The diversity and abundance of polychaetes (Annelida) are altered in sediments impacted by alumina refinery discharge in the Northern Territory,Australia

We collected polychaete diversity and abundance data at a range of impacted and reference sites near an alumina refinery in Melville Bay, northern Australia. The aims were to measure the impact of sediment modified by the alumina refinery discharge on polychaete communities and secondly to gather baseline data from which to measure future changes. Polychaete communities in both soft-bottom habitats and subtidal areas adjacent to mangrove forests were studied. We also developed and deployed an artificial substratum device to sample polychaetes associated with hard-substrate habitats. For each habitat, polychaete community composition was different between impacted and reference sites and at multiple time points. The impact of future changes either from bioremediation or management practices can be measured against these baseline data. Indicator species analysis was used to identify polychaete species that were significantly different at the locations tested, and we discuss their potential as indicator species.     

利用测井信息评价盐湖相烃源岩

盐湖相烃源岩富含膏、盐质成分,使其测井响应特征发生极大改变,给测井评价烃源岩带来困难。基于实测数据,分析了盐湖相烃源岩中普遍发育的纯泥岩、含膏(盐)泥岩和膏(盐)质泥岩有机碳含量的测井响应模式,发现纯泥岩和含膏(盐)泥岩TOC与AC和LogRt呈正比,与DEN呈反比,膏(盐)质泥岩TOC与DEN呈正比,与LogRt呈反比,并基于此建立了盐湖相烃源岩测井评价方法,即首先利用ΔGR区分岩性,再针对不同岩性建立TOC评价模型,最后根据实测S₁+S₂和TOC建立相关关系,就可以求取烃源岩的TOC和S₁+S₂。利用该方法对东营凹陷沙四下亚段烃源岩性质和展布进行分析,发现预测TOC与实测TOC吻合程度高,具有一定推广价值。     

低丰度碳酸盐岩有效烃源岩存在的 证据及其TOC下限

中国碳酸盐岩分布面积广、热演化程度高、有机质丰度普遍较低,研究低丰度碳酸盐岩能否成为有效烃源岩对评价碳酸盐岩油气潜力和勘探前景具有重要意义。多方面研究表明,随着深度增大或热演化程度的提高,碳酸盐岩烃源岩TOC降低、生烃潜力和残留烃量均表现出先增大后减小的趋势,生烃热模拟实验结果等都表明低丰度碳酸盐岩烃源岩可以发生生排烃作用,国外勘探实践亦发现低丰度碳酸盐岩作为烃源岩的油气田,这都表明低丰度碳酸盐岩可以成为有效烃源岩。确定碳酸盐岩烃源岩TOC下限需要考虑多个因素,研究认为碳酸盐岩烃源岩的TOC下限应该比泥页岩的05%低一些。根据排烃门限,利用生烃潜力法和物质平衡数值模拟计算法确定了不同成熟阶段有效烃源岩TOC下限,结合前人研究成果和勘探实践,综合确定低成熟阶段、成熟阶段和高过成熟阶段碳酸盐岩有效烃源岩的TOC下限分别为TOC≥14%、TOC=01%~14%和TOC＜01%。     

北京平原包气带典型沉积物对NH+4 N吸附特性研究

采用批实验方法,研究了北京平原典型沉积物对NH+4 N的吸附规律。结果表明颗粒越细的沉积物,达到吸附反应平衡所需的时间越长,对NH+4 N的吸附量也越大;NH+4 N初始浓度在0~50 mg/L范围内,Henry、Langmuir、Freundlich吸附等温模式均能较好地描述北京平原典型沉积物对NH+4 N的吸附特性。沉积物对NH+4 N的吸附量随初始浓度的增加而增加;沉积物的颗粒越细,Henry吸附系数K越大,单位质量沉积物的饱和吸附量也越大;沉积物中TOC含量对沉积物的NH+4 N吸附行为有一定的控制作用,永定河、潮白河沉积物TOC值与Henry吸附系数K的相关系数R2分别为050,076;沉积物对NH+4 N的饱和吸附量随着土水比的增加而减少,通过乘幂的方式拟合不同土水比下的饱和吸附量,得出了北京平原包气带沉积物对NH+4 N的饱和吸附量;相同岩性条件下,特别是细颗粒沉积物中,潮白河沉积物对NH+4 N的吸附能力较永定河沉积物强,而同一流域内,中、下游沉积物的吸附能力较上游强。     

Anthropogenic impacts recorded in the sediments of Lunawa, a small tropical estuary, Sri Lanka

The Lunawa Estuary has been selected as a model for studying the long-term diagnoss of tropical estuarine pollution and its impact on ecosystems. Surface and short-core sediments from the Lunawa Estuary were collected, and analyzed for total organic carbon (TOC), nitrogen, sulfur and hydrocarbon contents, hydrogen index and other related sediment properties. Water quality and surface sediment data indicate that the Lunawa Estuary is presently an anoxic water body. The upper part of the sediment cores, characterized by very high TOC values of more than 10%, and absence of bioturbation along with strong laminations indicate anoxic water since 1970 AD, determined by ¹⁴ C dating. However, before 1970 AD, lower TOC content and presence of bioturbation and homogenous sediments with animal traces suggest the presence of oxic bottom water and thus a much better physicochemical condition. The lower part of the cores may also suggest the influence of gradual global warming. Regular laminations in the upper portions of the cores probably resulted from monsoon pulses with material preserved under anoxic condition.     

Late Cenozoic Chemical Weathering and Environmental Changes Recorded in the Co Ngoin Sediments,Central Qinghai-Tibet Plateau

A series of faulted inland basins were developed in the central Qinghai-Tibet Plateau, among which the Co Ngoin Basin containing thick lacustrine sediments is located in the peripheral area of the Indian monsoon. In this paper, we present the weathering history and paleoclimatic changes in the last 2.8 Ma based on studies of high-resolution temporal distributions of Sr, Rb and Zr concentrations, Rb/Sr and Zr/Rb ratios and δ ^13C and TOC for the Co Ngoin sediments, in combination with the sediment properties, grain size distribution and clay mineralogy. The sedimentary records indicate three environmental stages in the last 2.8Ma. At the core depth of 197-170m (about 2.8-2.5Ma), low-intensity chemical weathering in the Co Ngoin catchment was experienced under warm-dry to cool-wet climate conditions with relatively low Sr concentration and high Rb/Sr and Zr/Rb ratios. The sudden occurrence of both subalpine coniferous forest and coarses and and gravel sediments in the Co Ngoin core reflects a strong tectonic uplift. The high Sr concentrations and low Rb/Sr and Zr/Rb ratios reflect a relatively strong chemical weathering between 2.5Ma and 0.8Ma (at the core depth of 170-38.5m) under a temperate/cool and wet climate, characterized by mud and silt with fine sand, probably indicating a stable process of denudation and planation of the plateau. Above the depth of 38.5m (about 0.8-0Ma), the coarsening of sediments indicates a strong tectonic uplift and a relatively low intensity of chemical weathering as supported by the record of sediments having relatively low Sr concentrations and high Rb/Sr and Zr/Rb ratios. Since then, the plateau has taken the shape of the modern topographic pattern above 4000m a.s.l.     

Preliminary Estimation of Paleoproductivity via TOC and Habitat Types： Which Method Is More Reliable？ -A Case Study on the Ordovician-Silurian Transitional Black Shales of the Upper Yangtze Platform, South China

New total organic carbon (TOC) data from the two Ordovician-Silurian transitional graptolite-bearing black shale intervals, the Wnfeng (五峰) Formation and the Longmaxi (龙马溪) Formation in Central Guizhou (贵州) and West Hubei (湖北), respectively, as well as previously reported TOC data from the same intervals in other places on the Yangtze platform of South China, have been used to produce an initial estimate of the primary paleoproductivity via a conventional inverse method (i.e., Rpp-inverse). The values of the Rpp-inverse are estimated to be 32 (43-21) gC/(m2·a) (Wufeng Formation) and 21 (27-16) gC/(m2·a) (Longmaxi Formation). Also, simultaneously, the habitat types (i.e., HT; cf., BA: benthic assemblage) and their temporal and spatial changes have been documented from the same succession, and an initial estimate of the primary paleoproductivity has been produced using a forward method (i.e., Rpp.forward). Being bounded mainly by the peritidai to inner-shelf environment shelly-facies or mixed-facies successions with BAI to BA3 faunas both at the top and the base, which indicates the habitat types from HT Ⅱ1 to HT Ⅲ2, the biohabitat type of the two graptolite-bearing black shale intervals can be limited to HT Ⅲ to HT Ⅳ, corresponding to the inner shelf to the outer shelf, with depths from roughly 60 m to 200-300 m. Based on the current data from the South China Sea and the southern part of the East China Sea, values of Rpp-forward should be about 100 to 400 gC/(m2·a). The difference in the results via the two methods suggests that paleoproductivity estimates from the geological strata need to be made cautiously, with particular attention paid to the paleogeographic setting, oxic-anoxic conditions, as also the preservation factor of organic carbon.     

过硫酸钾氧化法测定水中总有机碳

根据《海洋监测规范》规定的总有机碳分析方法 ,利用HW 5 61 0非色散红外CO2 气体分析仪 ,设计制造成功总有机碳分析装置 ,对《海洋监测规范》的方法进行了根本的改进 ,方法成熟可靠。用该仪器和方法测定TOC ,检出限低于 0 .0 1mg/L ,重现性优于 1 % ,达到了与进口TOC分析仪相近的分析精度及再现性 ,而该TOC分析仪的制造成本仅相当于进口仪器价格的 1 / 1 0～ 1 / 5 ,值得海洋、河流、湖泊等有关监测和研究部门借鉴。     

兰州市宛川河中段表层沉积物中重金属元素迁移富集特征

通过对兰州市宛川河中段双店子河段表层沉积物元素分析,结合有机质含量和粒度测试,运用聚类分析和相关分析的方法,研究了重金属元素在河流表层沉积环境中的分布及迁移富集等地球化学行为与特征。结果表明Zn元素在研究河段有轻度污染;相关分析表明重金属元素含量与沉积物粒度之间无显著相关性,重金属元素主要是在固-液平衡体系中、通过多相化学反应形成沉淀。污染源分析表明,造纸污水的排放是造成研究区域中上游河段有机质含量较高的主要原因,大分子有机物质的存在不仅改变了此段河流沉积物粒度的变化,且有机质对重金属元素的富集有一定减缓作用。