共查询到20条相似文献，搜索用时 46 毫秒
1.
有毒铜绿微囊藻对鱼和溞的毒性 总被引：7，自引：0，他引：7
用有毒铜绿微囊藻细胞及其从毒细胞中提取的毒素喂养和腹腔注射鱼类,结果表明:(1)微囊藻毒素MCYST-LR对所有实验过的鱼有毒害作用(LD50为110-500μg/kg).注射毒素24h后,鱼肝电镜超微结构观察均表现出肝损伤.(2)在受控条件下,当用有毒铜绿微囊藻作为食物喂养日鲢和罗非鱼时,鱼类能在以毒藻为唯一食物的环境中生活20d以上.白鲢和罗非鱼粪便的毒性比喂食藻类的毒性分别降低约2-4.5倍,其肝的超微结构现察仍有轻度损伤.(3)在培养液中加入15μg/mLMCYST-LR和用实验室纯培养的铜绿微囊藻作为食物培养枝角类时,均可使它们在48h死亡.以无毒微囊藻培养时则生长不良亦不怀卵,表明它不是枝角类合适的食物. 相似文献
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黑藻(Hydrilla verticillata)对铜绿微囊藻(Microcystis aeruginosa)抑制作用 总被引：17，自引：0，他引：17
采用黑藻(Hydrilla verticillata)和铜绿微囊藻(Microcystis aeruginosa)共同培养的实验方法，追踪测定微囊藻的生长量、光合速率等相关生理生化指标以及观察藻细胞超微结构变化，研究黑藻对铜绿微囊藻的抑制作用及其机制．结果表明，黑藻对铜绿微囊藻的生长有明显的抑制作用，表现为藻细胞生长量显著降低，细胞超微结构进行性损伤直至细胞解体，藻体叶绿素a含量和光合速率急剧下降，呼吸速率、超氧物歧化酶(SOD)活性均呈现先升高后下降的趋势，膜脂过氧化产物丙二醛(MDA)的积累量与膜的损伤程度相一致．在黑藻养殖水中初步分离得到黑藻分泌的抑藻物质． 相似文献
3.
河蟹养殖池塘微囊藻水华毒性及其光合作用活性特征 总被引：1，自引：0，他引：1
苏州市吴中区一河蟹养殖池塘在2013年7月和8月发生了严重的微囊藻水华.采用单一和双重PCR扩增微囊藻毒素合成酶基因,用以检测微囊藻水华是否产毒,结果显示为阳性.同时,采用高效液相色谱测定微囊藻水华的毒性大小.结果表明:7月和8月微囊藻水华的胞内微囊藻毒素浓度分别为1.49和0.88μg/L,胞外微囊藻毒素的浓度分别为0.75和1.09μg/L.另外,采用浮游植物荧光仪Phyto-PAM测定河蟹养殖水体形成水华的微囊藻的光合作用活性.结果显示:7月和8月水华微囊藻的最大光量子产量Fv/Fm分别为0.48和0.44,实际光量子产量ΦPSII分别为0.38和0.32,表明形成水华的微囊藻有较高的生长潜力.非光化学荧光淬灭值NPQ分别为0.28和0.36.从快速光响应曲线RLC的特征参数来看,7月水华微囊藻的光合作用活性和光能利用效率高于8月.本研究结果表明,河蟹养殖池塘水体受到微囊藻水华和微囊藻毒素的污染,进而可能对河蟹食品安全构成潜在威胁. 相似文献
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铜绿微囊藻(Microcystis aeruginosa)与三种丝状蓝藻间的相互作用 总被引：10，自引：0，他引：10
研究了单细胞铜绿微囊藻和三种丝状蓝藻（水华束丝藻、水华鱼腥藻及土生席藻）间的相互作用，包括以下两个方面的内容：①铜绿微囊藻细胞滤出液对水华束丝藻、水华鱼腥藻及土生席藻生长的影响；②水华束丝藻、水华鱼腥藻及土生席藻细胞滤出液对铜绿微囊藻生长的影响．研究发现，当滤出液浓度为60％（滤出液与BG11的体积比为3：2）时，铜绿微囊藻细胞滤出液对水华束丝藻、水华鱼腥藻的生长有显著促进效果，尤其对水华束丝藻的作用更加明显；对土生席藻的生长却起着微弱的抑制作用，仅表现于100％细胞滤出液中．对铜绿微囊藻而言，土生席藻细胞滤出液对其的生长起着显著抑制作用，浓度越高、抑制作用越强；而水华束丝藻、水华鱼腥藻仅在100％细胞滤出液中才表现出微弱的抑制作用．为验证营养盐浓度差异是否影响滤出液的作用效果，进行了无机营养盐（NO3-N、NH4^＋-N、PO4-P）干扰的消除试验．结果表明，无机营养盐（（NO3-N、NH4^＋-N、PO4-P）的改变并不影响滤出液的作用效果，从而我们推测水华蓝藻之间存在着化感作用．本研究为解释自然水体中藻类种群演替的原因，深入认识水华蓝藻的动力学机制提供了新的实验证据． 相似文献
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微囊藻毒素粗提物对水环境中温和气单胞菌活的非可培养状态的影响 总被引：2，自引：0，他引：2
细菌VBNC状态(Viable but non-culturable state),又称"活的非可培养状态",是自然水体中广泛存在的细菌的一种特殊存活状态,复杂的环境因子变化是VBNC状态转换的可能原因.本研究利用接种温和气单胞菌的无菌湖水,研究铜绿微囊藻(Microcystis aeruginosa)培养液和微囊藻毒素粗提液对水环境中温和气单胞菌VBNC状态转换的影响,结果发现,温和气单胞菌在无菌湖水中同时存在VBNC状态和可培养状态;产毒微囊藻培养液和微囊藻毒素粗提液均能促进温和气单胞菌中VBNC细菌与可培养细菌之间的状态转换,说明微囊藻毒素可能是水环境中影响细菌VBNC状态转换的重要环境因素,其进一步的分子机制研究正在进行中. 相似文献
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有害蓝藻释放微囊藻毒素（MCs），严重威胁饮用水源地用水安全.为了解巢湖MCs污染状况及其异构体组成对水质的影响，于2012年夏季（8月）和秋季（11月），2013年冬季（2月）和春季（5月）进行采样分析，研究了巢湖水体中胞内微囊藻毒素（IMCs）和胞外微囊藻毒素（EMCs）异构体的时空分布及其与环境因子的关系.结果发现，IMCs和EMCs的平均浓度变化范围分别为0.12~6.45 μg/L和0.69~1.92 μg/L.在3种常见的异构体中，MC-RR和MC-LR比例较高，MC-YR最低，MC-RR和MC-LR是巢湖水体中MCs的主要异构体类型.IMCs和EMCs的异构体浓度及其比例呈现不同的时空分布特征.微囊藻生物量、水温、总磷浓度是影响IMCs和EMCs异构体浓度及其组成变化的关键环境因子.本研究表明巢湖富营养化严重的西湖区夏季能合成更多的MC-RR异构体，而秋、冬季节偏向于释放生理毒性更强的MC-LR异构体.了解MCs异构体组成变化及其关键影响因素，有助于预测预警水体MCs污染状况和评估饮用水源地MCs风险. 相似文献
7.
太湖铜绿微囊藻磷摄取动力学若干重要参数与其竞争优势相关研究 总被引：15，自引：0，他引：15
对从太湖分离的铜绿微囊藻(Microcystisaerugionosa)进行了不同氮磷比对生长影响的实验,以探索蓝藻生长优势形成的基础.实验结果虽然在一定程度上符合“氮磷摩尔比低于29蓝藻将会占据优势”的理论,但发现只在较低的营养水平时比较吻合.同时进行了不同磷营养条件下磷营养摄取与生长的实验,为太湖富营养化研究中应用的水质模型提供所需的参数值.微囊藻生长的磷半饱和常数Ks=16.21μM、磷摄取的半饱和常数Km=17.66μM、藻细胞最小的磷份额K=4.36μg/mg(dw);微囊藻在实验条件下的过度储磷系数Q0/Qmax=0.14;测定了磷饥饿和磷丰富时细胞最大的摄磷速率分别为1.66μg/(L·mg·h)和0.06μg/(L·mg·h).可见初始细胞内磷份额较低的藻细胞对磷的吸收速率要比胞内磷份额较高的藻细胞高. 相似文献
8.
浮游植物间的交互化感作用被认为是自然水体中浮游生物群落演替及优势种转换的主要因素之一.铜绿微囊藻(Microcystis aeruginosa)是富营养化湖泊中的常见蓝藻,其产毒品系相较非产毒品系具有较高的竞争优势,其产生的主要次生代谢产物微囊藻毒素-LR(MC-LR)通常被认为是重要的化感物质.但是到目前为止其在水生生态系中的生物学功能尚不明确.为探究并区分MC-LR及其他次生代谢产物对浮游植物的化感效应,本文研究了MC-LR与高浓度普通小球藻(Chlorella vulgaris)生长及有效量子产率的剂量—效应关系;比较了能够产生显著抑制效应的MC-LR、能够产生同等浓度MC-LR的产毒品系铜绿微囊藻滤液以及细胞粗提液对小球藻生长及有效量子产率的抑制效应.结果显示,MC-LR能够对小球藻生长及有效量子产率产生抑制作用,并且抑制率随着MC-LR浓度的增加而增大.在用200μg/L及以上浓度的MC-LR感染24 h后,叶绿素a浓度为1500μg/L的小球藻的生长与有效量子产率均比对照组显著降低.能够产生相同浓度MC-LR的产毒品系铜绿微囊藻细胞滤液对其没有产生显著影响,而其细胞粗提液却能够产生更强的抑制效应.与MCLR处理组相比,粗提液处理组小球藻的生长及有效量子产率分别降低了14%和3%.以上结果表明,MC-LR对普通小球藻的化感作用具有剂量依赖性;MC-LR之外的其他次生代谢物也能够产生抑制效应. 相似文献
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五株微囊藻毒素降解菌的分离与鉴定 总被引：9，自引：0，他引：9
有毒蓝藻产生的蓝藻毒素导致地表水的污染已是全球普遍的现象,最常见的毒素是能导致肝癌的肝毒素微囊藻毒素(MC),迄今为止尚无适用的MC驱除技术,微生物降解MC可能是一条有效的途径．本研究以铜绿微囊藻(Microcystis aeruginosa PCC 7806)所产生的MC为底物,从多个形成微囊藻水华的水体中分离获得能显著降解MC的细菌18株,相对降解能力从18．4％到48．2％．对其中5株MC相对降解能力较强的菌,通过形态特征和生理生化特征分析,鉴定出5株菌分别为:不动细菌属(Acinetobacter)、肠杆菌属(Enterobacter)、微杆菌属(Microbacterium)、芽孢杆菌属(Bacillus)和弗拉特氏菌属(Frateuria),均不同于已报道的属种． 相似文献
10.
甲醛溶液对发头裸腹溞及其体表聚缩虫影响的试验 总被引：1，自引：0，他引：1
不同浓度的甲醛溶液对枝角类发头裸腹溞Moinairrasa的致毒效应以及对其体表附着的聚缩虫Zoothamniumsp．的杀灭效果的试验结果表明，12h、24h两个作用时段中，甲醛浓度与发头探腹溞相对存活率之间以及甲醇浓度与发头裸腹溞表聚缩虫营养体脱落率之间存在一定的函数关系．在确立上述函数基础上，可得出控制聚缩虫感染的两种有效方法：①在保证溞存活率不低于66％的情况下，选用最低有效浓度（19．mg／kg）的甲醛溶液作用24h可杀灭100％聚缩虫；②在保持溞存活率较高（70％－90％）的情况下，选用相应浓度的甲醛液作用24h杀灭87％－29％聚缩虫，并辅以更换新水等措施，也可将聚缩虫感染的危害控制在一定的范围内． 相似文献
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《国际泥沙研究》2014,(4)
正Director:Shangfu Kuang,China Vice-directors:Chunhong Hu,China Duihu Ning,China Guangquan Liu,China The International Research and Training Center on Erosion and Sedimentation(IRTCES)was jointly set up by the Government of China and UNESCO on July 21,1984.It aims at the promotion of international exchange of knowledge and cooperation in the studies of erosion and 相似文献
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《中国科学:地球科学(英文版)》2014,(3)
正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in both basic and applied research. 相似文献
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Richard D. Hey 《地球表面变化过程与地形》1979,4(1):59-72
Feedback mechanisms, which operate upstream through drawdown and backwater effects and downstream through sediment discharge are responsible for channel evolution. By combining these mechanisms with channel processes it euables a dynamic process-response model to be developed to simulate the initial evolution of straight gravel-bed channels. When erosion commences on a land surface, sediment entrained in the headwater reach by hydraulic action is selectively transported, deposited and reworked. This produces a damped oscillation between degradation and aggradation as the channel and valley respond to spatial and temporal variations in sediment calibre and hydraulic conditions. The initial cut and fill phases are responsible for valley incision and floodplain development while secondary and subsequent activity can produce river terraces. Eventually sediment entrainment in the headwaters declines as slopes are reduced. Subsequent channel evolution is relatively insignificant because it is dependent on local weathering activity producing material that can be transported on declining slopes. Therefore landforms produced during the initial phase of development, when local weathering was non-limiting, dominate the landscape. 相似文献
18.
Based on relocating the Jiujiang-Ruichang earthquake sequence which occurred on November 26, 2005 in Jiangxi Province with the double-difference （DD） algorithm and master event technique, the paper discusses the focal mechanism of the main shock （MsS.7） and the probable seismo-tectonics. The precise relocation results indicate that the average horizontal error is 0.31kin in a EW direction and 0.40kin in a NS direction, and the average depth error is 0.48kin. The focal depths vary from 8kin to 14kin, with the predominant distribution at 10kin - 12kin. The epicenter of the main shock is relocated to be 29.69^oN, 115.74^oE and the focal depth is about 10.Skin. Combining the predominant distribution of the earthquake sequence, the focal mechanism of the main shock and the tectonic conditions of N-E- and NW-strike faults growth in the seismic region, we infer that the main shock of the earthquake sequence was caused by a NW striking buried fault in the Rnichang basin. The nature of seismic faults needs to be further explored. 相似文献
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《水文科学杂志》2013,58(6)
Abstract The western reservoirs represent the principal groundwater system in Morocco. Demographic, industrial and agricultural developments during the last decade have markedly altered groundwater quality. The Mamora coastal aquifer system is among the Atlantic systems which are most heavily threatened by pollution. Agricultural and industrial activities, and rapid urban growth contribute to the pollution of the groundwater. Contamination transport is facilitated by a high permeability of the aquifer formations. In order to assess the actual groundwater quality of the Mamora aquifer and to understand the influence of the factors generating the pollution, an extensive multidisciplinary research programme is in progress, with hydrochemistry and microbiology playing essential roles. The present paper concerns the spatial distribution of physico-chemical parameters in the groundwater, subjected to domestic, industrial and agricultural pollution. Fifty-seven samples were analysed for several parameters (Ca2+, Mg2+, Na+, K+, Cl?, SO4 2?, HCO3 ?, NO3 ?, pH, electrical conductivity and temperature). The microbiological analysis of 143 samples reveals the presence of four kinds of indicator bacteria in the groundwater resources: faecal Streptococci, faecal coliform, Escherichia coli and Clostridium. The physico-chemical results and bacteriological monitoring show that the nitrate and bacteria concentrations exceed the maximum admissible levels, notably around pumping stations in the sectors of Sidi Taibi, Sidi Ahmed Taleb and Aïn Sbaâ. Contamination is generated by uncontrolled anthropogenic activities and accentuated by the high intrinsic vulnerability of the aquifer system. Several parameters appeared to exceed admissibility standards. Measures are recommended to prevent groundwater pollution in the region. 相似文献
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K.-G. Malle 《洁净——土壤、空气、水》1992,20(4):196-204
Zinc in the Environment. In 1990 the world production of zinc ammounted to 7 Mio. metric tons. The main areas of application were: galvanization, alloys like brass and zinc metal. The content in the earth crust varies between 10–300 ppm zinc with a mean of 70 ppm. Uncontaminated surface waters contain less than 10 mg/m3 zinc. Apart from civilization air contains 1–10 ng zinc per m3. These background concentrations are exceeded by orders of magnitude in zinc deposit areas and where anthropogenic influences predominate. Accumulation can occur in sediments and sewage sludge. Molluscs and Algae also accumulate zinc. Zinc is essential for live. With normal food the zinc supply of man is just sufficient. Bioaccumulation of zinc towards man or chronic oversupply of man is not known. Zinc has no teratogenic or mutagenic effects, a suspicion on a carcinogenic effect proved wrong. In stockbreeding and plant cultivation a minimum supply of zinc is necessary. Plants are relatively less sensitive against higher soil contents of zinc. Considering the toxicological and ecotoxicological effects of zinc in the environment, the critical organismens are marine invertebratae like tubifex, daphnia, gammarus and algae. But normally only a minor part of the total zinc contest is biologically available, depending on salt content and pH of the waters. 相似文献