水电梯级开发对乌江流域浮游植物分布的影响

调查研究了乌江流域贵州段5个水库上游来水、库区、坝下浮游植物的种类、密度和生物量,结果显示,库区较电站上游来水浮游植物种类增加,其中绿藻门、蓝藻门种类增加较多,硅藻门种类仍然是水库库区的主要种类,库区浮游植物密度和生物量分别为上游来水的2.06倍和1.77倍。库区浮游植物数量的增加幅度与水库调节能力、水体营养负荷及库区周边环境等因素有关。索风营水库为日调节型水库,水文情势较原河流变化较小,库区浮游植物增加幅度较小,而洪家渡水库为多年调节水库,水文情势的变化差异很大,库区浮游植物密度和生物量较上游来水显著增加。     

罗非鱼密度对养殖池塘浮游植物群落结构的影响

在养殖水体中,养殖动物与浮游植物的群落结构有着重要的联系,该实验通过对不同养殖密度罗非鱼养殖池塘进行了连续的采样调查,进而对浮游植物的种类、密度、生物量、多样性指数、优势种等进行了分析研究,讨论并分析了罗非鱼的密度对浮游植物群落结构的影响。罗非鱼单养池塘5次采样共鉴定出蓝藻、硅藻、裸藻、隐藻、甲藻、绿藻6门92种(包括变种)浮游植物;其中蓝藻门16种,硅藻门16种,裸藻门7种,隐藻门3种,甲藻门1种,绿藻门49种。低密度养殖浮游植物总密度在1 562.5×10~4~22 660.5×10~4cells/L之间,生物量在7.92~24.15 mg/L之间;中密度养殖浮游植物总密度在1 575×10~4~20 390×10~4cells/L之间,生物量在11.78~25.17 mg/L之间;高密度养殖浮游植物总密度在1 422.5×10~4~20 351×10~4cells/L之间,生物量在7.25~20.04 mg/L之间。不同密度组浮游植物总密度差异不显著,生物量差异不显著(P0.05),表明在该实验密度条件下,罗非鱼密度对浮游植物的密度和生物量影响较小。高密度罗非鱼养殖池塘的浮游植物最高密度出现的时间比中密度和低密度要早,且较早达到稳定水平,表明高密度罗非鱼养殖会增大浮游植物密度增长速率,加快池塘浮游植物群落结构的演变。     

基于光合色素的海南八门湾及其毗邻水域浮游植物生物量及类群组成研究

根据2010年4月（春季）、2011年8月（夏季）在海南八门湾及其毗邻水域的采样调查，采用CHEMTAX化学分类法对该区域的表层水的浮游植物生物量以及类群进行了研究。初步的研究结果表明:春季，生物量由湾内向外海增大，最高值出现在文昌河入八门湾处，金藻、硅藻为主要优势类群。生物量与溶解无机氮（DIN）、SiO₃2-、PO₄3-正相关，与盐度负相关，浮游植物与营养盐比值（N:P，Si:N）相关性不明显，硅藻与P显著正相关。夏季，生物量空间分布差异较小，最高值出现在文教河，蓝藻、金藻、硅藻为优势类群。浮游植物生物量及群落结构特征与营养盐含量和比值之间存在相关性。生物量与SiO₃2-正相关，与盐度负相关，绿藻与N:P比呈正相关关系，绿藻还同时与N正相关，硅藻与Si:N比正相关。     

海洋浮游植物对磷限制的响应机制

海洋浮游植物是全球初级生产力的重要贡献者,它们的生物量主要受到氮、磷、铁等营养元素的限制。磷元素作为浮游植物所必需的元素,在寡营养海域的真光层海水中十分缺乏,是浮游植物生长的限制因子。磷元素的缺乏不仅直接影响浮游植物的生长繁殖及物种演替,还对海洋碳、氮生物地球化学循环产生深远影响。全球变暖加剧海水层化,进而减少垂直混合带来的营养盐补充。面对不断变化的海洋环境,浮游植物通过减缓细胞生长、加强磷吸收和储存、分解有机磷、磷脂替代、降低细胞对磷酸盐的依赖等方式,应对海洋环境中的磷限制。本文总结了近年来海洋浮游植物应对磷限制响应机制的最新研究进展,主要从生理响应和生态效应方面综述了海洋磷限制对浮游植物的影响以及浮游植物响应海洋磷限制的策略,希望对海洋浮游植物和海洋环境科学相关研究具有借鉴意义。     

南四湖浮游植物多样性与群落生物量、时间序列稳定性关系

基于2011到2014年对南四湖浮游植物进行的连续监测,研究浮游植物多样性(物种组成和均匀度)与生物量和群落稳定性的关系.结果表明,调查期间共鉴别出浮游植物8门78属138种.湖泊浮游植物细胞密度在5.09×10~5个/L到6.95×10~6个/L之间变化,生物量在0.44mg/L到5.46mg/L之间变化.在温度较低的春季和冬季,浮游植物生物量随着物种数的增加而增加,多样性高的群落有更高的生产力.在夏季,浮游植物生物量随着物种数的增加而降低,多样性高的群落具有相对较低的生物量.蓝藻、硅藻和总浮游植物稳定性指数与浮游植物物种数均呈单峰关系.浮游植物均匀度与各个群落稳定性指数的相关系数均不显著.这些结果表明,浮游植物多样性与群落生物量和稳定性有比较复杂的关系:物种数与生物量呈线性关系且受季节变化的影响,与稳定性呈单峰曲线关系;均匀度指数与生物量和稳定性都没有显著的关系.     

2005—2007年阳宗海浮游植物生物量变化特征分析

对2005—2007年阳宗海浮游植物生物量数据进行了监测分析。结果显示:浮游植物生物量总体呈下降趋势;浮游植物平均生物量在水体中空间分布呈现差异性分布,中部北部南部;中部和北部浮游植物生物量变化较大,南部变化较小;湖泊水体目前处于中营养状态。     

富营养水体浮游植物群落对新型生态浮床的响应

通过围隔水泥池模拟试验,研究了富营养化水体中浮游植物群落对新型组合型生态浮床系统净化水质的响应. 每隔2周对水体中各水质指标、浮游植物及浮游甲壳动物群落进行检测,结果显示:①3种不同覆盖率(以浮床面积计)处理下,组合型生态浮床对氮、磷的去除率表现为39%覆盖率>26%覆盖率>13%覆盖率. ②3种覆盖率下水体中的浮游植物群落结构复杂性和生物多样性指数均显著高于空白对照组,其中,26%和13%覆盖率对浮游植物生物量的抑制效果比39%覆盖率好;同时,26%覆盖率比39%覆盖率水体中的浮游植物生物多样性指数要高,群落结构更复杂,随后是13%覆盖率处理. ③浮游植物生物量的变化与浮游甲壳动物表现出明显的相反时间趋势. 尽管26%覆盖率对氮、磷的去除量不是最大,但却更利于形成较为稳定的浮游植物群落结构,促进水体生态系统的平衡与健康发展;浮游植物生物量与营养盐的显著相关性及与浮游甲壳动物的相反时间趋势显示,生态浮床对浮游植物群落的改善可能是通过营养盐的上行效应与浮游甲壳动物的下行效应等因素得以实现.      

苏南水库硅藻群落结构特征及其控制因素

为了解我国东南湿润区丘陵山地型水库硅藻的群落结构特征和控制因素,于2015年6月硅藻水华敏感期对苏南地区18座水库的浮游植物群落结构和水质进行调查,分析了营养盐、水深、库容等因素与硅藻及其它浮游生物的关系.结果表明,硅藻达到轻度水华水平(硅藻细胞含量介于100~1 000万cells·L~(-1))的水库有10座,对供水和景观功能产生明显影响;苏南地区水库普遍处于中营养和富营养水平,总氮浓度普遍偏高,磷及营养状态指数与硅藻生物量的关系密切;苏南地区水库中的浮游植物在数量上以蓝藻门中的席藻为主,在生物量上则以硅藻门、绿藻门和蓝藻门为主,其中硅藻门浮游植物平均占总浮游植物生物量的46.8%,是浮游植物异常增殖的主要门类;硅藻门中,主要是针杆藻、小环藻、曲壳藻和直链藻这4个种属占优,特别是针杆藻和小环藻,平均占硅藻总生物量的51.6%和21.4%;较深的水体,利于硅藻成为主要优势藻门;较大的水库流域库容比和较高总磷水平会导致水库营养水平和叶绿素浓度增加,促进浮游植物从硅藻门向绿藻门、蓝藻门演替,增加藻类危害的风险.因此,对于该地区水库,需要加强流域管理,并且针对水库自身的特点,包括水深、流域库容比等,确定其特定的富营养化控制策略,从而减少硅藻等藻类水华发生的风险,提升水源地水质安全保障能力.     

宁夏沙湖浮游植物与水环境因子关系的研究

于2009年4月～2010年1月测定了沙湖浮游植物的密度、生物量和叶绿素a含量,测定了水温(WT)、pH、透明度(SD)、总氮(TN)、总磷(TP)、氨氮(NH4+-N)、硝态氮(NO3--N)、亚硝态氮(NO2--N)、高锰酸盐指数、BOD5等水环境因子指标,对沙湖浮游植物密度、生物量、叶绿素a含量与水环境因子进行相关分析、多元逐步回归分析和典范对应分析.结果表明,沙湖浮游植物密度、生物量、叶绿素a含量与WT、TN、TP、高锰酸盐指数、BOD5之间显著正相关,与SD之间呈显著负相关.浮游植物密度、叶绿素a含量与WT、SD、TN、TP、高锰酸盐指数、BOD5之间有显著的线性回归关系,影响沙湖浮游植物密度的主要水环境因子依次为WT、高锰酸盐指数、SD、BOD5、TP、TN,影响沙湖叶绿素a含量的主要水环境因子依次为高锰酸盐指数、WT、SD、TP、TN、BOD5;浮游植物生物量与WT、SD、TN、TP、高锰酸盐指数之间有显著的线性回归关系,影响沙湖浮游植物生物量的主要水环境因子依次为WT、TP、高锰酸盐指数、SD、TN.浮游植物与水环境因子的CCA排序结果将16种浮游植物分为3组,呈现明显的季节分布特征,SD、高锰酸盐指数、WT、TN、TP是影响沙湖浮游植物群落动态分布的主要水环境因子.     

鄱阳湖浮游植物时空变化特征及影响因素分析

在5月、9月、11月对鄱阳湖浮游植物开展野外调查,分析鄱阳湖浮游植物的时空分布特征及原因.结果表明:在群落结构上,鄱阳湖浮游植物样品中共发现8门107属,其中绿藻门54属,占浮游植物总数的50%.3次调查平均生物量最高的为硅藻门(蓝藻门藻细胞密度最高),生物量为0.29 mg·L-1,占浮游植物总生物量的28%,是鄱阳湖的优势藻门;其次分别为隐藻门、甲藻门和绿藻门,分别占26%、21%和17%.空间分布上,南部湖区浮游植物生物量最高,中部区次之,北部湖口水道区最低;时间分布上,5月份浮游植物生物量最高,11月份最低.温度、悬浮物和透明度是影响藻类时空分布的主要影响因素.鄱阳湖总体水动力较好,水华暴发总体风险小,但中部和南部水动力弱的湖区,藻量高,仍有水华风险.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.     

Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Organochlorine pesticides in soils under different land usage in the Taihu Lake region, China

A field study was conducted in the Taihu Lake region, China in 2004 to reveal the organochlorine pesticide concentrations in soils after the ban of these substances in the year 1983. Thirteen organochlorine pesticides (OCPs) were analyzed in soils from paddy field, tree land and fallow land. Total organochlorine pesticide residues were higher in agricultural soils than in uncultivated fallow land soils. Among all the pesticides, ΣDDX (DDD, DDE and DDT) had the highest concentration for all the soil samples, ranging from 3.10 ng/g to 166.55 ng/g with a mean value of 57.04 ng/g and followed by ΣHCH, ranging from 0.73 ng/g to 60.97 ng/g with a mean value of 24.06 ng/g. Dieldrin, endrin, HCB and α-endosulfan were also found in soils with less than 15 ng/g. Ratios of p,p'-(DDD DDE)/DDT in soils under three land usages were: paddy field ＞ tree land ＞ fallow land, indicating that land usage inlfuenced the degradation of DDT in soils. Ratios of p,p'-(DDD DDE)/DDT ＞1, showing aged residues of DDTs in soils of the Taihu Lake region. The results were discussed with data from a former study that showed very low actual concentrations of HCH and DDT in soils in the Taihu Lake region, but according to the chemical half-lives and their concentrations in soils in 1980s, the concentration of DDT in soils seemed to be underestimated. In any case our data show that the ban on the use of HCH and DDT resulted in a tremendous reduction of these pesticide residues in soils, but there are still high amounts of pesticide residues in soils, which need more remediation processes.     

Sorption of 1-naphthol by plant cuticular fractions

The contribution of aliphatic-rich plant biopolymer to sorption of hydrophobic organic compounds is significantly important because of their preservation and accumulation in the soil environment,but sorption mechanism is still not fully understood.In this study, sorption of 1-naphthol by plant cuticular fractions was examined to better understand the contributions of respective fraction.Toward this end,cuticular materials were isolated from the fruits of tomato by chemical method.The tomato cuticle sheet consisted of waxes (6.5 wt%),cuticular monomer (69.5 wt%),and polysaccharide (24.0 wt%).Isotherms of l-naphthol to the cuticular fractions were nonlinear (N value (0.82-0.90)) at the whole tested concentration ranges.The KodKow ratios for bulk cuticle (TC1),dewaxed cuticle (TC2),cutin (TC4),and desugared cuticle (TC5) were larger than unity,suggested that tomato bulk cuticle and cutin are much powerful solption medium.Sorption capability of cutin (TC4) was 2.4 times higher than the nonsaponifiable fraction (TC3).The 1-naphthol interactions with tomato cuticular materials were governed by both hydrophobic-type interactions and polar (H-bonding) interactions. Removal of the wax and polysaccharide materials from the bulk tomato cuticle caused a significant increase in the sorption ability of the cuticular material.There was a linear negative trend between K_(oc) values and the amount of polysaccharides or fraction's polarities ((N O)/C);while a linear positive relationship between K_(oc) values and the content of cutin monomer (linear R~2=0.993) was observed for present in the cuticular fractions.Predominant sorbent of the hydrophobic organic compounds (HOCs) in the plant cuticular fraction was the cutin monomer,contributing to 91.7% of the total sorption of tomato bulk cuticle.