澜沧江流域梯级水库建设下水体营养盐和叶绿素a的空间分布特征

澜沧江梯级水库群建设对流域水生态环境产生了一定的影响,将流域水体划分为自然河道段和水库段.为了探究梯级水库建设后澜沧江流域不同类型水体氮、磷营养盐和叶绿素a浓度的空间变化规律以及叶绿素a浓度与环境因子之间的关系,于2017年6月对澜沧江流域生态环境进行了调查分析.结果表明,澜沧江水体总氮质量浓度变化范围为0.37~1.22 mg·L^-1,均值为0.70 mg·L^-1;总磷质量浓度变化范围0.01~0.19 mg·L^-1,均值为0.04 mg·L^-1.单因素ANOVA分析表明,总氮空间差异显著,表现为支流段 > 水库段 > 自然河道段;但总磷没有明显的空间差异.澜沧江水库段水体叶绿素a浓度变化范围为2.6~10.2μg·L^-1,均值为5.8μg·L^-1.Pearson相关性分析结果显示,水体叶绿素a浓度与总磷浓度、水温和真光层与混合层之比（Z_eu/Z_mix）等具有显著相关性,其中与Z_eu/Z_mix的相关性最高（R²=0.689,P=0.001）,表明水温分层驱动下的Z_eu/Z_mix是影响澜沧江水库水体中浮游植物生长的关键性指标.     

填埋场原位好氧稳定化技术的应用现状及研究进展

综述了原位好氧稳定化技术的原理、系统构成、关键单元的设计和优化及终点评价,结合我国填埋场及垃圾特点,展望了该技术在我国的发展前景和挑战.均匀布气及配水是原位好氧稳定化项目实施过程中主要的难点.做好渗滤液导排保证堆体最优含水率、优化曝气及提气管道布局、分层整治并辅以高压局部曝气有望提高氧气利用率;采用分层回灌或者压力回灌以及控制回灌速率可分别改善液体回灌过程中的屏障效应和大孔隙出流效应,保障堆体布水均匀.好氧稳定化处理后垃圾腐殖土及场底土壤的风险评价体系及最终出路尚未明确,后期加强相关基础研究以指导工程应用是必要的.     

我国硝基苯的海水水质基准及生态风险评估研究

以一种重要的化工原料硝基苯为研究对象,通过收集、筛选我国本土物种的硝基苯海水生物毒性数据,同时针对我国海区生物特点补充8种典型海洋受试生物的毒理学实验,应用物种敏感度分布(SSD)方法推导了用于保护水生生物的我国硝基苯海水水质基准值。在此基础上,尝试应用2种概率生态风险评估方法初步评估了硝基苯在我国东海椒江口水体中的生态风险。研究结果表明,用于保护我国海水生物的硝基苯水质基准高值为1.42 mg·L-1,低值为0.037 mg·L-1,与应用SSD方法推导的硝基苯淡水水质基准差异不大。商值概率分布法和联合概率曲线法的风险表征结果表明,硝基苯对椒江口中的水生生物存在潜在的生态风险,需要管理部门采取一定的风险管控措施。研究结果有望为我国水质基准、生态风险研究及硝基苯的海水水质标准制定提供参考。     

秦岭中段撂荒地植被恢复过程中土壤微生物代谢特征

明确撂荒地植被恢复过程中土壤微生物养分限制特征及其驱动机制对揭示土壤养分循环和维持生态系统稳定具有重要意义.以秦岭中段不同年限撂荒地为研究对象,通过测定土壤理化性质、5种胞外酶活性[β-1,4-葡萄糖苷酶(BG)、纤维二糖水解酶(CBH)、β-1,4-N-乙酰基氨基葡萄糖苷酶(NAG)、亮氨酸氨基肽酶(LAP)和酸性磷...     

农用地土壤-作物系统对畜禽粪便养分消纳能力的评价

从土壤对养分消纳能力和作物养分需求角度出发,利用空间分析和地统计学方法,以北京市大兴区为例,进行了以地块为单元的农用地土壤-作物系统对畜禽粪便养分消纳能力评价.结果表明,大兴区农用地土壤-作物系统对畜禽粪便养分消纳能力整体一般,81.65%的农用地处于中下水平.除了因为大兴区的土壤保肥吸收能力整体不强外,还与大兴区的种植结构与种植面积有关,特别是高肥力的耕地与设施农业用地占地比例较小.     

规模化养殖场鸡粪营养物质和污染元素的组成特点

营养物质和有害元素的状况直接影响畜禽粪的利用价值.从浙江省代表性规模化养殖场收集19个鸡粪样,分析其营养物质、污染元素含量及P、Cu、Zn的化学形态.结果表明,鸡粪中含有较为丰富的粗蛋白和矿物质,但同时也含有较高量的Cu、Zn及可溶性盐分.鸡粪中P、Cu和Zn主要以可提取态存在,有较高的生物有效性和移动性.鸡粪中微量元素和重金属含量明显高于饲料,并受饲料中相应元素含量的影响;鸡粪与饲料之间的Ca、Mg、P、K、As、Cd、Cr、Cu、Fe、Mn、Pb和Zn含量显著相关,饲料质量是影响鸡粪重金属元素含量的主要因素.     

Is The Ca + K + Mg/Al Ratio in the Soil Solution a Predictive Tool for Estimating Forest Damage?

The ratio between (Ca +K +Mg) and Al in nutrientsolution has been suggested as a predictive tool forestimating tree growth disturbance. However, the ratiois unspecific in the sense that it is based on severalelements which are all essential for plant growth;each of these may be growth-limiting. Furthermore,aluminium retards growth at higher concentrations. Itis therefore difficult to give causal and objectivebiological explanations for possible growthdisturbances. The importance of the proportion ofbase-cations to N, at a fixed base-cation/Al ratio, isevaluated with regard to growth of Picea abies.The uptake of elements was found to be selective;nutrients were taken up while most Al remained insolution. Biomass partitioning to the roots increasedafter aluminium addition with low proportions of basecations to nitrogen. We conclude that the low growthrates depend on nutrient limitation in thesetreatments. Low growth rates in the high proportionexperiments may be explained by high internal Alconcentrations. The results strongly suggest thatgrowth rate is not correlated with the ratio in therooting medium and question the validity of usingratios as predictive tools for estimating forestdamage. We suggest that growth limitation of Picea abies in the field may depend on lowproportions of base cations to nitrate. It istherefore important to know the nutritional status ofthe plant material in relation to the growth potentialand environmental limitation to be able to predict andestimate forest damage.     

NUTRIENT LOAD CHARACTERIZATION FROM INTEGRATED SOURCE DATA FOR THE LOWER MISSISSIPPI RWER1

ABSTRACT: Nutrient data from all available sources for the lower Mississippi River were examined for potential differences among sampling agencies and geographic locations for the period between 1960 and 1998. Monthly means grouped by parameter, sampling location and agency, were calculated and compared as paired sets, excluding those months where data were not available for both sets. Some significant differences were found between various agencies collecting nutrient data on the river, as well as between various stretches of river, especially in the case of phosphorus nutrient data. Results were used to synthesize data sets from which a history of nutrient loading in the Mississippi River was determined. General trends in nitrate+nitrite, total Kjeldahl nitrogen, orthophosphate, total phosphorus and silica loads, as well as changes in nutrient proportions and the specific limiting nutrient (by month) are reported. This study provides a useful summary of contemporary and historical nutrient data that may assist in the evaluation of Mississippi River water quality and its potential effect on the Gulf of Mexico.     

微囊藻毒素-RR对烟草细胞活力及营养生理的影响

采用0.1,1.0,10.0μg/mL的微囊藻毒素-RR(MC-RR)处理烟草BY-2悬浮细胞,测定了细胞活力、细胞内蛋白质含量、可溶性糖含量、硝态氮含量及总磷含量,并且检测了酸性磷酸酶(ACP)的活力变化情况.结果表明,中、高浓度毒素处理细胞2d后,细胞活力及蛋白质含量与对照相比均显著下降.高浓度MC-RR处理降低了胞内可溶性糖的含量,暴露2d后仅为对照的45.57%;低浓度MC-RR处理在后期增加了胞内可溶性糖含量.高浓度毒素处理细胞4d后,细胞内硝态氮含量显著低于对照;中、低浓度毒素处理细胞7d后降低了胞内硝态氮含量.3组毒素处理均降低了胞内总磷含量,到实验结束时,低、中、高浓度处理组的胞内磷含量分别为对照的74.98%、76.47%和84.00%.3组处理组ACP活力与对照相比呈现先降低后升高的趋势.     

长江口及邻近海域表层沉积物中营养元素的分布特征及其控制因素

对2003年6月采集的长江口及邻近海域的24个表层沉积物样品进行分析,分别得到C、N、P三种营养元素的三种形态的含量,并由此得到不同形态营养元素的平面分布及其在总量中所占的份额,即IC、IP为C、P的优势形态,而ON为N的优势形态。在此基础上,进一步分析了影响不同营养元素分布的因素,得出上覆水体的温度、沉积物粒度以及水动力条件等对沉积物中营养元素的分布具有重要影响。