The Nature of Biodegradation of Vegetation in Mangrove Ecosystem

Experiments were carried out in situ and in the laboratory for 45 and 90 day periods respectively to study the nature and process of biodegradation of leaves/cladodes of 9 species of halophytes with special reference to mangrove vegetation. The leaching rate of chlorophylls a, b, bacteriochlorophylls a, c, d, phaeopigments, organic carbon and micronutrients such as Zinc, Copper. Iron and Manganese were studied at different intervals (10, 30, 90 days) and in varying salinity media (0.30, 16.60, 33.30%_°S). The organisms involved in fragmentation, decomposition and biodeterioration have been listed. Total litter production in the wooded mangrove area was 7,457.07 tonnes/year (leaf litter alone 5,834.4 tonnes/year). The mangroves export substantial organic material to the neighbouring estuarine and sea waters and the values were estimated at 261 tonnes C/year and 1,566 tonnes C/year respectively. Only 783 tonnes C/year were utilised and retained for use within the mangrove ecosystem.     

弱粘煤低温氧化活性基团与热效应的研究*

为研究煤氧化过程中活性基团的演变规律及热效应的变化特征,利用原位红外实验装置,实时测量煤升温过程中官能团的动态变化,数据处理得到弱粘煤红外波谱图,利用差减法对特征温度点下的红外光谱图进行处理,得到煤样的差示光谱,计算特征温度点下的红外结构参数;采用差示扫描量热仪,测量煤氧化过程中热流的变化,得到弱粘煤的热流曲线图,并对热流曲线进行阶段划分和氧化动力学计算。结果表明:弱粘煤中芳环数量比较少,环周围侧链较长,内部结构疏松,内部毛细管比较发达,内表面积较大,更容易发生自燃;整个氧化过程中羟基最为活跃,含氧官能团次之,其次是脂肪烃;红外参数计算结果HAL,I2整体呈减小趋势,I1,I3整体呈增大趋势;弱粘煤放热阶段的活化能值为25.12～61.26 kJ/mol,并随着升温速率的增大而减小,与此阶段放热量随升温速率的增大而增大相对应。     

Study of physico-chemical characteristics of water bodies around Jaipur

The present study has been undertaken to evaluate physico-chemical parameters (pH, temperature, dissolved oxygen, free carbon dioxide, alkalinity and hardness) and zinc concentration in water bodies in and around Jaipur. Water samples from Jalmachal Lake, Nevta Lake, Amer Lake and Ramgarh Lake were analysed. Results reveal that the water of Jalmahal Lake is most polluted due to high pH, hardness, alkalinity, free carbon dioxide, zinc content, and a low level of dissolved oxygen. Contrarily Ramgarh Lake is least polluted, as it has high dissolved oxygen and low pH, alkalinity, free carbon dioxide, hardness and zinc content.     

A survey of environmental features in a section of the Vellar-Coleroon estuarine system,south India

A survey was conducted on 15th November, 1970, in mangrove forests and backwater regions of a section of the Vellar-Coleroon estuarine complex; a total of 19 stations were occupied. Detailed investigations on nutrients, pigments, and plankton were carried out. The following ranges in values were recorded: salinity, 10.40 to 30.50; pH, 7.50 to 8.30; temperature, 29.50° to 30.50°C; total phosphorus, 0.72 to 3.34 g at/l; inorganic phosphate, 0.19 to 1.59 g at/l; ammonia, 0.34 to 0.36 g at/l; nitrite, 0.11 to 0.25 g at/l; nitrate, 2.85 to 6.94 g at/l; silicate, 18.49 to 134.92 g at/l. Dissolved oxygen content ranged from a minimum of 3.69 ml to a maximum of 5.44 ml/l. Chlorophyll a ranged from an undetectable amount to 1.01 mg/m³, chlorophyll b from 0.02 to 0.85 mg/m³, chlorophyll c from 0 to 0.41 mg/m³ and carotenoids from 0 to 0.74 MSPU/m³. The plankton displacement volume ranged from a negligible amount to 3.60 cm³/m³; seston varied between 0.29 and 0.91 g/l. Phytoplankton was abundant at 3 stations; at other stations zooplankton was abundant. Coscinodiscus, Asterionella and Ditylum were the dominant forms among the phytoplankton; Oithona, Acrocaanus, Euterpina, Centropages, Corycaeus, Lucifer and Oikocreura were dominant among the zooplankton. Phytoplankton and zooplankton populations, as percentage of the total plankton, varied between 3.70 and 89.00% and between 11 and 96.30%, respectively. Average gross production values in the mangrove and back-water stations were 7.56 and 3.33 g C/m³/day, and the net production values 6.29 and 2.67 g C/m³/day, respectively.     

博斯腾湖有色可溶性有机物来源及季节变化特征

博斯腾湖是中国西北地区最大的外流湖,近年来随着湖区周边废水排入量的增加,严重威胁到湖泊周边地区居民的饮用水安全.对博斯腾湖开展有色可溶性有机物（CDOM）的来源及季节变化研究对该湖水质保护具有非常重要的意义.通过平行因子分析法解析博斯腾湖CDOM三维荧光光谱,得到类腐殖酸组分C1（255 nm/420 nm）,类酪氨酸组分C2（270 nm/324 nm）和类色氨酸组分C3（230 nm/340 nm）.2018年夏季盐度与C1呈显著负相关（r=－0.64,p<0.01）,与C2呈显著正相关（r=0.65,p<0.01）,这表明河流等外界输入是夏季湖水中类蛋白质和类腐殖质荧光组分的主要来源,夏季强烈的蒸发作用使得微生物活性增强.而2019年秋季盐度与C3呈显著正相关（r=0.70,p<0.01）,与C2呈显著负相关（r=－0.51,p<0.05）,意味着淡水输入直接稀释河口区CDOM中的类蛋白组分.整体上,博斯腾湖CDOM浓度在黄水区附近最大,且夏季CDOM浓度较秋季更大（t-test,p<0.001）,意味着夏季水质更差.河口区各指标的变异程度较大,受淡水输入影响较其他湖区大,这在2018年夏季表现得尤为显著.博斯腾湖CDOM具有高度空间异质性,2018年夏季该湖西部入湖河口区C1组分的贡献较大且该组分贡献率向东部水体交换弱的湖区方向逐渐减小,相应C2组分的贡献率逐步增大.2019年秋季各荧光组分占比表现为由黄水沟河口区以C1为主向东部湖区快速转变为以C2为主.     

不同干扰方式对退耕弃荒地植被恢复的影响

由于各种原因,我国西部地区仍然分布着较大面积退耕后并未实现植被恢复的退耕弃荒地。不同方式或不同强度的人为干扰都会导致退耕弃荒地植被恢复效果发生偏差。研究选取滇西北维西县的退耕弃荒地为对象,通过分析放牧、围封和保护3类不同干扰方式下植被恢复过程中群落物种多样性、地上生物量及主要恢复使用树种云南松(Pinus yunnanensis)幼苗生长的差异,探讨不同干扰方式对退耕弃荒地植被恢复的影响。结果表明：放牧、围封和保护3种干扰方式下退耕弃荒地植物种的Margalef丰富度指数和Shannon-Wiener多样性指数大小均表现为围封样地＞保护样地＞放牧样地(P<0.05),即随着干扰强度的增加,群落物种的丰富度和多样性先升高后降低,结果支持“中度干扰假说”;退耕弃荒地植物群落地上生物量大小依次为保护样地＞围封样地＞放牧样地(P<0.001);云南松幼苗在不同干扰方式下的退耕弃荒地内生长优劣程度依次为保护样地＞围封样地＞放牧样地(P<0.001);因此,保护和围封方式均有利于退耕弃荒地的植被恢复,而自由放牧方式会阻碍植被恢复,甚至可能会导致植被退化。     

Distribution of improved cook stoves: analysis of field experiments using strategic niche management theory

Close to three billion people globally and over 800 million in India are dependent on direct combustion of unprocessed solid biomass fuels in inefficient traditional mud stoves. Current cooking practices, besides causing serious health problems, are also being linked to emissions of climate change and pollution agents such as black carbon and ozone precursors. In India several initiatives have been taken up to tackle the problem but the present trajectory of limited technical and social change in cooking energy use is nonetheless persistent in rural areas. In order to develop and scale up alternative cooking technology options, we have analyzed, using the principles of strategic niche management, two projects implemented by The Energy and Resources Institute (TERI) in nine villages in India. The assessment, while highlighting reasons for stability of the current cooking regime, also points to triggers that can destabilize the regime. The focus is also on assessing the influence of protection in the form of subsidies on the process of transition. User preferences relating to social and technical aspects have been analyzed, pointing to forced draft cookstoves as the preferred option notwithstanding cost reductions to address affordability concerns. The assessment indicates that while it is critically important to understand and address the preferences of users and to improve the technology, scaling up will depend on stove cost reduction through further research. Creativity in effective financing schemes and support structures put in place by fostering public–private partnerships are also needed.     

Lessons from the 2006 Louisiana health and population survey

The 2005 hurricane season caused extensive damage and induced a mass migration of approximately 1.1 million people from southern Louisiana in the United States. Current and accurate estimates of population size and demographics and an assessment of the critical needs for public services were required to guide recovery efforts. Since forecasts using pre-hurricane data may produce inaccurate estimates of the post-hurricane population, a household survey in 18 hurricane-affected parishes was conducted to provide timely and credible information on the size of these populations, their demographics and their condition. This paper describes the methods used, the challenges encountered, and the key factors for successful implementation. This post-disaster survey was unique because it identified the needs of the people in the affected parishes and quantified the number of people with these needs. Consequently, this survey established new population and health indicator baselines that otherwise would have not been available to guide the relief and recovery efforts in southern Louisiana.     

氧浓度对煤低温氧化热效应影响规律研究

为了准确掌握氧浓度对煤低温氧化热效应的影响,采用C80微量量热仪研究低温阶段煤氧化的自热过程,根据单升温速率的非等温动力学分析方法,得到不同氧浓度下煤样的活化能。研究结果表明:氧浓度对实验初始阶段的热流曲线和放热量的影响较小,随着温度的升高,氧浓度对热流曲线和放热量影响逐渐变得明显,放热趋势随着氧浓度的增大而增强;煤样的初始放热温度随着氧浓度的增大而降低;活化能随着氧气浓度的降低呈阶梯式上升;总放热量和氧浓度服从线性方程y=ax+b;与21%（空气气氛）氧浓度相比,15%,10%和5%氧浓度下煤的放热量分别降低了约19%,33%和46%,表明降低氧浓度对煤样的氧化放热具有明显的减缓作用。因此可以加强采空区的密闭性检测、注入惰性气体,使采空区的氧浓度尽可能地低,对采空区煤自热升温的防治有着理论指导意义。     

Photocatalytic degradation of the herbicide pendimethalin using nanoparticles of BaTiO3/TiO2 prepared by gel to crystalline conversion method: a kinetic approach

Photocatalytic degradation of the herbicide, pendimethalin (PM) was investigated with BaTiO3/TiO2 UV light system in the presence of peroxide and persulphate species in aqueous medium. The nanoparticles of BaTiO3 and TiO2 were obtained by gel to crystallite conversion method. These photo catalysts are characterized by energy dispersive x-ray analysis (EDX), scanning electron microscope (SEM), x-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) adsorption isotherm and reflectance spectral studies. The quantum yields for TiO2 and BaTiO3 for the degradation reactions are 3.166 Einstein m(-2) s(-1) and 2.729 Einstein m(-2) s(-1) and catalytic efficiencies are 6.0444 x 10(-7) mg(-2)h(-1)L2 and 5.403 x 10(-7) mg(-2)h(-1)L2, respectively as calculated from experimental results. BaTiO3 exhibited comparable photocatalytic efficiency in the degradation of pendimethalin as the most widely used TiO2 photocatalyst. The persulphate played an important role in enhancing the rate of degradation of pendimethalin when compared to hydrogen peroxide. The degradation process of pendimethalin followed the first-order kinetics and it is in agreement with Langmuir-Hinshelwood model of surface mechanism. The reason for high stability of pendimethalin for UV-degradation even in the presence of catalyst and oxidizing agents were explored. The higher rate of degradation was observed in alkaline medium at pH 11. The degradation process was monitored by spectroscopic techniques such as ultra violet-visible (UV-Vis), infrared (IR) and gas chromatography mass spectroscopy (GC-MS). The major intermediate products identified were: N-propyl-2-nitro-6-amino-3, 4-xylidine, (2, 3-dimethyl-5-nitro-6-hydroxy amine) phenol and N-Propyl-3, 4-dimethyl-2, 6-dinitroaniline by GC-MS analysis and the probable reaction mechanism has been proposed based on these products.