Monitoring of Organochlorine Pesticide Residues in Summer and Winter Vegetables from Agra, India – A case study

Analysis of summer and winter vegetable samples during 2002–2003 for pesticidal contamination was carried out on Gas Chromatograph-Electron Capture Detector with capillary columns. The contamination levels of winter vegetables (average concentration of 4.57, 6.80 and 5.47 ppb respectively for Lindane, Endosulphan and DDT) were found to be slightly higher than the summer vegetables (average concentration of 4.47, 3.14 and 2.82 ppb respectively for Lindane, Endosulphan and DDT). The concentration of these organochlorine pesticides in summer and winter vegetables were well below the established tolerances but continuous consumption of such vegetables even with moderate contamination level can accumulate in the receptor's body and may lead to chronic effects that could be fatal.     

Winter Hydrology and NO3− Concentrations in a Forested Watershed: A Detailed Field Study in the Adirondack Mountains of New York1

Abstract: More than 85% of NO₃^? losses from watersheds in the northeastern United States are exported during winter months (October 1 to May 30). Interannual variability in NO₃^? loads to individual streams is closely related to interannual climatic variations, particularly during the winter. The objective of our study was to understand how climatic and hydrogeological factors influence NO₃^? dynamics in small watersheds during the winter. Physical parameters including snow depth, soil temperature, stream discharge, and water table elevation were monitored during the 2007‐2008 winter in two small catchments in the Adirondack Mountains, New York State. Snowpack persisted from mid‐December to mid‐April, insulating soils such that only two isolated instances of soil frost were observed during the study period. NO₃^? export during a mid‐winter rain‐on‐snowmelt event comprised between 8 and 16% of the total stream NO₃^? load for the four‐month winter study period. This can be compared with the NO₃^? exported during the final spring melt, which comprised between 38 and 45% of the total four‐month winter NO₃^? load. Our findings indicate that minor melt events were detectable with changes in soil temperature, streamflow, groundwater level, and snow depth. But, based on loading, these events were relatively minor contributors to winter NO₃^? loss. A warmer climate and fluctuating snowpack may result in more major mid‐winter melt events and greater NO₃^? export to surface waters.     

Mid‐Range Streamflow Forecasts Based on Climate Modeling – Statistical Correction and Evaluation1

Abstract: Mid‐range streamflow predictions are extremely important for managing water resources. The ability to provide mid‐range (three to six months) streamflow forecasts enables considerable improvements in water resources system operations. The skill and economic value of such forecasts are of great interest. In this research, output from a general circulation model (GCM) is used to generate hydrologic input for mid‐range streamflow forecasts. Statistical procedures including: (1) transformation, (2) correction, (3) observation of ensemble average, (4) improvement of forecast, and (5) forecast skill test are conducted to minimize the error associated with different spatial resolution between the large‐scale GCM and the finer‐scale hydrologic model and to improve forecast skills. The accuracy of a streamflow forecast generated using a hydrologic model forced with GCM output for the basin was evaluated by forecast skill scores associated with the set of streamflow forecast values in a categorical forecast. Despite the generally low forecast skill score exhibited by the climate forecasting approach, precipitation forecast skill clearly improves when a conditional forecast is performed during the East Asia summer monsoon, June through August.     

自然景观遥感解译基础上的华中自然区划研究

在自然景观类型的卫星图像解释和制图的基础上，通过对自然景观类型分布规律的定性分析和定量计算，自下而上归并与自上而下划分相结合，将华中地区划分为５个自然区、１９个自然亚区和３０个自然小区。     

石笋灰度和同位素对末次冰期气候事件的响应

对石笋多指标的研究有利于全面理解季风气候事件的变化特征和机制。以湖北永兴洞YX55石笋为研究对象,通过高精度U/Th定年和多指标分析重建了65~35 ka B.P.石笋灰度和稳定同位素的变化序列。在65~40 ka B.P.时段,石笋灰度、δ¹³C与δ¹⁸O都呈现出数个千年至亚千年尺度的变化,但δ¹³C变化幅度比δ¹⁸O小得多。这说明灰度和δ¹³C这类代表局域气候的指标,都响应于δ¹⁸O指示的Heinrich（H）事件和Dansgaard-Oeschger（DO）旋回,但响应的程度各不相同。H4期间,石笋δ¹³C和灰度呈现不一致变化：δ¹³C不像在其他H事件一样小幅振荡,而是大幅正偏（相当于其他H事件2~3倍）;灰度则显示出和DO旋回一致的特征。这种δ¹³C/灰度与δ¹⁸O异常响应关系可能的机制是：H4期间季风强度急剧减弱,使得洞穴上覆土壤覆盖率大幅降低,从而削弱或阻止了土壤—岩溶系统的过滤能力,使石笋中杂质含量异常增加。     

地表臭氧浓度升高对旱作农田N2O排放的影响

通过田间试验,在冬小麦和大豆生长季设置3种不同臭氧(O3)浓度的处理,包括自由空气(对照,CK)、100 n L·L-1O3浓度(T1)和150 n L·L-1O3浓度(T2),采用静态箱-气相色谱法测定N2O排放通量,研究地表O3浓度升高对冬小麦-大豆轮作系统N2O排放的影响.结果表明,与CK相比,在冬小麦返青期,T1和T2处理都降低了土壤-冬小麦系统N2O累积排放量,降幅分别为37.8%(P=0.000)和8.8%(P=0.903);在拔节-孕穗期,T1和T2处理使N2O累积排放量分别降低了15.0%(P=0.217)和39.1%(P=0.000);从冬小麦全生育期来看,T1、T2的N2O累积排放量分别降低了18.9%(P=0.138)和25.6%(P=0.000).由于本年度大豆生长季降水偏少,受干旱胁迫的影响,O3浓度升高对大豆田N2O排放的作用不明显.本研究表明地表O3浓度升高会减少旱作农田N2O排放量.     

增温及秸秆施用对冬小麦田土壤呼吸和酶活性的影响

为研究增温及秸秆施用对冬小麦田土壤呼吸和酶活性的影响,于2014-11~2015-05进行田间试验.设置对照、增温、秸秆施用、增温及秸秆施用这4个处理,观测了不同处理下土壤呼吸、土壤温度、土壤湿度(体积含水量)的季节动态,并在拔节期、孕穗期、扬花期观测了不同处理下的土壤脲酶、转化酶、过氧化氢酶活性.结果表明,对照、增温、秸秆施用、增温及秸秆施用这4个处理的季节平均土壤呼吸速率分别为1.46、1.96、1.92、2.45μmol·(m2·s)-1.方差分析表明,增温处理与对照、秸秆施用处理与对照、增温及秸秆施用处理与对照3对处理之间的季节平均土壤呼吸速率均存在显著差异(P0.05).不同处理下土壤呼吸与土壤温度的关系均可用指数回归方程拟合,指数回归方程可分别解释对照、增温、秸秆施用、增温及秸秆施用这4个处理土壤呼吸34.3%、28.1%、24.6%、32.0%的变异.增温、秸秆施用比对照处理显著(P0.05)提高了脲酶、转化酶、过氧化氢酶活性.土壤呼吸与脲酶活性存在线性回归关系,其P值为0.061,接近显著水平;土壤呼吸与转化酶(P=0.013)、过氧化氢酶活性(P=0.002)均存在极显著的线性回归关系.     

长三角地区春季臭氧污染特征及其对冬小麦产量的影响

春季是长三角地区对流层O₃污染的高峰期之一,高浓度的O₃暴露会影响冬小麦生长导致减产.利用长三角地区各城市2014年春季逐时ρ（O₃）观测数据,研究了长三角地区春季O₃污染特征,并结合O₃暴露指数（M7指数和AOT40指数）和剂量-响应关系模型,详细评估了长三角地区O₃污染对冬小麦产量的影响.结果表明:长三角地区春季ρ（O₃）空间上总体呈南低北高的分布,长三角地区北部江苏和上海的ρ（O₃）明显高于南部的浙江地区,在浙江北部、江苏和上海等地区,整个春季日最大8 h ρ（O₃）平均值超过107 μg/m3,最高值出现在5月,超过128 μg/m3;一半以上的城市ρ（O₃）超标[超过GB 3095-2012《环境空气质量标准》中8 h滑动平均ρ（O₃）的二级标准限值（160 μg/m3）]日数在10 d以上,其中南京和扬州超标日数最多,分别为27和20 d;相应地,O₃暴露指数也呈南低北高的分布,其中苏北地区O₃暴露指数最高,导致长三角地区平均冬小麦相对损失达5.7%（M7）~25.5%（AOT40）,造成的产量损失为7.85×105 t（M7）~4.49×106 t（AOT40）,其中,苏北地区为5.8%（M7）~25.9%（AOT40）,造成的产量损失为6.77×105 t（M7）~3.86×106 t（AOT40）,占长三角地区冬小麦产量损失的86%以上.研究显示,当前长三角地区O₃污染及其对冬小麦产量的影响已相当严重,特别是对苏北地区,而苏北地区是我国重要的冬小麦产地之一,因此,应当科学有效地治理O₃污染以缓解粮食安全问题.      

华北地区几种冬闲覆盖作物碳氮蓄积及其对土壤理化性质的影响

充分利用华北地区冬季空闲耕地及光热资源,以冬闲耕地为对照,研究二月兰（Orychophragmus violaceus）、毛苕（Vicia uillosa Roth.）、黑麦草（Secale cereale L.）、草木樨（Melilotus officinalis）、紫花苜蓿（Medicago satiua L.）5种不同冬闲覆盖作物地上部、地下部以及总碳、氮的蓄积量及其对土壤理化性质的影响。结果表明：5种覆盖作物总干物质质量在4.6-8.82 t.hm-2之间,是冬闲田干物质质量的1.6-3.1倍。5种覆盖作物全碳蓄积量在1.80-3.14 t.hm-2之间,是冬闲田碳蓄积量的1.9-3.3倍。与对照相比,各覆盖处理均明显提高氮素蓄积,尤以苜蓿最佳,达到了202.8 kg.hm-2,差异显著。试验选择5种肥覆盖均可提高土壤有机质质量分数（0.90-2.86 g.kg）;黑麦草覆盖可明显降低土壤容重（0.08 g.cm3）;毛苕和苜蓿栽培均可显著降低土壤pH,但同时土壤盐分有所增加;二月兰和黑麦草栽培在提高土壤水分含量方面表现最好。     

Composition and Some Ecological Features of Winter Zooplankton in Deep Stratified Lakes

For the first time, zooplankton and environmental factors have been studied in winter in the deep stratified lakes Siverskoe, Borodaevskoe, and Vydogoshch. The zooplankton consists of 18–22 species of rotifers, copepods, and cladocerans, including 15–18 specifically winter, cryophilic and eurythermic forms. The populations of zooplankters reproduce actively: males and egg-bearing females (in copepods), females with embryos and eggs in brood pouches (in cladocerans), and females with attached eggs (in rotifers) are present. In lakes Siverskoe and Borodaevskoe (depth 20–24 m), where oxygen deficiency is observed only in the bottom water layer, the zooplankton populates the greater part of the water column and forms a large aggregation in the oxycline and near the bottom. The abundance of bacteria in these zones is high (up to 4–6 × 10⁶ cells/ml). In Lake Vydogoshch (depth 16 m), oxygen deficiency extends to the middle layers, and all zooplankton is distributed above the oxycline. The biomass of winter zooplankton in Lake Siverskoe in 1983 averaged 1.26 g/m³, with a maximum of 4 g/m³; in 1993, 1.4 and 8.04 g/m²; the respective values in Lake Borodaevskoe were 0.98 and 3.1 in 1983 and 0.14 and 1.6 in 1993; in Lake Vydogoshch, 0.15 and 0.24 in 1983 and 1.25 g/m³ in 1993. The development of winter zooplankton is limited by the size of the zone of oxygen deficiency and depends on the amount of food (bacterioplankton). The distribution of zooplankton in the water column and its biomass in individual layers is determined by the rate of methane formation and oxidation.__________Translated from Ekologiya, No. 3, 2005, pp. 201–214.Original Russian Text Copyright © 2005 by Rivier.