The impact of shrimp farming effluent on bacterial communities in mangrove waters, Ceará, Brazil

The effects of shrimp farm effluents on bacterial communities in mangroves have been infrequently reported. Classic and molecular biology methods were used to survey bacterial communities from four mangroves systems. Water temperature, salinity, pH, total heterotrophic bacteria and maximum probable numbers of Vibrio spp. were investigated. Genetic profiles of bacterial communities were also characterized by polymerase chain reaction (PCR) amplification of eubacterial and Vibrio 16S rDNA using denaturing gradient gel electrophoresis (DGGE). Highest heterotrophic counts were registered in the mangrove not directly polluted by shrimp farming. The Enterobacteriaceae and Chryseomonas luteola dominated the heterotrophic isolates. Vibrio spp. pathogenic to humans and shrimps were identified. Eubacterial genetic profiles suggest a shared community structure independent of mangrove system. Vibrio genetic profiles were mangrove specific. Neither microbial counts nor genetic profiling revealed a significant decrease in species richness associated with shrimp farm effluent. The complex nature of mangrove ecosystems and their microbial communities is discussed.     

美国1987—1990年的大气电动力学

一、引言在1980年代后半期,对传统上的对流层电动力学和电离层电动力学的跨学科研究工作已有所加强。已有证据表明,雷暴电动力学对于中间层和电离层很重要。现在,我们对于电离层和磁层电流系统的下突情况的了解逐渐增多,对于覆盖了一些人称之为未知层的某个区域的中层大气电动力学的认识也     

初夏季风期中国大陆上热量与水汽的收支

利用天气尺度的控空与地面资料来计算１９８７、１９８８处１９８９年梅雨期前与梅雨期中国大陆上的热源与水汽汇。     

National and regional population trends in the USSR, 1979-89: preliminary results from the 1989 census

"This article investigates national, macroregional, and economic regional population trends in the USSR during the 1979-89 intercensal period based on preliminary results from the 1989 census. The national total population growth rate during 1979-89 was roughly similar to that of 1970-79. However, the urban growth and urbanization processes slowed, while the rate of rural population change increased due chiefly to reduced rural-urban migration. Regional variations in rates of total, urban, and rural population change generally resembled those of 1970-79. Central Asia continued to exhibit the most rapid overall growth, although Siberia experienced a resurgence."