Effects of heavy metals (Pb2+ and Cd2+) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb2+ and Cd2+ (0, 0.5, 1, 2, 4, 6 and 8 mg/L). The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 ceils became evident with the increased (>4 mg/L Pb2+) metal concentration. The photosynthetic apparatus (thylakoid membranes) were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration (8 mg/L pb2+), the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations (0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L Pb2+), both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents (chlorophyll a, βcarotene and phycocyanin) were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb2+, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, β carotene and phycocyanin respectively over the control. Corresponding reductions for the same Cd2+concentrations were 57.83, 48.94 and 56.90%. Lethal concentration (96 h LC50) values (3.47 mg/L Cd2+ and 12.11 mg/L Pb2+) indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd2+ than Pb2+.     

章丘地区土壤硒的含量分布及影响因素

以章丘地区土壤为对象,系统分析了表层、深层土壤及8条剖面土壤中Se元素的含量水平,研究了土壤中Se的分布特征及其与土壤类型、成土母质、地形地貌和土壤理化性质及组分的关系。结果表明：章丘地区表层土壤中Se含量在0.1～0.8mg/kg之间,以中硒土壤为主,富硒土壤面积173km2。土壤类型中,水稻土Se平均含量水平最高,为0.55mg/kg;成土母质中以石炭—二叠纪泥页岩发育的土壤Se含量最高;剖面土壤中的Se主要在表层富集。影响章丘地区土壤Se含量分布的主要因素是成土母质、地形地貌、土壤pH、有机质及土壤中硫、铁铝氧化物等组分。     

珠江三角洲环境梯度上葫芦藓中硫、氮含量 和δ13C、δ15N的差异及其环境指示

以华南地区广泛分布的葫芦藓为研究对象,以珠江三角洲环境梯度上的中心城区广州、近郊区肇庆及边缘区怀集3个地理单元作为样品采集地,对样本葫芦藓植物中的硫、氮元素含量和δ13C、δ15N的组成进行了研究。结果表明：葫芦藓植物中硫含量与工业化程度表现出正相关关系,其中硫含量广州、肇庆和怀集依次为2 485.86、1 778.15、1 339.84 mg/kg;葫芦藓氮含量与工业化程度表现出正相关关系,广州、肇庆和怀集依次为 2 106.50mg/kg、2 007.39mg/kg和1 661.88 mg/kg;葫芦藓的C/N值与交通量呈负相关关系,其中C/N值广州为18.377,肇庆18.513,怀集23.905,3地C/N值大小差异揭示了从广州到怀集的环境梯度上,大气氮的主要组份发生了变化,即广州大气中的氮元素来源以工业排放的NOx-N（硝态氮）为主,怀集大气中的氮元素来源以农业排放的NHx-N（铵态氮）为主。     

Modelling hourly evapotranspiration and soil water content at the grass-covered boundary-layer field site Falkenberg,Germany

Abstract

The study analyses a 2-year period of hourly rates of real evapotranspiration (ETr) derived from eddy covariance measurements and soil water contents at depths from 8 to 90 cm, monitored by time domain reflectometry probes at the grass-covered boundary-layer field site Falkenberg of the Lindenberg Meteorological Observatory – Richard-Aßmann-Observatory, operated by the German Meteorological Service (DWD). The ETr rates and soil water contents were compared with the results of a modelling approach consisting of the Penman-Monteith equation and the soil water balance model Hydrus-1D using a noncompensatory and a compensatory root-water uptake model. After optimization of soil hydraulic parameters by inverse modelling, using measured soil water contents as the objective function, simulated and measured model outputs showed good agreement for soil water contents above 90 cm depth and for ETr rates simulated by our modelling approaches using noncompensatory root-water uptake. The application of a compensatory root-water uptake model led to a decrease in the simulation quality for the total investigation period.

Editor Z.W. Kundzewicz

Citation Wegehenkel, M. and Beyrich, F., 2014. Modelling of hourly evapotranspiration and soil water content at the grass-covered boundary-layer field site Falkenberg, Germany. Hydrological Sciences Journal, 59 (2), 376–394.     

瑞士的山地灾害研究

瑞士位于阿尔卑斯山脉地区,培内崩塌、滑坡、泥石流等山地灾害型齐全。该国政府十分重视保护生态环境,使山地灾害得到了有效控制。该文主要介绍瑞士从事从地灾害研究的机构手段、方法以及研究的内容。     

The ecology of Lerista labialis (Scincidae) in the Simpson Desert: reproduction and diet

This study investigated the diet and reproductive cycle of the southern sandslider skink Lerista labialis, in the dunefields of the Simpson Desert, central Australia. We dissected preserved specimens to obtain gut contents and measure gonad volume, and also live-captured animals from 1999 to 2000 to assess the impact of rainfall on population structure and body condition. This skink breeds during the austral summer. Males start spermatogenesis in July and testes volume is largest in December. Females have enlarged ovarian follicles in November and produce oviducal eggs from November to February. One or more clutches of two eggs are produced per breeding season. L. labialis specializes on termites, which represent 78% of the diet by percentage occurrence. The remaining 22% of this skink's diet comprises Hemiptera, Neuroptera and unknown prey items. Body condition, and probably increased reproduction and juvenile survival, were higher in 2000 (wet year) than 1999 (relatively dry year); proportion of juveniles also increased in the population in autumn, winter and summer 2000 compared to the previous year. Late rainfall in autumn 2000 may have triggered these demographic changes by increasing prey accessibility. Long-term research is required into growth rates, longevity and inter-annual population dynamics of L. labialis to fully evaluate its life history strategy.     

The use of molluscs for monitoring trace elements in the marine environment in New Zealand 1. The contribution of ingested sediment to the trace element concentrations in New Zealand molluscs

Reference elements, such as silicon, were used to calculate the effect of sediment in the gut contents of molluscs on the estimation of the total body burden of trace elements. A significant proportion of the aluminium, iron, manganese, and lead are contributed by the sediment in the gut of many New Zealand mollusc species. Local mineralisation is likely to produce an important contribution for elements such as chromium, vanadium, and nickel in some areas of New Zealand and the ingested sediment in molluscs from “clean” environments will result in the real body burden of some elements such as lead being naturally lower than the available data suggests.     

土壤表层与深层元素含量比值系数研究

通过研究元素含量在土壤表层和深层的比值,可以了解土壤表层元素含量的富集特征、成因和对环境的影响.将土壤中部分元素表层含量与深层含量进行了对比,统计、研究了比值系数及其分布特征,并对元素Cd区域性富集特征进行了探讨.指出成土母岩、元素化学特性、pH值、人类活动等对土壤中元素含量的富集具有重要的影响作用,应以地质、地球化学、人类活动等综合因素来研究土壤中元素含量的变化.     

21世纪工程地质学生长点：土体微结构力学

本文认为土体结构对其工程性质有重要制约作用,土的结构性模型的建立已成为当代土力学前沿性课题。提出的“微结构力学”理论与方法体系的建立,将为土体工程地质研究开辟崭新的研究领域和工作空间。文中,作者对“微结构力学”的概念及其研究内容、近期和远期研究课题进行了分析,并提供了开展本项研究工作的技术路线建议。     

现代水产种业硅谷建设的几点思考

"国以农为本,农以种为先",种业位于农业产业链的最前端,是国家战略性、基础性产业,也是决定现代农业发展的核心要素。我国是世界上12个生物多样性特别丰富的国家之一,水产种质资源分布极为广泛。近年来,我国水产种业发展迅速,但水产增养殖业的良种覆盖率仍然较低。因此,加快发展水产种业尤显迫切。该文论述了国内外水产种业发展现状,分析了我国水产种业存在的问题和发展趋势,提出了建设水产种业硅谷的设想,并对建设目标、建设内容、建设原则及其保障措施提出了几点建议,以期为我国水产种业健康发展起到积极的促进作用。