Impact of water diversion on the morphological development of the Lower Yellow River

In this paper we carry out a theoretical analysis based on the general one-dimensional morphodynamic model for rivers in order to show how the morphological equilibrium of a fiver is influenced by water and sediment diversion/supply along the river. The results of the analysis show that large scale water diversions, like those along the Lower Yellow River, can cause the development of a convex riverbed profile in the long-term. Deposition will take place along the whole reach of the river, with an increasing deposition depth from downstream to upstream. The slope of the river bed increases from upstream to downstream. Furthermore, an analysis on the morphological time scale shows that this development in the Lower Yellow River will take a time period on the order of decades to centuries. The results of the analysis have been compared with observations in the Lower Yellow River. Since the second half of the 1980＇s large scale water diversions from the Yellow River have been taking place. The observations show that this has indeed led to significant sedimentation along the river.     

矿产资源储量核查中测量精度分析

在矿山资源储量核查中，应对其采矿工程测量资料进行检测。检测项目包括基本控制点、近井点和高程基点、井口坐标、井下导线点及高程基点、井下巷道及采区范围，并根据有关规范推算其测量精度及误差范围，进而对矿山原有资料进行评述。     

夏季闽东沿海水体中透明胞外聚合颗粒物的分布特征及影响因素

透明胞外聚合颗粒物(TEP)在海洋微食物网和海洋碳循环中发挥着重要作用。本文针对夏季闽东沿海TEP的分布特征及影响因素进行研究。结果表明,闽东沿海TEP含量(以黄原胶为标准物质计算,后同)范围为25.2～935.5 μg/L,平均值为(201.8±177.9) μg/L。整体而言,TEP的分布表现为近岸高、远岸低,表层TEP含量相对于底层要低。相关性分析显示,研究海域TEP含量与浊度和营养盐(硅酸盐、磷酸盐、硝酸盐、亚硝酸盐和铵盐)浓度呈正相关,与pH、溶解氧浓度和小型浮游生物量呈负相关。分级叶绿素a结果显示,相对于其他尺寸浮游植物,调查海域小型浮游生物可能对TEP含量的贡献最大。相比于开阔大洋中TEP主控因素为浮游植物而言,夏季闽东海域TEP主要由浮游植物在衰退阶段产生,其分布主要受颗粒物再悬浮作用影响。该结果不仅进一步阐明了近岸海域与开阔大洋TEP影响因素的区别,并且对我国近海海域不同区域TEP分布研究空白进行了补充。     

长江口水下三角洲演变规律及河势控制初探

长江河口区水下三角洲的稳定关系着河口区域滩涂湿地的保护、经济社会的发展,研究长江河口区水下三角洲的变化规律,制定相应的控制对策有着重要的意义。基于长江河口区水下三角洲近40年的4个测次的地形资料,采用平面形态与断面形态分析相结合的方法,探讨了长江河口区水下三角洲的变化规律和相应的控制对策。总体来看,受入海沙量减少的影响,长江河口区水下三角洲前缘10～20 m等深线之间的区域冲刷明显。崇明东滩沙体总体变化不大,横沙东滩、南汇边滩在圈围工程影响下,面积有所淤长。横沙浅滩、九段沙窜沟发育,切割洲滩,沙体稳定性受到威胁,建议对横沙浅滩、九段沙实施守护,以控制长江河口区河势稳定。     

南极普里兹湾表层沉积物中磷的形态分布特征

针对多次南极考察中雪龙号在普里兹湾海域获取的表层沉积物样品,分析了该海域沉积物中各形态磷的含量,并讨论了其分布特征和控制因素。结果表明,表层沉积物总磷含量介于416.1×10-6—676.3×10-6之间,平均为543.5×10-6,主要由碎屑磷(平均为209.9×10-6)和自生磷(平均为137.7×10-6)组成。自生磷、有机磷呈现从湾东部至西部逐渐降低的分布趋势,这种分布与有机碳、生物硅等生源要素的分布以及上层水体生产力的高低相吻合,指示了其海洋生源属性;碎屑磷在湾西部含量较高,其分布与沉积物中铝、砂质的分布模式一致,表明其主要来自堆积在西部浅滩区域冰山携带的陆源砂质碎屑。可交换态磷(平均为36.0×10-6)和铁结合磷(平均为47.1×10-6)在沉积物中含量较低,分别受沉积物粒度和铁含量的控制,仅在湾东部和中心个别站位含量较高。生物可利用磷在湾东部和中心区域含量较高,可能与上述区域较高的生源颗粒物沉降速率有关,同时这些颗粒物可能吸附了水体中的磷进入沉积物中,导致对应底层海水磷酸盐浓度相对降低。     

青藏高原若干地点的第四纪冰川年代学* ——深切怀念孙殿卿院士

青藏高原第四纪冰川时空演化问题广受关注。应用宇宙成因核素暴露年龄测定方法开展高原古冰川的年代学研究,对青藏高原聂拉木、唐古拉山、义敦海子山和折多山等4个地区的第四纪冰碛物进行了\{¹⁰ Be\},²⁶ Al和²¹ Ne暴露年龄测定,获得了青藏高原不同地点第四纪冰川发育的年代学数据,结果表明青藏高原出现了多期第四纪冰期,分别为YD事件、末次冰期晚阶段、末次冰期早阶段、倒数第2次冰期和倒数第3次冰期。     

淄博地区上新世巴漏河组的发现及意义

上新世巴漏河组在淄博地区的发现填补了该地区上新统的空白。阐述了巴漏河组的空间展布特征及其对新构造运动的指示意义 ;综合运用沉积岩相分析、孢粉分析、岩石化学分析等方法对巴漏河组剖面进行了系统研究 ,分析了其成因及形成时代 ,重建了淄博地区上新世晚期的沉积、生态及气候等古地理环境。认为巴漏河组是在上新世晚期由河流搬运堆积形成 ,在其沉积过程中 ,淄博地区的植被由针阔混交林演替为以松为主的针叶林 ,气候由暖湿的暖温带气候向冷湿气候变迁 ,并呈现出进一步干冷化的趋势     

Comparison of sedimentary organic carbon loading in the Yap Trench and other marine environments

Journal of Oceanology and Limnology - Knowledge about organic carbon loadings (ratio of sedimentary organic carbon (SOC) content to specific surface area (SSA)) and the fate of organic carbon (OC)...     

利用高支链类异戊二烯(HBIs)重建极地海冰的研究进展

海冰的准确重建对反演气候和环境变化具有重要意义。近期研究表明,有机指标高支链类异戊二烯(HBIs)具有重建极地海冰状况的潜质,海洋沉积物中具有海冰特异性的单烯HBI(IP_(25))和双烯HBI(IPSO_(25))指标已分别成为研究北极和南极海冰变化的有力工具。本文综述了IP_(25)、IPSO_(25)的提出和验证,分析了影响HBIs生成、迁移和埋藏的诸多因素,总结了为实现精细化区分海冰状况和定量化重建海冰密集度而提出的新指标的发展及应用,并就目前存在的问题和未来研究方向进行了探讨和展望。     

Concentrations and distribution of biogenic barium in surface sediments of Prydz Bay, Antarctica

Concentrations ofbiogenic barium were investigated in surface sediments of Prydz Bay, Antarctica, during the 21st and 27th CHINARE cruises. Factors controlling the observed distribution are explored. Biogenic barium concentrations obtained from a sequential extraction procedure are compared with total concentrations obtained from the normative calculation based on a total digestion, and differences in the results are examined. Concentrations of biogenic barium, calculated by the normative calculation, were much higher than the concentrations obtained through sequential extraction; this discrepancy is the result of the occurrence of barium associated with Mn/Fe oxides, which represents an important component of total barium in these sediments. Concentrations of biogenic barium obtained from the sequential extraction range from 104 to 445 ktg.g1, and the average concentration was 227 p.g.g-~. The highest concentrations of biogenic barium occur in the central area of the bay, where the seawater is more stable, while lower values occur in the bank and the ice shelf. Biogenic barium is significantly linearly correlated with biogenic barium and organic carbon, and similar in distribution of Chl a, which may indicate that primary productivity of phytoplankton in the surface water column is the main environmental factor regulating barium concentration and distribution.