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Heavy metal is a main pollutant in the marine ecosystem, so study on the effect of heavy metal on phytoplankton is important.
Algae (Chaetoceros sp.,Dunaliella sp.,Dicrateria zhanjiangenis Hu. var. sp.) were laboratory cultured to observe the effect of heavy metals on their growth. The effect of different metal ion concentration,
the detoxication effect of complexation agents and the growth of algae in different media and different nutrition levels were
studied to evaluate the effect of metal speciation. It is proved that trace amount of heavy metals can stimulate the growth
of algae cells but that high concentration is lethal. The sequence of toxicity is Cd2+>Zn2+>Pb2+. In ordinary nutrition conditions, the detoxication sequence of complexation agents toChaetoceros sp. is EDTA >sodium salicylate>sodium oxalate >sodium citrate>sulfanilic acid>O-phenanthroline. This is in good conformity
with the stability constant sequence of these agents with copper and good evidence that toxicity of metal ion is related to
its activity and not to its total concentration.
Project supported by the Fund of Excellent Young Teachers of State Educational Commission of China. 相似文献
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华南地区5月降水的水汽特征分析 总被引:1,自引:0,他引:1
利用国家气候中心的降水资料及NCEP/NCAR再分析资料、NOAA海温资料分析了华南地区5月降水的主要水汽通道及变异机制。发现异常多雨年的水汽主要来自南海、孟加拉湾和青藏高原南侧;异常少雨年则因西太平洋副热带高压(简称副高)偏东,来自南海的水汽缺失,只有来自孟加拉湾和高原南侧的两股水汽,因而南海的水汽是影响华南地区5月降水的重要因素。分析发现当北太平洋的准东西向海温异常是"负正负"分布时,南海地区为异常的反气旋性环流,有利于副高西伸加强;北太平洋海温距平为"正负正"异常分布时,南海地区为异常的气旋性环流,副高东退减弱。此外,北方南下冷空气的阻挡使得季风北界位置偏南,冷空气和季风在华南地区交汇导致5月降水异常增多。 相似文献
6.
紫花苜蓿种植对山地荒沟客土理化性质的影响 总被引:3,自引:0,他引:3
试验在客土回填后的山地荒沟,设置紫花苜蓿草地试验区,连续2 a研究紫花苜蓿种植对客土理化性质的影响,结果得出:自然条件下,春季播种紫花苜蓿,可以加速山区荒沟植被恢复,改善客土理化性质,播种后第2 a,地上生物量与覆盖度达到最高,分别为2 1.5 kg/hm2和74.1%,0~10 cm土层中pH值明显降低,土壤速效钾相对增加,全氮、碱解氮含量显著提高,达到0.657 g/kg与39.54 mg/kg;播种后第3 a,10~20 cm土层内土壤容重显著减小,达1.241 g/cm3,总孔隙度显著提高,5.0~17.5 cm土层土壤紧实度显著降低,同时,0~10 cm土层速效磷含量下降速度相对减缓,有机质含量显著升高,达到9.253 g/kg。 相似文献
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Variation in the sediment deposition behind check‐dams under different soil erosion conditions on the Loess Plateau,China
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Yanhong Wei Zhong He Juying Jiao Yujin Li Yixian Chen Hengkang Zhao 《地球表面变化过程与地形》2018,43(9):1899-1912
To maintain a reasonable sediment regulation system in the middle reaches of the Yellow River, it is critical to determine the variation in sediment deposition behind check‐dams for different soil erosion conditions. Sediment samples were collected by using a drilling machine in the Fangta watershed of the loess hilly–gully region and the Manhonggou watershed of the weathered sandstone hilly–gully (pisha) region. On the basis of the check‐dam capacity curves, the soil bulk densities and the couplet thickness in these two small watersheds, the sediment yields were deduced at the watershed scale. The annual average sediment deposition rate in the Manhonggou watershed (702.0 mm/(km2·a)) from 1976 to 2009 was much higher than that in the Fangta watershed (171.6 mm/(km2·a)) from 1975 to 2013. The soil particle size distributions in these two small watersheds were generally centred on the silt and sand fractions, which were 42.4% and 50.7% in the Fangta watershed and 60.6% and 32.9% in the Manhonggou watershed, respectively. The annual sediment deposition yield exhibited a decreasing trend; the transition years were 1991 in the Fangta watershed and 1996 in the Manhonggou watershed (P < 0.05). In contrast, the annual average sediment deposition yield was much higher in the Manhonggou watershed (14011.1 t/(km2·a)) than in the Fangta watershed (3149.6 t/(km2·a)). In addition, the rainfalls that induced sediment deposition at the check‐dams were greater than 30 mm in the Fangta watershed and 20 mm in the Manhonggou watershed. The rainfall was not the main reason for the difference in the sediment yield between the two small watersheds. The conversion of farmland to forestland or grassland was the main reason for the decrease in the soil erosion in the Fangta watershed, while the weathered sandstone and bare land were the main factors driving the high sediment yield in the Manhonggou watershed. Knowledge of the sediment deposition process of check‐dams and the variation in the catchment sediment yield under different soil erosion conditions can serve as a basis for the implementation of improved soil erosion and sediment control strategies, particularly in semi‐arid hilly–gully regions. Copyright © 2018 John Wiley & Sons, Ltd. 相似文献
8.
Heavy metal is a main pollutant in the marine ecosystem . so study on the effect of heavy metal on phytoplankton is important . Algae (Chaetoceros sp . , Dunaliella sp . ., Dicrateria zhanjiangenis Hu . var . sp .) were laboratory cultured to observe the effect of heavy metals on their growth . The effect of different metal ion concentration , the detoxication effect of complexation agents and the growth of algae in different media and different nutrition levels were studied to evaluate the effect of metal speciation . It is proved that trace amount of heavy metals can stimulate the growth of algae cells but that high concentration is lethal . The sequence of toxicity is Cd2+>Zn2+>Pb2+ . In ordinary nutrition conditions , the detoxication sequence of complexation agents to Chaetoceros sp . is EDTA > sodium salicylate > sodium oxalate > sodium citrate > sulfanilic acid > O-phenanthroline . This is in good conformity with the stability constant sequence of these agents with copper and good evidence that t 相似文献
9.
2020年7月26日鄂西南出现了一次极端暴雨过程,建始县城区及附近乡镇在10 h内雨量超过250 mm,导致罕见山洪灾害。利用常规资料,结合地面加密自动站、多普勒天气雷达以及高分辨率EC再分析资料,分析该过程天气形势背景、中尺度环境,以及暴雨中尺度对流系统发生发展过程及其机理,揭示极端暴雨成因。结果表明:(1)中高纬度维持两槽一脊,低纬度副热带高压稳定且位置适中,是鄂西南强降水较长时间维持的有利条件;(2)冷空气侵入四川盆地导致西南涡发展,涡前西南暖湿气流加强,加上鄂西南地形辐合抬升作用,形成深厚正涡度柱和强烈垂直上升运动,是导致极端暴雨产生的重要原因;(3)建始县附近先后经历了后向传播型(BB-QS)及涡旋型(VS)两个中尺度对流系统的影响,而“倒喇叭口”地形导致雷暴冷池逆流并与环境风形成稳定的中尺度辐合上升运动,是极端暴雨中尺度对流系统形成的关键因素。 相似文献
10.
Induction of EROD activity in Paralichthys olivaceus by polychlorinated biphenyl CB-28 总被引:2,自引:0,他引:2
Abstract-The test organisms (Paralichthys olivaceus) were exposed to CB-28 with differentspiked concentrations. After 72 h, EROD activities in livers of the test organisms were measured. It wasfound that EROD activities significantly mounted up with the increase of spiked quantity. Therefore,there existed a dose-response relationship between EROD activities and specific pollutant concentrations.In the meantime, the optimal conditions for the analysis of EROD activity were discussed. The limita-tion of EROD activities as a monitoring parameter was also analyzed. 相似文献