Sources and Ecological Risks of Heavy Metals in Soils Under Different Land Uses in Bangladesh

Soil heavy metal pollution, influenced by both natural and anthropogenic factors, significantly reduces environmental quality. In this study, Cr, Ni, Cu, As, Cd, and Pb in eight different land-use soils from Patuakhali District in Bangladesh were assessed. Concentrations of Cr, Ni, Cu, As, Cd, and Pb in soils were 1-87, 5-271, 4-181, 0-80, 0.2-24.0, and 5-276 mg kg^-1, respectively, measured using an inductively coupled plasma-mass spectrometer. The enrichment factor, pollution load index (PLI), and contamination factor (C_fⁱ) of metal i were used to assess the ecological risk posed by metals in soils. The PLI ranged from 0.78 to 2.66, indicating baseline levels to progressive deterioration of soil due to metal contamination. However, C_fⁱ of Cd ranged from 1.8 to 12.0, which showed that the studied soils were strongly impacted by Cd. Considering the severity of the potential ecological risk of a single metal, the descending order was Cd > As > Pb > Cu > Ni > Cr. Soils under all land uses showed moderate to very high potential ecological risk.     

土壤硒富集空间分布特征及影响因素研究

以揭阳市土壤为对象,系统采集了表层土壤样(0～20 cm)1 330个和深层土壤样(150～200 cm)331个,并利用相关性分析、回归分析、方差分析及GIS空间分析技术等方法对土壤硒的含量分布、富集特征及影响因素进行了系统的分析。结果表明,揭阳市表层土壤Se含量处于0.02～2.01 mg/kg之间,几何平均值为0.48 mg/kg,是中国土壤Se平均含量的1.66倍。揭阳市土壤总体呈足硒及富硒特征,不存在硒过剩,极少区域土壤呈硒缺乏特征,表层与深层土壤表现基本一致,富硒土壤主要分布于普宁市、惠来县及北部边缘。表层土壤中Se富集面积达到52.03%,但在空间上分布零散,这可能与母质、土壤类型等因素有关。强富集区域集中分布于花岗岩与粉砂岩为母质的土壤区,而大部分由第四纪冲积物形成的土壤无富集。方差分析表明:不同母质、土壤类型及土地利用方式对土壤Se的含量及富集水平均造成不同程度的影响,其中影响揭阳市表层土壤Se含量的主要因素为成土母质。除此之外,土壤理化性质及海拔也是影响揭阳市表层土壤Se富集的重要因素。回归分析表明表层土壤Se与pH值呈极显著的负相关,并且分别与有机碳、Fe_2O_3及Al_2O_3呈极显著线性正相关。     

塔里木河下游胡杨气体交换对CO2加富和地下水埋深的响应

为了探讨CO2浓度增加对干旱荒漠区胡杨气体交换的影响,在塔里木河下游4个不同地下水埋深环境测定胡杨在CO2浓度分别为360,720μmol/mol条件下的光合速率、气孔导度、水分利用效率。结果表明,在地下水埋深4.12 m和4.74 m时,当CO2浓度由360μmol/mol增加到720μmol/mol时,胡杨的气孔导度略有减小;而在地下水埋深5.54 m和7.74 m环境下,CO2浓度的增加明显减小了胡杨的气孔导度。在CO2浓度为360μmol/mol时,胡杨的光合速率随着地下水埋深的增加而减少,然而当CO2浓度增加到720μmol/mol时,胡杨的光合速率不但没有因为地下水埋深的增加而减少,反而却因此而增加。当地下水埋深在4.12 m时,CO2浓度的增加对胡杨的水分利用效率没有产生明显的影响,但是随着地下水埋深近一步增加到4.74 m,5.54 m和7.74m时,胡杨的水分利用效率因CO2浓度的倍增分别增加了69%,18%和66%。地下水埋深最终控制着干旱荒漠区胡杨气体交换对CO2浓度升高的响应。     

A Comparison of the Effects of Two Prey Enrichment Media on Growth and Survival of Pacific Bluefin Tuna,Thunnus orientalis,Larvae

Three experiments were conducted to investigate the growth, survival, and standardized cohort biomass of Pacific bluefin tuna, Thunnus orientalis, larvae fed nutritionally enhanced prey during the first week of feeding using two commonly used, commercially available enrichment media, AlgaMac Enrich and Marine Glos. T. orientalis larvae exhibited exponential growth in standard length and dry weight. The daily specific growth rates in length and weight are the first reported for T. orientalis larvae and the averages ranged from 3.8 to 4.1% and 27.5%, respectively, for larvae in the AlgaMac treatment and from 4.1 to 6.1% and 31.5%, respectively, in the Marine Glos treatment. Average daily growth rates in length ranged from 0.16 to 0.23 mm/d for larvae in the AlgaMac treatment and from 0.17 to 0.27 mm/d for those in the Marine Glos treatment. Daily growth rates in length were similar to those reported for other tuna larvae reared in the laboratory but slower than most published estimates for larval tunas in situ at similar water temperatures. Mean prey number per gut was positively associated with mean prey level in the tank. Both enrichment media appear to be good sources of nutritional improvement of planktonic prey for T. orientalis larvae.     

Heat,wheat and CO2: The relevance of timing and the mode of temperature stress on biomass and yield

Atmospheric CO₂ enrichment affects C3 crops both directly via increased carbon gain and improved water use efficiency and indirectly via higher temperatures and more frequent climatic extremes. Here we investigated the response of spring wheat (Triticum aestivum L. cv. Triso) to CO₂ enrichment (550 vs. 380 µmol/mol) and heat, applied as a constant +4°C increase or a typical heat wave either before or after anthesis, or as two typical heat waves before and after anthesis. We applied a climate chamber approach closely mimicking ambient conditions. CO₂ enrichment increased above‐ground biomass and yield by c. 7 and 10%, but was not able to compensate for adverse heat stress effects, neither before nor after anthesis, with few exceptions only. Yield depression due to heat stress was most severe when two heat waves were applied (?19%). This adverse effect was, however, compensated by CO₂ enrichment. Applying heat stress before or after anthesis did not exert different effects on yield for both +4°C warming and heat wave application. However, +4°C depressed yield more than a heat wave at ambient CO₂, but not so at elevated CO₂. Thus, the interactive effects were complex and prediction of future wheat yield under CO₂ enrichment and climate extremes deserves more attention.     

二氧化碳浓度升高对茶树生理代谢的影响及应对技术

大气中的二氧化碳(CO2)浓度升高是工业革命以来全球范围内最重要的生态变化之一,将直接影响植物的生长发育和代谢过程。尽管CO2浓度升高对粮食作物的影响已经得到了广泛的研究,但其对茶树等重要经济作物的影响却很少受到关注。本文回顾和总结了CO2浓度升高对茶树的初级代谢(包括光合作用、呼吸作用和碳氮代谢)和次级代谢的影响,并探讨了CO2浓度升高环境下茶叶生产过程中的应对技术,旨在为CO2浓度升高背景下茶树优质高产栽培提供一定的理论基础和科学依据。     

互花米草入侵对滨海湿地重金属的富集迁移效应

为探究互花米草（Spartina alterniflora）入侵对滨海湿地沉积物重金属的富集迁移效应,为滨海湿地生态保护与合理利用提供依据,在山东省日照市黄家塘湾滨海湿地选取不同互花米草入侵年限的斑块,以5 cm为间隔采集0～30 cm沉积物样品和互花米草样品,分析沉积物和互花米草不同部位中重金属元素Cu、Zn、Pb和Cd的含量,并采用地累积指数法、潜在生态风险评价法、生物富集系数及转运系数等方法进行评价。结果表明：湿地沉积物重金属Cu、Zn、Pb和Cd 的含量范围为5.94～31.94 mg(kg^-1,18.59～56.87 mg(kg^-1,4.76～30.36 mg(kg^-1,0.021～0.083 mg(kg^-1,整体低于研究区域重金属环境背景值;但Cu、Pb在0～15 cm内存在轻度污染;与光滩湿地相比,互花米草入侵湿地沉积物中重金属含量增加,且随互花米草入侵年限增加,沉积物重金属含量呈增加趋势,在上层（0～15 cm）表现尤为显著;互花米草不同部位对重金属的累积存在一定差异,大致表现根>叶>茎;不同重金属在根部的富集效应表现为Cd > Zn > Cu > Pb,互花米草对重金属转运效应为Pb > Zn > Cu > Cd。相关分析表明,沉积物中重金属的累积与互花米草入侵对湿地沉积物粒度组成、有机质含量及pH的改变密切相关。不同重金属在沉积物-植物体系的迁移转运差异则主要与互花米草各部位对重金属元素的吸收差异有关。     

氨维营养强化剂的研究和利用

利用优质蛋白源—大豆饼粕强化谷物,通过粮豆蛋白质互补、生物强化和生物技术等方法,将营养价值较低的原料转化为营养丰富的组合食品—氨维营养强化剂。它氨基酸含量较高、组成比例较协调(接近 FAO 推荐值)。它含有包括人体必需的氨基酸共18种,多种维生素和矿质元素。经国内外有关专家品尝、鉴定,它是优质饮料和食品的强营养     

陕西省南部地区土壤粘粒特性研究

陕西南部土壤粘粒特性的研究发现,陕西省南部北亚热带湿润地区,发育在第四纪下蜀黄土母质上的土壤粘粒含量高,粘化层不明显,粘土矿物以伊利石和蒙脱石为主,粘粒铁富集明显;发育在基岩风化物母质上的土壤粘化层明显,粘土矿物以蒙脱石、蛭石为主,且有一定量的高岭石,粘粒中铝富集强烈。中山区暖温带湿润地区的土壤,粘粒含量较低,粘土矿物以伊利石、绿泥石为主,粘粒中铁、铝富集均不明显,元素的淋溶迁移较弱。     

粤北冰灾受损杉木林6种人工套种模式的植物多样性研究

基于2008年广东省天井山林场冰灾受损杉木林6种人工套种模式以及自然恢复模式的18个面积为400 m2样地的调查数据,对该区域受损杉木林的植物群落结构及其生物多样性进行了初步研究。结果表明,群落类型有杉木+红花荷、杉木+峨眉含笑、杉木+火力楠、杉木+枫香、杉木+南酸枣、杉木+观光木+深山含笑、杉木纯林。群落的乔木层常见树种为杉木、红花荷、峨眉含笑、火力楠、枫香、南酸枣、阿丁枫、观光木及深山含笑等;灌草层植物以蔓生莠竹、唐竹、山苍子、淡竹叶、空心泡等植物为优势种。各群落乔木层Shannon-Wiener指数从大到小依次为:杉木+观光木+深山含笑>杉木+红花荷>杉木纯林>杉木+枫香>杉木+南酸枣>杉木+火力楠>杉木+峨眉含笑;灌草层Shannon-Wiener指数由大到小依次为:杉木+红花荷>杉木+观光木+深山含笑>杉木+枫香>杉木+火力楠>杉木+峨眉含笑>杉木+南酸枣>杉木纯林。