Interactions between copper and cadmium modify metal organ distribution in mature tilapia, Oreochromis mossambicus

Sexually mature female tilapia were exposed to sublethal concentrations of waterborne Cu and/or Cd over 6 days, and subsequent body concentrations of these metals were determined in several organs. The results show that the distribution of Cu and Cd was metal and organ specific. This is demonstrated, for example, by the observation that in tilapia, Cu exposure did not result in Cu accumulation in the liver, whereas in the intestinal wall, notably high concentrations of Cu and Cd were measured in metal exposed fish. In addition to single metal exposed fish, we also determined Cu and Cd body distribution in Cu?Cd co-exposed fish. The observed interactions in metal accumulation were most pronounced in the organs of fish exposed to low, environmentally realistic, metal concentrations.     

Interactions between copper and cadmium modify metal organ distribution in mature tilapia, Oreochromis mossambicus

Sexually mature female tilapia were exposed to sublethal concentrations of waterborne Cu and/or Cd over 6 days, and subsequent body concentrations of these metals were determined in several organs. The results show that the distribution of Cu and Cd was metal and organ specific. This is demonstrated, for example, by the observation that in tilapia, Cu exposure did not result in Cu accumulation in the liver, whereas in the intestinal wall, notably high concentrations of Cu and Cd were measured in metal exposed fish.In addition to single metal exposed fish, we also determined Cu and Cd body distribution in Cu---Cd co-exposed fish. The observed interactions in metal accumulation were most pronounced in the organs of fish exposed to low, environmentally realistic, metal concentrations.     

盐池湾国家级自然保护区景观格局演变分析

景观格局演化是土地利用/覆盖变化和景观破碎化在时空上的直接表现,其时空演变过程和影响因素分析,对了解区域生态环境变化、维持生态系统平衡及可持续发展具有重要意义。该文基于1996、2006和2017年3期遥感影像,结合景观格局分析方法,对盐池湾国家级自然保护区近20年景观格局时空演变及影响因素进行分析。结果表明:1996-2017年盐池湾国家级自然保护区沼泽草地、沼泽地、冰川及永久积雪和沙地面积增幅分别为42.05%、63.24%、259.03%和87.62%,天然牧草地、河流水面和裸岩石砾地面积降幅分别为20.15%、24.33%和22.39%;斑块密度、最大斑块指数减小,斑块形状趋于简单,连通性增强,景观的破碎化程度降低;降水与冰川及永久积雪和裸岩石砾地呈显著相关(P<0.05),气温与各土地覆被类型之间关系不显著(P>0.05)。在自然和人为活动共同作用下,盐池湾国家级自然保护区的景观格局向连通性高、破碎化程度降低的方向演变。     

Changes in morphology and growth of the mudskipper (Periophthalmus argentilineatus) associated with coastal pollution

In this paper a comparison is made between the growth and morphology of barred mudskippers (Periophthalmus argentilineatus) from six mangrove forests along the coast of Tanzania. The fish populations from unpolluted sites consisted of different size classes, whereas only small sized fish were present in the polluted Mtoni mangroves. Age estimation based on the examination of otoliths revealed that the mudskippers followed similar growth patterns in all sites with limited pollution. However, the age estimates from the polluted Mtoni site revealed an abnormal growth pattern. The occurrence of unilateral anophthalmia in the Mtoni mudskippers suggested that these fish were affected by pollutants during early development. The study showed that the presence of urban and industrial wastes from Dar es Salaam city, as indicated by isotopic enrichment, correlated with abnormal growth and developmental effects in mudskippers. We hypothesize that pollution might also affect fish species that use the mangroves as a temporary habitat.