A flow cytometer based protocol for quantitative analysis of bloom-forming cyanobacteria (Microcystis) in lake sediments

A quantitative protocol for the rapid analysis of Microcystis cells and colonies in lake sediment was developed using a modified flow cytometer, the CytoSense. For cell enumeration, diluted sediment samples containing Microcystis were processed with sonication to disintegrate colonies into single cells. An optimized procedure suggested that 5 mg dw (dry weight)/mL dilution combined with 200 W × 2 min sonication yielded the highest counting efficiency. Under the optimized determination conditions, the quantification limit of this protocol was 3.3×10⁴ cells/g dw. For colony analysis, Microcystis were isolated from the sediment by filtration. Colony lengths measured by flow cytometry were similar to those measured by microscopy for the size range of one single cell to almost 400 μupm in length. Moreover, the relationship between colony size and cell number was determined for three Microcystis species, including Microcystis flos-aquae, M. aeruginosa and M. wessenbergii. Regression formulas were used to calculate the cell numbers in different-sized colonies. The developed protocol was applied to field sediment samples from Lake Taihu. The results indicated the potential and applicability of flow cytometry as a tool for the rapid analysis of benthic Microcystis. This study provided a new capability for the high frequency monitoring of benthic overwintering and population dynamics of this bloom-forming cyanobacterium.     

生物水解（酸化）法处理高浓度洁霉素废水的降解机理研究

在应用生物水解（酸化）法处理高浓度洁霉素生产废水中试试验中,着重研究水解（酸化）反应中起主要作用的微生物菌群及其降解效率。同时采用GPC（凝胶渗透色谱）、GC/MS（色谱一质谱）等分析手段对水解（酸化）反应过程中有机物形态变化进行研究。结果表明,在水解（酸化）反应中起主要作用的有埃希氏菌属、发酵单胞菌属、气单胞菌属、变形杆菌属、柠檬酸杆菌属等。同时,水解（酸化）反应具有将洁霉素废水中的大分子有机物降解为小分子有机物的作用,可提高废水的可生化性。     

浅水湖泊(阳澄湖)沉积物氨氧化菌的分子证据

选择长江三角洲中型浅水湖泊--阳澄湖,应用分子生物学方法鉴定淡水系统底质中的厌氧氨氧化细菌和好氧氨氧化细菌.试验设计三组厌氧氨氧化特异性巢式引物,对沉积物细菌的16S rRNA进行特异性扩增.其中,引物对AMX368f-AMX820r从底质中扩增出了anammox特异性序列,系统发育分析表明样品序列分别与Candidatus brocadia fulgida、Candidatus brocadia anammoxidans和Candidatus scalindua属近似.应用amoA基因特异性探针在底质中扩增出的好氧氨氧化菌序列,均属于Betaproteobacteria.本研究提供了阳澄湖中好氧氨氧化菌与厌氧氨氧化菌共存的分子证据.     

寒旱区草原湖泊沉积物重金属地球化学基线构建——以达里诺尔湖为例

为了科学识别寒旱区典型草原湖泊——达里诺尔湖的沉积物重金属累积状况,在调查表层及柱状沉积物重金属含量的基础上,采用多种统计学方法构建了沉积物重金属地球化学基线,并针对构建结果进行了多方面比较分析.结果表明,Cr、Ni、Cu、Zn、As、Cd、Hg、Pb在表层及柱状沉积物中均呈正态分布或对数正态分布,其中,柱状沉积物中的重金属分布较表层更为集中,且As、Cd、Hg在近表层呈现较明显的增长趋势,表明存在一定的表层富集;使用参考元素法、相对累积频率法和迭代2倍标准差法构建的表层、柱状沉积物重金属基线值之间无显著差异（P<0.05）,综合考虑科学性,适用性,简便性,人为误差性等方面,可优先选取迭代2倍标准差法进行元素基线构建;研究构建的达里诺尔湖沉积物重金属基线值与所在区域的大尺度土壤背景值相比存在差异,且表层与柱状沉积物基线值也存在差异,考虑到达里诺尔湖流域人为干扰极小,使用研究区域的表层沉积物开展基线值构建,可为识别湖泊当前重金属富集状况和生态风险提供更为科学和准确的参考依据.研究结果可为类似的寒旱区草原湖泊沉积物重金属基线值构建提供理论依据.     

Integrating geochemical (surface waters, stream sediments) and biological (diatoms) approaches to assess AMD environmental impact in a pyritic mining area: Aljustrel (Alentejo, Portugal)

Aljustrel mines were classified as having high environmental hazard due to their large tailings volume and high metal concentrations in waters and sediments.To assess acid mine drainage impacted systems whose environmental conditions change quickly,the use of biological indicators with short generation time such as diatoms is advantageous.This study combined geochemical and diatom data,whose results were highlighted in 3 groups:Group 1,with low p H(1.9–5.1)and high metal/metalloid(Al,As,Cd,Co,Cu,Fe,Mn,Ni,Pb,Zn;0.65–1032 mg/L)and SO_4(405–39124 mg/L)concentrations.An acidophilic species,Pinnularia aljustrelica,was perfectly adapted to the adverse conditions;in contrast,teratological forms of Eunotia exigua were found,showing that metal toxicity affected this species.The low availability of metals/metalloids in sediments of this group indicates that metals/metalloids of the exchangeable fractions had been solubilized,which in fact enables metal/metalloid diatom uptake and consequently the occurrence of teratologies;Group 2,with sites of near neutral p H(5.0–6.8)and intermediate metal/metalloid(0.002–6 mg/L)and SO_4(302–2179 mg/L)concentrations;this enabled the existence of typical species of uncontaminated streams(Brachysira neglectissima,Achnanthidium minutissimum);Group 3,with samples from unimpacted sites,showing low metal/metalloid(0–0.8 mg/L)and SO_4(10–315 mg/L)concentrations,high pH(7.0–8.4)and Cl contents(10–2119 mg/L)and the presence of brackish to marine species(Entomoneis paludosa).For similar conditions of acidity,differences in diversity,abundance and teratologies of diatoms can be explained by the levels of metals/metalloids.     

富营养化巢湖沉积物溶解性有机质光谱时空分布特征及其环境意义

通过紫外吸收光谱（UV-vis）和三维荧光光谱（3D-EEMs）,研究典型富营养化湖泊巢湖沉积物溶解性有机质（DOM）光谱时空分布特征.结果表明,巢湖表层沉积物DOM的a（254）含量为13.1~101.7 m^-1,平均值为（32.2±16.2）m^-1.其中,夏季沉积物a（254）的含量（（46.6±25.6）m^-1）要显著高于其它季节,且湖心区a（254）平均值和变异性均小于湖滨区.表层沉积物DOM的S_275~295值从春季到冬季上随时间呈明显上升趋势.沉积物DOM荧光强度在夏季最高,在垂直剖面上总体呈下降趋势.DOM组分以酪氨酸类蛋白质和溶解性微生物产物为主,各组分在空间分布上无明显差异.巢湖沉积物DOM荧光指数（FI）为2.56~4.89,腐殖化指数（HIX）为0.57~6.78,生物源指数（BIX）为0.31~1.54.巢湖沉积物DOM主要来自于生物源,藻的生长循环会显著影响富营养化湖泊沉积物DOM的来源和性质.     

巢湖沉积物有效态磷与硫的DGT原位同步分析研究

沉积物有效态磷(P)与硫(S)的含量分布是影响湖泊营养元素循环和水体富营养化的重要因子.本文利用Zr O-Ag I薄膜梯度扩散技术(Zr O-Ag I DGT)原位同步获取了南淝河-巢湖沉积物中有效态P和S的高分辨分布信息.结果发现:绝大部分沉积物有效P和S自界面向下呈急剧升高趋势,并在50 mm深度内出现峰值;河道内沉积物有效P和S的含量高于湖体,且P在界面的表观释放通量明显高于湖体,表明河道沉积物是湖体P的输入源.部分采样点出现有效P与S同步变化的现象,两者具有显著相关性,证实沉积物内部P和S存在同步释放的规律.     

巢湖沉积物磷铁硫形态记录及其环境变化指示

分析了巢湖表层和柱状沉积物中磷(P)、铁(Fe)和硫(S)元素的形态组成、分布、相互关系及其指示的湖泊环境变化.西半湖S3采样点位柱状沉积物总磷(TP)记录表明,巢湖西半湖区自20世纪60年代开始受人类活动影响逐步明显,其中钙磷(Ca-P)指示的流域径流输入增加早于铁铝磷(Fe/Al-P)指示的居民生活污水输入;西半湖...     

基于液相31P核磁共振技术的不同地理区域湖泊沉积物生物质磷(Biogenic-P)形态特征研究

利用液相~(31)P核磁共振分析方法,研究了我国不同地理区域湖泊表层沉积物中生物质磷(Biogenic-P)的形态特征.结果表明,不同地理区域湖泊表层沉积物磷含量差异较大,湖泊沉积物中的总磷在184.37～1089.41 mg·kg~(-1)之间,青藏高原的青海湖总磷含量最高,达到1089.41 mg·kg~(-1).使用~(31)P-NMR技术在湖泊沉积物中共检测到4类磷化合物,其中生物质磷检测到3类磷化合物,分别为:磷酸单酯(Mono-P)、DNA磷(DNA-P)、焦磷酸盐(Pyro-P),其中以磷酸单酯为主,含量在5.57～399.18 mg·kg~(-1)之间.随着我国外源性磷的有效控制,内源性磷成为了磷主要的来源,在磷的内源负荷中,生物质磷矿化释放的磷将会影响水体整体生产力,本研究基于液相~(31)P核磁共振技术,对我国不同区域湖泊沉积物中磷形态的分布有了一些新的认识,可为深入认识磷在不同区域湖泊中转化提供支持,有助于深入研究不同区域湖泊磷生物地球化学循环过程,同时为认识我国不同区域湖泊沉积物中磷形态特征提供数据支持.     

Phosphorus fractionation and bio-availability in Taihu Lake(China) sediments

Introduction Sediment phosphorus has been recognized as the mostcritical nutrient limiting lake productivity (OECD, 1982).The concentration of phosphorus in the sediment is often1000 fold higher than that in lake water and its release…     

A pilot scale anoxic/oxic membrane bioreactor (A/O MBR) for woolen mill dyeing wastewater treatment

A pilot-scale( 10 m^3/d) anoxic/oxic membrane bioreactor( A/O MBR) was tested for dyeing wastewater treatment of woolen mill without wasting sludge in 125 days operation. Results showed that the effluent quality was excellent, i.e. effluent COD less than 25 mg/L,BOD5 under 5 mg/L, turbidity lower than 0.65 NTU, and colour less than 30 DT, and met with the reuse water standard of China. The removal rates of COD, BOD5, colour, and turbidity were 92.4%, 98.4%, 74% and 98.9%, respectively. Constant-flux operation mode was carried out in this study, and backwash was effective for reducing membrane fouling and maintaining constant flux. Membrane fouling had heavy impact on energy consumption. More attention should be paid on pipe selection and design for the sidestream MBR system, too.     

A 50-year record of dichloro-diphenyl-trichloroethanes and hexachloro-cyclohexanes in lake sediments and penguin droppings on King George Island, Maritime Antarctic

Since the ban on the use of organochlorine pesticides （OCPs） such as dichloro-diphenyl-trichloroethane （DDT） and hexachlorocyclohexane（HCH） in agriculture, their levels have generally dropped. In a number of cases, however, the levels of these OCPs were found to be unchanging or even increasing after the ban. With the aim to unveil the possible causes of these exceptions, we collected two lake cores from King George Island, West Antarctica, and determined their accumulation flux profiles and temporal trends of these OCPs. In the lake core sediments with glacier meltwater input, the accumulation flux of DDT shows an abnormal peak around 1980s in addition to the expected one in 1960s. In the lake core sediments without glacier meltwater input, the accumulation flux of DDT shows a gradual decline trend after the peak in 1960s. This striking difference in the DDT flux profiles between the two lake cores is most likely caused by the regional climate warming and the resulted discharge of the DDT stored in the Antarctic ice cap into the lakes in the Antarctic glacier frontier. Furthermore, to investigate the change of OCPs loadings in the Antarctic coastal ecosystem, we reconstructed the HCH and DDT concentration profiles in penguin droppings and observed a gradual increase for the former and a continuous decrease for the latter during the past 50 years. The increase of HCH seems to be due to the regional warming from the early 1970s and the resulted HCH discharge to the coastal ecosystem by glaciers＇ meltwater and the illegal use of HCH in the Southern Hemisphere in the recent decade. The different temporal trends of HCH and DDT accumulation rate in the lake core with glacier meltwater input and the aged penguin droppings can be explained by their different water-soluble property.     

基于支持向量机的湖泊生态系统健康评价研究

利用支持向量机在处理分类问题、小样本问题和泛化推广方面的优势,构建了基于支持向量机的湖泊生态系统健康评价模型.同时,对广州市最大的人工湖——白云湖的水质及生物群落情况进行了监测,最后运用该模型对白云湖生态系统健康状况进行了评价.评价结果表明,白云湖生态系统处于病态状态,不能达到其净化水质的设计作用.建议从提高进水水质、实施湖区截污和丰富生物量3方面改善白云湖生态系统健康水平.与传统熵权综合健康指数法和熵权模糊综合评价法相比,所建模型更加客观、科学地评价了湖泊生态系统健康状况,能够为湖泊生态系统健康管理提供一定依据,具有广阔的应用前景.     

铊在河流沉积物上的吸附解吸行为研究

水体环境条件的改变直接影响铊在水体沉积物的吸附解吸行为,进而影响到铊在水环境中的迁移、转化途径.本实验采用北京市凉水河(L8)及其沿岸的藕田(L6)沉积物作为研究对象,研究了Tl(Ⅰ)在沉积物上的吸附特征及pH对其吸附过程的影响,并考察了以沉积物浸出液和背景电解质作为解吸体系时,Tl(Ⅰ)自沉积物上解吸的变化情况.研究结果表明:①两种沉积物对铊的吸附速度较快,初始的5 min内,沉积物对铊的吸附量达到最大吸附量的90％ (L6)和80％(L8)以上,12h基本达到吸附平衡.②沉积物L6和L8对Tl(I)吸附量均随着初始浓度的升高而增大,但是L6的吸附量明显高于L8.两种沉积物对铊的吸附等温线用Freundlich方程和Langmuir方程拟合均得到较好的拟合结果,在分析吸附解吸机理时,Langmuir方程更能说明其物理化学意义.③pH对铊在沉积物上的吸附影响较大,随着体系pH的增大,吸附量逐渐增大.④沉积物浸出液的高效体积排阻色谱和三维荧光表征结果表明沉积物浸出液中主要以类蛋白和腐殖酸类物质为主,荧光强度集中在1100 ～1550之间.用沉积物浸出液代替背景电解质作为解吸体系时,解吸量增加了2.232 mg·kg-1(L6)和1.494 mg·kg-1(L8)(C0 =0.33 mg·L-1),铊更易从沉积物浸出液的环境下解吸下来,进入水体.     

The relationship between the black carbon and bisphenol A in sea and river sediments (Southern Baltic)

This study was derived from field investigations to assess bisphenol A (BPA) concentrations in the sea and river sediments of the Gulf of Gdansk. Black carbon (BC) and total organic carbon (TOC) were identified as influencing factors on the accumulation. As a result of the transportation of BC with organic matter via rivers into the Gulf of Gdansk, the highest mean concentrations (11.26 ng BPA/(g dry weight (dw))), were determined in the sediments of river estuaries. Sediments in coastal stations were characterized by the lowest mean concentrations (5.73 ng BPA/(g dw)). TOC content below 0.1% determined the sorption of BPA on BC particles in sediments, and statistically significant correlation between the concentration of BPA and the BC/TOC ratio was found in these cases. In addition, dependency between the concentration of BPA and the content of BC was discovered in sediments where the BC/TOC ratio was > 0.33.     

A review of myrmecophily in ant nest beetles (Coleoptera: Carabidae: Paussinae): linking early observations with recent findings

Myrmecophily provides various examples of how social structures can be overcome to exploit vast and well-protected resources. Ant nest beetles (Paussinae) are particularly well suited for ecological and evolutionary considerations in the context of association with ants because life habits within the subfamily range from free-living and predatory in basal taxa to obligatory myrmecophily in derived Paussini. Adult Paussini are accepted in the ant society, although parasitising the colony by preying on ant brood. Host species mainly belong to the ant families Myrmicinae and Formicinae, but at least several paussine genera are not host-specific. Morphological adaptations, such as special glands and associated tufts of hair (trichomes), characterise Paussini as typical myrmecophiles and lead to two different strategical types of body shape: while certain Paussini rely on the protective type with less exposed extremities, other genera access ant colonies using glandular secretions and trichomes (symphile type). We compare these adaptations with other taxonomic groups of insects by joining contemporary research and early sources and discuss the possibility of an attracting or appeasing effect of the secretion. Species that are ignored by their host ants might use chemical mimicry instead. Furthermore, vibrational signals may contribute to ant–beetle communication, and chemical signals have proven to play a role in host finding. The powerful defense chemistry of paussines as “bombardier beetles” is not used in contact with host ants. We attempt to trace the evolution of myrmecophily in paussines by reviewing important aspects of the association between paussine beetles and ants, i.e. morphological and potential chemical adaptations, life cycle, host specificity, alimentation, parasitism and sound production.

Chorion biopsy in early pregnancy: A method of early prenatal diagnosis for inherited disorders

Chorion biopsy was performed in 165 cases at 6–12 weeks of pregnancy, following an ultrasonic or embryo-fetoscopic chorion frondosum localization. One hundred patients had their biopsies taken immediately before induced abortion. In 39 cases abortion was carried out 5–10 days after biopsy. In 26 pregnant patients biopsy was performed for genetic reasons. Fetal sex was determined in ‘native’ smears from biopsy specimens for cytological investigation, using X- and Y-chromatin assays. Fetal sex diagnosis proved correct in all the cases. In 40 observations, the origin of the biopsy specimen was histologically checked. In 16 biopsy specimens, a number of enzymes were simultaneously assayed: β-D-ghcosidase, β-D-galacto-sidase, β-D-hexosaminidase, β-D-glucuronidase, α-L-fucosidase, β-D-mannosidase, sphingo-myelinase and arylsulphatase A. The levels of the above enzymes were compared to those observed in tissue cultures of amniotic cells obtained through amniocentesis at 16–18 weeks of pregnancy. The amniotic sac remained intact in all cases of chorion biopsy. If the pregnancy was maintained after the biopsy, no spontaneous abortions were recorded, and pregnancies resulted in the timely delivery of full-term healthy infants. Therefore, the method described is a valuable means of diagnosing inherited disorders, with promising applications in prenatal medicine.