Frontiers of Earth Science

ISSN 2095-0195

ISSN 2095-0209(Online)

CN 11-5982/P

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, Volume 3 Issue 1

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RESEARCH ARTICLE
Immediate impacts of the Wenchuan Earthquake on the prices and productions of grain and pork products
Xiangzheng DENG, Quansheng GE, Zhigang XU, Shaoqiang WANG, Hongbo SU, Qunou JIANG, Jifu DU, Yingzhi LIN
Front Earth Sci Chin. 2009, 3 (1): 1-8.  
https://doi.org/10.1007/s11707-009-0007-7

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Based on field survey and statistical analysis, the immediate impacts of the Wenchuan Earthquake happened on May 12, 2008, are evaluated from two aspects, i.e., the influence on the prices and yields of grain and pork products in the local region and that on China. Wenchuan Earthquake, undoubtedly, has some negative effects on the local agricultural yields in Sichuan Province. It has caused immediate impacts on the grain and livestock breeding industry in the earthquake worst-hit counties. For example, due to the earthquake, the grain yields in Sichuan Province will decreased more than 0.4% and the pork productions decrease 5% at least. Thus, prices of grain and pork products are likely to rise in local mountainous areas over a short term. Our studying results that the disaster rate, the hazard rate and the complete loss rate of grain productions are 18%, 10% and 6% respectively in the earthquake worst-hit counties, while the disaster rate in the eastern plain areas even reach to 30%-49%. Even so, the results of model analysis for sample survey indicated that Wenchuan Earthquake has caused only marginal impacts on agricultural production, does not heavily hurt the stability of the prices and yields of grain and pork products at the national level. In other words, Wenchuan Earthquake had not affected the overall situation of national agricultural production. It is estimated that the reduction rate of national grain yield is as low as 0.006%, and the price changes of grain and pork products are no more than 0.5% and 2.2% respectively.

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Research paper
Sandwaves on the Southeast Vietnam Shelf recorded by high resolution seismic profiles: formation and mechanism
Viet Dung BUI, Schimanski ALEX, Stattegger KARL, Van Phach PHUNG, The Tiep NGUYEN, Tien Hai NGUYEN, Trung Thanh NGUYEN, Truong Thanh PHI
Front Earth Sci Chin. 2009, 3 (1): 9-20.  
https://doi.org/10.1007/s11707-009-0002-z

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The application of high resolution seismic data using boomer sound source has revealed a wide distribution of large-scale bedforms (sandwaves) on the Southeast Vietnam continental shelf. Bedforms that are a few meters high in wave height and hundreds of meters long in wavelength are primarily developed in the inner shelf (20-40 m) and considered to be formed under the present-day marine hydrodynamic conditions. Those bedforms developed in the deeper water (120 m) of the northernmost part of the continent can be interpreted as the relict morphological features formed during the latest sea-level lowstand of the late Pleistocene period. Two sediment transport paths have been identified on the basis of the bedform’s leeward orientation: northeast-southwest (along-shore) and north-south (cross-shore). A quantitative bottom current map is constructed from sandwave dimensions, surface sediments and measurement data. The strongest current velocities that gradually decrease toward the southwest are indicated by large sandwaves in the north (field B). Water depth, surficial sediment composition and bottom current are three factors that control the development of bedforms.

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Coastal erosion in response to wave dynamics operative in Sagar Island, Sundarban delta, India
Barendra PURKAIT
Front Earth Sci Chin. 2009, 3 (1): 21-33.  
https://doi.org/10.1007/s11707-009-0001-0

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Coastal erosion at Sagar Island of Sunderban delta, India, has been critically studied. The area is in the subtropical humid region. There are mainly three seasons viz: winter, summer and the monsoon. Different wave dynamic parameters were measured from theodolite observations with leveling staff and measuring gauges during lunar days at two sections of the western and eastern parts of the coastal zone during post-and pre-monsoons. A comparative study was made on the erosion/depositional pattern between the two sections in relation to different hydrodynamic parameters prevailing in these two sections. Plane table mapping was carried out to demarcate the different geomorphic units. The marine coastal landforms show dune ridges with intervening flats bordered by gently sloping beach on one side and a flat beach on the other side. The western part of the beach is mainly sandy; whereas the eastern part is silty and clayey with mud bank remnants. Actual field measurements indicate that the coastal dune belt has retreated to the order by about 20 m since 1985. The eastern part of the beach has lowered by about 2 m since 1985 and the western part was raised almost to the same tune. It is observed that accretion in the western and central parts of the beach took place; whereas severe erosion in the eastern part made the beach very narrow with remnants of mud banks and tree roots. Frequent embankment failures, submergence and flooding, beach erosion and siltation at jetties and navigational channels, cyclones and storm surges made this area increasingly vulnerable.

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REVIEW ARTICLE
Current and future impacts of ultraviolet radiation on the terrestrial carbon balance
W. Kolby SMITH, Wei GAO, Heidi STELTZER
Front Earth Sci Chin. 2009, 3 (1): 34-41.  
https://doi.org/10.1007/s11707-009-0011-y

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One of the most documented effects of human activity on our environment is the reduction of stratospheric ozone resulting in an increase of biologically harmful ultraviolet (UV) radiation. In a less predictable manner, UV radiation incident at the surface of the earth is expected to be further modified in the future as a result of altered cloud condition, atmospheric aerosol concentration, and snow cover. Although UV radiation comprises only a small fraction of the total solar radiation that is incident at the earth’s surface, it has the greatest energy per unit wavelength and, thus, the greatest potential to damage the biosphere. Recent investigations have highlighted numerous ways that UV radiation could potentially affect a variety of ecological processes, including nutrient cycling and the terrestrial carbon cycle. The objectives of the following literature review are to summarize and synthesize the available information relevant to the effects of UV radiation and other climate change factors on the terrestrial carbon balance in an effort to highlight current gaps in knowledge and future research directions for UV radiation research.

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RESEARCH ARTICLE
Rapid warming in mid-latitude central Asia for the past 100 years
Fahu CHEN, Jinsong WANG, Liya JIN, Qiang ZHANG, Jing LI, Jianhui CHEN
Front Earth Sci Chin. 2009, 3 (1): 42-50.  
https://doi.org/10.1007/s11707-009-0013-9

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Surface air temperature variations during the last 100 years (1901-2003) in mid-latitude central Asia were analyzed using Empirical Orthogonal Functions (EOFs). The results suggest that temperature variations in four major sub-regions, i.e. the eastern monsoonal area, central Asia, the Mongolian Plateau and the Tarim Basin, respectively, are coherent and characterized by a striking warming trend during the last 100 years. The annual mean temperature increasing rates at each sub-region (representative station) are 0.19°C per decade, 0.16°C per decade, 0.23°C per decade and 0.15°C per decade, respectively. The average annual mean temperature increasing rate of the four sub-regions is 0.18°C per decade, with a greater increasing rate in winter (0.21°C per decade). In Asian mid-latitude areas, surface air temperature increased relatively slowly from the 1900s to 1970s, and it has increased rapidly since 1970s. This pattern of temperature variation differs from that in the other areas of China. Notably, there was no obvious warming between the 1920s and 1940s, with temperature fluctuating between warming and cooling trends (e.g. 1920s, 1940s, 1960s, 1980s, 1990s). However, the warming trends are of a greater magnitude and their durations are longer than that of the cooling periods, which leads to an overall warming. The amplitude of temperature variations in the study region is also larger than that in eastern China during different periods.

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Coincident negative shifts in sulfur and carbon isotope compositions prior to the end-Permian mass extinction at Shangsi Section of Guangyuan, South China
Pengwei LI, Junhua HUANG, Min CHEN, Xiao BAI
Front Earth Sci Chin. 2009, 3 (1): 51-56.  
https://doi.org/10.1007/s11707-009-0018-4

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Sulfur isotope composition of carbonate-associated sulfate (δ34SCAS) and carbon isotope composition of carbonate (δ13Ccarb) were jointly investigated on the Late Permian rocks at Shangsi Section, Guanyuan, Northeast Sichuan, South China. Both δ34SCAS and δ13Ccarb show gradual decline trends in Late Permian strata, inferring the occurrence of the long-term variation of marine environmental conditions. Associated with the long-term variation are the two coincident negative shifts in δ34SCAS and δ13Ccarb, with one occurring at the boundary between Middle Permian Maokou Formation and Late Permian Wujiaping Formation and another at Middle Dalong Formation. Of significance is the second shift which clearly predates the regression and the biotic crisis at the end of Permian at Shangsi Section, providing evidence that a catastrophic event occurred prior to the biotic crisis. The frequent volcanisms indicated by the volcanic rocks or fragments, and the upwelling are proposed to cause the second negative excursion. An abrupt extreme negative δ34SCAS (ca. -20‰) associated with a low relative concentration of CAS and total organic carbon without large change in δ13Ccarb is found at the end of the second shift, which might arise from the short-term oxygenation of bottom waters and sediments that resulted from the abrupt sea level drop.

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REVIEW ARTICLE
A historical review on the roles of science and politics in addressing global environmental issues
Peter USHER, Qian YE
Front Earth Sci Chin. 2009, 3 (1): 57-62.  
https://doi.org/10.1007/s11707-009-0020-x

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Based on a historical review of the so-called Ozone crisis in the late 1970s and global climate changes since the 1980s, this paper examines the role of sciences and policies in the international community in dealing with the global environmental issues. Lessons show that a multi-discipline, multi-organizational and multi-national UN agency which remains relevant, assisting rather than guiding the process of climate negotiations is important.

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RESEARCH ARTICLE
Environmental geochemistry of high arsenic groundwater at western Hetao plain, Inner Mongolia
Jun HE, Teng MA, Yamin DENG, Hui YANG, Yanxin WANG
Front Earth Sci Chin. 2009, 3 (1): 63-72.  
https://doi.org/10.1007/s11707-009-0004-x

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Environmental geochemistry of high arsenic groundwater at Hetao plain was studied on the basis of geochemical survey of the groundwater and a core sediment. Arsenic concentration in groundwater samples varies from 76 to 1093 μg/L. The high arsenic groundwater mostly appears to be weakly alkaline. The concentrations of NO3- and SO42- are relatively low, while the concentrations of DOC, NH4+, dissolved Fe and sulfide are relatively great. Analysis of arsenic speciation in 21 samples shows that arsenic is present in the solution predominantly as As(III), while particulate arsenic constitutes about 10% of the total arsenic. Methane is detected in five samples with the greatest content being 5107 μg/L. The shallow aquifer in Hangjinhouqi of western Hetao plain is of strongly reducing condition. The arsenic content in 23 core sediment samples varies from 7.7 to 34.6 mg/kg, with great value in clay and mild clay layer. The obvious positive relationship in content between Fe2O3, Mn, Sb, B, V and As indicates that the distribution of arsenic in the sediments may be related to Fe and Mn oxides, and the mobilization of Sb, B and V may be affected by similar geochemical processes as that of As.

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Distribution of phthalate esters in the groundwater of Jianghan plain, Hubei, China
Dan ZHANG, Hui LIU, Ying LIANG, Cheng WANG, Hecheng LIANG, Hesheng CAI
Front Earth Sci Chin. 2009, 3 (1): 73-79.  
https://doi.org/10.1007/s11707-009-0017-5

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Samples of groundwater were collected from 17 sites in the Jianghan plain in July 2007. Sixteen phthalate esters (PAEs) were detected in samples collected by using solid-phase extraction (SPE)-gas chromatography (GC). The results show that there were one or several PAEs in all the samples, and the concentrations of total PAEs ranged from 80.12 to 1882.18 ng/L. Four PAEs, i.e. di-iso-butyl phthalate (DIBP), di-n-butyl phthalate (DBP), bis (2-ethoxyethyl) phthalate (BEEP) and di (2-ethylhexyl) phthalate DEHP) were the dominant species. Among these, DIBP, DBP and DEHP concentrations were closely related to the water supply from the Yangtze River, Hanjiang River and Honghu Lake. However, the distribution of BEEP was irregular, which may be due to the application of some kind of products containing BEEP in the related areas. PAE distribution was irrelevant to the electrical conductivity and sample depth.

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Abundance and diversity of snow bacteria in two glaciers at the Tibetan Plateau
Yongqin LIU, Tandong YAO, Nianzhi JIAO, Shichang KANG, Yonghui ZENG, Xiaobo LIU
Front Earth Sci Chin. 2009, 3 (1): 80-90.  
https://doi.org/10.1007/s11707-009-0016-6

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Snow bacterial abundance and diversity at the Guoqu Glacier and the East Rongbuk Glacier located in the central and southern Tibetan Pateau were investigated using a 16S rRNA gene clone library and flow cytometry approach. Bacterial abundance was observed to show seasonal variation, with different patterns, at the two glaciers. High bacterial abundance occurs during the monsoon season at the East Rongbuk Glacier and during the non-monsoon season at the Guoqu Glacier. Seasonal variation in abundance is caused by the snow bacterial growth at the East Rongbuk Glacier, but by bacterial input from the dust at the Guoqu Glacier. Under the influence of various atmospheric circulations and temperature, bacterial diversity varies seasonally at different degrees. Seasonal variation in bacterial diversity is more distinct at the Guoqu Glacier than at the East Rongbuk Glacier. Bacterial diversity at the two glaciers exhibits different responses to various environmental conditions. More bacteria at the Guoqu Glacier are connected with those from a soil environment, while more bacteria affiliated with a marine environment occur at the East Rongbuk Glacier.

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Distributions of phospholipid and glycolipid fatty acids in two strains of different functional Erythrobacter sp. isolated from South China Sea
Huan YANG, Xiangru MA1, Qiang LI, Nianzhi JIAO, Shucheng XIE
Front Earth Sci Chin. 2009, 3 (1): 91-99.  
https://doi.org/10.1007/s11707-009-0009-5

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The comparison of the fatty acids between aerobic anoxygenic phototrophic bacteria (AAPB) and their phylogenetic relatives has been a fascinating but yet enigmatic topic, enhancing our understanding of physiological variations between these evolutionarily related microorganisms. Two strains of marine bacteria, both phylogenetically falling into Erythrobacter sp., were isolated from the South China Sea, and demonstrated, respectively, to be an aerobic anoxygenic phototrophic bacteria (AAPB) (JL475) which is capable of anoxygenic photosynthesis via BChl a, and an obligate heterotroph (JL316) with a lack of BChl a, on the basis of phylogenetic analysis and pure culture cultivation. Phospholipid fatty acids (PLFA) and glycolipid fatty acids (GLFA) of the two strains were extracted and analyzed by gas chromatography-mass spectrometry. The PLFA in JL475 AAPB are characterized by C18∶1, C18∶2ω7,13 and C18∶0, with the C18∶2ω7,13 being a specific compound for AAPB and in particular for Erythrobacter longus and some of its phylogenetically closely related relatives. The JL316 strain is characterized in PLFA by the presence of C18∶1, C16∶1 and C16∶0, and in particular C17∶1. GLFA do not show any discrimination between the two strains. Four α,ω-dicarboxylic acids, including 1,8-octanedioic acid, 1,9-nonanedioic acid, 1,10-decanedioic acid and 1,11-undecanedioic acid, are present only in JL316 GLFA, presumably derived from metabolic products. C14—C16 2-hydroxy fatty acids were found in the two strains, probably assuming a similar function of their LPS in outer membranes.

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Short sequence effect of ancient DNA on mammoth phylogenetic analyses
Guilian SHENG, Lianjuan WU, Xindong HOU, Junxia YUAN, Shenghong CHENG, Bojian ZHONG, Xulong LAI
Front Earth Sci Chin. 2009, 3 (1): 100-106.  
https://doi.org/10.1007/s11707-009-0010-z

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The evolution of Elephantidae has been intensively studied in the past few years, especially after 2006. The molecular approaches have made great contribution to the assumption that the extinct woolly mammoth has a close relationship with the Asian elephant instead of the African elephant. In this study, partial ancient DNA sequences of cytochrome b (cyt b) gene in mitochondrial genome were successfully retrieved from Late Pleistocene Mammuthus primigenius bones collected from Heilongjiang Province in Northeast China. Both the partial and complete homologous cyt b gene sequences and the whole mitochondrial genome sequences extracted from GenBank were aligned and used as datasets for phylogenetic analyses. All of the phylogenetic trees, based on either the partial or the complete cyt b gene, reject the relationship constructed by the whole mitochondrial genome, showing the occurrence of an effect of sequence length of cyt b gene on mammoth phylogenetic analyses.

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Stable carbon isotope characteristics of different plant species and surface soil in arid regions
Jianying MA, Wei SUN, Huiwen ZHANG, Dunsheng XIA, Chengbang AN, Fahu CHEN
Front Earth Sci Chin. 2009, 3 (1): 107-111.  
https://doi.org/10.1007/s11707-009-0015-7

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The stable carbon isotope composition in surface soil organic matter (δ13Csoil) contains integrative information on the carbon isotope composition of the standing terrestrial plants (δ13Cleaf). In order to obtain valuable vegetation information from the δ13C of terrestrial sediment, it is necessary to understand the relationship between the δ13C value in modern surface soil and the standing vegetation. In this paper, we studied the δ13C value in modern surface soil organic matter and standing vegetation in arid areas in China, Australia and the United States. The isotopic discrepancy between δ13Csoil and δ13Cleaf of the standing dominant vegetation was examined in those different arid regions. The results show that the δ13Csoil values were consistently enriched compared to the δ13Cleaf. The δ13Cleaf values were positively correlated with δ13Csoil, which suggests that the interference of microorganisms and hydrophytes on the isotopic composition of surface soil organic matter during soil organic matter formation could be ignored in arid regions. The averaged discrepancy between δ13Csoil and δ13Cleaf is about 1.71‰ in Tamarix L. in the Tarim Basin in China, 1.50‰ in Eucalytus near Orange in Australia and 1.22‰ in Artemisia in Saratoga in the United States, which are different from the results of other studies. The results indicate that the discrepancies in the δ13C value between surface soil organic matter and standing vegetation were highly influenced by the differences in geophysical location and the dominant species of the studied ecosystems. We suggest that caution should be taken when organic matter δ13C in terrestrial sediment is used to extract paleovegetation information (C3/C4 vegetation composition), as the δ13C in soil organic matter is not only determined by the ratio of C3/C4 species, but also profoundly affected by climate change induced variation in the δ13C in dominant species.

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Quantify the landscape effect and environmental sustainability of rural region planning at town scale near metropolis
Shiliang LIU, Yuhong DONG, Minxia WEN, Bin CHEN
Front Earth Sci Chin. 2009, 3 (1): 112-117.  
https://doi.org/10.1007/s11707-009-0006-8

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The urban fringe, which can be seen as a special form of regional ecosystem with a spatial transition from urban to rural areas, has strong heterogeneity and is a typical ecologically sensitive area. The expansion of cities and the landscape effect of the changes have attracted wide attention. The primary aim of this study is to obtain an understanding of the spatial patterns of landscape conversion and the corresponding environmental sustainability. With the help of GIS and Fragstats software, the changes of landscape patterns before and after town planning were compared in An-Ding town of Beijing, of which the sustainability was also revealed based on the ecological footprint using social and economic statistic data. The results showed that the landscape pattern changed greatly during its conversion from several villages to a small town and the landscape fragmentation increased due to road construction. Meanwhile, human disturbance increased with the constructed land extension. For the gap between the ecological footprint and the biological capacity, An-Ding town ran an ecological deficit at that period, which means it was unsustainable. However, the environmental sustainability decreased after planning due to the degraded green land and forest. The results suggested that ecological management should be strengthened during the town planning period.

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Estimation of winter wheat biomass based on remote sensing data at various spatial and spectral resolutions
Yansong BAO, Wei GAO, Zhiqiang GAO
Front Earth Sci Chin. 2009, 3 (1): 118-128.  
https://doi.org/10.1007/s11707-009-0012-x

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Biomass can indicate plant growth status, so it is an important index for plant growth monitoring. This paper focused on the methodology of estimating the winter wheat biomass based on hyperspectral field data, including the LANDSAT TM and EOS MODIS images. In order to develop the method of retrieving the wheat biomass from remote sensed data, routine field measurements were initiated during periods when the LANDSAT satellite passed over the study region. In the course of the experiment, five LANDSAT TM images were acquired respectively at early erecting stage, jointing stage, earring stage, flowering stage and grain-filling stage of the winter wheat, and the wheat biomass was measured at each stage. Based on the TM and MODIS images, spectral indices such as NDVI, RDVI, EVI, MSAVI, SIPI and NDWI were calculated. At the same time, the hyperspectral field data was used to compute the normalized difference in spectral indices, red-edge parameters, spectral absorption, and reflection feature parameters. Then the correlation coefficients between the wheat biomass and spectral parameters of the experiment sites were computed. According to the correlation coefficients, the optimal spectral parameters for estimating the wheat biomass were determined. The best-fitting method was employed to build the relationship models between the wheat biomass and the optimal spectral parameters. Finally, the models were used to estimate the wheat biomass based on the TM and MODIS data. The maximum RMSE of estimated biomass was 66.403 g/m2.

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15 articles