闽南山区连续年龄序列桉树人工林土壤养分动态

对闽南山区连续年龄序列(2 a、3 a、4 a、5 a、6 a)的尾巨桉(Eucalyptus urophyllaxE.grandis)人工林土壤有机碳及氮、磷、钾含量进行了分析,以评价土壤养分随林分年龄的变化动态.土壤有机碳、全氮、水解氮、全磷、速效磷均表现出随林分年龄增加而增加,到4 a生时达到最大,随后则呈下降趋势,6 a生时下降到最低值.速效钾含量则随林分年龄增加逐步下降,6 a生林分0～20 cm、20～40 cm和40～60 cm这3个土层速效钾含量分别比2 a生下降了53.2%、44.4%和55.2%;土壤全钾含量也表现出一定的下降趋势.所有年龄林分的土壤有机碳、全氮、水解氮、全磷、速效磷和速效钾含量均随土层深度增加而降低,而土壤伞钾则表现出相反的趋势.因此,在桉树人工林经营过程中,应定期增施钾肥,适时施用有机肥及氮、磷肥,以控制地力衰退.图4表2参24     

塔里木盆地南缘绿洲土壤酶活性与理化因子相关性

基于塔里木盆地南缘于田绿洲土壤酶活性与水盐、养分等理化因子数据,利用冗余分析技术(RDA)全面分析了土壤酶活性与理化因子间的关系. 结果显示:①于田绿洲土壤酶活性总体水平较低,过氧化氢酶(以KMnO₄计)、转化酶(以Na₂S₂O₃计)、脲酶(以NH₃-N计)和碱性磷酸酶(以C₆H₆O计)活性平均值分别为9.37、2.04、0.27和0.18 mg/g;研究区土壤水分含量(15.46%,以w计)较少且盐渍化严重〔w(全盐)平均值为19.39 g/kg〕. ②w(有机质)、土壤水分含量、地下水埋深和w(有效磷)是影响土壤酶活性的主要因素,w(有机质)、土壤水分含量、w(有效磷)与土壤酶活性呈正相关,地下水埋深与土壤酶活性呈负相关. ③各理化因子对土壤酶活性影响的重要性排序为w(有机质)、土壤水分含量、地下水埋深、w(有效磷)、pH、w(全盐)、电导率、w(速效钾). 综合分析表明,研究区强盐渍化的土壤性质对土壤酶活性的抑制并不显著,土壤碳、磷等养分与水分状况才是限制土壤酶活性的关键因素.      

Comparing earthquake insurance programmes: how would Japan and California have fared after the 2010–11 earthquakes in New Zealand?

Earthquakes are insured in high-risk high-income countries only if the public sector is involved. Prototypical examples are the insurance schemes in California (United States), Japan, and New Zealand, but each is structured differently. This paper examines these variations using a concrete case study: the sequence of earthquakes in Christchurch, New Zealand, in 2010–11—the most heavily insured seismic event in history. It assesses what would have been the outcome had the Christchurch insurance system been different, focusing on the California Earthquake Authority (CEA) programme and Japan Earthquake Reinsurance (JER). Overall, the aggregate cost of the earthquake to the New Zealand public insurer (Earthquake Commission) was USD 6.2 billion. If a similar-sized disaster had occurred in Japan and California, homeowners would have received around USD 1.6 billion and USD 0.7 billion, respectively. This paper describes the distributive and spatial patterns of these scenarios and discusses some key policy questions that emerge from this comparison.     

Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California

Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire.     

Was Contamination of Southern California Groundwater By Chlorinated Solvents Foreseen?

The historical record does not support the argument that the cause of widespread groundwater contamination by chlorinated solvents in southern California was an inability to anticipate or detect the problem. The propensity of industrial wastes, including chlorinated solvents, to contaminate groundwater was understood by the 1940s in southern California. This understanding was not limited to a small group of specialists, but extended to regulators, industry, and the interested public. Industrial waste disposal was deregulated in 1949 as a result of lobbying by industry, despite a warning from the director of the State Health Department that such action would create "a backlog of water pollution over the State that will constitute a plague comparable to the air pollution in Los Angeles". Regulators warned specifically about the danger that groundwater pollution in the San Fernando and San Gabriel valleys would result from improper disposals of industrial chemicals, and solvents were identified as major contaminants in the scientific literature. Analytical methods to detect chlorinated solvents in groundwater at the concentrations found near the DNAPL (dense non-aqueous phase liquids) source zones have been well known since at least 1950, and a method with a detection limit of 10 w g/L was published as early as 1953.     

Public Nutrition from an Approach to a Discipline: Concern's Nutrition Case Studies in Complex Emergencies

The Public Nutrition approach, like that of Public Health, is context specific. It places an emphasis on populations rather than individuals and is inter-disciplinary in nature. Both approaches seek to understand the complex aetiology of a clinical outcome such as malnutrition within the widest possible framework. Public Nutrition uses the UNICEF conceptual framework and adapts and expands it. The authors of this article argue – through the examination of a number of case studies taken from the work of Concern Worldwide (hereafter referred to as Concern) in southern Sudan, Rwanda, Angola, Tanzania and DRC – that there are two critical constituents of the Public Nutrition approach. These are: a contextual analysis (including the use of surveillance information for programme design and advocacy) and community involvement at all stages of the project cycle. Some of the key obstacles to the adoption of the Public Nutrition approach are identified by illustrating two practical programme settings. For the Public Nutrition approach to be more widely used, the authors recommend a number of key strategies including the further dissemination of case studies and the clarification of the scope and boundaries of the approach. These strategies will enable Public Nutrition to evolve both as a practical programme framework as well as an academic discipline.     

南方冬季条件下根际促生菌与肥料配施对巨菌草迁移累积镉砷的影响

优良菌种是微生物肥料的基础,研究微生物肥料中低温适应型菌株在低温条件下的促生性,对于提高南方冬闲时植物修复重金属污染农田具有重要意义.通过形态观察及18S rRNA基因序列分析,对菌株进行了鉴定,在此基础上进行植物盆栽试验,分析了3株不同根际促生菌单独施加及其与肥料（鸡粪+微量元素）配施对镉砷复合污染土壤中巨菌草迁移累积Cd、As的影响.分离菌株的初步鉴定结果表明,3株根际促生菌（M1、M2、M3）分别为云南木霉（Trichoderma yunnanense）、卵形孢球托霉（Gongronella butleri）、越橘间座壳菌（Diaporthe vaccinii）.纯培养试验表明,M1、M2、M3均可在南方冬季低温条件下生长.盆栽试验结果表明,与CK处理相比,单独施菌或肥料及菌株与肥料配施均能提高巨菌草茎叶生物量,分别提高14.12%~84.35%、13.36%、57.25%~143.13%.在所有处理中,M3与肥料配施后,植株茎叶生物量达到最大.不同处理可影响巨菌草对Cd和As的吸收累积,但对巨菌草各部位影响不同.单独施菌时,M3对巨菌草茎叶Cd、As积累量提升最多,分别提高145.83%、64.03%;当菌株与肥料配施时,M3与肥料配施对巨菌草茎叶Cd、As积累量提升最多,分别提高94.17%、142.45%.可见,3株根际促生菌在南方冬季均能提高巨菌草生物量,其中,菌株M3与肥料配施具有开发为有效治理镉砷复合污染土壤的微生物肥料的良好前景.     

南海南部海域浮游细菌群落特征及影响因素研究

采用高通量测序技术,对南海南部海域浮游细菌丰度、群落组成和群落多样性的分布特征及与环境因子的关系进行了研究.结果表明,该研究区域浮游细菌丰度为107~108个/L,近岸大于离岸,同一站位不同水层细菌分布差异明显.优势类群为变形菌门、蓝藻门和拟杆菌门,优势亚群为 γ-变形菌纲、α-变形菌纲、蓝藻菌纲和黄杆菌纲,研究区域内不同水体间物种组成存在较大差异,另外该海域还存在大量未被认知的细菌类群.该海域浮游细菌种类丰富,具有较高的多样性指数(H￠)(4.44~7.00),研究区域内表层水体H￠接近,分别为5.26、5.33和5.07,处于上升流的次表层水体中H￠为6.70明显高于其他水层.DOC和磷酸盐是影响该海域浮游细菌丰度的主要因素,同时磷酸盐也是影响其群落多样性的主要因素,表明该海域异养浮游细菌生长主要受P的限制.     

基于后向轨迹模式的豫南地区冬季PM2.5来源分布及传输分析

为研究2017年12月—2018年2月冬季不同来源区域对豫南地区ρ（PM_2.5）的贡献影响及污染特征,利用HYSPLIT-4后向轨迹模式模拟了豫南地区冬季24 h的气团后向轨迹,结合ρ（PM_2.5）在线监测数据进行了聚类分析,研究了以豫南地区为受点的各月份PM_2.5不同轨迹的输送特征,并使用潜在源贡献（PSCF）分析法和浓度权重轨迹（CWT）分析法识别了豫南地区冬季PM_2.5的潜在贡献源区及贡献大小.结果表明:①信阳市空气质量最好,其次为驻马店市,南阳市空气质量最差;南阳市、信阳市和驻马店市ρ（PM_2.5）分别超过GB 3095—2012《环境空气质量标准》二级标准限值（75 μg/m3）的1.5、1.2和1.2倍,ρ（PM_2.5）日变化均呈双峰特征.②后向轨迹聚类分析表明,豫南地区主要受到来自西北和东北方向长距离传输和正南方向较短距离输送的影响.③潜在源区分析表明,除豫南地区及周边市县本地污染贡献外,冀鲁豫交界区域、陕鄂交界区域、陕西省中西部、湖北省东北部和西部、河南省中北部、山东省南部是影响豫南地区ρ（PM_2.5）的主要潜在源区.研究显示,豫南地区PM_2.5污染过程除了与地形条件、本地污染源排放有关外,来自东北、西北传输通道城市的远距离输送和南部的近距离传输也不容忽视.