有关地理学研究中几个学术问题的研讨——学习黄秉维院士严谨治学的精神

黄秉维院士是我国地学、资源、环境领域的伟大思想家与设计大师。作为新中国地理学奠基人, 他为我国地理科学的发展做出了巨大贡献。值黄秉维院士诞辰百年之际, 作者回顾了黄秉维院士提出的四个学术问题:“生态环境”、“水热平衡在地理学研究中的作用”、“确切地估计森林的作用”和“钝端科学”, 并结合作者的相关研究工作阐述了对这四个问题的认识与体会, 以印证他的学术思想对后学者研究工作的重要引领与指导作用。     

西太平洋暖池核心区晚第四纪颗石藻属种变化及对环境演化的响应

对西太平洋暖池核心区KX97321-2站位380ka以来的颗石藻化石进行了属种鉴定及百分含量分析。结果显示,380ka以来Florisphaera profunda百分含量升高,对应营养跃层加深,初级生产力降低,Gephyrocapsa spp.的百分含量降低;在中布容期,Gephyrocapsa caribbeanica是优势种,是对中布容期特殊的环境条件适应演化的结果;对380ka以来F.profunda换算的初级生产力进行频谱分析,发现有100ka周期和30ka周期,而分段分析发现,0～80ka和320～380ka 2万年周期明显,中间80～320ka 4万年周期明显。     

安徽省地震应急三级响应指挥技术系统研究

地震应急响应系统是地震应急管理最重要的组成部分,有本地化特色的应急响应指挥技术系统对提高地震应急响应效率起到关键性的作用。介绍了基于ArcEngine、MapInfo、Visual Studio 2005、Java和网络模型技术研发的安徽省地震应急三级响应指挥技术系统的需求分析、数据库更新、建筑物震害模型研究、系统研发与集成、各子系统功能。实现了省内MS3.0以上地震分三级响应的功能,实用性较强,在地震应急演练和应对安徽省有感地震、轻微破坏性地震以及破坏性地震时发挥了重要作用。     

缅甸安达曼海弧后坳陷天然气成藏要素及成藏模式

缅甸安达曼海已成为中国石油企业的重要海外探区之一。受印度板块向欧亚板块和西缅甸微地块多期斜向俯冲的影响,该区先后经历了被动陆缘、过渡型陆缘及主动陆缘的演化阶段,盆地属性与油气成藏特征极为复杂。通过系统梳理安达曼海弧后坳陷的烃源岩、储盖层、圈闭、输导体系与油气生-运-聚匹配史等成藏要素,总结出该区油气成藏主控因素。结果表明:本区发育渐新统—下中新统、中中新统与上新统3套泥质烃源岩,前二者为成熟烃源岩,后者为生物气源岩;岛弧带上碳酸盐岩礁体与斜坡带上砂体的储集条件良好;斜坡带继承性古隆起之上的断背斜圈闭容积大;高角度张性断裂与连通性砂体分别构成以垂向、侧向为主的输导体系。结合油气成因、运移方式与圈闭类型的主要特征,建立了2种成藏模式:①中央凹陷带浅层生物气或混源气垂向运移断块圈闭成藏模式;②东部斜坡带、西部斜坡和岛弧带热解气侧向运移断背斜-岩性圈闭成藏模式。西部斜坡及岛弧带上的碳酸盐岩礁体和东部斜坡带继承性古隆起之上的大型断背斜是有利勘探目标。     

Seismic records of late Pleistocene aridity in Lake Tanganyika,tropical East Africa

New intermediate-resolution, normal-incidence seismic reflection profiles from Lake Tanganyika’s central basin capture dramatic evidence of base-level change during two intervals of the late Pleistocene. Four seismically-defined stratigraphic sequences (A–D) tied to radiocarbon-dated sediment cores provide a chronology for fluctuating environmental conditions along the Kalya Platform. Stacked, oblique clinoforms in Sequence C are interpreted as prograding siliciclastic deltas deposited during a major regression that shifted the paleo-lake shore ∼21 km towards the west prior to ∼106 ka. The topset-to-foreset transitions in these deltas suggest lake level was reduced by ∼435 m during the period of deposition. Mounded reflections in the overlying sequence are interpreted as the backstepping remnants of the delta system, deposited during the termination of the lowstand and the onset of transgressive conditions in the basin. The youngest depositional sequence reflects the onset of profundal sedimentation during the lake level highstand. High amplitude reflections and deeply incised channels suggest a short-lived desiccation event that reduced lake level by ∼260 m, interpreted as a product of Last Glacial Maximum (32–14 ka) aridity. Paleobathymetric maps constructed for the two interpreted regressions reveal that despite the positive lake-floor topography created by the Kavala Island Ridge Accommodation Zone, Lake Tanganyika remained a large, mostly connected water body throughout the late Pleistocene. The results of this analysis further imply that Lake Tanganyika is the most drought resistant water body in the East African tropics, and may have acted as a refuge for local and migrating fauna during periods of prolonged aridity.     

激光高度计卫星ICESAT在地学研究中的应用

介绍了世界首颗激光高度计卫星ICESat及其惟一有效的载荷——地学激光测高系统(GLAS)以及它的科学研究目的和工作原理,论述了ICESat在地学研究中的应用。     

Seasonal temperature responses to land-use change in the western United States

In the western United States, more than 79 000 km² has been converted to irrigated agriculture and urban areas. These changes have the potential to alter surface temperature by modifying the energy budget at the land–atmosphere interface. This study reports the seasonally varying temperature responses of four regional climate models (RCMs) – RSM, RegCM3, MM5-CLM3, and DRCM – to conversion of potential natural vegetation to modern land-cover and land-use over a 1-year period. Three of the RCMs supplemented soil moisture, producing large decreases in the August mean (− 1.4 to − 3.1 °C) and maximum (− 2.9 to − 6.1 °C) 2-m air temperatures where natural vegetation was converted to irrigated agriculture. Conversion to irrigated agriculture also resulted in large increases in relative humidity (9% to 36% absolute change). Modeled changes in the August minimum 2-m air temperature were not as pronounced or consistent across the models. Converting natural vegetation to urban land-cover produced less pronounced temperature effects in all models, with the magnitude of the effect dependent upon the preexisting vegetation type and urban parameterizations. Overall, the RCM results indicate that the temperature impacts of land-use change are most pronounced during the summer months, when surface heating is strongest and differences in surface soil moisture between irrigated land and natural vegetation are largest.     

海洋浮游植物病毒的研究进展

海洋浮游植物病毒在海洋生态系统中,特别是在赤潮的消亡过程中起了很重要的作用。介绍了海洋浮游植物病毒的种类、多样性和丰度分布及其在海洋生态系统中的主要作用和研究现状。重点介绍和比较了海洋浮游植物病毒多样性、丰度的DNA聚合酶链扩增法(PCR)、透射电镜法、荧光显微镜法和流式细胞仪法等研究方法及其发展状况,以期为今后的研究奠定基础。     

皱纹盘鲍(Haliotis discus hannai)肠道潜在益生菌的筛选及对幼鲍生长的影响

采用体外实验筛选益生菌结合16SrDNA序列分析法,从124株不具有溶血作用的皱纹盘鲍(Haliotis discus hannai)肠道细菌中筛选得到5株潜在益生菌并进行了分子鉴定,进一步对5株潜在益生菌进行了安全性实验及体内饲喂实验。结果表明,2株具有拮抗哈维弧菌和灿烂弧菌能力的潜在益生菌分别被鉴定为Shewanella sp.(WA64)和Shewanella sp.(WA65),一株产海藻酸酶和淀粉酶的潜在益生菌被鉴定为Vibrio sp.(WA51),产蛋白酶潜在益生菌被鉴定为Bacillus sp.(FA12),产琼脂酶潜在益生菌被鉴定为Tamlana sp.(FA86);安全性实验表明5株潜在益生菌在107cfu/ml下对皱纹盘鲍没有明显的毒害作用;通过体内饲喂实验发现,潜在益生菌WA64、WA65的复合作用能够显著提高幼鲍增重率和存活率(P<0.05),并在生产条件下能够明显降低幼鲍的死亡量。经抗生素敏感性实验,WA64菌株对15种抗生素均敏感或中度敏感,WA65菌株仅对庆大霉素和链霉素2种抗生素产生耐药。