Monogenean Community Structure of Oreochromis Niloticus in Relation to Heavy Metal Pollution and Host Reproductive Cycle

2012 ◽  
Vol 42 (1) ◽  
pp. 11-24 ◽  
Author(s):  
Maha F. M. Soliman ◽  
Mohamed M. Ibrahim
1980 ◽  
Vol 37 (4) ◽  
pp. 647-655 ◽  
Author(s):  
R. W. Winner ◽  
M. W. Boesel ◽  
M. P. Farrell

Data from two streams suggest that macroinvertebrate community structure exhibits a predictable, graded response to heavy-metal pollution. In the more heavily stressed sections of both streams, macroinvertebrates, other than tubificid worms and chironomids, were virtually eliminated from rock-rubble, riffle habitats. Midge larvae comprised 75 to 86% of all insects collected from the most grossly polluted stations and less than 10% of the insect communities at the least polluted stations. The correlation coefficient for percentage of chironomids in relation to copper concentration was +0.93 (P ≤ 0.01). Changes in the coefficient of variation (CV) of percentage of chironomids per sample exhibited a consistent pattern. The lowest CV was at the most polluted stations and the CV increased along a gradient of decreasing metal concentrations, reaching maximum values at the least polluted stations. The number of species of chironomids was inversely related to the proportional density of the family in samples. In Elam's Run, the number of species of chironomids identified in samples increased from 15 at the most polluted station to 39 at the least polluted stations. Fifty-seven species of midges were collected along the 3-km stretch of this grossly polluted stream. Caddisflies were numerically important at the intermediately polluted stations in both streams. Mayflies occurred only at the least polluted stations. We hypothesize that heavily polluted habitats are dominated by midges, moderately polluted habitats by midges and caddisflies, and minimally polluted or unpolluted habitats by caddisflies and mayflies. Since there appears to be a direct relationship between the fraction of a community composed of chironomids and the degree of pollution, we suggest that the percentage of chironomids in samples may be a useful index of heavy-metal pollution.Key words: heavy metals, stream pollution, chironomids, aquatic insects


Author(s):  
Xingqing Zhao ◽  
Jian Huang ◽  
Xuyan Zhu ◽  
Jinchun Chai ◽  
Xiaoli Ji

The objectives of this study were to understand the characteristics of heavy metal pollution caused by mining activities on the two sides of the Shun’an river and the response of soil microorganisms to the habitats by different contamination levels and vegetation. This paper selected soil samples from the banks of the Shun’an River near the Shizishan mining area, which is at the left of the river, in Tongling, Anhui Province, China. Using Illumina MiSeq 2500 technology, we analyzed the relationship between environmental factors and microbial communities. As the distance from the mining area increased, the heavy metal comprehensive pollution and potential risk value decreased. Additionally, the pollution severity and risk value of the left bank, where the mining area lies, were generally higher than those of the right bank. Because the symmetric sampling points on both banks of the river had similar planting types, their environmental factors and microbial community structure were similar and clustered. However, under different vegetation, the paddy soils tended to have a higher nutrient content and community richness and diversity than the vegetable fields or the abandoned land. It was found that soil microbial communities in this area were mostly affected by pH and Nemerow pollution index (PN). The pH significantly affected the abundance and structure of most microorganisms. In addition, Proteobacteria, Acidobacteria, and Bacteroidetes had significant tolerance to Zn, Pb, and Cd. By exploring the potential use of these tolerant microorganisms, we seek to provide strains and the theoretical basis for the bioremediation of areas contaminated by heavy metal.


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