			Home About us Contact

Yangtze River Delta (yangtze + river_delta)

Distribution by Scientific Domains

Earth and Environmental Science	50%

Selected Abstracts

Distribution of polycyclic aromatic hydrocarbons in particle-size separates and density fractions of typical agricultural soils in the Yangtze River Delta, east China

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 6 2008
J. Z. Ni
Summary Soil organic matter can be divided into different organic carbon (C) pools with different turnover rates. The organic pollutants in soils associated with these organic C pools may have different bioavailability and environmental risks during the decomposition of soil organic matter. We studied the distribution patterns of 15 USEPA priority polycyclic aromatic hydrocarbons (PAHs) in different particle-size separates (clay, fine silt, coarse silt, fine sand and coarse sand) and density fractions (light and heavy fractions) of nine agricultural topsoils (0,20 cm depth) from a contaminated area in the Yangtze River Delta region of east China. There was a decreasing trend in PAH concentration in particle-size separates with decreasing particle size. However, the different particle-size separates had similar PAH composition. The concentration of PAHs in the light fraction ranged from 13 037 to 107 299 ,g kg,1, far higher than in the heavy fraction, which ranged from 222 to 298 ,g kg,1. Although the light fraction accounted for only 0.4,2.3% of the soils, it was associated with 31.5,69.5% of soil PAHs. The organic matter in coarse silt had the strongest capacity for enrichment with PAHs. Combining the distributions of PAHs and the turnover rates of organic matter in different soil fractions, the environmental risks of PAH-polluted soils may be due mainly to the PAHs associated with sand and the light fraction. [source]

Port competition in the Yangtze River Delta

ASIA PACIFIC VIEWPOINT, Issue 3 2007
Claude Comtois
Abstract: This paper canvasses the port development of the Yangtze River Delta. Initially, we consider changes in container trade in the region since the 1990s. Competition between the ports of Ningbo and Shanghai are studied by measuring the overlapping hinterland of container distribution for Zhejiang province. We then analyse the strategies pursued by international carriers and terminal operators to secure success in this increasingly competitive environment. [source]

Analysis of the Geomorphology and Environmental Geological Problems of Huzhou on the Yangtze River Delta

ACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 3 2004
JIANG Yuehua
Abstract, Geomorphically, Huzhou, which is on the Yangtze River delta is characterized mainly by plains, with small hills. This paper presents a detailed analysis of the environmental geological hazards both natural and those incurred by human activities in different morphologic units. The authors point out that most of the regional environmental geological problems in the natural geologic-morphologic conditions, such as crustal stability, foundation of soft soil, soil waterlogging and soil erosion, have insignificant effects to the society, or related countermeasures of prevention and control have been adopted. But environmental geological problems incurred by human being's economic activities become more and more severe, for example, water and soil pollution and land subsidence in plain areas resulting from overexploitation of groundwater, and landslides, karst collapses and water and soil loss etc. caused by quarrying in hilly areas. [source]

Nitrogen-regulated effects of free-air CO2 enrichment on methane emissions from paddy rice fields

GLOBAL CHANGE BIOLOGY, Issue 9 2006
XUNHUA ZHENG
Abstract Using the free-air CO2 enrichment (FACE) techniques, we carried out a 3-year mono-factorial experiment in temperate paddy rice fields of Japan (1998,2000) and a 3-year multifactorial experiment in subtropical paddy rice fields in the Yangtze River delta in China (2001,2003), to investigate the methane (CH4) emissions in response to an elevated atmospheric CO2 concentration (200±40 mmol mol,1 higher than that in the ambient atmosphere). No significant effect of the elevated CO2 upon seasonal accumulative CH4 emissions was observed in the first rice season, but significant stimulatory effects (CH4 increase ranging from 38% to 188%, with a mean of 88%) were observed in the second and third rice seasons in the fields with or without organic matter addition. The stimulatory effects of the elevated CO2 upon seasonal accumulative CH4 emissions were negatively correlated with the addition rates of decomposable organic carbon (P<0.05), but positively with the rates of nitrogen fertilizers applied in either the current rice season (P<0.05) or the whole year (P<0.01). Six mechanisms were proposed to explain collectively the observations. Soil nitrogen availability was identified as an important regulator. The effect of soil nitrogen availability on the observed relation between elevated CO2 and CH4 emission can be explained by (a) modifying the C/N ratio of the plant residues formed in the previous growing season(s); (b) changing the inhibitory effect of high C/N ratio on plant residue decomposition in the current growing season; and (c) altering the stimulatory effects of CO2 enrichment upon plant growth, as well as nitrogen uptake in the current growing season. This study implies that the concurrent enrichment of reactive nitrogen in the global ecosystems may accelerate the increase of atmospheric methane by initiating a stimulatory effect of the ongoing dramatic atmospheric CO2 enrichment upon methane emissions from nitrogen-poor paddy rice ecosystems and further amplifying the existing stimulatory effect in nitrogen-rich paddy rice ecosystems. [source]