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Zhang J.,Beijing Normal University | Zeng W.,Beijing Normal University | Wang J.,Chinese Research Academy of Environmental Sciences | Yang F.,Yunnan Institute of Environmental Science | Jiang H.,Chinese Research Academy of Environmental Sciences
Journal of Cleaner Production | Year: 2015

As the largest energy consumer and CO2 emitting country, the Chinese government is committing to a low-carbon economy. It is meaningful and contributes to evaluate and analyze the low-carbon economy efficiency (LCEE) of China. A Super-slack-based measure (Super-SBM) model with undesirable outputs, as combined with the Malmquist productivity index, is proposed to measure the LCEE and the dynamic low-carbon economy efficiency (DLCEE) of 30 provinces in mainland China from 2005 to 2012. The Theil index is also used to measure the rationalization level of industrial structure (RLIS) for discussing the improvements to the LCEE in China. The results indicate that the proposed undesirable outputs Super-SBM model can effectively rank the SBM-effi{ligature}cient provinces. China's regional economic development does not follow a low-carbon pattern, with an average LCEE of 0.517. As a whole, the China's economic development is gradually following a low-carbon development pattern with an annual LCEE improvement of 4.5%. The RLIS of China is also gradually changing better, as well. Through a comparative analysis of the LCEE and RLIS, the 30 provinces are divided into three sub-areas, and relevant suggestions are presented for improving the LCEE of different sub-areas in the future. © 2015 Elsevier Ltd.

Ma X.,CAS Kunming Institute of Botany | Ma X.,World Agroforestry Center | Ma X.,Yunnan Institute of Environmental science | Lu X.X.,National University of Singapore | And 4 more authors.
Hydrology and Earth System Sciences | Year: 2014

Suspended sediment transport in rivers is controlled by terrain, climate, and human activities. These variables affect hillslope and riverbank erosion at the source, transport velocities and sedimentation opportunities in the river channel, and trapping in reservoirs. The relative importance of those factors varies by context, but the specific attribution to sediment transfer is important for policymaking, and has wide implications on watershed management. In our research, we analyzed data from the Kejie watershed in the upper Salween River (Yunnan Province, China), where a combination of land cover change (reforestation, as well as soil and water conservation measures) and river channel engineering (sand mining and check dam construction) interact with a changing climate. Records (1971-2010) of river flow and suspended sediment loads were combined with five land-use maps from 1974, 1991, 2001, 2006 and 2009. Average annual sediment yield decreased from 13.7 tha-1 yr -1 to 8.3 tha-1 yr-1 between the period 1971-1985 and the period 1986-2010. A distributed hydrological model (Soil and Water Assessment Tools, SWAT) was set up to simulate the sediment sourcing and transport process. By recombining land-use and climate data for the two periods in model scenarios, the contribution of these two factors could be assessed with engineering effects derived from residual measured minus modeled transport. Overall, we found that 47.8% of the decrease was due to land-use and land cover change, 19.8% to climate change, resulting in a milder rainfall regime, 26.1% to watershed engineering measures, and the remaining 6.3% was due to the simulation percent bias. Moreover, mean annual suspended sediment yield decreased drastically with the increase of forest cover, making diverse forest cover one of the most effective ecosystems to control erosion. For consideration of stakeholders and policymakers, we also discuss at length the modeling uncertainty and implications for future soil and water conservation initiatives in China. © 2014 Author(s).

PubMed | University of Victoria, East China Normal University, Vietnam Academy of Science and Technology, Montclair State University and Yunnan Institute of Environmental Science
Type: Journal Article | Journal: Marine pollution bulletin | Year: 2016

Surface sediment samples were collected from upstream down to the subaqueous delta of the Red River in Vietnam to assess heavy metal pollution. Sediment Cr and V concentrations are strongly correlated with Al, Fe, Mn and total organic carbon concentrations, as well as particle size, suggesting that these two metals are derived primarily from natural sources and enriched in the fine fraction of sediments. In contrast, Cu, Cd, Pb, Ni and Zn concentrations show weaker correlations with particle size, with very high concentrations observed at several sites in the upper reach of the river, pointing to anthropogenic input as a possible source of these heavy metals. Enrichment factors (EF) of Cu, Cd, Pb, Ni and Zn suggest that heavy metal pollution is present in sediments with significantly high values in the upstream. The data analysis indicates that Cd, Cu and Pb are the dominant pollutants in the Red River, with their concentrations reaching moderate to serious pollution levels.

PubMed | Queen's University, Yunnan Normal University, Yunnan Institute of Environmental science and Fujian Normal University
Type: | Journal: Scientific reports | Year: 2015

Heavy metal pollution is now widely recognized to pose severe health and environmental threats, yet much of what is known concerning its adverse impacts on ecosystem health is derived from short-term ecotoxicological studies. Due to the frequent absence of long-term monitoring data, little is known of the long-tem ecological consequences of pollutants such as arsenic. Here, our dated sediment records from two contaminated lakes in China faithfully document a 13.9 and 21.4-fold increase of total arsenic relative to pre-1950 background levels. Concurrently, coherent responses in keystone biota signal pronounced ecosystem changes, with a >10-fold loss in crustacean zooplankton (important herbivores in the food webs of these lake systems) and a >5-fold increase in a highly metal-tolerant alga. Such fundamental ecological changes will cascade through the ecosystem, causing potentially catastrophic consequences for ecosystem services in contaminated regions.

Cui L.,South China Agricultural University | Ouyang Y.,St. Johns River Water Management District | Lou Q.,South China Agricultural University | Yang F.,Yunnan Institute of Environmental Science | And 3 more authors.
Ecological Engineering | Year: 2010

Constructed wetlands are becoming increasingly popular worldwide for removing contaminants from domestic wastewater. This study investigated the removal efficiency of nitrogen (N) and phosphorus (P) from wastewater with the simulated vertical-flow constructed wetlands (VFCWs) under three different substrates (i.e., BFAS or blast furnace artificial slag, CBAS or coal burn artificial slag, and MSAS or midsized sand artificial slag), hydraulic loading rates (i.e., 7, 14, and 21 cm d-1), and wetland operational periods (0.5, 1, and 2 years) as well as with and without planting Canna indica L. The wastewater was collected from the campus of South China Agricultural University, Guangzhou, China. Results show that the percent removal of total P (TP) and ammonium N (NH4 +-N) by the substrates was BFAS > CBAS > MSAS due to the high contents of Ca and Al in substrate BFAS. In contrast, the percent removal of total N (TN) by the substrates was CBAS > MSAS > BFAS due to the complicated nitrification/denitrification processes. The percent removal of nutrients by all of the substrates was TP > NH4 +-N > TN. About 10% more TN was removed from the wastewater after planting Canna indica L. A lower hydraulic loading rate or longer hydraulic retention time (HRT) resulted in a higher removal of TP, NH4 +-N, and TN because of more contacts and interactions among nutrients, substrates, and roots under the longer HRT. Removal of NO3 -N from the simulated VFCWs is a complex process. A high concentration of NO3 -N in the effluent was observed under the high hydraulic loading rate because more NH4 +-N and oxygen were available for nitrification and a shorter HRT was unfavorable for denitrification. In general, a longer operational period had a highest removal rate for nutrients in the VFCWs. © 2010 Elsevier B.V. All rights reserved.

Zhang X.-Y.,Yunnan Institute of Environmental Science | Chen Y.-H.,Yunnan Institute of Environmental Science | Xu Y.,Kunming University of Science and Technology
Resources, Environment and Engineering - 2nd Technical Congress on Resources, Environment and Engineering, CREE 2015 | Year: 2016

Kunming is menaced by raw water shortage due to serious drought for several years. The hydraulic model is applied to multiple water reduction dispatch schemes comparison in order to resolve water shortage threat and provide basic supply service at the same time. The trials were carried out in a normal scheme, district turns water supply, and period water reduction by monitoring the flow and pressure of network. The research showed, period water reduction scheme is the best plan for considering the elements of water saving, pressure and flow stability, operability, and supply service guarantee. The scheme made a significant effort when it was implemented, the error of simulated pressure from real time pressure was neglectable and the result was high correlative. The successful case was a good reference for other regions facing raw water shortage crisis. The hydraulic model is worked as a fundamental tool for water supply dispatch supporting. © 2016 Taylor & Francis Group, London.

Zhao J.,CAS Xishuangbanna Tropical Botanical Garden | Zhao J.,University of Chinese Academy of Sciences | Zhang Y.,CAS Xishuangbanna Tropical Botanical Garden | Song F.,Yunnan Institute of Environmental Science | And 2 more authors.
Journal of Tropical Ecology | Year: 2013

The phenology of temperate plants is vulnerable to climate change. Yet, the phenological responses of tropical plants to climate change are still unclear. In this study, temporal trends (1973-1999) of four phenological events (budburst, growing season, flowering and flowering duration) were studied among 21 plant species in Xishuangbanna Tropical Botanical Garden (south-western China). Fourteen species (67%) showed significant phenological trends during the study period. Seven species (33%) presented delaying trends in budburst (average 1.4 d y-1) and such trend was more likely to be presented in those that started budburst earlier in the dry season. Four species (19%) showed trends of extension in growing season (average of 3.5 d y-1). These vegetative events appeared to be mainly influenced by increasing temperature. Rainfall showed little effects directly, however, the effects of temperature seemed to largely depend on the moisture condition. Flowering duration of five species (24%) was shortened by average 2.1 d y-1 which was most likely to be the result of the decline in sunshine duration during the rainy season. Our results suggest that the phenology of tropical plants has changed significantly in response to the regional climate change but these reactions are somewhat different from those of temperate plants. Copyright © 2013 Cambridge University Press.

Ma X.,Yunnan Institute of Environmental Science | Ma X.,CAS Kunming Institute of Botany | Xu J.,CAS Kunming Institute of Botany | Xu J.,World Agroforestry Center | van Noordwijk M.,World Agroforestry Center Southeast Asia
Hydrological Processes | Year: 2010

Global climate change will likely increase temperature and variation in precipitation in the Himalayas, modifying both supply of and demand for water. This study assesses combined impacts of land-cover and climate changes on hydrological processes and a rainfall-to-streamflow buffer indicator of watershed function using the Soil Water Assessment Tool (SWAT) in Kejie watershed in the eastern Himalayas. The Hadley Centre Coupled Model Version 3 (HadCM3) was used for two Intergovernmental Panel on Climate Change (IPCC) emission scenarios (A2 and B2), for 2010-2099. Four land-cover change scenarios increase forest, grassland, crops, or urban land use, respectively, reducing degraded land. The SWAT model predicted that downstream water resources will decrease in the short term but increase in the long term. Afforestation and expansion in cropland will probably increase actual evapotranspiration (ET) and reduce annual streamflow but will also, through increased infiltration, reduce the overland flow component of streamflow and increase groundwater release. An expansion in grassland will decrease actual ET, increase annual streamflow and groundwater release, while decreasing overland flow. Urbanization will result in increases in streamflow and overland flow and reductions in groundwater release and actual ET. Land-cover change dominated over effects on streamflow of climate change in the short and middle terms. The predicted changes in buffer indicator for land-use plus climate-change scenarios reach up to 50% of the current (and future) range of inter-annual variability. Copyright © 2010 John Wiley & Sons, Ltd.

Lu J.,CAS Wuhan Botanical Garden | Lu J.,University of Chinese Academy of Sciences | Zhou H.,Yunnan Institute of Environmental Science | Tian G.,CAS Wuhan Botanical Garden | Liu G.,CAS Wuhan Botanical Garden
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2011

Nutrient limitation (mostly nitrogen or phosphorus) s thought be a driving force in ecosystem development. It was hypothesized that the N:P ratio of the vegetation directly reflects the nature of nutrient limitation. At vegetation level, N:P ratios < 14 and > 16 often correspond to N- and P-limited biomass production. The study on nitrogen (N) and phosphorus (P) contents of plants thus may greatly increase our limited knowledge of the nature of nutrient limitation and also provide guidance for ecological restoration. This paper investigated N and P contents of 44 wetland plants from the Lake Erhai basin. The results showed that the mean contents of N and P were 15. 7 mg/g and 3. 3 mg/g dry weight, and ranged from 6.4 to 34. 3 mg/g for N and 1.4 to 6. 5 mg/g for P, respectively, and they were markedly higher than those from other regions. The N:P ratio ranged from 2.2 to 9. 5, indicating that N was the limiting factor in the Lake Erhai basin. There was a significant difference in N and P contents between above- and belowground parts in plants. The mean N content (16. 7 mg/g) and P content (3.6 mg/g) of aboveground part were significantly higher than those (N content of 9. 8 mg/g and P content of 3. 1 mg/g) of belowground part. There was a significant difference in N and P contents among functional groups. Submerged species exhibited significantly higher N contents (17.7 mg/g) than the emergent species (12. 1 mg/g) and free-floating/floating-leaved species (13.4 mg/g), while mud-flat species had significantly higher P contents (3.6 mg/g) than submerged species (2. 6mg/g). Overall, the biomass, and N and P contents of above-ground tissue respectively accounted for 72%, 82% and 75% of those in the whole plant, which suggested that harvesting of above-ground tissue could effectively remove N and P from wetland ecosystem.

Cui L.-H.,South China Agricultural University | Zhu X.-Z.,South China Agricultural University | Ouyang Y.,St. Johns River Water Management District | Chen Y.,South China Agricultural University | Yang F.-L.,Yunnan Institute of Environmental Science
International Journal of Phytoremediation | Year: 2011

Vertical-flow constructed wetland (VFCW) is an effective alternative for removal of nutrients, heavy metals, and organic pollutants from wastewaters. This study investigated the uptake and removal of total phosphorus (TP) by Cyperus alternifolius from domestic wastewaters in the simulated VFCWs. The total of eight simulated VFCW treatments, including two different substrates, two different wet-to-dry ratios, and with and without C. alternifolius species (2 × 2 × 2 = 8), were utilized for an operation period of two years in this study. Results show that about 1.1 to 1.4 times more TP was removed from the influent with the presence of C. alternifolius as compared to without this plant species. A linear correlation existed between the aboveground biomass and its TP content. An increase in total biomass by 1000 g would result in an increase in TP accumulation in the aboveground biomass by 4.9g. Large amounts of TP were removed by the substrate adsorption as compared to those by the aboveground biomass. Results suggest that, although substrate adsorption played a major role in TP removal, C. alternifolius uptake was an alternative pathway for further removal of TP from wastewaters in the VFCWs. © Taylor &Francis Group, LLC.

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