The relationship between contaminated sediments and deformity frequencies for benthic diatoms was the subject of this study. There were two basic types of diatom deformities observed in this study of Tolo Harbour dia...The relationship between contaminated sediments and deformity frequencies for benthic diatoms was the subject of this study. There were two basic types of diatom deformities observed in this study of Tolo Harbour diatoms: 1. Diatoms with deformed cell wall morphology and 2. diatoms with deformed ornamentation. Deformed individuals of Fragilaria capucina and Achananthes hauckiana Grun. displayed external cell wall deformities while deformed individuals of Diatoma displayed deformities in valve ornamentation. Abnormal cell morphology was used as an indicator of a degraded ecosystem. There was a significant correlation( P <0.05, r s=0.652) between sediment toxicity as reflected by the microtox test and benthic diatom diversity. Species diversity and species richness levels at the twelve sites were closely correlated with one another and inversely correlated with sediment toxicity as reflected by our microtox results( r s=0.809, P <0.01). The microtox test for acute toxicity was correlated ( P <0.05) with diatom species richness. The deformity frequencies and microtox tests were not significantly correlated. This lack of correlation was expected as in numerous laboratory studies, toxic substances were not necessarily mutagenic. The use of diatom deformity frequencies as a means of assessing the mutagenic/teratogenic impacts of anthropogenic substances on a marine benthic diatom community necessitates the enumeration of a large number of diatoms making this method extremely labor intensive.展开更多
文摘The relationship between contaminated sediments and deformity frequencies for benthic diatoms was the subject of this study. There were two basic types of diatom deformities observed in this study of Tolo Harbour diatoms: 1. Diatoms with deformed cell wall morphology and 2. diatoms with deformed ornamentation. Deformed individuals of Fragilaria capucina and Achananthes hauckiana Grun. displayed external cell wall deformities while deformed individuals of Diatoma displayed deformities in valve ornamentation. Abnormal cell morphology was used as an indicator of a degraded ecosystem. There was a significant correlation( P <0.05, r s=0.652) between sediment toxicity as reflected by the microtox test and benthic diatom diversity. Species diversity and species richness levels at the twelve sites were closely correlated with one another and inversely correlated with sediment toxicity as reflected by our microtox results( r s=0.809, P <0.01). The microtox test for acute toxicity was correlated ( P <0.05) with diatom species richness. The deformity frequencies and microtox tests were not significantly correlated. This lack of correlation was expected as in numerous laboratory studies, toxic substances were not necessarily mutagenic. The use of diatom deformity frequencies as a means of assessing the mutagenic/teratogenic impacts of anthropogenic substances on a marine benthic diatom community necessitates the enumeration of a large number of diatoms making this method extremely labor intensive.
