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Pseudocycnus appendiculatus Heller, 1868 (copepoda,dichelesthiidae) in New Zealand waters 总被引:1,自引:1,他引:0
G. C. Hewitt 《新西兰海洋与淡水研究杂志》2013,47(1):169-176
Pseudocycnus appendiculatus Heller is described and recorded, for the first time from New Zealand, on Thunnus alalunga (Bonnaterre, 1788). Pseudocycnus spinosus Pearse, 1951 and P. thynnus Brandes, 1955 are thought to be synonyms of P. appendiculatus. Other species previously placed in the genus are discussed and the action of Yamaguti (1963) in removing them to other genera supported. It is suggested that the family Pseudocycnidae Yamaguti, 1963 cannot be differentiated from the family Dichelesthiidae Bassett‐Smith, 1898. 相似文献
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Characterization of sediments in an abandoned mining area; a case study of Mansfeld region,Germany 总被引:1,自引:0,他引:1
Rainer?WennrichEmail author Jürgen?Mattusch Peter?Morgenstern Klaus?Freyer Hanns-Christian?Treutler Hans-Joachim?St?rk Lutz?Brüggemann Albrecht?Paschke Birgit?Daus Holger?Weiss 《Environmental Geology》2004,45(6):818-833
The distribution of selected heavy metals, including some radionuclides, metalloids and non-metals was determined in stream sediments in a region influenced by abandoned copper mining and ore processing activities. A considerable amount of the ore processing waste with a very complex composition and highly elevated concentrations of zinc, sulfur, lead, copper, arsenic, and a lot of other elements in the range between 100 and 1,000 mg/kg (Sb, Mn, Ni, Cr, Cd, Hg, and Ag) was piled up on mine dumps. The dispersion of the pollutants originating from this source and their environmental impact were investigated. Both, sediments and original waste material were studied to indicate the pathways and the mobilization behavior of different pollutants. For this purpose, the process of the elution of pollutants by application of different fractionation schemes was studied. The capabilities of different analytical techniques are shown for the analysis of solid samples (X-ray fluorescence spectrometry, Gamma-spectrometry) and liquid ones (ICP-atomic emission spectrometry, ICP-mass spectrometry and different techniques of atomic absorption). Additionally, the coupling of ion chromatography and ICP-MS detection was used to study the distribution of arsenic species in the sediment cores of a lake which acts as a natural sink for the region. 相似文献
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根据残余点生成机理,建立了残余点发生概率与干涉回波信号相关性内在联系的数学模型。据此,提出了以残余点的数目作为衡量干涉复图像整体配准质量的定量尺度。实验结果表明,该方法简便精确,尤其适用于系统基线较长时配准结果的比较、择优,从而能最大程度地减小数字高程模型中因配准精度欠佳所引起的误差。 相似文献
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煤燃烧过程中微量元素的迁移和富集 总被引:5,自引:0,他引:5
煤中微量元素在燃烧过程中产生迁移与富集。大部分元素在煤的燃烧产物中得以富集,一些挥发性强的元素将扩散到大气中。在飞灰中,大部分环境有害元素的富集程度与其粒度成反比,即在细粒飞灰中更加富集,由此对人体健康的潜在危害也更大。在我国,大型燃煤电厂的环境问题值得重视,同时大量的民用炉灶产生的环境污染更加严重,值得进一步研究与治理。 相似文献
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Soil and sand fine particles, which may be resuspended as fine dust in the atmosphere, contain a variety of anthropogenic
and natural organic components. Samples of fine soil and sand particles (sieved to <125 μM) were collected from the Riyadh
area in the summer of 2003 and extracted with a mixture of dichloromethane and methanol (3:1, v:v). The derivatized total
extracts were analyzed by gas chromatography–mass spectrometry in order to characterize the composition and sources of the
organic components. Both anthropogenic and natural biogenic inputs were the major sources of the organic compounds in these
extracts. Discarded plastics and vehicular emission products were the major anthropogenic sources in the fine particles from
populated areas of the city. Their tracers were plasticizers, UCM, n-alkanes, hopanes and traces of steranes. Vegetation was the major natural source of organic compounds in samples from outside
Riyadh and included n-alkanols, n-alkanoic acids, n-alkanes, methyl alkanoates, sterols and triterpenoids. Carbohydrates had high concentrations (42–54%) in all samples and
indicate sources from decomposition of cellulose and/or the presence of viable microbiota such as bacteria and fungi. The
results were also compared with the data obtained in winter 2002 and showed that anthropogenic inputs were higher in summer
than in winter, whereas the opposite trend was observed for natural inputs. 相似文献
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地下水中多种农药快速检测是全面表征地下水水质、确保地下水安全的重要技术支撑。本文结合现有检测标准和文献中农药需分类分别前处理和测试的问题,采用气相色谱-质谱仪,通过对水样前处理方法和气相色谱-质谱分析条件进行选择和优化,建立了地下水中91种农药气相色谱-质谱同时测定的快速分析方法。经优化,目标物采用脉冲不分流进样,Zebron Multiresidue-2色谱柱分离,分段选择离子扫描,内标法定量,多数农药在1.0~1000μg/L浓度范围内线性良好,相关系数在0.9901~0.9997之间。水样经二氯甲烷液液萃取浓缩后上机测试,各农药方法检出限为3.1~12.5ng/L,平均加标回收率在54.3%~129%之间,相对标准偏差(RSD)为1.2%~20%。本方法快速、简单,准确度高,不仅显著提高了地下水中多种类农药残留分析效率,降低了分析成本;而且方法更适合大批量地下水样品的快速筛查,从而保证了样品分析的时效性。该方法已成功应用于全国地下水污染调查专项。 相似文献
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保护性耕作改善东北农田黑土土壤生物多样性及其生态功能 总被引:2,自引:0,他引:2
保护性耕作是攻克黑土地保护和利用的核心技术之一。研究立足中国科学院黑土区农业生态重点试验室保护性耕作长期定位试验基地,系统梳理总结了农田黑土土壤生物多样性对保护性耕作的响应特征。与传统耕作相比,保护性耕作显著增加各生物类群(微生物、线虫、跳虫、螨类及蚯蚓)的物种丰富度(1%~8%)、数量(25%~57%)和生物量(30%~50%),提高食物网网状结构的复杂性及各营养级间的连通性(14%~32%),促进土壤生物在固土蓄水、土壤碳固存、氮素高效利用以及稳定作物产量四方面生态功能的可持续性发挥。研究结果表明,实施保护性耕作可有效利用土壤生物的功能潜力,实现东北黑土区农田生态系统的健康发展、服务国家粮食安全产业带建设和现代农业发展。 相似文献