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CMIP5 Projections of Two Types of El Nino and Their Related Tropical Precipitation in the Twenty-First Century
No full textFuture projections of the eastern-Pacific (EP) and central-Pacific (CP) types of El Nino in the twenty-first century, as well as their associated tropical circulation and precipitation variability, are investigated using historical runs and representative concentration pathway 8.5 (RCP8.5) simulations from 31 coupled models in phase 5 of the Coupled Model Intercomparison Project (CMIP5). As inferred from CMIP5 models that best capture both El Nino flavors, EP El Nino sea surface temperature (SST) variability will become weaker in the future climate, while no robust change of CP El Nino SST is found. Models also reach no consensus on the future change of relative frequency from CP to EP El Nino. However, there are robust changes in the tropical overturning circulation and precipitation associated with both types of El Nino. Under a warmer climate, magnitudes of precipitation anomalies during EP El Nino are projected to increase, presenting significant enhancement of the dry (wet) signal over the western (central-eastern) Pacific. This is consistent with an accelerated hydrological cycle in the deep tropics; hence, a "wet get wetter'' picture appears under global warming, accompanied by a weakened anomalous Walker circulation. For CP El Nino, drier-than-normal conditions will be intensified over the tropical central-eastern Pacific in the future climate, with stronger anomalous sinking related to the strengthened North Pacific local Hadley cell. These results suggest that, besides the enhanced basic-state hydrological cycle over the tropics, other elements, such as the anomalous overturning circulation, might also play a role in determining the ENSO precipitation response to a warmer background climate
Spatio-temporal Variability in Sea Surface Temperatures for the Yellow Sea based on MODIS Dataset
No full textThe spatio-temporal variabilities in sea surface temperature (SST) were analyzed using a time series of MODIS datasets for four separate regions in the Yellow Sea (YS) that were located along a north-south axis. The space variant temporal anomaly was further decomposed using an empirical orthogonal function (EOF) for estimating spatially distributed SST. The monthly SSTs showed similar temporal patterns in each region, which ranged from 2.4 degrees C to 28.4 degrees C in the study years 2011 to 2013, with seasonal cycles being stronger at the higher latitudes and weaker at the lower latitudes. Spatially, although there were no significant differences among the four regions (p<0.05) in any year, the geographical distribution of SST was characterized by an obvious gradient whereby SST decreased along the north-south axis. The monthly thermal difference among regions was largest in winter since the SST in the southeast was mainly affected by the Yellow Sea Warm Currents. The EOF1 mode accounted for 56% of the total spatial variance and exhibited a warming signal during the study period. The EOF2 mode accounted for 8% of the total variance and indicated the warm current features in the YS. The EOF3 mode accounted for 6% of the total variance and indicated the topographical features. The methodology used in this study demonstrated the spatio temporal variabilities in the YS
Lower Silurian stromatolites in shallow-marine environments of the South China Block (Guizhou Province, China) and their palaeoenvironmental significance
No full textIn northern Guizhou Province (Upper Yangtze Platform, South China Block) two types of reef communities developed in the Lower Silurian (upper Aeronian, Llandovery) Shihniulan Formation; they are calcimicrobial- and metazoan-dominated structures, and existed because of northward deepening of the shallow-marine ramp setting in which they grew. Stromatolitic communities are the focus of the present study and dominated the shallowest reef structures, while metazoan-dominated reefs, previously described in other papers, grew in the outer shelf portion of the ramp. Stromatolitic reefs occur in several sections (Daijiagou, Baishanxi, jianba and Lianghekou), palaeogeographically close to Qianzhong Land. Within the stromatolite units, laminar sheets of microbial mats and columns are pronounced, with individual stromatolite thicknesses generally less than 1 m. Some very small stromatolites are only centimeters in diameter and thickness. Stromatolitic units are cyanobacterial bindstones mostly associated with shales, siltstones and thin-bedded bioclastic limestones. Their growth was frequently punctuated by siliciclastic sediments, and their shallow-water nature is demonstrated by association with birds-eye structures, cross-stratified sediments, and Lingulella-bearing silts in intertidal or/and lagoonal environments. The stromatolites formed during a regression and erosion surfaces are common at the top of the Shihniulan Formation. The Tongzi Uplift, a short-duration expansion of Qianzhong Land, ended the deposition of the late Aeronian limestones. (C) 2016 Elsevier B.V. All rights reserved
Selective Fenton-like oxidation of methylene blue on modified Fe-zeolites prepared via molecular imprinting technique
No full textA facile strategy to increase the selectivity of heterogeneous Fenton oxidation is investigated. The increase was reached by increasing selective adsorption of heterogeneous Fenton catalyst to a target pollutant. The heterogeneous Fenton catalyst was prepared by a two-step process. First, zeolite particles were imprinted by the target pollutant, methylene blue (MB), in their aggregations, and second, iron ions were loaded on the zeolite aggregations to form the molecule imprinted Fe-zeolites (MI-FZ) Fenton catalyst. Its adsorption amount for MB reached as high as 44.6 mg g (-1) while the adsorption amount of un-imprinted Fe-zeolites (FZ) is only 15.6 mg g (-1). Fenton removal efficiency of MI-FZ for MB was 87.7%, being 33.9% higher than that of FZ. The selective Fenton oxidation of MI-FZ for MB was further confirmed by its removal performance for the mixed MB and bisphenol A (BPA) in solution. The removal efficiency of MB was 44.7% while that of BPA was only 14.9%. This fact shows that molecular imprinting is suitable to prepare the Fe-zeolites (FZ)-based Fenton catalyst with high selectivity for removal of target pollutants, at least MB
Spatial variations in the effective elastic thickness of the lithosphere in Southeast Asia
No full textAs a proxy for long-termlithospheric strength, detailed information on lateral effective elastic thickness (T-e) variations can aid in understanding the distribution pattern of surface deformation and its response to long-term forces. Here we present high-resolution maps of spatial variations of T-e for the complex SE Asian region by analyzing the coherence of topography and Bouguer gravity anomaly data. We find that after considering the gravity deficit of less dense sediment, the recovered T-e maps are more representative of the geology, particularly in elongated rift basins. The results show that the T-e variation pattern in SE Asia, in general, agrees well with its tectonic provinces and major tectonic boundaries. The oceanic basins, the Indosinian suture zones between the Indochina and Sibumasu blocks, and the Makassar Strait are characterized by low T-e, while moderate and high T-e values are recovered in the Khorat plateau, West Burma, the Singapore Ridge, the Con Song Swell, Borneo, the northern Australian margin and the Molucca Sea. The T-e pattern in the south Indonesian margin is complicated by the approach and collision of oceanic plateaus and seamounts with the fore-arc region. The heterogeneous strength features are consistent with the complex assemblage of different tectonic units, and significant deformation during Cenozoic tectonic events. In the Indochina Peninsula, the extruded displacement during the India-Eurasia collision might have been partitioned and absorbed by the combined mechanism of the extrusion and viscous tectonic models. As a result, the offshore displacements of the major strike-slip faults in the South China Sea are much smaller than originally assumed, thus having less effect on the development of the South China Sea than other mechanisms such as the slab pull of the proto-South China Sea. Since the displacement driven by the boundary tectonic forces has been greatly absorbed and decreased by subduction and deformation in the active margins and adjacent weak regions, the motion velocity of the interior regions is greatly lower than the boundary active margins, and they are largely free of seismicity and volcanism. Our results suggest that East Borneo might share a similar crustal basement, and represent a broad tectonic zone of the destroyed Meso-Tethys Ocean extending from West-Middle Java, through East Borneo to northern Borneo of the Sarawak and Sabah. The Indosinian zones between the Indochina and Sibumasu blocks might extend further southeastward across Billiton Island to offshore of southern Borneo, and the Singapore platform and SW Borneo might belong to the same block. The results also show that the internal load fraction F is high in the coastal area of South China, the northern margin of the South China Sea, and the coastal area of Indochina, which, in general, agrees with the distribution of a high-velocity lower crustal layer and Late Cenozoic basaltic rocks. (C) 2016 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved
Preface: Magmatic and Tectonic Process, Seabed Resource from the mid-ocean ridge to continental margin
No full text溶藻弧菌噬菌体VP670生物学特征及其內溶素cwl Q、穿孔素holA基因功能研究
No full text溶藻弧菌（Vibrio alginolyticus）是一种常见的海洋致病菌。噬菌体（Bacteriophage）是一种能够侵染细菌并在宿主细菌体内进行增殖的病毒，作为细菌的天然杀手，噬菌体在自然界中广泛分布，在细菌性感染尤其是多重耐药菌感染的治疗方面具有抗生素无法比拟的优势。利用噬菌体进行人类和水产动物弧菌病防治已经有一些报道，并且分离出一些噬菌体，但是很少见溶藻弧菌噬菌体的分离、全基因序列和噬菌体基因功能研究的报道。本文从湛江沿岸海水中分离出一株溶藻弧菌致病株E06333的噬菌体VP670，经鉴定属于短尾噬菌体科自复制短尾噬菌体亚科的种类。依托Illumina Miseq测序平台对噬菌体VP670进行测序并完成全基因组测序，序列分析表明：噬菌体VP670基因组DNA包含49个开放式阅读框，43121个核苷酸，GC含量为43.4%。整个噬菌体VP670基因组包含复制与调节模块，组装模块，裂解模块和结构模块这四个模块，。
噬菌体VP670包含一个穿孔素基因（holA）和一个内溶素基因(cwlQ)，基因功能预测其组成一个二元系统对宿主菌进行裂解。cwlQ 产物CwlQ无信号肽序列也无跨膜结构域序列。
将holA与cwlQ二基因融合片段及单独的cwlQ插入到pBAD18kan表达载体上，构成的重组质粒pBAD18kan-holA-cwlQ及pBAD18kan-cwlQ。pBAD18kan-holA-cwlQ在大肠杆菌DH5α中诱导表达时，产生显著的溶菌作用，然而pBAD18kan-cwlQ诱导表达时，并不能产生溶菌作用。结果表明，CwlQ确实具有强烈的溶菌作用，但当在细菌体内表达时，必须经由HolA形成的孔洞到达肽聚糖层的作用位点，才能起到溶菌作用。holA 及cwlQ功能研究，为进一步利用噬菌体VP670生物防治溶藻弧菌病及cwlQ工程化应用打下了基础。
由于缺乏噬菌体基因组提取的方法，本研究过程中，也探索发明了一种通用的噬菌体基因组提取的方法并开发成试剂盒，结果表明，通过此试剂盒提取的噬菌体基因组DNA不仅纯度高，可以满足下游实验需求且无宿主菌DNA污染
电沉积技术促进造礁石珊瑚钙化的研究
No full text电沉积技术是一项可用于珊瑚礁修复的有效技术之一，但是该项技术应用的机理和具体的使用参数研究较少，研究文献报道对其效果如何尚有争议。研究者大都选用单一的电压或电流条件来描述其电作用环境，没有测量电流密度等其它参数，同时采用的电流电压较高。而且研究者者往往也没有对电极材料（尤其是阴极材料）应用效果进行全面的评估。目前，电沉积对造礁石珊瑚骨骼中碳酸钙晶体结构的影响这一微观层面对电沉积技术机理的解释，尚没有相关报道。
针对上述研究现状，本研究选择电流密度参数做为衡量电作用条件的单位，设置一定梯度的电流密度条件，用电沉积技术在海水中获得碳酸钙晶体，研究其成分组成与结构特点；并应用电沉积技术于造礁石珊瑚成体培殖实验，在阴极材料的选用上，设置了导电性相差较大的两种材料作为培植造礁石珊瑚基底，观测其对造礁石珊瑚钙化生长速率和光合作用的影响；采用电沉积技术研究中普遍采用的不锈钢材料，设置不同电流密度梯度对造礁石珊瑚进行较长时间的培养，观察造礁石珊瑚生长钙化速率、光合作用以及骨骼晶体结构。经过研究，得出以下结论：
1）在低电流密度条件下（1200mA/㎡或以下），随着电流密度的增大，电沉积物形成就越多，所形成的电沉积物的晶体结构和成分组成和造礁石珊瑚骨骼相似，皆含有文石结构，在600mA/㎡条件下，电沉积物的碳酸钙含量最高。
2）选择不同阴极材料，电沉积促进造礁石珊瑚生长效果有所区别，利用导电性较好的材料（如石墨）效果较好。
3）在低电流密度条件下培养造礁石珊瑚的前期阶段（30天），电沉积可促进造礁石珊瑚的钙化和光合作用，效果显著，而后期仍有效果，但是效果不明显，电流作用可以影响造礁石珊瑚骨骼晶体的结构，使其结构较为疏松
基于GIS和RS的海南新村港和黎安港非点源污染估算
No full text非点源污染来源广泛且受到复杂天气的影响，其污染量难以实际测量。国内外学者开发了多种模型来进行非点源污染的估算，随着遥感和GIS技术的发展，越来越多的研究都借助于遥感和GIS的手段来进行。非点源污染发生范围广，一般随着降雨径流进入水体，从而对水体产生影响，所以不同活动产生的非点源污染也主要通过降雨汇流进入海湾。发生范围通常利用流域的范围来确定，但是在缺乏水文资料的地区，其发生范围较难确定。基于GIS的水文分析为发生范围的确定提供了方法，通过使用DEM数据进行汇水区的划分，可以确定模拟流域汇水区范围，进而确定非点源污染的发生范围，本文正是借助这一方法来确定非点源污染的发生范围。
陆源非点源污染的产生量与土地利用类型密切相关，通过遥感影像能够较为直观地获取土地利用类型，由于海岸带特殊的地理环境，具有水陆混合的地物类别只通过光谱信息难以精确分类。为了提高海岸带地物分类的精度，叠加纹理信息实现海岸带的地物分类，对分类精度进行评价。结果表明，分类精度普遍或的提高，提高范围在0.16%~8.64之间。本文还通过探讨了不同纹理参数设置对于分类精度的影响，获得了分类精度最优的组合。
本文对灰度共生矩阵和分形纹理特征进行了对比研究研究，结果表明，基于双毯法的分形纹理特征分类精度优于基于灰度共生矩阵的纹理特征分类精度。研究还利用Sentinel 2A 10m数据和Landsat 8数据探讨了不同分辨率对于海岸带地物纹理特征提取的影响，结果表明，高空间分辨率对于纹理信息提取的影响效果明显，在使用相同数量波段进行分类时，Sentinel 2A数据分类精度高于Landsat 8数据；Landsat 8具有波段多的优势，通过与全色波段数据融合获得的15m影像更适宜应用到海岸带地物分类中。
新村港和黎安港位于海南省陵水黎族自治县，是海南省重要的渔港，两个港湾毗邻，自然和社会环境相似。该地区海水养殖业发达，是当地重要的经济来源，港湾水环境的健康直接影响到海水养殖这一重要支柱产业的发展。近年来，人类活动对港湾内的水环境的影响越来越大，海水养殖排放的大量有机污染物、渔民生活产生的生活废水、渔船运转带来的污染等污染带来的影响越来越严重，非点源污染的研究显得十分有必要。
通过汇水分析，划分获得影响新村港和黎安港陆源污染的来源范围分别是107km2和19.31km2，将其应用到非点源污染的陆源污染的估算中。通过对研究区域非点源污染的估算，获得新村港和黎安港的非点源污染的年负荷量，结果表明，新村港COD、TN、TP的年负荷量为565.55吨、130.79吨、11.55吨；黎安港的COD、TN、TP的年负荷量为113.48吨、28.33吨、2.80吨。污染物来源主要是海水养殖、生活污染和降雨径流污染
High Efficiency Hydrodynamic DNA Fragmentation in a Bubbling System
No full textDNA fragmentation down to a precise fragment size is important for biomedical applications, disease determination, gene therapy and shotgun sequencing. In this work, a cheap, easy to operate and high efficiency DNA fragmentation method is demonstrated based on hydrodynamic shearing in a bubbling system. We expect that hydrodynamic forces generated during the bubbling process shear the DNA molecules, extending and breaking them at the points where shearing forces are larger than the strength of the phosphate backbone. Factors of applied pressure, bubbling time and temperature have been investigated. Genomic DNA could be fragmented down to controllable 1-10 Kbp fragment lengths with a yield of 75.30-91.60%. We demonstrate that the ends of the genomic DNAs generated from hydrodynamic shearing can be ligated by T4 ligase and the fragmented DNAs can be used as templates for polymerase chain reaction. Therefore, in the bubbling system, DNAs could be hydrodynamically sheared to achieve smaller pieces in dsDNAs available for further processes. It could potentially serve as a DNA sample pretreatment technique in the future