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41.
Rowland RH 《Soviet geography》1990,31(9):657-678
"This article investigates economic region net migration patterns in the USSR during the 1979-89 intercensal period. Net in-migration and net migration rate increases (compared to 1970-79) occurred in both the western and eastern portions of the Northern USSR region, while net out-migration and rate declines occurred throughout the Southern USSR. Net in-migration again occurred to Siberia, especially Tyumen' Oblast, and there was a reduced rate of net out-migration from the Nonchernozem Zone and Central Chernozem Region of European RSFSR." 相似文献
42.
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。 相似文献
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44.
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 相似文献
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48.
Sousa OV Macrae A Menezes FG Gomes NC Vieira RH Mendonça-Hagler LC 《Marine pollution bulletin》2006,52(12):1725-1734
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. 相似文献
49.
We assessed short-term ecological and potential human health effects of wastewater treatment plant (WTP) effluent by measuring δ15N‰ and microbial concentrations in oysters and suspended particulate matter (SPM). We also tested male-specific bacteriophage (MSB) as an alternative to fecal coliforms, to assess potential influence of wastewater contamination on shellfish. WTP effluent did not affect oyster growth or survival, but SPM and oysters acquired wastewater-specific δ15N‰. δ15N values were depleted near the WTP, typical of low-level processed wastewater. Fecal coliform and MSB concentrations were higher in samples taken closest to the WTP, and MSB values were significantly correlated with δ15N‰ in oyster tissues. Overall, oysters demonstrated relatively rapid integration and accumulation of wastewater-specific δ15N‰ and indicator microorganisms compared to water samples. These data suggest oysters were superior sentinels compared to water, and MSB was a more reliable indicator of wastewater influence on shellfish than fecal coliforms. 相似文献
50.
Golbuu Y van Woesik R Richmond RH Harrison P Fabricius KE 《Marine pollution bulletin》2011,62(4):824-831
Coral community structure is often governed by a suite of processes that are becoming increasingly influenced by land-use changes and related terrestrial discharges. We studied sites along a watershed gradient to examine both the physical environment and the associated biological communities. Transplanted corals showed no differences in growth rates and mortality along the watershed gradient. However, coral cover, coral richness, and coral colony density increased with increasing distance from the mouth of the bay. There was a negative relationship between coral cover and mean suspended solids concentration. Negative relationships were also found between terrigenous sedimentation rates and the richness of adult and juvenile corals. These results have major implications not only for Pacific islands but for all countries with reef systems downstream of rivers. Land development very often leads to increases in river runoff and suspended solids concentrations that reduce coral cover and coral diversity on adjacent reefs. 相似文献