Detrimental effects of reduced seawater pH on the early development of the Pacific abalone

The hatching process of the Pacific abalone Haliotis discus hannai was prolonged at a pH of 7.6 and pH 7.3, and the embryonic developmental success was reduced. The hatching rate at pH 7.3 was significantly (10.8%) lower than that of the control (pH 8.2). The malformation rates at pH 7.9 and pH 8.2 were less than 20% but were 53.8% and 77.3% at pH 7.6 and pH 7.3, respectively. When newly hatched larvae were incubated for 48 h at pH 7.3, only 2.7% of the larvae settled, while more than 70% of the larvae completed settlement in the other three pH treatments. However, most 24 h old larvae could complete metamorphosis in all four pH treatments. Overall, a 0.3-unit reduction in water pH will produce no negative effect on the early development of the Pacific abalone, but further reduction in pH to the values predicted for seawater by the end of this century will have strong detrimental effects.     

Ecological Risk Assessment of Benzo[a]pyrene in Yellow River Delta

Ecological risk assessment is of great significance to promoting the rational management effectively for the oil‐polluted areas. A comprehensive evaluation method of ecological risk, including probabilistic risk assessment and regional ecological risk assessment, is developed through employing the contaminant benzo[a]pyrene as an indicator to assess ecological risk of five oil mining plots, respectively in Yellow River Delta. In this study, firstly we evaluate the ecological risk probability of five oil mining plots using overlapping area of probabilistic curves, and the results show that local ecological risk varies between the maximum 0.4 and the minimum 0.01. Then we overlay boundaries of five administrative divisions in Yellow River Delta and the spatial distribution patterns of ecosystems to generate new risk receptor plaques, and calculate the integrated value of 30 specifically classified plaques for comprehensive evaluation of ecological risk. The results, fluctuating within the range of 0.00005 and 0.25, indicate that local government should be vigilant to ecological risk of benzo[a]pyrene to some extent, although the current situation is not severe in whole.     

Geology,geochemistry, and geochronology of the Miaowan ophiolite,Yangtze craton: Implications for South China's amalgamation history with the Rodinian supercontinent

We report the presence of a Grenvillian ophiolite on the northern margin of the Yangtze craton, drastically changing current ideas about South China's role in plate reconstructions of the Rodinia supercontinent. Strongly deformed amphibolites that locally show relict pillow lavas, isotropic and layered metagabbro, diabase dikes, serpentinized dunite and harzburgite with podiform chromite are dated at circa 1100–985 Ma (U–Pb zircon). The ophiolite is structurally dismembered and thrust over the Proterozoic shelf sequence that covers the north margin of the Yangtze craton, and overrode a flysch to conglomerate-wildflysch unit shed from the ophiolite and a magmatic arc terrane and deposited on the older Yangtze carbonate platform. The youngest clasts in the conglomerate are circa 861–813 Ma (U–Pb zircon), giving a maximum age for ophiolite emplacement. Fine-grained layered amphibolites exhibit slightly depleted-flat type REE curves with no obvious Eu anomalies, and are N-MORB type tholeiites. Metagabbro has typical cumulate textures, flat REE distributions and obvious positive Eu anomalies. The REE characteristics of serpentinized dunites show a U-shape of slight loss of middle REE, representing cumulates metasomatized by LREE slightly enriched mantle. All these features indicate that the metamafic–ultramafic rocks from the Proterozoic Miaowan Formation form a structurally dismembered ophiolite resting above an ophiolitic wildflysch, sitting on top of the Proterozoic shelf sequence on the Yangtze craton. The ophiolite is contemporaneous with an arc sequence preserved to the north on the edge of the Yangtze craton, suggesting that the entire ophiolitic forearc–arc was accreted to the Yangtze craton between 1000 and 850 Ma. Xenocrystic zircons in granite clasts in the basal wildflysch unit have ages consistent with Australian affinity, and detrital zircons in the arc sequence also show derivation from Australia, suggesting that the arc formed on the Australian segment of Rodinia before collision with the Yangtze craton. The discovery of the Proterozoic Miaowan ophiolite supplies important evidence for the existence of a Neoproterozoic oceanic basin on the north margin of the Yangtze craton, and demonstrates that the Yangtze craton first collided with Rodinia on its northern margin, with subsequent accretion of the Cathaysian block on the southern margin of the craton.     

http://www.sciencedirect.com/science/article/pii/S1674987111001320

Ectomycorrhizal fungi,a group of widcspread symbiotic fungi with plant,obtain carbon source from trees and improve plant mineral nutrient uptake with their widespread hyphal network.Ectomycorrhizal fun...     

Sobol’ sensitivity analysis of parameters in the common land model for simulation of water and energy fluxes

The water and energy transfer of land surface is complex due to its large spatial and temporal variability. The modeling and simulation is an important means to study land water and energy transfer, but most selection and analysis of model parameters are empirical and qualitative. This paper has proposed a method of quantitatively identifying the most influential parameters of Common Land Model through Sobol?? sensitivity analysis. Considering sensible heat flux as the model output, the first order and total sensitivity indices of 25 model input parameters are estimated using an improved Sobol?? method. The simulated results are resampled using a bootstrapping method and the corresponding sensitivity indices are calculated. Confidence intervals for the bootstrapping sensitivity indices are estimated by using a percentile method. The results show that the parameters phi0 and porsl are the most important parameters, followed by ref(2,1), tran(2,1) and bsw. Five out of 25 parameters need to have an accurate evaluation, while the other parameters are fixed to a certain value. The sensitivity indices of parameters phi0 and porsl are decreasing after precipitation, while the sensitivity indices of parameters tran(2, 1) and ref(2, 1) are increasing after precipitation.     

Trace element and REE geochemistry of fine- and coarse-grained sands in the Ordos deserts and links with sediments in surrounding areas

In addition to mineral analyses, REE and trace element geochemical characteristics of fine- and coarse-grained sands in the Ordos deserts and other sediments in surrounding areas are investigated.Commonly the samples consist of quartz, feldspar and muscovite and less clinochlore, dolomite and ankerite. In few samples muscovite is absent.REE and trace compositions are spatially uniform for the same grain-size sands, suggesting that they could have the same sources or/and were well homogenized. However, fine- and coarse-grained sands in the Ordos deserts show different REE and trace element compositions. Fine-grained sands show higher contents of REE and trace elements than those of coarse-grained sands. They differ in Eu anomalies and (La/Yb)_N ratios although both fractions are characterized by the steep LREE and smooth HREE patterns. The fine- and coarse-grained sands are also distinct in some characteristic element ratios (e.g., Th/Co, La/Sc, Th/Sc and Y/Ni).REE and trace element patterns of the two different grain-size fractions are closely associated with geological properties of individual sources rather than the mineralogical differentiation induced by wind sorting. The coarse-grained sands mainly resulted from sandstone weathering in the Ordos deserts and movements of coarse particles by wind. REE and trace element patterns of fine-grained sands in the Ordos deserts differ from those of sandstones in the Ordos deserts, the alluvial sands in the surrounding mountains and the coarse fluvial sands in the Yellow River. They resemble the fine fluvial sands in the Yellow River. In addition, arid areas of Northwest China such as the Tarim Basin and the Alxa Plateau should not be ruled out as the source of the fine-grained sands in the Ordos deserts because these arid areas reserve plenty of fine-grained sediments and also located in the upwind directions of the Ordos deserts.     

Pseudofrenelopsis fossils from Cretaceous gypsum beds in Guixi,Jiangxi Province,China and their geological significance

Compressed fossil plants were found in the gypsum beds of the Zhoujiadian Formation in Guixi City, Jiangxi Province, China. The cuticular features of two species of Pseudofrenelopsis (Cheirolepidiaceae) were examined by scanning electron microscopy in this study: Pseudofrenelopsis papillosa Cao ex Zhou and Pseudofrenelopsis guixiensis Bainian Sun et Dai, sp. nov. A detailed analysis of the internode epidermis, and the adaxial and abaxial leaf cuticles of the two species, was performed, extending our knowledge of the morphological and anatomical characteristics of the extinct Pseudofrenelopsis. A new species, Pseudofrenelopsis guixiensis sp. nov., is proposed based upon comparison of its cuticular features. It differs from previously published species in that it has hairs on the abaxial surfaces of its leaves, sometimes shares subsidiary cells on the surfaces of internodes, lacks a hypodermis, and has no papillae on its epidermal cells. Because the distribution of fossil Pseudofrenelopsis is restricted to the Lower Cretaceous, the Early Cretaceous age of the Zhoujiadian Formation is affirmed. The fossils of Pseudofrenelopsis show obvious xeromorphic characteristics, such as apparent thickening of the cuticles, subsidiary cells with obvious papillae, and anticlinal walls with strong cutinization, and they are found associated with gypsum beds and close to red beds. All of these features indicate an arid climate.     

Experimental researches on reflective and transmitting performances of quarter circular breakwater under regular and irregular waves

A series of regular and irregular wave experiments are conducted to study the reflective and transmitting performances of quarter circular breakwater (QCB) in comparison with those of semi-circular breakwater (SCB). Based on regular wave tests, the reflection and transmission characteristics of QCB are analyzed and a few influencing factors are investigated. Then, the wave energy dissipation as wave passing over the breakwater is discussed based on the hydraulic coefficients of QCB and SCB. In irregular wave experiments, the reflection coefficients of QCB and their spectrums are studied. Finally, the comparisons between the experimental results and numerical simulations for QCB under regular and irregular wave conditions are presented.     

Effects of sand grain size and morphological traits on running speed of toad-headed lizard Phrynocephalus frontalis

We conducted a manipulative experiment to investigate the influential factors of locomotor ability in steppe toad-headed lizards. By using a video-base method, we measured running speed of the lizards when they run on sands of different grain sizes. We also considered body condition, tail length and sex as fixed factors to analyze their effects on running speed of the lizard. Results showed that running speed of the lizard significantly differed among different trials of sand grain size. Specifically, the peak and the nadir values of the running speed were found on sands of 0.5-1 mm and 0.075-0.25 mm grains, respectively. When lizards ran on sands of different grain size their running speed changed significantly. Body condition and tail length also had significant effects on running speed. The findings indicated that locomotor ability of lizards depended on both body condition and the external environment. We hypothesized that sand grain size is one of the factors that influence the habitat selection in steppe toad-headed lizards. Moreover, this lizard may be used as an indicator of the development of sand dunes.     

土地利用结构与社会经济结构——基于中国不同用地类型区域的实证分析

应用简单相关分析、典型相关分析以及聚类分析等方法,选取1999-2007年中国31个省市(除港澳台地区)的面板数据,对全国及不同用地类型区域的土地利用结构与社会经济结构的关系进行实证分析.研究表明,我国土地利用结构与社会经济结构的相互影响关系显著,产业结构的升级以及土地利用结构的优化相互作用,并对中国社会经济发展具有显著贡献:土地利用结构与社会经济结构的关系具有显著的区域差异性,基于不同用地类型区域的分析有助于二者量化关系规律的进一步显化:相应的政策含义是,土地宏观调控政策应与产业政策相协调,并兼具宏观政策和区域政策的双重特点.