海洋微藻对游离氨基酸的利用特性研究

分别以4种游离氨基酸——丙氨酸、甘氨酸、谷氨酸和天冬氨酸为唯一氮源,采用实验室一次性培养的方法,研究典型赤潮藻——东海原甲藻(Prorocentrum donghaiense)、球形棕囊藻(Phaeoecystis globosa)和米氏凯伦藻(Karenia mikimotoi)及常见种类中肋骨条藻(Skeletonema costatum)的生长特性、光合特征及对氨基酸的吸收动力学特征,以无机氮源硝氮、氨氮作为对照.研究结果表明,在无菌条件下,东海原甲藻和球形棕囊藻可以利用多种游离氨基酸快速生长,而米氏凯伦藻和中肋骨条藻在以游离氨基酸为唯一氮源条件下不能维持生长.东海原甲藻和球形棕囊藻在丙氨酸中的生长速率最高,天冬氨酸和谷氨酸次之,甘氨酸最低.氨基酸处理组的Fv/Fm值在培养后期降幅小、降速慢,且高于无机氮处理组.东海原甲藻和球形棕囊藻对丙氨酸的最大吸收速率和半饱和常数分别为3.32、0.41pmol·cell-1·h-1和6.99和20.54pmol·L-1.因此,海洋微藻对游离氨基酸的吸收利用具有显著的种间差异,东海原甲藻和球形棕囊藻具有更广的氮营养生态位,在近海有机污染不断加剧的背景下,更容易形成优势甚至暴发赤潮.     

哈市城乡结合部环境问题与保护对策

介绍了哈市道里区城乡结合部环境问题及成因,提出了保护对策。     

Bioassessment of Streams using Macroinvertebrates: Are the Chironomidae Necessary?

Median hardness and sodium levels in groundwater were calculatedfor 244 Texas counties from measurements at 7728 water wells.The data were mapped and analyzed with a geographic informationsystem (GIS). County median hardness levels varied widely, from4–2304 mg L^-1. More than 60% of the counties had hardnessmedians above 180 mg L^-1. County medium sodium concentrationsranged from 6–1170 mg L^-1, with more than 90% of those valuesexceeding 20 mg L^-1. There was a significant positive correlationbetween hardness and sodium concentrations in six of Texas' ninemajor aquifers. A significant negative correlation betweenhardness and sodium was observed in two aquifers. Severalfactors control hardness and sodium variations in Texas aquifers including rock/sediment composition, groundwaterchemical evolution, and seepage from nearby formations. Probablehuman controls include agricultural return flow andpumping-induced saltwater intrusion.     

The Path Analysis and Its Application Study on Cultivated Land Change in Hubei Province

On the basis of introducing the principle of path analy- sis, this paper positively analyzes the influence factors of culti- vated land change from 1978 to 2002 in Hubei Province. The relationship between the influence factors and cultivated land change is studied by means of the path analysis. The results show that the construction rearrangement of agriculture, grain security and market mechanism are the main factors that decide the culti- vated land change. Meanwhile, the impact of investment, urbani- zation and benefit gap among the different utilizing ways also leads to the change of cultivated land. The result means that though some factors have less direct influence on the change of cultivated land, their indirect influence is significant or vice versa.     

室内空气品质评价

介绍国内外有关室内空气品质的评价方法，着重介绍CFD和多区域两类模拟方法。     

"脱钩"评价模式及其对循环经济的影响

主要介绍西方研究经济增长与物质消耗关系的“脱钩”理论的两种主流评价模式：IU曲线和总量研究。通过对它们评价手段、评价过程的进一步比较、分析，作乾提出从理论推导和实际应用需求两方面看，利用IU曲线评价“脱钩”都存在一定的缺陷，应该对总量研究的评价模式给予更多关注，才能更深刻地体现循环经济实施过程中对可循环利用资源的需求迫切性。     

基于GTWR-XGBoost模型的四川省PM2.5小时浓度估算

卫星气溶胶光学厚度(AOD)和气象数据已被广泛用于估算空气动力学直径≤2.5μm的地表颗粒物(PM_2.5)浓度.研究高时间分辨率、高精度的PM_2.5浓度估算方法,对及时准确的空气质量预报和大气污染的预防及缓解具有重要意义.使用Himawari-8 AOD小时产品和ERA5气象再分析资料作为估算变量,提出GTWR-XGBoost组合模型,对四川省PM_2.5小时浓度进行估算.结果表明：(1)提出的组合模型运用于全数据集的性能优于KNN、 RF、 AdaBoost、 GTWR、 GTWR-KNN、 GTWR-RF和GTWR-AdaBoost模型,拟合精度指标R²、 MAE和RMSE分别为0.96、 3.43μg·m^-3和5.52μg·m^-3,验证精度指标R²、 MAE和RMSE分别为0.9、 4.98μg·m^-3和7.92μg·m^-3.(2)该模型作用于PM_2.5浓度小时估算...     

长江经济带矿山土壤重金属污染及健康风险评价

研究长江经济带矿山土壤重金属污染状况,是推动长江经济带矿山生态修复和绿色矿山建设的重要前提.通过搜集2006～2020年间长江经济带矿山土壤重金属污染相关研究,并对搜集文献采样数据运用地累积指数法、克里金插值法和健康风险评价法对重金属的污染状况、分布规律和健康风险进行研究.结果表明,长江经济带矿山土壤中Pb、 Cd、 Cr、 Hg、 As、 Zn、 Ni和Cu含量平均值超我国长江经济带土壤背景值,Cd和Hg累积程度显著;污染评价结果显示8种重金属污染程度大小为：Cd>Hg>Pb>Zn>Cu>As>Ni>Cr, Cd和Hg污染程度最高,存在超60%的样本点处于中污染以上;污染评价显示锡矿和铅锌矿土壤污染较其他矿种明显突出;健康风险评估显示经口摄入为非致癌和致癌风险的主要摄入途径,总非致癌和致癌风险指数均处于不可接受范围内,且长江经济带中上游各省市矿山土壤的非致癌和致癌风险明显高于下游.