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81.
Iron and phosphorus limitation and their combined effects on the growth and development of Prorocentrum micans Ehrenberg (Dinophyceae) and Cryptomonas sp. (Cryptophyceae) have been studied. The growth status of these algae at different Fe and P levels is quantitatively analyzed through lab-culture experiments. Results show that Fe starvation can misalign chloroplast lamellas, and metamorphose and twist thylakoid, leading to a retarded growth rate. The combined effects of Fe and P can accelerate their growth, and an optimum culture condition to maintain the maximum growth rate is a combination of 0.05 μM Fe and 50 μM P. Algal uptake of Fe and P are synergistic. Their cellular concentrations bear significant correlations (r = 0.9979 for Cryptomonas sp. and 0.9938 for P. micans; P < 0.01) and correspondingly the molar P:Fe ratios are ∼160:1 and ∼356:1, respectively. These findings will provide novel insights for revealing the crucial factors controlling the occurrence of algal blooms.  相似文献   
82.
To investigate the relative importance of mesoscale physical events, such as upwellings and physical and chemical variables during an algae bloom of Prorocentrum minimum, 25 sampling sites were established offshore of the Navachiste Lagoon Complex on the east side of the Gulf of California. Samples were analyzed for phytoplankton concentration, water chemistry, and temperature during November 1999, January, March, April, May, and August 2000. Satellite imagery of sea surface temperature (SST) for April 2000 was processed to obtain a synoptic view of the area during the extraordinary bloom of P. minimum in the open waters of the Gulf of California. The bloom was associated with change of oceanographic conditions from moderate winds to calm period, temperature increase and high nitrate (NO3-N) and ammonia (NH4+-N) content in the offshore waters. Depletion of these nutrients during the bloom suggests that this species uses both types of nitrogen substrates. Cysts in the northernmost sampling stations in January and March indicate that upwelling water, rich in nitrates, also carried a seed stock population of P. minimum. SST patterns in the satellite imagery suggest wind-forcing as the responsible mechanisms triggering the algal bloom offshore of the Navachiste Lagoon Complex.  相似文献   
83.
Prorocentrum lima (Ehrenberg) Dodge has been found for the first time during the summer of 2007 inside Ortona harbor and along the coast of the Abruzzo region, a slightly eutrophic area influenced by runoff from a nearby river. The investigations were conducted in two harbors and at six coastal sampling stations. Samplings were conducted using a phytoplankton net and with a pump. Average P. lima cellular concentrations were 3.2 × 104 cells L−1. Other well-known toxic and potentially toxic phytoplankton species have been considered. The number of toxic cells from net samples were higher than the numbers of toxic cell samples collected without the net. Occurrences of P. lima with abiotic factors revealed that temperature was positively correlated with P. lima abundance (p = 0.01), while salinity was highly negatively correlated with P. lima presence (p = 0.001). The total phytoplankton community was studied.  相似文献   
84.
There is an increasing understanding and requirement to take into account the effects of invasive alien species (IAS) in environmental quality assessments. While IAS are listed amongst the most important factors threatening marine biodiversity, information on their impacts remains unquantified, especially for phytoplankton species. This study attempts to assess the impacts of invasive alien phytoplankton in the Baltic Sea during 1980-2008. A bioinvasion impact assessment method (BPL - biopollution level index) was applied to phytoplankton monitoring data collected from eleven sub-regions of the Baltic Sea. BPL takes into account abundance and distribution range of an alien species and the magnitude of the impact on native communities, habitats and ecosystem functioning. Of the 12 alien/cryptogenic phytoplankton species recorded in the Baltic Sea only one (the dinoflagellate Prorocentrum minimum) was categorized as an IAS, causing a recognizable environmental effect.  相似文献   
85.
利用光学显微镜、分子生物学方法,对分离自广西北部湾海域的三角棘原甲藻Prorocentrum triestinum BBW-02藻株的形态特征进行了描述,并探讨了其分子系统进化关系。三角棘原甲藻BBW-02细胞呈长卵形或披针形,细胞长20~26μm,宽10~14μm,顶刺形如矛尖,刺丝胞孔数量较少,排列不规则,主要分布于壳板边缘,距离细胞底端1/3处壳板两侧各有2个近于对称排列的刺丝胞孔。18S rDNA序列同源检索和系统进化分析表明,三角棘原甲藻BBW-02与其他地理株系的三角棘原甲藻聚为一支,亲缘关系密切,遗传差异仅为0.000~0.001。与其他种类相比,三角棘原甲藻BBW-02与同属中的P.gracile亲缘关系最近。  相似文献   
86.
FITC‐conjugated lectins proved to be effective probes for differentiating between morphologically similar dinoflagellate species isolated from New Zealand coastal waters. In particular the binding (fluorescence) of peanut (PNA) lectin differentiated G. mikimotoi from Gymnodinium sp. (Waimangu) and G. pulchellum and the non‐binding of Helix pomatia (HPA) and wheat germ (WGA) lectins discriminated between G. mikimotoi and the other Gymnodinium species tested. G. breve (Florida) was differentiated from the New Zealand isolates by binding with soy bean (SBA) lectin. Ulex europeus (UEA) distinguished the toxic species Alexandrium minutum from the morphologically similar, but non‐toxic, Cachonina hallii. Two strains of Prorocentrum lima (Spain and Rangaunu) were not differentiated by the lectins, but P. lima was differentiated from P. compressum.  相似文献   
87.
Harmful algal blooms recently have been under the spotlight throughout the world, because of their negative impact on the marine environment, aquaculture, fisheries as well as public health. The development of methods for rapid and precise identification and quantification of causative species is essential for the warning and monitoring of blooms, among which the techniques based on taxonomic probes are the most favored. In this study, two harmful algae, i.e., Prorocentrum minimum and Karenia mikimotoi were taken into consideration. The partial large subunit rDNA (D1-D2) of both species were firstly PCR-amplified, cloned and sequenced. The obtained sequences were then introduced to carry out alignment analysis for gene specific regions. Three respective candidate probes for each species were designed and used to screen the optimal probe by performing fluorescence in situ hybridization (FISH) tests. The results showed that the probes Pmin0443 and Kmik0602 displayed the best hybridization for P. minimum and K. mikimotoi, respectively. Both the specific (taxonomic) (Pmin0443 and Kmik0602) and the control probes (UniC0512 and UniR0499) were used for cross-reactivity tests with other microalgae in our laboratory. The probes Pmin0443 and Kmik0602 are specific and could be served as taxonomic probes introduced into the techniques targeting rRNA, such as FISH, sandwich hybridization, and DNA-microarray assay of P. minimum and K. mikimotoi in the future. Finally, FISH analyses with both probes were performed on the simulated field samples. The probes could hybridize exclusively with the target cells well, and no significant difference (p >0.05) was observed in the cell densities of the samples determined by FISH and light microscopy (LM). All suggest that the probes are specific and could be introduced into FISH for the monitoring of both harmful algae.  相似文献   
88.
五种/株原甲藻核糖体小亚基(18S rRNA)基因克隆及序列分析   总被引:8,自引:0,他引:8  
采用分子克隆及序列比对的方法,对五种/株赤潮原甲藻18SrRNA基因全长序列进行扩增、克隆和序列测定,并从GenBank上下载13个原甲藻18SrRNA基因接近全长的序列,用NJ法和ME法构建了原甲藻属的系统树。结果表明,五种/株原甲藻18SrRNA基因扩增序列长度为1782—1783bp,其中来自南海(中国海域)和来自美国海域的两株微小原甲藻(Prorocentrumminimum)的序列完全一致;东海的赤潮原甲藻(Prorocentrumsp·)与具齿原甲藻(P·dentatum)的序列也完全一致,与微小原甲藻只有5个碱基的差异;而海洋原甲藻(P·micans)与微小原甲藻和具齿原甲藻的序列差异较大,分别为27个和28个碱基。通过NJ法和ME法构建的系统树基本一致。由系统树可以看到:原甲藻属大致分为两支,本实验的微藻全部分布在同一支上。18SrRNA基因序列还将有助于有害赤潮藻快速鉴定的特异性分子探针的研制。  相似文献   
89.
利用测定净光合放氧速率的方法研究了温度、盐度、pH值和光照强度对东海原甲藻(Prorocentrum donghaiense)光合作用的影响.东海原甲藻适宜的温度范围是15~30℃,最适温度22~28℃,低于9℃和高于33℃,不能进行光合作用;适宜的盐度范围为22~35,最适盐度28~30;适宜的pH范围较小,为6.0~9.0, 最适pH值范围7.5~8.5,与所生活的海洋环境一致,pH高于9.5,不能进行有效的光合作用,pH10.0可致死全部细胞;光饱和点在600 μmol/(m~2·s)附近,在更高光强下没有发生光抑制.测定的对光合作用适宜的条件和最适条件与他人培养试验结果一致,与东海原甲藻赤潮发生现场的生态调查结果吻合.表明通过测定光合作用速率对主要生态因子变化的响应,可以掌握藻类生长繁殖对主要生态因子的要求以及对这些因子变化的适应能力.了解赤潮藻的生理生态特性是认识赤潮发生机理的基础,本研究结果为认识赤潮发生的机理提供了重要的信息.  相似文献   
90.
采用单养和混养的方法,在实验条件下研究了东海原甲藻对中华哲水蚤摄食和消化酶活性的影响.结果表明:(1)中华哲水蚤对东海原甲藻存在一定摄食行为,藻类密度对摄食率有明显的影响.实验密度下,中华哲水蚤对东海原甲藻的最大摄食率为930cells/(ind·h).滤水率随着藻密度的增加而呈单一性的下降;(2)混养条件下,中华哲水蚤对金藻和东海原甲藻的摄食率均较单养时下降,滤水率的变化与摄食率相似;(3)不同藻密度下,昆布多糖酶活性都明显高于麦芽糖酶和纤维二糖酶的活性,而麦芽糖酶活性又稍高于纤维二糖酶的活性.与金藻相比,东海原甲藻实验组中华哲水蚤3种消化酶活性明显升高(P<0.05).  相似文献   
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