外来树种在天津滨海地区的引进及在园林中的应用

综述了天津滨海地区引进外来树种的背景及背景和可行性,总结了外来树种在园林中的应用情况。指出外来树种丰富了该地区物种,增加了景观色彩,提高了生态安全。讨论了滨海地区近期外来树种的引进、应用等问题。     

Organic geochemical parameters for estimation of petrogenic inputs in the coastal area of Kavala City,Greece

Background, aims, and scope  Sediments and soils in coastal areas are frequently polluted by anthropogenic contaminants as the result of both riverine or terrestrial discharge and autochthonic marine emissions. In order to determine petrogenic contamination in the coastal industrial area of Kavala City in northern Greece, a combination of polycyclic aromatic hydrocarbon (PAH) and organic geochemical petroleum biomarker analyses has been performed on marine and freshwater sediments as well as soils. Materials and methods  Soils, freshwater, and marine sediments have been treated by standard extraction methods. The dried and desulphurized sample extracts have been fractionated by column chromatography, followed by addition of surrogate standards. Qualitative and quantitative data were obtained by gas chromatograph connected with a flame ionization and electron capture detector (GC-FID/ECD) and by GC linked to a mass spectrometer (GC/MS), whereas identification of compounds was based on EI⁺-mass spectra and gas chromatographic retention times. Quantitative data were obtained by integration of specific ion chromatograms. Results  The total PAH concentrations measured in the area varied highly, showing different levels from 18 up to 318,000 ng g⁻¹ dry weight (dw). Several PAH ratios, as well as the ratio of pristane (Pr) to phytane (Phyt), have been considered. Out of 39 samples, 22 revealed a specific distribution of hopane fingerprints indicating petrogenic input. Finally, in numerous samples, the ratio of 17α(H)-22,29,30-trisnorhopane (Tm) and 18α(H)-22,29,30-trisnorhopane (Ts) was calculated, as well as the ratio of 22S-17α(H),21β(H)-30 homohopane (αβC₃₁-hopane 22S) and 22R-17α(H),21β(H)-30 homohopane (αβC₃₁-hopane 22R). Discussion  Based on the specific PAH ratios, a group of samples was clearly characterized to be contaminated dominantly by combustion-derived emissions, whereas a second group of samples exhibited mixed influence from petrogenic and pyrogenic PAHs. On the other hand, the exhibition of specific hopane fingerprints in many samples indicates a direct petrogenic input. Finally, the values of the ratio of Tm/(Ts + Tm) and of αβC₃₁-hopanes 22S/(22S+22R)-isomer demonstrated an input of highly mature organic matter that has to be clearly attributed to petroleum-derived contamination, while the ratio of Pr/Phyt showed that most samples exhibited an input of organic matter. Conclusions  The coastal area of Kavala is strongly affected by anthropogenic contaminants. Petrogenic emissions were pointed out firstly by PAH analyses that separated dominantly pyrogenic contaminated sites from areas affected by both pyrogenic and petrogenic emissions. However, analyses of organic geochemical biomarkers revealed a much higher sensitivity in identifying petroleum-derived contaminations and were successfully used to differentiate several petrogenic contaminations in the marine and terrestrial samples. Recommendations and perspectives  Based on this study, it was recommended to use a complementary approach of source-specific substances to successfully characterize petrogenic emissions. Generally, a PAH-based source identification of petrogenic versus pyrogenic contaminations should be combined with petroleum biomarker analysis. PAH and biomarker ratios as well as individual biomarker fingerprints revealed a more comprehensive view on the quality and quantity of petrogenic emissions in sediments and soils.     

围垦对杭州湾南岸滨海湿地土壤养分分布的影响

在杭州湾南岸典型滨海湿地以空间代时间的方法,采集不同围垦年代的自然湿地土壤和围垦后利用土壤,研究了湿地土壤有机质、N和P的空间分布规律及围垦利用对养分空间分布的影响。结果表明,随围垦时间的增加,土壤表层全P含量表现为增加的趋势,围垦5年、25年和50年土壤全P含量比未围垦光滩分别增加12%、25%和76%;土壤有机质则表现为先降低后增加趋势,围垦5年和围垦25年土壤有机质相比未围垦光滩分别减少14%和50%,围垦50年则比未围垦光滩增加87%;土壤全N的分布趋势和有机质基本一致。对养分剖面分布的分析表明,围垦及其利用等人为干扰活动对养分的影响主要集中于土壤表层。相关性分析显示,土壤中全N含量与有机质含量呈现出显著的正相关,说明在土壤中N主要是以有机N的形态存在,而全P含量与有机质含量的关系不显著。土壤颗粒组成与土壤中有机质、N素等养分含量有较为明显的关系,有机质、全N与物理性黏粒(<0.01mm)的各组分都表现为显著或极显著正相关;土壤中P素与土壤质地的关系则并不是很密切。研究表明,围垦及其利用引起的土壤水分和质地等物理性质的变化以及不同围垦历史是影响湿地土壤养分空间分布的主要因素。     

药雾浓度沉降曲线拟合方法的试验)(简报)

为了解温室大棚等密闭空间喷雾后的药雾浓度衰减规律,该文以常温烟雾机在棚室中喷雾后的药雾浓度为研究对象,针对D.K.Giles的药雾浓度沉降曲线拟合方法进行了改进,相对于老方法将采样时间段内获得的药雾浓度值置于中间时刻点进行拟合,新方法将该值分别对应于该时间段内3个不同时刻点进行拟合分析。新方法同时还建立了比较曲线拟合优劣的一种工程判据,据此判据得出在5 min的采样时间段条件下,将采样数据作为该采样时间段内第2 min时刻点的药雾浓度值,然后进行拟合,所得药物总质量和实际施用药物总质量相对误差最小,仅为1.6%。研究还表明,在浓度沉降过程中,某一采样周期内的浓度值主要由这一时间段的前段采样所贡献。     

吉安一次持续性平流辐射大雾天气成因分析

采用Micaps 3.1资料、赣州探空资料、宜春风廓线(WPRD,60 min)风场产品以及吉安自动观测系统资料,分析2012年11月18—19日吉安一次持续性平流辐射大雾天气过程的大尺度天气背景、动力和热力结构特征及其演变等,揭示了这次平流辐射大雾过程的形成和维持机制。结果表明,这是冷暖平流在有利条件下经过辐射冷却后形成的平流辐射雾。在有利的大尺度背景条件下,暖平流移动到冷的下垫面和冷平流移向较暖的近地层,同时地表净辐射进一步加强近地层冷却,是此次大雾过程的触发和加强机制。特殊的温度场结构增加了低层暖湿空气和下垫面之间的温差,近地层至低层弱的辐合和垂直上升运动有助于小风的维持和稳定;充足的水汽为大雾长时间维持提供了有利条件。近地层风速增大和低层逆温层、湿度层消失是这次连续性平流辐射雾消散的主要原因。     

广西莲雾冬季防寒及寒后管理技术

莲雾属于热带水果,温度低于10℃,果实及叶片生长停止；低于8℃,叶片出现冻害现象,花蕾及果实出现消蕾、落果现象。结合生产实际,提出果园覆盖、适时适量修剪、科学的水肥管理、病虫害防治等防寒及寒后管理措施,为广西莲雾的优稀特色水果生产提供参考,以期促进广西莲雾产业的发展。     

Historical change in coastal sage scrub in southern California,USA in relation to fire frequency and air pollution

Invasions resulting in the transformation of one ecosystem to another are an increasingly widespread phenomenon. While it is clear that these conversions, particularly between grassland and shrubland systems, have severe consequences, it is often less clear which factors are associated with these conversions. We resampled plots from the 1930s (Weislander VTMs) to test whether two widely assumed factors, changes in fire frequency and nitrogen deposition, are associated with the conversion of coastal sage scrublands to exotic grasslands in southern California. Over the 76-year period, coastal sage scrub cover declined by 49%, being replaced predominantly by exotic grassland species. Grassland encroachment was positively correlated with increased fire frequency and, in areas with low fire frequencies, air pollution (percent fossil carbon as indicated by ∂¹⁴C, likely correlated with nitrogen deposition). We conclude that increases in fire frequency and air pollution over the last several decades in southern California may have facilitated the conversion of coastal sage shrubland to exotic grassland systems.     

Modeling tsunami damage in Aceh: a reply

In reply to the critique of Baird and Kerr, we emphasize that our model is a generalized vulnerability model, built from easily acquired data from anywhere in the world, to identify areas with probable susceptibility to large tsunamis—and discuss their other criticisms in detail. We also show that a rejection of the role of trees in helping protect vulnerable areas is not justified in light of existing evidence.     

应用生物防治棉蝗及星天牛——沿海防护林木麻黄病虫害综合控制技术研究报告

本研究筛选出蝗虫微孢子虫、蜡状芽孢杆菌及簇孢霉等微生物杀虫剂,并应用于防治棉蝗的感染率达77% 以上;应用从星天牛中分离的白僵菌防治星天牛,感染率达77.8% ;应用芜菁夜蛾线虫和蠹蛾线虫防治星天牛,感染率达90% 以上。为沿海防护林木麻黄病虫害的综合控制提供科学依据。     

气候因子和地表覆盖对沿海滩涂土壤盐分动态的影响

为探明气候因子对沿海滩涂表层土壤盐分季节性变化规律的影响,并探讨植被和秸秆覆盖对滩涂土壤脱盐效果及控盐的作用。2014年5月—2015年5月,在江苏沿海滩涂盐碱地(中重度盐分),设置4种处理进行田间试验,分别为对照(裸地,CK)、秸秆覆盖(覆盖量为15 t·hm-2,SM)、植被覆盖(PC)和植被+秸秆覆盖(覆盖量为7.5 t·hm-2,PC+1/2SM),监测了气候因子和表层土壤盐分的季节性动态变化。结果表明:1)在沿海滩涂裸地中,土壤盐分具有一定程度的季节性规律,表现为在10—12月具有明显的积盐效果,且在10月EC1︰5达到最大值为3.90 d S·m-1。2)相关分析表明:采样前7 d降雨累积量与土壤盐分变化有着极密切负相关关系;气候因子的多因子及互作逐步分析表明:降雨量增加可以促进土壤脱盐作用,大气温度升高可加剧土壤盐分表聚,降雨量和大气温度的互作效应增加会对土壤盐分累积产生正效应。3)地表覆盖(包括PC和SM)显著地改变了气候因子对土壤盐分动态变化的影响,累积降雨量和大气平均温度与土壤盐分无显著相关性,且大量秸秆覆盖对滩涂表层土壤脱盐具有更明显的效果。因此,在沿海气候向暖湿方向发展的趋势下,综合考虑脱盐及控盐作用,选择适量秸秆覆盖(如覆盖量15 t·hm-2)或适量秸秆覆盖结合植被种植覆盖,同时充分利用沿海地区降雨量集中的特点,可能是未来滩涂盐碱盐渍土快速脱盐和土壤改良的重要措施。