Analysis of expressed sequence tags from the Ulva prolifera (Chlorophyta)

In 2008,a green tide broke out before the sailing competition of the 29th Olympic Games in Qingdao.The causative species was determined to be Enteromorpha prolifera (Ulva prolifera O.F.Müller),a familiar green macroalga along the coastline of China.Rapid accumulation of a large biomass of floating U.prolifera prompted research on different aspects of this species.In this study,we constructed a nonnormalized cDNA library from the thalli of U.prolifera and acquired 10 072 high-quality expressed sequence tags ...     

Overview on seagrasses and related research in China

Seagrass research in China is still in its infancy. Even though there has been progress recently, there is still a great deal of research needed to gain a better understanding of seagrass. In this article we review and discuss the advances in seagrass research in China from two aspects: (1) seagrass species and their distribution; (2) seagrass research in China, including studies on their taxonomy, ecology, photosynthesis, applications in aquaculture, salt-tolerance mechanisms and other research topics. A total of 18 seagrass species belonging to 8 genera are distributed in nine provinces and regions in China (including Hong Kong and Taiwan), as well as the Xisha and Nansha Archipelagos. They can be divided into two groups: a North China Group and a South China Group. Based on the seagrass distribution, the Chinese mainland coast can be divided into three sections: North China Seagrass Coast, Middle China Seagrass Coast, and South China Seagrass Coast. Ecological studies include research on seagrass communities, nutrient cycling in seagrass ecosystems, genetic diversity, pollution ecology and research in the key regions of Shandong, Guangdong, Guangxi, and Hainan. Seagrass species and their locations, community structure, ecological evaluation, epiphytes, ecological functions and threats in the key regions are also summarized. Other studies have focused on remote sensing of seagrass, threatened seagrass species of China, and pollen morphology of Halophila ovalis.     

Decomposition of algal lipids in clay-enriched marine sediment under oxic and anoxic conditions

A series of laboratory incubation experiments were conducted to examine the decomposition of algal organic matter in clay-enriched marine sediment under oxic and anoxic conditions. During the 245-day incubation period, changes in the concentrations of TOC, major algal fatty acid components (14:0, 16:0, 16:1, 18:1 and 20:5), and n-alkanes (C₁₆–C₂₃) were quantified in the samples. Our results indicate that the organic matters were degraded more rapidly in oxic than anoxic conditions. Adsorption of fatty acids onto clay minerals was a rapid and reversible process. Using a simple G model, we calculated the decomposition rate constants for TOC, n-alkanes and fatty acids which ranged from 0.017–0.024 d⁻¹, 0.049–0.103 d⁻¹ and 0.011 to 0.069 d⁻¹, respectively. Algal organic matter degraded in two stages characterized by a fast and a slow degradation processes. The addition of clay minerals montmorillonite and kaolinite to the sediments showed significant influence affecting the decomposition processes of algal TOC and fatty acids by adsorption and incorporation of the compounds with clay particles. Adsorption/association of fatty acids by clay minerals was rapid but appeared to be a slow reversible process. In addition to the sediment redox and clay influence, the structure of the compounds also played important roles in affecting their degradation dynamic in sediments.     

Response of regeneration diversity of <Emphasis Type="Italic">Carex Lasiocarpa</Emphasis> community to different water levels in Sanjiang Plain,China

The species diversity at the regeneration stage, inflenced by different water levels, is important for community composition in the later growing season. Regeneration diversity of Carex lasiocarpa community under different water levels was studied at two stages, recruitment and adult, in the Sanjiang Plain, Heilongjiang Province, China. The results showed that, at the two growing stages, important value of C. lasiocarpa population and species richness of the community decreased with the increasing water level, while the Simpson and Shannon-Wiener diversity indexes and Pielou evenness index increased. Under different water levels, community diversities were higher at the recruitment stage, while population important values of C. lasiocarpa were higher at the adult stage. Indexes in vegetation evaluation must be chosen prudentially for successful restoration and effective management of wetlands, and especially for wetland restoration, the optimal time should be selected according to the restoration objectives and costs.     

Land Use Allocation Based on Interval Multi-objective Linear Programming Model： A Case Study of Pi County in Sichuan Province

Adjusting and optimizing land use structure is one of the essential approaches to solve the conflict between land supply and demand. In this study,an uncertain interval multi-objective linear programming model was established and applied to analyzing the suitability of land use structure in Pi County of Sichuan Province. An adjustment scheme for optimizing land use structure was proposed on the basis of development planning drawn up by the local government. The results are summarized as follows: 1) the opti...     

Distribution and abundance of euphausiid larvae and salps during austral summers in Prydz Bay, Antarctica

The distribution and abundance of euphausiid larvae and salps was studied from samples collected in 2002 and 2006 from Prydz Bay, Antarctica.Larvae of Thysanoessa macrura and Euphausia superba were mainly distributed in the north of the continental shelf. T. macrura was more abundant and had a relatively wider distribution. In 2006, with ice having retreated and higher seawater temperatures and chlorophyll a levels, E. superba and T. macrura occurred in higher abundances and at more mature developmental stages. Euphausia crystallorophias was mainly distributed in the neritic region. In 2002, with severe ice conditions in the neritic region, abundance of E. crystallorophias was consisted of metanauplius (MN) and calyptopis I (CI). Salps, mostly Salpa thompsoni, had a low abundance in Prydz Bay. In 2002, S. thompsoni was only m)-3. In 2006, S. thompsoni was found at three stations located near the contimental factors, such as the timing of ice melt, polynya formation and food concentration appear to have a marked effect on the distribution and abundance of euphausiid larvae and salps.     

鄯勒油田西山窑组层序地层格架及其油气地质意义

运用层序地层学的基本原理和技术方法,建立鄯勒油田西山窑组层序地层格架,划分沉积相,并在此基础上分析层序地层格架内砂体的展布特征和油气的聚集规律,预测研究区岩性油气藏的类型及分布。研究结果表明：西山窑组整体经历了一个先进积、后退积的过程;西山窑组为一个三级层序,其中包含2个四级层序,该组由低位域（LST）的三角洲前缘沉积、湖侵域（TST）的三角洲平原沉积和高位域（HST）的湖相沉积组成。研究区基准面上升期可以寻找砂体上倾尖灭型岩性圈闭,基准面下降期可以寻找砂岩透镜体岩性圈闭。西一、二段沉积的三角洲河道砂体受后期构造运动的影响,可以形成砂体上倾尖灭型岩性油气藏;而西三、四段的湖相浊积砂体,可以形成砂岩透镜体岩性油气藏。     

盐岩蠕变相似模型及相似材料研究

相似材料模型试验是研究岩土工程的重要手段之一。基于相似理论,应用量纲分析法,推导考虑盐岩蠕变特性的相似模型,得到相关参数的相似判据,并以不同粒径的工业盐、精铁粉为骨料,环氧树脂、乙二胺为黏合剂构成相似材料,经过大量的材料配比力学试验,得到了一种基本满足金坛盐岩蠕变相似模型要求的材料配比,为开展盐岩地下油气储库建造及运营期的变形、破坏相似材料模型试验打下了坚实的基础     

峡口高地应力软岩隧道施工监测及支护对策研究

针对高应力软岩公路隧道的特点,对湖北宜巴高速公路峡口隧道开展了地应力测试、隧洞收敛下沉、接触应力、结构受力等项目的监测工作。地应力测试结果表明,虽然隧洞埋深不大,但由于构造应力的存在,仍属于高地应力区。施工监测结果表明,高应力软岩隧道变形与结构受力具有明显的时空效应,与开挖方式、工作面距离以及支护时机密切相关。由于隧洞围岩软弱破碎,加之处于高应力作用下,在工作面通过后,岩体产生持续性的流变变形,导致隧洞产生挤压大变形和结构受力的持续增加,达到支护结构强度极限,最终导致围岩失稳和支护体系的失效。基于上述研究成果,提出了相应的高应力软岩大变形支护设计对策。研究成果为高应力软岩隧道变形与结构受力的时空效应性提供了监测数据支持,为峡口隧道的施工和支护设计提供了依据,对我国西部其他高应力软岩公路隧道的建设具有借鉴意义     

有机质生烃动力学参数研究进展:回顾和展望

生烃动力学,作为一种动态的研究方法,在研究有机质生烃机制和解决油气勘探实际问题中具有独特的优势,因此得到了极大的发展.由于在不同地质背景下形成的不同或相同类型的有机质,其生烃动力学参数存在明显差异,这动摇了以典型干酪根类型为基础发展起来的传统生烃模式,给实际应用带给困难.所以,必须针对具体盆地特定烃源岩进行生烃动力学实验,求取特定烃源岩的生烃动力学参数,这样才能准确地模拟出盆地的生烃过程.为了逼近地质实际,更加精确地描述有机质生烃动力学参数,应加强对有机质分子结构的研究,探讨温、压共同作用下有机质生烃动力学模型.此外,中国南方海相碳酸盐岩生烃动力学的研究将是今后生烃动力学的重要发展趋势之一.