 years

NASA Astrophysics Data System (ADS)

Li, Jianyong; Dodson, John; Yan, Hong; Cheng, Bo; Zhang, Xiaojian; Xu, Qinghai; Ni, Jian; Lu, Fengyan

2017-05-01

Quantitative information regarding the long-term variability of precipitation and vegetation during the period covering both the Late Glacial and the Holocene on the Qinghai-Tibetan Plateau (QTP) is scarce. Herein, we provide new and numerical reconstructions for annual mean precipitation (PANN) and vegetation history over the last 18,000 years using high-resolution pollen data from Lakes Dalianhai and Qinghai on the northeastern QTP. Hitherto, five calibration techniques including weighted averaging, weighted average-partial least squares regression, modern analogue technique, locally weighted weighted averaging regression, and maximum likelihood were first employed to construct robust inference models and to produce reliable PANN estimates on the QTP. The biomization method was applied for reconstructing the vegetation dynamics. The study area was dominated by steppe and characterized with a highly variable, relatively dry climate at 18,000-11,000 cal years B.P. PANN increased since the early Holocene, obtained a maximum at 8000-3000 cal years B.P. with coniferous-temperate mixed forest as the dominant biome, and thereafter declined to present. The PANN reconstructions are broadly consistent with other proxy-based paleoclimatic records from the northeastern QTP and the northern region of monsoonal China. The possible mechanisms behind the precipitation changes may be tentatively attributed to the internal feedback processes of higher latitude (e.g., North Atlantic) and lower latitude (e.g., subtropical monsoon) competing climatic regimes, which are primarily modulated by solar energy output as the external driving force. These findings may provide important insights into understanding the future Asian precipitation dynamics under the projected global warming.

Elemental carbon and polycyclic aromatic compounds in a 150-year sediment core from Lake Qinghai, Tibetan Plateau, China: influence of regional and local sources and transport pathways.

PubMed

Han, Y M; Wei, C; Bandowe, B A M; Wilcke, W; Cao, J J; Xu, B Q; Gao, S P; Tie, X X; Li, G H; Jin, Z D; An, Z S

2015-04-07

Elemental carbon (EC) and polycyclic aromatic compounds (PACs) are potential proxies for the reconstruction of change in human activities and the origin of air masses in historic times. In this study, the historic deposition of char and soot (the two subtypes of EC) and PACs in a 150-year sediment core from different topographic subbasins of Lake Qinghai on the Qinghai Tibetan Plateau (QTP) were reconstructed. The objective was to explore how the variations in the concentrations of EC and PACs, in the ratios of char to soot and of oxygenated polycyclic aromatic hydrocarbons (OPAHs) to parent PAHs, and in the composition of the PAC mixtures reflect historical changes in climate and human activity and the origin of air masses arriving at the QTP. The deposition fluxes of soot in the different subbasins were similar, averaging 0.18 (range of 0.15-0.25) and 0.16 (0.13-0.23) g m(-2) year(-1), respectively, but they varied for char (averaging 0.11 and 0.22 g m(-2) year(-1), respectively), suggesting ubiquitous atmospheric deposition of soot and local river inputs of char. The different vertical distributions of the char/soot ratios in the different subbasins can be interpreted in terms of the different transport mechanisms of char and soot. An abrupt increase in soot concentrations since 1980 coincides with results from the QTP ice cores that were interpreted to be indicative of soot transport from South Asia. Similar concentration patterns of PAHs with soot and 9,10-anthraquinone/anthracene (9,10-AQ/ANT) ratios all >2.0 suggest regional PAC sources. Increasing PAH/soot ratios and decreasing 9,10-AQ/ANT ratios since the beginning of the 1970s indicate increasing local emissions. The historical trends of these diagnostic ratios indicate an increase in the fossil-fuel contribution since the beginning of the 1970s. The increase of perylene concentrations with increasing core depth and the ratio of perylene to its penta-aromatic isomers indicate that perylene originates

Analysis on development situation and tendency of international Qinghai-Tibet Plateau studies

NASA Astrophysics Data System (ADS)

Wang, X.

2015-12-01

Qinghai-Tibet Plateau is one of the hotspots of the international earth science studies. The relative research papers have proliferated especially since 21st century. By using the the latest bibliometric indicators, the statistical analysis of the quantities and qualities was carried out for the Qinghai-Tibet Plateau literature indexed by SCIE during 1900 and 2012. It focused on the published years, journals, countries, cities, research institutes, international cooperation, and subjects. Some statistical results were displayed and deeply analyzed by using the tools of mapping knowledge domain (MKD) and geographic information system (GIS). The results of the Bibliometric analysis indicate that the publication and citation of QTP researches have a jump after entering the 21st century. China, USA, India, Canada and France are the main coutries engaged in the Qinghai-Tibet Plateau studies. Knowledge mapping results show that USA, UK and France have longer academic influential power of QTP researches, which indicates that these countries begin to study QTP early and the papers have longer permanent impacts. On the other hand, China, India and Japan have higher academic influential power in recent years, which indicate that these countries have more publications and higher impacts recently. The disciplines of QTP researches mainly focus on the geology, geochemistry &geophysics, environmental sciences &ecology, and so on. The spatial analysis indicates that the differences of the disciplines are emphasized by different countries. The above analysis results is hoped to integrate the new knowledge and reveal the development tendency of the QTP researches.

Population Differentiations and Phylogenetic Analysis of Tibet and Qinghai Tibetan Groups Based on 30 InDel Loci.

PubMed

Guo, Yuxin; Shen, Chunmei; Meng, Haotian; Dong, Qian; Kong, Tingting; Yang, Chunhua; Wang, Hongdan; Jin, Rui; Zhu, Bofeng

2016-12-01

In recent years, Insertion/Deletion (InDel) polymorphisms have become a hot area of forensic research. In this study, 30 InDel loci were selected to investigate the genetic polymorphisms of Tibetan groups, which are from Tibet Autonomous Region and Qinghai province of China, and explore the genetic relationships between Tibetan groups and other groups. Allele frequencies of the 30 InDel loci ranged from 0.1219 (HLD111) to 0.5609 (HLD57) in the Tibet Tibetan group and 0.1639 (HLD118) to 0.5655 (HLD124) in the Qinghai Tibetan group. The combined power of discrimination, matching probability, and power of exclusion were 0.999999999986, 0.999999988, and 0.9913 in the Tibet Tibetan group, respectively, and 0.99999999999204, 0.9999999796, and 0.9862 in the Qinghai Tibetan group. The results of principal component analysis, phylogenetic tree, and population structure demonstrated that the four Tibetan groups (Tibetan1, Tibetan2, Tibet, and Qinghai Tibetan groups) clustered together and had relatively close genetic relationships with nine Asian groups and then European and Amerindian groups.

Molecular identification of Echinococcus species from eastern and southern Qinghai, China, based on the mitochondrial cox1 gene.

PubMed

Ma, Junying; Wang, Hu; Lin, Gonghua; Craig, Philip S; Ito, Akira; Cai, Zhenyuan; Zhang, Tongzuo; Han, Xiumin; Ma, Xiao; Zhang, Jingxiao; Liu, Yufang; Zhao, Yanmei; Wang, Yongshun

2012-07-01

The Qinghai-Tibetan Plateau (QTP, in western China), which is the largest and highest plateau on Earth, is a highly epidemic region for Echinococcus spp. We collected 70 Echinococcus samples from humans, dogs, sheep, yaks, plateau pikas, and voles in eastern and southern Qinghai and genotyped them using the mitochondrial DNA marker cytochrome oxidase subunit I gene and maximum parsimony and Bayesian reconstruction methods. Based on the 792-bp sequence matrix, we recorded 124 variable sites, of which, 115 were parsimony-informative. Thirty-four haplotypes (H1-H34) were detected, of which H1-H15, H16-H17, and H18-H34 belonged to Echinococcus shiquicus, Echinococcus multilocularis, and Echinococcus granulosus, respectively. Within 26 human isolates, three were identified as E. multilocularis and 23 were E. granulosus. We also detected a dual infection case in a dog with E. multilocularis and E. granulosus. The intraspecific haplotype (Hd ± SD) and nucleotide (Nd ± SD) diversity of E. shiquicus (0.947 ± 0.021; 0.00441 ± 0.00062) was higher than that for E. granulosus (0.896 ± 0.038; 0.00221 ± 0.00031) and E. multilocularis (0.286 ± 0.196; 0.00036 ± 0.00025). Moreover, the haplotype network of E. shiquicus showed a radial feature rather than a divergent feature in a previous study, indicating this species in the QTP has also evolved with bottleneck effects.

Prevalence and molecular characterization of Cryptosporidium spp. and Giardia duodenalis in 1-2-month-old highland yaks in Qinghai Province, China.

PubMed

Wang, Geping; Wang, Guanghua; Li, Xiuping; Zhang, Xueyong; Karanis, Gabriele; Jian, Yingna; Ma, Liqing; Karanis, Panagiotis

2018-06-01

Cryptosporidium and Giardia are ubiquitous parasites that infect humans and animals. Few reports are available on the prevalence of these two protozoan parasites in yaks (Bos grunniens). In this study, 344 faecal samples were collected from yaks with diarrhoea in the Chenduo and Nangqian counties of Qinghai Province, China. Cryptosporidium spp. and Giardia duodenalis were detected by light and immunofluorescence microscopy and nested PCR (nPCR). Fifteen samples were positive (4.5%) by Kinyoun staining, 40 (11.6%) samples were positive by immunofluorescence test (IFT), and 39 (11.3%) samples were positive by nPCR for Cryptosporidium spp., Cryptosporidium bovis (11/39, 28.2%) was the most prevalent species, followed by C. ryanae (6/39, 15.4%), C. andersoni (5/39, 12.8%), C. struthionis (5/39, 12.8%), C. parvum (5/39, 12.8%), C. hominis (4/39, 10.3%) and C. canis (3/39, 7.7%). Thirteen out of 344 (3.8%) samples were positive for Giardia by simple microscopy, 20 (5.8%) by IFT and 18 samples (5.2%) yak faecal samples were Giardia positive by nPCR. Two G. duodenalis assemblages (B, E) were detected in this study. Nine positive samples for G. duodenalis assemblage E were from the towns of Xiewu (8/9, 4.9%) and Xiangda (1/9, 1.3%), and nine positive samples (9/9, 8.5%) for G. duodenalis assemblage B were from the town of Zhenqin. This report provides information about infection with Cryptosporidium species and G. duodenalis assemblages in domesticated 1-2-month-old highland yaks living in the Qinghai-Tibet Plateau region of China.

[Molecular epidemiological study of measles viruses isolated in Qinghai Province during 2000-2011].

PubMed

Fan, Li-Xia; Ba, Zhuo-Ma; Zhao, Sheng-Cang; Yi, Hu; Jiang, Shuang-Ying; Zhang, Yan; Wang, Hui-Ling; Xu, Wen-Bo

2013-08-01

To carry out the molecular epidemiological study of the wild-type measles virus isolated in Qinghai Province during 2000-2011, and provide a scientific basis for the measles elimination. Measles viruses were isolated using B95a cell line or Vero/SLAM cell line from throat swabs collected from suspected measles cases during measles outbreak and sporadic in 6 prefectures during 2000-2011. The fragment of 696 nucleotides of N gene carboxy terminal was amplified by using RT-PCR methods. The PCR products were sequenced and analyzed. The phylogenetic tree was conducted with the viruses isolated in viruses from other province. Total 19 measles viruses were isolated during 2000-2011 in Qinghai province and all belong to genotype H1a. The results of phylogenetic tree showed that viruses in 2000-2005 and in 2009-2011 were distributed in two different lineages, and it revealed that these strains belonged to at least 2 viral transmission chains and the viruses circulated during 2000-2005 were not detected after 2005. Genotype H1a was the predominant genotype circulated in Qinghai province during 2000-2011. Qinghai measles virus strains had not evolved independently, but coevolved with the measles virus strains in other provinces in mainland China. The variation of important amino acid sites of measles virus should be continuous monitored and provide the scientific strategy for the measles elimination.

Effects of the Qinghai-Tibet Railway on the Landscape Genetics of the Endangered Przewalski's Gazelle (Procapra przewalskii).

PubMed

Yu, He; Song, Shiya; Liu, Jiazi; Li, Sheng; Zhang, Lu; Wang, Dajun; Luo, Shu-Jin

2017-12-21

The Przewalski's gazelle (Procapra przewalskii) is one of the most endangered ungulates in the world, with fewer than 2,000 individuals surviving in nine habitat fragments on the Qinghai-Tibet Plateau and isolated by human settlements and infrastructure. In particular, the Qinghai-Tibet railway, which crosses the largest part of the gazelle's distribution, remains a major concern because of its potential to intensify landscape genetic differentiation. Here, using mtDNA sequencing and microsatellite genotyping to analyze 275 Przewalski's gazelle samples collected throughout the range, we observed low level of genetic diversity (mtDNA π = 0.0033) and strong phylogeographic structure. Overall, the nine patches of gazelles can be further clustered into five populations, with a strong division between the eastern vs. western side of Qinghai Lake. Our study provides the first evidence of the genetic divergence between the Haergai North and Haergai South gazelle populations, corresponding to the recent construction of a wired enclosure along the Qinghai-Tibet railway less than ten years ago, an equivalent of five generations. Well-designed wildlife corridors across the railway along with long-term monitoring of the anthropogenic effects are therefore recommended to alleviate further habitat fragmentation and loss of genetic diversity in Przewalski's gazelle.

Remote sensing of severe convective storms over Qinghai-Xizang Plateau

NASA Technical Reports Server (NTRS)

Hung, R. J.; Liu, J. M.; Tsao, D. Y.; Smith, R. E.

1984-01-01

The American satellite, GOES-1 was moved to the Indian Ocean at 58 deg E during the First GARP Global Experiment (FGGE). The Qinghai-Xizang Plateau significantly affects the initiation and development of heavy rainfall and severe storms in China, just as the Rocky Mountains influence the local storms in the United States. Satelite remote sensing of short-lived, meso-scale convective storms is particularly important for covering a huge area of a high elevation with a low population density, such as the Qinghai-Xizang Plateau. Results of this study show that a high growth rate of the convective clouds, followed by a rapid collapse of the cloud top, is associated with heavy rainfall in the area. The tops of the convective clouds developed over the Plateau lie between the altitudes of the two tropopauses, while the tops of convective clouds associated with severe storms in the United States usually extend much above the tropopause.

Spatial distribution of Qinghai spruce forests and the thresholds of influencing factors in a small catchment, Qilian Mountains, northwest China.

PubMed

Yang, Wenjuan; Wang, Yanhui; Wang, Shunli; Webb, Ashley A; Yu, Pengtao; Liu, Xiande; Zhang, Xuelong

2017-07-17

Forest restoration in dryland mountainous areas is extremely difficult due to dry climate, complex topography and accelerating climate change. Thus, exact identification of suitable sites is required. This study at a small watershed of Qilian Mountains, Northwest China, aimed to determine the important factors and their thresholds limiting the spatial distribution of forests of Qinghai spruce (Picea crassifolia), a locally dominant tree species. The watershed was divided into 342 spatial units. Their location, terrain and vegetation characteristics were recorded. Statistical analysis showed that the potential distribution area of Qinghai spruce forests is within an ellipse with the axes of elevation (from 2673.6 to 3202.2 m a.s.l.) and slope aspect (from -162.1° to 75.1° deviated from North). Within this ellipse, the forested sites have a soil thickness ≥40 cm, and slope positions of lower-slope, lower- or middle-slope, anywhere if the elevation is <2800, 2800-2900, >2900 m a.s.l, respectively. The corresponding mean annual air temperature at upper elevation boundary is -2.69 °C, while the mean annual precipitation at lower elevation boundary is 374 (331) mm within the small watershed (study area). The high prediction accuracy using these 4 factors can help to identify suitable sites and increase the success of afforestation.

Dramatic and long-term lake level changes in the Qinghai-Tibet Plateau from Cryosat-2 altimeter: validation and augmentation by results from repeat altimeter missions and satellite imagery

NASA Astrophysics Data System (ADS)

Hwang, Cheinway; Huang, YongRuei; Cheng, Ys; Shen, WenBin; Pan, Yuanjin

2017-04-01

The mean elevation of the Qinghai-Tibet Plateau (QTP) exceeds 4000 m. Lake levels in the QTP are less affected by human activities than elsewhere, and may better reflect the state of contemporary climate change. Here ground-based lake level measurements are rare. Repeat altimeter missions, particularly those from the TOPEX and ERS series of altimetry, have provided long-term lake level observations in the QTP, but their large cross-track distances allow only few lakes to be monitored. In contrast, the Cryosat-2 altimeter, equipped with the new sensor SIRAL (interferometric/ synthetic aperture radar altimeter), provides a much better ranging accuracy and a finer spatial coverage than these repeated missions, and can detect water level changes over a large number of lakes in the QTP. In this study, Cryosat-2 data are used to determine lake level changes over 75˚E-100˚E and 28˚N-37.5˚N, where Cryosat-2 covers 60 lakes and SARAL/ AltiKa covers 32 lakes from 2013 to 2016. Over a lake, Cryosat-2 in different cycles can pass through different spots of the lake, making the numbers of observations non-uniform and requiring corrections for lake slopes. Four cases are investigated to cope with these situations: (1) neglecting inconsistency in data volume and lake slopes (2) considering data volume, (3) considering lake slopes only, and (4) considering both data volume and lake slopes. The CRYOSAT-2 result is then compared with the result from the SARAL to determine the best case. Because Cryosat-2 is available from 2010 to 2016, Jason-2 data are used to fill gaps between the time series of Cryosat-2 and ICESat (2003-2009) to obtain >10 years of lake level series. The Cryosat-2 result shows dramatic lake level rises in Lakes Kusai, Zhuoaihu and Salt in 2011 caused by floods. Landsat satellite imagery assists the determination and interpretation of such rises.

Microplastics in surface waters of Dongting Lake and Hong Lake, China.

PubMed

Wang, Wenfeng; Yuan, Wenke; Chen, Yuling; Wang, Jun

2018-08-15

Microplastics pollution is an environmental issue of increasing concern. Much work has been done on the microplastics pollution in the marine environments. Although freshwaters are potential sources and transport pathways of plastic debris to the oceans, there is a lack of knowledge regarding the presence of microplastics in freshwater systems, especially in China, the world's largest producer of plastics. This study investigated the occurrence and properties of microplastics in surface waters of two important lakes in the middle reaches of the Yangtze River. The concentration ranges of microplastics in Dongting Lake and Hong Lake were 900-2800 and 1250-4650n/m 3 , respectively. Fiber was the dominant shape. Colored items occupied the majority. Particles with a size of <330μm comprised >20% of total microplastics collected in both lakes. Most of the selected particles were identified as plastics, with polyethylene (PE) and polypropylene (PP) being the major components. This study can provide valuable reference for better understanding the microplastics pollution in inland freshwater ecosystems. Copyright © 2018 Elsevier B.V. All rights reserved.

Radiocarbon dating of individual lignin phenols: a new approach for establishing chronology of late quaternary lake sediments.

PubMed

Hou, Juzhi; Huang, Yongsong; Brodsky, Corynn; Alexandre, Marcelo R; McNichol, Ann P; King, John W; Hu, Feng Sheng; Shen, Ji

2010-09-01

The reliability of chronology is a prerequisite for meaningful paleoclimate reconstructions from sedimentary archives. The conventional approach of radiocarbon dating bulk organic carbon in lake sediments is often hampered by the old carbon effect, i.e., the assimilation of ancient dissolved inorganic carbon (DIC) derived from carbonate bedrocks or other sources. Therefore, radiocarbon dating is ideally performed on organic compounds derived from land plants that use atmospheric CO(2) and rapidly delivered to sediments. We demonstrate that lignin phenols isolated from lake sediments using reversed phase high performance liquid chromatography (HPLC) can serve as effective (14)C dating materials for establishing chronology during the late Quaternary. We developed a procedure to purify lignin phenols, building upon a published method. By isolating lignin from standard wood reference substances, we show that our method yields pure lignin phenols and consistent ages as the consensus ages and that our procedure does not introduce radiocarbon contamination. We further demonstrate that lignin phenol ages are compatible with varve counted and macrofossil dated sediment horizons in Steel Lake and Fayetteville Green Lake. Applying the new method to lake sediment cores from Lake Qinghai demonstrates that lignin phenol ages in Lake Qinghai are consistently younger than bulk total organic carbon (TOC) ages which are contaminated by old carbon effect. We also show that the age offset between lignin and bulk organic carbon differs at different Lake Qinghai sedimentary horizons, suggesting a variable hard water effect at different times and that a uniform age correction throughout the core is inappropriate.

Microbial community structure and diversity within hypersaline Keke Salt Lake environments.

PubMed

Han, Rui; Zhang, Xin; Liu, Jing; Long, Qifu; Chen, Laisheng; Liu, Deli; Zhu, Derui

2017-11-01

Keke Salt Lake is located in the Qaidamu Basin of China. It is a unique magnesium sulfate-subtype hypersaline lake that exhibits a halite domain ecosystem, yet its microbial diversity has remained unstudied. Here, the microbial community structure and diversity was investigated via high-throughput sequencing of the V3-V5 regions of 16S rRNA genes. A high diversity of operational taxonomic units was detected for Bacteria and Archaea (734 and 747, respectively), comprising 21 phyla, 43 classes, and 201 genera of Bacteria and 4 phyla, 4 classes, and 39 genera of Archaea. Salt-saturated samples were dominated by the bacterial genera Bacillus (51.52%-58.35% relative abundance), Lactococcus (9.52%-10.51%), and Oceanobacillus (8.82%-9.88%) within the Firmicutes phylum (74.81%-80.99%), contrasting with other hypersaline lakes. The dominant Archaea belonged to the Halobacteriaceae family, and in particular, the genera (with an abundance of >10% of communities) Halonotius, Halorubellus, Halapricum, Halorubrum, and Natronomonas. Additionally, we report the presence of Nanohaloarchaeota and Woesearchaeota in Qinghai-Tibet Plateau lakes, which has not been previously documented. Total salinity (especially Mg 2+ , Cl - , Na + , and K + ) mostly correlated with taxonomic distribution across samples. These results expand our understanding of microbial resource utilization within hypersaline lakes and the potential adaptations of dominant microorganisms that allow them to inhabit such environments.

Carbon and energy fluxes from China's largest freshwater lake

NASA Astrophysics Data System (ADS)

Gan, G.; LIU, Y.

2017-12-01

Carbon and energy fluxes between lakes and the atmosphere are important aspects of hydrology, limnology, and ecology studies. China's largest freshwater lake, the Poyang lake experiences tremendous water-land transitions periodically throughout the year, which provides natural experimental settings for the study of carbon and energy fluxes. In this study, we use the eddy covariance technique to explore the seasonal and diurnal variation patterns of sensible and latent heat fluxes of Poyang lake during its high-water and low-water periods, when the lake is covered by water and mudflat, respectively. We also determine the annual NEE of Poyang lake and the variations of NEE's components: Gross Primary Productivity (GPP) and Ecosystem Respiration (Re). Controlling factors of seasonal and diurnal variations of carbon and energy fluxes are analyzed, and land cover impacts on the variation patterns are also studied. Finally, the coupling between the carbon and energy fluxes are analyzed under different atmospheric, boundary stability and land cover conditions.

Polycyclic aromatic hydrocarbons and organochlorine pesticides in surface soils from the Qinghai-Tibetan plateau.

PubMed

Tao, Shu; Wang, Wentao; Liu, Wenxin; Zuo, Qian; Wang, Xilong; Wang, Rong; Wang, Bin; Shen, Guofeng; Yang, Yuanhe; He, Jin-shen

2011-01-01

Eighty eight surface soil samples were collected from the Qinghai-Tibetan Plateau (QTP) for determination of polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides (OCPs), including dichlorodiphenyltrichloroethane and metabolites (DDXs) and hexachlorocyclohexane isomers (HCHs). The measured concentrations were 51.8 ± 38.5 ng g(-1), 0.329 ± 0.818 ng g(-1), and 0.467 ± 0.741 ng g(-1) as means and standard deviations of PAHs, DDXs, and HCHs, respectively, which were 1-2 orders of magnitude lower than those reported for eastern China. Significant differences were also revealed among four sub-areas within QTP. PAHs detected in the samples from the remote sub-areas of T'ang-ku-la/Hoh Xil Mountains and along the Qinghai-Tibet highway in the west and northwest of QTP were 1 order of magnitude lower than those from Lhasa and east Qinghai. The differences in soil OCPs among the sub-areas were 2-7 times. Soil PAHs were significantly correlated with emission density and soil organic carbon content (SOC), while OCPs were correlated significantly with the population density and SOC. Based on the calculated backward air mass trajectories and geographical distributions of emission and population, it was revealed that PAHs and OCPs accumulated in the soils in the west and northwest QTP were primarily from long-range transport and may represent the background levels of East Asia. This part of QTP can also serve as an important receptor area for regional or even global long-range transport study. The elevated concentrations of PAHs and OCPs in Lhasa and east Qinghai were mainly from local sources, while PAHs from adjacent Lanzhou area also contributed considerably to the accumulation of PAHs in east Qinghai.

Two reassortant types of highly pathogenic H5N8 avian influenza virus from wild birds in Central China in 2016.

PubMed

Ma, Liping; Jin, Tao; Wang, Hanzhong; Liu, Haizhou; Wang, Runkun; Li, Yong; Yang, Guoxiang; Xiong, Yanping; Chen, Jing; Zhang, Jun; Chen, Guang; Li, Wei; Liu, Di; Lin, Peng; Huang, Yueying; Gao, George F; Chen, Quanjiao

2018-02-07

Since 2016, the highly pathogenic avian influenza H5N8 virus has emerged in the Central Asian flyway and Europe, causing massive deaths in poultry and wild birds. In this study, we isolated and identified three H5N8 viruses from swan goose and black swans in Hubei province during the 2016/2017 winter season. Whole-genome sequencing and phylogenetic analysis revealed that the three viruses clustered into a group of H5N8 viruses from Qinghai Lake and Europe. A novel reassortment virus from swan goose was distinguished from that of black swans, in that its PA and NP genes were distinct from those of Qinghai Lake viruses. Molecular dating revealed that the ancestral strain of these H5N8 viruses emerged around July 2015. From sequence comparison, we discovered eight amino acid substitutions in HA and NA during the adaption process from poultry to wild birds. The three viruses were isolated from wild birds in the East Asian-Australasian flyway; however, the viral genomes were similar to H5N8 viruses circulating along the Central Asian flyway. From these data, we conclude that wetlands and lakes in Central China may play a key role in disseminating H5N8 viruses between the East Asian-Australasian and Central Asian flyways.

A drinking water crisis in Lake Taihu, China: linkage to climatic variability and lake management.

PubMed

Qin, Boqiang; Zhu, Guangwei; Gao, Guang; Zhang, Yunlin; Li, Wei; Paerl, Hans W; Carmichael, Wayne W

2010-01-01

In late May, 2007, a drinking water crisis took place in Wuxi, Jiangsu Province, China, following a massive bloom of the toxin producing cyanobacteria Microcystis spp. in Lake Taihu, China's third largest freshwater lake. Taihu was the city's sole water supply, leaving approximately two million people without drinking water for at least a week. This cyanobacterial bloom event began two months earlier than previously documented for Microcystis blooms in Taihu. This was attributed to an unusually warm spring. The prevailing wind direction during this period caused the bloom to accumulate at the shoreline near the intake of the water plant. Water was diverted from the nearby Yangtze River in an effort to flush the lake of the bloom. However, this management action was counterproductive, because it produced a current which transported the bloom into the intake, exacerbating the drinking water contamination problem. The severity of this microcystin toxin containing bloom and the ensuing drinking water crisis were attributable to excessive nutrient enrichment; however, a multi-annual warming trend extended the bloom period and amplified its severity, and this was made worse by unanticipated negative impacts of water management. Long-term management must therefore consider both the human and climatic factors controlling these blooms and their impacts on water supply in this and other large lakes threatened by accelerating eutrophication.

Eco-Environment Status Evaluation and Change Analysis of Qinghai Based on National Geographic Conditions Census Data

NASA Astrophysics Data System (ADS)

Zheng, M.; Zhu, M.; Wang, Y.; Xu, C.; Yang, H.

2018-04-01

As the headstream of the Yellow River, the Yangtze River and the Lantsang River, located in the hinterland of Qinghai-Tibet Plateau, Qinghai province is hugely significant for ecosystem as well as for ecological security and sustainable development in China. With the accomplishment of the first national geographic condition census, the frequent monitoring has begun. The classification indicators of the census and monitoring data are highly correlated with Technical Criterion for Ecosystem Status Evaluation released by Ministry of Environmental Protection in 2015. Based on three years' geographic conditions data (2014-2016), Landsat-8 images and thematic data (water resource, pollution emissions, meteorological data, soil erosion, etc.), a multi-years and high-precision eco-environment status evaluation and spatiotemporal change analysis of Qinghai province has been researched on the basis of Technical Criterion for Ecosystem Status Evaluation in this paper. Unlike the evaluation implemented by environmental protection department, the evaluation unit in this paper is town rather than county. The evaluation result shows that the eco-environment status in Qinghai is generally in a fine condition, and has significant regional differences. The eco-environment status evaluation based on national geographic conditions census and monitoring data can improve both the time and space precision. The eco-environment status with high space precise and multi-indices is a key basis for environment protection decision-making.

Evaluation of the Township Proper Carrying Capacity over Qinghai-Tibet plateau by CASA model

NASA Astrophysics Data System (ADS)

Wu, Chengyong; Cao, Guangchao; Xue, Huaju; Jiang, Gang; Wang, Qi; Yuan, Jie; Chen, Kelong

2018-01-01

The existing study of proper carrying capacity (PCC) has mostly focused on province or county administrative units, which can only macroscopically master the quantitative characteristics of PCC, but could not effectively take some animal husbandry management measures that are pertinent and operational. At town-scale, this paper used CASA model to estimate the PCC in Mongolian Autonomous County of Henan, Qinghai province, China,with serious grassland degeneration that mainly caused by overgrazing. The results showed that the PCC throughout the County was 950,417 sheep unit. For the township, the PCC of Saierlong and Duosong were the largest (247,100 sheep unit) and the smallest (82,016 sheep unit) respectively. This study will provide reference data for developing sustainable development of town-scale pasture policies and also will help to evaluate the health status of the alpine grassland ecosystem on Qinghai-Tibet plateau.

Application of the ORCHIDEE global vegetation model to evaluate biomass and soil carbon stocks of Qinghai-Tibetan grasslands

NASA Astrophysics Data System (ADS)

Tan, Kun; Ciais, Philippe; Piao, Shilong; Wu, Xiaopu; Tang, Yanhong; Vuichard, Nicolas; Liang, Shuang; Fang, Jingyun

2010-03-01

The cold grasslands of the Qinghai-Tibetan Plateau form a globally significant biome, which represents 6% of the world's grasslands and 44% of China's grasslands. Yet little is known about carbon cycling in this biome. In this study, we calibrated and applied a process-based ecosystem model called Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) to estimate the C fluxes and stocks of these grasslands. First, the parameterizations of ORCHIDEE were improved and calibrated against multiple time-scale and spatial-scale observations of (1) eddy-covariance fluxes of CO2 above one alpine meadow site; (2) soil temperature collocated with 30 meteorological stations; (3) satellite leaf area index (LAI) data collocated with the meteorological stations; and (4) soil organic carbon (SOC) density profiles from China's Second National Soil Survey. The extensive SOC survey data were used to extrapolate local fluxes to the entire grassland biome. After calibration, we show that ORCHIDEE can successfully capture the seasonal variation of net ecosystem exchange (NEE), as well as the LAI and SOC spatial distribution. We applied the calibrated model to estimate 0.3 Pg C yr-1 (1 Pg = 1015 g) of total annual net primary productivity (NPP), 0.4 Pg C of vegetation total biomass (aboveground and belowground), and 12 Pg C of SOC stocks for Qinghai-Tibetan grasslands covering an area of 1.4 × 106 km2. The mean annual NPP, vegetation biomass, and soil carbon stocks decrease from the southeast to the northwest, along with precipitation gradients. Our results also suggest that in response to an increase of temperature by 2°C, approximately 10% of current SOC stocks in Qinghai-Tibetan grasslands could be lost, even though NPP increases by about 9%. This result implies that Qinghai-Tibetan grasslands may be a vulnerable component of the terrestrial carbon cycle to future climate warming.

Chemical characterization of dissolved organic matter in an alpine stream from thawing and collapsing permafrost to Qinghai Lake

NASA Astrophysics Data System (ADS)

Wang, Y.; Xu, Y.

2016-12-01

The Tibetan Plateau is the world's largest and highest plateau, approximately two thirds of which is covered by permafrost. Due to recent climate warming, large organic carbon stored in the permafrost is thawing and becomes available for transport to aquatic ecosystems (i.e., stream and lake) as dissolved organic matter (DOM) and fine particulate organic matter (POM). These DOM and POM are not only important food sources for the aquatic food web, but also a significant feedback if remineralized during transport. In this work, we collected water samples along a stream from the headwater in the Permafrost region to the downstream in the Qinghai Lake. The concentration and composition of DOM were determined using high temperature combustion analysis, UV- Vis absorption spectroscopy and fluorescence spectroscopy. The concentration of dissolved organic carbon decreased sharply from 13.87 mg/L to 4.32 mg/L from collapsing permafrost area (3850 m a.s.l.) to the foot of the mountain (3200 m a.s.l.), and then fluctuated in a narrow range between 3.00 mg/L and 4.50 mg/L. The DOM with high humic-like fluorescence, specific UV absorbance (SUVA254), and low spectral slope ratio (S275-295) and fluorescence index (FI) was observed in the headwater, which was distinct difference from that at the middle and downstream area where the DOM are less aromatic and low molecular weight. Meanwhile, the freshness index (β/α) increased slightly in mid and down-stream. This increasing trend for FI and β/α indicated a contribution of recently in situ produced DOM by aquatic bacteria and algae in the stream. We speculate that the biological process is an important way to cause the chemical change of DOM composition and concentration, and therefore the thawing and transport of permafrost carbon may play a key role in sustaining the alpine stream ecosystem.

One century sedimentary record of lead and zinc pollution in Yangzong Lake, a highland lake in southwestern China.

PubMed

Zhang, Enlou; Liu, Enfeng; Shen, Ji; Cao, Yanmin; Li, Yanling

2012-01-01

Reconstruction of trace metal pollution histories and sources may help us to regulate current pollutant discharge. This is especially important for the highland lakes in southwestern China, which are facing trace metals pollution. We present sedimentary records of 11 metals accumulated in Yangzong Lake since the 1870's, a highland lake in southwestern China. Pollution of lead and zinc (Pb and Zn) was differentiated based on principal component analysis, geochemical normalization, and lead isotope ratios. Nearly all the metals as well as grain size composition show generally constant values before the mid-1980's, denoting stable detrital input in the catchment. Fluctuations in the concentrations of the metals as well as grain size composition since the mid-1980's indicate an increase in soil erosion with strengthened human disturbance in the catchment. After geochemical normalization, Pb and Zn showed constant values before 1990 AD and then a gradual increase in parallel with the variations in 208Pb/206Pb and 207Pb/206Pb ratios, indicating that Pb and Zn pollution occurred. Combining the data of 208pb/206Pb and 207Pb/6Pb ratios in the sediments of Yangzong Lake, leaded gasoline, Pb-Zn ore and coal, and consumption or production historical trends, we deduced that the enhanced Pb and Zn pollution in Yangzong Lake is caused primarily by ore mining and refining.

Methane distribution and transportation in Lake Chaohu: a shallow eutrophic lake in Eastern China

NASA Astrophysics Data System (ADS)

Zhang, L.; Shen, Q.

2016-12-01

Global warming and eutrophication are two world widely concerned environmental problems. Methane is the second important greenhouse gas, and lake has been proven as a quite important natural source of methane emission. More methane may emit from eutrophic lake due to the higher organic matter deposition in the lake sediment. Lake Chaohu is a large and shallow eutrophic lake in eastern China (N31°25' 31°43', E117°16' 117°05'), with an area of 770 km2 and a mean depth of 2.7 m. To examine methane distribution and transportation in this eutrophic lake, field study across different seasons was carried out with 20 study sites in the lake. Samples from the different water and sediment depth was collected using headspace bottle, and methane content was measured by gas chromatography using a flame ionization detector. The potential methane production in the sediment was examined by an indoor incubation experiment. Methane flux from sediment to the overlying water was calculated by Fick's law, and methane emission from surface to the air was calculated at the same time. The results indicates that more methane accumulated in the water of northwestern bay in this lake, and higher methane release rates was also found at this area. Methane increases gradually with depth in the top 10 cm in sediment cores, then it almost keeps at constant state in the deeper sediment. In the sediment from northwestern bay, more methane content and the higher potential methane production was found compared to the sediment from the east area of this lake.

Holocene Asian monsoon evolution revealed by a pollen record from an alpine lake on the southeastern margin of the Qinghai-Tibetan Plateau, China

NASA Astrophysics Data System (ADS)

Zhang, Enlou; Wang, Yongbo; Sun, Weiwei; Shen, Ji

2016-02-01

We present the results of pollen analyses from a 1105 cm long sediment core from Wuxu Lake in southwestern China, which depict the variations of the East Asian winter monsoon (EAWM) and the Indian summer monsoon (ISM) during the last 12.3 ka. During the period of 12.3 to 11.3 cal ka BP, the dominance of Betula forest and open alpine shrub and meadow around Wuxu Lake indicates a climate with relatively cold winters and dry summers, corresponding to the Younger Dryas event. Between 11.3 and 10.4 cal ka BP, further expansion of Betula forest and the retreat of alpine shrubs and meadows reflect a greater seasonality with cold winters and gradually increasing summer precipitation. From 10.4 to 4.9 cal ka BP, the dense forest understory, together with the gradual decrease in Betula forest and increase in Tsuga forest, suggest that the winters became warmer and summer precipitation was at a maximum, corresponding to the Holocene climatic optimum. Between 4.9 and 2.6 cal ka BP, Tsuga forest and alpine shrubs and meadows expanded significantly, reflecting relatively warm winters and decreased summer precipitation. Since 2.6 cal ka BP, reforestation around Wuxu Lake indicates a renewed humid period in the late Holocene; however, the vegetation in the catchment may also have been affected by grazing activity during this period. The results of our study are generally consistent with previous findings; however, the timing and duration of the Holocene climatic optimum from different records are inconsistent, reflecting real contrast in local rainfall response to the ISM. Overall, the EAWM is broadly in-phase with the ISM on the orbital timescale, and both monsoons exhibit a trend of decreasing strength from the early to late Holocene, reflecting the interplay of solar insolation receipt between the winter and summer seasons and El Niño-Southern Oscillation strength in the tropical Pacific.

Holocene Asian monsoon evolution revealed by a pollen record from an alpine lake on the southeastern margin of the Qinghai-Tibetan Plateau, China

NASA Astrophysics Data System (ADS)

Zhang, E.; Wang, Y.; Sun, W.; Shen, J.

2015-10-01

We present the results of pollen analyses from a 1105-cm-long sediment core from Wuxu Lake in southwestern China, which depict the variations of the East Asian winter monsoon (EAWM) and the Indian summer monsoon (ISM) during the last 12.3 ka. During the period of 12.3 to 11.3 cal ka BP, the dominance of Betula forest and open alpine shrub and meadow around Wuxu Lake indicates a climate with relatively cold winters and dry summers, corresponding to the Younger Dryas event. Between 11.3 and 10.4 cal ka BP, further expansion of Betula forest and the retreat of alpine shrubs and meadows reflect a greater seasonality with cold winters and gradually increasing summer precipitation. From 10.4 to 4.9 cal ka BP, the dense forest understory, together with the gradual decrease in Betula forest and increase in Tsuga forest, suggest that the winters became warmer and summer precipitation was at a maximum, corresponding to the Holocene climatic optimum. Between 4.9 and 2.6 cal ka BP, Tsuga forest and alpine shrubs and meadows expanded significantly, reflecting relatively warm winters and decreased summer precipitation. Since 2.6 cal ka BP, reforestation around Wuxu Lake indicates a renewed strengthening of the ISM in the late Holocene; however, the vegetation in the catchment may also have been affected by grazing activity during this period. The results of our study are generally consistent with previous findings; however, the timing and duration of the Holocene climatic optimum from different records are inconsistent, reflecting real contrast in local rainfall response to the ISM. Overall, the EAWM is broadly in-phase with the ISM on the orbital timescale, and both monsoons exhibit a trend of decreasing strength from the early to late Holocene, reflecting the interplay of solar insolation receipt between the winter and summer seasons and El Niño Southern Oscillation strength in the tropical Pacific.

Antibiotics and Antibiotic Resistance Genes in Sediment of Honghu Lake and East Dongting Lake, China.

PubMed

Yang, Yuyi; Cao, Xinhua; Lin, Hui; Wang, Jun

2016-11-01

Sediment is an ideal medium for the aggregation and dissemination of antibiotics and antibiotic resistance genes (ARGs). The levels of antibiotics and ARGs in Honghu Lake and East Dongting Lake of central China were investigated in this study. The concentrations of eight antibiotics (four sulfonamides and four tetracyclines) in Honghu Lake were in the range 90.00-437.43 μg kg -1 (dry weight (dw)) with mean value of 278.21 μg kg -1 dw, which was significantly higher than those in East Dongting Lake (60.02-321.04 μg kg -1 dw, mean value of 195.70 μg kg -1 dw). Among the tested three sulfonamide resistance genes (sul) and eight tetracycline resistance genes (tet), sul1, sul2, tetA, tetC, and tetM had 100 % detection frequency in sediment samples of East Dongting Lake, while only sul1, sul2, and tetC were observed in all samples of Honghu Lake. The relative abundance of sul2 was higher than that of sul1 at p < 0.05 level in both lakes. The relative abundance of tet genes in East Dongting Lake was in the following order: tetM > tetB > tetC > tetA. The relative abundance of sul1, sul2, and tetC in East Dongting Lake was significantly higher than those in Honghu Lake. The abundance of background bacteria may play an important role in the horizontal spread of sul2 and tetC genes in Honghu Lake and sul1 in East Dongting Lake, respectively. Redundancy analysis indicated that tetracyclines may play a more important role than sulfonamides in the abundance of sul1, sul2, and tetC gens in Honghu Lake and East Dongting Lake.

Impacts of Land-Use Changes on the Lakes across the Yangtze Floodplain in China.

PubMed

Xie, Cong; Huang, Xin; Mu, Hongqiang; Yin, Wei

2017-04-04

The middle and lower Yangtze (MLY) floodplain has one of the most densely distributed lake clusters in China but suffered from long-term lake reclamation and wetland degradation due to intensive cultivation, fish rearing, and urban expansion over the past several decades. As a land-use alternation to support human life, the conversion of lakes to cropland, aquaculture ponds, and human settlements provides essential ecosystem goods at the expense of the deterioration of wetland environment. To quantify the driving factors of lake changes, we investigated the land-use transitions from lakes (≥1 km 2 ) between 1975 and 2015 using Landsat remote sensing data. We found that the dramatic decline in lake area (a net decrease of 13.8 ± 1.4%) over the four decades was largely attributed to human-induced transformation from lakes to cropland, fish ponds, and built-up areas, accounting for 34.6%, 24.2%, and 2.5% of the total area reduction, respectively. The remaining loss, associated with vegetation (37.3%) and bare land (1.4%) and coming mainly from China's two largest freshwater lakes (Poyang and Dongting), can be explained by climate variation, sediment deposition, and hydrological regulation. These findings shed new light on the quantitative impacts of human activities and climate variation on lake changes and provide a scientific foundation for wetland management decision-making.

Free-electron laser power beaming to satellites at China Lake, California

NASA Astrophysics Data System (ADS)

Bennett, Harold E.; Rather, John D.; Montgomery, Edward E.

1994-05-01

Laser power beaming of energy through the atmosphere to a satellite can extend its lifetime by maintaining the satellite batteries in operating condition. An alternate propulsion system utilizing power beaming will also significantly reduce the initial insertion cost of these satellites, which now are as high as $72,000/lb for geosynchronous orbit. Elements of the power beaming system are a high-power laser, a large diameter telescope to reduce diffractive losses, an adaptive optic beam conditioning system and possibly a balloon or aerostat carrying a large mirror to redirect the laser beam to low earth orbit satellites after it has traversed most of the earth's atmosphere vertically. China Lake, California has excellent seeing, averages 260 cloud-free days/year, has the second largest geothermal plant in the United States nearby for power, groundwater from the lake for cooling water, and is at the center of one of the largest restricted airspaces in the United States. It is an ideal site for such a laser power beaming system. Technological challenges in building such a system and installing it at China Lake are discussed.

Diversity and community structure of fungi through a permafrost core profile from the Qinghai-Tibet Plateau of China.

PubMed

Hu, Weigang; Zhang, Qi; Li, Dingyao; Cheng, Gang; Mu, Jing; Wu, Qingbai; Niu, Fujun; An, Lizhe; Feng, Huyuan

2014-12-01

While a vast number of studies have addressed the prokaryotic diversity in permafrost, characterized by subzero temperatures, low water activity, and extremely low rates of nutrient and metabolite transfer, fungal patterns have received surprisingly limited attention. Here, the fungal diversity and community structure were investigated by culture-dependent technique combined with cloning-restriction fragment length polymorphism (RFLP) analysis of sediments in a 10-m-long permafrost core from the Qinghai-Tibet Plateau of China. A total of 62 fungal phylotypes related to 10 distinct classes representing three phyla were recovered from 5031 clones generated in 13 environmental gene libraries. A large proportion of the phylotypes (25/62) that were distantly related to described fungal species appeared to be novel diversity. Ascomycota was the predominant group of fungi, with respect to both clone and phylotype number. Our results suggested there was the existence of cosmopolitan psychrophilic or psychrotolerant fungi in permafrost sediments, the community composition of fungi varied with increasing depth, while these communities largely distributed according to core layers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Epidemiology of Echinococcosis Among Schoolchildren in Golog Tibetan Autonomous Prefecture, Qinghai, China.

PubMed

Cai, Huixia; Guan, Yayi; Ma, Xiao; Wang, Liying; Wang, Hu; Su, Guoming; Zhang, Xuefei; Han, Xiumin; Ma, Junying; Liu, Yu Fang; Li, Jun; Zhang, Jingxiao; Wang, Yongshun; Wang, Wei; Du, Rui; Lei, Wen; Wu, Weiping

2017-03-01

Echinococcosis is a serious zoonotic parasitic disease that is highly endemic in Qinghai Province. The present study aimed to investigate the prevalence of echinococcosis among schoolchildren in Golog Tibetan Autonomous Prefecture to improve early diagnosis and treatment of patients and to provide information for echinococcosis prevention and control. A total of 11,260 schoolchildren from five counties (Maqin, Gander, Dari, Jiuzhi, and Banma) in Golog Tibetan Autonomous Prefecture, Qinghai Province, were screened for echinococcosis. Screening involved ultrasound imaging combined with serologic examination as an auxiliary diagnostic test. The prevalence of echinococcosis in the schoolchildren was 2.1% (235/11,260), with a rate of 0.8% for cystic echinococcosis (CE; 89/11,260) and 1.3% for alveolar echinococcosis (AE; 146/11,260). Additionally, one child had a mixed infection. The prevalence ranged between 1.1% and 4.1% among the five investigated counties, and was highest in Dari County (4.1%). The prevalence of echinococcosis was higher in girls than in boys and gradually increased with age. In addition, children with CE mainly had type 1 (CE1) and type 3 (CE3) lesions, and children with AE mainly had small-diameter calcified lesions, suggesting that they were in the early asymptomatic stage of echinococcosis. In conclusion, children of Golog Tibetan Autonomous Prefecture appear to exhibit the highest recorded prevalence of CE and AE globally. Ultrasound is useful for screening populations in regions where both CE and AE are endemic.

Epidemiology of Echinococcosis among Schoolchildren in Golog Tibetan Autonomous Prefecture, Qinghai, China

PubMed Central

Cai, Huixia; Guan, Yayi; Ma, Xiao; Wang, Liying; Wang, Hu; Su, Guoming; Zhang, Xuefei; Han, Xiumin; Ma, Junying; Liu, Yu Fang; Li, Jun; Zhang, Jingxiao; Wang, Yongshun; Wang, Wei; Du, Rui; Lei, Wen; Wu, Weiping

2017-01-01

Echinococcosis is a serious zoonotic parasitic disease that is highly endemic in Qinghai Province. The present study aimed to investigate the prevalence of echinococcosis among schoolchildren in Golog Tibetan Autonomous Prefecture to improve early diagnosis and treatment of patients and to provide information for echinococcosis prevention and control. A total of 11,260 schoolchildren from five counties (Maqin, Gander, Dari, Jiuzhi, and Banma) in Golog Tibetan Autonomous Prefecture, Qinghai Province, were screened for echinococcosis. Screening involved ultrasound imaging combined with serologic examination as an auxiliary diagnostic test. The prevalence of echinococcosis in the schoolchildren was 2.1% (235/11,260), with a rate of 0.8% for cystic echinococcosis (CE; 89/11,260) and 1.3% for alveolar echinococcosis (AE; 146/11,260). Additionally, one child had a mixed infection. The prevalence ranged between 1.1% and 4.1% among the five investigated counties, and was highest in Dari County (4.1%). The prevalence of echinococcosis was higher in girls than in boys and gradually increased with age. In addition, children with CE mainly had type 1 (CE1) and type 3 (CE3) lesions, and children with AE mainly had small-diameter calcified lesions, suggesting that they were in the early asymptomatic stage of echinococcosis. In conclusion, children of Golog Tibetan Autonomous Prefecture appear to exhibit the highest recorded prevalence of CE and AE globally. Ultrasound is useful for screening populations in regions where both CE and AE are endemic. PMID:28070013

Continuous Change Detection of Urban Lakes in Wuhan, China Using Multi-Temporal Remote Sensing Images

NASA Astrophysics Data System (ADS)

Zhang, W.; Kong, X.; Tan, G.; Zheng, S.

2018-04-01

Urban lakes are important natural, scenic and pattern attractions of the city, and they are potential development resources as well. However, lots of urban lakes in China have been shrunk significantly or disappeared due to rapid urbanization. In this study, four Landsat images were used to perform a case study for lake change detection in downtown Wuhan, China, which were acquired on 1991, 2002, 2011 and 2017, respectively. Modified NDWI (MNDWI) was adopted to extract water bodies of urban areas from all these images, and OTSU was used to optimize the threshold selection. Furthermore, the variation of lake shrinkage was analysed in detail according to SVM classification and post-classification comparison, and the coverage of urban lakes in central area of Wuhan has decreased by 47.37 km2 between 1991 and 2017. The experimental results revealed that there were significant changes in the surface area of urban lakes over the 27 years, and it also indicated that rapid urbanization has a strong impact on the losses of urban water resources.

Mercury concentration in the muscle of seven fish species from Chagan Lake, Northeast China.

PubMed

Zhu, Lilu; Yan, Baixing; Wang, Lixia; Pan, Xiaofeng

2012-03-01

Chagan Lake is located downstream of the Second Songhua River basin in Northeast China. It is one of the top ten inland freshwater lakes, and an important aquatic farm in China. The lake has been receiving large amounts (currently at 1.5 × 10(8) m(3)/a) of water from the river since 1984. This would pose a threat to the aquatic system of the lake because the river was seriously polluted with mercury in 1970s-1980s. The current study is the first to report the total mercury concentrations in fish found in the lake. Mercury concentrations in seven fish species collected from the lake in January 2009 were determined. The related human health risk from fish consumption was also assessed. The average concentration of mercury in the fish was 18.8 μg/kg of wet weight, ranging from 4.5 to 37.6 μg/kg of wet weight. A large difference in the mercury concentrations among the fish species was found. The mercury concentration was found to be higher in carnivorous species and lower in omnivorous and herbivorous species. This demonstrates greater mercury bioaccumulation in fish species at higher trophic levels. Mercury concentrations in fish showed significant positive correlations with age, length, and weight. No significant relationship was found between mercury concentrations in fish and the habitat preferences. Mercury concentrations in fish from the lake were within the limits of the international and national standards of China established for mercury. According to the reference doses established by the United States Environmental Protection Agency, the maximum safe consuming quantity considering all the fish was 297.3 g/day/person, which was more than five times as much as the current quantity (50 g/day/person) consumed by the local residents. This investigation indicates that the historical pollution of the Second Songhua River has not caused mercury bioaccumulation in fish muscle tissue of Chagan Lake. The present consumption of fish from the lake in the local area

Comparison of methanogen diversity of yak (Bos grunniens) and cattle (Bos taurus) from the Qinghai-Tibetan plateau, China.

PubMed

Huang, Xiao Dan; Tan, Hui Yin; Long, Ruijun; Liang, Juan Boo; Wright, André-Denis G

2012-10-19

Methane emissions by methanogen from livestock ruminants have significantly contributed to the agricultural greenhouse gas effect. It is worthwhile to compare methanogen from "energy-saving" animal (yak) and normal animal (cattle) in order to investigate the link between methanogen structure and low methane production. Diversity of methanogens from the yak and cattle rumen was investigated by analysis of 16S rRNA gene sequences from rumen digesta samples from four yaks (209 clones) and four cattle (205 clones) from the Qinghai-Tibetan Plateau area (QTP). Overall, a total of 414 clones (i.e. sequences) were examined and assigned to 95 operational taxonomic units (OTUs) using MOTHUR, based upon a 98% species-level identity criterion. Forty-six OTUs were unique to the yak clone library and 34 OTUs were unique to the cattle clone library, while 15 OTUs were found in both libraries. Of the 95 OTUs, 93 putative new species were identified. Sequences belonging to the Thermoplasmatales-affiliated Linage C (TALC) were found to dominate in both libraries, accounting for 80.9% and 62.9% of the sequences from the yak and cattle clone libraries, respectively. Sequences belonging to the Methanobacteriales represented the second largest clade in both libraries. However, Methanobrevibacter wolinii (QTPC 110) was only found in the cattle library. The number of clones from the order Methanomicrobiales was greater in cattle than in the yak clone library. Although the Shannon index value indicated similar diversity between the two libraries, the Libshuff analysis indicated that the methanogen community structure of the yak was significantly different than those from cattle. This study revealed for the first time the molecular diversity of methanogen community in yaks and cattle in Qinghai-Tibetan Plateau area in China. From the analysis, we conclude that yaks have a unique rumen microbial ecosystem that is significantly different from that of cattle, this may also help to explain why

Comparison of methanogen diversity of yak (Bos grunniens) and cattle (Bos taurus) from the Qinghai-Tibetan plateau, China

PubMed Central

2012-01-01

Background Methane emissions by methanogen from livestock ruminants have significantly contributed to the agricultural greenhouse gas effect. It is worthwhile to compare methanogen from “energy-saving” animal (yak) and normal animal (cattle) in order to investigate the link between methanogen structure and low methane production. Results Diversity of methanogens from the yak and cattle rumen was investigated by analysis of 16S rRNA gene sequences from rumen digesta samples from four yaks (209 clones) and four cattle (205 clones) from the Qinghai-Tibetan Plateau area (QTP). Overall, a total of 414 clones (i.e. sequences) were examined and assigned to 95 operational taxonomic units (OTUs) using MOTHUR, based upon a 98% species-level identity criterion. Forty-six OTUs were unique to the yak clone library and 34 OTUs were unique to the cattle clone library, while 15 OTUs were found in both libraries. Of the 95 OTUs, 93 putative new species were identified. Sequences belonging to the Thermoplasmatales-affiliated Linage C (TALC) were found to dominate in both libraries, accounting for 80.9% and 62.9% of the sequences from the yak and cattle clone libraries, respectively. Sequences belonging to the Methanobacteriales represented the second largest clade in both libraries. However, Methanobrevibacter wolinii (QTPC 110) was only found in the cattle library. The number of clones from the order Methanomicrobiales was greater in cattle than in the yak clone library. Although the Shannon index value indicated similar diversity between the two libraries, the Libshuff analysis indicated that the methanogen community structure of the yak was significantly different than those from cattle. Conclusion This study revealed for the first time the molecular diversity of methanogen community in yaks and cattle in Qinghai-Tibetan Plateau area in China. From the analysis, we conclude that yaks have a unique rumen microbial ecosystem that is significantly different from that of cattle

Hydroclimatic changes of Lake Bosten in Northwest China during the last decades.

PubMed

Yao, Junqiang; Chen, Yaning; Zhao, Yong; Yu, Xiaojing

2018-06-14

Bosten Lake, the largest inland freshwater lake in China, has experienced drastic change over the past five decades. Based on the lake water balance model and climate elasticity method, we identify annual changes in the lake's water components during 1961-2016 and investigate its water balance. We find a complex pattern in the lake's water: a decrease (1961-1987), a rapid increase (1988-2002), a drastic decrease (2003-2012), and a recent drastic increase (2013-2016). We also estimated the lake's water balance, finding that the drastic changes are caused by a climate-driven regime shift coupled with human disturbance. The changes in the lake accelerated after 1987, which may have been driven by regional climate wetting. During 2003 to 2012, implementation of the ecological water conveyance project (EWCP) significantly increased the lake's outflow, while a decreased precipitation led to an increased drought frequency. The glacier retreating trend accelerated by warming, and caused large variations in the observed lake's changes in recent years. Furthermore, wastewater emissions may give rise to water degradation, human activity is completely changing the natural water cycle system in the Bosten Lake. Indeed, the future of Bosten Lake is largely dependent on mankind.

Free-electron laser power beaming to satellites at China Lake, California

NASA Astrophysics Data System (ADS)

Bennett, Harold E.; Rather, John D.; Montgomery, Edward E.

1994-05-01

Laser power beaming of energy through the atmosphere to a satellite can extend its lifetime by maintaining the satellite batteries in operating condition. An alternate propulsion system utilizing power beaming will also significantly reduce the initial insertion cost of these satellites, which now are as high as $DLR72,000/lb for geosynchronous orbit. Elements of the power beaming system are a high-power laser, a large diameter telescope to reduce diffractive losses, an adaptive optic beam conditioning system and possibly a balloon or aerostat carrying a large mirror to redirect the laser beam to low earth orbit satellites after it has traversed most of the earth's atmosphere vertically. China Lake, California has excellent seeing, averages 260 cloud-free days/year, has the second largest geothermal plant in the United States nearby for power, groundwater from the lake for cooling water, and is at the center of one of the largest restricted airspaces in the United States. It is an ideal site for such a laser power beaming system. Technological challenges in building such a system and installing it at China Lake will be discussed.

A 16-ka oxygen-isotope record from Genggahai Lake on the northeastern Qinghai-Tibetan Plateau: Hydroclimatic evolution and changes in atmospheric circulation

NASA Astrophysics Data System (ADS)

Qiang, Mingrui; Song, Lei; Jin, Yanxiang; Li, Yuan; Liu, Li; Zhang, Jiawu; Zhao, Yan; Chen, Fahu

2017-04-01

Moisture source history and changes in atmospheric circulation are the most important attributes for portraying past climate changes and for estimating possible future trends. However, few climate records reflecting these attributes are available from the marginal zones of the Asian summer monsoon. Here, we present a record of the oxygen isotopic composition of authigenic carbonates (δ18Ocarb) of sequential sediments from Genggahai Lake in the northeastern Qinghai-Tibetan Plateau (QTP). Isotopic analyses were performed on the fine-grained carbonate fraction (<38 μm), mollusc shells, and stem encrustations from submerged plants. The stratigraphic variations of the δ18O record from the different carbonate components exhibit a remarkably similar pattern, probably reflecting the fact that δ18Ocarb variability was controlled primarily by changes in the oxygen isotopic composition of the lake water (δ18OLW). Disequilibrium effects and water temperature are precluded as major factors affecting the δ18Ocarb variations. Genggahai Lake is hydrologically open and characterized by a rapid discharge rate, as indicated by analysis of the hydrological setting of the lake system and by the observed significant positive correlation between δ18OLW and the oxygen isotopic composition of the inflowing water (δ18OI). Under such hydrological conditions, we argue that the isotopic signals of different moisture sources should be reflected in the carbonate isotopic composition. Furthermore, placing the δ18Ocarb record in the context of regional palaeoclimate archives, we found that the isotopic signals, particularly the negative shifts from the average values, cannot be interpreted consistently, despite a process of evaporative enrichment at the lake surface. During the early- to mid-Holocene, low δ18Ocarb values during 10.6-9.4 and 7.4-6.3 ka were associated with higher lake levels, and thus the record may have been significantly affected by a strengthened Asian summer monsoon

Inputting history of heavy metals into the inland lake recorded in sediment profiles: Poyang Lake in China.

PubMed

Yuan, Guo-Li; Liu, Chen; Chen, Long; Yang, Zhongfang

2011-01-15

The temporal and spatial distribution of heavy metals (Cd, Hg, Pb, As and Cr) in Poyang Lake, the largest freshwater lake (3050 km(2)) in China, were studied based on the sedimentary profiles. For this purpose, eight sedimentary cores were selected which located at lake area, outfall of lake and the main branch rivers, respectively. High-resolution profiles with interval 2 cm were used for analyzing the concentration of metals, and the ages of them were determined by (210)Pb and (137)Cs isotopic dating. While studying the change of metals concentration with the age in profile, it is found that the concentration of them in sediments was influenced not only by the sources in history but also by the sediment types. Based on this detailed work, the inventory and burden of heavy metals per decade were estimated in lake area during the past 50 years. Significantly, rivers-contribution ratio per decade was estimated to distinguish each river's contribution of heavy metals into lake while river-flux in history and metals concentration in profiles were considered as calculating factors. So, our research provides a proof to well understand the sedimentary history and the inputting history of heavy metals from main rivers into an inland lake. Copyright © 2010 Elsevier B.V. All rights reserved.

The Qinghai-Tibetan plateau: how high do Tibetans live?

PubMed

Wu, T

2001-01-01

A lower incidence of chronic mountain sickness (CMS) has apparently been observed in Tibetans in comparison to Andeans of South America. In the past, the hypothesis of "geographic differences" has been constructed to explain these population differences. In order to assess the importance of this hypothesis in the development of CMS, this article will first review the geographic factors of the Qinghai-Tibetan plateau where Tibetans live. The plateau is bounded by the Himalayas in the southwest and the Kunlun and Aljin mountains in the northeast. It towers over southwestern China at an average elevation of 4000 m above sea level and is known as "the roof of the world." Covering more than 2.5 million km(2), the Qinghai-Tibetan plateau is the highest and largest plateau in the world. The plateau has a highland continental climate and a very complex topography with great variations. Second, at what altitude do Tibetans live? In 1990 it was estimated that 4,594,188 Tibetans live on the plateau, with 53% living at an altitude over 3500 m. Fairly large numbers (about 600,000) live at an altitude exceeding 4500 m in the Chantong-Qingnan area. People of Tibetan ethnic descent are lifelong high-altitude residents and cannot easily move to higher or lower elevations. Over 90% of the population are engaged in farming and herding. The upper altitude limit of crops is around 4500 m, while the nomads reside above 4800 m and 5500 m. Recently, mining activities in the plateau have sustained a part of the population that lives permanently at altitudes between 3700 and 6000 m. Therefore, the Tibetans living in the Qinghai-Tibetan plateau live at an altitude as high as the Andeans in South America. Thus the apparently low incidence of CMS in Tibetans cannot be ascribed to "geographic differences." We propose that the genetic adaptation to hypoxia that has occurred in Tibetans is of importance in CMS.

Effects of Yak grazing on plant community characteristics of meadow grasslands in the Qinghai-Tibetan Plateau, China

NASA Astrophysics Data System (ADS)

Chai, Linrong; Hou, Fujiang; Bowatte, Saman; Cheng, Yunxiang

2017-04-01

The Qinghai-Tibetan Plateau (QTP) is an important part of the global terrestrial ecosystem that provides many ecological roles such as biodiversity protection, upper watersheds for large rivers, circulation of materials, energy balance and provision of forage and habitat for livestock and wildlife. Approximately 40% of the QTP is alpine meadow grasslands and yak farming is one of the dominant land use activities. In recent years, the rapid increase in the number of yaks grazing on meadow grasslands has raised concerns about grassland degradation. In this study we examined the effects of yak grazing on the grassland community characteristics to evaluate the degradation potential of alpine meadow in the QTP. The experiment was carried out on three farms, in close proximity to each other, that were operating at different grazing intensities in Maqu county (N35°58', E101°53', altitude 3650m) of the QTP in the Gansu province in China. We tested 4 levels of yak grazing intensities; control (no grazing), light (2.6yak/ha), moderate (3.5yak/ha) and high (6.5yak/ha ). We hypothesized that greater intensity of grazing would significantly impact the plant community characteristics through trampling effects above and below ground. We found grazing significantly (P<0.05) impacted the above and below ground biomass. Above ground biomass was highest in the non grazed area and lowest in the high grazing farm. In contrast, below ground biomass was significantly greater (p<0.05) in the moderate grazing farm compared to the non grazed area. The plant community density and the proportion of edible grass biomass were not significantly affected by the grazing treatments. The species richness was significantly reduced (p<0.05) in the moderate and high intensity grazing farms compared to the non grazed area. The soil moisture at 0-10 cm depth was significantly lower at the high grazing intensity farm compared to the non grazed area and in contrast soil temperature was significantly

Drastic change in China's lakes and reservoirs over the past decades.

PubMed

Yang, Xiankun; Lu, Xixi

2014-08-13

Using remote sensing images, we provided the first complete picture of freshwater bodies in mainland China. We mapped 89,700 reservoirs, covering about 26,870 km(2) and approximately 185,000 lakes with a surface area of about 82,232 km(2). Despite relatively small surface area, the total estimated storage capacity of reservoirs (794 km(3)) is triple that of lakes (268 km(3)). Further analysis indicates that reservoir construction has made the river systems strongly regulated: only 6% of the assessed river basins are free-flowing; 20% of assessed river basins have enough cumulative reservoir capacity to store more than the entire annual river flow. Despite the existence of 2,721 lakes greater than 1 km(2), we found that about 50 lakes greater than km(2) have formed on the Tibetan Plateau resulting from climate change. More than 350 lakes of ≥1 km(2) vanished in four other major lake regions. Although the disappearance of lakes happened in the context of global climate change, it principally reflects the severe anthropogenic impacts on natural lakes, such as, the excessive plundering of water resources on the Inner Mongolia-Xinjiang Plateau and serious destruction (land reclamation and urbanization) on the eastern plains.

Occurrence and Distribution of Microcystins in Lake Taihu, China

PubMed Central

Sakai, Hiroshi; Hao, Aimin; Iseri, Yasushi; Wang, Song; Kuba, Takahiro; Zhang, Zhenjia; Katayama, Hiroyuki

2013-01-01

The occurrence and distribution of microcystins were investigated in Lake Taihu, the third largest lake in China. An extensive survey, larger and broader in scale than previous studies, was conducted in summer 2010. The highest microcystin concentration was found at southern part of Taihu, which was newly included in this survey. In northern coastal areas, total cellular concentrations of 20 to 44 μg/L were observed. In northern offshore waters, levels were up to 4.8 μg/L. Microcystin occurrence was highly correlated with chemical oxygen demand, turbidity, and chlorophyll-a. Extracellular/total cellular microcystin (E/T) ratios were calculated and compared to other water quality parameters. A higher correlation was found using E/T ratios than original microcystin values. These results show that algal blooms are having a severe impact on Lake Taihu, and further and extensive monitoring and research are required to suppress blooms effectively. PMID:23853542

Creep characteristics and process analyses of a thaw slump in the permafrost region of the Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Sun, Zhe; Wang, Yibo; Sun, Yan; Niu, Fujun; Li, Guoyu; Gao, Zeyong

2017-09-01

A thaw slump in the permafrost region of the Qinghai-Tibet Plateau was monitored to investigate typical characteristics of creep positions and processes in combination with soil property analyses. The results show that the thaw settlement exhibits a contraction effect in the horizontal direction because of uneven thaw settlement. Slope displacement of creep occurs only in the top 50 cm of the soil. The gravimetric water content, soil porosity, and soil temperature are higher near the thaw slump in thaw seasons compared with the undisturbed soil; however, the shear strength is lower. Melting ground ice releases thaw water that converges along the slope and forms an overland flow at the front part of the gentle slope area and a ponding depression at the slope bottom. The analyses of slope stability using the infinite slope model shows that the headwall of the slope is inevitably unstable and slides under saturated conditions, whereas the gentle slope area and slope bottom with slight creep displacement are relatively stable. The small retrogressive thaw slump is in an early development stage. With increasing degree of thaw settlement and rate of erosion, the headwall will become steeper and a thermokarst lake will form at the slope bottom.

Seperating Long-term Hydrological Loading and Tectonic Deformation Observed with Multi-temporal SAR Interferometry and GPS in Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

LI, G.; Lin, H.

2014-12-01

From 2000 till present, most endorheic lakes in Tibetan plateau experienced quick increasing. Several largest lakes, gathered several meters depth water during one decade. Such massive mass increasing will lead to elastic and visco-elastic deformation of the ground. Qinghai-Tibetan Plateau is one the most active tectonic places in the world; monitoring its ground deformation is essential, when loading effect is a nuisance item. Due to the sparse distribution of GPS sites and most are roving sites, it is hard to distinguish tectonic component from mass loading effect. In this research we took Selin Co Lake located at Nujiang-Bangoin suture zone and evaluated long time ground deformation at hundred kilometers scale by multi-temporal SAR interferometry and simulate the ground deformation by loading history evaluated by multi mission satellite altimetry and optical images observation. At Nujiang-Bangoin suture zone, where GPS presented the maximum ground subsidence in Qinghai-Tibetan Plateau of 3.6mm/a which was found at the shore of Selin Co Lake from 1999 to 2011, when it experienced water level increasing of 0.7m/a. A model of elastic plate lying over Newtonian viscous half-space matches well with the results of multi-temporal SAR interferometry and GPS observations. We concluded that near Selin Co Lake area, ground deformation is composed by both tectonic and hydrological loading part. As SAR image coverage is much smaller than tectonic scale, we contribute the deformation detected by InSAR to loading effect. After evaluating and removing the hydrological loading effect, we founds that Nujiang-Bangoin suture zone did not experience quick subsidence, but only limited to 0.5mm/a. Selin Co Lake's quick volume increasing caused 3mm/a subsidence rate to the nearest GPS site. The Second nearest site showed the 1.4mm/a subsidence totally, which were composed by 1.05mm/a hydrological loading effect and the rest was tectonic. We also found that Young's Modulus is the most

How Universities Work: Understanding Higher Education Organization in Northwest China

ERIC Educational Resources Information Center

Berger, Joseph B.; Hudson, Katherine E.; Ramirez, Gerardo Blanco

2013-01-01

This study explores models of educational management used in postsecondary institutions in the five northwestern provinces of the People's Republic of China (Gansu, Ningxia, Qinghai, Shaanxi, and Xinjiang). As higher education in the People's Republic of China expands and undergoes significant changes, a nuanced understanding of the organizational…

[Geographic patterns and ecological factors correlates of snake species richness in China].

PubMed

Cai, Bo; Huang, Yong; Chen, Yue-Ying; Hu, Jun-Hua; Guo, Xian-Guang; Wang, Yue-Zhao

2012-08-01

Understanding large-scale geographic patterns of species richness as well its underlying mechanisms are among the most significant objectives of macroecology and biogeography. The ecological hypothesis is one of the most accepted explanations of this mechanism. Here, we studied the geographic patterns of snakes and investigated the relationships between species richness and ecological factors in China at a spatial resolution of 100 km×100 km. We obtained the eigenvector-based spatial filters by Principal Coordinates Neighbor Matrices, and then analyzed ecological factors by multiple regression analysis. The results indicated several things: (1) species richness of snakes showed multi-peak patterns along both the latitudinal and longitudinal gradient. The areas of highest richness of snake are tropics and subtropical areas of Oriental realm in China while the areas of lowest richness are Qinghai-Tibet Plateau, the grasslands and deserts in northern China, Yangtze-Huai Plain, Two-lake Plain, and the Poyang-lake Plain; (2) results of multiple regression analysis explained a total of 56.5% variance in snake richness. Among ecological factors used to explore the species richness patterns, we found the best factors were the normalized difference vegetation index, precipitation in the coldest quarter and temperature annual range ; (3) our results indicated that the model based on the significant variables that (P<0.05) uses a combination of precipitation of coldest quarter, normalized difference vegetation index and temperature annual range is the most parsimonious model for explaining the mechanism of snake richness in China. This finding demonstrates that different ecological factors work together to affect the geographic distribution of snakes in China. Studying the mechanisms that underlie these geographic patterns are complex, so we must carefully consider the choice of impact-factors and the influence of human activities.

Structure and spatial patterns of macrobenthic community in Tai Lake, a large shallow lake, China

USGS Publications Warehouse

Di Li,; Erickson, Richard A.; Song Tang,; Xuwen Li,; Niu, Zhichun; Xia Wang,; Hongling Liu,; Hongxia Yu,

2016-01-01

Tai Lake (Chinese: Taihu), the third-largest freshwater lake in China, suffers from harmful cyanobacteria blooms that are caused by economic development and population growth near the lake. Several studies have focused on phytoplankton in Tai Lake after a drinking water crisis in 2007; however, these studies primarily focused on microcystin bioaccumulation and toxicity to individual species without examining the effects of microcystin on macrobenthic community diversity. In this study, we conducted a survey of the lake to examine the effects of microcystine and other pollutants on marcobenthic community diversity. A totally of forty-nine species of macroinvertebrates were found in Tai Lake. Limnodrilus hoffmeisteri and Corbicula fluminea were the most abundant species. Cluster-analysis and one-way analysis of similarity (ANOSIM) identified three significantly different macrobenthic communities among the sample sites. More specifically, sites in the eastern bays, where aquatic macrophytes were abundant, had the highest diversity of macrobenthic communities, which were dominated by Bellamya aeruginosa, Bellamya purificata, L. hoffmeisteri, and Alocinma longicornis. Sites in Zhushan Bay contained relatively diverse communities, mainly composed of L. hoffmeisteri, C. fluminea, L. claparederanus, R. sinicus, and Cythura sp. Sites in the western region, Meiliang Bay and Wuli Bay had the lowest diversity, mainly composed ofL. hoffmeisteri, C. fluminea, Branchiura sowerbyi, and Rhyacodrilus sinicus. In addition, the relationships between macrobenthic metrics (Shannon–Wiener, Margalef, and Pielou) and environmental variables showed that community structure and spatial patterns of macrobenthos in Tai Lake were significantly influenced by chemical oxygen demand (CODCr), biochemical oxygen demand (BOD5), lead (Pb), and microcystin-LR (L for leucine and R for arginine). Our findings provide critical information that could help managers and policymakers

Landscape ecological assessment and eco-tourism development in the South Dongting Lake Wetland, China.

PubMed

He, Ping; Wang, Bao-zhong

2003-03-01

As an important resource and the living environment of mankind, wetland has become gradually a highlight, strongly concerned and intensively studied by scientists and sociologists. The governments in the world and the whole society have been paying more and more attention on it. The Dongting Lake of China is regarded as an internationally important wetland. For a rational development and protection of the wetland, an investigation and studied on its resources and its value to tourism in the South Dongting Lake was conducted, to create an assessment system of the ecological landscapes, and to evaluate qualitatively and quantitatively the value of wetland landscape to the ecotourism. The results showed that the scenic value of the South Dongting Lake Wetland satisfied the criterion of AAAA grade of China national scenic attraction. The eco-tourism value of the landscape cultures in the South Dongting Lake Wetland was discussed with emphasis. It were formulated that a principle and frame of sustainable exploitation of the wetland landscapes and it was proposed as well that establishing a Wetland Park and developing eco-tourism in the South Dongting Lake Wetland is a fragile ecosystem with low resistance to the impact of the exploitation. Thus, we must pay intensively attention to the influence of exploitation on the landscape, take the ecological risk in account to employ a right countermeasure and avoid the negative affection.

Paleohydrology of China Lake basin and the context of early human occupation in the northwestern Mojave Desert, USA

NASA Astrophysics Data System (ADS)

Rosenthal, Jeffrey S.; Meyer, Jack; Palacios-Fest, Manuel R.; Young, D. Craig; Ugan, Andrew; Byrd, Brian F.; Gobalet, Ken; Giacomo, Jason

2017-07-01

Considerable prior research has focused on the interconnected pluvial basins of Owens Lake and Searles Lake, resulting in a long record of paleohydrological change in the lower Owens River system. However, the published record is poorly resolved or contradictory for the period encompassing the terminal Pleistocene (22,000 to 11,600 cal BP) and early Holocene (11,600-8200 cal BP). This has resulted in conflicting interpretations about the timing of lacustrine high stands within the intermediate basin of China Lake, which harbors one of the most extensive records of early human occupation in the western Great Basin and California. Here, we report a broad range of radiocarbon-dated paleoenvironmental evidence, including lacustrine deposits and shoreline features, tufa outcrops, and mollusk, ostracode, and fish bone assemblages, as well as spring and other groundwater-related deposits (a.k.a. "black mats") from throughout China Lake basin, its outlet, and inflow drainages. Based on 98 radiocarbon dates, we develop independent evidence for five significant lake-level oscillations between 18,000 and 13,000 cal BP, and document the persistence of groundwater-fed wetlands from the beginning of the Younger Dryas through the early Holocene (12,900-8200 cal BP); including the transition from ground-water fed lake to freshwater marsh between about 13,000 and 12,600 cal BP. Results of this study support and refine existing evidence that shows rapid, high-amplitude oscillations in the water balance of the Owens River system during the terminal Pleistocene, and suggest widespread human use of China Lake basin began during the Younger Dryas.

Ecological shift and resilience in China's lake systems during the last two centuries

NASA Astrophysics Data System (ADS)

Zhang, Ke; Dong, Xuhui; Yang, Xiangdong; Kattel, Giri; Zhao, Yanjie; Wang, Rong

2018-06-01

The worldwide decline of wetland ecosystems calls for an urgent reassessment of their current status from a resilience perspective. Understanding the trajectories of changes that have produced the current situation is fundamental for assessing system resilience. Here, we examine long-term dynamics of wetland ecosystem change by reviewing paleoecological records from 11 representative lakes in China. We identify unprecedented change in alga communities in the context of last two centuries. Striking ecological shifts have occurred in all lakes, yet with spatial and temporal differences. The long-term trajectories of change in diatom species composition and structure indicate gradually eroded system resilience. These ecological shifts were shaped by socio-economic activities as China transformed from a rural agricultural to an industrialized society within the last several decades, during which multiple drivers have accumulated and acted synergistically. The balance between ecosystem and society, which appeared to exist for thousands of years, was broken by increasing population, new technology, and urbanization since the 1980s. The consequences are the emergence of new positive feedbacks with the potential to drive the coupled systems into undesirable states. By linking long-term social and ecological change at a regional scale, our study provides a novel contribution to the understanding of lake ecosystems resilience in present-day China. We argue that sustaining wetland ecosystems requires integrated approaches that incorporate a deeper understanding of social-ecological dynamics over decadal-centennial timescales to address the complex underlying mechanisms leading to the current degradation.

Intentional introduction of Artemia sinica (Anostraca) in the high-altitude Tibetan lake Dangxiong Co: the new population and consequences for the environment and for humans

NASA Astrophysics Data System (ADS)

Jia, Qinxian; Anufriieva, Elena; Liu, Xifang; Kong, Fanjing; Shadrin, Nickolai

2015-11-01

The imbalance between supply and demand of Artemia cysts in China and around the world is increasing now. Salt lakes in Tibet may contribute to the solution of the problem. In Northern Tibet there are 26 saline lakes whose salinity and temperature may support Artemia survival at an altitude of 4 000-5 100 m. We found Artemia in 15 of these lakes. The saline lakes with Artemia populations mainly belong to the shallow basin lakes, and the majority of these lakes are small in area. The total area of lakes without Artemia is more than 1 000 km2. Lake Dangxiong Co (Co means lake in Tibet) was chosen for the intentional introduction of Artemia sinica. In 2004, 850 g of A. sinica cysts, originating from Qinghai, were introduced in the lake. Surveys in 2006-2014 showed that the average abundance of Artemia adults in the lake gradually increased from 20 ind./m3 in 2006 to 1950 ind./m3 in 2013. We assume that two subpopulations of A. sinica, separated by depth, may exist in the lake. The new Artemia population caused an increase in the number of species of phytoplankton and heterotrophic protozoa with a decrease of their total abundance. Water transparency also increased. Dominance in phytoplankton passed from cyanobacteria to diatoms. Changes occurred not only in the lake ecosystem; the number of water birds using the lakes also dramatically increased. Preliminary calculations showed that is it possible to harvest at least about 150 t cysts per year from the lake as well as 3.2 thousand tons of frozen or 350 t of dried biomass of adult Artemia.

Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication--A Case Study in the Taihu Lake Basin (China).

PubMed

Lin, Chen; Ma, Ronghua; He, Bin

2015-12-24

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r² was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality.

Identifying Watershed Regions Sensitive to Soil Erosion and Contributing to Lake Eutrophication—A Case Study in the Taihu Lake Basin (China)

PubMed Central

Lin, Chen; Ma, Ronghua; He, Bin

2015-01-01

Taihu Lake in China is suffering from severe eutrophication partly due to non-point pollution from the watershed. There is an increasing need to identify the regions within the watershed that most contribute to lake water degradation. The selection of appropriate temporal scales and lake indicators is important to identify sensitive watershed regions. This study selected three eutrophic lake areas, including Meiliang Bay (ML), Zhushan Bay (ZS), and the Western Coastal region (WC), as well as multiple buffer zones next to the lake boundary as the study sites. Soil erosion intensity was designated as a watershed indicator, and the lake algae area was designated as a lake quality indicator. The sensitive watershed region was identified based on the relationship between these two indicators among different lake divisions for a temporal sequence from 2000 to 2012. The results show that the relationship between soil erosion modulus and lake quality varied among different lake areas. Soil erosion from the two bay areas was more closely correlated with water quality than soil erosion from the WC region. This was most apparent at distances of 5 km to 10 km from the lake, where the r2 was as high as 0.764. Results indicate that soil erosion could be used as an indicator for identifying key watershed protection areas. Different lake areas need to be considered separately due to differences in geographical features, land use, and the corresponding effects on lake water quality. PMID:26712772

Economic development influences on sediment-bound nitrogen and phosphorus accumulation of lakes in China.

PubMed

Ni, Zhaokui; Wang, Shengrui

2015-12-01

China has been confronted with serious water quality deterioration concurrent with rapid socioeconomic progress during the past 40 years. Consequently, knowledge about economic growth and lake water quality dynamics is important to understand eutrophication processes. Objectives were to (i) reconstruct historical nutrient accumulation and the basin economic progress on burial flux (BF); (ii) determine forms and structures of nitrogen (N) and phosphorus (P) in sediment and water using six cores in three of the most severely eutrophic lake areas in China (i.e., Eastern Plain, Yunnan-Guizhou Plain, and Inner Mongolia-Xinjiang regions). Results suggest that BFs of total nitrogen (TN) continued to increase in sediment, whereas total phosphorus (TP) levels were consistent or only slightly increased, except in highly polluted lakes during the past decades. Similar results were observed for concentrations of nutrients in water (i.e., increased N/P). This historical distribution pattern was correlated to long-term fertilization practices of farmers in the watershed (N fertilization exceeds that of P) and was contingent upon pollution control policies (e.g., emphasized P whereas N was ignored). Vertical profiles of BFs indicated that lake nutrient accumulation included three stages in China. Nutrient accumulation started in the 1980s, accelerated from the 1990s, and then declined after 2000. Before the 1980s, nutrients were relatively low and stable, with nutrient inputs being controlled by natural processes. Thereafter, N- and P-bound sediments dramatically increased due to the increasing influence of anthropogenic processes. Nutrients were primarily derived from industries and domestic sewage. After 2000, BFs of nutrients were steady and even decreased, owing to implementation of watershed load reduction policies. The decreasing NaOH-extracted P (Fe/Al-P) and increasing organic phosphorus (OP) indicated that the source of exogenous pollution underwent a shift. Inputs of

Assessment of Climate Driven Dynamics of Active Layer, Hydrological and Vegetation Status at the Qinghai-Tibet Plateau Using Dynamic Global Vegetation Model

NASA Astrophysics Data System (ADS)

Yang, Y.

2014-12-01

Extensive permafrost degradation starting from 1970s is observed at the Qinghai-Tibet Plateau , China. Degradation is attributed to an increase in mean annual ground temperature 0.1◦-0.5◦ C with mainly winter warming. The construction of Qinghai-Tibet Railway also influenced a state of permafrost in the area Permafrost degradation caused negative environmental consequences in the area. The areas covered by sand are expanding steadily making large concern of accelerating desertification. The general pathway of future joint dynamics of permafrost, vegetation and hydrological status at the Qinghai-Tibet Plateau is still poorly understood and foreseeable. Hydrology in the area is determined by heat-moisture dynamics of active layer. This dynamics is highly non-linear and depends as on external climatic variables temperature and precipitation, so on soil and rock properties (amount of sand against aeolian deposits in the Plateau) as well as vegetation cover, which determine thaw and freeze processes in the active layer and evaporation and run-off. SEVER DGVM was modified to include heat-moisture dynamics of active layer in the Qinghai-Tibet Plateau. SEVER DGVM imitates processes in 10 plant functional types at coarse resolution of 0.5 degrees. This model imitates behavior of average individual of each plant type in each grid cell through simulation years. Each of those grid cells processed independently. First, this model starts from "bare soil", placing a bit of each plant type and giving them some time to grow and achieve equilibrium. Then, including active layer thickness and soil moisture dynamics into this layer, it allows assessment of potential environmental dynamics in this area. Simulations demonstrate further degradation of pastureland and accelerating desertification processes in this vitally important water feed area for many Asian rivers. Negative environmental problems related to operation of Qinghai-Tibet are also assessed.

Interaction of hydrological regime and vegetation in a seasonally flooded lake wetland (Poyang Lake) in China

NASA Astrophysics Data System (ADS)

Zhang, Qi

2017-04-01

Hydrological regime has been widely recognized as one of the major forces determining vegetation distribution in seasonally flooded wetlands. To explore the influences of hydrological conditions on the spatial distribution of wetland vegetation, an experimental transect in Poyang Lake wetland, the largest freshwater lake in China, was selected as a study area. In-situ high time frequency observations of climate, soil moisture, groundwater level and surface water level were simultaneously conducted. Vegetation was sampled periodically to obtain species composition, diversity and biomass. Results show that significant hydrological gradient exists along the experimental transect. Both groundwater level and soil moisture demonstrate high correlation with the distribution of different communities of vegetation. Above- and belowground biomass present Gaussian models along the gradient of groundwater depth in growing seasons. It was found that the optimal average groundwater depths for above- and belowground biomass are 0.8 m and 0.5 m, respectively. Numerical simulations using HYDRUS-1D further indicated that the groundwater depths had significant influences on the water usage by vegetation, which suggested the high dependence of wetland vegetation on groundwater, even in a wet climate zone such as Poyang Lake. The study revealed new knowledge on the interaction of hydrological regime and wetland vegetation, and provided scientific support for an integrated management of balancing wetland ecology and water resources development in Poyang Lake, and other lake floodplain wetlands, with strong human interferences.

Lake sediment records on climate change and human activities in the Xingyun Lake catchment, SW China.

PubMed

Zhang, Wenxiang; Ming, Qingzhong; Shi, Zhengtao; Chen, Guangjie; Niu, Jie; Lei, Guoliang; Chang, Fengqin; Zhang, Hucai

2014-01-01

Sediments from Xinyun Lake in central Yunnan, southwest China, provide a record of environmental history since the Holocene. With the application of multi-proxy indicators (total organic carbon (TOC), total nitrogen (TN), δ13C and δ15N isotopes, C/N ratio, grain size, magnetic susceptibility (MS) and CaCO3 content), as well as accelerator mass spectrometry (AMS) 14C datings, four major climatic stages during the Holocene have been identified in Xingyun's catchment. A marked increase in lacustrine palaeoproductivity occurred from 11.06 to 9.98 cal. ka BP, which likely resulted from an enhanced Asian southwest monsoon and warm-humid climate. Between 9.98 and 5.93 cal. ka BP, a gradually increased lake level might have reached the optimum water depth, causing a marked decline in coverage by aquatic plants and lake productivity of the lake. This was caused by strong Asian southwest monsoon, and coincided with the global Holocene Optimum. During the period of 5.60-1.35 cal. ka BP, it resulted in a warm and dry climate at this stage, which is comparable to the aridification of India during the mid- and late Holocene. The intensifying human activity and land-use in the lake catchment since the early Tang Dynasty (∼1.35 cal. ka BP) were associated with the ancient Dian culture within Xingyun's catchment. The extensive deforestation and development of agriculture in the lake catchment caused heavy soil loss. Our study clearly shows that long-term human activities and land-use change have strongly impacted the evolution of the lake environment and therefore modulated the sediment records of the regional climate in central Yunnan for more than one thousand years.

[Evaluation of ecosystem resilience in the regions across Qinghai-Tibet railway based on GIS].

PubMed

Gao, Jiang-bo; Zhao, Zhi-qiang; Li, Shuang-cheng

2008-11-01

Based on GIS technique and the methods of mean-squared deviation weight decision and catastrophe progression, a more clear definition and associated evaluation for ecosystem resilience were given, with a case study in the regions across Qinghai-Tibet railway by using the indices of plant community coverage, species diversity, and biomass. It was shown that the areas with high ecosystem resilience were mainly located in the Qilian Mountain meadow grassland, Huangshui Valley needle-leaved and deciduous broad-leaved forest, and south Tanggula Mountain kobresia swamp meadow, while those with the lowest resilience were in the central part of Qaidam Basin, and the Kunlun Mountains. Most areas in the regions had higher or medium ecosystem resilience, with a trend of that in the south of Kunlun Mountains, the resilience in the north of the railway was lower, while in the east of Qaidam Basin (especially in the Qinghai Lake area), the resilience was lower in the south than in the north of the railway. Through the evaluation of ecosystem resilience, the key issues in the process of ecological resilience could be found, and corresponding effective measures would be pointed out to manage alpine ecosystems. Moreover, combining with the evaluation of vulnerability, scientific basis for regional development could be provided to avoid or mitigate the negative effects of human activities on eco-environment.

Two-decade reconstruction of algal blooms in China's Lake Taihu.

PubMed

Duan, Hongtao; Ma, Ronghua; Xu, Xiaofeng; Kong, Fanxiang; Zhang, Shouxuan; Kong, Weijuan; Hao, Jingyan; Shang, Linlin

2009-05-15

The algal blooming in the inland lakes has become a critically important issue for its impacts not only on local natural and social environments, but also on global human community. However, the occurrences of blooming on larger spatial scale and longer time scale have rarely been studied. As the third largest freshwater lake in China, Lake Taihu has drawn increasing attention from both public and scientific communities concerning its degradation. Using available satellite images, we reconstructed the spatial and temporal patterns of algal blooms in Lake Taihu through the pasttwo decades. The blooming characteristics over the past two decades were examined with the dynamic of initial blooming date being highlighted. The initial blooming dates were gradually becoming later and later from 1987 to 1997. Since 1998, however, the initial blooming date came earlier and earlier year by year, with approximately 11.42 days advancement per year. From 1987 to 2007, the annual duration of algal blooms lengthened year by year, in line with the substantial increases in the occurrences of algal blooms in spring and summer months. The algal blooms usually occur in northern bays and spread to center and south parts of Lake Taihu. The increases in previous winter's mean daily minimum temperature partially contributed to the earlier blooming onset. However, human activities, expressed as total gross domestic product (GDP) and population, outweighed the climatic contribution on the initial blooming date and blooming duration. This study may provide insights for the policy makers who try to curb the algal blooming and improve the water quality of inland freshwater lakes.

Water transparency distribution under varied currents in the largest river-connected lake of China.

PubMed

Wang, Hua; Zhao, Yijun; Zhang, Zhizhang; Pang, Yong; Liang, Dongfang

2017-01-01

Water transparency is an important ecological indicator for shallow lakes. The largest shallow lake, Poyang Lake, as well as the most typical river-connected lake in China was selected as the research area. In view of the complicated water-sediment conditions induced by its frequent water exchange with external rivers, the dominant factors driving water transparency were determined against the field investigated data from 2003 to 2013 and a specific driving function was established. A numerical model coupling suspended sediment, Chl-a and chemical oxygen demand was developed and validated, and the spatial water transparency distributions under three typical current structures in Poyang Lake, Gravity-style, Jacking-style and Backflow-style, were quantitatively estimated. The following results stood out: water transparency in the lake varied distinctly with the current status; Backflow-style current was basically characterized by the lowest water transparency, while that under Jacking-style was the highest due to the lower sediment carrying capacity. In some outlying regions in the lake, where the water current is hardly influenced by the mainstream, the water transparency was always kept at a stable level.

Biogeochemical zonation of sulfur during the discharge of groundwater to lake in desert plateau (Dakebo Lake, NW China).

PubMed

Su, Xiaosi; Cui, Geng; Wang, Huang; Dai, Zhenxue; Woo, Nam-Chil; Yuan, Wenzhen

2018-06-01

As one of the important elements of controlling the redox system within the hyporheic and hypolentic zone, sulfur is involved in a series of complex biogeochemical processes such as carbon cycle, water acidification, formation of iron and manganese minerals, redox processes of trace metal elements and a series of important ecological processes. Previous studies on biogeochemistry of the hyporheic and hypolentic zones mostly concentrated on nutrients of nitrogen and phosphorus, heavy metals and other pollutants. Systematic study of biogeochemical behavior of sulfur and its main controlling factors within the lake hypolentic zone is very urgent and important. In this paper, a typical desert plateau lake, Dakebo Lake in northwestern China, was taken for example within which redox zonation and biogeochemical characteristics of sulfur affected by hydrodynamic conditions were studied based on not only traditional hydrochemical analysis, but also environmental isotope evidence. In the lake hypolentic zone of the study area, due to the different hydrodynamic conditions, vertical profile of sulfur species and environmental parameters differ at the two sites of the lake (western side and center). Reduction of sulfate, deposition and oxidation of sulfide, dissolution and precipitation of sulfur-bearing minerals occurred are responded well to Eh, dissolved oxygen, pH, organic carbon and microorganism according to which the lake hypolentic zone can be divided into reduced zone containing H 2 S, reduced zone containing no H 2 S, transition zone and oxidized zone. The results of this study provide valuable insights for understanding sulfur conversion processes and sulfur biogeochemical zonation within a lake hypolentic zone in an extreme plateau arid environment and for protecting the lake-wetland ecosystem in arid and semiarid regions.

Metagenomics Reveals a Novel Virophage Population in a Tibetan Mountain Lake

PubMed Central

Oh, Seungdae; Yoo, Dongwan; Liu, Wen-Tso

2016-01-01

Virophages are parasites of giant viruses that infect eukaryotic organisms and may affect the ecology of inland water ecosystems. Despite the potential ecological impact, limited information is available on the distribution, diversity, and hosts of virophages in ecosystems. Metagenomics revealed that virophages were widely distributed in inland waters with various environmental characteristics including salinity and nutrient availability. A novel virophage population was overrepresented in a planktonic microbial community of the Tibetan mountain lake, Lake Qinghai. Our study identified coccolithophores and coccolithovirus-like phycodnaviruses in the same community, which may serve as eukaryotic and viral hosts of the virophage population, respectively. PMID:27151658

Spatial and temporal ecological risk assessment of unionized ammonia nitrogen in Tai Lake, China (2004-2015).

PubMed

Li, Yabing; Xu, Elvis Genbo; Liu, Wei; Chen, Yi; Liu, Hongling; Li, Di; Liu, Zhengtao; Giesy, John P; Yu, Hongxia

2017-06-01

Ammonia toxicity varies largely due to its pH- and temperature-dependent speciation (unionized ammonia nitrogen, NH 3 -N). The seasonal and long-term trend of ammonia risk in ecologically significant sections of Tai Lake, China was unknown. In this study, a two-level (deterministic and quantitative) method was developed to assess the special ecological risks posed by NH 3 -N at 37 sites during two seasons (February and September) of 2014 in Tai Lake. The long-term temporal (2004-2015) risk posed by NH 3 -N was also assessed by comparing annual quantitative risk values (probability of exceeding acute or chronic threshold values) in three key sections of Tai Lake. The results indicated the species living in the Tai Lake were at a 0.04% and 32.45% chance of risk due to acute exposure, and a 1.97% and 92.05% chance of risk due to chronic exposure in February and September of 2014, respectively. Alarmingly, the chronic ecological risks of NH 3 -N in the Lanshanzui section of the Tai Lake remained >30% from 2004 to 2011. The chronic risk of NH 3 -N in all three key sections of Tai Lake started to decrease in 2011. This was likely the consequence of the control practice of eutrophication implemented in the Tai Lake. A significant decline in diversity of the benthic invertebrate community of the Tai Lake could be associated with continuous exposure to ammonia over decades given different sensitivity of taxa to ammonia. The results laid a scientific foundation for risk assessment and management of ammonia in Tai Lake, China, and the developed two-level risk assessment approach can also be applied to other similar aquatic regions. Copyright © 2017 Elsevier Inc. All rights reserved.

Huguangyan Maar Lake (SE China): A solid record of atmospheric mercury pollution history in a non-remote region

NASA Astrophysics Data System (ADS)

Zeng, Yan; Chen, Jingan; Yang, Yongqiong; Wang, Jianxu; Zhu, Zhengjie; Li, Jian

2017-10-01

Mercury is a highly toxic metal that can cause harm to environment and human health. As atmospheric deposition is the main source of total Hg input to aquatic system in remote and pristine regions, almost all the studies on atmospheric Hg pollution history concentrated in these areas, while the studies in non-remote areas are much limited, especially for the long history records. In this study, Huguangyan Maar Lake, an undisturbed lake system at low altitude in China, was selected to reconstruct the atmospheric mercury pollution history. Variation patterns of TOC, Hg and non-residual Sr in the sediment core indicated that, compared to the direct atmospheric Hg deposition, the effect of either Hg scavenging from water column by algae or the catchment inputs of previously deposited Hg on the Hg accumulation in the lake sediment was limited. The sediment Hg content in Huguangyan Lake was mainly controlled by the atmospheric Hg deposition, and thus accurately reflected the atmospheric Hg pollution history. The Hga (Hg content from atmospheric deposition) in Huguangyan Lake presented a comparable variation pattern to that in remote sites. It had the same variation trend as the global atmospheric Hg before 1950 CE, which could be attributed to the Industrial Revolution. After that, it was mainly controlled by Hg emissions from Asian countries. The variation of Hga also indicated that atmospheric Hg deposition accelerated significantly since 2000 CE. This study, along with other investigations in remote sites in China, showed that the sediment Hg in Huguangyan Lake responded to the atmospheric Hg pollution more sensitively than in the alpine regions. It should be noted that, the more intensive acceleration of Hg deposition in Huguangyan Lake may imply that the South of China suffered from much more serious atmospheric Hg pollution than previous studies revealed.

Spatial Variability of Cyanobacteria and Heterotrophic Bacteria in Lake Taihu (China).

PubMed

Qian, Haifeng; Lu, Tao; Song, Hao; Lavoie, Michel; Xu, Jiahui; Fan, Xiaoji; Pan, Xiangliang

2017-09-01

Cyanobacterial blooms frequently occur in Lake Taihu (China), but the intertwined relationships between biotic and abiotic factors modulating the frequency and duration of the blooms remain enigmatic. To better understand the relationships between the key abiotic and biotic factors and cyanobacterial blooms, we measured the abundance and diversity of prokaryotic organisms by high-throughput sequencing, the abundance of key genes involved in microcystin production and nitrogen fixation or loss as well as several physicochemical parameters at several stations in Lake Taihu during a cyanobacterial bloom of Microcystis sp.. Measurements of the copy number of denitrification-related genes and 16S rRNA analyses show that denitrification potential and denitrifying bacteria abundance increased in concert with non-diazotrophic cyanobacteria (Microcystis sp.), suggesting limited competition between cyanobacteria and heterotrophic denitrifiers for nutrients, although potential bacteria-mediated N loss may hamper Microcystis growth. The present study provides insight into the importance of different abiotic and biotic factors in controlling cyanobacteria and heterotrophic bacteria spatial variability in Lake Taihu.

Thermal impacts of engineering activities and vegetation layer on permafrost in different alpine ecosystems of the Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Wu, Qingbai; Zhang, Zhongqiong; Gao, Siru; Ma, Wei

2016-08-01

Climate warming and engineering activities have various impacts on the thermal regime of permafrost in alpine ecosystems of the Qinghai-Tibet Plateau. Using recent observations of permafrost thermal regimes along the Qinghai-Tibet highway and railway, the changes of such regimes beneath embankments constructed in alpine meadows and steppes are studied. The results show that alpine meadows on the Qinghai-Tibet Plateau can have a controlling role among engineering construction effects on permafrost beneath embankments. As before railway construction, the artificial permafrost table (APT) beneath embankments is not only affected by climate change and engineering activities but is also controlled by alpine ecosystems. However, the change rate of APT is not dependent on ecosystem type, which is predominantly affected by climate change and engineering activities. Instead, the rate is mainly related to cooling effects of railway ballast and heat absorption effects of asphalt pavement. No large difference between alpine and steppe can be identified regarding the variation of soil temperature beneath embankments, but this difference is readily identified in the variation of mean annual soil temperature with depth. The vegetation layer in alpine meadows has an insulation role among engineering activity effects on permafrost beneath embankments, but this insulation gradually disappears because the layer decays and compresses over time. On the whole, this layer is advantageous for alleviating permafrost temperature rise in the short term, but its effect gradually weakens in the long term.

China Report, Economic Affairs

DTIC Science & Technology

1986-04-09

improve the quality of goods for export. Jinan Knitwear Mill imported advanced technology to replace obsolete equipment and raised product quality...concentrating their strength on improving technology and developing social productive forces, fully developing their own strong points and running...Discovered in Qinghai 44 INDUSTRY Fashion Design Booming Industry in China (XINHUA, 17 Mar 86) 45 b - Anhui Raw Materials Development

Temporal and spatial changes in nutrients and chlorophyll-a in a shallow lake, Lake Chaohu, China: an 11-year investigation.

PubMed

Yang, Libiao; Lei, Kun; Meng, Wei; Fu, Guo; Yan, Weijin

2013-06-01

Temporal and spatial changes of total nitrogen (TN), total phosphorus (TP) and chlorophyll-a (Chl-a) in a shallow lake, Lake Chaohu, China, were investigated using monthly monitoring data from 2001 through 2011. The results showed that the annual mean concentration ranges of TN, TP, and Chl-a were 0.08-14.60 mg/L, 0.02-1.08 mg/L, and 0.10-465.90 microg/L, respectively. Our data showed that Lake Chaohu was highly eutrophic and that water quality showed no substantial improvement during 2001 through 2011. The mean concentrations of TP, TN and Chl-a in the western lake were significantly higher than in the eastern lake, which indicates a spatial distribution of the three water parameters. The annual mean ratio of TN:TP by weight ranged from 10 to 20, indicating that phosphorus was the limiting nutrient in this lake. A similar seasonality variation for TP and Chl-a was observed. Riverine TP and NH4+ loading from eight major tributaries were in the range of 1.56 x 10(4)-5.47 x 10(4) and 0.19 x 10(4)-0.51 x 10(4) tons/yr over 2002-2011, respectively, and exceeded the water environmental capability of the two nutrients in the lake by a factor of 3-6. Thus reduction of nutrient loading in the sub-watershed and tributaries would be essential for the restoration of Lake Chaohu.

Integrated assessment on the vulnerability of animal husbandry to snow disasters under climate change in the Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wei, Yanqiang; Wang, Shijin; Fang, Yiping; Nawaz, Zain

2017-10-01

Animal husbandry is a dominant and traditional source of livelihood and income in the Qinghai-Tibetan Plateau. The Qinghai-Tibetan Plateau is the third largest snow covered area in China and is one of the main snow disaster regions in the world. It is thus imperative to urgently address the issue of vulnerability of the animal husbandry sector to snow disasters for disaster mitigation and adaptation under growing risk of these disasters as a result of future climate change. However, there is very few literature reported on the vulnerability of animal husbandry in the Qinghai-Tibetan Plateau. This assessment aims at identifying vulnerability of animal husbandry at spatial scale and to identify the reasons for vulnerability for adaptive planning and disaster mitigation. First, historical snow disaster characteristics have been analyzed and used for the spatial weight for vulnerability assessment. Second, indicator-based vulnerability assessment model and indicator system have been established. We combined risk of snow hazard, sensitivity of livestock to disaster, physical exposure to disaster, and community capacity to adapt to snow disaster in an integrated vulnerability index. Lastly, vulnerability of animal husbandry to snow disaster on the Qinghai-Tibetan Plateau has been evaluated. Results indicate that high vulnerabilities are mainly concentrated in the eastern and central plateau and that vulnerability decreases gradually from the east to the west. Due to global warming, the vulnerability trend has eased to some extent during the last few decades. High livestock density exposure to blizzard-prone regions and shortages of livestock barn and forage are the main reasons of high vulnerability. The conclusion emphasizes the important role of the local government and community to help local pastoralists for reducing vulnerability to snow disaster and frozen hazard. The approaches presented in this paper can be used for snow disaster mitigation, resilience

What caused the decline of China's largest freshwater lake? Attribution analysis on Poyang Lake water level variations in recent years

NASA Astrophysics Data System (ADS)

Ye, Xuchun; Xu, Chong-Yu; Zhang, Qi

2017-04-01

In recent years, dramatic decline of water level of the Poyang Lake, China's largest freshwater lake, has raised wide concerns about the water security and wetland ecosystem. This remarkable hydrological change coincided with several factors like the initial operation of the Three Gorges Dam (TGD) in 2003, the big change of lake bottom topography due to extensive sand mining in the lake since 2000, and also climate change and other human activities in the Yangtze River basin may add to this complexity. Questions raised to what extent that the lake hydrological changes is caused by climate change and/or human activities. In this study, quantitative assessment was conducted to clarify the magnitude and mechanism of specific influencing factors on recent lake decline (2003-2014), with reference to the period of 1980-1999. The attempts were achieved through the reconstruction of lake water level scenarios by the framework of neural network. Major result indicates that the effect of lake bottom topography change due to sand mining activities has became the dominant factor for the recent lake decline, especially in winter season with low water level. However, the effect of TGD regulation shows strong seasonal features, its effect can accounts for 33%-42% of the average water level decline across the lake during the impoundment period of September-October. In addition, the effect of climate change and other human activities over the Yangtze River basin needs to be highly addressed, which is particularly prominent on reducing lake water level during the summer flood season and autumn recession period. The result also revealed that due to different mechanism, the responses of the lake water level to the three influencing factors are not consistent and show great spatial and temporal differences.

Dongting Lake, China

NASA Technical Reports Server (NTRS)

2002-01-01

These images show dramatic change in the water at Dongting Lake in Hunan province, China. A flood crest surged down the Yangtze River in late August of this year, but the embankments made by residents there held. The left image was acquired on September 2, 2002 and shows the extent of the lake. The right image was obtained March 19, 2002 before the flooding began.

These images were acquired on September 2, 2002 and March 19,2002 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as

Evidence for the Importance of Atmospheric Nitrogen Deposition to Eutrophic Lake Dianchi, China

NASA Astrophysics Data System (ADS)

Zhan, X.; Bo, Y.; Zhou, F.; Liu, X.; Paerl, H. W.; Shen, J.; Wang, R.; Li, F. R.; Tao, S.; Yanjun, D.; Tang, X.

2017-12-01

Elevated atmospheric nitrogen (N) deposition has significantly influenced aquatic ecosystems, especially with regard to their N budgets and phytoplankton growth potentials. Compared to a considerable number of studies on oligotrophic lakes and oceanic waters, little evidence for the importance of N deposition has been generated for eutrophic lakes, even though emphasis has been placed on reducing external N inputs to control eutrophication in these lakes. Our high-resolution observations of atmospheric depositions and riverine inputs of biologically reactive N species into eutrophic Lake Dianchi (the sixth largest freshwater lake in China) shed new light onto the contribution of N deposition to total N loads. Annual N deposition accounted for 15.7% to 16.6% of total N loads under variable precipitation conditions, 2-fold higher than previous estimates (7.6%) for the Lake Dianchi. The proportion of N deposition to total N loads further increased to 27-48% in May and June when toxic blooms of the ubiquitous non-N2 fixing cyanobacteria Microcystis spp. are initiated and proliferate. Our observations reveal that reduced N (59%) contributes a greater amount than oxidized N to total N deposition, reaching 56-83% from late spring to summer. Progress toward mitigating eutrophication in Lake Dianchi and other bloom-impacted eutrophic lakes will be difficult without reductions in ammonia emissions and subsequent N deposition.

Changes in the radiocarbon reservoir age in Lake Xingyun, Southwestern China during the Holocene.

PubMed

Zhou, Aifeng; He, Yuxin; Wu, Duo; Zhang, Xiaonan; Zhang, Can; Liu, Zhonghui; Yu, Junqing

2015-01-01

Chronology is a necessary component of paleoclimatology. Radiocarbon dating plays a central role in determining the ages of geological samples younger than ca. 50 ka BP. However, there are many limitations for its application, including radiocarbon reservoir effects, which may cause incorrect chronology in many lakes. Here we demonstrate temporal changes in the radiocarbon reservoir age of Lake Xingyun, Southwestern China, where radiocarbon ages based on bulk organic matter have been reported in previous studies. Our new radiocarbon ages, determined from terrestrial plant macrofossils suggest that the radiocarbon reservoir age changed from 960 to 2200 years during the last 8500 cal a BP years. These changes to the reservoir effect were associated with inputs from either pre-aged organic carbon or 14C-depleted hard water in Lake Xingyun caused by hydrological change in the lake system. The radiocarbon reservoir age may in return be a good indicator for the carbon source in lake ecosystems and depositional environment.

[Diversity and faunal analysis of crustaceans in Potatso National Park, Shangri-La, China].

PubMed

Shu, Shu-Sen; Chen, Fei-Zhou; Yang, Jun-Xing; Yang, Xiao-Jun; Chen, Xiao-Yong

2013-06-01

Potatso National Park was the first national park in mainland China, preceded by the earlier Bitahai Nature Reserve. Located in the northwest of Yunnan and on the southeast of Qinghai-Tibet plateau, Potatso is a typical low latitude and high elevation wetland nature reserve, with large areas of coniferous forest around alpine lakes and both wetland and water area ecosystems. In August, 2011, we undertook a survey of crustaceans in the park, sampling lakes, ponds, streams, and rivers throughout Potatso. We found a total of 29 species (including varieties) belonging to 24 genera and 11 families. Notable discoveries include Parartemiopsis sp, Arctodiaptomus parvispinus and Simocephalus congener, which are the first examples of these species to be recorded in China. Likewise, Gammarus bitaensis is a unique crustacean found only in Potatso National Park and Thermocyclops dumonti and Gammarus paucispinus are both endemic species to northwestern Yunnan. The overall faunal characteristics of crustaceans in the park also revealed several things about Potatso: (1) Cosmopolitan and Palaearctic elements reach 48.27% and 37.93%, clearly showing the Palaearctic element as the dominant fauna; (2) most of the crustacean, such as Arctodiaptomus parvispinus and Gammarus, are typical alpine types, confirming that Potatso has feature typical of alpine and plateau fauna; and (3) the proportion of endemic and rare crustacean species in Potatso National Park is approximately 10%, suggesting that the Potatso National Park in particular and the northwest of Yunnan in general have a unique geological and evolutionary history.

Impacts of sanitation improvement on reduction of nitrogen discharges entering the environment from human excreta in China.

PubMed

Tong, Yindong; Bu, Xiaoge; Chen, Cen; Yang, Xi; Lu, Yiren; Liang, Huijiao; Liu, Maodian; Lin, Huiming; Zhang, Haoran; Lin, Yan; Zhou, Feng; Zhao, Shen; Wu, Tianyu; Mao, Guozhu; Zhang, Wei; Wang, Xuejun

2017-09-01

Identifying the sanitation efficacy in reducing contaminations entering the environment is an important step for water pollution controls and developing management strategies to further improve sanitation conditions. With continuous efforts in sanitation improvement during the past decade, reductions in discharges of aquatic nutrients are expected in China. In this study, we estimated the aquatic nitrogen discharges from human excreta in 31 provinces in China during 2006-2014. The results indicated that the nitrogen discharges entering the environment from human excreta are largely determined by both local population and sanitation conditions. In 2014, the nitrogen discharges from human excreta in the rural areas (2118(1219-3140) Gg per year) (median and 95% confidence interval) are higher than those in the urban areas (1485(626-2495) Gg per year). The significant relationship (R 2 =0.38, n=29) between the total nitrogen concentrations in lakes and corresponding local nitrogen discharges indicated that, the lakes might be potentially affected by the contaminant inputs from human excreta. The further calculations under two policy scenarios showed that through sanitation improvement, further reduction of nitrogen discharges from human excreta in the developed regions might be limited. The sanitation improvement in the less-developed regions, such as Tibet, Qinghai, and Ningxia, should be considered a priority due to the larger reduction potentials. Copyright © 2017 Elsevier B.V. All rights reserved.

Cyanobacteria in lakes on Yungui Plateau, China are assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use

PubMed Central

Liao, Jingqiu; Zhao, Lei; Cao, Xiaofeng; Sun, Jinhua; Gao, Zhe; Wang, Jie; Jiang, Dalin; Fan, Hao; Huang, Yi

2016-01-01

Plateau lakes are important ecosystems with diverse ecological functions. Cyanobacteria play a key role in plateau lakes as primary producers. However, they are threatening when dense blooms occur. Identifying cyanobacteiral biogeography and the mechanism of assembly processes shaping the distribution of cyanobacteria in plateau lakes is critical for understanding cyanobacterial ecology and applying it to lake management. In the present study, the biogeographic pattern and importance of neutral and niche processes in assembly of cyanobacteria in 21 lakes on Yungui Plateau, China were examined. Results showed that cyanobacteria exhibit unique biogeographic pattern, and most of them have a narrow habitat preference in plateau lakes. They were assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use, which explained 62.4% of the biological variation. Neutral processes were not at play. Water physicochemical property (key variables - dissolved oxygen, salinity, trophic status and pH) was the most dominant driver shaping its unique biogeographic pattern. Watershed land-use especially urban land, water body and agricultural land also exhibited a strong impact on cyanobacterial distribution, followed by lake morphology. As most of the cyanobacteiral genus detected in these plateau lakes were potential toxin-producers, this study indicated that in order to protect waters from toxic-bloom in the future, reducing nutrient loading and land-use practices are two practical approaches in plateau lake management. PMID:27819304

Cyanobacteria in lakes on Yungui Plateau, China are assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use

NASA Astrophysics Data System (ADS)

Liao, Jingqiu; Zhao, Lei; Cao, Xiaofeng; Sun, Jinhua; Gao, Zhe; Wang, Jie; Jiang, Dalin; Fan, Hao; Huang, Yi

2016-11-01

Plateau lakes are important ecosystems with diverse ecological functions. Cyanobacteria play a key role in plateau lakes as primary producers. However, they are threatening when dense blooms occur. Identifying cyanobacteiral biogeography and the mechanism of assembly processes shaping the distribution of cyanobacteria in plateau lakes is critical for understanding cyanobacterial ecology and applying it to lake management. In the present study, the biogeographic pattern and importance of neutral and niche processes in assembly of cyanobacteria in 21 lakes on Yungui Plateau, China were examined. Results showed that cyanobacteria exhibit unique biogeographic pattern, and most of them have a narrow habitat preference in plateau lakes. They were assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use, which explained 62.4% of the biological variation. Neutral processes were not at play. Water physicochemical property (key variables - dissolved oxygen, salinity, trophic status and pH) was the most dominant driver shaping its unique biogeographic pattern. Watershed land-use especially urban land, water body and agricultural land also exhibited a strong impact on cyanobacterial distribution, followed by lake morphology. As most of the cyanobacteiral genus detected in these plateau lakes were potential toxin-producers, this study indicated that in order to protect waters from toxic-bloom in the future, reducing nutrient loading and land-use practices are two practical approaches in plateau lake management.

Cyanobacteria in lakes on Yungui Plateau, China are assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use.

PubMed

Liao, Jingqiu; Zhao, Lei; Cao, Xiaofeng; Sun, Jinhua; Gao, Zhe; Wang, Jie; Jiang, Dalin; Fan, Hao; Huang, Yi

2016-11-07

Plateau lakes are important ecosystems with diverse ecological functions. Cyanobacteria play a key role in plateau lakes as primary producers. However, they are threatening when dense blooms occur. Identifying cyanobacteiral biogeography and the mechanism of assembly processes shaping the distribution of cyanobacteria in plateau lakes is critical for understanding cyanobacterial ecology and applying it to lake management. In the present study, the biogeographic pattern and importance of neutral and niche processes in assembly of cyanobacteria in 21 lakes on Yungui Plateau, China were examined. Results showed that cyanobacteria exhibit unique biogeographic pattern, and most of them have a narrow habitat preference in plateau lakes. They were assembled via niche processes driven by water physicochemical property, lake morphology and watershed land-use, which explained 62.4% of the biological variation. Neutral processes were not at play. Water physicochemical property (key variables - dissolved oxygen, salinity, trophic status and pH) was the most dominant driver shaping its unique biogeographic pattern. Watershed land-use especially urban land, water body and agricultural land also exhibited a strong impact on cyanobacterial distribution, followed by lake morphology. As most of the cyanobacteiral genus detected in these plateau lakes were potential toxin-producers, this study indicated that in order to protect waters from toxic-bloom in the future, reducing nutrient loading and land-use practices are two practical approaches in plateau lake management.

Variation of phytoplankton functional groups modulated by hydraulic controls in Hongze Lake, China.

PubMed

Tian, Chang; Pei, Haiyan; Hu, Wenrong; Hao, Daping; Doblin, Martina A; Ren, Ying; Wei, Jielin; Feng, Yawei

2015-11-01

Hongze Lake is a large, shallow, polymictic, eutrophic lake in the eastern China. Phytoplankton functional groups in this lake were investigated from March 2011 to February 2013, and a comparison was made between the eastern, western, and northern regions. The lake shows strong fluctuations in water level caused by monsoon rains and regular hydraulic controls. By application of the phytoplankton functional group approach, this study aims to investigate the spatial and temporal dynamics and analyze their influencing factors. Altogether, 18 functional groups of phytoplankton were identified, encompassing 187 species. In order to seek the best variable describing the phytoplankton functional group distribution, 14 of the groups were analyzed in detail using redundancy analysis. Due to the turbid condition of the lake, the dominant functional groups were those tolerant of low light. The predominant functional groups in the annual succession were D (Cyclotella spp. and Synedra acus), T (Planctonema lauterbornii), P (Fragilaria crotonensis), X1 (Chlorella vulgaris and Chlorella pyrenoidosa), C (Cyclotella meneghiniana and Cyclotella ocellata), and Y (Cryptomonas erosa). An opposite relationship between water level and the biomass of predominant groups was observed in the present study. Water level fluctuations, caused by monsoonal climate and artificial drawdown, were significant factors influencing phytoplankton succession in Hongze Lake, since they alter the hydrological conditions and influence light and nutrient availability. The clearly demonstrated factors, which significantly influence phytoplankton dynamics in Hongze Lake, will help government manage the large shallow lakes with frequent water level fluctuations.

[Prediction of potential geographic distribution of Lyme disease in Qinghai province with Maximum Entropy model].

PubMed

Zhang, Lin; Hou, Xuexia; Liu, Huixin; Liu, Wei; Wan, Kanglin; Hao, Qin

2016-01-01

To predict the potential geographic distribution of Lyme disease in Qinghai by using Maximum Entropy model (MaxEnt). The sero-diagnosis data of Lyme disease in 6 counties (Huzhu, Zeku, Tongde, Datong, Qilian and Xunhua) and the environmental and anthropogenic data including altitude, human footprint, normalized difference vegetation index (NDVI) and temperature in Qinghai province since 1990 were collected. By using the data of Huzhu Zeku and Tongde, the prediction of potential distribution of Lyme disease in Qinghai was conducted with MaxEnt. The prediction results were compared with the human sero-prevalence of Lyme disease in Datong, Qilian and Xunhua counties in Qinghai. Three hot spots of Lyme disease were predicted in Qinghai, which were all in the east forest areas. Furthermore, the NDVI showed the most important role in the model prediction, followed by human footprint. Datong, Qilian and Xunhua counties were all in eastern Qinghai. Xunhua was in hot spot areaⅡ, Datong was close to the north of hot spot area Ⅲ, while Qilian with lowest sero-prevalence of Lyme disease was not in the hot spot areas. The data were well modeled in MaxEnt (Area Under Curve=0.980). The actual distribution of Lyme disease in Qinghai was in consistent with the results of the model prediction. MaxEnt could be used in predicting the potential distribution patterns of Lyme disease. The distribution of vegetation and the range and intensity of human activity might be related with Lyme disease distribution.

Cooperation control strategies for China's cross-region pollution in a lake basin based on green reduction cost.

PubMed

Li, Changmin; Sun, Dong; Xie, Xiaoqiang; Xue, Jian

2016-05-01

The cross-region water pollution issue has always been the widespread concern around the world. It becomes especially critical for China due to the imbalance relates to environmental costs that have accompanied rapid growth of economy. Though the government makes great efforts to improve it, the potential for water pollution conflict is still great. We consider the problem of determining combined control strategies for China's cross-region lake pollution based on the environmental green costs. The problem is first formulated as a generalized bilevel mathematical program where the upper level consists in each region that reduces environmental green costs including three parts: the reduction cost, pollution permit trade cost and cost of environment damage, while the lower level is represented by pollution permit equilibrium market. Finally, we take an empirical analysis in Taihu lake. The numerical study shows that the minimum costs of both total and regional are obviously superior to the current processing costs, which provides theoretical basis for the price of emission permits. Today, China's rapid gross domestic product (GDP) growth has come at a very high cost, as real estate prices have skyrocketed, the wealth gap has widened, and environmental pollution has worsened. China's central government is urged to correct the GDP-oriented performance evaluation system that is used to judge administrative region leaders. The cross-region water pollution issue has become a troubling issue that urgently needs to be resolved in China. This paper will not only actively aid efforts to govern Lake Taihu and other cross-region valleys, but it will also provide a supplement for theoretical research on cross-region pollution issues.

Crew escape system test at Naval Weapons Center, China Lake, California

NASA Technical Reports Server (NTRS)

1988-01-01

As part of a crew escape system (CES) test program, a lifelike dummy is pulled by a tractor rocket from an airborne Convair-240 (C-240) aircraft at Naval Weapons Center, China Lake, California. A P-3 chase plane accompanies the C-240. The C-240 was modified with a space shuttle side hatch mockup for the tests which will evaluate candidate concepts developed to provide crew egress capability during Space Shuttle controlled gliding flight.

Hydromorphological processes of Dongting Lake in China between 1951 and 2014

NASA Astrophysics Data System (ADS)

Yu, Yawen; Mei, Xuefei; Dai, Zhijun; Gao, Jinjuan; Li, Jingbao; Wang, Jie; Lou, Yaying

2018-07-01

Under the impact of intensive anthropogenic activities and in the context of global climate change, the hydromorphological processes of most lakes around the world have changed dramatically. Here, based on hydrologic and topographic data, we analyzed secular variations in hydromorphological characteristics and their influencing factors at Dongting Lake, the second-largest freshwater lake in China. The entire time series (1951-2014) was divided into four subperiods based on the anthropogenic modifications of the Changjiang (Yangtze) River, including the construction of the Lower Jingjiang Cutoff Project and the operation of the Gezhou Dam (GD) and the Three Gorges Dam (TGD). The results indicated that there were obvious stepwise decreasing trends in the annual water discharge and suspended sediment discharge (SSD) from 1951 to 2014. Seasonal differences in water discharge and SSD over the recent 60 years exhibited a tendency of "less flooding during the flood season and more drying during the dry season". Meanwhile, the deposition-erosion budget of Dongting Lake shifted from a deposition rate of 120 × 106 t/yr from 1951 to 2003 to an erosion rate of 2 × 106 t/yr with the serious degradation of the Ouchi and Xiangjiang deltas after 2003. The hydrological processes of Dongting Lake are dominated by different anthropogenic activities at different stages. The Jingjiang Cutoff Project is the main driver of the decreases in water discharge and SSD from 1967 to 1980. The operation of the GD along the Changjiang River and other reservoirs, as well as land-use changes in the Dongting Lake basin, should be responsible for the hydrological variations from 1981 to 2003. The high sediment retention rate, geometric adjustment of the channel, and flow regulation induced by the operation of the TGD are the main drivers for the hydromorphological variations in Dongting Lake in 2004-2014.

Sedimentary Evidence of Environmental Degradation in Sanliqi Lake, Daye City (A Typical Mining City, Central China).

PubMed

Zeng, Linghan; Ning, Dongliang; Xu, Lei; Mao, Xin; Chen, Xu

2015-09-01

To reconstruct the history of environmental degradation in Sanliqi Lake (Daye City, central China), multiple proxies were analyzed in a sedimentary core which was dated using (137)Cs and spheroidal carbonaceous particles (SCPs). The results show that Sanliqi Lake has experienced serious degradation during the past 60 years, resulting from a large influx of metals and nutrients. Expansion of agricultural and industrial activities between 1945 and 1993 enhanced nutrient and metal enrichment, indicated by increases in metals, SCPs, magnetic susceptibility, total phosphorus, total nitrogen and total organic carbon. Further enrichment of Zn, Cd, Ni and Cr after 1993 was linked to a recent intensification of mining activities. Decreases in Cu and Pb after 2006 probably resulted from recent environmental remediation. This study verified the coupling between lake sediment pollution and human activities in Daye City during the past 60 years. The reconstructed history of lake pollution can provide reference information for continued restoration of Sanliqi Lake and other similar heavily polluted lakes in the developing regions.

Assessment of the Distribution, Sources and Potential Ecological Risk of Heavy Metals in the Dry Surface Sediment of Aibi Lake in Northwest China

PubMed Central

Abuduwaili, Jilili; Zhang, Zhao yong; Jiang, Feng qing

2015-01-01

The distribution, sources and potential ecological risk of heavy metals in the sediment of lakes in eastern China and other areas of the world that have undergone rapid economic development have been widely researched by scholars. However, this is not true for heavy metals in the sediment of rump lakes in the arid regions of China and world-wide. Because of this, we chose Aibi Lake to serve as a typical rump lake in an oasis in an arid area in northwest China for our study. Sediment samples were collected from the lake and then the quantities of the heavy metals Pb, Ni, Cd, Cu, Zn, Hg and Cr were measured. Then using a variety of statistical methods, we analyzed the distribution, sources, pollution status and the potential ecological risk of these metals. The results show that: (1) The amounts of the seven heavy metals all fell within the Second Soil National Standard, but the average and maximum values were all higher than the background values of Xinjiang in northwest China. (2) Multivariate statistical analysis determined that the Cd, Pb, Hg and Zn in the sediment were mainly derived from man-sources, and Cu, Ni, and Cr were mainly from the natural geological background. (3) Enrichment factor analysis and the geo-accumulation index evaluation method show that Cd, Hg and Pb in the surface sediment of the Aibi Lake were at low and partial pollution levels, while Zn, Cr, Ni and Cu were at no and low pollution levels. (4) Calculation of the potential ecological hazards index found that, among the seven tested heavy metals, Cd, Hg and Pb were the main potential ecological risk factors, and the contribution of each was 42.6%, 28.6%, and 24.0%, respectively. Cd is the main potential ecological risk factor, followed by Hg and Pb. This work revealed that recent economic development of the Aibi Lake Basin has negatively influenced the accumulation of heavy metals in the sediments of the lake, and, therefore, we should pay increasing attention to this problem and take

The effects of biotic and abiotic factors on the spatial heterogeneity of alpine grassland vegetation at a small scale on the Qinghai-Tibet Plateau (QTP), China.

PubMed

Wen, Lu; Dong, Shi Kui; Li, Yuan Yuan; Sherman, Ruth; Shi, Jian Jun; Liu, De Mei; Wang, Yan Long; Ma, Yu Shou; Zhu, Lei

2013-10-01

Understanding the complex effects of biotic and abiotic factors on the composition of vegetation is very important for developing and implementing strategies for promoting sustainable grassland development. The vegetation-disturbance-environment relationship was examined in degraded alpine grasslands in the headwater areas of three rivers on the Qinghai-Tibet Plateau in this study. The investigated hypotheses were that (1) the heterogeneity of the vegetation of the alpine grassland is due to a combination of biotic and abiotic factors and that (2) at a small scale, biotic factors are more important for the distribution of alpine vegetation. On this basis, four transects were set along altitudinal gradients from 3,770 to 3,890 m on a sunny slope, and four parallel transects were set along altitudinal gradients on a shady slope in alpine grasslands in Guoluo Prefecture of Qinghai Province, China. It was found that biological disturbances were the major forces driving the spatial heterogeneity of the alpine grassland vegetation and abiotic factors were of secondary importance. Heavy grazing and intensive rat activity resulted in increases in unpalatable and poisonous weeds and decreased fine forages in the form of sedges, forbs, and grasses in the vegetation composition. Habitat degradation associated with biological disturbances significantly affected the spatial variation of the alpine grassland vegetation, i.e., more pioneer plants of poisonous or unpalatable weed species, such as Ligularia virgaurea and Euphorbia fischeriana, were found in bare patches. Environmental/abiotic factors were less important than biological disturbances in affecting the spatial distribution of the alpine grassland vegetation at a small scale. It was concluded that rat control and light grazing should be applied first in implementing restoration strategies. The primary vegetation in lightly grazed and less rat-damaged sites should be regarded as a reference for devising vegetation

Heavy metal pollution assessment, source identification, and health risk evaluation in Aibi Lake of northwest China.

PubMed

Zhaoyong, Zhang; Xiaodong, Yang; Shengtian, Yang

2018-01-08

This study sought to analyze heavy metal (Pb, Zn, Cu, Ni, Mn, and Fe) pollution status in the waters of Aibi Lake in northwest China through the use of an applied comprehensive pollution index, health risk model, and multivariate statistical analyses in combination with the lake's land use types. Results showed that (1) the maximum (average) values of the heavy metals Pb, Zn, Cu, Ni, Mn, and Fe were 0.0644 (0.0123), 0.0006 (0.0002), 0.0009 (0.0032), 0.1235 (0.0242), 0.0061 (0.0025), and 0.0222 (0.0080) μg/L, respectively. Among these, in all the samples, Pb and Ni exceeded the standard and acceptable values put forth by the World Health Organization by 21.13 and 25.67%, respectively. Ni also exceeded (30.16%) the third grade of the Environmental Quality Standards for Surface Water of China. The levels of the six heavy metals were all within the fishery and irrigation water quality standard ranges in China. (2) The average values for single pollution index of heavy metals Pb, Zn, Cu, Ni, Mn, and Fe were 1.000, 0.0006, 0.0009, 3.000, 0.060, and 0.070, respectively, among which Ni levels indicated moderate to significant pollution, while others indicated healthy levels. (3) Health risk evaluation showed that the R n values for Pb, Zn, Cu, Mn, and Fe were 1.8 × 10 -4 , 5.33 × 10 -9 , 4.80 × 10 -7 , 1.08 × 10 -6 , and 2.51 × 10 -7  a -1 , respectively, of which, in all samples, Pb and Ni contents all exceeded the maximum acceptable risk levels according to the International Commission on Radiological Protection (ICRP) as well as the U.S. Environment Protection Agency. (4) Combining with multivariate statistical analyses along with the land use distribution within the lake basin, Pb, Zn, Cu, Ni, and Mn were mainly influenced by the agriculture production and emission from urban lives and traffics, and Fe mainly originated from the natural environment. The results of this research can provide reference values for heavy metal pollution

Direct versus indirect climate controls on Holocene diatom assemblages in a sub-tropical deep, alpine lake (Lugu Hu, Yunnan, SW China)

NASA Astrophysics Data System (ADS)

Wang, Qian; Yang, Xiangdong; Anderson, Nicholas John; Dong, Xuhui

2016-07-01

The reconstruction of Holocene environmental changes in lakes on the plateau region of southwest China provides an understanding of how these ecosystems may respond to climate change. Fossil diatom assemblages were investigated from an 11,000-year lake sediment core from a deep, alpine lake (Lugu Hu) in southwest China, an area strongly influenced by the southwest (or the Indian) summer monsoon. Changes in diatom assemblage composition, notably the abundance of the two dominant planktonic species, Cyclotella rhomboideo-elliptica and Cyclostephanos dubius, reflect the effects of climate variability on nutrient dynamics, mediated via thermal stratification (internal nutrient cycling) and catchment-vegetation processes. Statistical analyses of the climate-diatom interactions highlight the strong effect of changing orbitally-induced solar radiation during the Holocene, presumably via its effect on the lake's thermal budget. In a partial redundancy analysis, climate (solar insolation) and proxies reflecting catchment process (pollen percentages, C/N ratio) were the most important drivers of diatom ecological change, showing the strong effects of climate-catchment-vegetation interactions on lake functioning. This diatom record reflects long-term ontogeny of the lake-catchment ecosystem and suggests that climatic changes (both temperature and precipitation) impact lake ecology indirectly through shifts in thermal stratification and catchment nutrient exports.

Origin and character of loesslike silt in the southern Qinghai-Xizang (Tibet) Plateau, China

USGS Publications Warehouse

Pewe, T.L.; Tungsheng, Liu; Slatt, R.M.; Bingyuan, Li

1995-01-01

Retransported, tan, loesslike silt is widespread in the southern Qinghai-Xizang (Tibet) Plateau. The silt occurs mainly in the lowlands and lower slopes and is absent on steep slopes and active flood plains. The silt covers most alluvial fans and is interbedded with the sand and gravel of the fans. It is well exposed in the agricultural fields on low terraces in the valleys and in the steep-walled scarps of dissected valley fill. The silt is primary loess on the low hill tops; however, the poorly to well-stratified loesslike silt on the lower slopes and in valley bottoms of the major river valleys is retransported loess. It probably was originally deposited by winds blowing across broad vegetation-free flood plains.

Land Desertification and it’s Control in Gonghe Basin of Qinghai Plateau, China

NASA Astrophysics Data System (ADS)

Zhang, D.; Gao, S.; Lu, R.

2009-12-01

Land desertification is an important environmental and social-economic problems that threatening people’s living conditions and impacting social sustainable development. The Gonghe basin in Qinghai Plateau is a fragile cold alpine area which is one of the places seriously threatened by desertification in China. This paper selected Gonghe basin as a study area to study land sandy desertification and its controlling measures. The engineering measures for sandy desertification control include setting clay sand barrier, Salix cheilophila sand barrier, Tamarix sand barrier, Artemisia sand barrier and straw-checker sand-barriers to fix dunes; the biological measures include closure for natural vegetation recovery, direct seeding forestation, transplanting seedlings, and so on. The combination of engineering and biologic measures can fix dunes 2~3 years earlier than the common single measure; and the costs were basically identical. A synthesized evaluation system established based on experimental results and experience in recent years indicated that the effectiveness of the four kinds of sand barrier for prevention and control of sand in study area were: Tamarix sand barrier > Artemisia sand barrier > clay sand barrier > straw-checker sand-barriers. In addition, different optimized management model can be selected according to local material and geographical place. New plants such as Salix cheilophila and Tamarix, which are available in study area, can change from dead sand barrier to live one set in proper seasons, changing engineering measure to biological one directly speeds the progress of forestation and dunes fixation. In addition, we developed new technique of deep planting Salix cheilophila and Tamarix with their long stem, which can effectively resist drought. We found that it had lower cost and higher live rate, and has a better sand prevention effect than deep planting of Poplar. Finally we choose the optimize management model as follows: Artemisia direct

Modeling and Simulation of the Gonghe geothermal field (Qinghai, China) Constrained by Geophysical

NASA Astrophysics Data System (ADS)

Zeng, Z.; Wang, K.; Zhao, X.; Huai, N.; He, R.

2017-12-01

The Gonghe geothermal field in Qinghai is important because of its variety of geothermal resource types. Now, the Gonghe geothermal field has been a demonstration area of geothermal development and utilization in China. It has been the topic of numerous geophysical investigations conducted to determine the depth to and the nature of the heat source, and to image the channel of heat flow. This work focuses on the causes of geothermal fields used numerical simulation method constrained by geophysical data. At first, by analyzing and inverting an magnetotelluric (MT) measurements profile across this area we obtain the deep resistivity distribution. Using the gravity anomaly inversion constrained by the resistivity profile, the density of the basins and the underlying rocks can be calculated. Combined with the measured parameters of rock thermal conductivity, the 2D geothermal conceptual model of Gonghe area is constructed. Then, the unstructured finite element method is used to simulate the heat conduction equation and the geothermal field. Results of this model were calibrated with temperature data for the observation well. A good match was achieved between the measured values and the model's predicted values. At last, geothermal gradient and heat flow distribution of this model are calculated(fig.1.). According to the results of geophysical exploration, there is a low resistance and low density region (d5) below the geothermal field. We recognize that this anomaly is generated by tectonic motion, and this tectonic movement creates a mantle-derived heat upstream channel. So that the anomalous basement heat flow values are higher than in other regions. The model's predicted values simulated using that boundary condition has a good match with the measured values. The simulated heat flow values show that the mantle-derived heat flow migrates through the boundary of the low-resistance low-density anomaly area to the Gonghe geothermal field, with only a small fraction

Cryptosporidium Contamination and Attributed Risks in Yunlong Lake in Xuzhou, China

PubMed Central

Kong, Yadong; Yuan, Tao; Niu, Jinghui; Li, Zhaoji; Yang, Baisong

2017-01-01

Swimming in surface water bodies (e.g., lakes, rivers) can expose the human body to substantial risk of infection by Cryptosporidium. These findings are from a one-year investigation on the occurrence and distribution of the protozoan parasite Cryptosporidium in Yunlong Lake, Xuzhou, China. Cryptosporidium oocysts were detected by immunofluorescence microscopy. From January to November of 2015, 180 samples (120 water samples and 60 sediment samples) were collected and analyzed. Among them, 42 (35%) water samples and 28 (47%) sediment samples tested positive for Cryptosporidium. The concentration of Cryptosporidium oocysts in the water samples was 0–8/10 L and 0–260/g in sediment samples. Results revealed that July was the highest risk period for both swimming and diving with an estimated probability of infection from swimming of greater than 18 per 10,000 swim sessions. It was concluded that swimming or diving in Yunlong Lake has a higher risk of Cryptosporidium infection than the acceptable risk level set by the United States Environmental Protection Agency. Thus, regular monitoring of water quality in recreation water bodies is strongly recommended. PMID:28386287

Spatial and temporal distribution and sources of polycyclic aromatic hydrocarbons in sediments of Taihu Lake, eastern China.

PubMed

Tang, Zhi; Guo, Jianyang; Liao, Haiqing; Zhao, Xiaoli; Wu, Fengchang; Zhu, Yuanrong; Zhang, Liang; Giesy, John P

2015-04-01

Spatial and temporal distributions of concentrations of polycyclic aromatic hydrocarbons (PAHs) in surface sediments and dated sediment core from Taihu Lake in eastern China were determined. The sum of concentrations of PAHs (sum of total 16 USEPA priority PAH (∑PAHs)) of the entire Taihu Lake ranged from 2.9 × 10(2) to 8.4 × 10(2) ng/g dry mass (dm). Concentrations of ∑PAHs in surface sediments near more urbanized regions of the lake shore were greater than those in areas more remote from the urban centers. Temporal trends in concentrations of ∑PAHs ranged from 5.1 × 10(2) to 1.5 × 10(3) ng/g dm, increasing from deeper layers to surface sediments with some fluctuations, especially in the past three decades after the inception of China's Reform and Opening Up Policy, in which China's economy and urbanization underwent rapid development. Forensic analysis of surface sediments indicates that PAHs originated primarily from combustion of grass/wood/coal except for the special function water area, which was most likely influenced by petroleum products of traveling vessels. Vertical profiles of relative concentrations of PAHs suggested that the contribution of lesser-molecular-weight PAHs was gradually decreasing, while due to the heavier consumption of petroleum products, the proportion of greater-molecular-weight PAHs was increasing. When assessed by use of the rather conservative, apparent effect threshold method, concentrations of ∑PAHs in sediments from most locations in Taihu Lake are predicted to pose little risk of harm to benthic invertebrates.

Phosphorus and Defoliation Interact and Improve the Growth and Composition of the Plant Community and Soil Properties in an Alpine Pasture of Qinghai-Tibet Plateau.

PubMed

Qi, Juan; Nie, Zhongnan; Jiao, Ting; Zhang, Degang

2015-01-01

Pasture degradation caused by overgrazing and inappropriate fertiliser management is a major production and environmental threat in Qinghai-Tibet Plateau. Previous research has focused on the effects of mixed nitrogen (N) and phosphorus (P) fertiliser and reduced grazing pressure on the plant community of the grassland; however, the role of P and how it interacts with various defoliation (the process of the complete or partial removal of the above-ground parts of plants by grazing or cutting) intensities on the plant and soil of the grassland ecosystem have not been quantified. A field experiment was conducted to quantify how P application in combination of defoliation pressure could impact the dynamic change of the plant and soil in a native alpine grassland ecosystem of the Qinghai-Tibet Plateau, China, from May 2012 to September 2014. A split-plot design with 4 replicates and repeated measures was used to determine the growth and composition of plant community and soil physical and chemical properties under various levels of P fertiliser and defoliation intensity. The results showed that applying 20 kg P/ha increased the herbage yield of Melissitus ruthenica by 68% and total pasture yield by 25%. Close defoliation favoured the growth and plant frequency of the shorter species, whereas lax defoliation favoured that of the taller plant species. Medium P rate and cutting to 3 cm above ground gave an overall best outcome in pasture yield, quality and frequency and soil moisture and nutrient concentration. Application of P fertiliser with a moderate defoliation pressure to promote legume growth and N fixation has the potential to achieve multiple benefits in increasing pasture and livestock production and improving environmental sustainability in the alpine pasture of Qinghai-Tibet Plateau, a fragile and P-deficient ecosystem zone in China and its western neighbouring countries.

Phosphorus and Defoliation Interact and Improve the Growth and Composition of the Plant Community and Soil Properties in an Alpine Pasture of Qinghai-Tibet Plateau

PubMed Central

Qi, Juan; Nie, Zhongnan; Jiao, Ting; Zhang, Degang

2015-01-01

Pasture degradation caused by overgrazing and inappropriate fertiliser management is a major production and environmental threat in Qinghai-Tibet Plateau. Previous research has focused on the effects of mixed nitrogen (N) and phosphorus (P) fertiliser and reduced grazing pressure on the plant community of the grassland; however, the role of P and how it interacts with various defoliation (the process of the complete or partial removal of the above-ground parts of plants by grazing or cutting) intensities on the plant and soil of the grassland ecosystem have not been quantified. A field experiment was conducted to quantify how P application in combination of defoliation pressure could impact the dynamic change of the plant and soil in a native alpine grassland ecosystem of the Qinghai-Tibet Plateau, China, from May 2012 to September 2014. A split-plot design with 4 replicates and repeated measures was used to determine the growth and composition of plant community and soil physical and chemical properties under various levels of P fertiliser and defoliation intensity. The results showed that applying 20 kg P/ha increased the herbage yield of Melissitus ruthenica by 68% and total pasture yield by 25%. Close defoliation favoured the growth and plant frequency of the shorter species, whereas lax defoliation favoured that of the taller plant species. Medium P rate and cutting to 3 cm above ground gave an overall best outcome in pasture yield, quality and frequency and soil moisture and nutrient concentration. Application of P fertiliser with a moderate defoliation pressure to promote legume growth and N fixation has the potential to achieve multiple benefits in increasing pasture and livestock production and improving environmental sustainability in the alpine pasture of Qinghai-Tibet Plateau, a fragile and P-deficient ecosystem zone in China and its western neighbouring countries. PMID:26513363

Village-based spatio-temporal cluster analysis of the schistosomiasis risk in the Poyang Lake Region, China.

PubMed

Xia, Congcong; Bergquist, Robert; Lynn, Henry; Hu, Fei; Lin, Dandan; Hao, Yuwan; Li, Shizhu; Hu, Yi; Zhang, Zhijie

2017-03-08

The Poyang Lake Region, one of the major epidemic sites of schistosomiasis in China, remains a severe challenge. To improve our understanding of the current endemic status of schistosomiasis and to better control the transmission of the disease in the Poyang Lake Region, it is important to analyse the clustering pattern of schistosomiasis and detect the hotspots of transmission risk. Based on annual surveillance data, at the village level in this region from 2009 to 2014, spatial and temporal cluster analyses were conducted to assess the pattern of schistosomiasis infection risk among humans through purely spatial (Local Moran's I, Kulldorff and Flexible scan statistic) and space-time scan statistics (Kulldorff). A dramatic decline was found in the infection rate during the study period, which was shown to be maintained at a low level. The number of spatial clusters declined over time and were concentrated in counties around Poyang Lake, including Yugan, Yongxiu, Nanchang, Xingzi, Xinjian, De'an as well as Pengze, situated along the Yangtze River and the most serious area found in this study. Space-time analysis revealed that the clustering time frame appeared between 2009 and 2011 and the most likely cluster with the widest range was particularly concentrated in Pengze County. This study detected areas at high risk for schistosomiasis both in space and time at the village level from 2009 to 2014 in Poyang Lake Region. The high-risk areas are now more concentrated and mainly distributed at the river inflows Poyang Lake and along Yangtze River in Pengze County. It was assumed that the water projects including reservoirs and a recently breached dyke in this area were partly to blame. This study points out that attempts to reduce the negative effects of water projects in China should focus on the Poyang Lake Region.

The Relationship between Phytoplankton Evenness and Copepod Abundance in Lake Nansihu, China

PubMed Central

Tian, Wang; Zhang, Huayong; Zhao, Lei; Xu, Xiang; Huang, Hai

2016-01-01

The relationship between biodiversity and ecosystem functioning is a central issue in ecology. Previous studies have shown that producer diversity can impact the consumer community via predator-prey interactions. However, direct observations of this relationship remain rare, in particular for aquatic ecosystems. In this research, the relationship between phytoplankton diversity (species richness and evenness) and the abundance of copepods was analyzed in Lake Nansihu, a meso-eutrophic lake in China. The results showed that copepods abundance was significantly decreased with increasing phytoplankton evenness throughout the year. However, both species richness and phytoplankton biomass showed no significant relationship with the abundance of copepods. Canonical correspondence analysis revealed that phytoplankton evenness was negatively correlated with Thermocyclops kawamurai, Cyclops vicinus, Eucyclops serrulatus, Mesocyclops leuckarti, Sinocalanus tenellus, Sinocalanus dorrii, Copepods nauplius, but positively correlated with many Cyanophyta species (Chroococcus minutus, Dactylococcopsis acicularis, Microcystis incerta, Merismopedia tenuissima, Merismopedia sinica and Lyngbya limnetica). Based on our results, phytoplankton evenness was a better predictor of copepods abundance in meso-eutrophic lakes. These results provide new insights into the relationship between diversity and ecosystem functioning in aquatic ecosystems. PMID:27589782

The Relationship between Phytoplankton Evenness and Copepod Abundance in Lake Nansihu, China.

PubMed

Tian, Wang; Zhang, Huayong; Zhao, Lei; Xu, Xiang; Huang, Hai

2016-08-31

The relationship between biodiversity and ecosystem functioning is a central issue in ecology. Previous studies have shown that producer diversity can impact the consumer community via predator-prey interactions. However, direct observations of this relationship remain rare, in particular for aquatic ecosystems. In this research, the relationship between phytoplankton diversity (species richness and evenness) and the abundance of copepods was analyzed in Lake Nansihu, a meso-eutrophic lake in China. The results showed that copepods abundance was significantly decreased with increasing phytoplankton evenness throughout the year. However, both species richness and phytoplankton biomass showed no significant relationship with the abundance of copepods. Canonical correspondence analysis revealed that phytoplankton evenness was negatively correlated with Thermocyclops kawamurai, Cyclops vicinus, Eucyclops serrulatus, Mesocyclops leuckarti, Sinocalanus tenellus, Sinocalanus dorrii, Copepods nauplius, but positively correlated with many Cyanophyta species (Chroococcus minutus, Dactylococcopsis acicularis, Microcystis incerta, Merismopedia tenuissima, Merismopedia sinica and Lyngbya limnetica). Based on our results, phytoplankton evenness was a better predictor of copepods abundance in meso-eutrophic lakes. These results provide new insights into the relationship between diversity and ecosystem functioning in aquatic ecosystems.

Two new species of the nemourid genus Amphinemura (Plecoptera: Nemouridae) from China.

PubMed

Li, Weihai; DU, Kaishu; Yang, Ding

2017-04-19

Two new species of the nemourid genus Amphinemura, A. dabanshana sp. nov. and A. kuankuoshui sp. nov., are described from Qinghai and Guizhou provinces of China. These two new species are compared with related taxa. The types of the new species are deposited in the Entomological Museum of China Agricultural University, Beijing and Henan Institute of Science and Technology, Xinxiang, respectively.

Tracers Show Ecohydrologic Influences on Runoff Generation Components at the Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Liu, H.; Liu, J.; Peng, A.; Gu, W.; Wang, W.; Gao, F.

2017-12-01

In order to learn more about the critical zone ecohydrological dynamics at the Qinghai-Tibet Plateau, a research on the identification of runoff components using tracers was carried out in the Niyang River upstream, a tributary of the Yalung Zangbo River. In this study, four basins with the areas of 182, 216, 243, 213 km2 which are embed in a larger basin were sampled at altitudes between 3667 to 6140 m. The types of land use in the basins mainly include forest land, grassland and glacier. River water and precipitation were sampled monthly, while spring water, glacial ice, soil, and plants were sampled seasonally. Soil and plant samples were taken along the valleys with spatial interval of about 5 km. Soil and plant waters were extracted via cryogenic vacuum distillation method, and then analyzed for isotopes and ions. Preliminary results show that the δD and δ18O of the precipitation water spread approximately along the LMWL of the Namucuo Lake near Lasa city, which varied according to altitude. Stem water δD and δ18O from different elevations and tree species also varied regularly, albeit with no apparent relationship to recent precipitation. It appears that trees utilized fissure water and soil water formed by precipitation. Future efforts will involve (1) an expanded sampling strategy across basins, and (2) a series of experiments on the Hydrohill catchment in the Chuzhou Experimental Facility, whereby an improved understanding of K+, Na+, Ca2+ and Mg2+ export dynamics could aid in much better description and modeling of Niyang River runoff composition and generation. This research is funded by the NSFC project 91647111 and 91647203, which are included in the Runoff Change and its Adaptive Management in the Major Rivers in Southwestern China Major Research Plan.

[Quantitative evaluation of resource and environment pressure in Qinghai Province, China based on footprint family].

PubMed

Ma, Cai Hong; Zhao, Jing

2016-04-22

In order to effectively evaluate the influence of human activities on the resource and environment, this paper constructed an resource and environment pressure evaluation system based on footprint family, and calculated the ecological footprint, carbon footprint, water footprint, and resource and environment pressure in Qinghai Province. The results showed that from 1990 to 2013, the ecological footprint per capita in Qinghai Province increased from 1.32 hm 2 to 3.32 hm 2 , and biological capacity per capita decreased from 2.33 hm 2 to 2.07 hm 2 . Since 2006 there was ecological deficit. However, the biomass surplus existed during 1990-2013. The carbon footprint per capita increased from 5.82 t to 15.85 t, which had been more than 7.93 times of the target to address climate change. The water footprint per capita decreased from 967.67 m 3 to 732.05 m 3 . Since 1990, the ecological pressure was at low grade (1 b ), greenhouse gas (GHG) emissions pressure was enhanced from low grade (1 b ) to above-average grade (2 b ), the water pressure was at very low grade (1 a ), the resource and environment pressure increased from very low grade (1 a ) to low grade (1 b ). The rate of contribution of ecological pressure and water resource pressure to resources and environment pressure gradually decreased, whereas, the rate of contribution of GHG emission pressure to resources and environment pressure gradually increased. The resource and environment pressure had spatial heterogeneity. In 2013, it was at very high grade (3 b ) in Xining City, at above-average grade (2 b ) in Haidong City, at below-average grade (2 a ) in Haixi State and atvery low grade (1 a ) in the rest regions. The main resource and environment pressure source also had obvious spatial heterogeneity. In future, differentiation strategies should be taken in the decompression progress.

O3, SO2, NO2, and UVB measurements in Beijing and Baseline Station of northwestern part of China

NASA Technical Reports Server (NTRS)

Guo, Song; Zhou, Xiuji; Zhang, Xiachun

1994-01-01

A MKII Brewer ozone spectrometer was used in Beijing from Oct. 1990 to June 1991 to measure O3, SO2 and UVB radiation. And since Nov. 1991 a new MKIV Brewer spectrometer, which can take the measurements of O3, SO2, NO2 and UVB radiation, has been set up in Beijing. The MKII Brewer spectrometer was moved to Qinghai baseline station which is on the Qinghai-tibetean plateau in the northwestern part of China. Both the data in Beijing and Qinghai baseline station has been analyzed and some results will be shown here along with the ozone profiles botained through the Umkehr program given by AES of Canada for the Brewer ozone spectrometer.

Eutrophication assessment and management methodology of multiple pollution sources of a landscape lake in North China.

PubMed

Chen, Yanxi; Niu, Zhiguang; Zhang, Hongwei

2013-06-01

Landscape lakes in the city suffer high eutrophication risk because of their special characters and functions in the water circulation system. Using a landscape lake HMLA located in Tianjin City, North China, with a mixture of point source (PS) pollution and non-point source (NPS) pollution, we explored the methodology of Fluent and AQUATOX to simulate and predict the state of HMLA, and trophic index was used to assess the eutrophication state. Then, we use water compensation optimization and three scenarios to determine the optimal management methodology. Three scenarios include ecological restoration scenario, best management practices (BMPs) scenario, and a scenario combining both. Our results suggest that the maintenance of a healthy ecosystem with ecoremediation is necessary and the BMPs have a far-reaching effect on water reusing and NPS pollution control. This study has implications for eutrophication control and management under development for urbanization in China.

Monitoring potential geographical distribution of four wild bird species in China

NASA Astrophysics Data System (ADS)

Dai, S.; Feng, D.; Xu, B.

2015-12-01

The outbreak of highly pathogenic avian influenza (HPAI) of the H5N1 subtype in wild birds and poultry have caught worldwide attention. To explore the association between wild bird migration and avian influenza virus transmission, we monitored potential geographical distribution of four wild bird species that might carry the avian influenza viruses in China. They are Bar-headed geese (Anser indicus), Ruddy Shelduck (Tadorna ferruginea), Whooper Swan (Cygnus cygnus) and Black-headed Gull (Larus ridibundus). They served as major reservoir of the avian influenza viruses. We used bird watching records with the precise latitude/longitude coordinates from January 2002 to August 2014, and environmental variables with a pixel resolution of 5 km × 5 km from 2002 to 2014. The study utilized maximum entropy (MaxEnt) model based on ecological niche model approaches, and got the following results: 1) MaxEnt model have good discriminatory ability with the area under the curve (AUC) of the receiver operating curve (ROC) of 0.86-0.97; 2) The four wild bird species were estimated to concentrate in the North China Plain, the middle and lower region of the Yangtze River, Qinghai Lake, Tianshan Mountain and Tarim Basin, part of Tibet Plateau, and Hengduan Mountains; 3) Radiation and the minimum temperature were found to provide the most significant information. Our findings will help to understand the spread of avian influenza viruses by wild bird migration in China, which benefits for effective monitoring strategies and prevention measures.

Application of UTCI in China from tourism perspective

NASA Astrophysics Data System (ADS)

Ge, Quansheng; Kong, Qinqin; Xi, Jianchao; Zheng, Jingyun

2017-05-01

This study uses ERA-Interim reanalysis data and the Universal Thermal Climate Index (UTCI) to investigate the spatial pattern of thermal bioclimatic conditions in China. Our results show that the annual UTCI increases with decreasing latitude throughout most of China. Areas that experience "no thermal stress" are located southeast of the line formed by the Yanshan Mountains, Taihang Mountains, the southern edge of the Loess Plateau, and the eastern edge of the Qinghai-Tibet Plateau, with an area of 312.83e4 km2. During spring and autumn, the UTCI distribution is similar to the annual distribution. During summer, areas with "no thermal stress" cover the largest area (563.55e4 km2), including northern and southwestern China; in contrast, during winter, areas with "no thermal stress" only occur south of the Nanling Mountains. The annual number of days with "no thermal stress" increases from north to south in central and eastern China, exceeding 200 days in the Sichuan Basin, the southeastern coastal regions and the Yungui Plateau. The minimum and maximum values occur on the Qinghai-Tibet Plateau (≤10 days) and the southern Yungui Plateau (>280 days). Seasonal analysis indicates that there are over 70 days with "no thermal stress" in the Sichuan Basin, the Yungui Plateau and the middle and lower reaches of the Yangtze River during spring and autumn, while there are more than 80 days in northern and southwestern China during summer and over 80 days in areas south of the Nanling Mountains during winter. The results of this study can be helpful for optimization of the tourism industry and tourism destinations development in China.

Genetic variation and phylogenetic relationships of the ectomycorrhizal Floccularia luteovirens on the Qinghai-Tibet Plateau.

PubMed

Xing, Rui; Gao, Qing-Bo; Zhang, Fa-Qi; Fu, Peng-Cheng; Wang, Jiu-Li; Yan, Hui-Ying; Chen, Shi-Long

2017-08-01

Floccularia luteovirens, as an ectomycorrhizal fungus, is widely distributed in the Qinghai-Tibet Plateau. As an edible fungus, it is famous for its unique flavor. Former studies mainly focus on the chemical composition and genetic structure of this species. However, the phylogenetic relationship between genotypes remains unknown. In this study, the genetic variation and phylogenetic relationship between the genotypes of F. luteovirens in Qinghai-Tibet Plateau was estimated through the analysis on two protein-coding genes (rpb1 and ef-1α) from 398 individuals collected from 24 wild populations. The sample covered the entire range of this species during all the growth seasons from 2011 to 2015. 13 genotypes were detected and moderate genetic diversity was revealed. Based on the results of network analysis, the maximum likelihood (ML), maximum parsimony (MP), and Bayesian inference (BI) analyses, the genotypes H-1, H-4, H-6, H-8, H-10, and H-11 were grouped into one clade. Additionally, a relatively higher genotype diversity (average h value is 0.722) and unique genotypes in the northeast edge of Qinghai- Tibet plateau have been found, combined with the results of mismatch analysis and neutrality tests indicated that Southeast Qinghai-Tibet plateau was a refuge for F. luteovirens during the historical geological or climatic events (uplifting of the Qinghai-Tibet Plateau or Last Glacial Maximum). Furthermore, the present distribution of the species on the Qinghai-Tibet plateau has resulted from the recent population expansion. Our findings provide a foundation for the future study of the evolutionary history and the speciation of this species.

The bumblebees of North China (Apidae, Bombus Latreille).

PubMed

An, Jiandong; Huang, Jiaxing; Shao, Youquan; Zhang, Shiwen; Wang, Biao; Liu, Xinyu; Wu, Jie; Williams, Paul H

2014-07-08

Bumblebees are important pollinators for wild flowers and agricultural crops. North China is a region of varied geomorphology and vegetation, with plateaus, plains, mountains and deserts, and is part of the greatest hotspot of bumblebee diversity worldwide. We report on a field survey of the bumblebees of North China made between 2005-2012. A sample of 21,636 bumblebee specimens are assigned to 76 species. One older specimen held in London added one more species to this list. Together, these 77 species represent 10 subgenera of the genus Bombus. Seven species are recorded from North China for the first time: B. (St.) distinguendus, B. (Th.) anachoreta, B. (Th.) pseudobaicalensis, B. (Th.) exil, B. (Ps.) campestris, B. (Pr.) infirmus and B. (Ag.) validus. We provide identification keys for both males and females, photographs of the common colour patterns, and distribution maps for all species. We describe variation in local species richness and abundance, and list the food plants used by bumblebees in North China. The most abundant 10 bumblebee species are: B. (Ml.) pyrosoma, B. (Bo.) lantschouensis, B. (Bo.) patagiatus, B. (St.) melanurus, B. (Sb.) sibiricus, B. (Bo.) ignitus, B. (Th.) hedini, B. (Pr.) picipes, B. (Mg.) trifasciatus and B. (Mg.) longipes. Bumblebees are distributed widely within North China, from low elevations near the edge of the North-China plain to high elevations at the edge of the east Qinghai-Tibetan plateau (65-4011 m). The highest species richness is found in meadows of the high elevation east Qinghai-Tibetan plateau and in forests of the Qilianshan mountains in southwestern Gansu. The 337 food plant species recorded here belong to 49 families, showing that bumblebees play an important role in interconnecting agricultural and natural ecosystems in North China. 

Inorganic pollution around the Qinghai-Tibet Plateau: An overview of the current observations.

PubMed

Wu, Jun; Duan, Dongping; Lu, Jian; Luo, Yongming; Wen, Xiaohu; Guo, Xiaoying; Boman, Brian J

2016-04-15

The Qinghai-Tibet Plateau is the highest geographical unit in the world. Thus, it serves an important role in evaluating long-term ecologic conditions and environmental status and changes over time. This study summarizes major and trace element concentrations in biota and in water and soil. It also pays attention to gaseous pollutant and particle concentrations in air around the Qinghai-Tibet Plateau. The degree of soil heavy metal contamination and the water heavy metal hazard index were respectively evaluated. The contamination degrees of two sampling areas around the Qinghai-Tibet Plateau reached extremely high levels with soil mCd (modified degree of contamination) values exceeding 20. Surprisingly, over 54% of sampling areas showed moderate or more serious soil contamination degree (mCd>1.5). Moreover, the hazard indexes of two important rivers were 1.56 and 7.59, reaching unacceptable level. The potential risk might be beyond our expectation. Therefore, it should be an urgent and top priority to identify and confirm possible pollution sources around the Qinghai-Tibet Plateau. Then, it is imperative to implement feasible and effective environmental quality control strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

[The pathogenic ecology research on plague in Qinghai plateau].

PubMed

Dai, Rui-xia; Wei, Bai-qing; Li, Cun-xiang; Xiong, Hao-ming; Yang, Xiao-yan; Fan, Wei; Qi, Mei-ying; Jin, Juan; Wei, Rong-jie; Feng, Jian-ping; Jin, Xing; Wang, Zu-yun

2013-12-01

To study the pathogenic ecology characteristics of plague in Qinghai plateau. Applied molecular biology techniques, conventional technologies and geographic information system (GIS) to study phenotypic traits, plasmid spectrum, genotype, infected host and media spectrum etc.of 952 Yersinia pestis strains in Qinghai plateau plague foci, which were separated from different host and media in different regions during 1954 to 2012. The ecotypes of these strains were Qingzang plateau (91.49%, 871/952),Qilian mountain (6.41%, 61/952) and Microtus fuscus (1.26%, 12/952).83.6% (796/952) of these strains contained all the 4 virulence factors (Fr1, Pesticin1,Virulence antigen, and Pigmentation), 93.26% (367/392) were velogenic strains confirmed by virulence test.725 Yersinia pestis strains were separated from Qinghai plateau plague foci carried 9 kinds of plasmid, among which 713 strains from Marmot himalayan plague foci carried 9 kinds of plasmid, the Mr were 6×10(6), 7×10(6), 23×10(6), 27×10(6), 30×10(6), 45×10(6), 52×10(6), 65×10(6) and 92×10(6) respectively. 12 Yersinia pestis strains were separated from Microtus fuscus plague foci carried only 3 kinds of plasmid, the Mr were 6×10(6), 45×10(6), 65×10(6). Meanwhile, the strains carrying large plasmid (52×10(6), 65×10(6) and 92×10(6)) were only distributed in particular geographical location, which had the category property. The research also confirmed that 841 Yersinia pestis strains from two kinds of plague foci in Qinghai plateau had 11 genomovars. The strains of Marmot himalayan plague foci were given priority to genomovar 5 and 8, amounted to 611 strains, genomovar 8 accounted for 56.00% (471/841), genomovar 5 accounted for 23.07% (194/841). Besides, 3 new genomovars, including new 1(62 strains), new 2(52 strains), new 3(48 strains) were newly founded, and 12 strains of Microtus fuscus plague foci were genomovar 14. The main host and media of Qinghai plateau plague foci directly affected the spatial

Unraveling of permafrost hydrological variabilities on Central Qinghai-Tibet Plateau using stable isotopic technique.

PubMed

Yang, Yuzhong; Wu, Qingbai; Hou, Yandong; Zhang, Zhongqiong; Zhan, Jing; Gao, Siru; Jin, Huijun

2017-12-15

Permafrost degradation on the Qinghai-Tibet Plateau (QTP) will substantially alter the surface runoff discharge and generation, which changes the recharge processes and influences the hydrological cycle on the QTP. Hydrological connections between different water bodies and the influence of thawing permafrost (ground ice) are not well understood on the QTP. This study applied water stable isotopic method to investigate the permafrost hydrological variabilities in Beiluhe Basin (BLB) on Central QTP. Isotopic variations of precipitation, river flow, thermokarst lake, and near-surface ground ice were identified to figure out the moisture source of them, and to elaborate the hydrological connections in permafrost region. Results suggested that isotopic seasonalities in precipitation is evident, it is showing more positive values in summer seasons, and negative values in winter seasons. Stable isotopes of river flow are mainly distributed in the range of precipitation which is indicative of important replenishment from precipitation. δ 18 O, δD of thermokarst lakes are more positive than precipitation, indicating of basin-scale evaporation of lake water. Comparison of δ I values in different water bodies shows that hydrology of thermokarst lakes was related to thawing of permafrost (ground ice) and precipitation. Near-surface ground ice in BLB exhibits different isotopic characteristics, and generates a special δD-δ 18 O relationship (freezing line): δD=5.81δ 18 O-23.02, which reflects typical freezing of liquid water. From isotopic analysis, it is inferred that near-surface ground ice was mainly recharged by precipitation and active layer water. Stable isotopic and conceptual model is suggestive of striking hydrological connections between precipitation, river flow, thermokarst lake, and ground ice under degrading permafrost. This research provides fundamental comprehensions into the hydrological processes in permafrost regions on QTP, which should be considered

Trace element accumulation in bivalve mussels Anodonta woodiana from Taihu Lake, China.

PubMed

Liu, Hongbo; Yang, Jian; Gan, Juli

2010-11-01

Data are presented for 13 trace metals (Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, and Pb) in 38 bivalve mussels Anodonta woodiana from four separate sites (Huzhou, Dapu, Sansandao, and Manshan) around the Taihu Lake of China. All elemental concentrations generally ranked in decreasing order, Mn > Fe > Zn > As ≈ Cu ≈ Cd ≈ Se > Pb > Mo ≈ Ag, except that Cr, Co, and Ni were not detected. Anodonta woodiana was able to bioaccumulate essential Mn and toxic Cd to the extremely high level of 19,240 and 53 mg/kg dry weight, respectively. Geographical differences in the concentrations of trace elements were usually significant between sampling sites except for As and Pb, and the mussels from Sanshandao site had mostly accumulated or were contaminated with essential and toxic elements. The residue level of Cd in A. woodiana from the Sanshandao and Manshan sites appeared to be even higher than those of the essential elements Cu and Se, and exceeded the corresponding maximum residue limits of China. The present study provides the most recent information on trace element bioaccumulation or contamination in Taihu Lake and, further, suggests that A. woodiana can be used as a suitable bioindicator for inland water environmental monitoring.

Long term (1997-2014) spatial and temporal variations in nitrogen in Dongting Lake, China

PubMed Central

Tian, Zebin; Zheng, Binghui; Wang, Lijing; Li, Liqiang; Wang, Xing; Li, Hong; Norra, Stefan

2017-01-01

In order to protect the water quality of Dongting Lake, it is significant to find out its nitrogen pollution characteristics. Using long-term monthly to seasonally data (1997–2014), we investigated the spatial and temporal variations in nitrogen in Dongting Lake, the second largest freshwater lake in China. The average concentrations of total nitrogen (TN) in the eastern, southern, and western parts of the lake were 1.77, 1.56, and 1.35 mg/L, respectively, in 2014. TN pollution was generally worse in the southern area than in the western area. Concentrations showed temporal variation, and were significantly higher during the dry season than during the wet season. Based on the concentration and growth rate of TN, three different stages were identified in the long term lake data, from 1997 to 2002, from 2003 to 2008, and from 2009 to 2014, during which the concentrations and the growth rate ranged from 1.09–1.51 mg/L and 22.09%-40.03%, 1.05–1.57 mg/L and -9.05%-7.74%, and 1.68–2.02 mg/L and 57.99%-60.41%, respectively. The main controls on the lake water TN concentrations were the quality and quantity of the lake inflows, spatial and temporal variations in hydrodynamic conditions within the lake (flow velocity, flow direction), and point and nonpoint inputs from human activities. Diffuse nutrient losses from agricultural land are a significant contributor. As a priority, the local government should aim to control the pollutant inputs from upstream and non-point nutrient losses from land. PMID:28166245

Catchment nitrogen saturation drives ecological change in an alpine lake in SW China (eastern margin of Tibet)

NASA Astrophysics Data System (ADS)

Anderson, N. J.; Hu, Z.; Yang, X.; Zhang, E.

2011-12-01

There is substantial evidence for recent (last ca. 120 years) ecological change in remote arctic and alpine lakes (increased productivity, altered biological structure). Initially, these changes were attributed to global warming which has altered the heat budgets of these lakes (stronger stratification, longer ice free periods). The emphasis on temperature, however, ignores that global environmental change is driven by a range of multiple stressors (e.g. altered biogeochemical cycles, land cover change). One of the characteristics of the observed change in remote lakes is the expansion of small species of the planktonic diatom genus Cyclotella. It is increasingly obvious that the recent success of this diatom genus is driven by other factors (nutrients, light, mixing depth) as much as temperature. SE Asia is a major hotspot for the emission of reactive nitrogen as a result of intensive agriculture and fossil fuel combustion. In this study we report recent ecological change in a small, oligotrophic alpine lake (ShadeCo; altitude 4423 m) located in Sichuan Province (SW China), one of many relatively unstudied alpine lakes on the eastern margin of Tibet. The lake is located above the tree-line and there is no cultural land-use; the catchment vegetation is dominated by alpine shrub (predominantly Rhododendron). We used a multi-proxy palaeolimnological approach (diatom, geochemical and stable isotope analyses of a 210-Pb dated core) coupled with regional long-term climate data to understand the pronounced 20th century changes in the diatom record, notably an expansion of Cyclotella spp from around 1920. This initial increase is coincident with warming in SW China but the maximum Cyclotella abundance occurs in in the 1970s and 1980s, a period of regional cooling and major changes in catchment-lake biogeochemistry as indicated by geochemical analyses. The possible drivers of the observed changes (nitrogen deposition, temperature) at this site are discussed in the context

The Hughes phenomenon in hyperspectral classification based on the ground spectrum of grasslands in the region around Qinghai Lake

NASA Astrophysics Data System (ADS)

Ma, Weiwei; Gong, Cailan; Hu, Yong; Meng, Peng; Xu, Feifei

2013-08-01

Hyperspectral data, consisting of hundreds of spectral bands with a high spectral resolution, enables acquisition of continuous spectral characteristic curves, and therefore have served as a powerful tool for vegetation classification. The difficulty of using hyperspectral data is that they are usually redundant, strongly correlated and subject to Hughes phenomenon where classification accuracy increases gradually in the beginning as the number of spectral bands or dimensions increases, but decreases dramatically when the band number reaches some value. In recent years，some algorithms have been proposed to overcome the Hughes phenomenon in classification, such as selecting several bands from full bands, PCA- and MNF-based feature transformations. Up to date, however, few studies have been conducted to investigate the turning point of Hughes phenomenon (i.e., the point at which the classification accuracy begins to decline). In this paper, we firstly analyze reasons for occurrence of Hughes phenomenon, and then based on the Mahalanobis classifier, classify the ground spectrum of several grasslands which were recorded in September 2012 using FieldSpec3 spectrometer in the regions around Qinghai Lake，a important pasturing area in the north of China. Before classification, we extract features from hyperspectral data by bands selecting and PCA- based feature transformations, and In the process of classification, we analyze how the correlation coefficient between wavebands, the number of waveband channels and the number of principal components affect the classification result. The results show that Hushes phenomenon may occur when the correlation coefficient between wavebands is greater than 94%，the number of wavebands is greater than 6, or the number of principal components is greater than 6. Best classification result can be achieved (overall accuracy of grasslands 90%) if the number of wavebands equals to 3 (the band positions are 370nm, 509nm and 886nm

Substrate degradation and nutrient enrichment structuring macroinvertebrate assemblages in agriculturally dominated Lake Chaohu Basins, China.

PubMed

Zhang, You; Cheng, Long; Tolonen, Katri E; Yin, Hongbin; Gao, Junfeng; Zhang, Zhiming; Li, Kuanyi; Cai, Yongjiu

2018-06-15

Rapid agricultural development has induced severe environmental problems to freshwater ecosystems. In this study, we aimed to examine the structure and environmental determinants of macroinvertebrate assemblages in an agriculture dominated Lake Chaohu Basin, China. A cluster analysis of the macroinvertebrate communities identified four groups of sites that were characterized by significantly different macroinvertebrate species. These four groups of sites had concentric spatial distribution patterns that followed the variation in the environmental conditions from the less anthropogenically disturbed headwaters towards the more anthropogenically disturbed lower reaches of the rivers and the Lake Chaohu. Moreover, taxa richness decreased from the headwaters towards the Lake Chaohu. The increasing practice of agriculture has reduced the abundances and richness of pollution sensitive species while opposite effects on pollution tolerant species. The study identified substrate heterogeneity and nutrient concentrations as the key environmental factors regulating the changes in the macroinvertebrate communities. We propose that particular attentions should be paid to reduce the nutrient enrichment and habitat degradation in the Lake Chaohu Basin and similar agriculture dominated basins. Copyright © 2018 Elsevier B.V. All rights reserved.

Precipitation and temperature drive seasonal variation in bioaccumulation of polycyclic aromatic hydrocarbons in the planktonic food webs of a subtropical shallow eutrophic lake in China.

PubMed

Tao, Yuqiang; Yu, Jing; Xue, Bin; Yao, Shuchun; Wang, Sumin

2017-04-01

Hydrophobic organic contaminants (HOCs) are toxic and ubiquitous in aquatic environments and pose great risks to aquatic organisms. Bioaccumulation by plankton is the first step for HOCs to enter aquatic food webs. Trophic status is considered to dominate variations in bioaccumulation of HOCs in plankton in temperate and frigid deep oligotrophic waters. However, long-term driving factors for bioaccumulation of HOCs in planktonic food webs of subtropical shallow eutrophic waters have not been well investigated. China has the largest subtropical lake density in the Northern Hemisphere. Due to limited field data, long-term variations in the bioaccumulation of HOCs in these lakes are almost unknown. Here we take Lake Xuanwu as an example to investigate long-term variations in the bioaccumulation, and biomagnification of polycyclic aromatic hydrocarbon (PAHs) in planktonic food webs of subtropical shallow eutrophic lakes in China, and elucidate the driving factors. Our results indicate that temperature rather than nutrients dominates long-term dynamics of planktonic biomass in this lake. Precipitation significantly enhances the concentrations of the PAHs, and total suspended particles, and consequently affects the distribution of the PAHs in the water column. Biomass dilution induced by temperature dominates bioaccumulation of the PAHs by both phytoplankton and zooplankton (copepods and cladocerans). Biomagnification of the PAHs from phytoplankton to zooplankton is positively correlated with temperature. Our study suggests that temperature and precipitation drive long-term variations in the bioaccumulation of the PAHs in the planktonic food webs of this subtropical shallow eutrophic lake. Lake Xuanwu has a similar mean annual temperature, annual precipitation, sunshine duration, and nutrient levels as other subtropical shallow eutrophic lakes in China. This study may also help to understand the bioaccumulation of HOCs in planktonic food webs of other subtropical shallow

Climatic warming and overgrazing induced the high concentration of organic matter in Lake Hulun, a large shallow eutrophic steppe lake in northern China.

PubMed

Chen, Xiaofeng; Chuai, Xiaoming; Yang, Liuyan; Zhao, Huiying

2012-08-01

An abnormally high concentration of organic matter (OM) in Lake Hulun, a large shallow eutrophic lake located in the sparsely populated Hulun Buir Steppe, was observed in a field investigation. Little was known about the origin of the OM. To identify the source of the OM in Lake Hulun, the carbon/nitrogen (C/N) ratio, natural abundance of stable isotope and three dimensional excitation emission matrix (3DEEM) fluorescence spectroscopy techniques were employed. Furthermore, a cyanobacterial incubation and degradation experiment was conducted in the laboratory to quantify the contribution of algae to dissolved organic matter (DOM) in Lake Hulun. C/N, the stable carbon isotope (δ(13)C) values typical of C3 plant debris in particulate organic matter (POM) and the fluorescence indices of DOM indicate that most of the OM in Lake Hulun is of terrigenous origin. It was deduced that only about 10.2% and 7.3% of DOM were contributed by algae in September and January, respectively, according to the linear correlation between the concentrations of algae-derived DOM and the fluorescence intensities of tyrosine-like matter. According to the stockbreeding development and climate change in Hunlun Buir Steppe, we deduced that the destruction of the grassland ecosystem by overgrazing in specific locations and trends in climatic warming and drying were the main factors causing the increase of OM and nutrient concentrations in Lake Hulun. This result highlights the need to pay more attention to the inputs of terrigenous organic matter to the lakes in northern China. Copyright © 2012 Elsevier B.V. All rights reserved.

[Investigation on malaria knowledge and demands on related training for CDC staff in Qinghai Province, China].

PubMed

Shao-Sen, Zhang; Hui-Xia, Cai; Hong, Tu; He, Yan; Na, Liu; Jun-Ying, Ma

2017-04-07

To investigate the malaria knowledge of CDC staff and their demands on related training in malaria non-endemic areas, so as to provide the reference for planning the appropriate curriculum. All the participants who were the staff of county CDCs all over Qinghai Province and attended the provincial training workshop were surveyed. A self-administered questionnaire survey was carried out and the data was statistically analyzed. A total of 115 participants were involved in this survey. They were mostly (85.21%) from county CDCs. The general knowledge of malaria among the respondents was well, and the average rate of correct answers was 70.35%. However, the answers to the general knowledge of malaria and anti-malaria treatment were not well enough. The rates of correct answers were 61.96% and 48.99% respectively. The differences among the groups of job title ranking, department of working and level of CDC were not significant ( F = 0.13-2.02, all P > 0.05). The number of correct answers was significantly increased after the training course. The average score after the training was 79.20±15.16 while the pre-training score was 70.34±17.46 ( t = 3.86, P < 0.05), especially in the answers to general malaria knowledge and malaria surveillance and response ( t = 4.30, 4.97, both P < 0.05). The general knowledge of malaria was considered as the most need of training as 80% of the respondents voted "Yes", according to the demand analysis. There was no significant difference among the different groups ( F = 0.61-3.11, both P > 0.05). The malaria knowledge is well mastered by the staff of CDCs in Qinghai Province, and the further training courses are requested and addressed in the target areas such as general malaria knowledge, anti-malaria treatment, malaria surveillance and response.

Genetic diversity and distribution patterns of host insects of Caterpillar Fungus Ophiocordyceps sinensis in the Qinghai-Tibet Plateau.

PubMed

Quan, Qing-Mei; Chen, Ling-Ling; Wang, Xi; Li, Shan; Yang, Xiao-Ling; Zhu, Yun-Guo; Wang, Mu; Cheng, Zhou

2014-01-01

The caterpillar fungus Ophiocordyceps sinensis is one of the most valuable medicinal fungi in the world, and it requires host insects in family Hepialidae (Lepidoptera) to complete its life cycle. However, the genetic diversity and phylogeographic structures of the host insects remain to be explored. We analyzed the genetic diversity and temporal and spatial distribution patterns of genetic variation of the host insects throughout the O. sinensis distribution. Abundant haplotype and nucleotide diversity mainly existed in the areas of Nyingchi, ShangriLa, and around the edge of the Qinghai-Tibet Plateau, where are considered as the diversity center or micro-refuges of the host insects of O. sinensis. However, there was little genetic variation among host insects from 72.1% of all populations, indicating that the host species composition might be relatively simple in large-scale O. sinensis populations. All host insects are monophyletic except for those from four O. sinensis populations around Qinghai Lake. Significant phylogeographic structure (NST>GST, P<0.05) was revealed for the monophyletic host insects, and the three major phylogenetic groups corresponded with specific geographical areas. The divergence of most host insects was estimated to have occurred at ca. 3.7 Ma, shortly before the rapid uplift of the QTP. The geographical distribution and star-like network of the haplotypes implied that most host insects were derived from the relicts of a once-widespread host that subsequently became fragmented. Neutrality tests, mismatch distribution analysis, and expansion time estimation confirmed that most host insects presented recent demographic expansions that began ca. 0.118 Ma in the late Pleistocene. Therefore, the genetic diversity and distribution of the present-day insects should be attributed to effects of the Qinghai-Tibet Plateau uplift and glacial advance/retreat cycles during the Quaternary ice age. These results provide valuable information to guide

Trace elements in fish from Taihu Lake, China: levels, associated risks, and trophic transfer.

PubMed

Hao, Ying; Chen, Liang; Zhang, Xiaolan; Zhang, Dongping; Zhang, Xinyu; Yu, Yingxin; Fu, Jiamo

2013-04-01

Concentrations of eight trace elements [iron (Fe), manganese (Mn), zinc (Zn), chromium (Cr), mercury (Hg), cadmium (Cd), lead (Pb), and arsenic (As)] were measured in a total of 198 samples covering 24 fish species collected from Taihu Lake, China, in September 2009. The trace elements were detected in all samples, and the total mean concentrations ranged from 18.2 to 215.8 μg/g dw (dry weight). The concentrations of the trace elements followed the sequence of Zn>Fe>Mn>Cr>As>Hg>Pb>Cd. The measured trace element concentrations in fish from Taihu Lake were similar to or lower than the reported values in fish around the world. The metal pollution index was used to compare the total trace element accumulation levels among various species. Toxabramis swinhonis (1.606) accumulated the highest level of the total trace elements, and Saurogobio dabryi (0.315) contained the lowest. The concentrations of human non-essential trace elements (Hg, Cd, Pb, and As) were lower than the allowable maximum levels in fish in China and the European Union. The relationships between the trace element concentrations and the δ(15)N values of fish species were used to investigate the trophic transfer potential of the trace elements. Of the trace elements, Hg might be biomagnified through the food chain in Taihu Lake if the significant level of p-value was set at 0.1. No biomagnification and biodilution were observed for other trace elements. Copyright © 2012 Elsevier Inc. All rights reserved.

Water Bacterial and Fungal Community Compositions Associated with Urban Lakes, Xi’an, China

PubMed Central

Zhang, Haihan; Wang, Yue; Chen, Shengnan; Zhao, Zhenfang; Feng, Ji; Zhang, Zhonghui; Lu, Kuanyu; Jia, Jingyu

2018-01-01

Urban lakes play a vital role in the sustainable development of urbanized areas. In this freshwater ecosystem, massive microbial communities can drive the recycling of nutrients and regulate the water quality. However, water bacterial and fungal communities in the urban lakes are not well understood. In the present work, scanning electron microscopy (SEM) was combined with community level physiological profiles (CLPPs) and Illumina Miseq sequence techniques to determine the diversity and composition of the water bacterial and fungal community in three urban lakes, namely Xingqing lake (LX), Geming lake (LG) and Lianhu lake (LL), located in Xi’an City (Shaanxi Province, China). The results showed that these three lakes were eutrophic water bodies. The highest total nitrogen (TN) was observed in LL, with a value of 12.1 mg/L, which is 2 times higher than that of LG. The permanganate index (CODMn) concentrations were 21.6 mg/L, 35.4 mg/L and 28.8 mg/L in LG, LL and LX, respectively (p < 0.01). Based on the CLPPs test, the results demonstrated that water bacterial communities in the LL and LX urban lakes had higher carbon source utilization ability. A total of 62,742 and 55,346 high quality reads were grouped into 894 and 305 operational taxonomic units (OTUs) for bacterial and fungal communities, respectively. Water bacterial and fungal community was distributed across 14 and 6 phyla. The most common phyla were Proteobacteriaand Cyanobacteria. Cryptomycota was particularly dominant in LL, while Chytridiomycota and Entomophthormycota were the most abundant fungal phyla, accounting for 95% of the population in the LL and 56% in the LG. Heat map and redundancy analysis (RDA) highlighted the dramatic differences of water bacterial communities among three urban lakes. Meanwhile, the profiles of fungal communities were significantly correlated with the water quality parameters (e.g., CODMn and total nitrogen, TN). Several microbes (Legionella sp. and Streptococcus sp

Water Bacterial and Fungal Community Compositions Associated with Urban Lakes, Xi'an, China.

PubMed

Zhang, Haihan; Wang, Yue; Chen, Shengnan; Zhao, Zhenfang; Feng, Ji; Zhang, Zhonghui; Lu, Kuanyu; Jia, Jingyu

2018-03-07

Urban lakes play a vital role in the sustainable development of urbanized areas. In this freshwater ecosystem, massive microbial communities can drive the recycling of nutrients and regulate the water quality. However, water bacterial and fungal communities in the urban lakes are not well understood. In the present work, scanning electron microscopy (SEM) was combined with community level physiological profiles (CLPPs) and Illumina Miseq sequence techniques to determine the diversity and composition of the water bacterial and fungal community in three urban lakes, namely Xingqing lake (LX), Geming lake (LG) and Lianhu lake (LL), located in Xi'an City (Shaanxi Province, China). The results showed that these three lakes were eutrophic water bodies. The highest total nitrogen (TN) was observed in LL, with a value of 12.1 mg/L, which is 2 times higher than that of LG. The permanganate index (COD Mn ) concentrations were 21.6 mg/L, 35.4 mg/L and 28.8 mg/L in LG, LL and LX, respectively ( p < 0.01). Based on the CLPPs test, the results demonstrated that water bacterial communities in the LL and LX urban lakes had higher carbon source utilization ability. A total of 62,742 and 55,346 high quality reads were grouped into 894 and 305 operational taxonomic units (OTUs) for bacterial and fungal communities, respectively. Water bacterial and fungal community was distributed across 14 and 6 phyla. The most common phyla were Proteobacteriaand Cyanobacteria. Cryptomycota was particularly dominant in LL, while Chytridiomycota and Entomophthormycota were the most abundant fungal phyla, accounting for 95% of the population in the LL and 56% in the LG. Heat map and redundancy analysis (RDA) highlighted the dramatic differences of water bacterial communities among three urban lakes. Meanwhile, the profiles of fungal communities were significantly correlated with the water quality parameters (e.g., COD Mn and total nitrogen, TN). Several microbes ( Legionella sp. and Streptococcus sp

Simultaneous determination of molecular weights and contents of water-soluble polysaccharides and their fractions from Lycium barbarum collected in China.

PubMed

Wu, Ding-Tao; Lam, Shing-Chung; Cheong, Kit-Leong; Wei, Feng; Lin, Peng-Cheng; Long, Ze-Rong; Lv, Xiao-Jie; Zhao, Jing; Ma, Shuang-Cheng; Li, Shao-Ping

2016-09-10

Molecular weights and contents of water-soluble polysaccharides and their fractions in fifty batches of fruits of Lycium barbarum (wolfberry) collected from different regions of China, including Qinghai, Ningxia, Inner Mongolia, Xinjiang, and Gansu, were simultaneously determined using high performance size exclusion chromatography (HPSEC) coupled with multi angle laser light scattering (MALLS) and refractive index detector (RID) with the refractive index increment (dn/dc). Results showed that HPSEC chromatograms and molecular weight distributions of polysaccharides in L. barbarum collected from different regions of China were similar. Furthermore, the average contents of each polysaccharide fraction (peaks 1, 2, and 3) in crude polysaccharides of L. barbarum collected from Ningxia were similar with those of Inner Mongolia, Xinjiang, and Gansu, respectively. However, significant difference was found between polysaccharides in L. barbarum collected from Ningxia and Qinghai. Moreover, the average amounts of total polysaccharide fractions (peaks 1, 2, and 3) in the raw material of L. barbarum collected from Ningxia were significantly higher than that of Qinghai. These results may contribute to the rational usage of L. barbarum produced in China, and are beneficial for the improvement of their quality control. Results suggested that HPSEC-MALLS-RID with the dn/dc method could be used as a routine method for the quality evaluation of polysaccharides from natural resources and their products. Copyright © 2016 Elsevier B.V. All rights reserved.

Heavy-metal pollution and potential ecological risk assessment of sediments from Baihua Lake, Guizhou, P.R. China.

PubMed

Huang, Xianfei; Hu, Jiwei; Li, Cunxiong; Deng, Jiajun; Long, Jian; Qin, Fanxin

2009-12-01

Baihua Lake, a man-made reservoir, is one of the five drinking water sources for Guiyang City in China's southwestern province of Guizhou. In the present research, the distribution and accumulation characteristics of heavy metals (Pb, Cd, As, Cu and Zn) for the sediment of this lake were analyzed by examination of 10 recently collected samples. A method based on toxic-response factor was applied to assess the potential ecological risk of these heavy metals to the water body. For comparison, the two sets of reference data representing the pre-industrial and the local baseline pollution levels were employed to derive the accumulating coefficients for the heavy metals under study. The calculated potential ecological risk indices show that the lake was polluted by heavy metals and both cadmium and arsenic loadings were critical factors responsible for the ecological hazards posed to Baihua Lake by the five elements.

Modified Convair-240 aircraft at Naval Weapons Center, China Lake, California

NASA Technical Reports Server (NTRS)

1987-01-01

Convair-240 aircraft modified to fill role of a Space Shuttle is parked outside aircraft hangar at Naval Weapons Center, China Lake, California. Space shuttle side hatch mockup is incorporated in fuselage (visible toward the aft section of the aircraft). Convair-240 aircraft is part of November crew escape system (CES) testing of a candidate concept developed to provide crew egress capability during Space Shuttle controlled gliding flight. Tractor rocket testing using the Convair-240 will begin 11-20-87. Life-like dummies will be pulled by the rockets from the modified aircraft's side hatch mockup.

Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China.

PubMed

Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

2016-03-07

Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively.

The occurrence and distribution of antibiotics in Lake Chaohu, China: seasonal variation, potential source and risk assessment.

PubMed

Tang, Jun; Shi, Taozhong; Wu, Xiangwei; Cao, Haiqun; Li, Xuede; Hua, Rimao; Tang, Feng; Yue, Yongde

2015-03-01

The distribution and seasonal variation of fifteen antibiotics belonging to three classes (sulfonamides, fluoroquinolones and tetracyclines) were investigated in Lake Chaohu, China. The concentrations of the selected antibiotics in the surface water, eight major inflowing rivers and sewage treatment plant (STP) samples were analyzed by UPLC-MS/MS. The results indicated that sulfamethoxazole and ofloxacin were the predominant antibiotics, with maximum concentrations of 95.6 and 383.4ngL(-1), respectively, in the river samples. In Lake Chaohu, the western inflowing rivers (the Nanfei and Shiwuli Rivers) were the primary import routes for the antibiotics, and the domestic effluent from four STPs were considered the primary source of the antibiotics. The level of antibiotics in Lake Chaohu clearly varied with seasonal changes, and the highest detectable frequencies and mean concentrations were found during the winter. The quality of water downstream of Lake Chaohu was influenced by the lake, and the results of risk assessment of the antibiotics on aquatic organisms suggested that sulfamethoxazole, ofloxacin, ciprofloxacin and enrofloxacin in the surface water of Lake Chaohu and inflowing rivers might pose a high risk to algae and plants. Copyright © 2014 Elsevier Ltd. All rights reserved.

Role of rainwater induced subsurface flow in water-level dynamics and thermoerosion of shallow thermokarst ponds on the Northeastern Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Pan, X.; Yu, Q.; You, Y.

2014-12-01

Understanding hydrological and thermal regimes of thermokarst lakes is of great importance for predicting their responses to climate change. However, mechanism of water-level dynamics and associated thermal effects on thermoerosion of thermokarst lakes are still not well understood on the Qinghai-Tibet Plateau (QTP). In this study, we investigate two typical shallow thermokarst ponds (namely small lakes) in a warm permafrost region with thick active layer on the northeastern QTP through quantifying water budget. Results demonstrate that, rainfall induced subsurface lateral flow dominates pond water-level regime. Annual variation of pond water-level relies on areal water budget of surrounding active layer, particularly the high variable of precipitation. Besides, it is worth noting the extraordinary warming during the late ice-cover period, because marked air gap between upper ice-cover and underlying water, led by the upward thawing of thick ice-cover, might result in greenhouse-like condition due to the unique weather that strong solar radiation and little snowpack. This hydrological mechanism also exerts evident impacts on thermal regime and thermoerosion of the shallow thermokarst ponds, and they are closely related to retreat of thermokarst pondshore and underlying permafrost degradation. These findings imply a localized model addressing the unique hydrological and thermal regimes of thermokarst lakes would be essential to study the evolution of these shallow rainwater dominated thermokarst ponds on the QTP.

Golden Key Program. Common Education for Visually Impaired Children in Western China.

ERIC Educational Resources Information Center

Xu, Bailun

This paper describes a new program in the Western provinces of China (Guangxi, Guizhou, Yunnan, Gansu, Ningxia, Qinghai, Xinjiang, Tibet, and Inner Mongolia) that is designed to integrate 20,000 children with low-vision into general education classrooms. The Golden Key Research Center of Education for Visually Impaired has been working with the…

Halogenated organic contaminants (HOCs) in sediment from a highly eutrophicated lake, China: occurrence, distribution and mass inventories.

PubMed

Wang, Ji-Zhong; Liu, Liang-Ying; Zhang, Kai; Liang, Bo; Li, Guo-Lian; Chen, Tian-Hu

2012-11-01

Halogenated organic contaminants (HOCs) including 16 polybrominated diphenyl ethers (PBDEs) and 37 polychlorinated biphenyls (PCBs) were determined in 49 surfacial sediments from Chaohu Lake, a highly eutrophicated lake, China. PBDEs were detected in almost samples with the range of the total concentration (defined as Σ(16)PBDEs) from 0.84 to 86.6 ng g(-1). Compared with the occurrence of PBDEs in Pearl River Delta and Yangtze River Delta in China, lower percentage of BDE-209 over the concentration of Σ(16)PBDEs was inferred by the high-volume application of penta-BDE mixture product for local domestic furniture purpose. The total concentration of 37 PCBs (Σ(37)PCBs) ranged from 0.05 to 3.36 ng g(-1) with the most detection of PCB-1, -4, -52 and -71. Both the concentrations of Σ(16)PBDE and Σ(37)PCB poorly correlated with total organic carbon (TOC), suggesting the significant contribution of phytoplankton organic carbons to sediment TOC. The contamination by PBDEs and PCBs in western region of the lake was significantly more serious than in eastern lake. Our findings about the higher residues of PBDEs and PCBs in sediments at the estuary of Nanfei River compared to the other estuaries also supported the conclusion that urban area (Hefei city) was the main source of PBDEs and PCBs. The comparison with the concentration of HOC in the present study with those in other lacustrine sediments around the world suggested the contamination by PBDEs in Chaohu Lake is at middle of the global concentration range, whereas PCBs is at low end of the global range which could be elucidated by local economic development and historical usage of PBDEs and PCBs. The mass inventories of HOCs in the lake were estimated at 561 and 38 kg, which corresponds to only 0.000006% and 0.0001% of these global historical produce volumes, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Girls First! Promoting Early Education in Tibetan Areas of China, a Case Study

ERIC Educational Resources Information Center

Seeberg, Vilma

2008-01-01

This study explores conditions promoting girls' education in ethnic Tibetan pastoral highlands of the Qinghai-Tibet plateau of western China. Global discourse and cross national evidence on the transgenerational benefits of girls' education has shown prioritizing girls' education to be the most effective strategy of breaking the vicious cycle of…

Characteristics and causal factors of hysteresis in the hydrodynamics of a large floodplain system: Poyang Lake (China)

NASA Astrophysics Data System (ADS)

Zhang, X. L.; Zhang, Q.; Werner, A. D.; Tan, Z. Q.

2017-10-01

A previous modeling study of the lake-floodplain system of Poyang Lake (China) revealed complex hysteretic relationships between stage, storage volume and surface area. However, only hypothetical causal factors were presented, and the reasons for the occurrence of both clockwise and counterclockwise hysteretic functions were unclear. The current study aims to address this by exploring further Poyang Lake's hysteretic behavior, including consideration of stage-flow relationships. Remotely sensed imagery is used to validate the water surface areas produced by hydrodynamic modeling. Stage-area relationships obtained using the two methods are in strong agreement. The new results reveal a three-phase hydrological regime in stage-flow relationships, which assists in developing improved physical interpretation of hysteretic stage-area relationships for the lake-floodplain system. For stage-area relationships, clockwise hysteresis is the result of classic floodplain hysteretic processes (e.g., restricted drainage of the floodplain during recession), whereas counterclockwise hysteresis derives from the river hysteresis effect (i.e., caused by backwater effects). The river hysteresis effect is enhanced by the time lag between the peaks of catchment inflow and Yangtze discharge (i.e., the so-called Yangtze River blocking effect). The time lag also leads to clockwise hysteresis in the relationship between Yangtze River discharge and lake stage. Thus, factors leading to hysteresis in other rivers, lakes and floodplains act in combination within Poyang Lake to create spatial variability in hydrological hysteresis. These effects dominate at different times, in different parts of the lake, and during different phases of the lake's water level fluctuations, creating the unique hysteretic hydrological behavior of Poyang Lake.

Incorporation of Complex Hydrological and Socio-economic Factors for Non-point Source Pollution Control: A Case Study at the Yincungang Canal, the Lake Tai Basin of China

NASA Astrophysics Data System (ADS)

Yang, X.; Luo, X.; Zheng, Z.

2012-04-01

It is increasingly realized that non-point pollution sources contribute significantly to water environment deterioration in China. Compared to developed countries, non-point source pollution in China has the unique characteristics of strong intensity and composition complexity due to its special socioeconomic conditions. First, more than 50% of its 1.3 billion people are rural. Sewage from the majority of the rural households is discharged either without or only with minimal treatment. The large amount of erratic rural sewage discharge is a significant source of water pollution. Second, China is plagued with serious agricultural pollution due to widespread improper application of fertilizers and pesticides. Finally, there lack sufficient disposal and recycling of rural wastes such as livestock manure and crop straws. Pollutant loads from various sources have far exceeded environmental assimilation capacity in many parts of China. The Lake Tai basin is one typical example. Lake Tai is the third largest freshwater lake in China. The basin is located in the highly developed and densely populated Yangtze River Delta. While accounting for 0.4% of its land area and 2.9% of its population, the Lake Tai basin generates more than 14% of China's Gross Domestic Production (GDP), and the basin's GDP per capita is 3.5 times as much as the state average. Lake Tai is vital to the basin's socio-economic development, providing multiple services including water supply for municipal, industrial, and agricultural needs, navigation, flood control, fishery, and tourism. Unfortunately, accompanied with the fast economic development is serious water environment deterioration in the Lake Tai basin. The lake is becoming increasingly eutrophied and has frequently suffered from cyanobacterial blooms in recent decades. Chinese government has made tremendous investment in order to mitigate water pollution conditions in the basin. Nevertheless, the trend of deteriorating water quality has yet to

Public Perception of Blue-Algae Bloom Risk in Hongze Lake of China

NASA Astrophysics Data System (ADS)

Huang, Lei; Sun, Kai; Ban, Jie; Bi, Jun

2010-05-01

In this work we characterize the public perception of one kind of ecological risk—blue-algae bloom in Hongze Lake, China, based on the psychometric paradigm method. In the first survey of May 2008, 300 respondents of Sihong County adjacent to Hongze Lake were investigated, with a total of 156 questionnaires returned. Then in a second survey of July 2008, 500 respondents from the same research area were investigated, with 318 questionnaires collected. This research firstly attempted to explore the local respondents’ degree of concern regarding ecological changes to Hongze Lake in the last ten years. Secondly, to explore the public perception of blue-algae bloom compared to three typical kinds of hazards including earthquake, nuclear power and public traffic. T-test was used to examine the difference of risk perception in these four hazards over time. The third part of this research, with demographic analysis and nonparametric statistical test, predicted the different groups of respondents’ willingness to accept (WTA) risk of blue-algae bloom in two surveys. Using multiple linear regression analysis, the risk perception model explained 28.3% of variance in the WTA blue-algae bloom risk. The variables of Knowledge, Social effect, Benefit, Controllability and Trust in government were significantly correlated with WTA, which implied that these variables were the main influencing factors explaining the respondents’ willingness to accept risk. The results would help the Chinese government to comprehend the public’s risk perception of the lake ecosystem, inducing well designed communication of risks with public and making effective mitigation policies to improve people’s rational risk judgment.

Public perception of blue-algae bloom risk in Hongze Lake of China.

PubMed

Huang, Lei; Sun, Kai; Ban, Jie; Bi, Jun

2010-05-01

In this work we characterize the public perception of one kind of ecological risk-blue-algae bloom in Hongze Lake, China, based on the psychometric paradigm method. In the first survey of May 2008, 300 respondents of Sihong County adjacent to Hongze Lake were investigated, with a total of 156 questionnaires returned. Then in a second survey of July 2008, 500 respondents from the same research area were investigated, with 318 questionnaires collected. This research firstly attempted to explore the local respondents' degree of concern regarding ecological changes to Hongze Lake in the last ten years. Secondly, to explore the public perception of blue-algae bloom compared to three typical kinds of hazards including earthquake, nuclear power and public traffic. T-test was used to examine the difference of risk perception in these four hazards over time. The third part of this research, with demographic analysis and nonparametric statistical test, predicted the different groups of respondents' willingness to accept (WTA) risk of blue-algae bloom in two surveys. Using multiple linear regression analysis, the risk perception model explained 28.3% of variance in the WTA blue-algae bloom risk. The variables of Knowledge, Social effect, Benefit, Controllability and Trust in government were significantly correlated with WTA, which implied that these variables were the main influencing factors explaining the respondents' willingness to accept risk. The results would help the Chinese government to comprehend the public's risk perception of the lake ecosystem, inducing well designed communication of risks with public and making effective mitigation policies to improve people's rational risk judgment.

Seasonal Variation of Arsenic Concentration in Natural Water of the Source Area of the Yellow River on the Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Yu, C.; Wen, L.; Yu, Z.

2017-12-01

Seasonal variation in the arsenic (As) concentration of natural water has been studied the first time in the source area of the Yellow River (SAYR) in Tibet, China. Samples were collected in the lake, river and spring across the whole area in April (spring) and July (summer), 2014. In April the average values of arsenic concentration in SAYR from high to low were: lake (38.1μg/L, n=47, range 8.6-131.0μg/L) > river (24.3μg/L, n=83, range 4.3-77.1μg/L) > spring (19.1μg/L, n=12, range 12.0-29.4μg/L). In July the same order of the average values of arsenic concentration in SAYR was found: lake (14.1μg/L, n=57, range 5.8-68.5μg/L) > river (7.3μg/L, n=106, range 3.6-22.9μg/L)> spring (6.7μg/L, n=9, range 4.8-8.2μg/L).The average arsenic concentrations in April were almost three times higher than those in July. In both season, the higher concentrations of arsenic were distributed in the upper reaches above the two biggest lakes of Gyaring and Ngoring Lakes in SAYR. The two big lakes buffered the naturally generated arsenic concentration in surface water, suggesting the important ecological role of the lakes. Generally, the lower concentrations in July probably were due to 1. the dilution effect of the precipitation; 2 the change of water sources. In April when the permafrost and mountain snow started to thaw and melt, ground water with high arsenic concentration was the main water source with high concentration of arsenic; but in July, with the increase of the temperature, mountain snow, permafrost would contribute more than in April, in addition, the main arsenic contributor groundwater was diluted by the precipitation recharge. Since in spring, lake and river water arsenic concentration decreased with almost the same magnitude., assuming the dilution effect dominant. The exported arsenic from SAYR in April (903.4Kg) were twice more than it in July (449.1Kg), because the flowrates were similar in the two months, the water source of the runoff components was

One-century sedimentary record of heavy metal pollution in western Taihu Lake, China.

PubMed

Li, Yan; Zhou, Shenglu; Zhu, Qing; Li, Baojie; Wang, Junxiao; Wang, Chunhui; Chen, Lian; Wu, Shaohua

2018-05-16

Long-term trends of sediment compositions are important for assessing the impact of human activities on the sediment and protecting the sediment environment. In this study, based on the contents of heavy metals and the Pb isotope ratios in lake sediments, atmospheric dustfall and soil in Yixing, China, the representative heavy metals (Zn, Pb, Cr and Cd) in lake sediments from western Taihu Lake were studied. The evolution history of heavy metals in the local environment was constructed for the past 100 years. From 1892 to the 1990s, the anthropogenic fluxes of the representative heavy metals were negligible, indicating minimal anthropogenic emissions of heavy metals. Since the 1990s, anthropogenic fluxes of the representative heavy metals began to increase, concurrent with the economic growth and development in the western Taihu Lake Basin after the Chinese economic reform. The maximum flux percentage of the heavy metals in the sediments, caused by human activities, is 23.0% for Zn, 31.6% for Pb, 39.5% for Cr and 85.3% for Cd, indicating that most of the Cd comes from human activities. The Cd content in the western Taihu Lake Basin was significantly higher than that in the other areas, and the rapid development of the industry in the western Taihu Lake Basin and ceramics in Yixing led to the enrichment of heavy metals in local sediments. Since the 21st century, measures have been taken to control the pollution of heavy metals, including the increase in local government attention and the deployment of environmental monitoring technology. However, heavy metal content remains high, and the Pb content is still increasing. The ratios of Pb isotopes show that the main sources of heavy metals in the western Taihu Lake sediments, the local soil of Yixing and the atmospheric dustfall are coal combustion, leaded gasoline combustion, industrial wastewater and domestic sewage. Copyright © 2018 Elsevier Ltd. All rights reserved.

Streptococcus halotolerans sp. nov. isolated from the respiratory tract of Marmota himalayana in Qinghai-Tibet Plateau of China.

PubMed

Niu, Lina; Lu, Shan; Hu, Shoukui; Jin, Dong; Lai, Xinhe; Yang, Jing; Chen, Cuixia; Wang, Yiting; Bai, Xiangning; Lan, Ruiting; Lv, Gang; Xie, Yingping; Ye, Changyun; Xu, Jianguo

2016-10-01

Two Gramstaining-positive, catalase-negative, α-hemolytic, coccus-shaped organisms were isolated separately from the respiratory tracts of two Marmota himalayana animals from the Qinghai-Tibet Plateau, PR China. Morphological, biological, biochemical, and molecular genetic studies were performed on these two isolates (HTS9T and HTS12). Their biochemical characteristics, such as acid production from different sugars and enzymatic activities, indicated that they represented a member of the genus Streptococcus. They are most closely related to Streptococcus thoraltensis CIP 105518T based on sequence analysis of their 16S rRNA, groEL, sodA and rpoB genes, with similarities of 97.6, 89.9, 92.6 and 91.1 % the four genes respectively. The whole genome phylogenetic tree reconstructed using 372 core genes from 65 genomes of members of the genus Streptococcus validates that HTS9T forms a distinct subline and exhibits specific phylogenetic affinity with S. thoraltensis. In silico DNA-DNA hybridization of HTS9T showed a DNA reassociation value of 32.1 %, closest to that of S. thoraltensis CIP 105518T. Based on their phenotypic characteristics and in particular the phylogenetic findings (DNA-DNA hybridization, three phylogenetic trees built from the partial 16S rRNA/housekeeping genes, and from 372 core genes of 65 genomes of members of the genus Streptococcus), we propose with confidence that strains HTS9T and HTS12 should be classified as representing a novel species of the genus Streptococcus, Streptococcus halotolerans sp. nov. The type strain is HTS9T (=DSM 101996T=CGMCC1.15532T). Genome analysis of Streptococcus halotolerans sp. nov. shows that its genome is 1 823 556 bp long with a DNA G+C content of 39.9 mol% and contains 2068 genes.

Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China

PubMed Central

Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

2016-01-01

Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively. PMID:26947748

Spatial distribution and source apportionment of PFASs in surface sediments from five lake regions, China

NASA Astrophysics Data System (ADS)

Qi, Yanjie; Huo, Shouliang; Xi, Beidou; Hu, Shibin; Zhang, Jingtian; He, Zhuoshi

2016-03-01

Perfluoroalkyl substances (PFASs) have been found in environment globally. However, studies on PFAS occurrence in sediments of lakes or reservoirs remain relatively scarce. In this study, two hundred and sixty-two surface sediment samples were collected from forty-eight lakes and two reservoirs all over China. Average PFAS concentrations in surface sediments from each lake or reservoir varied from 0.086 ng/g dw to 5.79 ng/g dw with an average of 1.15 ng/g dw. Among five lake regions, average PFAS concentrations for the lakes from Eastern Plain Region were the highest. Perfluorooctanoic acid, perfluoroundecanoic acid and perfluorooctane sulfonic acid (PFOS) were the predominant PFASs in surface sediments. The significant positive correlations between PFAS concentrations and total organic carbon, total nitrogen and total phosphorus contents in sediments revealed the influences of sedimentary characteristics on PFAS occurrence. A two-dimensional hierarchical cluster analysis heat map was depicted to analyze the possible origins of sediments and individual PFAS. The food-packaging, textile, electroplating, firefighting and semiconductor industry emission sources and the precious metals and coating industry emission sources were identified as the main sources by two receptor models, with contributions of 77.7 and 22.3% to the total concentrations of C4-C14- perfluoroalkyl carboxylic acids and PFOS, respectively.

Preliminary study on alterations of altitude road traffic in China from 2006 to 2013

PubMed Central

Zhao, Hui; Yin, Zhiyong; Xiang, Hongyi; Liao, Zhikang; Wang, Zhengguo

2017-01-01

Introduction Road traffic can play an important role in strengthening regional economic activities, especially at high altitude, and it is necessary to know important traffic-related information. Although previous studies reported on road traffic in China, there has been little research on high-altitude road traffic to date. Method The annual official census of road traffic safety from 2006 to 2013 was used to obtain data on the general population, registered drivers, registered vehicles, newly built roads, road traffic accidents (RTAs), mortality rate per 100 000 populations and per 10 000 vehicles in high-altitude provinces, including Tibet, Qinghai, Xinjiang, Gansu, Yunnan, Sichuan, and Chongqing. These provincial data were reviewed retrospectively, with the national data as the reference. Statistical analysis (i.e., t test) was used to compare the estimated average annual change rate of population, number of registered drivers, registered vehicles, and newly built roads in high-altitude provinces with the national rates. Results Compared with the national data, there are significantly higher annual rates of population growth in Tibet and Xinjiang, registered drivers in Gansu, registered vehicles in Gansu, Sichuan, and Chongqing, and newly built roads in Tibet and Qinghai. Among the investigated provinces, Tibet, Qinghai, and Yunnan had a higher proportion of the roads with the high class. RTAs and RTA-induced casualties in the high-altitude provinces indicated a decreasing trend. The mortality rate per 10 000 vehicles and per 100 000 populations showed a decreasing trend, while the RTA-related mortality rate in Tibet, Qinghai, Xinjiang and Gansu remained high. Conclusions Major changes for road traffic in high-altitude provinces have occurred over the past decade; however, the RTA-related mortality rate in high-altitude provinces has remained high. This study furthers understanding about road traffic safety in China; further studies on road traffic safety at

Reconstructing Late Holocene Climate Variability in North East China From Varved Maar Lake Sediments

NASA Astrophysics Data System (ADS)

Panizzo, V. N.; Mackay, A. W.; Rioual, P.; Chu, G.; Leng, M. J.

2008-12-01

Reconstructing climatic variability over the past c. 2 ka years is recognised as a key PAGES timeframe (focus 2). However few high-resolution records exist from the climate sensitive region of N) China which receives the majority of its precipitation from the east Asian summer monsoon (EASM). Interactions between the EASM and the global climate system have great resonance. Such examples include how the EASM responded to changes in climate over the documented e.g. "Medieval Warm Period" (c. AD 900 - 1300), "Little Ice Age" (c. AD 1350-1850) and recent warming. At present, literature remains contradictory to such environmental changes in NE China over this time-frame due to poor chronological control, low resolution of existing studies and even due to the inexact terminology of these climatic periods. Xiaolongwan Lake (XLW) is a small, closed, maar lake located in the Long Gang Volcanic Field, NE China (42°18'N; 126°19'E). It is at an elevation of 655 m a.s.l. with a maximum depth of 15 m. A varve chronology has been created for a 143 cm composite core (2 cores collected in 2006), and here we present diatoms and organic geochemistry (δ13C, TOC, C/N) evidence for environmental change over the past c. 2 ka years. Results show a gradual change in diatom species, moving from a composition where opportunistic species (e.g. Achnanthidium minutissimum) dominate (between c. 100 BC to 500 years AD) at the beginning of the record to one comprised of benthic/epiphytic species (e.g. Staurosira construens var venter, Punctastriata discoidea, Gomphonema parvulum). The introduction after c. 1850 years AD of the planktonic diatom species, Discotella woltereckii, not previously seen in the record, coincides with recent warming. This may be a response to changing limnological conditions, such as decreasing duration of lake ice-cover. Bulk organic δ13C results conducted on a short core collected from XLW in summer 2007, show that over the past c. 350 years there is a distinct

Geochemical Responses to Anthropogenic and Natural Influences in Ebinur Lake Sediments of Arid Northwest China.

PubMed

Ma, Long; Wu, Jinglu; Abuduwaili, Jilili; Liu, Wen

2016-01-01

Geochemical concentrations were extracted for a short sediment core from Ebinur Lake, located in arid northwest China, and mathematical methods were used to demonstrate the complex pattern of the geochemical anomalies resulting from the temporal changes in natural and anthropogenic forces on the lake sediments. The first element assemblage (C1) (aluminum, potassium, iron, magnesium, beryllium, etc.) was predominantly terrigenous; among the assemblage, total phosphorus and titanium were generally consistent with aluminum except with regards to their surface sequences, which inferred the differences of source regions for terrigenous detrital material led to this change around ca. 2000AD. The second assemblage (C2) (calcium and strontium) was found to have a negative relationship with aluminum through a cluster analysis. The third assemblage (C3) included sodium and magnesium, which were influenced by the underwater lake environment and deposited in the Ebinur depression. The concentration ratio of C1/(C1+C2) was used as an indicator for denudation amount of detrital materials, which was supported by the values of magnetic susceptibility. The enrichment factors for heavy metals suggested that the influence of human activities on heavy-metal enrichment in Ebinur Lake region was not severe over the past century. Prior to the 1960s, geochemical indicators suggested a stable lacustrine environment with higher water levels. Beginning in the 1960s, high agricultural water demand resulted in rapid declines in lake water level, with subsequent increases of lake water salinity, as evidenced by enhanced sodium concentration in lake core sediments. During this period, anthropogenic activity also enhanced the intensity of weathering and the denudation of the Ebinur watershed.

Passion: Burning in the West--An Investigation on College Students' Volunteer Teaching in Western China

ERIC Educational Resources Information Center

Zhen, Li

2008-01-01

In this article, the author investigates college students' volunteer teaching in Western China. A series of investigations were conducted in Chongqing, Sichuan, Guizhou, Yunnan, Shanxi, Gansu, Qinghai, Ningxia, and Xinjiang. The results showed that teaching by volunteer college students played a positive role in the development of local education…

Two new species of Haploperla (Plecoptera: Chloroperlidae) from China.

PubMed

Chen, Zhi-Teng; DU, Yu-Zhou

2016-11-23

Two new species of the chloroperline genus Haploperla, H. tuanjiena sp. nov. from Sichuan Province, China and H. datongensis sp. nov. from Qinghai Province, China are described and illustrated. Haploperla tuanjiena is characterized by terga 10 with a medially triangular sclerotized area and the epiproct subtriangular, anterolateral margin sclerotized with apex acute. Haploperla datongensis is characterized by the epiproct tongue-shaped, anterior margin and anteroventrally strongly sclerotized. The new species are compared with similar taxa of the genus. An identification key is provided for the seven known Chinese species of Haploperla.

Occurrence and distribution of antibiotics in surface water impacted by crab culturing: a case study of Lake Guchenghu, China.

PubMed

Wang, Wenxia; Zhou, Lijun; Gu, Xiaohong; Chen, Huihui; Zeng, Qingfei; Mao, Zhigang

2018-05-30

The objective of this study was to evaluate the occurrence, distribution, potential sources, and ecological risk of antibiotics in aqueous phase of Lake Guchenghu, China. Target antibiotics in surface water of Lake Guchenghu, adjacent streams, and crab ponds were detected seasonally. The results showed that erythromycin-H 2 O (1.60-2450 ng/L), sulfadiazine (ND-654 ng/L), and florfenicol (ND-919 ng/L) were the predominant antibiotics in Lake Guchenghu. The concentrations of antibiotics in Lake Guchenghu Basin showed obvious seasonal variation, with the highest concentration in summer. In general, the concentrations of antibiotics in crab ponds and streams were higher than those in the lake and spatial distributions of antibiotics were affected by pollution sources. The types and origins of antibiotics indicated that wastewater from ponds was the main source of antibiotics in the lake. Risk assessment suggested that as individual compound, erythromycin-H 2 O and clarithromycin posed a high risk to algae while other compounds might pose low or no risk. The mixture of antibiotics may pose a high risk to aquatic organisms in Lake Guchenghu. Overall, our study revealed the occurrence and spatiotemporal variation of antibiotics in Lake Guchenghu, which was related with crab culturing.

China Report Economic Affairs

DTIC Science & Technology

1985-02-22

RIBAO, 24 Jan 85) 57 Qinghai Forms Survey Team to Check Economic Reform Progress (Qinghai Provincial Service, 4 Feb 85) 59 Yunnan Raises...Industrial Survey Work (Henan Provincial Service, 4 Feb 85) 109 PRC To Increase Steel Production in 1985 (XINHUA, 2 Feb 85) 110 Briefs Beijing...QINGHAI FORMS SURVEY TEAM TO CHECK ECONOMIC REFORM PROGRESS HK050416 Xining Qinghai Provincial Service in Mandarin 1100 GMT 4 Feb 85 [Text

Evaluation of CDOM sources and their links with water quality in the lakes of Northeast China using fluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Zhao, Ying; Song, Kaishan; Wen, Zhidan; Fang, Chong; Shang, Yingxin; Lv, Lili

2017-07-01

The spatial distributions of the fluorescence intensities Fmax for chromophoric dissolved organic matter (CDOM) components, the fluorescence indices (FI370 and FI310) and their correlations with water quality of 19 lakes in the Songhua River Basin (SHRB) across semiarid regions of Northeast China were examined with the data collected in September 2012 and 2015. The 19 lakes were divided into two groups according to EC (threshold value = 800 μS cm-1): fresh water (N = 13) and brackish water lakes (N = 6). The fluorescent characteristics of CDOM in the 19 lakes were investigated using excitation-emission matrix fluorescence spectroscopy (EEM) coupled with parallel factor (PARAFAC) and multivariate analysis. Two humic-like components (C1 and C3), one tryptophan-like component (C2), and one tyrosine-like component (C4) were identified by PARAFAC. The component C4 was not included in subsequent analyses due to the strong scatter in some colloidal water samples from brackish water lakes. The correlations between Fmax for the three EEM-PARAFAC extracted CDOM components C1-C3, the fluorescence indices (FI370 and FI310) and the water quality parameters (i.e., TN, TP, Chl-a, pH, EC, turbidity (Turb) and dissolved organic carbon (DOC)) were determined by redundancy analysis (RDA). The results of RDA analysis showed that spatial variation in land cover, pollution sources, and salinity/EC gradients in water quality affected Fmax for the fluorescent components C1-C3 and the fluorescence indices (FI370 and FI310). Further examination indicated that the CDOM fluorescent components and the fluorescence indices (FI370 and FI310) did not significantly differ (t-test, p > 0.05) in fresh water (N = 13) and brackish water lakes (N = 6). There was a difference in the distribution of the average Fmax for the CDOM fluorescent components between C1 to C3 from agricultural sources and urban wastewater sources in hypereutrophic brackish water lakes. The Fmax for humic-like components C1 and

Glaciers, Glacial lakes and Glacial Lake Outburst Floods in the Koshi Basin

NASA Astrophysics Data System (ADS)

Shrestha, F.; Gao, X.; Khanal, N. R.; Maharjan, S. B.; Bajracharya, S. R.; Shrestha, R. B.; Lizong, W.; Mool, P. K.

2016-12-01

Glacier is a vital water resources for mountain communities. Recession in glacier area either increased the glacial lake size or develop a new lake. The consequences of these changes in lake has become one of the major issue in the management of GLOF risk. This paper presents the distribution of, and changes in, glaciers, glacial lakes in the Koshi basin and also looks at past GLOF events that have occurred in the basin and their distance of impact. Data on the number of glaciers and glacial lakes and their areas were generated for the years 1977, 1990, 2000, and 2010 using Landsat images. The study revealed that there were a total of 845 glaciers (Nepal side) and 2,168 glacial lakes (Nepal and China side) with a total area of 1,103 km2 and 127.608 km2 in 2010. The number of glacier increased by 15% (109) and area decreased by 26% (396 km2) over 33 years. In case of glacier lakes, the number and area increased from 1,160 to 2,168 and from 94.444 km2 to 127.608 km2 during 33 years with an overall growth rates of 86.9% and 35.1%. A large number of glacial lakes are small in size (≤ 0.1 km2). End moraine dammed lakes with area ≥ 0.1 km2 were selected to analyse the change characteristics of glacial lakes. The results show that there were 134 lakes ≥ 0.1 km2 in 2010; these lakes had a total area of 43.06 km2 in 1997, increased to 64.35 km2 in 2010. The distribution of lakes on the north side of the Himalayas (in China) was three times higher than on the south side of the Himalayas (in Nepal). Comparing the mean growth rate in area and length for the 33 years, the growth rate on the north side was found to be a little slower than that on the south side. This relationship did not hold true for length change in the different periods. The study identified 42 rapidly growing large lakes that are dangerous in terms of GLOF risk. In the past, 18 GLOF events have been reported. The downstream distance impacted by those events was up to 90 km. Among them, 13 GLOF events

[The epidemiology and etiology research of Tibetan sheep plague in Qinghai plateau].

PubMed

Wei, Baiqing; Xiong, Haoming; Yang, Xiaoyan; Yang, Yonghai; Qi, Meiying; Jin, Juan; Xin, Youquan; Li, Xiang; Yang, Hanqing; Han, Xiumin; Dai, Ruixia

2015-03-01

To identify the epidemiology and etiology characteristics of Tibetan sheep plague in Qinghai plateau. The background materials of Qinghai Tibetan sheep plague found during 1975 to 2009 were summarized, the regional, time and interpersonal distribution, infection routes, ecological factors for the spread were used to analyze; followed by choosing 14 Yersinia pestis strains isolated from such sheep for biochemical test, toxicity test, virulence factors identification, plasmid analysis, and DFR genotype. From 1975 to 2009, 14 Yersinia pestis strains were isolated from Tibetan sheep in Qinghai province. Tibetan sheep, as the infection source, had caused 10 cases of human plague, 25 plague patients, and 13 cases of death. All of the initial cases were infected due to eating Tibetan sheep died of plague; followed by cases due to contact of plague patients, while all the initial cases were bubonic plague. Cases of bubonic plague developed into secondary pneumonic plague and septicemia plague were most popular and with high mortality. Most of the Tibetan sheep plague and human plague occurred in Gannan ecological zone in southern Gansu province, which was closely related to its unique ecological and geographical landscape. Tibetan sheep plague coincided with human plague caused by Tibetan sheep, especially noteworthy was that November (a time for marmots to start their dormancy) witnesses the number of Yersinia pestis strains isolated from Tibetan sheep and human plague cases caused by Tibetan sheep. This constituted the underlying cause that the epidemic time of Tibetan sheep plague lags obviously behind that of the Marmot plague. It was confirmed in the study that all the 14 strains were of Qinghai-Tibet Plateau ecotype, with virulence factors evaluation and toxicity test demonstrating strains as velogenic. As found in the (Different Region) DFR genotyping, the strains isolated from Yushu county and Zhiduo county were genomovar 5, the two strain isolated from Nangqian

Research on Synchronous Coordination Development of Tourism-Economy-Environment System in Qinghai Section of Silk Road

NASA Astrophysics Data System (ADS)

Xue, Huaju

2018-01-01

Using coupling theory in physics, the paper analyzed the relationship of coordinated development of tourism-economy-environment system (abbr. TEES) in Qinghai. Results showed the comprehensive evaluation of Qinghai TEES has been improved greatly from 2000 to 2014. However, coupling degree has still been in the running-in stage and coordination degree only arrives at the primary coordination level, the development of economy and tourism has exceeded the threshold of ecological environment after 2008, and the ecological environment has become the bottleneck restricting the further improvement of coupling coordination. In the future, Qinghai must change its mode of development and focus on industrial upgrading and transformation so as to promote the harmonious and sustainable development of TEES in the Silk Road.

Historical Records and Source Apportionment of Polycyclic Aromatic Hydrocarbons Over the Past 100 Years in Dianchi Lake, a Plateau Lake in Southwest China.

PubMed

Ma, Xiaohua; Han, Xiuxiu; Jiang, Quanliang; Huang, Changchun; Huang, Tao; Yang, Hao; Yao, Ling

2018-04-12

Two sediment cores were collected from Dianchi Lake, a plateau lake in Southwest China, to study the temporal trends and to investigate the sources of sedimentary deposited polycyclic aromatic hydrocarbon. The ΣPAH16 concentration in the two sediment cores ranged from 172.5 to 2244.8 ng/g and from 211.4 to 1777.8 ng/g, with mean values of 1106.2 and 865.1 ng/g, respectively. Three temporal trends for the ΣPAH16 concentration and the composition of PAHs in Dianchi Lake all showed three typical changing stages: (1) slight changes in deeper segments before the 1950s; (2) a rapid increase in PAH concentrations between the 1960s and 1990s; and (3) a slight reduction from the 1990s onward. These trends differ from those observed in developed countries due to differences in the timing of industrialization and urbanization processes. According to the results of the molecular ratios and principal component analysis, the PAH deposition was dominated by coal combustion, wood combustion, and vehicle emissions before and after the 1960s, respectively.

Victims and vectors: highly pathogenic avian influenza H5N1 and the ecology of wild birds

USGS Publications Warehouse

Takekawa, John Y.; Prosser, Diann J.; Newman, Scott H.; Muzaffar, Sabir Bin; Hill, Nichola J.; Yan, Baoping; Xiao, Xiangming; Lei, Fumin; Li, Tianxian; Schwarzbach, Steven E.; Howell, Judd A.

2010-01-01

The emergence of highly pathogenic avian influenza (HPAI) viruses has raised concerns about the role of wild birds in the spread and persistence of the disease. In 2005, an outbreak of the highly pathogenic subtype H5N1 killed more than 6,000 wild waterbirds at Qinghai Lake, China. Outbreaks have continued to periodically occur in wild birds at Qinghai Lake and elsewhere in Central China and Mongolia. This region has few poultry but is a major migration and breeding area for waterbirds in the Central Asian Flyway, although relatively little is known about migratory movements of different species and connectivity of their wetland habitats. The scientific debate has focused on the role of waterbirds in the epidemiology, maintenance and spread of HPAI H5N1: to what extent are they victims affected by the disease, or vectors that have a role in disease transmission? In this review, we summarise the current knowledge of wild bird involvement in the ecology of HPAI H5N1. Specifically, we present details on: (1) origin of HPAI H5N1; (2) waterbirds as LPAI reservoirs and evolution into HPAI; (3) the role of waterbirds in virus spread and persistence; (4) key biogeographic regions of outbreak; and (5) applying an ecological research perspective to studying AIVs in wild waterbirds and their ecosystems.

Scenario analysis of the impacts of socioeconomic development on phosphorous export and loading from the Dongting Lake watershed, China.

PubMed

Hou, Ying; Chen, Weiping; Liao, Yuehua; Luo, Yueping

2017-12-01

Socioeconomic development in lake watersheds is closely related with lake nutrient pollution. As the second largest freshwater lake in China, the Dongting Lake has been experiencing an increase in nutrient loading and a growing risk of eutrophication. This study aimed to reveal the likely impacts of the socioeconomic development of the Dongting Lake watershed on the phosphorous pollution in the lake. We estimated the contributions from different sources and sub-watersheds to the total phosphorous (TP) export and loading from the Dongting Lake watershed under two most likely socioeconomic development scenarios. Moreover, we predicted the likely permissible and actual TP loadings to the Dongting Lake. Under both two scenarios, three secondary sub-watersheds-the upper and lower reaches of the Xiang River watershed and the Dongting Lake Area-are expected to dominate the contribution to the TP export from the Dongting Lake watershed in 2020. Three primary sub-watersheds-the Dongting Lake Area, the Xiang River, and the Yuan River watersheds-are predicted to be the major contributors to the TP loading from the entire watershed. The two scenarios are expected to have a slight difference in TP export and lake TP loading. Livestock husbandry is expected to be the predominant anthropogenic TP source in each of the sub-watersheds under both scenarios. Compared to 2010, permissible TP loading is not expected to increase but actual TP loading is predicted to grow significantly in 2020. Our study provides methodologies to identify the key sources and regions of lake nutrient loading from watersheds with complex socioeconomic context, and to reveal the potential influences of socioeconomic development on nutrient pollution in lake watersheds.

Assessment of Heavy Metal Pollution in Sediments of Inflow Rivers to Lake Taihu, China.

PubMed

Niu, Yong; Niu, Yuan; Pang, Yong; Yu, Hui

2015-11-01

Lake Taihu, the third-largest freshwater body in China, has many functions, including drinking water supply, flood control, cultivation, navigation, and tourism. In this study, sediment samples were collected at 31 sites from 11 inflow rivers in 2012, to investigate the distribution and concentration of heavy metals copper (Cu), zinc (Zn), lead (Pb), nickel (Ni), and chromium (Cr), and to assess their potential ecological risk. The highest mean concentration was found for Zn, followed by Cu, Cr, Pb, and Ni. Generally, heavy metal pollution was more serious in Wu Jingang River and Caoqiao River, probably because they receive large amounts of wastewater from various local industrial enterprises. The potential ecological risk values of the heavy metals were larger than 120 in more than 25.8% of the sediment samples, indicating a very high risk. The largest ecological risk was due to copper. Furthermore, the results of a principal component analysis and subsequent analysis of variance showed that heavy metal concentrations in the sediment of inflow rivers were higher than those of the lake, which created a large hazard for the aquatic ecosystems of Lake Taihu.

Flooding in Central China

NASA Technical Reports Server (NTRS)

2002-01-01

During the summer of 2002, frequent, heavy rains gave rise to floods and landslides throughout China that have killed over 1,000 people and affected millions. This false-color image of the western Yangtze River and Dongting Lake in central China was acquired on August 21, 2002, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. (right) The latest flooding crisis in China centers on Dingtong Lake in the center of the image. Heavy rains have caused it to swell over its banks and swamp lakefront towns in the province of Hunan. As of August 23, 2002, more than 250,000 people have been evacuated, and over one million people have been brought in to fortify the dikes around the lake. Normally the lake would appear much smaller and more defined in the MODIS image. Credit: Image courtesy Jacques Descloitres, MODIS Land Rapid Response Team at NASA GSFC.

Wind-induced flow velocity effects on nutrient concentrations at Eastern Bay of Lake Taihu, China.

PubMed

Jalil, Abdul; Li, Yiping; Du, Wei; Wang, Jianwei; Gao, Xiaomeng; Wang, Wencai; Acharya, Kumud

2017-07-01

Shallow lakes are highly sensitive to respond internal nutrient loading due to wind-induced flow velocity effects. Wind-induced flow velocity effects on nutrient suspension were investigated at a long narrow bay of large shallow Lake Taihu, the third largest freshwater lake in China. Wind-induced reverse/compensation flow and consistent flow field probabilities at vertical column of the water were measured. The probabilities between the wind field and the flow velocities provided a strong correlation at the surface (80.6%) and the bottom (65.1%) layers of water profile. Vertical flow velocity profile analysis provided the evidence of delay response time to wind field at the bottom layer of lake water. Strong wind field generated by the west (W) and west-north-west (WNW) winds produced displaced water movements in opposite directions to the prevailing flow field. An exponential correlation was observed between the current velocities of the surface and the bottom layers while considering wind speed as a control factor. A linear model was developed to correlate the wind field-induced flow velocity impacts on nutrient concentration at the surface and bottom layers. Results showed that dominant wind directions (ENE, E, and ESE) had a maximum nutrient resuspension contribution (nutrient resuspension potential) of 34.7 and 43.6% at the surface and the bottom profile layers, respectively. Total suspended solids (TSS), total nitrogen (TN), and total phosphorus (TP) average concentrations were 6.38, 1.5, and 0.03 mg/L during our field experiment at Eastern Bay of Lake Taihu. Overall, wind-induced low-to-moderate hydrodynamic disturbances contributed more in nutrient resuspension at Eastern Bay of Lake Taihu. The present study can be used to understand the linkage between wind-induced flow velocities and nutrient concentrations for shallow lakes (with uniform morphology and deep margins) water quality management and to develop further models.

Temporal and spatial changes of water quality and management strategies of Dianchi Lake in southwest China

NASA Astrophysics Data System (ADS)

Zhang, T.; Zeng, W. H.; Wang, S. R.; Ni, Z. K.

2014-04-01

Temporal and spatial changes to the water quality of Dianchi Lake in southwest China were investigated using monthly monitoring data from 2005 to 2012. Dianchi Lake is divided into two parts, Caohai Lake and Waihai Lake, by a man-made dike. Caohai Lake lies at the north of Dianchi Lake, while Waihai Lake is the main water body of Dianchi Lake and accounts for 96.7% of the whole area of the lake. Based on the analysis of total phosphorus (TP), total nitrogen (TN), and chlorophyll a (Chl a) concentrations, it was determined that, in Caohai Lake, the annual concentrations of these variables ranged from 0.19-1.46 mg L-1, 6.11-16.79 mg L-1, 0.06-0.14 mg L-1, respectively. In addition, the annual concentrations of TP, TN and Chl a in Waihai Lake ranged between 0.13 and 0.20 mg L-1, 1.82 and 3.01 mg L-1, and 0.04 and 0.09 mg L-1, respectively. Cluster analysis (CA) classified the 10 monitoring sites into two clusters (cluster A and cluster B) based on similarities of water quality characteristics. Our data revealed that the current status of water quality within Caohai Lake was much worse than that of Waihai Lake. Water quality was seriously degraded during the economic boom near the period of the "Eleventh Five-Year Plan" (2005-2010), and gradually improved from 2010 to 2012 because of the "standard emission directive to industry". The main factors that influenced the spatial and temporal changes to water quality were natural factors including lake evolution and regional characteristic as well as human factors such as pollution load into the lake and management strategies that were already adopted. Some activities and regulations were implemented to enhance the lake environment by controlling wastewater emissions and establishing regulations to protect the lakes in the Yunnan Province. However, problems with institutional fragmentation (horizontal and vertical), simple treatment methods, low-intensity investment in pollution control, and lack of meaningful endogenous

An improved model for soil surface temperature from air temperature in permafrost regions of Qinghai-Xizang (Tibet) Plateau of China

NASA Astrophysics Data System (ADS)

Hu, Guojie; Wu, Xiaodong; Zhao, Lin; Li, Ren; Wu, Tonghua; Xie, Changwei; Pang, Qiangqiang; Cheng, Guodong

2017-08-01

Soil temperature plays a key role in hydro-thermal processes in environments and is a critical variable linking surface structure to soil processes. There is a need for more accurate temperature simulation models, particularly in Qinghai-Xizang (Tibet) Plateau (QXP). In this study, a model was developed for the simulation of hourly soil surface temperatures with air temperatures. The model incorporated the thermal properties of the soil, vegetation cover, solar radiation, and water flux density and utilized field data collected from Qinghai-Xizang (Tibet) Plateau (QXP). The model was used to simulate the thermal regime at soil depths of 5 cm, 10 cm and 20 cm and results were compared with those from previous models and with experimental measurements of ground temperature at two different locations. The analysis showed that the newly developed model provided better estimates of observed field temperatures, with an average mean absolute error (MAE), root mean square error (RMSE), and the normalized standard error (NSEE) of 1.17 °C, 1.30 °C and 13.84 %, 0.41 °C, 0.49 °C and 5.45 %, 0.13 °C, 0.18 °C and 2.23 % at 5 cm, 10 cm and 20 cm depths, respectively. These findings provide a useful reference for simulating soil temperature and may be incorporated into other ecosystem models requiring soil temperature as an input variable for modeling permafrost changes under global warming.

Trimethylamine stimulated and dissolved organic matter inhibited methane production in sediment from the Poyang Lake, China.

PubMed

Wang, Jiajia; Liu, Chunying; Gong, Xiaofeng; Liu, Yuanmu; Chen, Chunli

2016-10-01

Methane (CH4) emitted from wetlands contributes significantly to the greenhouse effect. The Poyang Lake, the largest freshwater lake in China, is fed by five rivers and connects to the Yangtze River. The area of the lake fluctuates dramatically between drawdown and flood periods with large areas of wetlands. In order to understand the CH4 production capacity and factors that influence CH4 production in the wetland, a static closed chamber combined with a gas chromatograph technique was used to investigate the influence of substrates and electron acceptors on methanogenesis. The results showed that CH4 production capacity of sediments from the Poyang Lake was [Formula: see text] and it was stimulated by trimethylamine (TMA) to a great extent. Incubation temperature played a vital role on CH4 production in sediments and the optimum temperature for methanogenesis was 35°C. Minimum CH4 production capacity occurred with the addition of FeCl3, and the inhibitory effects of electron acceptors decreased in the sequence: FeCl3 > MnO2 > DOM > Fe2O3. In this study, DOM was demonstrated as one of the inhibitors to methanogenesis and TMA was the main substrate of methanogens in the sediments of the Poyang Lake whose pH value is 7.83.

[Burden of disease attributable to high- sodium diets in China, 2013].

PubMed

Liu, M; Li, Y C; Liu, S W; Wang, L J; Liu, Y N; Yin, P; Liu, J M; You, J L; Zhou, M G

2016-09-06

Objective: To examine the burden of disease(BOD)attributable to high-sodium diets in China in 2013. Methods: Data were extracted from the 2013 Global Burden of Disease Study for China to examine the BOD attributable to high-sodium diets in 2013, gender, and disease composition. Measurements for attributable BOD were population attributable fraction(PAF), deaths, standardized mortality and disability-adjusted life years(DALY)(not including Taiwan, China). An average world population age-structure for the period 2000-2025 was adopted to calculate age-standardized rates. Results: In 2013, deaths attributable to high-sodium diets accounted for 12.6% of all deaths and 14.5% of chronic disease deaths. Overall, 7.8% of deaths because of neoplasms, 25.2% of cardiovascular disease deaths, and 22.9% of chronic kidney disease deaths were attributable to high-sodium diets. A total of 1 176 553 deaths were attributable to high-sodium diets and the standardized mortality was 91.5/100 000, which was higher in men than in women(121.7/100 000 and 63.0/100 000, respectively). Overall, 22.759 million DALYs were attributable to high-sodium diets. The DALY standardized rate was 1 588.0/100 000, which was higher in men than in women(2 189.7/100 000 and 993.2/100 000, respectively). When compared by province, PAF in Xinjiang(25.0%), Qinghai(23.7%), Shanxi(23.2%), Tibet(22.1%)and Shandong(20.5%)was higher than other provinces. The standardized mortality in Xinjiang(239.4/100 000), Qinghai(238.9/100 000), Tibet(221.7/100 000), Shanxi(166.2/100 000)and Hebei(149.9/100 000)were higher than other provinces. The DALY standardized rate attributable to high-sodium diets was highest in Xinjiang(4 430.8/100 000), Qinghai(4 422.5/100 000), Tibet(4 021.4/100 000), Shanxi(2 816.6/100 000), and Hebei(2 624.9/100 000). Conclusion: The BOD attributable to high-sodium diets is a serious issue in China, particularly in men and in the northern provinces. Effective measures should be taken in northern

Pore Effect on the Occurrence and Formation of Gas Hydrate in Permafrost of Qilian Mountain, Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Gao, H.; Lu, H.; Lu, Z.

2014-12-01

Gas hydrates were found in the permafrost of Qilian Mountain, Qinghai- Tibet Plateau, China in 2008. It has been found that gas hydrates occur in Jurassic sedimentary rocks, and the hydrated gases are mainly thermogenic. Different from the gas hydrates existing in loose sands in Mallik, Mackenzie Delta, Canada and North Slope, Alaska, USA, the gas hydrates in Qilian Mountain occurred in hard rocks. For understanding the occurrence and formation mechanism of gas hydrate in hard rcok, extensive experimental investigations have been conducted to study the pore features and hydrate formation in the rocks recovered from the hydrate layers in Qilian Mountain. The structures of sedimentary rock were observed by high-resolution X-ray CT, and pore size distribution of a rock specimen was measured with the mercury-injection method. Methane hydrate was synthesized in water-saturated rocks, and the saturations of hydrate in sedimentary rocks of various types were estimated from the amount of gas released from certain volume of rock. X-ray CT observation revealed that fractures were developed in the rocks associated with faults, while those away from faults were generally with massive structure. The mercury-injection analysis of pore features found that the porosities of the hydrate-existing rocks were generally less than 3%, and the pore sizes were generally smaller than 100 nm. The synthesizing experiments found that the saturation of methane hydrate were generally lower than 6% of pore space in rocks, but up to 16% when fractures developed. The low hydrate saturation in Qilian sedimentary rocks has been found mainly due to the small pore size of rock. The low hydrate saturation in the rocks might be the reason for the failure of regional seismic and logging detections of gas hydrates in Qilian Mountain.

Nutrient Characterization of Rainwater, Soil and Groundwater from Two Different Watersheds, Lake Taihu, China

NASA Astrophysics Data System (ADS)

Thaw, M.; Gao, F.; Yu, Z.; Acharya, K.

2012-12-01

Over the past two decades, an increase of nutrients to Lake Taihu, China has resulted in hyper-eutrophication and the production of severe cyanobacterial blooms. While many past studies have focused on how surface water transports nutrients to the lake, this study seeks to characterize the concentration of nutrients in different media, including rainwater, soil and groundwater from two different watersheds. These two watersheds varied in overall land use, and agricultural sites within each watershed varied by crop type and growing method. Samples were collected from the Meilin watershed, a mix of forest and agricultural land and the Zhangjiagang watershed, which consisted of industrial, urban and agricultural lands. Samples included soils, groundwater and rain water. Soils from each site were characterized by aggregate size class and analyzed for total nitrogen and total phosphorus. Rainwater and groundwater samples were analyzed for total nitrogen and total phosphorus.

Lake evolution of the terminal area of Shiyang River drainage in arid China since the last glaciation

USGS Publications Warehouse

Shi, Q.; Chen, F.-H.; Zhu, Y.; Madsen, D.

2002-01-01

Investigations of geomorphology and sedimentology, and analyses of radiocarbon dates, grain size and carbonate of the sediment at the present-dry closed basin in the terminal area of Shiyang River in arid China were conducted to recover the history of palaeolake change since the last glacial. The terminal area was covered by eolian sand before 13,000 14C BP. Lacustrine deposits covered the eolian sand after 13,000 14C BP, but were succeeded rapidly by eolian or fluvial deposits ca. 11,200-10,000 BP. This fact plus the grain-size distribution and CaCO3 content showed that climate was extremely dry during the last glacial, but wet-dry oscillations characterized the late glacial. A single coalescent lake, over 45 m deep and 2130 km2, formed between 10,000-6400 14C BP in the basin. The lake disintegrated into several shallow carbonate lakes or swamps gradually after 6400 14C BP. Eolian sand reached into the most part of the basin during the period. The lake evolution in the area generally reflects the East Asian summer monsoon history forced by Northern hemisphere insolation. Short time-scale lake fluctuations also existed in the area since the last glacial. ?? 2002 Elsevier Science Ltd and INQUA. All rights reserved.

BrGDGT-based quantitative temperature reconstruction over the past 2000 years from an alpine lake in subtropical southwestern China

NASA Astrophysics Data System (ADS)

Zhao, C.; Feng, X.

2017-12-01

BrGDGTs have been proposed as a proxy for quantitative paleotemperature reconstructions in terrestrial environment, and numerous transfer functions have been framed based on modern soils and lake sediments. However, these spatial-based functions have been seldom successful for paleotemperature reconstructions in lake sediments. In this study, we report a quantitative temperature record over the past 2000 years, using a temporal-based transfer function inferred from branched GDGTs from a sediment core collected at a small alpine lake (Tiancai lake, 26°38'E, 99°43'N, 3898 m asl) in a remote location in subtropical southwestern China. The chronology is established by both 210Pb and AMS-14C dating methods. We find a significant correlation between brGDGT distributions and instrumental mean annual air temperature (MAAT) (R2=0.902, p<0.0001) over the past 60 years. We then establish a local instrumental calibration and apply it to the entire core for MAAT reconstruction over the past 2000 years. Our preliminary results show the reconstructed MAAT varies between -0.77 and 4.13° over the past 2000 years. Our data indicate four warm intervals at 20-142AD, 321-578AD, 796-1215AD and after 1940AD, and four cold intervals at 158-321AD, 550-657AD, 1500-1727AD, 1810-1912AD. The warm period at 796-1215AD and the cold period at 1500-1727AD are likely corresponding with the Medieval Climate Anomaly (MCA) and the Little Ice Age (LIA), respectively, which is consistent with published data in northern China and the northern Hemisphere. Our preliminary result indicates that this temporal-based calibration could be more practical in some environmental-stable open lakes, and also suggests coherent temperature changes in the subtropical and high-latitude northern hemisphere over the past 2000 years.

Dynamics of the lakes in the middle and lower reaches of the Yangtze River basin, China, since late nineteenth century.

PubMed

Cui, Lijuan; Gao, Changjun; Zhao, Xinsheng; Ma, Qiongfang; Zhang, Manyin; Li, Wei; Song, Hongtao; Wang, Yifei; Li, Shengnan; Zhang, Yan

2013-05-01

The middle and lower reaches of the Yangtze River basin have the most representative and largest concentration of freshwater lakes in China. However, the size and number of these lakes have changed considerably over the past century due to the natural and anthropogenic impact. The lakes, larger than 10 km(2) in size, were chosen from relief maps and remotely sensed images in 1875, 1950, 1970, 1990, 2000, and 2008 to study the dynamics of lakes in the middle and lower reaches of the Yangtze River basin and to examine the causes and consequences of these changes. Results indicated that there was a dramatic reduction in lake areas, which decreased by 7,841.2 km(2) (42.64 %) during the study period (1875-2008), and the number of lakes in this region changed moderately. Meanwhile, a large number of lakes in the middle and lower reaches of the Yangtze River basin were directly converted into paddy fields, ponds, building lands, or other land-use types over the study period. Therefore, all kinds of lake reclamation should be identified as the major driving factors for the loss of lake in this region. Furthermore, flooding, soil erosion, and sedimentation were also the main factors which triggered lake changes in different periods. Some wetland conservation and restoration projects have been implemented since the 1970s, but they have not reversed the lake degradation. These findings were of great importance to managers involved in making policy for the conservation of lake ecosystems and the utilization of lake resources.

Tracking four-decade inundation changes with multi-temporal satellite images in China's largest freshwater lake

NASA Astrophysics Data System (ADS)

Wu, Guiping

2017-04-01

Poyang Lake is the largest freshwater lake in China. The lake has undergone remarkable spatio-temporal changes in both short- and long-term scales since 1970s, resulting in significant hydrological, ecological and economic consequences. Remote sensing techniques have advantages for large-scale studies, by offering images at different spatial and spectral resolutions. However, due to technical difficulties, no single satellite sensor can meet the needs for high spatio-temporal resolution required for such monitoring. In this study, using Landsat Thematic Mapper (TM) and Moderate Resolution Imaging Spectroradiometer (MODIS) images collected between 1973 and 2012, we documented and investigated the short- and long-term characteristics of lake inundation based on Normalized Difference Water Index (NDWI). First, we presented a novel downscaling method based on the NDWI statistical regression algorithm to generate small-scale resolution inundation map (30m) from coarse MODIS data (500m). The downscaling is a linear calibration of the NDWI index from MODIS imagery to Landsat imagery, which is based on the assumption that the relationships between fine resolution and coarse resolution are invariable. Second, Tupu analysis method was further performed to explore the spatial-temporal distribution and changing processes of lake inundation based on downscaling inundation maps. Then, a defined water variation rate (WVR) and inundation frequency (IF) indicator was used to reveal seasonal water surface submersion/exposure processes of lake expansion and shrinkage in different zones. Finally, mathematical statistics methods were utilized to explore the possible driving mechanisms of the revealed change patterns with meteorological data and hydrological data. The results show that, there is a high correlation (mean absolute error of 3.95% and an R2 of 0.97) between the MODIS- and Landsat-derived water surface areas in Poyang Lake. Over the past 40 years, a declining trend to a

Bioaccumulation and trophic transfer of mercury in a food web from a large, shallow, hypereutrophic lake (Lake Taihu) in China.

PubMed

Wang, Shaofeng; Li, Biao; Zhang, Mingmei; Xing, Denghua; Jia, Yonfeng; Wei, Chaoyang

2011-08-01

Due to the fast development of industry and the overuse of agrichemicals in past decades, Lake Taihu, an important source of aquatic products for Eastern China, has simultaneously suffered mercury (Hg) contamination and eutrophication. The objectives of this study are to understand Hg transfer in the food web in this eutrophic, shallow lake and to evaluate the exposure risk of Hg through fish consumption. Biota samples including macrophytes, sestons, benthic animals, and fish were collected from Lake Taihu in the fall of 2009. The total mercury (THg), methyl mercury (MeHg), δ(13)C and δ(15)N in the samples were measured. The signature for δ(15)N increased with the trophic levels. Along with a diet composed of fish, the significant relationship between the δ(13)C and δ(15)N indicated that a pelagic foraging habitat is the dominant pathway for energy transfer in Lake Taihu. The concentrations of THg and MeHg in the organisms varied dramatically by ∼3 orders of magnitude from primary producers (macrophytes and sestons) to piscivorous fish. The highest concentrations of both THg (100 ng g(-1)) and MeHg (66 ng g(-1)), however, were lower than the guideline of 200 ng g(-1) of MeHg for vulnerable populations that is recommended by the World Health Organization (WHO). The daily intake of THg and MeHg of 92 and 56 ng day(-1) kg(-1) body weight, respectively, was generally lower than the tolerable intake of 230 ng day(-1) kg(-1) body weight for children recommended by the Joint FAO/WHO Expert Committee on Food Additives. Significant relationships between the δ(15)N and the logarithm of THg and MeHg showed an obvious biomagnification of Hg along the food web. The logarithmic bioaccumulation factor of MeHg in the fish (up to 5.7) from Lake Taihu, however, was relatively low compared to that of other aquatic ecosystems. Health risk of exposure to Hg by consumption of fish for local residents is relatively low in the Lake Taihu area. Dilution of Hg levels in

The community structure and seasonal dynamics of plankton in Bange Lake, northern Tibet, China

NASA Astrophysics Data System (ADS)

Zhao, Wen; Zhao, Yuanyi; Wang, Qiaohan; Zheng, Mianping; Wei, Jie; Wang, Shan

2016-11-01

The seasonal variations in biomass, abundance, and species composition of plankton in relation to hydrography were studied in the saline Bange Lake, northern Tibet, China. Sampling was carried out between one to three times per month from May 2001 to July 2002. Salinity ranged from 14 to 146. The air and water temperature exhibited a clear seasonal pattern, and mean annual temperatures were approximately 4.8°C and 7.3°C, respectively. The lowest water temperature occurred in winter from December to March at -2°C and the highest in June and July at 17.7°C. Forty-one phytoplankton taxa, 21 zooplankton, and 5 benthic or facultative zooplankton were identified. The predominant phytoplankton species were Gloeothece linearis, Oscillatoria tenuis, Gloeocapsa punctata, Ctenocladus circinnatus, Dunaliella salina, and Spirulina major. The predominant zooplankton species included Holophrya actra, Brachionus plicatilis, Daphniopsis tibetana, Cletocamptus dertersi, and Arctodiaptomus salinus. The mean annual total phytoplankton density and biomass for the entire lake were 4.52×107 cells/L and 1.60 mg/L, respectively. The annual mean zooplankton abundance was 52, 162, 322, and 57, 144 ind./L, in the three sublakes. The annual mean total zooplankton biomass in Lakes 1-3 was 1.23, 9.98, and 2.13 mg/L, respectively. The annual mean tychoplankton abundances in Bg1, 2, and 3 were 47, 67, and 654 ind./L. The annual mean tychoplankton biomass was 2.36, 0.16, and 2.03 mg/L, respectively. The zooplankton biomass (including tychoplankton) in the lake was 9.11 mg/L. The total number of plankton species in the salt lake was significantly negatively correlated with salinity.

New species and records of Lobrathium Mulsant & Rey (Coleoptera, Staphylinidae, Paederinae) from China

PubMed Central

Li, Wen-Rong; Zhao, Mei-Jun; Dai, Cong-Chao; Li, Li-Zhen

2013-01-01

Abstract Seven new species of the genus Lobrathium Mulsant & Rey from China are described and illustrated: Lobrathium anatinum Li & Li, sp. n. (Guangxi), Lobrathium diaoluoense Li & Li, sp. n. (Hainan), Lobrathium dufui Li & Li, sp. n. (Hubei), Lobrathium lirunyui Li & Li, sp. n. (Guizhou), Lobrathium pengi Li & Li, sp. n. (Guangxi), Lobrathium quyuani Li & Li, sp. n. (Hubei) and Lobrathium uncinatum Li & Li, sp. n. (Qinghai). A recent key to the species of mainland China is modified to accommodate the new species. New locality data are provided for eleven species. PMID:23794908

Temporal and spatial changes of water quality and management strategies of Dianchi Lake in southwest China

NASA Astrophysics Data System (ADS)

Zhang, T.; Zeng, W. H.; Wang, S. R.; Ni, Z. K.

2013-12-01

Temporal and spatial changes to the water quality of Dianchi Lake in Southwest China were investigated using monthly monitoring data from 2005 to 2012. Based on the analysis of total phosphorus (TP), total nitrogen (TN), and chlorophyll a (Chl a) concentrations, it was determined that, in Caohai Lake, the annual concentrations of these variables ranged from 0.19-1.46, 6.11-16.79, 0.06-0.14 mg L-1, respectively. In addition, the annual concentrations of TP, TN and Chl a in Waihai Lake ranged between 0.13-0.20, 1.82-3.01, 0.04-0.09 mg L-1, respectively. Cluster Analysis (CA) classified the 10 monitoring sites into two groups (group A and group B) based on similarities of water quality characteristics. Our data revealed that the current status of water quality within Caohai Lake was much worse than that of Waihai Lake. Water quality was seriously degraded during the economic boom near the period of the "Eleventh Five-Year Plan" (2005-2010), and gradually improved from 2010 to 2012 because of the "standard emission directive to industry". The main factors that influenced the spatial and temporal changes to water quality were natural factors including lake evolution and regional characteristic as well as human factors such as pollution load into the lake and management strategies that were already adopted. Some activities and regulations were implemented to enhance the lake environment by controlling wastewater emissions and establishing regulations to protect the lakes in the Yunnan Province. However, problems with institutional fragmentation (horizontal and vertical), simple treatment methods, low-intensity investment in pollution control, and lack of meaningful endogenous pollution control strategies were still present in the lake management strategy. To solve these problems, suitable control measures are needed, especially considering the current old-age status of Dianchi Lake. The fundamental improvement of the water quality within Caohai Lake was dependent on the

Combined use of radiocarbon and stable carbon isotope to constrain the sources and cycling of particulate organic carbon in a large freshwater lake, China.

PubMed

Chen, Jingan; Yang, Haiquan; Zeng, Yan; Guo, Jianyang; Song, Yilong; Ding, Wei

2018-06-01

The concentrations and isotopic compositions of dissolved inorganic carbon (DIC) and particulate organic carbon (POC) were measured in order to better constrain the sources and cycling of POC in Lake Fuxian, the largest deep freshwater lake in China. Model results based on the combined δ 13 C and Δ 14 C, showed that the average lake-wide contributions of autochthonous POC, terrestrial POC, and resuspended sediment POC to the bulk POC in Lake Fuxian were 61%, 22%, and 17%, respectively. This indicated autochthonous POC might play a dominant role in sustaining large oligotrophic lake ecosystem. A mean 17% contribution of resuspended sediment POC to the bulk POC implied that sediment might have more significant influence on aquatic environment and ecosystem than previously recognized in large deep lakes. The contributions of different sources POC to the water-column POC were a function of the initial composition of the source materials, photosynthesis, physical regime of the lake, sediment resuspension, respiration and degradation of organic matter, and were affected indirectly by environmental factors such as light, temperature, DO, wind speed, turbidity, and nutrient concentration. This study is not only the first systematic investigation on the radiocarbon and stable isotope compositions of POC in large deep freshwater lake in China, but also one of the most extensive radiocarbon studies on the ecosystem of any great lakes in the world. The unique data constrain relative influences of autochthonous POC, terrestrial POC, and resuspended sediment POC, and deepen the understanding of the POC cycling in large freshwater lakes. This study is far from comprehensive, but it serves to highlight the potential of combined radiocarbon and stable carbon isotope for constraining the sources and cycling of POC in large lake system. More radiocarbon investigations on the water-column POC and the aquatic food webs are necessary to illuminate further the fate of autochthonous POC

Some potential hazardous trace elements contamination and their ecological risk in sediments of western Chaohu Lake, China.

PubMed

Zheng, Liu-Gen; Liu, Gui-Jian; Kang, Yu; Yang, Ren-Kang

2010-07-01

The Chaohu is one of the largest five freshwater lakes in China. It provides freshwater for agriculture, life, and part of industry. The quality of water becomes worst and worst due to the toxic matter. In this study, we collected the samples from the sedimentary mud in the lake. The distribution of some potential hazardous trace elements (Cu, Ni, Cr, As, Pb, Cd, and Hg) in the sediments of western Chaohu Lake, has been determined and studied, and the enrichment factors, the index of geoaccumulation, and potential ecological risk were analyzed and calculated. The results show that: the levels of selected potential hazardous trace element vary from different sampling sites and significant anthropogenic impact of Pb and Cd occur in sediments. The contamination rank of Pb and Cd are moderate, and Pb has a light potential ecological risk, but Cd is heavy. The total potential ecological risk of the selected hazardous trace elements in this study in Chaohu Lake is moderate. Cluster and correlation analysis indicate that the selected potential hazardous trace element pollutant has different source and co-contamination also occur in sediments.

Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory

NASA Astrophysics Data System (ADS)

Wang, Ce; Bi, Jun; Fath, Brian D.

2017-02-01

A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained.

Effects of abiotic factors on ecosystem health of Taihu Lake, China based on eco-exergy theory

PubMed Central

Wang, Ce; Bi, Jun; Fath, Brian D.

2017-01-01

A lake ecosystem is continuously exposed to environmental stressors with non-linear interrelationships between abiotic factors and aquatic organisms. Ecosystem health depicts the capacity of system to respond to external perturbations and still maintain structure and function. In this study, we explored the effects of abiotic factors on ecosystem health of Taihu Lake in 2013, China from a system-level perspective. Spatiotemporal heterogeneities of eco-exergy and specific eco-exergy served as thermodynamic indicators to represent ecosystem health in the lake. The results showed the plankton community appeared more energetic in May, and relatively healthy in Gonghu Bay with both higher eco-exergy and specific eco-exergy; a eutrophic state was likely discovered in Zhushan Bay with higher eco-exergy but lower specific eco-exergy. Gradient Boosting Machine (GBM) approach was used to explain the non-linear relationships between two indicators and abiotic factors. This analysis revealed water temperature, inorganic nutrients, and total suspended solids greatly contributed to the two indicators that increased. However, pH rise driven by inorganic carbon played an important role in undermining ecosystem health, particularly when pH was higher than 8.2. This implies that climate change with rising CO2 concentrations has the potential to aggravate eutrophication in Taihu Lake where high nutrient loads are maintained. PMID:28220835

Vertical distribution of Fe and Fe(III)-reducing bacteria in the sediments of Lake Donghu, China.

PubMed

Tian, Cuicui; Wang, Chunbo; Tian, Yingying; Wu, Xingqiang; Xiao, Bangding

2015-08-01

In lake sediments, iron (Fe) is the most versatile element, and the redox cycling of Fe has a wide influence on the biogeochemical cycling of organic and inorganic substances. The aim of the present study was to analyze the vertical distribution of Fe and Fe(III)-reducing bacteria (FeRB) in the surface sediment (30 cm) of Lake Donghu, China. At the 3 sites we surveyed, FeRB and Fe(II)-oxidizing bacteria (FeOB) coexisted in anoxic sediments. Geobacter-related FeRB accounted for 5%-31% of the total Bacteria, while Gallionella-related FeOB accounted for only 0.1%-1.3%. A significant correlation between the relative abundance of poorly crystalline Fe and Geobacter spp. suggested that poorly crystalline Fe favored microbial Fe(III) reduction. Poorly crystalline Fe and Geobacter spp. were significantly associated with solid-phase Fe(II) and total inorganic phosphorus levels. Pore water Fe(II) concentrations negatively correlated with NO3(-) at all sites. We concluded that Geobacter spp. were abundant in the sediments of Lake Donghu, and the redox of Fe might participate in the cycling of nitrogen and phosphorus in sediments. These observations provided insight into the roles of microbial Fe cycling in lake sediments.

Vegetation and climate history in arid western China during MIS2: New insights from pollen and grain-size data of the Balikun Lake, eastern Tien Shan

NASA Astrophysics Data System (ADS)

Zhao, Yongtao; An, Cheng-Bang; Mao, Limi; Zhao, Jiaju; Tang, Lingyu; Zhou, Aifeng; Li, Hu; Dong, Weimiao; Duan, Futao; Chen, Fahu

2015-10-01

Marine Isotope Stage (MIS) 2 is mostly a cold period encompassing the Last Glacial Maximum (LGM), but the regional expression of MIS2 in arid areas of China is not well known. In this paper, we use high-resolution lacustrine pollen and grain-size records from Balikun Lake to infer vegetation, lake evolution, and climate in arid western China during MIS2. Our results suggest that: 1) the regional vegetation around Balikun was mainly dominated by desert and/or desert-steppe, and Balikun Lake was relatively shallow and experienced high aeolian input during MIS2; 2) distinctive runoff from mountain glacial meltwater in the eastern parts of the Balikun basin caused a high relative abundance of Artemisia pollen during the LGM (26.5-19.2 cal kyr BP), while simultaneously the desert areas expanded as indicated by the high abundance of desert shrubs (e.g., Elaeagnaceae, Rhamnaceae, Hippophae). This cold and dry LGM climate triggered a substantial lowering of lake level; 3) an extremely cold and dry climate prevailing from 17.0 to 15.2 cal kyr BP, correlated with Heinrich event 1 (H1), would explain the low vegetation cover found then; and 4) the warm and humid Bølling/Allerød interstadial (BA: ca. 15-ca. 13 cal kyr BP) is clearly recorded in the Balikun region by the development of wetland herb communities (e.g., Poaceae, Cyperaceae, Typha), and the lake level rose due to increased runoff. Our results challenge the traditional view of cold and wet climatic conditions and high lake levels in arid western China during the LGM, and we propose that changes in local temperature modulated by July insolation was an indispensable factor in triggering vegetation evolution in the Balikun region during MIS2.

The gut microbiome of hooded cranes (Grus monacha) wintering at Shengjin Lake, China.

PubMed

Zhao, Guanghong; Zhou, Lizhi; Dong, Yuanqiu; Cheng, Yuanyuan; Song, Yunwei

2017-06-01

Gut microbes of animals play critical roles in processes such as digestion and immunity. Therefore, identifying gut microbes will shed light on understanding the annual life of animal species, particularly those that are threatened or endangered. In the present study, we conducted nucleotide sequence analyses of the 16S rRNA genes of gut microbiome of the hooded cranes (Grus monacha) wintering at Shengjin Lake, China, by Illumina high-throughput sequencing technology. We acquired 503,398 high-quality sequences and 785 operational taxonomic units (OTUs) from 15 fecal samples from different cranes, representing 22 phyla that were dominated by Firmicutes, Proteobacteria, and Actinobacteria. A total of 305 genera were identified that were dominated by Clostridium, Lysinibacillus, and Enterobacter. The core gut microbiome comprised 26 genera, including many probiotic species such as Clostridium, Bacillus, Cellulosilyticum, and Cellulomonas that could catabolize cellulose. The findings reported here contribute to our knowledge of the microbiology of hooded cranes and will likely advance efforts to protect waterbirds that inhabit Shengjin Lake Reserve during winter. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Hydroclimate-driven changes in the landscape structure of the terminal lakes and wetlands of the China's Heihe River Basin.

PubMed

Xiao, Shengchun; Xiao, Honglang; Peng, Xiaomei; Song, Xiang

2015-01-01

Changes in the landscape structure of terminal lakes and wetlands along inland rivers in arid areas are determined by the water balance in the river basins under the impacts of climate change and human activities. Studying the evolution of these landscapes and the mechanisms driving these changes is critical to the sustainable development of river basins. The terminal lakes and wetlands along the lower reaches of the Heihe River, an inland river in arid northwestern China, can be grouped into three types: runoff-recharged, groundwater-recharged, and precipitation-recharged. These water-recharge characteristics determine the degree to which the landscape structure of a terminal lake or wetland is impacted by climate change and human activities. An analysis of seven remote-sensing and hydroclimatic data sets for the Heihe River basin during the last 50 years indicates that hydrological changes in the basin caused by regional human activities were the primary drivers of the observed changes in the spatial and temporal landscape-structure patterns of the terminal lakes and wetlands of the Heihe River. In this warm, dry climatic context, the lakes and wetlands gradually evolved toward and maintained a landscape dominated by saline-alkaline lands and grasslands.

Response of freshwater algae to water quality in Qinshan Lake within Taihu Watershed, China

NASA Astrophysics Data System (ADS)

Zhang, Jianying; Ni, Wanmin; Luo, Yang; Jan Stevenson, R.; Qi, Jiaguo

Although frequent algal blooms in Taihu Lake in China have become major environmental problems and have drawn national and international attention, little is understood about the relationship between algal blooms and water quality. The goal of this study was to assess the growth and species responses of freshwater algae to variation in water quality in Qinshan Lake, located in headwaters of the Taihu watershed. Water samples were collected monthly from ten study sites in the Qinshan Lake and were analyzed for species distribution of freshwater algae and physiochemical parameters such as total nitrogen (TN), NH4+-N, NO3--N, total phosphorus (TP), chemical oxygen demand (COD Mn) and Chl-a. The results showed that average TN was 4.47 mg/L, with 92.2% of values greater than the TN standard set by the Chinese Environmental Protection Agency; average TP was 0.051 mg/L, with 37.9% of values above the TP national standard; and average trophic level index (TLI) was 53, the lower end of eutrophic condition. Average Chl-a concentration was 12.83 mg/m 3. Green algae and diatom far outweighed other freshwater algae and were dominant most time of the year, with the highest relative abundances of 96% and 99%, respectively. Blue-green algae, composed mainly toxic strains like Microcystis sp ., Nostoc sp. and Oscillatoria sp., became most dominant in the summer with the maximum relative abundance of 69%. The blue-green algae sank to the lake bottom to overwinter, and then dinoflagellates became the dominant species in the winter, with highest relative abundance of 89%. Analysis indicated that nutrients, especially control of ammonia and co-varying nutrients were the major restrictive factor of population growth of blue-green algae, suggesting that control in nutrient enrichments is the major preventive measure of algal blooms in Qinshan Lake.

Indicator Development for Potential Presence of Schistosomiasis Japonicum's Vector in Lake and Marshland Regions- A Case Study of Poyang Lake, Jiangxi Province, P.R. China

NASA Astrophysics Data System (ADS)

Marie, Tiphanie; Yesou, Herve; Huber, Claire; De Fraipont, Paul; Uribe, Carlos; Lacaux, Jean-Pierre; Lafaye, Murielle; Lai, Xijun; Desnos, Yves-Louis

2013-01-01

Earth observation data and bibliography on environmental parameters were used for mapping Oncomelania hupensis distribution, the Schistosomiasis japonicum’s intermediate host snail, within Poyang Lake (Jiangxi Province, P.R. China). Areas suitable for the development of O. hupensis, the vector of schistosomiasis, were derived from submersion time parameters and vegetation community indicators. ENVISAT time series data acquired from 2000 to 2009 were used for submersion times mapping, and 5 Beijing-1 data acquired during the dry season between 2006 and 2008 were used to map suitable vegetation for vector development. Yearly maps obtained indicate four principally potential endemic areas: the Gan Delta, the bank of the Fu He River, the Dalianzi Hu sector and the Poyang Lake Nature Reserve. Monthly maps from December 2005 to December 2008 show the dynamic of potential O. hupensis presence areas.

Heavy Metal Pollution of Lakes along the Mid-Lower Reaches of the Yangtze River in China: Intensity, Sources and Spatial Patterns

PubMed Central

Zeng, Haiao; Wu, Jinglu

2013-01-01

Lakes in the middle and lower reaches of the Yangtze River form a shallow lake group unique in the World that is becoming increasingly polluted by heavy metals. Previous studies have largely focused on individual lakes, with limited exploration of the regional pattern of heavy metal pollution of the lake group in this area. This paper explores the sources, intensity and spatial patterns of heavy metal pollution of lake sediments. A total of 45 sample lakes were selected and the concentrations of key metal elements in the sediments of each lake were measured. The cluster analysis (CA), principal component analysis (PCA) and Geo-accumulation index (Ig) analysis permitted analysis of the source and pollution intensity of the target lakes. Results suggested a notable spatial variation amongst the sample lakes. Lakes in the upper part of the lower reach of the Yangtze River surrounded by typical urban landscapes were strongly or extremely polluted, with high concentrations of Pb, Zn, Cu and Cd in their sediments. This was attributed to large amount of untreated industrial discharges and municipal sewage produced within the lake catchments. In contrast, the heavy-metal pollution of lakes in the Taihu Delta area was notably lower due to industrial restructuring and implementation of effective environmental protection measures. Lakes along the middle reach of Yangtze River surrounded by agricultural areas were unpolluted to moderately polluted by heavy metals overall. Our results suggested that lakes in the central part of China require immediate attention and efforts should be made to implement management plans to prevent further degradation of water quality in these lakes. PMID:23442559

Impacts of urban sprawl on the area of downtown lakes in a highly developing city on central China

NASA Astrophysics Data System (ADS)

Zhang, W.; Zhang, Y.

2016-12-01

Wuhan city in central China is full of water resources and numerous lakes are located. Downtown lakes have significant ecological value and ornamental value for urban inhabitants in Wuhan. Under the rapid process of urban sprawl, downtown lakes are occupied by impervious areas. This research uses Landsat images to extract land uses from 1991 to 2013 in Wuhan city , and attempts to find out how urban sprawl affects the water body area decline in space. Two largest downtown lakes in Wuhan city, Donghu Lake located in central city and Tangxunhu Lake located in suburbs, are taken as case study area. A direction change index (DCI) is proposed to evaluate the changes of a specific land use in different directions. The results reveal that two downtown lakes are undergoing rapid water body area decline from 1991 to 2013, with decline rate are -0.022 in Donghu watershed and -0.011 in Tangxunhu watershed. 68.26% and 62.50% of the reduced water body is occupied by built-up land in Donghu watershed and Tangxunhu watershed, respectively. According to DCI, the water body reduce is highly correlated with built-up land increase in all direction. Moreover, it is found that in the Donghu watershed the north-west part suffered significant water body area decline, which is close to central city. While in Tangxunhu watershed, the area of water body declined in north-west, south-west and north-east part, and the area obstructed from central city by the lake was suffering less water body area decline. It is concluded that the water body area of downtown lakes are highly affected by the process of urban sprawl, and the lakes in central districts trends to suffer higher descend than that of the downtown lake located in suburbs. Meanwhile, even for the same downtown lake, the area orientating and close to the central city may suffer more rapid decline than the area that does not orientate to the central city.

Bioavailability and preservation of organic phosphorus in freshwater sediments and its role in lake eutrophication

USDA-ARS?s Scientific Manuscript database

Lake eutrophication in China is a serious environmental concern, especially in lakes from the middle and lower reaches of Yangtze River region and Southwestern China Plateau. The dissolution of organic matter can result in release of phosphorus (P) from lake sediments and organic phosphate (Po) itse...

Effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China

PubMed Central

Li, Youzhi; Chen, Xinsheng; Xie, Yonghong; Li, Xu; Li, Feng; Hou, Zhiyong

2014-01-01

This study evaluated the effects of young poplar plantations on understory plant diversity in the Dongting Lake wetlands, China. Poplar plantations resulted in a higher species number and Shannon's diversity. Species compositions were different between areas with poplar and reed populations: a lower ratio of hygrophytes but a higher ratio of mesophytes, and a higher ratio of heliophytes but a lower ratio of neutrophilous or shade plants in poplar areas compared to reed areas. Poplar plantations supported a higher ratio of ligneous plants in the entire Dongting Lake area, but there was no difference in the monitored plots. Unlike reedy areas, poplar plantations had higher light availability but lower soil water content during the growing seasons. These data suggest that young poplar plantations generally increased species richness and plant diversity, but significantly changed species composition due to the reduced soil water and increased light availability. PMID:25208975

Identifying external nutrient reduction requirements and potential in the hypereutrophic Lake Taihu Basin, China.

PubMed

Peng, Jiao-Ting; Zhu, Xiao-Dong; Sun, Xiang; Song, Xiao-Wei

2018-04-01

Reducing external nutrient loads is the first step for controlling eutrophication. Here, we identified external nutrient reduction requirements and potential of strategies for achieving reductions to remediate a eutrophic water body, Lake Taihu, China. A mass balance approach based on the entire lake was used to identify nutrient reduction requirements; an empirical export coefficient approach was introduced to estimate the nutrient reduction potential of the overall program on integrated regulation of Taihu Lake Basin (hereafter referred to as the "Guideline"). Reduction requirements included external total nitrogen (TN) and total phosphorus (TP) loads, which should be reduced by 41-55 and 25-50%, respectively, to prevent nutrient accumulation in Lake Taihu and to meet the planned water quality targets. In 2010, which is the most seriously polluted calendar year during the 2008-2014 period, the nutrient reduction requirements were estimated to be 36,819 tons of N and 2442 tons of P, and the potential nutrient reduction strategies would reduce approximately 25,821 tons of N and 3024 tons of P. Since there is a net N remaining in the reduction requirements, it should be the focus and deserves more attention in identifying external nutrient reduction strategies. Moreover, abatement measures outlined in the Guideline with high P reduction potential required large monetary investments. Achieving TP reduction requirement using the cost-effective strategy costs about 80.24 million USD. The design of nutrient reduction strategies should be enacted according to regional and sectoral differences and the cost-effectiveness of abatement measures.

Carbon dioxide and energy fluxes over a large shallow lake in China

NASA Astrophysics Data System (ADS)

Zhao, Xiaosong

2017-04-01

The turbulent exchange of carbon dioxide and energy between water and atmosphere over lakes differ from those over vegetated surfaces due to high heat capacity of water and different water ecological environment. For a shallow lake, the underlying surface generally changes between water covered and land covered with water level fluctuation, which significantly influences carbon dioxide and energy fluxes. Continuous measurement of the carbon dioxide (CO2), latent (LE) and sensible (H) heat fluxes was made using the eddy covariance method over the Poyang Lake, the largest fresh lake in China, from August 2013 to December 2015. Results indicated that the surface energy budget has a strong seasonal pattern, with peaks in LE and H observed in early August and September. There was 10 days delay between the net radiation and the latent heat flux. More net radiation (Rn) was allocated to the LE rather than H through the year, with monthly mean LE/Rn of 0.65 and H/Rn of 0.11, which caused Bowen ratio was 0.15 in water-covered period, lower than that in land-covered period. The water heat storage experienced shifting from heat storage to heat release, with maximum heat storage in July and maximum heat release in September. The water heat advection was account for 4% to 10% of Rn and peaked in June. The annual evaporation is 875 mm, 893 mm and 1019 mm in 2013 (from August 2013 to July 2014), 2014 and 2015, which was account for approximately 57% of precipitation in the three years. The large lake acted as a CO2 source in inundating period and a CO2 sink in exposure period. The energy fluxes were controlled by environmental factors with timescale dependence. On daily scale, the LE and H were highly correlated with product of wind speed and vapor pressure deficit (UVPD) or wind speed (U) in the water-covered period, and with Rn in the land-covered period. Monthly LE, H and annual H were controlled by Rn, while annual LE was primarily dependent on water depth. Annual CO2 budget

[Soil N/P ratio distribution characteristics of alpine grassland ecosystem in Qinghai-Tibet Plateau].

PubMed

Wang, Jian-Lin; Zhong, Zhi-Ming; Wang, Zhong-Hong; Chen, Bao-Xiong; Zhang, Xian-Zhou; Shen, Zhen-Xi; Hu, Xing-Xiang; Dacizhuoga

2013-12-01

The distribution characteristics of soil N/P ratio in alpine grassland ecosystem of Qinghai-Tibet Plateau were surveyed by field investigation and laboratory analysis. Horizontally, soil N/ P ratio was generally higher in west and lower in east in a manner of staggered patch distribution, with higher N/P ratios mainly centralized in the hinterland of northern part of Tibet Plateau and in the lake basin area of the northern foot of Himalayas. Significant differences in soil N/P ratio were observed among grassland types and natural transects. Vertically, the distribution of N/P ratio along the soil profile from aboveground to underground among different grass types could be categorized into five patterns, including low-high-low-high, low-high-low, low-high, high-low-high-low, and high-low-high. The N/P ratio showed a significant positive correlation with soil bulk density at 0-20 cm depth, soil water content at 20-30 cm depth, contents of soil available K and total nitrogen, respectively. However, it showed significant negative correlation with soil bulk density at 20-30 cm depth, contents of soil available P and total P, respectively.

Responses of landscape pattern of China's two largest freshwater lakes to early dry season after the impoundment of Three-Gorges Dam

NASA Astrophysics Data System (ADS)

Wu, Haipeng; Zeng, Guangming; Liang, Jie; Chen, Jin; Xu, Jijun; Dai, Juan; Sang, Lianhai; Li, Xiaodong; Ye, Shujing

2017-04-01

The effects of hydrologic cycle change (caused by human activity and global climate change) on ecosystems attract the increasing attention around the world. As a result of impounding of the Three Gorges Dam (TGD), climate change and sand mining, the dry season of Poyang Lake and Dongting Lake (China's two largest freshwater lakes) came early after the TGD impoundment. It was the primary cause of the increasing need for sluice/dam construction to store water in the Lakes and attracted increasing attention. In this paper, we compared the landscape pattern between three hydrologic years with early dry season (EY) and three normal hydrologic years (NY) of each lake by remote sensing technology, to reveal the effect of early dry season on landscape pattern. The results showed that early dry season caused expanding of Phalaris to mudflat zone in Poyang Lake, while caused expanding of Carex to Phalaris zone and expanding of Phalaris to mudflat zone in Dongting Lake. In landscape level, there was no significant difference in landscape grain size, landscape grain shape, habitat connectivity and landscape diversity between EY and NY in the two lakes. While in habitat class level, there were significant changes in area of mudflat and Phalaris and grain size of mudflat in Poyang Lake, and in area of Carex, grain size of Phalaris and grain shape of Carex and Phalaris in Dongting Lake. These changes will impact migrating birds of East Asian and migratory fishes of Yangtze River.

Phytoplankton variation and its relationship with the environmental factors in Nansi Lake, China.

PubMed

Tian, Chang; Pei, Haiyan; Hu, Wenrong; Xie, Jun

2013-01-01

Nansi Lake is an important storage lake in the east route of the South-to-North Water Diversion Project in China, about which there has been serious concern regarding the water quality. In this study, the phytoplankton taxonomic composition, abundance, temporal variations, spatial distribution, and diversity were studied based on a monthly sampling campaign from five sampling stations between January 2010 and December 2010. A total of 159 species (8 phyla, 79 genera), including 74 species of Chlorophyta, 36 species of Bacillariophyta, 19 species of Cyanophyta (including 2 water bloom causative species), 21 species of Euglenophyta, 3 species of Cryptophyta, 5 species of Xanthophyta, 2 species of Pyrrophyta, and 2 species of Chrysophyta, were identified. Average phytoplankton diversity index and evenness values were 4.33 and 0.81, respectively, revealing high biodiversity of phytoplankton community. The phytoplankton abundance averaged at 9.51 × 10(6) cells L(-1) and was much higher than previous investigations carried out in 1983-1984. The dominant species were Bacillariophyta, Chlorophyta in winter and spring, and Chlorophyta and Cyanophyta in summer and atutumn. There were 14 predominant species including Chlorella vulgaris, Cyclotella stelligera, Pseudanabaena limnetica, and Chroomonas acuta. Phytoplankton community structure and environmental variable changed substantially over the survey period. Redundancy Analysis was used to analyze the relationship between them. Temperature was considered to be the key factor driving the change in phytoplankton community composition in Nansi Lake during the 2010 study period.

Debris flows resulting from glacial-lake outburst floods in tibet, China

USGS Publications Warehouse

Cui, P.; Dang, C.; Cheng, Z.; Scott, K.

2010-01-01

During the last 70 years of general climatic amelioration, 18 glacial-lake outburst floods (GLOFs) and related debris flows have occurred from 15 moraine-dammed lakes in Tibet, China. Catastrophic loss of life and property has occurred because of the following factors: the large volumes of water discharged, the steep gradients of the U-shaped channels, and the amount and texture of the downstream channel bed and bank material. The peak discharge of each GLOF exceeded 1000 m3/s. These flood discharges transformed to non-cohesive debris flows if the channels contained sufficient loose sediment for entrainment (bulking) and if their gradients were >1%. We focus on this key element, transformation, and suggest that it be included in evaluating future GLOF-related risk, the probability of transformation to debris flow and hyperconcentrated flow. The general, sequential evolution of the flows can be described as from proximal GLOFs, to sedimentladen streamflow, to hyperconcentrated flow, to non-cohesive debris flow (viscous or cohesive debris flow only if sufficient fine sediment is present), and then, distally, back to hyperconcentrated flow and sediment-laden streamflow as sediment is progressively deposited. Most of the Tibet examples transformed only to non-cohesive debris flows. The important lesson for future hazard assessment and mitigation planning is that, as a GLOF entrains (bulks) enough sediment to become a debris flow, the flow volume must increase by at least three times (the "bulking factor"). In fact, the transforming flow waves overrun and mix with downstream streamflow, in addition to adding the entrained sediment (and thus enabling addition of yet more sediment and a bulking factor in excess of three times). To effectively reduce the risk of GLOF debris flows, reducing the level of a potentially dangerous lake with a siphon or excavated spillway or installing gabions in combination with a downstream debris dam are the primary approaches.

Nearly a decade-long repeatable seasonal diversity patterns of bacterioplankton communities in the eutrophic Lake Donghu (Wuhan, China)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Qingyun; Stegen, James C.; Yu, Yuhe

Uncovering which environmental factors have the greatest influence on community diversity patterns and how ecological processes govern community turnover are key questions related to understanding community assembly mechanisms. Although we have good understanding of plant and animal community assembly, the mechanisms regulating diversity patterns of aquatic bacterial communities in lake ecosystems remains poorly understood. Here we present nearly a decade-long time-series study of bacterioplankton communities from the eutrophic Lake Donghu (Wuhan, China) using 16S rRNA gene amplicon sequencing. We found strong repeatable seasonal patterns for the overall community, common (detected in more than 50% samples) and dominant bacterial taxa (relativemore » abundance > 1%). Moreover, community composition tracked the seasonal temperature gradient, indicating that temperature is an important environmental factor controlling observed diversity patterns. Total phosphorus also contributed significantly to the seasonal shifts in bacterioplankton composition. However, any spatial pattern across the main lake areas was overwhelmed by temporal variability in this eutrophic lake system. Phylogenetic analysis further indicated that 75%-82% of community turnover was governed by homogeneous selection, suggesting that the bacterioplankton communities are mainly controlled by niche-based processes. However, dominant niches available within seasons might be occupied by similar combinations of bacterial taxa with modest dispersal rates throughout this lake system. This study gives us important insights into community assembly and seasonal turnover of lake bacterioplankton, it may be also useful to predict temporal patterns of other planktonic communities.« less

[Analysis of vegetation spatial and temporal variations in Qinghai Province based on remote sensing].

PubMed

Wang, Li-wen; Wei, Ya-xing; Niu, Zheng

2008-06-01

1 km MODIS NDVI time series data combining with decision tree classification, supervised classification and unsupervised classification was used to classify land cover type of Qinghai Province into 14 classes. In our classification system, sparse grassland and sparse shrub were emphasized, and their spatial distribution locations were labeled. From digital elevation model (DEM) of Qinghai Province, five elevation belts were achieved, and we utilized geographic information system (GIS) software to analyze vegetation cover variation on different elevation belts. Our research result shows that vegetation cover in Qinghai Province has been improved in recent five years. Vegetation cover area increases from 370047 km2 in 2001 to 374576 km2 in 2006, and vegetation cover rate increases by 0.63%. Among five grade elevation belts, vegetation cover ratio of high mountain belt is the highest (67.92%). The area of middle density grassland in high mountain belt is the largest, of which area is 94 003 km2. Increased area of dense grassland in high mountain belt is the greatest (1280 km2). During five years, the biggest variation is the conversion from sparse grassland to middle density grassland in high mountain belt, of which area is 15931 km2.

Spatio-temporal Distribution and Chemical Speciation of Iron and Manganese in Sediments from Lake Aha, China

NASA Astrophysics Data System (ADS)

Liu, Feng; Hu, Jiwei; Qin, Fanxin; Jiang, Cuihong; Huang, Xianfei; Deng, Jiajun; Li, Cunxiong

2010-11-01

This paper reports an investigation on pollution and potential risk on elements of iron (Fe) and manganese (Mn) in sediments from Lake Aha, which is a drinking-water source for Guiyang City, the capital of Guizhou Province in southwestern China. In the present research, chemical speciation of Fe and Mn in sediments from the lake was studied based on the sequential extraction procedure developed by Tessier et al.. The results obtained from the study are as follows. The average values of total Fe were 47617 mg/kg and 70325 mg/kg in sediments from the lake in summer and winter respectively, and its speciation consisted mainly of residual and Fe-Mn oxides fractions. The amounts of total Fe and the distribution of its speciation in the sediments should be affected by effluents from a large quantity of deserted coal mines in the lake basin in summer and winter. The average values of total Mn were 7996 mg/kg and 1753 mg/kg in summer and winter respectively, and its speciation is primarily comprised of carbonate and Fe-Mn oxides fractions. The amounts of total Mn and its distribution in different fractions in the sediments were believed to be primarily influenced by effluents from those deserted coal mines in summer and by the condition of redox interface in winter.

Environmental characteristics and changes of sediment pore water dissolved organic matter in four Chinese lakes.

PubMed

Mostofa, Khan M G; Li, Wen; Wu, Fengchang; Liu, Cong-Qiang; Liao, Haiqing; Zeng, Li; Xiao, Min

2018-01-01

Sediment pore waters were examined in four Chinese lakes (Bosten, Qinghai, Chenghai and Dianchi) to characterise the sources of dissolved organic matter (DOM) and their microbial changes in the sediment depth profiles. Parallel factor (PARAFAC) modelling on the sample fluorescence spectra confirmed that the pore water DOM was mostly composed of two components with a mixture of both allochthonous and autochthonous fulvic acid-like substances in three lakes, except Lake Dianchi, and protein-like components in Lake Bosten. However, DOM in Lake Dianchi was composed of three components, including a fulvic acid-like, and two unidentified components, which could originate from mixed sources of either sewerage-impacted allochthonous or autochthonous organic matter (OM). Dissolved organic carbon (DOC) concentrations were typically high (583-7410 μM C) and fluctuated and increased vertically in the depth profile. The fluorescence intensity of the fulvic acid-like substance and absorbance at 254 nm increased vertically in the sediment pore waters of three lakes. A significant relationship between DOC and the fluorescence intensity of the fulvic acid-like component in the sediment pore waters of three lakes, except Lake Dianchi, suggested that the fulvic acid-like component could significantly contribute to total DOM and could originate via complex microbial processes in early diagenesis on OM (ca. phytoplankton, terrestrial plant material) in these lakes. Pore water DOM components could therefore be a useful indicator to assess the DOM sources of the lake sediment during sedimentation over the past several decades, which have been heavily affected by ambient terrestrial vegetation and human activities.

An ecological risk assessment of heavy metal contamination in the surface sediments of Bosten Lake, northwest China.

PubMed

Mamat, Zulpiya; Haximu, Sadiguli; Zhang, Zhao Yong; Aji, Rouzi

2016-04-01

Bosten Lake, a typical rump lake in an oasis in northwest China, was chosen to evaluate the distribution, sources, pollution status, and potential ecological risk of heavy metals. Sediment samples were collected from the lake, and results showed that the values of the eight heavy metals all fell within the Second Soil National Standard, while the average and maximum values of the metals were higher than the background values of the study. Multivariate statistical analysis showed that sediment concentrations of Cd, Pb, Hg, and Zn were mainly influenced by man sources. In comparison, Cu, Ni, Cr, and As were primarily natural in origin. Enrichment factor analysis (EF) and the geo-accumulation index evaluation method (I geo) showed that Cd, Hg, and Pb fell under low and partial serious pollution levels, while Zn, As, Cr, Ni, and Cu mainly were characterized under no pollution and low pollution levels. The potential ecological hazards index (RI) showed that among the eight heavy metals, Pb, Hg, and Cd posed the highest potential ecological risk, with potential ecological hazards indices (RI) of 29.06, 27.71, and 21.54 %, respectively. These findings demonstrated that recent economic development in the area of the basin has led to heavy metal accumulation in the surface sediments of the lake.

Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options

PubMed Central

2014-01-01

Objective Echinococcosis is a major parasitic zoonosis of public health importance in western China. In 2004, the Chinese Ministry of Health estimated that 380,000 people had the disease in the region. The Qinghai-Tibet Plateau is highly co-endemic with both alveolar echinococcosis (AE) and cystic echinococcosis (CE). In the past years, the Chinese government has been increasing the financial support to control the diseases in this region. Therefore, it is very important to identify the significant risk factors of the diseases by reviewing studies done in the region in the past decade to help policymakers design appropriate control strategies. Review Selection criteria for which literature to review were firstly defined. Medline, CNKI (China National Knowledge Infrastructure), and Google Scholar were systematically searched for literature published between January 2000 and July 2011. Significant risk factors found by single factor and/or multiple factors analysis were listed, counted, and summarized. Literature was examined to check the comparability of the data; age and sex specific prevalence with same data structures were merged and used for further analysis. A variety of assumed social, economical, behavioral, and ecological risk factors were studied on the Plateau. Those most at risk were Tibetan herdsmen, the old and female in particular. By analyzing merged comparable data, it was found that females had a significant higher prevalence, and a positive linearity relationship existed between echinococcosis prevalence and increasing age. In terms of behavioral risk factors, playing with dogs was mostly correlated with CE and/or AE prevalence. In terms of hygiene, employing ground water as the drinking water source was significantly correlated with CE and AE prevalence. For definitive hosts, dog related factors were most frequently identified with prevalence of CE or/and AE; fox was a potential risk factor for AE prevalence only. Overgrazing and deforestation

Review of risk factors for human echinococcosis prevalence on the Qinghai-Tibet Plateau, China: a prospective for control options.

PubMed

Wang, Qian; Huang, Yan; Huang, Liang; Yu, Wenjie; He, Wei; Zhong, Bo; Li, Wei; Zeng, Xiangman; Vuitton, Dominique A; Giraudoux, Patrick; Craig, Philip S; Wu, Weiping

2014-01-29

Echinococcosis is a major parasitic zoonosis of public health importance in western China. In 2004, the Chinese Ministry of Health estimated that 380,000 people had the disease in the region. The Qinghai-Tibet Plateau is highly co-endemic with both alveolar echinococcosis (AE) and cystic echinococcosis (CE). In the past years, the Chinese government has been increasing the financial support to control the diseases in this region. Therefore, it is very important to identify the significant risk factors of the diseases by reviewing studies done in the region in the past decade to help policymakers design appropriate control strategies. Selection criteria for which literature to review were firstly defined. Medline, CNKI (China National Knowledge Infrastructure), and Google Scholar were systematically searched for literature published between January 2000 and July 2011. Significant risk factors found by single factor and/or multiple factors analysis were listed, counted, and summarized. Literature was examined to check the comparability of the data; age and sex specific prevalence with same data structures were merged and used for further analysis.A variety of assumed social, economical, behavioral, and ecological risk factors were studied on the Plateau. Those most at risk were Tibetan herdsmen, the old and female in particular. By analyzing merged comparable data, it was found that females had a significant higher prevalence, and a positive linearity relationship existed between echinococcosis prevalence and increasing age. In terms of behavioral risk factors, playing with dogs was mostly correlated with CE and/or AE prevalence. In terms of hygiene, employing ground water as the drinking water source was significantly correlated with CE and AE prevalence. For definitive hosts, dog related factors were most frequently identified with prevalence of CE or/and AE; fox was a potential risk factor for AE prevalence only. Overgrazing and deforestation were significant for

[Carbon balance of household production system in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau, China].

PubMed

Wu, Chao Chao; Gao, Xiao Ye; Hou, Fu Jiang

2017-10-01

The transition zone from the Loess Plateau to the Qinghai-Tibet Plateau is one of the regions with most dramatic changes in agricultural production mode and most sensitive response to the carbon balance effect. This paper analyzed the carbon balance of the agriculture system along the altitude gradient in Tongwei, Weiyuan and Xiahe counties. The results showed that with the increase of altitude, the carbon emission, carbon fixation and carbon sink capacity of crops per unit area decreased accordingly, while the average carbon emission, carbon fixation and carbon source capacity of each household in livestock system increased. The integrated crop-livestock production system changed from carbon sink to carbon source. The average carbon emission of each household rose with altitude, but the carbon fixation was the opposite. The change of percentage ofhousehold in the transition zone from the Loess Plateau to the Qinghai-Tibet Plateau with carbon balance could be fitted with Logistic equation. In the crop system of Tongwei, Weiyuan and Xiahe with the altitude increase, carbon emission at the inflection point where the household percentage accounted for 50.0% was 1491, 857 and 376 kg CE·household -1 , and carbon fixation was 6187, 3872 and 778 kg CE·household -1 , respectively. For the livestock system, carbon emission was 2218, 3725 and 49511 kg CE·household -1 , and carbon fixation was 138, 230 and 2706 kg CE·household -1 , respectively. For the integrated crop-livestock system, carbon emission was 3615, 4583 and 49918 kg CE·household -1 , and carbon fixation was 6289, 4113 and 3819 kg CE·household -1 , respectively, which could be the key point for the regulation of regional carbon balance.

Temporal 222Rn distributions to reveal groundwater discharge into desert lakes: Implication of water balance in the Badain Jaran Desert, China

NASA Astrophysics Data System (ADS)

Luo, Xin; Jiao, Jiu Jimmy; Wang, Xu-sheng; Liu, Kun

2016-03-01

How lake systems are maintained and water is balanced in the lake areas in the Badain Jaran Desert (BJD), northeast of China have been debated for about a decade. In this study, continuous 222Rn measurement is used to quantify groundwater discharge into two representative fresh and brine water lakes in the desert using a steady-state mass-balance model. Two empirical equations are used to calculate atmospheric evasion loss crossing the water-air interface of the lakes. Groundwater discharge rates yielded from the radon mass balance model based on the two empirical equations are well correlated and of almost the same values, confirming the validity of the model. The fresh water and brine lakes have a daily averaged groundwater discharge rate of 7.6 ± 1.7 mm d-1 and 6.4 ± 1.8 mm d-1, respectively. The temporal fluctuations of groundwater discharge show similar patterns to those of the lake water level, suggesting that the lakes are recharged from nearby groundwater. Assuming that all the lakes have the same discharge rate as the two studied lakes, total groundwater discharge into all the lakes in the desert is estimated to be 1.59 × 105 m3 d-1. A conceptual model of water balance within a desert lake catchment is proposed to characterize water behaviors within the catchment. This study sheds lights on the water balance in the BJD and is of significance in sustainable regional water resource utilization in such an ecologically fragile area.

Effectiveness of complementary food supplements and dietary counselling on anaemia and stunting in children aged 6-23 months in poor areas of Qinghai Province, China: a controlled interventional study.

PubMed

Zhang, Yanfeng; Wu, Qiong; Wang, Wei; van Velthoven, Michelle Helena; Chang, Suying; Han, Huijun; Xing, Min; Chen, Li; Scherpbier, Robert W

2016-10-31

To assess the effectiveness of dietary counselling and complementary food supplements on anaemia and stunting prevalence in children aged 6-23 months. A controlled intervention study with measurements of height and haemoglobin levels, and cross-sectional surveys in August 2012 (baseline), 2013 (mid-term) and 2014 (end-line). One intervention county and one control county in rural Qinghai Province, China. Complementary food supplements (containing protein, fat, carbohydrate, vitamin A, B 1 , B 2 , B 12 , D 3 , folic acid, iron, zinc and calcium) and complementary feeding counselling were given in the intervention county. Caregivers and their children aged 6-23 months. Effect of the interventions on the prevalence of anaemia (haemoglobin <110 g/L) and stunting (z-score of height-for-age <-2.0) (controlled for differences between the counties), and on infant feeding practices. The surveys were conducted on 1804, 2187 and 2186 children aged 6-23 months in the intervention county in August 2012, 2013 and 2014, respectively, and 804, 680 and 790 children in the control county, respectively. Between the baseline and end-line surveys, anaemia prevalence decreased more in the intervention county than in the control county (71.1% to 47.8% vs 86.3% to 75.3%, respectively; p<0.0001). There was no difference in the decrease in stunting prevalence between the counties (9.7% to 7.1% vs 17.0% to 15.0%; p=0.7954). The proportions of children given iron-rich or iron-fortified food, introduced to (semi-) solid food at 6-8 months, and given food with minimum dietary diversity increased from 43.2% to 88.8% (p<0.0001), 81.4% to 96% (p=0.0470) and 53.0% to 59.8% (p<0.0001), respectively in the intervention county. We found much higher anaemia prevalence in poor rural areas of Qinghai Province compared with the national data. Community-based complementary food supplements combined with dietary counselling can improve feeding practices and reduce anaemia prevalence. Future studies should

Estimates of long-term water total phosphorus (TP) concentrations in three large shallow lakes in the Yangtze River basin, China.

PubMed

Wu, Pan; Qin, Boqiang; Yu, Ge

2016-03-01

The shallow lakes in the eastern China developed on alluvial plains with high-nutrient sediments, and most overflow into the Yangtze River with short hydraulic residence times, whereas they become eutrophic over long time periods. Assuming strong responses to hydrogeological changes in the basin, we attempted to determine the dynamic eutrophication history of these lakes. Although evaluation models for internal total phosphorus (TP) loading are widely used for deep lakes in Europe and North America, the accuracy of these models for shallow lakes that have smaller water volumes controlled by the geometrical morphology and greater basin area of alluvial plains is unknown. To describe the magnitude of changes in velocity of trophic state for the studied shallow lakes, we first evaluated the P retention model in relation to the major forces driving lake morphology, basin climate, and external discharge and then used the model to estimate changes in TP in three large shallow lakes (Taihu, Chao, and Poyang) over 60 years (1950-2009 AD). The observed levels of TP were verified against the relative error of the three lakes (<6.43 %) and Nash-Sutcliffe coefficients (0.67-0.75). The results showed that the predicted TP concentrations largely increased with hydraulic residence time, especially in extreme drought years, with a generally rising trend in trophic status. The simulated trophic state index showed that lakes Taihu and Poyang became eutrophic in the 1990s, whereas Lake Chao became eutrophic in the 1980s; lakes Taihu and Chao ultimately became hypereutrophic in the 2000s. The analysis suggested that the tropic status of the shallow lakes was affected by both the hydroclimate and geological sedimentation of the Yangtze River basin. This work will contribute to the development of an internal P loading model for further evaluating trophic states.

Determining ecoregional numeric nutrient criteria by stressor-response models in Yungui ecoregion lakes, China.

PubMed

Huo, Shouliang; Ma, Chunzi; Xi, Beidou; Tong, Zhonghua; He, Zhuoshi; Su, Jing; Wu, Fengchang

2014-01-01

The importance of developing numeric nutrient criteria has been recognized to protect the designated uses of water bodies from nutrient enrichment that is associated with broadly occurring levels of nitrogen/phosphorus pollution. The identification and estimation of stressor-response models in aquatic ecosystems has been shown to be useful in the determination of nutrient criteria. In this study, three methods based on stressor-response relationships were applied to determine nutrient criteria for Yungui ecoregion lakes with respect to total phosphorus (TP), total nitrogen (TN), and planktonic chlorophyll a (Chl a). Simple linear regression (SLR) models were established to provide an estimate of the relationship between a response variable and a stressor. Multiple linear regressions were used to simultaneously estimate the effect of TP and TN on Chl a. A morphoedaphic index (MEI) was applied to derive nutrient criteria using data from Yungui ecoregion lakes, which were considered as areas with less anthropogenic influences. Nutrient criteria, as determined by these three methods, showed broad agreement for all parameters. The ranges of numeric nutrient criteria for Yungui ecoregion lakes were determined as follows: TP 0.008-0.010 mg/L and TN 0.140-0.178 mg/L. The stressor-response analysis described will be of benefit to support countries in their numeric criteria development programs and to further the goal of reducing nitrogen/phosphorus pollution in China.

Research on the Relationship between Water Diversion and Water Quality of Xuanwu Lake, China.

PubMed

Song, Weiwei; Xu, Qing; Fu, Xingqian; Zhang, Peng; Pang, Yong; Song, Dahao

2018-06-14

Water diversion is often used to improve water quality to reach the standard of China in the short term. However, this large amount of water diversion can not only improve the water quality, but also lead to a decline in the water quality (total phosphorus, total nitrogen) of Xuanwu Lake. Through theoretical analysis, the relationship between water quality and water diversion is established. We also found that the multiplication of the pollutant degradation coefficient ( K ) and the water residence time ( T ) is a constant ( N ), K⋅T=N. The water quality changed better at first, with the increase of inflow discharge, and then became worse, and the optimal water quality inflow discharge is 180,000 m³/day. By constructing two-dimensional hydrodynamic and water quality models, the optimal diversion water plan is calculated. Through model calculations, it can be seen that reducing the inflow discharge makes the water residence time longer (15.3 days changed to 23.8 days). Thereby, increasing the degradation of pollutants, and thus improving water quality. Compared with other wind directions, the southwest wind makes the water quality of Xuanwu Lake the most uniform. The concentration of water quality first became smaller and then became larger, as the wind speed increased, and eventually became constant. Implementing these results for water quality improvement in small and medium lakes will significantly reduce the cost of water diversion.

Water chemistry in the rives of the permafrost regions on the eastern Qinghai-Tibetan Plateau

NASA Astrophysics Data System (ADS)

Wu, X.; Ma, X.; Ye, L.; Liu, G.

2017-12-01

Qinghai-Tibetan is the largest middle-low latitude permafrost areas on the world. There are several large rivers in the plateau, and the changes of the water resources of these rivers are associated with the water resource security of more than 1.35 billion people. Due to the high gradients, these rivers have a tremendous amount of potential energy for electricity output. To promote economic and social development and provide clean energy, hydropower development has taken place on several rivers which originate on the Qinghai-Tibetan Plateau. Since dam construction affect the flow velocity, water temperature, sediments delivery as well as organic matter and nitrogen, it is important to investigate the river chemistry in the head rivers of the reservoirs. We examined the water physio-chemical characteristics in the rivers under the typical vegetation types in the eastern Qinghai-Tibetan Plateau, and further analyzed their relationship to vegetation. The results showed that the total suspended sediment in the rivers were higher within the catchment of alpine steppe, with the lowest dissolved organic carbon content. In contrast, the rivers within the meadow had the highest dissolved organic carbon and lowest total suspension sediment. The dissolved organic carbon significantly positively correlated with the proportions of the meadow and wet meadow in the catchment. The pH, turbidity, and SUVA254 and dissolved organic carbon also correlated with each other. The results suggest that the vegetation type strongly affect the water chemistry in the permafrost regions on the Qinghai-Tibetan Plateau.

Occurrence of antibiotics in water, sediments, aquatic plants, and animals from Baiyangdian Lake in North China.

PubMed

Li, Wenhui; Shi, Yali; Gao, Lihong; Liu, Jiemin; Cai, Yaqi

2012-11-01

This study investigated the presence and distribution of 22 antibiotics, including eight quinolones, nine sulfonamides and five macrolides, in the water, sediments, and biota samples from Baiyangdian Lake, China. A total of 132 samples were collected in 2008 and 2010, and laboratory analyses revealed that antibiotics were widely distributed in the lake. Sulfonamides were the dominant antibiotics in the water (0.86-1563 ng L(-1)), while quinolones were prominent in sediments (65.5-1166 μg kg(-1)) and aquatic plants (8.37-6532 μg kg(-1)). Quinolones (17.8-167 μg kg(-1)) and macrolides [from below detection limit (BDL) to 182 μg kg(-1)] were often found in aquatic animals and birds. Salvinia natans exhibited the highest bioaccumulation capability for quinolones among three species of aquatic plants. Geographical differences of antibiotic concentrations were greatly due to anthropogenic activities. Sewage discharged from Baoding City was likely the main source of antibiotics in the lake. Risk assessment of antibiotics on aquatic organisms suggested that algae and aquatic plants might be at risk in surface water, while animals were likely not at risk. Copyright © 2012 Elsevier Ltd. All rights reserved.

Doing Projects in a Foreign Language — Communications Management, Issues and Strategies

NASA Astrophysics Data System (ADS)

Xian, Deling

The Qinghai Salt Lake Industry Co. Ltd. (QSLIC) smelter project involves a Chinese state-owned client, a Canadian engineering company, their American technology partner, several Chinese design institutes and international vendors. Proper technical communication plays an important role during the development of a project in a foreign language and across cultures. Using the QSLIC project as an example, this paper presents the role of Communications Manager and personal qualifications required, as well as technical communications management, issues and strategies, lessons learnt while doing smelter projects in China and Chinese business culture and etiquette.

A geochemical record of the link between chemical weathering and the East Asian summer monsoon during the late Holocene preserved in lacustrine sediments from Poyang Lake, central China

NASA Astrophysics Data System (ADS)

Huang, Chao; Wei, Gangjian; Li, Wuxian; Liu, Ying

2018-04-01

This paper presents relatively high-resolution geochemical records spanning the past 4000 cal yr BP obtained from the lacustrine sediments of Poyang Lake in central China. The variations in the intensity of the East Asian summer monsoon (EASM) are traced using the K/Na, Ti/Na, Al/K, kaolinite/illite and clay/feldspar ratios, together with the chemical index of alteration (CIA), as indicators of chemical weathering. During the last 4000 years, the proxy records of chemical weathering from Poyang Lake exhibit an overall enhanced trend, consistent with regional hydrological changes in previous independent records. Further comparisons and analyses demonstrate that regional moisture variations in central China is inversely correlated with the EASM intensity, with weak EASM generating high precipitation in central China. Our data reveal three intervals of dramatically dry climatic conditions (i.e., ca. 4000-3200 cal yr BP, ca. 2800-2400 cal yr BP, and ca. 500-200 cal yr BP). A period of weak chemical weathering, related to cold and dry climatic conditions, occurred during the Little Ice Age (LIA), whereas more intense chemical weathering, reflecting warm and humid climatic conditions, was recorded during the Medieval Warm Period (MWP). Besides, an intensification of chemical weathering in Poyang Lake during the late Holocene agrees well with strong ENSO activity, suggesting that moisture variations in central China may be predominantly driven by ENSO variability.

[Construction and evaluation of ecological network in Poyang Lake Eco-economic Zone, China.

PubMed

Chen, Xiao Ping; Chen, Wen Bo

2016-05-01

Large-scale ecological patches play an important role in regional biodiversity conservation. However, with the rapid progress of China's urbanization, human disturbance on the environment is becoming stronger. Large-scale ecological patches will degrade not only in quantity, but also in quality, threatening the connections among them due to isolation and seriously affecting the biodiversity protection. Taking Poyang Lake Eco-economic Zone as a case, this paper established the potential ecological corridors by minimum cost model and GIS technique taking the impacts of landscape types, slope and human disturbance into consideration. Then, based on gravity quantitative model, we analyzed the intensity of ecological interactions between patches, and the potential ecological corridors were divided into two classes for sake of protection. Finally, the important ecological nodes and breaking points were identified, and the structure of the potential ecological network was analyzed. The results showed that forest and cropland were the main landscape types of ecological corridor composition, interaction between ecological patches differed obviously and the structure of the composed regional ecological network was complex with high connectivity and closure. It might provide a scientific basis for the protection of biodiversity and ecological network optimization in Poyang Lake Eco-economic Zone.

Two new species of Protonemura (Plecoptera: Nemouridae) from China, with biogeographical notes on the genus.

PubMed

Li, Weihai; Murányi, Dávid; Yang, Ding

2017-04-26

Two new species of the genus Protonemura (Plecoptera: Nemouridae: Amphinemurinae) are described from China, P. bifurcata sp. n. from a holotype male from Taiwan and P. datongensis sp. n. from males and females collected in Datong County of the high altitude Tibetan Plateau of Qinghai Province, China. The new taxa are compared with related congeners respectively. A new combination, Indonemoura filigera (Kawai) comb. n, is proposed for Protonemura filigera Kawai, 1969. The distribution of Protonemura in the East Palaearctic and the Oriental Region is discussed and mapped.

Multivariate geostatistical analysis and source identification of heavy metals in the sediment of Poyang Lake in China.

PubMed

Dai, Lijun; Wang, Lingqing; Li, Lianfang; Liang, Tao; Zhang, Yongyong; Ma, Chuanxin; Xing, Baoshan

2018-04-15

Heavy metals in lake sediment have become a great concern because their remobilization has frequently occurred under hydrodynamic disturbance in shallow lakes. In this study, heavy metals (Cr, Cu, Cd, Pb, and Zn) concentrations in the surface and core sediments of the largest freshwater lake in China, Poyang Lake, were investigated. Geostatistical prediction maps of heavy metals distribution in the surface sediment were completed as well as further data mining. Based on the prediction maps, the ranges of Cr, Cu, Cd, Pb, and Zn concentrations in the surface sediments of the entire lake were 96.2-175.2, 38.3-127.6, 0.2-2.3, 22.5-77.4, and 72.3-254.4mg/kg, respectively. A self-organizing map (SOM) was applied to find the inner element relation of heavy metals in the sediment cores. K-means clustering of the self-organizing map was also completed to define the Euclidian distance of heavy metals in the sediment cores. The geoaccumulation index (I geo ) for Poyang Lake indicated a varying degree of heavy metal contamination in the surface sediment, especially for Cu. The heavy metal contamination in the sediment profiles had similar pollution levels as those of surface sediment, except for Cd. Correlation matrix mapping and principal component analysis (PCA) were used to support the idea that Cr, Pb, and Zn may be mainly derived from both lithogenic and human activities, such as atmospheric and river inflow transportation, whereas Cu and Cd may be mainly contributed from anthropogenic sources, such as mining activities and fertilizer application. Copyright © 2017 Elsevier B.V. All rights reserved.

Residues, Sources and Potential Biological Risk of Organochlorine Pesticides in Surface Sediments of Qiandao Lake, China.

PubMed

Yang, Huayun; Zhou, Shanshan; Li, Weidong; Liu, Qi; Tu, Yunjie

2015-10-01

Sediment samples were analyzed to comprehensively characterize the concentrations, distribution, possible sources and potential biological risk of organochlorine pesticides in Qiandao Lake, China. Concentrations of sumHCH and sumDDT in sediments ranged from 0.03 to 5.75 ng/g dry weight and not detected to 14.39 ng/g dry weight. The predominant β-HCH and the α-HCH/γ-HCH ratios indicated that the residues of HCHs were derived not only from historical technical HCH use but also from additional usage of lindane. Ratios of o,p'-DDT/p,p'-DDT and DDD/DDE suggested that both dicofol-type DDT and technical DDT applications may be present in most study areas. Additionally, based on two sediment quality guidelines, γ-HCH, o,p'-DDT and p,p'-DDT could be the main organochlorine pesticides species of ecotoxicological concern in Qiandao Lake.

Reconstruction of a Three Hourly 1-km Land Surface Air Temperature Dataset in the Qinghai-Tibet Plateau

NASA Astrophysics Data System (ADS)

Zhou, J.; Ding, L.

2017-12-01

Land surface air temperature (SAT) is an important parameter in the modeling of radiation balance and energy budget of the earth surface. Generally, SAT is measured at ground meteorological stations; then SAT mapping is possible though a spatial interpolation process. The interpolated SAT map relies on the spatial distribution of ground stations, the terrain, and many other factors; thus, it has great uncertainties in regions with complicated terrain. Instead, SAT map can also be obtained through physical modeling of interactions between the land surface and the atmosphere. Such dataset generally has coarse spatial resolution (e.g. coarser than 0.1°) and cannot satisfy the applications at fine scales, e.g. 1 km. This presentation reports the reconstruction of a three hourly 1-km SAT dataset from 2001 to 2015 over the Qinghai-Tibet Plateau. The terrain in the Qinghai-Tibet Plateau, especially in the eastern part, is extremely complicated. Two SAT datasets with good qualities are used in this study. The first one is from the 3h China Meteorological Forcing Dataset with a 0.1° resolution released by the Institute of Tibetan Plateau Research, Chinese Academy of Sciences (Yang et al., 2010); the second one is from the ERA-Interim product with the same temporal resolution and a 0.125° resolution. A statistical approach is developed to downscale the spatial resolution of the derived SAT to 1-km. The elevation and the normalized difference vegetation index (NDVI) are selected as two scaling factors in the downscaling approach. Results demonstrate there is significantly negative correlation between the SAT and elevation in all seasons; there is also significantly negative correlation between the SAT and NDVI in the vegetation growth seasons, while the correlation decreases in the other seasons. Therefore, a temporally dynamic downscaling approach is feasible to enhance the spatial resolution of the SAT. Compared with the SAT at the 0.1° or 0.125°, the reconstructed 1

Effectiveness of complementary food supplements and dietary counselling on anaemia and stunting in children aged 6–23 months in poor areas of Qinghai Province, China: a controlled interventional study

PubMed Central

Zhang, Yanfeng; Wu, Qiong; Wang, Wei; van Velthoven, Michelle Helena; Chang, Suying; Han, Huijun; Xing, Min; Chen, Li; Scherpbier, Robert W.

2016-01-01

Objective To assess the effectiveness of dietary counselling and complementary food supplements on anaemia and stunting prevalence in children aged 6–23 months. Design A controlled intervention study with measurements of height and haemoglobin levels, and cross-sectional surveys in August 2012 (baseline), 2013 (mid-term) and 2014 (end-line). Setting One intervention county and one control county in rural Qinghai Province, China. Intervention Complementary food supplements (containing protein, fat, carbohydrate, vitamin A, B1, B2, B12, D3, folic acid, iron, zinc and calcium) and complementary feeding counselling were given in the intervention county. Participants Caregivers and their children aged 6–23 months. Primary and secondary outcome measures Effect of the interventions on the prevalence of anaemia (haemoglobin <110 g/L) and stunting (z-score of height-for-age <−2.0) (controlled for differences between the counties), and on infant feeding practices. Results The surveys were conducted on 1804, 2187 and 2186 children aged 6–23 months in the intervention county in August 2012, 2013 and 2014, respectively, and 804, 680 and 790 children in the control county, respectively. Between the baseline and end-line surveys, anaemia prevalence decreased more in the intervention county than in the control county (71.1% to 47.8% vs 86.3% to 75.3%, respectively; p<0.0001). There was no difference in the decrease in stunting prevalence between the counties (9.7% to 7.1% vs 17.0% to 15.0%; p=0.7954). The proportions of children given iron-rich or iron-fortified food, introduced to (semi-) solid food at 6–8 months, and given food with minimum dietary diversity increased from 43.2% to 88.8% (p<0.0001), 81.4% to 96% (p=0.0470) and 53.0% to 59.8% (p<0.0001), respectively in the intervention county. Conclusions We found much higher anaemia prevalence in poor rural areas of Qinghai Province compared with the national data. Community-based complementary food supplements

Baektu Mountain, China & North Korea

NASA Image and Video Library

2014-07-14

This image from NASA Terra spacecraft shows Baektu Mountain, an active volcano on the border between North Korea and China. Rising to 2744 m, its summit caldera is filled with a crater lake, Heaven Lake.

Assessment of the Effectiveness of Environmental Dredging in South Lake, China

NASA Astrophysics Data System (ADS)

Wang, Xiao Yu; Feng, Jiang

2007-08-01

Environmental dredging is a primary remedial option for removal of the contaminated material from aquatic environment. Of primary concern in environmental dredging is the effectiveness of the intended sediment removal. A 5-year field monitoring study was conducted to assess the effectiveness of the environmental dredging in South Lake, China. The concentrations of total nitrogen (TN), total phosphors, and heavy metals (Zn, Pb, Cd, Cu, Cr, Ni, Hg, and As) before and after dredging in sediment were determined and compared. Multiple ecological risk indices were employed to assess the contamination of heavy metals before and after dredging. Our results showed that the total phosphorus levels reduced 42% after dredging. Similar changes for Hg, Zn, As Pb, Cd, Cu, Cr, and Ni were observed, with reduction percentages of 97.0, 93.1, 82.6, 63.9, 52.7, 50.1, 32.0, and 23.6, respectively, and the quality of sediment improved based on the criterion of Sediment Quality Guidelines by USEPA and contamination degree values (Cd) decreased significantly (paired t-test, p < 0.05). Unexpectedly, the TN increased 49% after dredging compared to before dredging. Findings from the study demonstrated that the environmental dredging was an effective mechanism for removal of total phosphorus and heavy metals from South Lake. Nevertheless, the dredging was ineffective to remove total nitrogen from sediment. We conclude that the reason for the observed increase in TN after dredging was likely ammonia release from the sediment impairing the dredging effectiveness.

Heavy metal pollution status and ecological risks of sediments under the influence of water transfers in Taihu Lake, China.

PubMed

Liu, Jiajia; Wang, Peifang; Wang, Chao; Qian, Jin; Hou, Jun

2017-01-01

The effects of water transfer projects on water channels and the receiving water involved need to be understood. In this research, the compositions and particle size distributions of surface sediment and the Cd, Cr, Cu, Ni, Pb, and Zn contents and distributions in the sediment along a water transfer route from the Wangyu River to Taihu Lake, China, were studied. The correlative relationship between the grain size trend and heavy metal content distribution suggested that heavy metals in Wangyu River sediment have affected the heavy metal contents of Taihu Lake sediment through silt and clay migrating in the transferred water. Enrichment factors and potential ecological risk values were calculated. Low levels of potential ecological risks are posed at 20 sampling sites in Taihu Lake, but higher-to-serious risks (potential ecological risk values >275) are posed at all Wangyu River sites. Toxicity of heavy metals (Cd, Cu, Zn, and Ni) in the Wangyu River sediments is more serious than those in the Taihu Lake, but is similar to the entrance of Gonghu Bay. Multivariate statistical analyses (Pearson correlation, cluster, and factor analyses) suggested heavy metals in the study area have many sources, and the relationships between particle migration and heavy metal contents indicated transferring water are likely to lead to adverse ecological risks being posed in Taihu Lake.

Assessing Ecotourism from a Multi-stakeholder Perspective: Xingkai Lake National Nature Reserve, China

NASA Astrophysics Data System (ADS)

Su, Ming Ming; Wall, Geoffrey; Ma, Zhong

2014-11-01

Ecotourism development is closely associated with the sustainability of protected natural areas. When facilitated by appropriate management, ecotourism can contribute to conservation and development, as well as the well-being of local communities. As such, ecotourism has been proposed and practiced in different forms in many places, including China. This study assesses ecotourism development at Xingkai Lake National Nature Reserve in Heilongjiang Province, China. Key informant interviews were conducted with representatives from the provincial Forestry Department, the Nature Reserve, and the local community. Observation was undertaken on three site visits and secondary data were collected. The potential for providing quality natural experiences is high and tourism development is occurring rapidly. However, current relationships between people, resources, and tourism have yet to provide mutual benefits necessary for successful ecotourism. The multi-stakeholder management style and the ambiguity of landownership within the nature reserve constitute structural difficulties for ecotourism management and operation. Although participation in ecotourism could provide a livelihood opportunity and interests in involvement in tourism have been identified among the local fishing community, current involvement is limited mainly due to the lack of mechanisms for participation. Therefore, it is recommended that management programs and government policies should be established to provide a platform for community participation in ecotourism. Then, a positive synergistic relationship between tourism, environment, and community could be developed. Planning and policy requirements are discussed for ecotourism development in protected areas in China.

Assessing ecotourism from a multi-stakeholder perspective: Xingkai Lake National Nature Reserve, China.

PubMed

Su, Ming Ming; Wall, Geoffrey; Ma, Zhong

2014-11-01

Ecotourism development is closely associated with the sustainability of protected natural areas. When facilitated by appropriate management, ecotourism can contribute to conservation and development, as well as the well-being of local communities. As such, ecotourism has been proposed and practiced in different forms in many places, including China. This study assesses ecotourism development at Xingkai Lake National Nature Reserve in Heilongjiang Province, China. Key informant interviews were conducted with representatives from the provincial Forestry Department, the Nature Reserve, and the local community. Observation was undertaken on three site visits and secondary data were collected. The potential for providing quality natural experiences is high and tourism development is occurring rapidly. However, current relationships between people, resources, and tourism have yet to provide mutual benefits necessary for successful ecotourism. The multi-stakeholder management style and the ambiguity of landownership within the nature reserve constitute structural difficulties for ecotourism management and operation. Although participation in ecotourism could provide a livelihood opportunity and interests in involvement in tourism have been identified among the local fishing community, current involvement is limited mainly due to the lack of mechanisms for participation. Therefore, it is recommended that management programs and government policies should be established to provide a platform for community participation in ecotourism. Then, a positive synergistic relationship between tourism, environment, and community could be developed. Planning and policy requirements are discussed for ecotourism development in protected areas in China.

Modelling of the estimated contributions of different sub-watersheds and sources to phosphorous export and loading from the Dongting Lake watershed, China.

PubMed

Hou, Ying; Chen, Weiping; Liao, Yuehua; Luo, Yueping

2017-11-03

Considerable growth in the economy and population of the Dongting Lake watershed in Southern China has increased phosphorus loading to the lake and resulted in a growing risk of lake eutrophication. This study aimed to reveal the spatial pattern and sources of phosphorus export and loading from the watershed. We applied an export coefficient model and the Dillon-Rigler model to quantify contributions of different sub-watersheds and sources to the total phosphorus (TP) export and loading in 2010. Together, the upper and lower reaches of the Xiang River watershed and the Dongting Lake Area contributed 60.9% of the TP exported from the entire watershed. Livestock husbandry appeared to be the largest anthropogenic source of TP, contributing more than 50% of the TP exported from each secondary sub-watersheds. The actual TP loading to the lake in 2010 was 62.9% more than the permissible annual TP loading for compliance with the Class III water quality standard for lakes. Three primary sub-watersheds-the Dongting Lake Area, the Xiang River, and the Yuan River watersheds-contributed 91.2% of the total TP loading. As the largest contributor among all sources, livestock husbandry contributed nearly 50% of the TP loading from the Dongting Lake Area and more than 60% from each of the other primary sub-watersheds. This study provides a methodology to identify the key sources and locations of TP export and loading in large lake watersheds. The study can provide a reference for the decision-making for controlling P pollution in the Dongting Lake watershed.

Using dual isotopes to evaluate sources and transformations of nitrate in the West Lake watershed, eastern China.

PubMed

Jin, Zanfang; Qin, Xue; Chen, Lingxiao; Jin, Mantong; Li, Feili

2015-01-01

The West Lake is a World Heritage site in the West Lake watershed in eastern China. In this study, the hydrogeological and dual isotopic approaches were integrated to evaluate the seasonal and spatial variations of nitrate (NO3(-)) in the West Lake watershed, and to characterize NO3(-) sources and transformations. The results revealed that the geochemical facies of the water samples were dominated by Ca(2+)+Na(+)-HCO3(-)+SO4(2)(-) in the surface water and transfer water, Ca(2+)+Na(+)-HCO3(-) and Ca(2+)+Na(+)-SO4(2-) in the groundwater, which most likely reflect natural reactions and anthropogenic inputs. About 13% of the groundwater samples containing NO3(-) exceeded the World Health Organization (WHO) standard of 10 mg N L(-1). NO3(-) was the dominant form of total nitrogen (TN) and was the main surface water contaminant in the West Lake watershed. The δ(15)NNO3 and δ(18)ONO3 values indicated that the dominant NO3(-) sources in surface water were soil nitrogen (soil N) and chemical fertilizers, while the main NO3(-) sources in groundwater were soil N from the forest, chemical fertilizers and manure in the tea garden, domestic sewage from the small, old residential area in the forest as well as urban areas. The distribution of NO3(-) in groundwater was strongly influenced by land use. Results also suggest that there was significant nitrification in surface water and groundwater in the West Lake watershed, and that there were also denitrification processes in groundwater. The annual net fluxes of TN, NO3(-), and NH4(+) into the West Lake were 2.0×10(4), 4.0×10(3), and 1.31×10(4) kg as N, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

Using dual isotopes to evaluate sources and transformations of nitrate in the West Lake watershed, eastern China

NASA Astrophysics Data System (ADS)

Jin, Zanfang; Qin, Xue; Chen, Lingxiao; Jin, Mantong; Li, Feili

2015-06-01

The West Lake is a World Heritage site in the West Lake watershed in eastern China. In this study, the hydrogeological and dual isotopic approaches were integrated to evaluate the seasonal and spatial variations of nitrate (NO3-) in the West Lake watershed, and to characterize NO3- sources and transformations. The results revealed that the geochemical facies of the water samples were dominated by Ca2 + + Na+-HCO3- + SO42- in the surface water and transfer water, Ca2 + + Na+-HCO3- and Ca2 + + Na+-SO42 - in the groundwater, which most likely reflect natural reactions and anthropogenic inputs. About 13% of the groundwater samples containing NO3- exceeded the World Health Organization (WHO) standard of 10 mg N L- 1. NO3- was the dominant form of total nitrogen (TN) and was the main surface water contaminant in the West Lake watershed. The δ15NNO3 and δ18ONO3 values indicated that the dominant NO3- sources in surface water were soil nitrogen (soil N) and chemical fertilizers, while the main NO3- sources in groundwater were soil N from the forest, chemical fertilizers and manure in the tea garden, domestic sewage from the small, old residential area in the forest as well as urban areas. The distribution of NO3- in groundwater was strongly influenced by land use. Results also suggest that there was significant nitrification in surface water and groundwater in the West Lake watershed, and that there were also denitrification processes in groundwater. The annual net fluxes of TN, NO3-, and NH4+ into the West Lake were 2.0 × 104, 4.0 × 103, and 1.31 × 104 kg as N, respectively.

Investigation of avian influenza infections in wild birds, poultry and humans in Eastern Dongting Lake, China.

PubMed

Shi, Jinghong; Gao, Lidong; Zhu, Yun; Chen, Tao; Liu, Yunzhi; Dong, Libo; Liu, Fuqiang; Yang, Hao; Cai, Yahui; Yu, Mingdong; Yao, Yi; Xu, Cuilin; Xiao, Xiangming; Shu, Yuelong

2014-01-01

We investigated avian influenza infections in wild birds, poultry, and humans at Eastern Dongting Lake, China. We analyzed 6,621 environmental samples, including fresh fecal and water samples, from wild birds and domestic ducks that were collected from the Eastern Dongting Lake area from November 2011 to April 2012. We also conducted two cross-sectional serological studies in November 2011 and April 2012, with 1,050 serum samples collected from people exposed to wild birds and/or domestic ducks. Environmental samples were tested for the presence of avian influenza virus (AIV) using quantitative PCR assays and virus isolation techniques. Hemagglutination inhibition assays were used to detect antibodies against AIV H5N1, and microneutralization assays were used to confirm these results. Among the environmental samples from wild birds and domestic ducks, AIV prevalence was 5.19 and 5.32%, respectively. We isolated 39 and 5 AIVs from the fecal samples of wild birds and domestic ducks, respectively. Our analysis indicated 12 subtypes of AIV were present, suggesting that wild birds in the Eastern Dongting Lake area carried a diverse array of AIVs with low pathogenicity. We were unable to detect any antibodies against AIV H5N1 in humans, suggesting that human infection with H5N1 was rare in this region.

Relationships between Heavy Metal Concentrations in Roadside Topsoil and Distance to Road Edge Based on Field Observations in the Qinghai-Tibet Plateau, China

PubMed Central

Yan, Xuedong; Gao, Dan; Zhang, Fan; Zeng, Chen; Xiang, Wang; Zhang, Man

2013-01-01

This study investigated the spatial distribution of copper (Cu), zinc (Zn), cadmium (Cd), lead (Pb), chromium (Cr), cobalt (Co), nickel (Ni) and arsenic (As) in roadside topsoil in the Qinghai-Tibet Plateau and evaluated the potential environmental risks of these roadside heavy metals due to traffic emissions. A total of 120 topsoil samples were collected along five road segments in the Qinghai-Tibet Plateau. The nonlinear regression method was used to formulize the relationship between the metal concentrations in roadside soils and roadside distance. The Hakanson potential ecological risk index method was applied to assess the degrees of heavy metal contaminations. The regression results showed that both of the heavy metals’ concentrations and their ecological risk indices decreased exponentially with the increase of roadside distance. The large R square values of the regression models indicate that the exponential regression method can suitably describe the relationship between heavy metal accumulation and roadside distance. For the entire study region, there was a moderate level of potential ecological risk within a 10 m roadside distance. However, Cd was the only prominent heavy metal which posed potential hazard to the local soil ecosystem. Overall, the rank of risk contribution to the local environments among the eight heavy metals was Cd > As > Ni > Pb > Cu > Co > Zn > Cr. Considering that Cd is a more hazardous heavy metal than other elements for public health, the local government should pay special attention to this traffic-related environmental issue. PMID:23439515

Hydraulic connectivity and evaporation control the water quality and sources of chromophoric dissolved organic matter in Lake Bosten in arid northwest China.

PubMed

Zhou, Lei; Zhou, Yongqiang; Hu, Yang; Cai, Jian; Bai, Chengrong; Shao, Keqiang; Gao, Guang; Zhang, Yunlin; Jeppesen, Erik; Tang, Xiangming

2017-12-01

Lake Bosten is the largest oligosaline lake in arid northwestern China, and water from its tributaries and evaporation control the water balance of the lake. In this study, water quality and chromophoric dissolved organic matter (CDOM) absorption and fluorescence were investigated in different seasons to elucidate how hydraulic connectivity and evaporation may affect the water quality and variability of CDOM in the lake. Mean suspended solids and turbidity were significantly higher in the upstream tributaries than in the lake, the difference being notably more pronounced in the wet than in the dry season. A markedly higher mean first principal component (PC1) score, which was significantly positively related to protein-like components, and a considerably lower fluorescence peak integration ratio - I C :I T , indicative of the terrestrial humic-like CDOM contribution percentage, were observed in the lake than in the upstream tributaries. Correspondingly, notably higher contribution percentages of terrestrial humic-like components were observed in the river mouth areas than in the remaining lake regions. Furthermore, significantly higher mean turbidity, and notably lower mean conductivity and salinity, were recorded in the southwestern Kaidu river mouth than in the remaining lake regions in the wet season. Notably higher mean salinity is recorded in Lake Bosten than in upstream tributaries. Autochthonous protein-like associated amino-acids and also PC1 scores increased significantly with increasing salinity. We conclude that the dynamics of water quality and CDOM composition in remote arid Lake Bosten are strongly driven by evaporation and also the hydraulic connectivity between the upstream tributaries and the downstream lake. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pyrosequencing analysis of free-living and attached bacterial communities in Meiliang Bay, Lake Taihu, a large eutrophic shallow lake in China.

PubMed

Tang, Xiangming; Li, Linlin; Shao, Keqiang; Wang, Boweng; Cai, Xianlei; Zhang, Lei; Chao, Jianying; Gao, Guang

2015-01-01

To elucidate the relationship between particle-attached (PA, ≥ 5.0 μm) and free-living (FL, 0.2-5.0 μm) bacterial communities, samplings were collected seasonally from November 2011 to August 2012 in Meiliang Bay, Lake Taihu, China. We used 454 pyrosequencing of 16S rRNA genes to study bacterial diversity and structure of PA and FL communities. The analysis rendered 37,985 highly qualified reads, subsequently assigned to 1755 operational taxonomic units (97% similarity) for the 8 samples. Although 27 high-level taxonomic groups were obtained, the 3 dominant phyla (Proteobacteria, Actinobacteria, and Bacteroidetes) comprised about 75.9% and 82.4% of the PA and FL fractions, respectively. Overall, we found no significant differences between community types, as indicated by ANOSIM R statistics (R = 0.063, P > 0.05) and the Parsimony test (P = 0.222). Dynamics of bacterial communities were correlated with changes in concentrations of total suspended solids (TSS) and total phosphorus (TP). In summer, a significant taxonomic overlap in the 2 size fractions was observed when Cyanobacteria, a major contributor of TSS and TP, dominated in the water, highlighting the potential rapid exchange between PA and FL bacterial populations in large shallow eutrophic lakes.

The 1988 glacial lake outburst flood in Guangxieco Lake, Tibet, China

NASA Astrophysics Data System (ADS)

Liu, J.-J.; Cheng, Z.-L.; Li, Y.

2014-11-01

The 1988 glacial lake outburst flood (GLOF) in Guangxieco Lake is studied based on geomorphological evidence, interviews with local residents, field surveys in 1990 and 2007, and satellite images from different years. The findings are as follows. (1) The outburst event was caused by two major factors, namely, intense pre-precipitation and persistent high temperatures before the outburst and the low self-stability of the terminal moraine dam as a result of perennial piping. (2) The GLOF, with the peak discharge rate of 1270 m3 s-1, evolved along Midui Valley in the following order: sediment-laden flow, viscous debris flow, non-viscous debris flow, and sediment-laden flood, which was eventually blocked by Palongzangbu River. (3) A comparison between the conditions during the outburst in 1988 and the present conditions suggests a small possibility of a future outburst unless drastic changes occur in landscape and climate. Reconstructing the outburst conditions and the GLOF processes is helpful in assessing a potential outburst in glacier lakes in Tibet.

Significant seasonal variations of microbial community in an acid mine drainage lake in Anhui Province, China.

PubMed

Hao, Chunbo; Wei, Pengfei; Pei, Lixin; Du, Zerui; Zhang, Yi; Lu, Yanchun; Dong, Hailiang

2017-04-01

Acid mine drainage (AMD),characterized by strong acidity and high metal concentrations, generates from the oxidative dissolution of metal sulfides, and acidophiles can accelerate the process significantly. Despite extensive research in microbial diversity and community composition, little is known about seasonal variations of microbial community structure (especially micro eukaryotes) in response to environmental conditions in AMD ecosystem. To this end, AMD samples were collected from Nanshan AMD lake, Anhui Province, China, over a full seasonal cycle from 2013 to 2014, and water chemistry and microbial composition were studied. pH of lake water was stable (∼3.0) across the sampling period, while the concentrations of ions varied dramatically. The highest metal concentrations in the lake were found for Mg and Al, not commonly found Fe. Unexpectedly, ultrahigh concentration of chlorophyll a was measured in the extremely acidic lake, reaching 226.43-280.95 μg/L in winter, even higher than those in most eutrophic freshwater lakes. Both prokaryotic and eukaryotic communities showed a strong seasonal variation. Among the prokaryotes, "Ferrovum", a chemolithotrophic iron-oxidizing bacterium was predominant in most sampling seasons, although it was a minor member prior to September, 2012. Fe 2+ was the initial geochemical factor that drove the variation of the prokaryotic community. The eukaryotic community was simple but varied more drastically than the prokaryotic community. Photoautotrophic algae (primary producers) formed a food web with protozoa or flagellate (top consumers) across all four seasons, and temperature appeared to be responsible for the observed seasonal variation. Ochromonas and Chlamydomonas (responsible for high algal bloom in winter) occurred in autumn/summer and winter/spring seasons, respectively, because of their distinct growth temperatures. The closest phylogenetic relationship between Chlamydomonas species in the lake and those in Arctic

Detritus Quality Controls Macrophyte Decomposition under Different Nutrient Concentrations in a Eutrophic Shallow Lake, North China

PubMed Central

Li, Xia; Cui, Baoshan; Yang, Qichun; Tian, Hanqin; Lan, Yan; Wang, Tingting; Han, Zhen

2012-01-01

Macrophyte decomposition is important for carbon and nutrient cycling in lake ecosystems. Currently, little is known about how this process responds to detritus quality and water nutrient conditions in eutrophic shallow lakes in which incomplete decomposition of detritus accelerates the lake terrestrialization process. In this study, we investigated the effects of detritus quality and water nutrient concentrations on macrophyte decomposition in Lake Baiyangdian, China, by analyzing the decomposition of three major aquatic plants at three sites with different pollution intensities (low, medium, and high pollution sites). Detritus quality refers to detritus nutrient contents as well as C∶N, C∶P, and N∶P mass ratios in this study. Effects of detritus mixtures were tested by combining pairs of representative macrophytes at ratios of 75∶25, 50∶50 and 25∶75 (mass basis). The results indicate that the influence of species types on decomposition was stronger than that of site conditions. Correlation analysis showed that mass losses at the end of the experimental period were significantly controlled by initial detritus chemistry, especially by the initial phosphorus (P) content, carbon to nitrogen (C∶N), and carbon to phosphorus (C∶P) mass ratios in the detritus. The decomposition processes were also influenced by water chemistry. The NO3-N and NH4-N concentrations in the lake water retarded detritus mass loss at the low and high pollution sites, respectively. Net P mineralization in detritus was observed at all sites and detritus P release at the high pollution site was slower than at the other two sites. Nonadditive effects of mixtures tended to be species specific due to the different nutrient contents in each species. Results suggest that the nonadditive effects varied significantly among different sites, indicating that interactions between the detritus quality in species mixtures and site water chemistry may be another driver controlling decomposition

[Community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan salt lake on Qinghai-Tibet Plateau].

PubMed

Shen, Shuo

2017-04-04

I studied the community structure and diversity of culturable moderate halophilic bacteria isolated from Qrhan Salt Lake. I isolated and cultured the moderate halophilic bacteria on different selective media. After the 16S rRNA gene sequences was amplified and measured, I constructed the phylogenic tree, analyzed the community structure and calculated the diversity indexes according to the 16S rRNA gene information. A total of 421 moderate halophilic bacteria were isolated from water and mud samples in Qrhan Salt Lake. The 16S rRNA gene information showed that 4 potential novel species belonged to the family Bacillaceae. Eighty-three model strains belonged to 3 phylurms 6 families 16 genus. Among them, Bacillus sp., Oceanobacillus sp. and Halomonas sp. were dominant species. Diversity analysis showed that the diversity of strains isolated from water sample was higher than that from mud sample, but the dominance degree of strains isolated from mud sample was higher than that from water sample. The genetic diversity of moderate halophilic bacteria isolated from Qrhan Salt Lake was abundant. Also, there were dominant and novel species of culturable moderate halophilic bacteria in this lake.

Moving target feature phenomenology data collection at China Lake

NASA Astrophysics Data System (ADS)

Gross, David C.; Hill, Jeff; Schmitz, James L.

2002-08-01

This paper describes the DARPA Moving Target Feature Phenomenology (MTFP) data collection conducted at the China Lake Naval Weapons Center's Junction Ranch in July 2001. The collection featured both X-band and Ku-band radars positioned on top of Junction Ranch's Parrot Peak. The test included seven targets used in eleven configurations with vehicle motion consisting of circular, straight-line, and 90-degree turning motion. Data was collected at 10-degree and 17-degree depression angles. Key parameters in the collection were polarization, vehicle speed, and road roughness. The collection also included a canonical target positioned at Junction Ranch's tilt-deck turntable. The canonical target included rotating wheels (military truck tire and civilian pick-up truck tire) and a flat plate with variable positioned corner reflectors. The canonical target was also used to simulate a rotating antenna and a vibrating plate. The target vehicles were instrumented with ARDS pods for differential GPS and roll, pitch and yaw measurements. Target motion was also documented using a video camera slaved to the X-band radar antenna and by a video camera operated near the target site.

Increasing heavy metals in the background atmosphere of central North China since the 1980s: Evidence from a 200-year lake sediment record

NASA Astrophysics Data System (ADS)

Wan, Dejun; Song, Lei; Yang, Jinsong; Jin, Zhangdong; Zhan, Changlin; Mao, Xin; Liu, Dongwei; Shao, Yue

2016-08-01

Long-term trends of atmospheric compositions are significant for assessing the influence of human activities on the atmosphere and protecting the atmospheric environment. In this study, based on heavy metal concentrations and Pb isotope ratios in a well-dated sediment core from a remote alpine lake in central North China, anthropogenic fluxes of As, Cd, Sb, and Pb were reconstructed and heavy metal evolutions in the atmosphere were revealed in the last 200 years. The heavy metals in the atmosphere were generally natural origins before 1980 A.D. Since the 1980s they began to increase gradually, but they increased the most in the 1990s resulting from rapid developments of rough and high energy-consuming industries in North China. After entering the 21st century the industries still developed rapidly, but the atmospheric Pb ceased increase and the As and Sb even decreased in the 2000s due to (1) phasing out of leaded gasoline and (2) implementing stricter industrial emission standards in 2000 A.D. in China. However, in the 2000s the atmospheric heavy metals still kept at a relatively high level and even likely began to increase again in the 2010s. Considering the lake relatively remote and seldom affected by local human activities, the results likely reflect heavy metal evolutions in the regional background atmosphere of central North China at the annual/decadal timescale in the last 200 years.

Multimedia fate modeling of perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS) in the shallow lake Chaohu, China.

PubMed

Kong, Xiangzhen; Liu, Wenxiu; He, Wei; Xu, Fuliu; Koelmans, Albert A; Mooij, Wolf M

2018-06-01

Freshwater shallow lake ecosystems provide valuable ecological services to human beings. However, these systems are subject to severe contamination from anthropogenic sources. Per- and polyfluoroalkyl substances (PFASs), including perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS), are among the contaminants that have received substantial attention, primarily due to abundant applications, environment persistence, and potential threats to ecological and human health. Understanding the environmental behavior of these contaminants in shallow freshwater lake environments using a modeling approach is therefore critical. Here, we characterize the fate, transport and transformation of both PFOA and PFOS in the fifth largest freshwater lake in China (Chaohu) during a two-year period (2013-2015) using a fugacity-based multimedia fate model. A reasonable agreement between the measured and modeled concentrations in various compartments confirms the model's reliability. The model successfully quantifies the environmental processes and identifies the major sources and input pathways of PFOA and PFOS to the Chaohu water body. Sensitivity analysis reveals the critical role of nonlinear Freundlich sorption, which contributes to a variable fraction of the model true uncertainty in different compartments (8.1%-93.6%). Through additional model scenario analyses, we further elucidate the importance of nonlinear Freundlich sorption that is essential for the reliable model performance. We also reveal the distinct composition of emission sources for the two contaminants, as the major sources are indirect soil volatilization and direct release from human activities for PFOA and PFOS, respectively. The present study is expected to provide implications for local management of PFASs pollution in Lake Chaohu and to contribute to developing a general model framework for the evaluation of PFASs in shallow lakes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Contamination and Risk Assessment of Heavy Metals in Lake Bed Sediment of a Large Lake Scenic Area in China

PubMed Central

Wan, Li; Xu, Liang; Fu, Yongsheng

2016-01-01

The exposure of heavy metals to lake bed sediment of scenic areas may pose risks on aquatic ecosystems and human health, however very few studies on risk assessment have been reported for scenic areas. Accordingly, this study determined concentration levels, and assessed contamination characteristics and risks, of heavy metals in lake bed sediment of National Scenic Areas Songhuahu (NSAS) in China. The concentrations of Zn, Cr, Pb, Ni, and Cu were determined in 29 bed sediment samples. Results showed that the mean values of Zn, Cr, Pb, Ni, and Cu were 92.69, 90.73, 38.29, 46.77, and 49.44 mg/kg, respectively. Pearson correlation coefficients indicated that organic matter was a major factor influencing distribution of heavy metals. The results for enrichment factors indicated that contamination rates and anthropogenic inputs of single heavy metals decreased in the order Cu > Ni > Pb > Cr > Zn; results of Nemerow integrated pollution index suggested that 72.41% of sampling sites were exposed to low to moderately integrated pollution, and 27.59% of sampling sites were exposed to strongly integrated pollution. According to results for potential ecological risk index, ecological risks of single and all the heavy metals in bed sediment from all the sampling sites were low. Human risks were assessed with hazardous quotients, and the results suggested that exposure of heavy metals to bed sediment posed no or little risk to human health, and the pathway of ingestion significantly contributed to human health risks. PMID:27455296

Lake surface area variation and its responses to climatic change in Yamzhog Yumco Basin, South Tibet during 1970-2010

NASA Astrophysics Data System (ADS)

Zhang, X.; Tian, Y.; Sun, R.

2015-12-01

The research on lake extraction from multi-source and multi-temporal satellite images and the lake size variation can provide reliable method and indispensable information to deepen the understanding about alpine lake changes with the accelerating warming. With field survey experience in the Yamzhog Yumco Basin, South Tibet, the outlines of five lakes (i.e., Yamzhog Yumco, Chen Co, Kongmu Co, Bajiu Co and Puma Yumco) were delineated by the adoption of 42 scenes of satellite images from Landsat, CBERS and HJ from 1970 to 2010, basing on which the responses of alpine lakes to climate change at different timescales were explored. The results are summarized as follows. (1) The seasonal fluctuation of lake surface area was similar with different trend for the five alpine lakes. As for the last 41 years, the annual variation of lake surface area exhibited two kinds of patterns for the five alpine lakes. And the Yamzhog Yumco declined by 9.41%, while the rest four lakes expanded. (2) The responses of alpine lakes to climate change rely on different timescale and water replenishment types. On the one hand, the precipitation change was the predominant driving forces for the seasonal fluctuation and variation trend of lake size, and the rising temperature accounted for the inter-annual lake surface variation. On the other hand, the two kinds of alpine lakes behaviors were well correspondent with the warming temperature over the Qinghai-Tibetan Plateau. The lakes supplied mainly by precipitation shrunk as a result of increased evaporation, and lakes supplied mainly by glacier and snow meltwater, however, expanded because of the remarkable glacier recession. (3) The quantification of hydrological components would hopefully be improved, according to uncertainties analysis, with the adoption of microwave satellite images and higher resolution ones to disclose the interaction mechanism among climate, glacier, and lake in alpine regions.

From Schistosomiasis Vector Habitats Identification to Human Transmission Risk Mapping, in the Poyang Lake Area (Jiangxi Province, PR China)

NASA Astrophysics Data System (ADS)

Marie, T.; Huber, C.; Yesou, H.

2013-01-01

Schistosomiasis (Bilharzias) is the most frequent disease after malaria in the world. This disease hit 200 million people, and threats 600 million people. In China, Schistosomiasis japonicum, a serious communicable parasitic disease, is endemic along the Yangtze River basin, including monsoon lakes. Risky transmission areas are conditioned by the S. japonicum vector’s presence and human activities and presence. On Poyang Lake, marshlands are the principal area of its development. The aim of this work is to answer : Where are areas suitable for vector’s disease development ? Where and what are the human activities the most exposed to disease transmission ? Where are urban areas with the higher level of disease transmission risk ? How data crossing can be useful for identification of areas with the higher transmission risk level ?

Epidemiological Features and Effectiveness of Schistosomiasis Control Programme in Lake and Marshland Region in The People's Republic of China.

PubMed

Zhang, S-Q; Sun, C-S; Wang, M; Lin, D-D; Zhou, X-N; Wang, T-P

2016-01-01

Schistosomiasis is one of neglected tropical diseases in the world. The People's Republic of China has made great achievements in schistosomiasis control through integrated interventions. Although the morbidity and mortality have been reduced to the lowest level in all three endemic regions, namely lake and marshland regions, hilly and mountainous regions and plains with waterway networks regions, the endemic status in lake and marshland region is still that of implementing the interventions in the higher endemicity areas towards elimination of schistosomiasis transmission. This review explores and analyses the endemic characteristics, control measures and its effectiveness in the course of schistosomiasis control programme, in order to provide more theoretical information and experiences for development of appropriate strategies leading to schistosomiasis elimination in the next stage in the country. Copyright © 2016 Elsevier Ltd. All rights reserved.

CO2 diffuse emission from maar lake: An example in Changbai volcanic field, NE China

NASA Astrophysics Data System (ADS)

Sun, Yutao; Guo, Zhengfu; Liu, Jiaqi; Du, Jianguo

2018-01-01

Numerous maars and monogenetic volcanic cones are distributed in northeast China, which are related to westward deep subduction of the Pacific Ocean lithosphere, comprising a significant part of the "Pacific Ring of Fire". It is well known that diffuse CO2 emissions from monogenetic volcanoes, including wet (e.g., maar lake) and dry degassing systems (e.g., soil diffuse emission, fault degassing, etc.), may contribute to budget of globally nature-derived greenhouse gases. However, their relationship between wet (e.g., maar lake) and concomitant dry degassing systems (e.g., soil diffuse emission, fault degassing, etc.) related to monogenetic volcanic field is poorly understood. Yuanchi maar, one of the typical monogenetic volcanic systems, is located on the eastern flank of Tianchi caldera in Changbai volcanic field of northeast China, which displays all of three forms of CO2 degassing including the maar lake, soil micro-seepage and fault degassing. Measurements of efflux of CO2 diffusion from the Yuanchi maar system (YMS) indicate that the average values of CO2 emissions from soil micro-seepage, fault degassing and water-air interface diffusion are 24.3 ± 23.3 g m- 2 d- 1, 39.2 ± 22.4 g m- 2 d- 1 and 2.4 ± 1.1 g m- 2 d- 1, respectively. The minimum output of CO2 diffuse emission from the YMS to the atmosphere is about 176.1 ± 88.3 ton/yr, of which 80.4% results from the dry degassing system. Degassing from the fault contributes to the most of CO2 emissions in all of the three forms of degassing in the YMS. Contributions of mantle, crust, air and organic CO2 to the soil gas are 0.01-0.10%, 10-20%, 32-36% and 48-54%, respectively, which are quantitatively constrained by a He-C isotope coupling calculation model. We propose that CO2 exsolves from the upper mantle melting beneath the Tianchi caldera, which migrates to the crustal magma chamber and further transports to the surface of YMS along the deep fault system. During the transportation processes, the emission

The Dynamics of Microcystis Genotypes and Microcystin Production and Associations with Environmental Factors during Blooms in Lake Chaohu, China

PubMed Central

Yu, Li; Kong, Fanxiang; Zhang, Min; Yang, Zhen; Shi, Xiaoli; Du, Mingyong

2014-01-01

Lake Chaohu, which is a large, shallow, hypertrophic freshwater lake in southeastern China, has been experiencing lake-wide toxic Microcystis blooms in recent decades. To illuminate the relationships between microcystin (MC) production, the genotypic composition of the Microcystis community and environmental factors, water samples and associated environmental data were collected from June to October 2012 within Lake Chaohu. The Microcystis genotypes and MC concentrations were quantified using quantitative real-time PCR (qPCR) and HPLC, respectively. The results showed that the abundances of Microcystis genotypes and MC concentrations varied on spatial and temporal scales. Microcystis exists as a mixed population of toxic and non-toxic genotypes, and the proportion of toxic Microcystis genotypes ranged from 9.43% to 87.98%. Both Pearson correlation and stepwise multiple regressions demonstrated that throughout the entire lake, the abundances of total and toxic Microcystis and MC concentrations showed significant positive correlation with the total phosphorus and water temperature, suggesting that increases in temperature together with the phosphorus concentrations may promote more frequent toxic Microcystis blooms and higher concentrations of MC. Whereas, dissolved inorganic carbon (DIC) was negatively correlated with the abundances of total and toxic Microcystis and MC concentrations, indicating that rising DIC concentrations may suppress toxic Microcystis abundance and reduce the MC concentrations in the future. Therefore, our results highlight the fact that future eutrophication and global climate change can affect the dynamics of toxic Microcystis blooms and hence change the MC levels in freshwater. PMID:25474494

Recent advances on reconstruction of climate and extreme events in China for the past 2000 year

NASA Astrophysics Data System (ADS)

Zheng, Jingyun; Hao, Zhixin; Ge, Quansheng; Liu, Yang

2016-04-01

The study of regional climate changes for past 2000 year could present spatial pattern of climate variation and various historical analogues for the sensitivity and operation of the climate system (e.g., the modulations of internal variability, feedbacks and teleconnections, abrupt changes and regional extreme events, etc.) from inter-annual to centennial scales and provide the knowledge to predict and project climate in the near future. China is distinguished by a prominent monsoon climate in east, continental arid climate in northwest and high land cold climate in Qinghai-Tibetan Plateau located at southwest. The long history of civilization and the variety of climate in China provides an abundant and well-dated documentary records and a wide range of natural archives (e.g., tree-ring, ice core, stalagmite, varved lake sediment, etc.) for high-resolution paleoclimate reconstruction. This paper presented a review of recent advances on reconstruction of climate and extreme events in China for the past 2000 years. In recent 10 years, there were many new high-resolution paleoclimatic reconstructions reported in China, e.g., the annual and decadal resolution series of temperature and precipitation in eastern China derived from historical documents, in western China derived from tree-ring and other natural archives. These new reconstructions provided more proxies and better spatial coverage to understand the characteristics of climate change over China and the uncertainty of regional reconstructions, as well as to reconstruct the high-resolution temperature series and the spatial pattern of precipitation change for whole China in the past millenniums by synthesizing the multi-proxy together. The updated results show that, in China, the warm intervals for the past 2000 years were in AD 1-200, AD 551-760, AD 951-1320, and after AD 1921; as well as the cold intervals were in AD 201-350, AD 441-530, AD 781-950, and AD 1321-1920. The extreme cold winters occurred in periods

Effect of wave-current interactions on sediment resuspension in large shallow Lake Taihu, China.

PubMed

Li, Yiping; Tang, Chunyan; Wang, Jianwei; Acharya, Kumud; Du, Wei; Gao, Xiaomeng; Luo, Liancong; Li, Huiyun; Dai, Shujun; Mercy, Jepkirui; Yu, Zhongbo; Pan, Baozhu

2017-02-01

The disturbance of the water-sediment interface by wind-driven currents and waves plays a critical role in sediment resuspension and internal nutrient release in large, shallow lakes. This study analyzed the effects of the interactions between wind-induced currents an1d waves on the driving mechanism of sediment resuspension in Lake Taihu, the third largest freshwater lake in China, using acoustic and optic techniques to collect long-term, high-frequency, synchronous in situ measurements of wind, currents, waves, and suspended solid concentrations (SSCs). The results suggested that water turbidity started to increase at wind speeds of approximately 4 m/s and significantly increased when wind speeds exceeded 6 m/s. In most cases, wind-induced waves were the main energy source for changes in turbidity. Wave-generated shear stress contributed more than 95% to sediment resuspension and that only in weak wind conditions (<4 m/s) did the lake bottom shear stresses generated by currents and waves contributed equally. The relationship between SSC and bottom shear stress generated by wave was established by fitting the observed results. The processes of sediment dynamics were divided into four stages (A through D) according to three shear-stress thresholds. In stage A, SSC remained stable (about 45 mg/L) and τ w was less than 0.02 N/m 2 . In stage B, the sediment bed was starting to be activated (SSC 45∼60 mg/L) and τ w was in the range of 0.02∼0.07 N/m 2 . In stage C, a medium amount of sediment was suspended (SSC 60∼150 mg/L) and τ w ranged from 0.07 to 0.3 N/m 2 . In stage D, large amount of sediment was suspended (SSC 150∼300 mg/L) and τ w was larger than 0.3 N/m 2 . The findings of this paper reveal the driving mechanism of sediment resuspension, which may further help to evaluate internal nutrient release in large shallow Lake Taihu.

Biodiversity effects on resource use efficiency and community turnover of plankton in Lake Nansihu, China.

PubMed

Tian, Wang; Zhang, Huayong; Zhang, Jian; Zhao, Lei; Miao, Mingsheng; Huang, Hai

2017-04-01

The relationship between biodiversity and ecosystem functioning is a central issue in ecology, especially in aquatic ecosystems due to the ecophysiological characteristics of plankton. Recently, ecologists have obtained conflicting conclusions while analyzing the influence of species diversity on plankton resource use efficiency (RUE) and community turnover. In this study, both phytoplankton and zooplankton communities were investigated seasonally from 2011 to 2013 in Lake Nansihu, a meso-eutrophic and recovering lake in China. The effects of phytoplankton diversity on RUE of phytoplankton (RUE PP ), zooplankton (RUE ZP ), and community turnover were analyzed. Results showed that both phytoplankton species richness and evenness were positively correlated with RUE PP . RUE ZP had a negative relationship with phytoplankton species richness, but a weak unimodal relationship with phytoplankton evenness. Cyanobacteria community had the opposite influence on RUE PP and RUE ZP . Thus, cyanobacteria dominance will benefit RUE PP in eutrophic lakes, but the growth and reproduction of zooplankton are greatly limited. The strong negative relationship between total phosphorus and RUE ZP confirmed these results. Phytoplankton community turnover tended to decrease with increasing phytoplankton evenness, which was consistent with most previous studies. The correlation coefficient between phytoplankton species richness and community turnover was negative, but not significant (p > 0.05). Therefore, phytoplankton community turnover was more sensitive to the variation of evenness than species richness. These results will be helpful in understanding the effects of species diversity on ecosystem functioning in aquatic ecosystems.

Polychlorinated diphenyl ethers (PCDEs) in surface sediments, suspended particulate matter (SPM) and surface water of Chaohu Lake, China.

PubMed

Zhang, Xuesheng; Wang, Tantan; Gao, Lei; Feng, Mingbao; Qin, Li; Shi, Jiaqi; Cheng, Danru

2018-05-31

Polychlorinated diphenyl ethers (PCDEs) are typical halogenated aromatic pollutants that have shown various toxicological effects on organisms. However, the contamination status of PCDEs in the fresh water lakes of China remains poorly researched. In this study, the levels of 15 congeners of PCDEs in the sediments, suspended particulate matter (SPM) and water of Chaohu Lake were determined. The results showed that the ranges of concentrations of total PCDEs (ΣPCDEs) in the sediment, SPM and water were 0.279 ng g -1 dry weight (d.w.)-2.474 ng g -1 d.w., 0.331 ng g -1 d.w.-2.013 ng g -1 d.w. and 0.351 ng L -1 -2.021 ng L -1 , respectively. The most abundant congeners found in sediments, SPM and water were 3,3',4,4'-tetra-CDE, deca-CDE and 2,4,6-tri-CDE, with average contributive ratios of 17.36%, 15.48% and 20.63%, respectively. The medium and higher chlorinated PCDEs (e.g., penta- and deca-CDEs) were the dominant congeners in sediments and SPM. The percentages of lower chlorinated PCDEs (e.g., tri-CDEs) in the water were higher than those in the sediments. The combined input of ΣPCDEs from the eight main tributaries to Chaohu Lake was estimated at 6.94 kg y -1 . Strong linear correlations between the concentrations of ΣPCDEs and organic carbon (OC) contents in three type samples from Chaohu Lake suggested OC could influence the distribution of PCDEs in Chaohu Lake substantially. In addition, the calculated average organic carbon normalized partition coefficients (logK oc ) of 15 PCDEs between water and SPM were in the range of 4.55-5.45 mL g -1 . This study confirmed that Chaohu Lake is contaminated by PCDEs. Copyright © 2018 Elsevier Ltd. All rights reserved.

Origin of the Livelihood Dilemma for Local Fisherman in Poyang Lake Wetland: a Ramsar Site in China

NASA Astrophysics Data System (ADS)

Xie, Dongming; Zhou, Guohong; Zhou, Yangming; Chen, Yayun; Jia, Junsong

2018-01-01

Poyang Lake is one of the first Ramsar sites in China; it has plenty of natural resources that support the survival of local residents. However, local fisherman have encountered a livelihood dilemma, as natural resources have declined, obviously because of the change in the ecological environment and anthropic disturbance. We seek to explain what lead to livelihood dilemma to the local fishermen, so semi-structured interviews, questionnaire surveys, Geographic information system (GIS), Remote sensing (RS), Global position system (GPS), and department data were used to analyze the internal and external factors for these dilemmas. The results explained the external factors including the exhaustion of natural resources, the drying up of wetlands, landscape fragmentation, water contamination, and disturbance through anthropic behavior; the internal factors included the ageing of fishermen, poor cultural quality, conservative ideas, and unreasonable fishing practices. Eco-compensation, industry transformation, and capacity innovation may help to resolve livelihood dilemmas for the local fisherman of the Poyang Lake wetlands.

Distribution characteristic of soil organic carbon fraction in different types of wetland in Hongze Lake of China.

PubMed

Lu, Yan; Xu, Hongwen

2014-01-01

Soil organic carbon fractions included microbial biomass carbon (MBC), dissolved organic carbon (DOC), and labile organic carbon (LOC), which was investigated over a 0-20 cm depth profile in three types of wetland in Hongze Lake of China. Their ecoenvironmental effect and the relationships with soil organic carbon (SOC) were analyzed in present experiment. The results showed that both active and SOC contents were in order reduced by estuarine wetland, flood plain, and out-of-lake wetland. Pearson correlative analysis indicated that MBC and DOC were positively related to SOC. The lowest ratios of MBC and DOC to SOC in the estuarine wetland suggested that the turnover rate of microbial active carbon pool was fairly low in this kind of wetland. Our results showed that estuarine wetland had a strong carbon sink function, which played important role in reducing greenhouse gas emissions; besides, changes of water condition might affect the accumulation and decomposition of organic carbon in the wetland soils.

Distribution Characteristic of Soil Organic Carbon Fraction in Different Types of Wetland in Hongze Lake of China

PubMed Central

Lu, Yan; Xu, Hongwen

2014-01-01

Soil organic carbon fractions included microbial biomass carbon (MBC), dissolved organic carbon (DOC), and labile organic carbon (LOC), which was investigated over a 0–20 cm depth profile in three types of wetland in Hongze Lake of China. Their ecoenvironmental effect and the relationships with soil organic carbon (SOC) were analyzed in present experiment. The results showed that both active and SOC contents were in order reduced by estuarine wetland, flood plain, and out-of-lake wetland. Pearson correlative analysis indicated that MBC and DOC were positively related to SOC. The lowest ratios of MBC and DOC to SOC in the estuarine wetland suggested that the turnover rate of microbial active carbon pool was fairly low in this kind of wetland. Our results showed that estuarine wetland had a strong carbon sink function, which played important role in reducing greenhouse gas emissions; besides, changes of water condition might affect the accumulation and decomposition of organic carbon in the wetland soils. PMID:24971377

Temporal-spatial variations and influencing factors of nitrogen in the shallow groundwater of the nearshore vegetable field of Erhai Lake, China.

PubMed

Chen, Anqiang; Lei, Baokun; Hu, Wanli; Wang, Hongyuan; Zhai, Limei; Mao, Yanting; Fu, Bin; Zhang, Dan

2018-02-01

Nitrogen export from the nearshore vegetable field of Erhai Lake seriously threatens the water quality of Erhai Lake, which is the second largest highland freshwater lake in Yunnan Province, China. Among the nitrogen flows into Erhai Lake, shallow groundwater migration is a major pathway. The nitrogen variation and influencing factors in the shallow groundwater of the nearshore vegetable field of Erhai Lake are not well documented. A 2-year field experiment was conducted to determine the concentrations of nitrogen species in the shallow groundwater and their influencing factors in the nearshore vegetable field of Erhai Lake. The results showed that concentrations of TN, NO 3 - -N, and NO 2 - -N gradually increased with increasing elevation and distance from Erhai Lake, but the opposite was observed for NH 4 + -N in the shallow groundwater. The concentrations of nitrogen species in the rainy season were greater than those in the dry season. NO 3 - -N accounted for more than 79% of total nitrogen in shallow groundwater. Redundancy analysis showed that more than 70% of the temporal and spatial variations of nitrogen concentrations in the shallow groundwater were explained by shallow groundwater depth, and only approximately 10% of variation was explained by the factors of soil porosity, silt clay content of soil, and NH 4 + -N and NO 3 - -N concentrations of soil (p < 0.05). The shallow groundwater depth had more notable effects on nitrogen concentrations in the shallow groundwater than other factors. This result will strongly support the need for further research regarding the management practices for reducing nitrogen concentrations in shallow groundwater.

Bathymetric and sediment facies maps for China Bend and Marcus Flats, Franklin D. Roosevelt Lake, Washington, 2008 and 2009

USGS Publications Warehouse

Weakland, Rhonda J.; Fosness, Ryan L.; Williams, Marshall L.; Barton, Gary J.

2011-01-01

The U.S. Geological Survey (USGS) created bathymetric and sediment facies maps for portions of two reaches of Lake Roosevelt in support of an interdisciplinary study of white sturgeon (Acipenser transmontanus) and their habitat areas within Franklin D. Roosevelt Lake, Washington. In October 2008, scientists from the USGS used a boat-mounted multibeam echo sounder (MBES) to describe bathymetric data to characterize surface relief at China Bend and Marcus Flats, between Northport and Kettle Falls, Washington. In March 2009, an underwater video camera was used to view and record sediment facies that were then characterized by sediment type, grain size, and areas of sand deposition. Smelter slag has been identified as having the characteristics of sand-sized black particles; the two non-invasive surveys attempted to identify areas containing black-colored particulate matter that may be elements and minerals, organic material, or slag. The white sturgeon population in Lake Roosevelt is threatened by the failure of natural recruitment, resulting in a native population that consists primarily of aging fish and that is gradually declining as fish die and are not replaced by nonhatchery reared juvenile fish. These fish spawn and rear in the riverine and upper reservoir reaches where smelter slag is present in the sediment of the river lake bed. Effects of slag on the white sturgeon population in Lake Roosevelt are largely unknown. Two recent studies demonstrated that copper and other metals are mobilized from slag in aqueous environments with concentrations of copper and zinc in bed sediments reaching levels of 10,000 and 30,000 mg/kg due to the presence of smelter slag. Copper was found to be highly toxic to 30-day-old white sturgeon with 96-h LC50 concentrations ranging from 3 to 5 (u or mu)g copper per liter. Older juvenile and adult sturgeons commonly ingest substantial amounts of sediment while foraging. Future study efforts in Lake Roosevelt should include sampling of

Estimation of groundwater discharge and associated chemical fluxes into Poyang Lake, China: approaches using stable isotopes (δD and δ18O) and radon

NASA Astrophysics Data System (ADS)

Liao, Fu; Wang, Guangcai; Shi, Zheming; Cheng, Guoqiang; Kong, Qingmin; Mu, Wenqing; Guo, Liang

2018-05-01

Poyang Lake is the largest freshwater lake in China and is well known for its ecological and economic importance. Understanding the contribution of groundwater to Poyang Lake is important for the lake's protection and management. In this study, stable isotopes (δD and δ18O), 222Rn measurements, and corresponding models (222Rn and 18O mass balance models) were employed to evaluate the groundwater discharge and associated chemical inputs to Poyang Lake. The results showed that the distribution of δ18O in the lake water reflects the groundwater discharge into the lake. The groundwater discharge estimated using the 222Rn mass balance model was in reasonable agreement with the groundwater discharge derived from the 18O mass balance model. The 222Rn mass balance model showed that the groundwater discharge rate was 24.18 ± 6.85 mm/d with a groundwater discharge flux of (2.24 ± 0.63) × 107 m3/d, which accounts for 6.52-11.14% of river-water input in the Poyang Lake area. The groundwater discharge flux estimated using the 18O mass balance model was 3.17 × 107 m3/d, and the average groundwater discharge rate was 26.62 mm/d. The estimated groundwater discharge was used to estimate the associated chemical fluxes. It was found that groundwater-derived heavy metals such as iron and manganese are potential threats to the lake ecological system because of their large inputs from groundwater discharge.

Reconstruction of atmospheric trace metals pollution in Southwest China using sediments from a large and deep alpine lake: Historical trends, sources and sediment focusing.

PubMed

Lin, Qi; Liu, Enfeng; Zhang, Enlou; Nath, Bibhash; Shen, Ji; Yuan, Hezhong; Wang, Rong

2018-02-01

Atmospheric pollution, one of the leading environmental problems in South and East Asia, and its impact on the terrestrial environmental quality remain poorly understood particularly in alpine areas where both historical and present-day mining and smelting operations might leave an imprint. Here, we reconstructed atmospheric trace metals pollution during the past century using core sediments from a large and deep alpine lake in Southwest China. The implication of in lake and/or in watershed sediment focusing in pollution quantification is discussed by analyzing 15 sediment cores. Factor analysis and enrichment factor indicated Cd, Pb and Sb as the typical pollutants. Distinct peaks of Pb and Sb pollution were observed around the 1920s, but little Pb pollution was detected in recent decades, different from other studies in similar regions. Cadmium pollution was observed until the mid-1980s synchronized with Sb. The distinctive variations in atmospheric trace metal pollution process in Southwest China highlight the regional and sub-regional sources of metal pollutants, which should be primarily attributed to non-ferrous metal smelting emissions. Both natural and anthropogenic metals showed wide concentration ranges though exhibited similar temporal trends in the 15 cores. Spatial variations of anthropogenic metals were influenced by the in-watershed pollutants remobilization, whereas, natural metals were regulated by the detrital materials in the sub-basin. In-lake sediment focusing had little influence on the spatial distributions of all metals, different from the traditional sediment focusing pattern observed in small lakes. Anthropogenic Cd accumulation in sediments ranged from 1.5 to 10.1mgm -2 in a specific core with an average of 6.5mgm -2 for the entire lake, highlighting that a reliable whole-lake pollutant budget requires an analysis of multiple cores. Our study suggests that the management of aquatic ecosystem health should take the remobilization of in

Lake Balkhash, Kazakhstan seen from STS-59

NASA Image and Video Library

1994-04-14

STS059-209-081 (9-20 April 1994) --- Lake Balkhash, in eastern Kazakhstan, is some 300 miles long. The lake, frozen in this scene, thawed noticeably during the mission. The shape of the lake is controlled by the delta of the Ili River, which flows from the Tien Shan Mountains in western China across this arid steppe. SRL scientists will use radar data to study the microwave effects of differences in soil moisture, and in freezing or thawing, on the deltaic sediments. Hasselblad camera.

Properties of black carbon and other insoluble light-absorbing particles in seasonal snow of northwestern China

NASA Astrophysics Data System (ADS)

Pu, Wei; Wang, Xin; Wei, Hailun; Zhou, Yue; Shi, Jinsen; Hu, Zhiyuan; Jin, Hongchun; Chen, Quanliang

2017-05-01

A large field campaign was conducted and 284 snow samples were collected at 38 sites in Xinjiang Province and 6 sites in Qinghai Province across northwestern China from January to February 2012. A spectrophotometer combined with chemical analysis was used to measure the insoluble light-absorbing particles (ILAPs) and chemical components in seasonal snow. The results indicate that the cleanest snow was found in northeastern Xinjiang along the border of China, and it presented an estimated black carbon (CBCest) of approximately 5 ng g-1. The dirtiest snow presented a CBCest of approximately 450 ng g-1 near industrial cities in Xinjiang. Overall, the CBCest of most of the snow samples collected in this campaign was in the range of 10-150 ng g-1. Vertical variations in the snowpack ILAPs indicated a probable shift in emission sources with the progression of winter. An analysis of the fractional contributions to absorption implied that organic carbon (OC) dominated the 450 nm absorption in Qinghai, while the contributions from BC and OC were comparable in Xinjiang. Finally, a positive matrix factorization (PMF) model was run to explore the sources of particulate light absorption, and the results indicated an optimal three-factor/source solution that included industrial pollution, biomass burning, and soil dust.

[Differences on geographic distribution of rabies virus lineages in China].

PubMed

Wang, Q; Li, M L; Chen, Y; Wang, B; Tao, X Y; Zhu, W Y

2018-04-10

Objective: To study the lineages of rabies virus and the epidemic characteristics in different provincial populations of China, to provide information for the development of control and prevention measures in each respective provinces. Methods: Full length N and G genes and full-genome of epidemic strains of rabies virus collected in China were downloaded from GenBank and combined with newly sequenced strains by our lab. Each strain was classified under six lineages of China rabies by constructing phylogenetic trees based on the N or G sequences. Numbers of strains and lineages in each province were counted and compared. Results: Six lineages (China Ⅰ-Ⅵ) were prevalent in China, with 4 found in Yunnan and Hunan. In 6 provinces, including Henan and Fujian, 3 lineages were found. In 8 provinces, including Shanghai and Jiangxi, 2 lineages were found Only 1 lineage, were found in Beijing, Tianjin and other 12 provinces. the China Ⅰ, was the dominant one in 25 provinces. In recent years, China Ⅲ had been found in wild animals and spread over livestock in Inner Mongolia and Xinjiang areas. Qinghai and Tibet had been influenced by China Ⅳ, which also been found in wild animals of Inner Mongolia and Heilongjiang. Conclusion: There had been obvious differences in lineages and strain numbers of rabies virus identified in different provinces in China.

Reconstruction of historical lead contamination and sources in Lake Hailing, Eastern China: a Pb isotope study.

PubMed

Zhang, Rui; Guan, Minglei; Shu, Yujie; Shen, Liya; Chen, Xixi; Zhang, Fan; Li, Tiegang; Jiang, Tingchen

2016-05-01

The history records of lead and its stable isotopic ratios were determined in a sediment core to receive anthropogenic impacts on the Lake Hailing in eastern China. The sediment core was dated based on (210)Pb, (137)Cs, and (239+240)Pu. The historical changes of Pb/Al and Pb isotope ratios showed increasing trend upward throughout the core, suggesting changes in energy usage and correlating closely with the experience of a rapid economic and industrial development of the catchment, Linyi City, in eastern China. Based on the mixing end member model of Pb isotope ratios, coal combustion emission dominated anthropogenic Pb sources in the half part of the century contributing 13 to 43 % of total Pb in sediment. Moreover, contributions of chemical and organic fertilizer were 1-13 and 5-14 %, respectively. In contrast, the contribution of leaded gasoline was low than 8 %. The results indicated that historical records of Pb contamination predominantly sourced from coal combustion and chemical and organic fertilizer in the catchment. In addition, an increase of coal combustion source and fertilizers was found throughout the sediment core, whereas the contribution of leaded gasoline had declined after 2000s, which is attributed to the phaseout of leaded gasoline in China.

Snow effects on alpine vegetation in the Qinghai-Tibetan Plateau

USGS Publications Warehouse

Wang, Kun; Zhang, Li; Qiu, Yubao; Ji, Lei; Tian, Feng; Wang, Cuizhen; Wang, Zhiyong

2013-01-01

Understanding the relationships between snow and vegetation is important for interpretation of the responses of alpine ecosystems to climate changes. The Qinghai-Tibetan Plateau is regarded as an ideal area due to its undisturbed features with low population and relatively high snow cover. We used 500 m Moderate Resolution Imaging Spectroradiometer (MODIS) datasets during 2001–2010 to examine the snow–vegetation relationships, specifically, (1) the influence of snow melting date on vegetation green-up date and (2) the effects of snow cover duration on vegetation greenness. The results showed that the alpine vegetation responded strongly to snow phenology (i.e., snow melting date and snow cover duration) over large areas of the Qinghai-Tibetan Plateau. Snow melting date and vegetation green-up date were significantly correlated (p < 0.1) in 39.9% of meadow areas (accounting for 26.2% of vegetated areas) and 36.7% of steppe areas (28.1% of vegetated areas). Vegetation growth was influenced by different seasonal snow cover durations (SCDs) in different regions. Generally, the December–February and March–May SCDs played a significantly role in vegetation growth, both positively and negatively, depending on different water source regions. Snow's positive impact on vegetation was larger than the negative impact.

Examining Land-Use/Land-Cover Change in the Lake Dianchi Watershed of the Yunnan-Guizhou Plateau of Southwest China with Remote Sensing and GIS Techniques: 1974-2008

PubMed Central

Zhao, Yaolong; Zhang, Ke; Fu, Yingchun; Zhang, Hong

2012-01-01

Monitoring land-use/land-cover change (LULCC) and exploring its mechanisms are important processes in the environmental management of a lake watershed. The purpose of this study was to examine the spatiotemporal pattern of LULCC by using multi landscape metrics in the Lake Dianchi watershed, which is located in the Yunnan-Guizhou Plateau of Southwest China. Landsat images from the years 1974, 1988, 1998, and 2008 were analyzed using geographical information system (GIS) techniques. The results reveal that land-use/land-cover has changed greatly in the watershed since 1974. This change in land use structure was embodied in the rapid increase of developed areas with a relative change rate of up to 324.4%. The increase in developed areas mainly occurred in agricultural land, especially near the shores of Lake Dianchi. The spatial pattern and structure of the change was influenced by the urban sprawl of the city of Kunming. The urban sprawl took on the typical expansion mode of cyclic structures and a jigsaw pattern and expanded to the shore of Lake Dianchi. Agricultural land changed little with respect to the structure but changed greatly in the spatial pattern. The landscape in the watershed showed a trend of fragmentation with a complex boundary. The dynamics of land-use/land-cover in the watershed correlate with land-use policies and economic development in China. PMID:23202820

Complete genome sequence of Bacillus velezensis LM2303, a biocontrol strain isolated from the dung of wild yak inhabited Qinghai-Tibet plateau.

PubMed

Chen, Liang

2017-06-10

Bacillus velezensis LM2303 is a biocontrol strain with a broad inhibitory spectrum against plant pathogens, isolated from the dung of wild yak inhabited Qinghai-Tibet plateau, China. Here we present its complete genome sequence, which consists of a single, circular chromosome of 3,989,393bp with a 46.68% G+C content. Genome analysis revealed genes encoding specialized functions for the biosynthesis of antifungal metabolites and antibacterial metabolites, the promotion of plant growth, the alleviation of oxidative stress and nutrient utilization. And the biosynthesis of antimicrobial metabolites in strain LM2303 was confirmed by biochemical analysis, while its plant growth promoting traits were confirmed by inoculation tests. Our results will establish a better foundation for further studies and biocontrol application of B. velezensis LM2303. Copyright © 2017 Elsevier B.V. All rights reserved.

A mathematical model for the transmission of Schistosoma japonicum in consideration of seasonal water level fluctuations of Poyang Lake in Jiangxi, China.

PubMed

Xiang, Jian; Chen, Honggen; Ishikawa, Hirofumi

2013-04-01

Poyang Lake, the largest fresh water lake in China, is the major transmission site of Schistosoma japonicum in China. Epidemics of schistosomiasis japonica have threatened the health of residents and stunted social-economic development there. This article aims at evaluating the effect of various control measures against schistosomiasis: selective mass treatment (ST), targeted mass treatment (TT), mass treatment for animal reservoirs (MT), and health education (HE), on reduction of the prevalence through simulations based on a mathematical model. We proposed a mathematical model, which is a system of ordinary differential equations for the transmission of S. japonicum among humans, bovines, and snails. The model takes into account the seasonal variation of the water level of Poyang Lake that is caused by the backflow of the Yangtze River and inflow from five small rivers, which influences the transmission of S. japonicum. For the purpose of dealing with the age-specific prevalence and intensity of infection, the human population was classified into four age categories in the model. We carried out several simulations resulting from the execution of ST and TT for elementary school children (E Sch), and combinations of ST, MT, and HE. The simulations indicated that all of the control measures only for humans had a trend of revival after interruption, and a combination of ST and MT has a significant effect on reducing human infection. Although TT and HE had a significant effect on the prevalence in the E Sch group, it had little effect on the overall human population. The simulations indicate that measures targeted to bovines such as chemotherapy besides humans will be vital to eliminate the transmission of S. japonicum in the Poyang Lake region. Moreover, it is desirable to improve health education for fishermen and herdsmen. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Estimation of nitrogen and phosphorus flows in livestock production in Dianchi Lake basin, China.

PubMed

Anzai, Hiroki; Wang, Lin; Oishi, Kazato; Irbis, Chagan; Li, Kunzhi; Kumagai, Hajime; Inamura, Tatsuya; Hirooka, Hiroyuki

2016-01-01

We assessed the nitrogen (N) and phosphorus (P) flows in intensified livestock production systems by investigating nutrient budgets and cycling in the basin of Dianchi Lake, one of the most eutrophic lakes in China. We conducted field surveys based on feed samplings and interviews of livestock farmers. The N and P in local and external feeds, animal body retentions, animal products and excretions were calculated at the individual level for dairy cattle, fattening pigs, breeding sows, broilers and laying hens. The N and P flows in the total livestock production system in the area were estimated by multiplying the individual N and P budgets by the number of animals. For the dairy and fattening pig productions, N and P supplied from local crops or by-products accounted for large parts of the inputs. For the other livestock categories, most of the N and P inputs depended on external resources. The N and P outputs through animal manure into the cropland were 287 and 66 kg/ha/year, respectively, which were higher than the N and P inputs into the livestock production systems from the cropland. The N and P loads from manure should be reduced for the establishment of sustainable agricultural production systems. © 2015 Japanese Society of Animal Science.

Bioaccumulation and biomagnification of emerging bisphenol analogues in aquatic organisms from Taihu Lake, China.

PubMed

Wang, Qiang; Chen, Meng; Shan, Guoqiang; Chen, Pengyu; Cui, Shuo; Yi, Shujun; Zhu, Lingyan

2017-11-15

Due to regulations on bisphenol A (BPA) in many countries, a variety of bisphenol analogues are being widely manufactured and applied. However, there is a big knowledge gap on bioaccumulation and biomagnification of these emerging bisphenols in aquatic organisms. The bioaccumulation and magnification of nine bisphenol analogues in aquatic organisms at different trophic levels collected from Taihu Lake, China, were evaluated. The total concentrations of the nine bisphenols in the lake waters were in the range of 49.7-3480ng/L (mean, 389ng/L). BPA, bisphenol AF (BPAF) and bisphenol S (BPS) were the most predominant analogues in the water. The mean natural logarithm bioaccumulation factor (log BAFs) of BPAF, bisphenol C (BPC), bisphenol Z (BPZ) and bisphenol E (BPE) were greater than BPA, and there was a significantly positive correlation between log BAFs of the biphenols and their octanol-water partition coefficients (log K ow ). The trophic magnification factors of BPAF, BPC and BPZ were 2.52, 2.69 and 1.71, respectively, suggesting that they had the potential to biomagnify in the food web. The results of this study call for further investigations on risk assessment of these emerging pollutants in the environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Seasonal changes in the vertical distribution of two types of multicellular magnetotactic prokaryotes in the sediment of Lake Yuehu, China.

PubMed

Liu, Jia; Zhang, Wenyan; Du, Haijian; Leng, Xiaoyun; Li, Jin-Hua; Pan, Hongmiao; Xu, Jianhong; Wu, Long-Fei; Xiao, Tian

2018-04-24

There are two genetically distinct morphological types of multicellular magnetotactic prokaryotes (MMPs) in the intertidal zone of Lake Yuehu (China): ellipsoidal MMPs (eMMPs) and spherical MMPs (sMMPs). We studied the vertical distribution of both types of MMPs in the sediment at Lake Yuehu during 1 year. Both types of MMPs were observed at sediment depths ranging from 1 to 34 cm, depending on the seasons. The eMMPs distributed at depths of 2-34 cm during spring, 1-11 cm during summer, 2-21 cm during autumn and 9-32 cm during winter. The eMMP species Candidatus Magnetananas rongchenensis, with magnetite magnetosomes, dominated at all distribution depths. These results suggested that Ca. M. rongchenensis migrated vertically during four seasons. The vertical profiles of oxidation-reduction potential (ORP) in Lake Yuehu changed seasonally, and these changes coincided with the seasonal distribution of MMPs, suggesting that the ORP affected the vertical distribution of MMPs. In addition, high concentrations of ammonium and silicate were associated with low abundances of MMPs. © 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.

Risk and toxicity assessments of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake, China.

PubMed

Fu, Jie; Hu, Xin; Tao, Xiancong; Yu, Hongxia; Zhang, Xiaowei

2013-11-01

Heavy metal pollution is one of the most serous environmental issues globally. To evaluate the metal pollution in Jiangsu Province of China, the total concentrations of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake were analyzed. Ecological risk of sediments and human health risk of fish consumption were assessed respectively. Furthermore, toxicity of samples on expression of the stress responsive genes was evaluated using microbial live cell-array method. The results showed that the heavy metals concentrations in sediments from the Yangtze River were much higher than those in sediments from the Taihu Lake. However, the fishes from the Taihu Lake had higher concentrations of heavy metals than fishes from the Yangtze River. Ecological risk evaluation showed that the heavy metal contaminants in sediments from the Yangtze River posed higher risk of adverse ecological effects, while sediments from the study areas of Taihu Lake were relatively safe. Health risk assessment suggested that the heavy metals in fishes of both Yangtze River and Taihu Lake might have risk of adverse health effects to human. The toxicity assessment indicated that the heavy metals in these sediments and fishes showed transcriptional effects on the selected 21 stress responsive genes, which were involved in the pathways of DNA damage response, chemical stress, and perturbations of electron transport. Together, this field investigation combined with chemical analysis, risk assessment and toxicity bioassay would provide useful information on the heavy metal pollution in Jiangsu Province. Copyright © 2013 Elsevier Ltd. All rights reserved.

Polycyclic aromatic hydrocarbons (PAHs) in surface sediments of two lakes of the Dongting Lake district in Hunan, China

NASA Astrophysics Data System (ADS)

He, Jiang; Yang, Yajing; Zhang, Lugang; Luo, Yushuang; Liu, Fei; Yang, Pinhong

2018-04-01

In this paper, 18 and 12 surface sediment samples were collected from Datong Lake and Shanpo Lake, respectively, and the 16 USEPA priority Polycyclic aromatic hydrocarbons (PAHs) in these samples were detected. The result indicated that the Σ16PAHs ranged from 206.56 to 1058.98 ng.g-1 with an average concentration of 667.22 ng.g-1 in sediments from Datong Lake, whereas it ranged from 90.62 to 900.70 ng.g-1 with an average concentration of 364.97 ng.g-1 in sediments from Shanpo Lake. The concentrations of individual PAHs in sediments ranged from 5.50 to 85.23 and from 4.39 to 52.74 ng.g-1 in Datong Lake and Shanpo Lake, respectively. According to the indexes such as HMW/LMW, Ant/(Ant+Phe), Flua/(Flua+Pyr), IcdP/(IcdP+BghiP), and BaA/(BaA+Chr), the PAHs in sediments from both lakes are mainly of pyrogenic origin. The total BaP equivalent in the surface sediment samples from Datong Lake and Shanpo Lake is 42.77 and 33.35 ng.g-1, respectively.

Sediment distribution pattern mapped from the combination of objective analysis and geostatistics in the large shallow Taihu Lake, China.

PubMed

Luo, Lian-Cong; Qin, Bo-Qiang; Zhu, Guang-Wei

2004-01-01

Investigation was made into sediment depth at 723 irregularly scattered measurement points which cover all the regions in Taihu Lake, China. The combination of successive correction scheme and geostatistical method was used to get all the values of recent sediment thickness at the 69 x 69 grids in the whole lake. The results showed that there is the significant difference in sediment depth between the eastern area and the western region, and most of the sediments are located in the western shore-line and northern regimes but just a little in the center and eastern parts. The notable exception is the patch between the center and Xishan Island where the maximum sediment depth is more than 4.0 m. This sediment distribution pattern is more than likely related to the current circulation pattern induced by the prevailing wind-forcing in Taihu Lake. The numerical simulation of hydrodynamics can strong support the conclusion. Sediment effects on water quality was also studied and the results showed that the concentrations of TP, TN and SS in the western part are obviously larger than those in the eastern regime, which suggested that more nutrients can be released from thicker sediment areas.

Changes in discharge dynamics under the constraints of local and global changes in the Chao Lake basin (China)

NASA Astrophysics Data System (ADS)

Chu, Y.; Salles, C.; Rodier, C.; Crès, F.-N.; Huang, L.; Tournoud, M.-G.

2012-04-01

Located on the Yangtze basin, the Chao Lake is the fifth largest freshwater lake in China and of great importance in terms of water resources and aquaculture. Its catchment (9130 km2) includes the city of Hefei and large extends of agricultural and rural areas. Fast changes are expected in land uses and agricultural practices for the future, due to the touristic appeal of the Chao Lake shore and the growth of the city of Hefei. Climate changes are also expected in this region, with a high impact on rainfall regime. The consequences of these changes on the sustainability of the water inflows into the lake are a major issue for the economical development of the Chao Lake area even though they are little-known. Our study aims to give tools for estimating such consequences, accounting for uncertainties in scenario data and model parameters. The dynamics of rivers flowing into the Chao Lake is not very well-known, except for the Fengle River. The Fengle catchment (1480 km2) is mainly rural. River discharges are recorded at Taoxi station, upstream its outlet into the lake. 20-year records of daily discharges are available. Nine rain gauges, with daily data, daily temperature and evapotranspiration data are also available. The current dynamics of the Fengle River is characterized in terms of flood frequencies on discharge-duration-frequency curves. The ATHYS freely available hydrological tool (www.athys-soft.org) is used to calibrate and validate a distributed model of the Fengle catchment. Four calibration runs are done on four independent 5-year discharge records. Four different sets of model parameters are discussed. The model is then run for validation. The uncertainties in model predictions are evaluated in terms of errors in the simulated discharges during the validation period, with regards to the 5-year period used for calibration. The model is then applied on scenarios of changes in land uses and climate. Uncertainties in scenarios of changes are estimated

Climate change and human occupations in the Lake Daihai basin, north-central China over the last 4500 years: A geo-archeological perspective

NASA Astrophysics Data System (ADS)

Xu, Lichen; Liu, Yan; Sun, Qianli; Chen, Jing; Cheng, Peng; Chen, Zhongyuan

2017-05-01

High-resolution climate variations since the last 4500 years in the monsoonal-arid transition zone of north-central China were revealed through the integration of proxies from sediment cores in the Lake Daihai basin. Human occupations in the lake basin deduced from archeological findings and historical literatures were then incorporated into the climate sequence to demonstrate the patterns of human responses to the climate changes, and the recent anthropogenic effects. It indicated that: (1) Climate dominated human-environment adaptations prevailed prior to ∼2700 cal yr BP. An amicable climate setting before ∼4100 cal yr BP would facilitate the growth of the Laohushan Culture (LC) in the lake basin, while a pronounced deterioration of water thermal condition after that had led to human exodus and the collapse of the LC. The reduced human activity in the lake basin indicated at ∼3800-3500 cal yr BP and a subsequent cultural blank at ∼3500-2700 cal yr BP, were both in response to the climate and lake level fluctuations during ∼3800-2800 cal yr BP. (2) Transition to a positive human adaptation was seen at ∼2700-1100 cal yr BP, represented by the exploitation of arable land for cultivation and animal husbandry as the lake contracted. (3) An increasing human presence that affected environmental processes became more severe over the last ∼1100 cal yr BP. This was basically due to the ongoing lake shore reclamation for cropping, and more recently heavy metals emissions from fossil fuel combustion and local industries.

Sources, distribution and export coefficient of phosphorus in lowland polders of Lake Taihu Basin, China.

PubMed

Huang, Jiacong; Gao, Junfeng; Jiang, Yong; Yin, Hongbin; Amiri, Bahman Jabbarian

2017-12-01

Identifying phosphorus (P) sources, distribution and export from lowland polders is important for P pollution management, however, is challenging due to the high complexity of hydrological and P transport processes in lowland areas. In this study, the spatial pattern and temporal dynamics of P export coefficient (PEC) from all the 2539 polders in Lake Taihu Basin, China were estimated using a coupled P model for describing P dynamics in a polder system. The estimated amount of P export from polders in Lake Taihu Basin during 2013 was 1916.2 t/yr, with a spatially-averaged PEC of 1.8 kg/ha/yr. PEC had peak values (more than 4.0 kg/ha/yr) in the polders near/within the large cities, and was high during the rice-cropping season. Sensitivity analysis based on the coupled P model revealed that the sensitive factors controlling the PEC varied spatially and changed through time. Precipitation and air temperature were the most sensitive factors controlling PEC. Culvert controlling and fertilization were sensitive factors controlling PEC during some periods. This study demonstrated an estimation of PEC from 2539 polders in Lake Taihu Basin, and an identification of sensitive environmental factors affecting PEC. The investigation of polder P export in a watershed scale is helpful for water managers to learn the distribution of P sources, to identify key P sources, and thus to achieve best management practice in controlling P export from lowland areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characteristics of petroleum contaminants and their distribution in Lake Taihu, China.

PubMed

Guo, Jixiang; Fang, Jia; Cao, Jingjing

2012-08-31

Taihu Lake is a typical plain eutrophic shallow lake. With rapidly economic development of the lake area, the petroleum products and oil wastewater produced in various processes have been inevitably discharged into Taihu Lake. As the major fresh water resource in the economically developed region of Yangtze River Delta, the water quality and environmental condition of Taihu Lake have the direct bearing on the natural environment and sustainable development of economy in this region. For this reason we carried out the study to explore the composition, distribution characteristics and sources of petroleum contaminants in Taihu Lake. The aim of this study was to provide the basis for standard management and pollution control of the Taihu Lake environment. The result showed that water samples from near industrial locations were of relatively higher petroleum contaminants concentrations. The oil pollutants concentrations in different areas of Lake Taihu ranged from 0.106 mg/L to 1.168 mg/L, and the sequence of total contents distribution characteristics of petroleum pollutants from high to low in different regions of Taihu Lake was: "Dapu", "Xiaomeikou", "Zhushan Bay", "Lake center", "Qidu". The results showed that total concentrations of n-alkanes and PAHs ranged from 0.045 to 0.281 mg/L and from 0.011 to 0.034 mg/L respectively. In the same region, the concentrations of hydrocarbon pollutants in the surface and bottom of the lake were higher than that in the middle. This paper reached a conclusion that the petroleum contaminants in Taihu Lake mainly derived from petroleum pollution caused by human activities as indicated by OEP, bimodal distribution, CPI, Pr/Ph ratio, the LMW/HMW ratio and other evaluation indices for sources of n-alkanes and polycyclic aromatic hydrocarbons (PAHs).

Insights into the evolution of pathogenicity of Escherichia coli from genomic analysis of intestinal E. coli of Marmota himalayana in Qinghai-Tibet plateau of China.

PubMed

Lu, Shan; Jin, Dong; Wu, Shusheng; Yang, Jing; Lan, Ruiting; Bai, Xiangning; Liu, Sha; Meng, Qiong; Yuan, Xuejiao; Zhou, Juan; Pu, Ji; Chen, Qiang; Dai, Hang; Hu, Yuanyuan; Xiong, Yanwen; Ye, Changyun; Xu, Jianguo

2016-12-07

Escherichia coli is both of a widespread harmless gut commensal and a versatile pathogen of humans. Domestic animals are a well-known reservoir for pathogenic E. coli. However, studies of E. coli populations from wild animals that have been separated from human activities had been very limited. Here we obtained 580 isolates from intestinal contents of 116 wild Marmot Marmota himalayana from Qinghai-Tibet plateau, China, with five isolates per animal. We selected 125 (hereinafter referred to as strains) from the 580 isolates for genome sequencing, based on unique pulse field gel electrophoresis patterns and at least one isolate per animal. Whole genome sequence analysis revealed that all 125 strains carried at least one and the majority (79.2%) carried multiple virulence genes based on the analysis of 22 selected virulence genes. In particular, the majority of the strains carried virulence genes from different pathovars as potential 'hybrid pathogens'. The alleles of eight virulence genes from the Marmot E. coli were found to have diverged earlier than all known alleles from human and other animal E. coli. Phylogenetic analysis of the 125 Marmot E. coli genomes and 355 genomes selected from 1622 human and other E. coli strains identified two new phylogroups, G and H, both of which diverged earlier than the other phylogroups. Eight of the 12 well-known pathogenic E. coli lineages were found to share a most recent common ancestor with one or more Marmot E. coli strains. Our results suggested that the intestinal E. coli of the Marmots contained a diverse virulence gene pool and is potentially pathogenic to humans. These findings provided a new understanding of the evolutionary origin of pathogenic E. coli.

Lead isotope ratios in six lake sediment cores from Japan Archipelago: Historical record of trans-boundary pollution sources.

PubMed

Hosono, Takahiro; Alvarez, Kelly; Kuwae, Michinobu

2016-07-15

Sediment cores from six lakes situated from north to south on the Japanese Archipelago were collected during 2009-2010 to investigate the hypothesis that deposition of lead (Pb) was coming from East Asia (including China, South Korea and eastern part of Russia). Accumulation rates and ages of the lake sediment were estimated by the (210)Pb constant rate of supply model and (137)Cs inputs to reconstruct the historical trends of Pb accumulation. Cores from four lakes located in the north and central Japan, showed clear evidence of Pb pollution with a change in the (206)Pb/(207)Pb and (208)Pb/(207)Pb ratios in the recent sediment as compared to the deeper sediment. Among the six studied lakes, significant inputs of anthropogenic lead emissions were observed at Lake Mikazuki (north Hokkaido in north Japan), Lake Chokai (north of Honshu), and Lake Mikuriga (central part of Honshu). Pb isotopic comparison of collected core sediment and previously reported data for wet precipitation and aerosols from different Asian regions indicate that, before 1900, Pb accumulated in these three lakes was not affected by trans-boundary sources. Lake Mikazuki started to receive Pb emissions from Russia in early 1900s, and during the last two decades, this lake has been affected by trans-boundary Pb pollution from northern China. Lake Chokai has received Pb pollutant from northern China since early 1900s until 2009, whereas for the Lake Mikuriga the major Pb contaminant was transported from southern China during the past 100years. The results of our study demonstrate that Japan Archipelago has received trans-boundary Pb emissions from different parts of East Asian region depending on location, and the major source region has changed historically. Copyright © 2016 Elsevier B.V. All rights reserved.

Climate change and its impacts on vegetation distribution and net primary productivity of the alpine ecosystem in the Qinghai-Tibetan Plateau.

PubMed

Gao, Qingzhu; Guo, Yaqi; Xu, Hongmei; Ganjurjav, Hasbagen; Li, Yue; Wan, Yunfan; Qin, Xiaobo; Ma, Xin; Liu, Shuo

2016-06-01

Changes in climate have caused impacts on ecosystems on all continents scale, and climate change is also projected to be a stressor on most ecosystems even at the rate of low- to medium-range warming scenarios. Alpine ecosystem in the Qinghai-Tibetan Plateau is vulnerable to climate change. To quantify the climate change impacts on alpine ecosystems, we simulated the vegetation distribution and net primary production in the Qinghai-Tibetan Plateau for three future periods (2020s, 2050s and 2080s) using climate projection for RCPs (Representative Concentration Pathways) RCP4.5 and RCP8.5 scenarios. The modified Lund-Potsdam-Jena Dynamic Global Vegetation Model (LPJ model) was parameter and test to make it applicable to the Qinghai-Tibetan Plateau. Climate projections that were applied to LPJ model in the Qinghai-Tibetan Plateau showed trends toward warmer and wetter conditions. Results based on climate projections indicated changes from 1.3°C to 4.2°C in annual temperature and changes from 2% to 5% in annual precipitation. The main impacts on vegetation distribution was increase in the area of forests and shrubs, decrease in alpine meadows which mainly replaced by shrubs which dominated the eastern plateau, and expanding in alpine steppes to the northwest dominated the western and northern plateau. The NPP was projected to increase by 79% and 134% under the RCP4.5 and RCP8.5. The projected NPP generally increased about 200gC·m(-2)·yr(-1) in most parts of the plateau with a gradual increase from the eastern to the western region of the Qinghai-Tibetan Plateau at the end of this century. Copyright © 2016 Elsevier B.V. All rights reserved.

Examining land-use/land-cover change in the Lake Dianchi watershed of the Yunnan-Guizhou Plateau of Southwest China with remote sensing and GIS techniques: 1974–2008.

PubMed

Zhao, Yaolong; Zhang, Ke; Fu, Yingchun; Zhang, Hong

2012-10-24

Monitoring land-use/land-cover change (LULCC) and exploring its mechanisms are important processes in the environmental management of a lake watershed. The purpose of this study was to examine the spatiotemporal pattern of LULCC by using multi landscape metrics in the Lake Dianchi watershed, which is located in the Yunnan-Guizhou Plateau of Southwest China. Landsat images from the years 1974, 1988, 1998, and 2008 were analyzed using geographical information system (GIS) techniques. The results reveal that land-use/land-cover has changed greatly in the watershed since 1974. This change in land use structure was embodied in the rapid increase of developed areas with a relative change rate of up to 324.4%. The increase in developed areas mainly occurred in agricultural land, especially near the shores of Lake Dianchi. The spatial pattern and structure of the change was influenced by the urban sprawl of the city of Kunming. The urban sprawl took on the typical expansion mode of cyclic structures and a jigsaw pattern and expanded to the shore of Lake Dianchi. Agricultural land changed little with respect to the structure but changed greatly in the spatial pattern. The landscape in the watershed showed a trend of fragmentation with a complex boundary. The dynamics of land-use/land-cover in the watershed correlate with land-use policies and economic development in China.

Highly Pathogenic Avian Influenza A(H5N1) Virus Struck Migratory Birds in China in 2015.

PubMed

Bi, Yuhai; Zhang, Zhenjie; Liu, Wenjun; Yin, Yanbo; Hong, Jianmin; Li, Xiangdong; Wang, Haiming; Wong, Gary; Chen, Jianjun; Li, Yunfeng; Ru, Wendong; Gao, Ruyi; Liu, Di; Liu, Yingxia; Zhou, Boping; Gao, George F; Shi, Weifeng; Lei, Fumin

2015-08-11

Approximately 100 migratory birds, including whooper swans and pochards, were found dead in the Sanmenxia Reservoir Area of China during January 2015. The causative agent behind this outbreak was identified as H5N1 highly pathogenic avian influenza virus (HPAIV). Genetic and phylogenetic analyses revealed that this Sanmenxia H5N1 virus was a novel reassortant, possessing a Clade 2.3.2.1c HA gene and a H9N2-derived PB2 gene. Sanmenxia Clade 2.3.2.1c-like H5N1 viruses possess the closest genetic identity to A/Alberta/01/2014 (H5N1), which recently caused a fatal respiratory infection in Canada with signs of meningoencephalitis, a highly unusual symptom with influenza infections in humans. Furthermore, this virus was shown to be highly pathogenic to both birds and mammals, and demonstrate tropism for the nervous system. Due to the geographical location of Sanmenxia, these novel H5N1 viruses also have the potential to be imported to other regions through the migration of wild birds, similar to the H5N1 outbreak amongst migratory birds in Qinghai Lake during 2005. Therefore, further investigation and monitoring is required to prevent this novel reassortant virus from becoming a new threat to public health.

Dynamics of chromophoric dissolved organic matter influenced by hydrological conditions in a large, shallow, and eutrophic lake in China.

PubMed

Zhou, Yongqiang; Zhang, Yunlin; Shi, Kun; Liu, Xiaohan; Niu, Cheng

2015-09-01

High concentrations of chromophoric dissolved organic matter (CDOM) are terrestrially derived from upstream tributaries to Lake Taihu, China, and are influenced by hydrological conditions of the upstream watershed. To investigate how the dynamics of CDOM in Lake Taihu are influenced by upstream inflow runoff, four sampling cruises, differing in hydrological conditions, were undertaken in the lake and its three major tributaries, rivers Yincun, Dapu, and Changdou. CDOM absorption, fluorescence spectroscopy, chemical oxygen demand (COD), and stable isotope δ(13)C and δ(15)N measurements were conducted to characterize the dynamics of CDOM. The mean absorption coefficient a(350) collected from the three river profiles (5.15 ± 1.92 m(-1)) was significantly higher than that of the lake (2.95 ± 1.88 m(-1)), indicating that the upstream rivers carried a substantial load of CDOM to the lake. This finding was substantiated by the exclusively terrestrial signal exhibited by the level of δ(13)C (-26.23 ± 0.49‰) of CDOM samples collected from the rivers. Mean a(350) and COD in Lake Taihu were significantly higher in the wet season than in the dry season (t test, p < 0.0001), suggesting that the abundance of CDOM in the lake is strongly influenced by hydrological conditions of the watershed. Four components were identified by parallel factor analysis, including two protein-like components (C1 and C2), a terrestrial humic-like component (C3), and a microbial humic-like (C4) component. The contribution percentage of the two humic-like components relative to the summed fluorescence intensity of the four components (C humic) increased significantly from the dry to the wet season. This seasonal difference in contribution further substantiated that an enhanced rainfall followed by an elevated inflow runoff in the lake watershed in the wet season may result in an increase in humic-like substances being discharged into the lake compared to that in the dry

Effects of Different Saline-Alkaline Conditions on the Characteristics of Phytoplankton Communities in the Lakes of Songnen Plain, China

PubMed Central

Zang, Shuying; Fan, Yawen; Ye, Huaxiang

2016-01-01

Many lakes located in the Songnen Plain of China exhibit a high saline-alkaline level. 25 lakes in the Songnen Plain were selected as research objects in this study. Water samples in these lakes were collected from June to August in 2008. Total Dissolved Solids (TDS) and Total Alkalinity (TA) were measured to assess the saline-alkaline level, and partial canonical correspondence analysis (CCA) was conducted as well. The results show that the majority of these lakes in the study area could be categorized into HCO3−-Na+-I type. According to the TDS assessment, of the total 25 lakes, there are 14 for freshwater, 7 for brackish water and 4 for saltwater; and the respective range of TA was from 0.98 to 40.52. The relationship between TA and TDS indicated significant linear relationship (R2 = 0.9292) in the HCO3−-Na+-I type lakes in the Songnen Plain. There was a general trend that cell density, genera richness and taxonomic diversity decreased with the increase of saline-alkaline gradient, whereas a contrary trend was observed for the proportion of dominant species. When the TDS values were above 3×103mg/L and the TA values were above 15mg/L, there was a significant reduction in cell density, genera richness and biodiversity, and their corresponding values were respectively below 10×106 (ind/L), 15 and approximately 2.5. Through the partial canonical correspondence analysis (CCA), 10.7% of the genera variation was explained by pure saline-alkaline variables. Cyclotella meneghiniana, Melosira ambigua and Melosira granulate were found to become the dominant species in most of these lakes, which indicated that there may be rather wide saline-alkaline niches for common dominant species. About one-quarters of the genera which have certain tolerance to salinity and alkalinity preferred to live in the regions with relatively higher saline-alkaline levels in this study. PMID:27749936

Applicability of three-band model for estimating chlorophyll-a concentration in two Asian lakes (Lake Kasumigaura, Japan and Lake Dianchi, China)

NASA Astrophysics Data System (ADS)

Matsushita, B.; Yang, W.; Chen, J.; Fukushima, T.

2009-12-01

Bunkei Matsushita1*, Wei Yang1, 2, Jin Chen2 and Takehiko Fukushima1 1Graduate School of Life and Environmental Sciences, University of Tsukuba 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8572, Japan E-mails: mbunkei@sakura.cc.tsukuba.ac.jp, fukusima@sakura.cc.tsukuba.ac.jp 2 State key laboratory of earth surface processes and resource ecology, Beijing Normal University, Beijing 100875, China E-mails: chenjin@ires.cn, yangwei1022@gmail.com Abstract: The remote sensing of chlorophyll-a in case II water has been far less successful than that in case I water, due mainly to the complex interactions among optically active substances (i.e., phytoplankton, tripton, colored dissolved organic matter, and water) in the former. To address this problem, Gitelson et al. (2008) suggested a three-band model, which can minimize the effects of tripton, colored dissolved organic matter (CDOM), and pure water, and thus promised an accurate estimation of chlorophyll-a. In this study, we used three datasets with different phytoplankton species to test the performance of the three-band model developed by Gitelson et al. The major findings of our study were as follows: (1) the mechanism of the three-band model could work very well for each phytoplankton species (R2>0.84, rRMSE<23%); (2) the slope and intercept of the three-band model strongly depended on variation of phytoplankton species; (3) chlorophyll-specific absorption coefficients at 440 nm (a*ph(440)) could be used to predict the slope and intercept of the three-band model for different species of phytoplankton. Compared with the previous three-band model, the RMSEs of the improved three-band model were reduced from 37.2 mg m-3 to 7.3 mg m-3, and from 34.3 mg m-3 to 15.9 mg m-3, for Lake Kasumigaura, and Lake Dianchi, respectively. Keywords: phytoplankton species, field survey, tank experiment, bio-optical model, case II water

Detours in long-distance migration across the Qinghai-Tibetan Plateau: individual consistency and habitat associations.

PubMed

Liu, Dongping; Zhang, Guogang; Jiang, Hongxing; Lu, Jun

2018-01-01

Migratory birds often follow detours when confronted with ecological barriers, and understanding the extent and the underlying drivers of such detours can provide important insights into the associated cost to the annual energy budget and the migration strategies. The Qinghai-Tibetan Plateau is the most daunting geographical barrier for migratory birds because the partial pressure of oxygen is dramatically reduced and flight costs greatly increase. We analyzed the repeated migration detours and habitat associations of four Pallas's Gulls Larus ichthyaetus across the Qinghai-Tibetan Plateau over 22 migration seasons. Gulls exhibited notable detours, with the maximum distance being more than double that of the expected shortest route, that extended rather than reduced the passage across the plateau. The extent of longitudinal detours significantly increased with latitude, and detours were longer in autumn than in spring. Compared with the expected shortest routes, proximity to water bodies increased along autumn migration routes, but detour-habitat associations were weak along spring migration routes. Thus, habitat availability was likely one, but not the only, factor shaping the extent of detours, and migration routes were determined by different mechanisms between seasons. Significant between-individual variation but high individual consistency in migration timing and routes were revealed in both seasons, indicating a stronger influence of endogenous schedules than local environmental conditions. Gulls may benefit from repeated use of familiar routes and stopover sites, which may be particularly significant in the challenging environment of the Qinghai-Tibetan Plateau.

Monitoring and evaluating the adherence to a complementary food supplement (Ying Yang Bao) among young children in rural Qinghai, China: a mixed methods evaluation study

PubMed Central

Wu, Qiong; Zhang, Yanfeng; Chang, Suying; Wang, Wei; Helena van Velthoven, Michelle; Han, Huijun; Xing, Min; Chen, Li; Du, Xiaozhen; Scherpbier, Robert W

2017-01-01

Background Large investments are currently made in community–based complementary food supplement (Ying Yang Bao, YYB) programs to improve nutrition of young children in rural areas in China. However, there is a lack of knowledge about the experience and challenges of implementing YYB programs in China. We aimed to: 1) monitor distribution of YYB; 2) assess children’s adherence to and acceptability of YYB; and 3) evaluate community–based strategies to improve the program. Methods This mixed methods evaluation study combined data from surveys and focus groups that took place during a controlled interventional evaluation trial. The trial aimed to evaluate the effectiveness of community–based YYB distribution on improving children's health status in rural areas in China. We conducted five cross–sectional surveys with caregivers of children aged 6–23 months (baseline survey (N = 1804) in August 2012 and four follow–up cross–sectional surveys: 1) N = 494 in January 2013; 2) N = 2187 in August 2013; 3) N = 504 in January 2014; and 4) N = 2186 in August 2014) in one rural county in Qinghai Province. We used a two–stage cluster sampling technique to select mothers with eligible children for each survey. Information was collected from caregivers on household characteristics, YYB consumption and acceptability in the surveys. High adherence in each survey was defined as children who consumed at least four YYB sachets during the previous week. A logistic regression model was developed to obtain odds ratios (OR) with 95% confidence intervals of factors associated with high adherence. Also, we conducted 10 focus groups with73 caregivers and health workers involved in the YYB distribution. Content analysis was used to explore qualitative findings, which were used to gain deeper insight into the quantitative results. Results Around 90% of caregivers had ever received YYB and more than 80% of children ever took YYB. Caregivers mainly knew about

Monitoring and evaluating the adherence to a complementary food supplement (Ying Yang Bao) among young children in rural Qinghai, China: a mixed methods evaluation study.

PubMed

Wu, Qiong; Zhang, Yanfeng; Chang, Suying; Wang, Wei; Helena van Velthoven, Michelle; Han, Huijun; Xing, Min; Chen, Li; Du, Xiaozhen; Scherpbier, Robert W

2017-06-01

Large investments are currently made in community-based complementary food supplement (Ying Yang Bao, YYB) programs to improve nutrition of young children in rural areas in China. However, there is a lack of knowledge about the experience and challenges of implementing YYB programs in China. We aimed to: 1) monitor distribution of YYB; 2) assess children's adherence to and acceptability of YYB; and 3) evaluate community-based strategies to improve the program. This mixed methods evaluation study combined data from surveys and focus groups that took place during a controlled interventional evaluation trial. The trial aimed to evaluate the effectiveness of community-based YYB distribution on improving children's health status in rural areas in China. We conducted five cross-sectional surveys with caregivers of children aged 6-23 months (baseline survey (N = 1804) in August 2012 and four follow-up cross-sectional surveys: 1) N = 494 in January 2013; 2) N = 2187 in August 2013; 3) N = 504 in January 2014; and 4) N = 2186 in August 2014) in one rural county in Qinghai Province. We used a two-stage cluster sampling technique to select mothers with eligible children for each survey. Information was collected from caregivers on household characteristics, YYB consumption and acceptability in the surveys. High adherence in each survey was defined as children who consumed at least four YYB sachets during the previous week. A logistic regression model was developed to obtain odds ratios (OR) with 95% confidence intervals of factors associated with high adherence. Also, we conducted 10 focus groups with73 caregivers and health workers involved in the YYB distribution. Content analysis was used to explore qualitative findings, which were used to gain deeper insight into the quantitative results. Around 90% of caregivers had ever received YYB and more than 80% of children ever took YYB. Caregivers mainly knew about YYB through their village doctors. High

Seasonal and interannual dynamics of soil microbial biomass and available nitrogen in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China

NASA Astrophysics Data System (ADS)

Xu, Bo; Wang, Jinniu; Wu, Ning; Wu, Yan; Shi, Fusun

2018-01-01

Soil microbial activity varies seasonally in frozen alpine soils during cold seasons and plays a crucial role in available N pool accumulation in soil. The intra- and interannual patterns of microbial and nutrient dynamics reflect the influences of changing weather factors, and thus provide important insights into the biogeochemical cycles and ecological functions of ecosystems. We documented the seasonal and interannual dynamics of soil microbial and available N in an alpine meadow in the eastern part of Qinghai-Tibet Plateau, China, between April 2011 and October 2013. Soil was collected in the middle of each month and analyzed for water content, microbial biomass C (MBC) and N (MBN), dissolved organic C and N, and inorganic N. Soil microbial community composition was measured by the dilution-plate method. Fungi and actinomycetes dominated the microbial community during the nongrowing seasons, and the proportion of bacteria increased considerably during the early growing seasons. Trends of consistently increasing MBC and available N pools were observed during the nongrowing seasons. MBC sharply declined during soil thaw and was accompanied by a peak in available N pool. Induced by changes in soil temperatures, significant shifts in the structures and functions of microbial communities were observed during the winter-spring transition and largely contributed to microbial reduction. The divergent seasonal dynamics of different N forms showed a complementary nutrient supply pattern during the growing season. Similarities between the interannual dynamics of microbial biomass and available N pools were observed, and soil temperature and water conditions were the primary environmental factors driving interannual fluctuations. Owing to the changes in climate, seasonal soil microbial activities and nutrient supply patterns are expected to change further, and these changes may have crucial implications for the productivity and biodiversity of alpine ecosystems.

The response of zooplankton communities to the 2016 extreme hydrological cycle in floodplain lakes connected to the Yangtze River in China.

PubMed

Zhang, Kun; Xu, Mei; Wu, Qili; Lin, Zhi; Jiang, Fangyuan; Chen, Huan; Zhou, Zhongze

2018-06-04

The Huayanghe Lakes play an important role in the Yangtze floodplain in China and had extremely high water levels during the summer of 2016. Monitoring data was collected in an effort to understand the impact of this change on the crustacean zooplankton composition and abundance and the biomass variation in the Huayanghe Lakes between a regular hydrological cycle (RHC) and an extreme hydrological cycle (EHC). The crustacean zooplankton community composition, abundance, and biomass in the floodplain lakes were markedly affected by the water-level disturbance. The number of species was lower in the RHC, but the mean density and biomass decreased from 93.84 ± 13.29 ind./L and 6.11 ± 0.89 mg/L, respectively, in the RHC to 66.62 ± 10.88 ind./L and 1.22 ± 0.26 mg/L, respectively, in the EHC. Pearson correlations and redundancy analyses revealed the environmental factors with the most significant impact on the crustacean zooplankton community differed between the RHC and EHC cycles. Little previous information exists on the zooplankton in these lakes, and the present study provides data on the zooplankton composition, abundance, and biomass, both at baseline and in response to hydrological changes.

Historical record of polychlorinated biphenyls (PCBs) and special occurrence of PCB 209 in a shallow fresh-water lake from eastern China.

PubMed

Huo, Shouliang; Li, Chaocan; Xi, Beidou; Yu, Zhiqiang; Yeager, Kevin M; Wu, Fengchang

2017-10-01

Concentrations of polychlorinated biphenyls (PCBs) were measured in dated sediment cores collected from the fifth largest freshwater lake in China, Lake Chaohu, to investigate PCB temporal trends, accumulation, and environmental fate. Total PCB concentrations in Lake Choahu sediments ranged from 0.03 to 24.11 ng g -1 (d.w.). PCB 209 was the dominant congener, accounting for 45.5%-83.9% of total PCBs detected after the mid-20th century. All PCB congeners were positively correlated with total organic carbon (TOC) concentrations. TOC-normalized PCB concentrations exhibited three stages of variation over time: a slight increase from their emergence in the early 20th century, followed by a rapid increase since the late 1950s (peaking in the late 1980s), before a general decrease to the present. Both compositional PCB patterns and principal component analysis (PCA) indicated a source switch from commercial PCBs to other sources. Major contributions of PCB209 to total PCBs in Lake Chaohu sediments is a highlight of this study, with results showing that PCB209 was derived from the upstream city of Hefei, and the production of phthalocyanine-type pigments is the likely source of PCB209. Copyright © 2017 Elsevier Ltd. All rights reserved.

Potential transport pathways of dust emanating from the playa of Ebinur Lake, Xinjiang, in arid northwest China

NASA Astrophysics Data System (ADS)

Ge, Yongxiao; Abuduwaili, Jilili; Ma, Long; Wu, Na; Liu, Dongwei

2016-09-01

In this paper, the HYSPLIT model, driven with reanalysis meteorological data from 1978 to 2013, was used to understand the potential transport characteristics of dust and salt dust emanating from the playa of Ebinur Lake in arid northwest China. Daily air parcel trajectories were computed forward for 8 days from an origin centered over Ebinur Lake at 100 m above ground level. Air parcel trajectory density plots were mapped for seven levels: 0-100 m agl., 100-500 m agl., 500-1000 m agl., 1000-1500 m agl., 1500-2000 m agl., 2000-3000 m agl., and 3000-5000 m agl. These show that potential dust transport pathways have clear seasonal differentiation. The potential transport distance of dust and salt dust is greatest in spring and summer. In autumn and winter, the potential transport of the high-density air trajectory is below 1000 m traveling a shorter distance. Potential dust transport pathways showed notifying directivity in different seasons and heights. Southeast in spring and summer, and north to northeast in autumn and winter are the two main potential transport channels of dust and salt dust. Accordingly, dust and salt dust from the playa of Ebinur Lake may influence the atmospheric processes and biogeochemical cycles of a vast region. The main area of influence of dust and salt dust is close to the source area, and will significantly accelerate the melting of snow and ice in the Tianshan Mountains. This highlights the urgent need to combine remote sensing, isotope and other methods to further research the transport characteristics of dust and salt dust from the playa of the Ebinur Lake.

Ptilagrostis contracta (Stipeae, Poaceae), a New Species Endemic to Qinghai-Tibet Plateau.

PubMed

Zhang, Zhong-Shuai; Li, Ling-Lu; Chen, Wen-Li

2017-01-01

A new species, Ptilagrostis contracta, endemic to Qinghai-Tibet Plateau is described and illustrated. It is distinguished from other species in Ptilagrostis by having contracted panicles, 1-geniculate awns with hairy columns and scabrous bristles and evenly pubescent lemmas. Evidence from lemma epidermal pattern, cytology and molecular phylogenetic analyses based on the nuclear ITS sequence data confirm its systematic position in Ptilagrostis.

Hulun Lake's ecological health and evaluation of its' eutrophication

NASA Astrophysics Data System (ADS)

Li, W.; Yang, W.; Wang, X.; Huang, J.; Sun, B.; Li, X.

2013-12-01

Hulun Lake is the largest lake in the north of china. The special geological location determines its important position in regional environmental protection. In terms of Hulun Lake's current situation, this paper chooses the indexes of lake system, lake structure and lake condition. Based on the calculation of these indexes and related theory , the evaluation standards of Hulun Lake's ecological healthy system are worked out. The author used Analytic Hierarchy Process to determine the weight of each indicator layer and criteria layer, and then applied fuzzy-pattern recognition model to calculate, finally, identifying the status of Hulun Lake according to the degrees of all levels. At the same time, the author used an integrated nutrition state index method to do the eutrophication assessment. Evaluation results show that the current status of Hulun Lake is healthy and it is in the moderate level of eutrophication.

Organochlorine pesticides in fish from Taihu Lake, China, and associated human health risk assessment.

PubMed

Wang, Deqing; Yu, Yingxin; Zhang, Xinyu; Zhang, Dongping; Zhang, Shaohuan; Wu, Minghong

2013-12-01

Because contaminants and nutrients always coexist in fish, the risk from contaminants and the benefit from nutrients, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are also concomitant via fish consumption. To investigate the risk and benefit via fish consumption, concentrations of dichlorodiphenyltrichloroethane and its metabolites (DDTs), and hexachlorocyclohexanes (HCHs) in the whole- and portion-muscles of fish from Taihu Lake, China, were measured. Based on the contaminant data and nutrients from our previous study, and the associated risk and benefit via fish consumption were estimated. The concentrations of DDTs and HCHs in the whole-muscles ranged from 7.8 × 10² to 3.4×10³ pg g⁻¹ ww, and from 67.3 to 300 pg g⁻¹ ww, respectively. Of DDTs and HCHs measured, p,p'-DDE and β-HCH were respectively the most abundant pesticides. The composition profiles of DDTs and HCHs suggested that the pesticides were mainly historical residues. The benefit-risk quotient (BRQ) of EPA+DHA vs. POPs (persistent organic pollutants including data of DDTs, HCHs, and those of polychlorinated biphenyls and polybrominated diphenyl ethers cited from our previous study) via consumption of fish from Taihu Lake was calculated. As a result, to achieve the recommended EPA+DHA intake of 250 mg d⁻¹ for a healthy adult, the consumption of most fish species from the lake can cause cancer and non-cancer risks. However, the fish consumption at the rates of 44.9 g d⁻¹ by Chinese would not lead to the risks for most of the species. The results also suggested that the risk of consuming silver carp was generally lower than other fish species, and those of dorsal muscles were lower than ventral and tail muscles. Copyright © 2013 Elsevier Inc. All rights reserved.

High altitude medicine education in China: exploring a new medical education reform.

PubMed

Luo, Yongjun; Luo, Rong; Li, Weiming; Huang, Jianjun; Zhou, Qiquan; Gao, Yuqi

2012-03-01

China has the largest plateau in the world, which includes the whole of Tibet, part of Qinghai, Xinjiang, Yunnan, and Sichuan. The plateau area is about 257.2×10(4) km(2), which accounts for about 26.8% of the total area of China. According to data collected in 2006, approximately twelve million people were living at high altitudes, between 2200 to 5200 m high, on the Qinghai-Tibetan Plateau. Therefore, there is a need for medical workers who are trained to treat individuals living at high altitudes. To train undergraduates in high altitude medicine, the College of High Altitude Military Medicine was set up at the Third Military Medical University (TMMU) in Chongqing in 1999. This is the only school to teach high altitude medicine in China. Students at TMMU study natural and social sciences, basic medical sciences, clinical medical sciences, and high altitude medicine. In their 5(th) year, students work as interns at the General Hospital of Tibet Military Command in Lhasa for 3 months, where they receive on-site teaching. The method of on-site teaching is an innovative approach for training in high altitude medicine for undergraduates. Three improvements were implemented during the on-site teaching component of the training program: (1) standardization of the learning progress; (2) integration of formal knowledge with clinical experience; and (3) coaching students to develop habits of inquiry and to engage in ongoing self-improvement to set the stage for lifelong learning. Since the establishment of the innovative training methods in 2001, six classes of high altitude medicine undergraduates, who received on-site teaching, have graduated and achieved encouraging results. This evidence shows that on-site teaching needs to be used more widely in high altitude medicine education.

Preliminary estimation of the realistic optimum temperature for vegetation growth in China.

PubMed

Cui, Yaoping

2013-07-01

The estimation of optimum temperature of vegetation growth is very useful for a wide range of applications such as agriculture and climate change studies. Thermal conditions substantially affect vegetation growth. In this study, the normalized difference vegetation index (NDVI) and daily temperature data set from 1982 to 2006 for China were used to examine optimum temperature of vegetation growth. Based on a simple analysis of ecological amplitude and Shelford's law of tolerance, a scientific framework for calculating the optimum temperature was constructed. The optimum temperature range and referenced optimum temperature (ROT) of terrestrial vegetation were obtained and explored over different eco-geographical regions of China. The results showed that the relationship between NDVI and air temperature was significant over almost all of China, indicating that terrestrial vegetation growth was closely related to thermal conditions. ROTs were different in various regions. The lowest ROT, about 7.0 °C, occurred in the Qinghai-Tibet Plateau, while the highest ROT, more than 22.0 °C, occurred in the middle and lower reaches of the Yangtze River and the Southern China region.

Preliminary Estimation of the Realistic Optimum Temperature for Vegetation Growth in China

NASA Astrophysics Data System (ADS)

Cui, Yaoping

2013-07-01

The estimation of optimum temperature of vegetation growth is very useful for a wide range of applications such as agriculture and climate change studies. Thermal conditions substantially affect vegetation growth. In this study, the normalized difference vegetation index (NDVI) and daily temperature data set from 1982 to 2006 for China were used to examine optimum temperature of vegetation growth. Based on a simple analysis of ecological amplitude and Shelford's law of tolerance, a scientific framework for calculating the optimum temperature was constructed. The optimum temperature range and referenced optimum temperature (ROT) of terrestrial vegetation were obtained and explored over different eco-geographical regions of China. The results showed that the relationship between NDVI and air temperature was significant over almost all of China, indicating that terrestrial vegetation growth was closely related to thermal conditions. ROTs were different in various regions. The lowest ROT, about 7.0 °C, occurred in the Qinghai-Tibet Plateau, while the highest ROT, more than 22.0 °C, occurred in the middle and lower reaches of the Yangtze River and the Southern China region.

Linkage between Three Gorges Dam impacts and the dramatic recessions in China’s largest freshwater lake, Poyang Lake

PubMed Central

Mei, Xuefei; Dai, Zhijun; Du, Jinzhou; Chen, Jiyu

2015-01-01

Despite comprising a small portion of the earth’s surface, lakes are vitally important for global ecosystem cycling. However, lake systems worldwide are extremely fragile, and many are shrinking due to changing climate and anthropogenic activities. Here, we show that Poyang Lake, the largest freshwater lake in China, has experienced a dramatic and prolonged recession, which began in late September of 2003. We further demonstrate that abnormally low levels appear during October, 28 days ahead of the normal initiation of the dry season, which greatly imperiled the lake’s wetland areas and function as an ecosystem for wintering waterbirds. An increase in the river-lake water level gradient induced by the Three Gorges Dam (TGD) altered the lake balance by inducing greater discharge into the Changjiang River, which is probably responsible for the current lake shrinkage. Occasional episodes of arid climate, as well as local sand mining, will aggravate the lake recession crisis. Although impacts of TGD on the Poyang Lake recession can be overruled by episodic extreme droughts, we argue that the average contributions of precipitation variation, human activities in the Poyang Lake catchment and TGD regulation to the Poyang Lake recession can be quantified as 39.1%, 4.6% and 56.3%, respectively. PMID:26657816

Linkage between Three Gorges Dam impacts and the dramatic recessions in China’s largest freshwater lake, Poyang Lake

NASA Astrophysics Data System (ADS)

Mei, Xuefei; Dai, Zhijun; Du, Jinzhou; Chen, Jiyu

2015-12-01

Despite comprising a small portion of the earth’s surface, lakes are vitally important for global ecosystem cycling. However, lake systems worldwide are extremely fragile, and many are shrinking due to changing climate and anthropogenic activities. Here, we show that Poyang Lake, the largest freshwater lake in China, has experienced a dramatic and prolonged recession, which began in late September of 2003. We further demonstrate that abnormally low levels appear during October, 28 days ahead of the normal initiation of the dry season, which greatly imperiled the lake’s wetland areas and function as an ecosystem for wintering waterbirds. An increase in the river-lake water level gradient induced by the Three Gorges Dam (TGD) altered the lake balance by inducing greater discharge into the Changjiang River, which is probably responsible for the current lake shrinkage. Occasional episodes of arid climate, as well as local sand mining, will aggravate the lake recession crisis. Although impacts of TGD on the Poyang Lake recession can be overruled by episodic extreme droughts, we argue that the average contributions of precipitation variation, human activities in the Poyang Lake catchment and TGD regulation to the Poyang Lake recession can be quantified as 39.1%, 4.6% and 56.3%, respectively.

Niche conservatism in Gynandropaa frogs on the southeastern Qinghai-Tibetan Plateau.

PubMed

Hu, Junhua; Broennimann, Olivier; Guisan, Antoine; Wang, Bin; Huang, Yan; Jiang, Jianping

2016-09-07

The role of ecological niche in lineage diversification has been the subject of long-standing interest of ecologists and evolutionary biologists. Gynandropaa frogs diversified into three independent clades endemic to the southeastern Qinghai-Tibetan Plateau. Here, we address the question whether these clades kept the same niche after separation, and what it tells us about possible diversification processes. We applied predictions in geographical (G)-space and tests of niche conservatism in environmental (E)-space. Niche models in G-space indicate separate regions with high suitability for the different clades, with some potential areas of sympatry. While the pair of central and eastern clades displayed the largest niche overlap for most variables, and strict niche equivalency was rejected for all clade-pairs, we found no strong evidence for niche divergence, but rather the signature of niche conservatism compared to null models in E-space. These results suggest a common ancestral ecological niche, and as such give good support to divergence through allopatric speciation, but alternative explanations are also possible. Our findings illustrate how testing for niche conservatism in lineage diversification can provide insights into underlying speciation processes, and how this information may guide further research and conservation practices, as illustrated here for amphibians on the Qinghai-Tibetan Plateau.

Movement analysis of free-grazing domestic ducks in Poyang Lake, China: A disease connection

USGS Publications Warehouse

Prosser, Diann J.; Palm, Eric C.; Takekawa, John Y.; Zhao, Delong; Xiao, Xiangming; Li, Peng; Liu, Ying; Newman, Scott H.

2015-01-01

Previous work suggests domestic poultry are important contributors to the emergence and transmission of highly pathogenic avian influenza throughout Asia. In Poyang Lake, China, domestic duck production cycles are synchronized with arrival and departure of thousands of migratory wild birds in the area. During these periods, high densities of juvenile domestic ducks are in close proximity to migratory wild ducks, increasing the potential for the virus to be transmitted and subsequently disseminated via migration. In this paper, we use GPS dataloggers and dynamic Brownian bridge models to describe movements and habitat use of free-grazing domestic ducks in the Poyang Lake basin and identify specific areas that may have the highest risk of H5N1 transmission between domestic and wild birds. Specifically, we determine relative use by free-grazing domestic ducks of natural wetlands, which are the most heavily used areas by migratory wild ducks, and of rice paddies, which provide habitat for resident wild ducks and lower densities of migratory wild ducks. To our knowledge, this is the first movement study on domestic ducks, and our data show potential for free-grazing domestic ducks from farms located near natural wetlands to come in contact with wild waterfowl, thereby increasing the risk for disease transmission. This study provides an example of the importance of movement ecology studies in understanding dynamics such as disease transmission on a complicated landscape.

Movement analysis of free-grazing domestic ducks in Poyang Lake, China: a disease connection.

PubMed

Prosser, Diann J; Palm, Eric C; Takekawa, John Y; Zhao, Delong; Xiao, Xiangming; Li, Peng; Liu, Ying; Newman, Scott H

2016-01-01

Previous work suggests domestic poultry are important contributors to the emergence and transmission of highly pathogenic avian influenza throughout Asia. In Poyang Lake, China, domestic duck production cycles are synchronized with arrival and departure of thousands of migratory wild birds in the area. During these periods, high densities of juvenile domestic ducks are in close proximity to migratory wild ducks, increasing the potential for the virus to be transmitted and subsequently disseminated via migration. In this paper, we use GPS dataloggers and dynamic Brownian bridge models to describe movements and habitat use of free-grazing domestic ducks in the Poyang Lake basin and identify specific areas that may have the highest risk of H5N1 transmission between domestic and wild birds. Specifically, we determine relative use by free-grazing domestic ducks of natural wetlands, which are the most heavily used areas by migratory wild ducks, and of rice paddies, which provide habitat for resident wild ducks and lower densities of migratory wild ducks. To our knowledge, this is the first movement study on domestic ducks, and our data show potential for free-grazing domestic ducks from farms located near natural wetlands to come in contact with wild waterfowl, thereby increasing the risk for disease transmission. This study provides an example of the importance of movement ecology studies in understanding dynamics such as disease transmission on a complicated landscape.

Malachite green and chloramphenicol in aquatic products from regions around Dongting Lake in Hunan, China.

PubMed

He, Jiang; Cui, Jingzhen

2016-01-01

Aquatic products are important sources of animal proteins in human diet, especially in developing countries. As such, the safety of aquatic products is of primary concern. In this study, a standard method is used to detect malachite green (MG) and chloramphenicol (CAP) and to analyse the contents of these banned chemicals in turtle, mandarin fish and grass carp sampled from the region surrounding Dongting Lake area in Hunan, China. Results showed that 10.6% of the samples were MG-positive, most of them turtles. CAP was found in 8.3% of the samples, mostly in mandarin fish. These data indicated that these banned substances are still used in the surveyed area. Hence, adequate strategies must be implemented by the local government to control these banned substances.

Network Skewness Measures Resilience in Lake Ecosystems

NASA Astrophysics Data System (ADS)

Langdon, P. G.; Wang, R.; Dearing, J.; Zhang, E.; Doncaster, P.; Yang, X.; Yang, H.; Dong, X.; Hu, Z.; Xu, M.; Yanjie, Z.; Shen, J.

2017-12-01

Changes in ecosystem resilience defy straightforward quantification from biodiversity metrics, which ignore influences of community structure. Naturally self-organized network structures show positive skewness in the distribution of node connections. Here we test for skewness reduction in lake diatom communities facing anthropogenic stressors, across a network of 273 lakes in China containing 452 diatom species. Species connections show positively skewed distributions in little-impacted lakes, switching to negative skewness in lakes associated with human settlement, surrounding land-use change, and higher phosphorus concentration. Dated sediment cores reveal a down-shifting of network skewness as human impacts intensify, and reversal with recovery from disturbance. The appearance and degree of negative skew presents a new diagnostic for quantifying system resilience and impacts from exogenous forcing on ecosystem communities.

Diversity and distribution of archaea community along a stratigraphic permafrost profile from Qinghai-Tibetan Plateau, China.

PubMed

Wei, Shiping; Cui, Hongpeng; He, Hao; Hu, Fei; Su, Xin; Zhu, Youhai

2014-01-01

Accompanying the thawing permafrost expected to result from the climate change, microbial decomposition of the massive amounts of frozen organic carbon stored in permafrost is a potential emission source of greenhouse gases, possibly leading to positive feedbacks to the greenhouse effect. In this study, the community composition of archaea in stratigraphic soils from an alpine permafrost of Qinghai-Tibetan Plateau was investigated. Phylogenic analysis of 16S rRNA sequences revealed that the community was predominantly constituted by Crenarchaeota and Euryarchaeota. The active layer contained a proportion of Crenarchaeota at 51.2%, with the proportion of Euryarchaeota at 48.8%, whereas the permafrost contained 41.2% Crenarchaeota and 58.8% Euryarchaeota, based on 16S rRNA gene sequence analysis. OTU1 and OTU11, affiliated to Group 1.3b/MCG-A within Crenarchaeota and the unclassified group within Euryarchaeota, respectively, were widely distributed in all sediment layers. However, OTU5 affiliated to Group 1.3b/MCG-A was primarily distributed in the active layers. Sequence analysis of the DGGE bands from the 16S rRNAs of methanogenic archaea showed that the majority of methanogens belonged to Methanosarcinales and Methanomicrobiales affiliated to Euryarchaeota and the uncultured ZC-I cluster affiliated to Methanosarcinales distributed in all the depths along the permafrost profile, which indicated a dominant group of methanogens occurring in the cold ecosystems.

Diversity and Distribution of Archaea Community along a Stratigraphic Permafrost Profile from Qinghai-Tibetan Plateau, China

PubMed Central

Cui, Hongpeng; He, Hao; Hu, Fei; Su, Xin; Zhu, Youhai

2014-01-01

Accompanying the thawing permafrost expected to result from the climate change, microbial decomposition of the massive amounts of frozen organic carbon stored in permafrost is a potential emission source of greenhouse gases, possibly leading to positive feedbacks to the greenhouse effect. In this study, the community composition of archaea in stratigraphic soils from an alpine permafrost of Qinghai-Tibetan Plateau was investigated. Phylogenic analysis of 16S rRNA sequences revealed that the community was predominantly constituted by Crenarchaeota and Euryarchaeota. The active layer contained a proportion of Crenarchaeota at 51.2%, with the proportion of Euryarchaeota at 48.8%, whereas the permafrost contained 41.2% Crenarchaeota and 58.8% Euryarchaeota, based on 16S rRNA gene sequence analysis. OTU1 and OTU11, affiliated to Group 1.3b/MCG-A within Crenarchaeota and the unclassified group within Euryarchaeota, respectively, were widely distributed in all sediment layers. However, OTU5 affiliated to Group 1.3b/MCG-A was primarily distributed in the active layers. Sequence analysis of the DGGE bands from the 16S rRNAs of methanogenic archaea showed that the majority of methanogens belonged to Methanosarcinales and Methanomicrobiales affiliated to Euryarchaeota and the uncultured ZC-I cluster affiliated to Methanosarcinales distributed in all the depths along the permafrost profile, which indicated a dominant group of methanogens occurring in the cold ecosystems. PMID:25525409

Heavy Metal Pollution, Fractionation, and Potential Ecological Risks in Sediments from Lake Chaohu (Eastern China) and the Surrounding Rivers

PubMed Central

Zhang, Lei; Liao, Qianjiahua; Shao, Shiguang; Zhang, Nan; Shen, Qiushi; Liu, Cheng

2015-01-01

Heavy metal (Cr, Ni, Cu, Zn, Cd, and Pb) pollution, fractionation, and ecological risks in the sediments of Lake Chaohu (Eastern China), its eleven inflowing rivers and its only outflowing river were studied. An improved BCR (proposed by the European Community Bureau of Reference) sequential extraction procedure was applied to fractionate heavy metals within sediments, a geoaccumulation index was used to assess the extent of heavy metal pollution, and a risk assessment code was applied to evaluate potential ecological risks. Heavy metals in the Shuangqiao and Nanfei Rivers were generally higher than the other studied sites. Of the three Lake Chaohu sites, the highest concentrations were identified in western Chaohu. Heavy metal pollution and ecological risks in the lake’s only outflowing river were similar to those in the eastern region of the lake, to which the river is connected. Heavy metal concentrations occurred in the following order: Cd > Zn > Cu > Pb ≈ Ni ≈ Cr. Cr, Ni, and Cu made up the largest proportion of the residual fraction, while Cd was the most prominent metal in the exchangeable and carbonate-included fraction. Cd posed the greatest potential ecological risk; the heavy metals generally posed risks in the following order: Cd > Zn > Cu > Ni > Pb > Cr. PMID:26561822

Simulation and evaluation of pollution load reduction scenarios for water environmental management: a case study of inflow river of Taihu Lake, China.

PubMed

Zhang, Ruibin; Qian, Xin; Zhu, Wenting; Gao, Hailong; Hu, Wei; Wang, Jinhua

2014-09-09

In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of "Treatment after Pollution" has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives.

Simulation and Evaluation of Pollution Load Reduction Scenarios for Water Environmental Management: A Case Study of Inflow River of Taihu Lake, China

PubMed Central

Zhang, Ruibin; Qian, Xin; Zhu, Wenting; Gao, Hailong; Hu, Wei; Wang, Jinhua

2014-01-01

In the beginning of the 21st century, the deterioration of water quality in Taihu Lake, China, has caused widespread concern. The primary source of pollution in Taihu Lake is river inflows. Effective pollution load reduction scenarios need to be implemented in these rivers in order to improve the water quality of Taihu Lake. It is important to select appropriate pollution load reduction scenarios for achieving particular goals. The aim of this study was to facilitate the selection of appropriate scenarios. The QUAL2K model for river water quality was used to simulate the effects of a range of pollution load reduction scenarios in the Wujin River, which is one of the major inflow rivers of Taihu Lake. The model was calibrated for the year 2010 and validated for the year 2011. Various pollution load reduction scenarios were assessed using an analytic hierarchy process, and increasing rates of evaluation indicators were predicted using the Delphi method. The results showed that control of pollution from the source is the optimal method for pollution prevention and control, and the method of “Treatment after Pollution” has bad environmental, social and ecological effects. The method applied in this study can assist for environmental managers to select suitable pollution load reduction scenarios for achieving various objectives. PMID:25207492

Ecological regime shifts and changes of lake ecosystem service in a shallow Yangtze lake (Taibai Lake, China) over the past 150 years

NASA Astrophysics Data System (ADS)

Dong, X.; Xu, M.; Yang, X.

2017-12-01

Shallow lakes provide a range of ecosystem services such as water supply, biodiversity, aquaculture, tourism, shipping and flood regulation. Over recent decades, many lakes have become severely deteriorated due to a coupled natural and human disturbance. Given the limited monitoring records, however, we still have little knowledge on how, when and why those lake experienced ecological status shifts, and how the lake ecosystem service changed. Paleolimnological techniques were widely used in understanding the historical environmental and ecological changes. Here, we chose a typical eutrophic shallow lake, Taibai Lake, and acquired geochemistry proxies, grain size, diatom, cladocera and chironomid from a 210Pb and 137Cs dated sediment core. Document records and monitoring data are also included as important marks of social and environmental change. A T-test based algorithm of STARS reveal at least two ecological shifts, respectively in the 1960s and the 1990s. The sudden shift in the 1960s is supposed to be influenced by a dam and sluice construction in the 1950s and another shift in the 1990s should be a critical transition due to the alternation of ecosystem structure for higher fishery production. Correspondingly, lake ecosystem service (LES) also experienced significant changes. Prior to 1930s, different types of LES kept relatively stable with low values. With the dam construction in the 1960s, the changed hydrological condition led to gradual increases in both regulation and provision service. However, with much effort on fishery and reclamation, the regulation service of the lake decreased, exhibiting a tradeoff among LES. After 1990s, with intense aquaculture, most types of LSE suffered a further decrease. The long-term records exhibited that ecosystem services in primary productivity and biodiversity maintenance increased (synergies) whereas services in water-purification and climate regulating decreased significantly (tradeoffs) since 1950s, when local

[Analysis on the results of etiology and serology of plague in Qinghai province from 2001 to 2010].

PubMed

Yang, Yonghai; Wang, Mei; Zhao, Xiaolong; Zhao, Zhongzhi; Zhang, Aiping; Wei, Rongjie; Wei, Baiqing; Wang, Zuyun

2014-02-01

To analyze the results of etiology and serology of plague among human and infected animals in Qinghai province from 2001 to 2010. Thirty-seven cases of human infected with plague, 53 541 different animal samples, 5 685 sets of vector insects flea and 49 039 different animal serum samples were obtained between 2001 and 2010. A total of 7 811 samples of serum from healthy farmers and herdsmen in 14 counties in Qinghai from 2005 to 2007 were collected. Yersinia pestis (Y. pestis) were detected in visceral and secretions from human, infected animals and vector insects, respectively. Plague antigen was detected by reverse indirect hemagglutination assay (RIHA) in those samples. Indirect hemagglutination assay (IHA) was used to test plague FI antibody in serum of human and infected animals. 37 human plague cases were confirmed, 21 strains of plague Y. pestis were isolated from human cases and 14 positive were detected out. 133 of 7 811 samples of human serum were IHA positive, with the positive rate at 1.7%. A total of 146 strains of plague were isolated from infected animals and vector insects, 99 out of which were from infected animals, with a ratio of Marmota himalayan at 72.7% (72/99) and the other 47 were from vector insects, with a ratio of callopsylla solaris at 68.1% (32/47). The number of IHA and PIHA positive were 300 and 10, respectively. A total of 3 animals and 3 insects species were identified as new epidemic hosts for plague. The natural plague focus of Microtus fuscus was discovered and confirmed and coexisted with natural focus of Marmota himalayan in Chengduo county, Yushu prefecture. The epidemic situation of plague is distributed mainly in Haixi, Yushu and Hainan prefectures. From 2001 to 2010, animal infected with plague was detected in successive years and human plague was very common in Qinghai. New infected animals and vector insects species and new epidemic areas were confirmed, hence the trend of plague prevalence for humans and animals is very

Changes in frozen ground and vegetation on northern slopes of the Bayan Har Mountains on northeastern Qinghai-Tibetan Plateau, Southwest China

NASA Astrophysics Data System (ADS)

Jin, X.

2017-12-01

The Bayan Har Mountains (BHM) on northeastern Qinghai-Tibetan Plateau, Southwest China, is representative of elevational permafrost. Permafrost in the BHM is mostly warm (<-1°C) and mosaicked with seasonally frozen ground and taliks in discontinuous permafrost zones. Warming climate has led, is leading, and will lead to marked and profound permafrost changes. Consequently, permafrost changes significantly affect hydrology, ecology and engineered infrastructures in the source area of Yellow River. Due to the limited monitoring data, however, the permafrost in the BHM is poorly understood. Based on temperature measurements from boreholes established since 2010 and other historical archives, and field investigations since 2011, this study aims at analyzing spatiotemporal changes of permafrost and their associations with vegetation characteristics. Preliminary results show that: (1) It is evident that permafrost temperatures decrease with rising elevations. Mean annual ground temperature is generally above 0°C at elevations below 4,350 m a. s. l.; Above 4,520 m a. s. l. , permafrost temperature is lower than -0.5°C; (2) From 2011 to 2016, permafrost temperatures increased by 0.02-0.11°C at elevations below 4,400 m a. s. l. , but they decreased by 0.04°C above 4,520 m a. s. l.; (3) About 64 species of vegetation were found around the boreholes. Mesoxerophytes are the dominant species at elevations below 4,400 m a. s. l. in the areas of seasonally frozen ground, and; the cyperaceae dominate above 4,520 m a. s. l. in the permafrost zones. With rising elevations, aboveground biomass increases, but the species richness declines, maybe due to the variations in hydrothermal combinations and grazing. Under a warming and wetting climate, permafrost degradation, as evidenced by the reduction in areal extent of permafrost and thickening active layer, may result in declining or depletion of near-surface soil moisture due to the lowering permafrost and supra-permafrost water

Holocene vegetation and climate dynamics of NE China based on the pollen record from Sihailongwan Maar Lake

NASA Astrophysics Data System (ADS)

Stebich, Martina; Rehfeld, Kira; Schlütz, Frank; Tarasov, Pavel E.; Liu, Jiaqi; Mingram, Jens

2015-09-01

High-resolution palynological analysis on annually laminated sediments of Sihailongwan Maar Lake (SHL) provides new insights into the Holocene vegetation and climate dynamics of NE China. The robust chronology of the presented record is based on varve counting and AMS radiocarbon dates from terrestrial plant macro-remains. In addition to the qualitative interpretation of the pollen data, we provide quantitative reconstructions of vegetation and climate based on the method of biomization and weighted averaging partial least squares regression (WA-PLS) technique, respectively. Power spectra were computed to investigate the frequency domain distribution of proxy signals and potential natural periodicities. Pollen assemblages, pollen-derived biome scores and climate variables as well as the cyclicity pattern indicate that NE China experienced significant changes in temperature and moisture conditions during the Holocene. Within the earliest phase of the Holocene, a large-scale reorganization of vegetation occurred, reflecting the reconstructed shift towards higher temperatures and precipitation values and the initial Holocene strengthening and northward expansion of the East Asian summer monsoon (EASM). Afterwards, summer temperatures remain at a high level, whereas the reconstructed precipitation shows an increasing trend until approximately 4000 cal. yr BP. Since 3500 cal. yr BP, temperature and precipitation values decline, indicating moderate cooling and weakening of the EASM. A distinct periodicity of 550-600 years and evidence of a Mid-Holocene transition from a temperature-triggered to a predominantly moisture-triggered climate regime are derived from the power spectra analysis. The results obtained from SHL are largely consistent with other palaeoenvironmental records from NE China, substantiating the regional nature of the reconstructed vegetation and climate patterns. However, the reconstructed climate changes contrast with the moisture evolution recorded in

[Subnational analysis of probability of premature mortality caused by four main non-communicable diseases in China during 1990-2015 and " Health China 2030" reduction target].

PubMed

Zeng, X Y; Li, Y C; Liu, S W; Wang, L J; Liu, Y N; Liu, J M; Zhou, M G

2017-03-06

Objective: To investigate the current status, temporal trend and achieving Health China 2030 reduction target of probability of premature mortality caused by four main non-communicable diseases (NCDs) including cardiovascular and cerebrovascular diseases, tumour, diabetes, and chronic respiratory disease in China both at national and provincial level during 1990 to 2015. Methods: Using the results of Global Burden of Disease study 2015 (GBD 2015), according to the method of calculating premature mortality probability recommended by WHO, the current status and temporal trend by different gender from 1990 to 2015 were calculated, analyzed, and compared. Referring to " Health China 2030" target of reduction 30% of probability of premature mortality caused by major NCDs, we evaluated the difficulty of achieving the reduction target among provinces (not including Taiwan). Results: From 1990 to 2015, the probabilities of premature mortality in cardiovascular and cerebrovascular diseases, tumour, and chronic respiratory disease were all declined consistently for both men and women in China, the total of four main NCDs decreased from 30.69% to 18.54% with higher decreasing in women (from 25.97% to 12.40%) than that in men (from 34.94% to 24.19%). In 2015, the top five provinces in terms of probability of premature mortality caused by four main NCDs were Qinghai (28.81%), Tibet (25.88%), Guizhou (24.67%), Guangxi (23.56%), and Xinjiang (23.21%) in turn, while the top five provinces with the lowest probability were Shanghai (8.40%), Beijing (9.39%), Hong Kong (10.10%), Macao (10.31%), and Zhejiang (11.70%). If achieving the " Health China 2030" target, the probabilities of premature mortality in Qinghai and Tibet with the highest probability should decline to about 20.17%, and 18.12%, respectively in 2030, while 5.88%, and 6.57% in Shanghai and Beijing, respectively. From 1990 to 2015, the probability of premature mortality of four main NCDs declined by 2.00% a year on

Environmental impact assessment and environmental audit in large-scale public infrastructure construction: the case of the Qinghai-Tibet Railway.

PubMed

He, Guizhen; Zhang, Lei; Lu, Yonglong

2009-09-01

Large-scale public infrastructure projects have featured in China's modernization course since the early 1980s. During the early stages of China's rapid economic development, public attention focused on the economic and social impact of high-profile construction projects. In recent years, however, we have seen a shift in public concern toward the environmental and ecological effects of such projects, and today governments are required to provide valid environmental impact assessments prior to allowing large-scale construction. The official requirement for the monitoring of environmental conditions has led to an increased number of debates in recent years regarding the effectiveness of Environmental Impact Assessments (EIAs) and Governmental Environmental Audits (GEAs) as environmental safeguards in instances of large-scale construction. Although EIA and GEA are conducted by different institutions and have different goals and enforcement potential, these two practices can be closely related in terms of methodology. This article cites the construction of the Qinghai-Tibet Railway as an instance in which EIA and GEA offer complementary approaches to environmental impact management. This study concludes that the GEA approach can serve as an effective follow-up to the EIA and establishes that the EIA lays a base for conducting future GEAs. The relationship that emerges through a study of the Railway's construction calls for more deliberate institutional arrangements and cooperation if the two practices are to be used in concert to optimal effect.

Nontarget Mass Spectrometry Reveals New Perfluoroalkyl Substances in Fish from the Yangtze River and Tangxun Lake, China.

PubMed

Liu, Yanna; Qian, Manli; Ma, Xinxin; Zhu, Lingyan; Martin, Jonathan W

2018-05-15

Nontarget high-resolution mass spectrometry (Nt-HRMS) has been proven useful for the identification of unknown poly- and perfluoroalkyl substances (PFASs) in commercial products and water, but applications to biological samples are limited. China is the major PFAS-manufacturing nation; thus, here, we adapted our Nt-HRMS methods to fish collected from the Yangtze River and Tangxun Lake to discover potentially bioaccumulative PFASs in aquatic organisms destined for human consumption. In addition to traditional PFASs, over 330 other fluorinated analytes belonging to 10 classes of PFASs were detected among the pooled fish livers, including 6 sulfonate classes, 2 amine classes, 1 carboxylate class, and 1 N-heterocycle class. One class was detected in samples from both locations, 8 classes were detected exclusively in Tangxun Lake fish, and 1 class was detected exclusively in Yangtze River fish, 10 km downstream of a fluorochemical manufacturing site where we first reported these substances in wastewater 3 years ago. Overall, 4 of the PFAS classes (>165 analytes) are reported for the first time here. Wider monitoring and toxicological testing should be a priority for understanding the health risks posed to people and wildlife exposed to these substances.

Landslides and Earthquake Lakes from the Wenchuan, China Earthquake - Can it Happen in the U.S.?

NASA Astrophysics Data System (ADS)

Stenner, H.; Cydzik, K.; Hamilton, D.; Cattarossi, A.; Mathieson, E.

2008-12-01

The May 12, 2008 M7.9 Wenchuan, China earthquake destroyed five million homes and schools, causing over 87,650 deaths. Landslides, a secondary effect of the shaking, caused much of the devastation. Debris flows buried homes, rock falls crushed cars, and landslides dammed rivers. Blocked roads greatly impeded emergency access, delaying response. Our August 2008 field experience in the affected area reminded us that the western United States faces serious risks posed by earthquake-induced landslides. The topography of the western U.S. is less extreme than that near Wenchuan, but earthquakes may still cause devastating landslides, damming rivers and blocking access to affected areas. After the Wenchuan earthquake, lakes rapidly rose behind landslide dams, threatening millions of lives. One landslide above Beichuan City created Tangjiashan Lake, a massive body of water upstream of Mianyang, an area with 5.2 million people, 30,000 of whom were killed in the quake. Potential failure of the landslide dam put thousands more people at risk from catastrophic flooding. In 1959, the M7.4 Hebgen Lake earthquake in Montana caused a large landslide, which killed 19 people and dammed the Madison River. The Army Corps excavated sluices to keep the dam from failing catastrophically. The Hebgen Lake earthquake ultimately caused 28 deaths, mostly from landslides, but the affected region was sparsely populated. Slopes prone to strong earthquake shaking and landslides in California, Washington, and Oregon have much larger populations at risk. Landslide hazards continue after the earthquake due to the effect strong shaking has on hillslopes, particularly when subjected to subsequent rain. These hazards must be taken into account. Once a landslide blocks a river, rapid and thoughtful action is needed. The Chinese government quickly and safely mitigated landslide dams that posed the greatest risk to people downstream. It took expert geotechnical advice, the speed and resources of the army

Examining the relationship between mercury and organic matter in lake sediments along a latitudinal transect in subarctic Canada

NASA Astrophysics Data System (ADS)

Galloway, Jennifer M.; Sanei, Hamed; Parsons, Michael; Swindles, Graeme T.; Macumber, Andrew L.; Patterson, R. Timothy; Palmer, Michael; Falck, Hendrik

2016-04-01

matter and mercury in recent lake sediment: the physical-geochemical aspects. Appl Geochem 21: 1900-12. 2Outridge, P.M., Sanei, H., Stern, G.A., Hamilton, P.B., Goodarzi, F. 2007. Evidence for control of mercury accumulation rates in Canadian high Arctic lake sediments by variations of aquatic primary productivity. Environ Sci Technol 41: 5259-65. 3Wu, F., Zu, L., Liao, H., Guo, F., Zhao, X., Giesy, J. 2013. Relationship between mercury and organic carbon in sediment cores from Lakes Qinghai and Chenghai, China. J Soils Sediments 13: 1084-1092.4Kirk, J.L., Muir, D.C.G., Antoniades, D., Douglas, M.S.V., Evans, M.S., Jackson, T.A., Kling, H., Lamoureux, S., Lim, D.S.S., Pienitz, R., Smol, J.P., Stewart, K., Wang, X., Yang, F. 2011. Response to comment on climate change and mercury accumulation in Canadian high and subarctic lakes. Environ Sci Technol 45: 6705-06.5Deison, R., Smol, J.P., Kokelj, S.V., Pisaric, M.F.J., Kimpe, L.E., Poulain, A.J., Sanei, H., Theinpoint, J.R., Blais, J.M. 2012. Spatial and temporal assessment of mercury and organic matter in thermokarst affected lakes of the Mackenzie Delta Uplands, NT, Canada. Environ Sci Tech 46: 8748-55.

Changing land use and its impact on the habitat suitability for wintering Anseriformes in China's Poyang Lake region.

PubMed

Tang, Xuguang; Li, Hengpeng; Xu, Xibao; Yang, Guishan; Liu, Guihua; Li, Xinyan; Chen, Dongqiang

2016-07-01

As an internationally important wetland for migratory waterbirds, China's Poyang Lake region has experienced substantial changes in land use during the past two decades owing to climate change and anthropogenic disturbances. Recent dam constructions on the Yangtze River and its tributaries for agriculture and hydroelectric power exert strong effects on the hydrological regimes of this lake. However, few studies have investigated how the land-use changes through time affect the habitat suitability for wintering Anseriformes-the largest community in this region. Thus, it is necessary to timely monitor changes in the habitat quality and understand the potential factors that alter it. In this study, three periods (1995, 2005 and 2014) of typical environmental indicators that have direct impacts on foraging and resting for the Anserformes, including proximity to water (density of lakes, rivers and ponds), human disturbances (density of residences and various road networks), preferred land cover types and food availability (NDVI), are integrated to develop a habitat suitability index model for habitat mapping. The results indicate that long-term lake shrinkage in low-water periods led to greatly expanded wetlands in these years, which provided more suitable habitat for migratory waterfowl. The amount of highly suitable habitat in 2014 was nearly twice as much as in 1995. Recent survey data from 1997 to 2013 also revealed an increase in the population size, and confirmed the improvement of habitat suitability in the Poyang Lake region. Spatial analysis revealed that land use changes contributed most to the improved habitat coverage between 1995 and 2014. However, the relative significances of these transformations for highly suitable and moderately suitable habitats are strikingly different. Increases in wetland and paddy field area are the main reasons for explaining these improvements, respectively. The framework model proposed in this study will help governments to

Organochlorine compounds and polycyclic aromatic hydrocarbons in surface sediment from Baiyangdian Lake, North China: concentrations, sources profiles and potential risk.

PubMed

Hu, Guocheng; Luo, Xiaojun; Li, Fengchao; Dai, Jiayin; Guo, Jianyang; Chen, Shejun; Hong, Cao; Mai, Bixian; Xu, Muqi

2010-01-01

Organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs) were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river (Fuhe River) in North China. Total concentrations of OCPs, PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng/g, 2.3 to 197.8 ng/g, and 101.3 to 6360.5 ng/g, respectively. The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake. For hexachlorocyclohexane (HCHs) and dichlorodiphenytrichloroethanes (DDTs), alpha-HCH and p,p'-DDT were predominant isomers; while for PCBs, PCB 28/31, PCB 40/103, PCB 60, PCB 101, and PCB 118 were predominant congeners. Possible sources derived from historical usage for OCPs and incomplete combustion fuel, wood, and coal and exhaustion of boats or cars for PAHs. Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.

Decline in Chinese lake phosphorus concentration accompanied by shift in sources since 2006

NASA Astrophysics Data System (ADS)

Tong, Yindong; Zhang, Wei; Wang, Xuejun; Couture, Raoul-Marie; Larssen, Thorjørn; Zhao, Yue; Li, Jing; Liang, Huijiao; Liu, Xueyan; Bu, Xiaoge; He, Wei; Zhang, Qianggong; Lin, Yan

2017-07-01

Domestic wastewater and agricultural activities are important sources of nutrient pollutants such as phosphorus and nitrogen. Upon reaching freshwater, these nutrients can lead to extensive growth of harmful algae, which results in eutrophication. Many Chinese lakes are subject to such eutrophication, especially in highly polluted areas, and as such, understanding nutrient fluxes to these lakes offers insights into the varying processes governing pollutant fluxes as well as lake water quality. Here we analyse water quality data, recorded between 2006 and 2014 in 862 freshwater lakes in four geographical regions of China, to assess the input of phosphorus from human activity. We find that improvements in sanitation of both rural and urban domestic wastewater have resulted in large-scale declines in lake phosphorus concentrations in the most populated parts of China. In more sparsely populated regions, diffuse sources such as aquaculture and livestock farming offset this decline. Anthropogenic deforestation and soil erosion may also offset decreases in point sources of pollution. In the light of these regional differences, we suggest that a spatially flexible set of policies for water quality control would be beneficial for the future health of Chinese lakes.

Rapid radiation and dispersal out of the Qinghai-Tibetan Plateau of an alpine plant lineage Rhodiola (Crassulaceae).

PubMed

Zhang, Jian-Qiang; Meng, Shi-Yong; Allen, Geraldine A; Wen, Jun; Rao, Guang-Yuan

2014-08-01

Rhodiola L. (Crassulaceae) is a mid-sized plant genus consisting of about 70 species, with most species distributed on the Qinghai-Tibetan Plateau (QTP) and the adjacent areas, and several species in north-east Asia, Europe, and North America. This study explored the origin and diversification history of Rhodiola and tested the biogeographic relationships between the QTP and other regions of the Northern Hemisphere. We sequenced the nuclear ribosomal internal transcribed spacers and eight plastid DNA fragments representing 55 species of Rhodiola, and reconstructed phylogenetic relationships with maximum parsimony, maximum likelihood and Bayesian inference. Several instances of incongruence between the nuclear and the plastid data sets were revealed, which can best be explained by reticulate evolution. Species of Rhodiola and Pseudosedum form a well-supported clade sister to Phedimus. Dating analysis suggested that the origin and diversification times of this group are largely correlated with the extensive uplifts of the Qinghai-Tibetan Plateau. Ancestral state reconstruction supports the hypothesis that Rhodiola originated on the QTP, and then dispersed to other regions of the Northern Hemisphere. Our findings highlight the importance of the uplifts of the Qinghai-Tibetan Plateau in promoting species diversification and the possible role of reticulate evolution in the diversification process. Our results also suggest the biogeographic significance of QTP as the source area in alpine plant evolution in the Northern Hemisphere. Copyright © 2014 Elsevier Inc. All rights reserved.

Lake-levels, vegetation and climate in Central Asia during the Last Glacial Maximum

NASA Astrophysics Data System (ADS)

Amosov, Mikhail

2014-05-01

Central Asian region is bounded in the east corner of the Greater Khingan Range and the Loess Plateau, and to the west - the Caspian Sea. This representation of region boundaries is based on classical works of A.Humboldt and V.Obruchev. Three typical features of Central Asia nature are: climate aridity, extensive inland drainage basins with numerous lakes and mountain systems with developed glaciation. Nowadays the extensive data is accumulated about lake-levels during the Last Glacial Maximum (LGM) in Central Asia. Data compilation on 20 depressions, where lakes exist now or where they existed during LGM, shows that most of them had usually higher lake-level than at present time. This regularity could be mentioned for the biggest lakes (the Aral Sea, the Balkhash, the Ysyk-Kol etc.) and for small ones that located in the mountains (Tien Shan, Pamir and Tibet). All of these lake basins get the precipitation due to westerlies. On the other hand lakes, which are located in region's east rimland (Lake Qinghai and lakes in Inner Mongolia) and get the precipitation due to summer East Asian monsoons, do not comply with the proposed regularity. During LGM these lake-levels were lower than nowadays. Another exception is Lake Manas, its lake-level was also lowered. Lake Manas is situated at the bottom of Junggar Basin. There are many small rivers, which come from the ranges and suffer the violent fluctuation in the position of its lower channel. It is possible to assume that some of its runoff did not get to Lake Manas during LGM. Mentioned facts suggest that levels of the most Central Asian lakes were higher during LGM comparing to their current situation. However, at that period vegetation was more xerophytic than now. Pollen data confirm this information for Tibet, Pamir and Tien Shan. Climate aridization of Central Asia can be proved by data about the intensity of loess accumulation during LGM. This evidence received for the east part of region (the Loess Plateau) and

[Effects of human engineering activities on permafrost active layer and its environment in northern Qinghai-Tibetan plateau].

PubMed

Guo, Zhenggang; Wu, Qingbo; Niu, Fujun

2006-11-01

With disturbed and undisturbed belts during the construction of Qinghai-Tibet highway as test objectives, this paper studied the effects of human engineering activities on the permafrost ecosystem in northern Qinghai-Tibetan plateau. The results showed that the thickness of permafrost active layer was smaller in disturbed than in undisturbed belt, and decreased with increasing altitude in undisturbed belt while no definite pattern was observed in disturbed belt. Different vegetation types had different effects on the thickness of permafrost active layer, being decreased in the order of steppe > shrub > meadow. In the two belts, altitude was the main factor affecting the vertical distribution of soil moisture, but vegetation type was also an important affecting factor if the altitude was similar. Due to the human engineering activities, soil temperature in summer was lower in disturbed than in undisturbed belt.

Mapping spatial distribution of forest age in China

NASA Astrophysics Data System (ADS)

Zhang, Yuan; Yao, Yitong; Wang, Xuhui; Liu, Yongwen; Piao, Shilong

2017-03-01

Forest stand age is a meaningful metric, which reflects the past disturbance legacy, provides guidelines for forest management practices, and is an important factor in qualifying forest carbon cycles and carbon sequestration potential. Reliable large-scale forest stand age information with high spatial resolutions, however, is difficult to obtain. In this study, we developed a top-down method to downscale the provincial statistics of national forest inventory data into 1 km stand age map using climate data and light detection and ranging-derived forest height. We find that the distribution of forest stand age in China is highly heterogeneous across the country, with a mean value of 42.6 years old. The relatively young stand age for Chinese forests is mostly due to the large proportion of newly planted forests (0-40 years old), which are more prevailing in south China. Older forests (stand age > 60 years old) are more frequently found in east Qinghai-Tibetan Plateau and the central mountain areas of west and northeast China, where human activities are less intensive. Among the 15 forest types, forests dominated by species of Taxodiaceae, with the exception of Cunninghamia lanceolata stands, have the oldest mean stand age (136 years), whereas Pinus massoniana forests are the youngest (18 years). We further identified uncertainties associated with our forest age map, which are high in west and northeast China. Our work documents the distribution of forest stand age in China at a high resolution which is useful for carbon cycle modeling and the sustainable use of China's forest resources.

Highly Pathogenic Avian Influenza A(H5N1) Virus Struck Migratory Birds in China in 2015

PubMed Central

Bi, Yuhai; Zhang, Zhenjie; Liu, Wenjun; Yin, Yanbo; Hong, Jianmin; Li, Xiangdong; Wang, Haiming; Wong, Gary; Chen, Jianjun; Li, Yunfeng; Ru, Wendong; Gao, Ruyi; Liu, Di; Liu, Yingxia; Zhou, Boping; Gao, George F.; Shi, Weifeng; Lei, Fumin

2015-01-01

Approximately 100 migratory birds, including whooper swans and pochards, were found dead in the Sanmenxia Reservoir Area of China during January 2015. The causative agent behind this outbreak was identified as H5N1 highly pathogenic avian influenza virus (HPAIV). Genetic and phylogenetic analyses revealed that this Sanmenxia H5N1 virus was a novel reassortant, possessing a Clade 2.3.2.1c HA gene and a H9N2-derived PB2 gene. Sanmenxia Clade 2.3.2.1c-like H5N1 viruses possess the closest genetic identity to A/Alberta/01/2014 (H5N1), which recently caused a fatal respiratory infection in Canada with signs of meningoencephalitis, a highly unusual symptom with influenza infections in humans. Furthermore, this virus was shown to be highly pathogenic to both birds and mammals, and demonstrate tropism for the nervous system. Due to the geographical location of Sanmenxia, these novel H5N1 viruses also have the potential to be imported to other regions through the migration of wild birds, similar to the H5N1 outbreak amongst migratory birds in Qinghai Lake during 2005. Therefore, further investigation and monitoring is required to prevent this novel reassortant virus from becoming a new threat to public health. PMID:26259704

Ecosystem Carbon Storage in Alpine Grassland on the Qinghai Plateau

PubMed Central

Liu, Shuli; Zhang, Fawei; Du, Yangong; Guo, Xiaowei; Lin, Li; Li, Yikang; Li, Qian; Cao, Guangmin

2016-01-01

The alpine grassland ecosystem can sequester a large quantity of carbon, yet its significance remains controversial owing to large uncertainties in the relative contributions of climate factors and grazing intensity. In this study we surveyed 115 sites to measure ecosystem carbon storage (both biomass and soil) in alpine grassland over the Qinghai Plateau during the peak growing season in 2011 and 2012. Our results revealed three key findings. (1) Total biomass carbon density ranged from 0.04 for alpine steppe to 2.80 kg C m-2 for alpine meadow. Median soil organic carbon (SOC) density was estimated to be 16.43 kg C m-2 in alpine grassland. Total ecosystem carbon density varied across sites and grassland types, from 1.95 to 28.56 kg C m-2. (2) Based on the median estimate, the total carbon storage of alpine grassland on the Qinghai Plateau was 5.14 Pg, of which 94% (4.85 Pg) was soil organic carbon. (3) Overall, we found that ecosystem carbon density was affected by both climate and grazing, but to different extents. Temperature and precipitation interaction significantly affected AGB carbon density in winter pasture, BGB carbon density in alpine meadow, and SOC density in alpine steppe. On the other hand, grazing intensity affected AGB carbon density in summer pasture, SOC density in alpine meadow and ecosystem carbon density in alpine grassland. Our results indicate that grazing intensity was the primary contributing factor controlling carbon storage at the sites tested and should be the primary consideration when accurately estimating the carbon storage in alpine grassland. PMID:27494253

Ecosystem Carbon Storage in Alpine Grassland on the Qinghai Plateau.

PubMed

Liu, Shuli; Zhang, Fawei; Du, Yangong; Guo, Xiaowei; Lin, Li; Li, Yikang; Li, Qian; Cao, Guangmin

2016-01-01

The alpine grassland ecosystem can sequester a large quantity of carbon, yet its significance remains controversial owing to large uncertainties in the relative contributions of climate factors and grazing intensity. In this study we surveyed 115 sites to measure ecosystem carbon storage (both biomass and soil) in alpine grassland over the Qinghai Plateau during the peak growing season in 2011 and 2012. Our results revealed three key findings. (1) Total biomass carbon density ranged from 0.04 for alpine steppe to 2.80 kg C m-2 for alpine meadow. Median soil organic carbon (SOC) density was estimated to be 16.43 kg C m-2 in alpine grassland. Total ecosystem carbon density varied across sites and grassland types, from 1.95 to 28.56 kg C m-2. (2) Based on the median estimate, the total carbon storage of alpine grassland on the Qinghai Plateau was 5.14 Pg, of which 94% (4.85 Pg) was soil organic carbon. (3) Overall, we found that ecosystem carbon density was affected by both climate and grazing, but to different extents. Temperature and precipitation interaction significantly affected AGB carbon density in winter pasture, BGB carbon density in alpine meadow, and SOC density in alpine steppe. On the other hand, grazing intensity affected AGB carbon density in summer pasture, SOC density in alpine meadow and ecosystem carbon density in alpine grassland. Our results indicate that grazing intensity was the primary contributing factor controlling carbon storage at the sites tested and should be the primary consideration when accurately estimating the carbon storage in alpine grassland.

Green algal over cyanobacterial dominance promoted with nitrogen and phosphorus additions in a mesocosm study at Lake Taihu, China.

PubMed

Ma, Jianrong; Qin, Boqiang; Paerl, Hans W; Brookes, Justin D; Wu, Pan; Zhou, Jian; Deng, Jianming; Guo, Jinsong; Li, Zhe

2015-04-01

Enrichment of waterways with nitrogen (N) and phosphorus (P) has accelerated eutrophication and promoted cyanobacterial blooms worldwide. An understanding of whether cyanobacteria maintain their dominance under accelerated eutrophication will help predict trends and provide rational control measures. A mesocosm experiment was conducted under natural light and temperature conditions in Lake Taihu, China. It revealed that only N added to lake water promoted growth of colonial and filamentous cyanobacteria (Microcystis, Pseudoanabaena and Planktothrix) and single-cell green algae (Cosmarium, Chlorella, and Scenedesmus). Adding P alone promoted neither cyanobacteria nor green algae significantly. N plus P additions promoted cyanobacteria and green algae growth greatly. The higher growth rates of green algae vs. cyanobacteria in N plus P additions resulted in the biomass of green algae exceeding that of cyanobacteria. This indicates that further enrichment with N plus P in eutrophic water will enhance green algae over cyanobacterial dominance. However, it does not mean that eutrophication problems will cease. On the contrary, the risk will increase due to increasing total phytoplankton biomass.

Hu Huanyong: father of China's population geography.

PubMed

She, W