Multiplex PCR allows simultaneous detection of pathogens in ships' ballast water

There is enormous potential for global transfer of microorganisms, including pathogens, in ships' ballast water. We contend that a major advancement in the study of ballast-water microorganisms in particular, and of aquatic pathogens in general, will be expedited sample analysis, such as provided by the elegant technology of DNA microarrays. In order to use DNA microarrays, however, one must establish the appropriate conditions to bind target sequences in samples to multiple probes on the microarrays. We conducted proof-of-concept experiments to optimize simultaneous detection of multiple microorganisms using polymerase chain reaction (PCR) and Southern hybridization. We chose three target organisms, all potentially found in ballast water: a calicivirus, the bacterium Vibrio cholerae, and the photosynthetic protist Aureococcus anophagefferens. Here, we show simultaneous detection of multiple pathogens is possible, a result supporting the promising future use of microarrays for simultaneous detection of pathogens in ballast water.     

我国常用湖泊营养状态指数研究进展与展望

湖泊(包括自然湖泊和人工水库)富营养化已成为世界性的环境问题,营养状态指数是目前最流行的富营养化水平量化方法。然而,不同营养状态指数的基本逻辑和适用水体等方面存在明显差异,不当选取可能会造成营养水平和相关水华风险的错误估计,并引发湖泊保护和修复措施的错位。鉴于此,本文对我国常用营养状态指数的构建思路、共性和差异以及不确定性来源等进行了综述。总体来看,营养状态指数基本构建思路分3种:1) Carlson指数型(如TSI),以透明度(SD)为核心参数,使用SD的2倍变化对应指数的10分差值,假定SD 为64 m时记为指数值0分;2)改良TSI指数型(如TSIm),以叶绿素a(Chl.a)为核心参数,使用Chl.a的2.5倍变化对应指数的10分差值,假定Chl.a 1000 μg/L对应该指数100分;3)营养足迹指数型(如TFI),该指数亦使用Chl.a指示藻类生物量,Chl.a的e倍关系对应藻类生物量的二倍变化和指数10分差值,假定Chl.a为10 μg/L时对应该指数50分。根据上述假设得出对应的基础参数评估方程,然后均以基础参数(SD或Chl.a)与衍生参数间的经验方程 “直接替换”获得衍生参数的评估方程。如上可知,营养状态指数均体现了数值增大表征藻类初级生产力和伴随的水华风险提高的共性,同时本文也从:1)数据集属性和基础指标评估方程获取的方法;2)衍生指标评估方程获取的统计原理;3)分项指标的权重设置方式3个方面分析营养状态指数之间的差异性。未来展望方面,首先,鉴于当前营养状态指数均属于通用性指数,因而建议未来基于上述3种基本类型开发因地制宜的营养状态指数,实现湖泊藻类生产力和水华风险的精准指示;其次,营养状态指数的生态学依据是藻类限制因子理论,营养状态指数各分项指标(即基于总氮、总磷、SD和Chl.a)的差异可以指示初级生产力的限制因子,建议未来开展营养状态指数分项指标差异机制研究,以指导藻类水华防控措施精准施策;再次,除富营养化外,湖泊生态健康受损往往也与其它压力有关,建议未来开展湖泊生态健康对富营养化和其他压力的综合响应机制研究,制定服务于湖泊生态系统健康提升的精准调控路径。本文目的并非将营养状态指数的通用属性“复杂化”,而是旨在阐明营养状态指数的“前世今生”,进而为广大湖泊富营养化相关人员使用指数时提供参考,也希望为我国湖泊营养状态精准量化、后续保护和修复措施的精准实施提供科学依据。     

三峡水库小江回水区水华暴发期浮游植物群落结构及其与环境因子的关系

三峡水库蓄水以来,支流水华频发,尤以小江情况最为严重,给三峡库区的生态安全带来较大隐患。为探究支流水华暴发特征和主控因素,于2014-2021年小江水华暴发期间在小江高阳江段进行浮游植物及环境因子调查,并使用单因素方差分析、聚类分析、百分比相似性分析以及基于距离的线性模型等方法,对小江水华暴发期间浮游植物和环境因子在不同年份不同水层间的差异以及二者的关系进行研究。结果表明:小江水华暴发期内,浮游植物的种类数在43~70种之间,其中2015年蓝藻种类数明显减少,2018年以后硅藻种类数明显减少;采样期间浮游植物平均细胞密度在0.66×10⁶~61.28×10⁶ cells/L之间,同期表层细胞密度明显高于中层和底层;各层水体间水华微囊藻、铜绿微囊藻、不定微囊藻等10种藻的密度存在明显差异,是主要差异种;显著影响表层、中层和底层浮游植物群落结构变动的环境因子是水位的日平均变幅;水位的日平均变幅与藻类优势种拟合关系显示,当日水位下降幅度在0.5 m以上时,浮游植物平均密度会呈指数级减少。研究结果可为三峡库区支流水华的防控提供数据支持。     

Speciation of organic carbon,Cu and Mn in the River Marne (France): the role of colloids

The distribution of organic carbon (OC) and of some metals (Cu, Mn) amongst the particulate (>0·2 μm), colloidal (10 kDa–0·2 μm) and the truly dissolved (<10 kDa) fractions of the River Marne was investigated during the phytoplankton spring bloom. A tangential ultrafiltration (UF) device was utilized to separate the colloidal fraction. On average, 22% of the OC, 31% of the Cu and 53% of the Mn, usually assigned to the so‐called dissolved fraction, were found in the colloidal fraction. The colloidal fraction exhibited a behaviour different from that of the particulate and truly dissolved fractions. Autochthonous production led to enrichment in the colloidal and particulate OC pools: up to 47% of the total dissolved OC was in the colloidal fraction. An increase in the colloidal metal fraction, concomitant with a fall in the truly dissolved fraction, coincided with peaks in phytoplankton during the bloom. These phenomena might be related either to an increase in pH associated with photosynthetic activity, resulting in the precipitation of truly dissolved forms into the colloidal fraction, or to scavenging of the truly dissolved metals by the algal species of colloidal size. The interaction between the colloidal and the truly dissolved phases was very important. The partition coefficients of the Cu and Mn between the colloidal and truly dissolved fractions were higher than between the particulate and the truly dissolved fractions. This pattern is consistent with a greater specific surface area of colloids than macroparticles. Consequently, the adsorption and complexation capacities are enhanced in the colloidal fraction of the particulate matter. The extraction of hydrophobic complexes with Cu using C₁₈ Sep‐Pak columns, showed that the Cu occurring in colloidal, total dissolved or truly dissolved forms was significantly complexed by the organic matter. The truly dissolved fraction might be complexed up to 100% during a phytoplankton bloom. Copyright © 1999 John Wiley & Sons, Ltd.     

Lower carboniferous coal deposition environments on Spitsbergen, Svalbard

Two coal-bearing units from the Lower Carboniferous succession in Central Spitsbergen, Svalbard, have been investigated using coal petrographic and geochemical techniques. The upper member consists mainly of algal cannels, dominated by Botryococcus-type algae. The coals from the lower member are a mixture of durite-type coals with sporinite and inertinite and coals containing prdominantly vitrinite. The Rock-Eval and pyrolysis-GC also show a clear distinction in the composition of the organic matter in the two coal-bearing units investigated. These results, together with detailed sedimentological analyses, are used to reconstruct the depositional environments for the two coal-bearing sequences.     

The variations in optical properties of CDOM throughout an algal bloom event

For studies in bio-optical oceanography, visible light properties by classes of dissolved organic matter should be characterized. The regional adjustment of model parameters is one approach which is being widely used to refine bio-optical models. In the present study, buoy and laboratory data were acquired, and during the 15-day observation period an algal bloom event occurred. The absorption coefficient of CDOM at 443 nm, a_g(443), changed in the range of 0.09–0.35 m⁻¹ and 0.1–0.34 m⁻¹ for two depths, 0.32 m and 2.3 m., respectively, throughout the entire period. CDOM absorption was larger for bloom conditions than for non-bloom conditions. In addition, the fraction of CDOM in total absorption was higher during the bloom event than that of non-bloom conditions. The spectral slope of CDOM absorption, S_g, regressed over 400–500 nm, ranged from 0.015 to 0.0185 nm⁻¹ with an average of 0.0166 nm⁻¹. CDOM fluorescence intensity (Fcdom) was obtained using an internal Raman standard and varied over the range of 467.44–1538.23 in relative units. Variations in Fcdom showed a similar pattern to that of CDOM absorption. A robust non-linear relationship between Fcdom and CDOM absorption was found, with a correlation coefficient of 0.893, throughout the whole observation. An attempt to describe S_g with absorption showed a promising consequence that can be described with a negative correlation during the bloom, however, without any distinguishable tendency for non-bloom time span. A two-band ratio algorithm was also carried out for retrieving CDOM absorption. The variations in optical properties of CDOM may be related to the complicated environment in the estuarine waters, which may result from different sources of CDOM.     

绿潮生物学机制研究

绿潮发生机制极其复杂,但其核心机理是绿潮暴发时漂浮"藻席"中的浒苔快速形成巨大生物量,涉及浒苔生物学过程对环境的响应及其生理生化基础。为此,本文在已有研究报道的基础上,对浒苔生活史研究进行了充分的理论补遗;分析了漂浮"藻席"中浒苔生长与繁殖过程,认为该过程是绿潮生物量形成的关键;阐述了浒苔孢子囊形成是对富营养化背景下海水溶解无机氮(DIN)中硝态氮高占比的响应,认为一氧化氮分子可促进浒苔营养细胞向孢子囊的转化;解析了浒苔细胞对逆境因子的响应途径与机制。基于已有的研究成果,本文对浒苔引发绿潮的生物学过程进行了理论推定。人为或自然因素使固着浒苔处于漂浮状态,形成小规模"藻席";富营养化背景下海水DIN中硝态氮占比的升高赋予了浒苔巨大的繁殖潜能,漂浮过程溶解无机碳(DIC)"充裕"和"不足"两个阶段的交替以及食藻动物啃食产生的藻片段使孢子囊形成比例大幅提升;孢子原位萌发等使释放的孢子在"藻席"中获得了附着基,个体数目随之指数增长;结合漂浮浒苔的高生长速率,"藻席"规模不断扩大,短时间内形成巨大生物量。同时,本文还对今后的绿潮研究提出一些建议,认为啃食动物在浒苔生物量消长过程中发挥重要作用,在...     

燕辽地区中、晚元古代宏观藻类化石研究

以蓟县中、上元古界层型剖面所产宏观藻类化石为重点,兼顾京冀辽等邻区,全面总结和系统讨论了该区中、晚元古代宏观藻类化石的研究简史、产出层位、区域分布、化石组合、生物群特征、可能的系统分类,以及国内外对比与地层学意义,初步探讨了宏观藻类植物群在中、新元古代的发生、发展与更迭,追索宏观真核生物起源等.通过对燕辽地区中、新元古代宏观藻类的研究与总结,把显生宙行之有效的生物地层学方法运用于前寒武纪地层研究中,进行国内外前寒武纪地层的对比,显然具有重要的地层学意义.同时,对探讨地球早期生命演化也具有重要的理论意义.     

川黔地区地表钙华中发现现代淡水叠层石及藻席

笔者通过对四川九寨沟、贵州黄果树、马岭河峡谷以及香纸沟的地表钙华的考查和研究,首次在地表钙华体中发现现代淡水叠层石及其藻席,并总结了研究区叠层石藻席的种类和特征,认为该研究区叠层石藻席中微生物群落的优势种主要属于蓝藻门中的裂须藻属（Ｓｃｈｉｚｏｔｈｒｉｘ）、席藻属（Ｐｈｏｒｍｉｄｉｕｍ）和鞘丝藻属（Ｌｙｎｇｂｙａ）。该叠层石的形成是由于蓝藻藻席的新旧更迭以及沉积物的周期性沉积造成的;叠层石的纹层和     

几种海藻粗多糖的理化性质及结构特征分析

主要采用傅里叶红外光谱(fourier transform infrared spectroscopy, FTIR)、气相色谱(gas chromatography, GC)和凝胶渗透色谱(gel permeation chromatography, GPC)方法对5种海藻粗多糖的单糖组成、官能团、分子量进行了初步分析。结果显示5种海藻粗多糖均含有木糖和岩藻糖, 其中南方团扇藻多糖含有较为丰富的山梨糖, 属于大分子量均一性多糖, 而孔石莼多糖分子量分布较宽, 均一性较差。红外光谱分析结果表明, 5种粗多糖均为酸性多糖, 棒叶蕨藻、琼枝麒麟菜和匍枝马尾藻多糖具有明显的硫酸基团吸收峰, 琼枝麒麟菜多糖存在呋喃糖和吡喃糖, 并且吡喃糖苷键可能存在β和α两种类型。明胶氯化钡实验结果指出南方团扇藻多糖的硫酸基团含量为38.43%(±2.38%), 明显高于其他几种海藻多糖, 而棒叶蕨藻多糖的硫酸基团含量最低, 仅为8.92%(±1.04%)。