Relationships between mercury body concentrations, standard metabolic rate, and body mass in eastern mosquitofish (Gambusia holbrooki) from three experimental populations
Relationships between mercury body concentrations, standard metabolic rate, and body mass in eastern mosquitofish (Gambusia holbrooki) from three experimental populations
复制标题
三个实验种群的东部食蚊鱼（Gambusia holbrooki）体内汞浓度、标准代谢率和体重之间的关系
DOI：
--
复制
发表时间：
2003
影响因子：
4.1
通讯作者：
C. Jagoe
中科院分区：
文献类型：
--
作者：
W. Hopkins;Christopher P. Tatara;H. Brant;C. Jagoe
从三个实验种群（两个汞暴露种群和一个参考种群）中对东方食蚊鱼（Gambusia holbrooki）进行了采样，以确定跨代汞暴露（多代终身暴露）是否会对标准代谢率（SMR）产生不利影响。与参考种群的鱼类相比，终生接触汞的食蚊鱼在其组织中积累了大量的汞浓度（平均值分别为3.89-4.13和0.08 μHg/g湿重）。只有不到10%的汞组织浓度变异可以用鱼的体重来解释，这可能是因为该物种的寿命短和/或饮食习惯。尽管汞暴露的鱼类体内汞负荷很高，但我们发现汞暴露人群和参考人群的SMR没有显著差异。我们的研究结果对比最近的实验室工作描述了在食蚊鱼暴露于100 μg/L的溶解无机汞48 h后SMR升高。为了解释研究之间的对比结果，我们假设，急性暴露于溶解的无机汞损害鳃上皮细胞，导致代谢率增加，但终身汞暴露通过营养吸收甲基汞不影响鱼类的呼吸结构。另一种假设包括G. Holbrooki是一种能够耐受体内高汞负荷的物种，或者在汞暴露期间（8-12代）进行了四年多的遗传隔离，导致了对汞耐受或抗性个体的选择。
Eastern mosquitofish (Gambusia holbrooki) were sampled from three experimental populations (two Hg‐exposed populations and one reference population) to determine whether transgenerational exposure (lifelong exposure of multiple generations) to Hg adversely affects standard metabolic rate (SMR). Mosquitofish subjected to lifelong Hg exposure accumulated significant concentrations of Hg in their tissues compared to fish from the reference population (mean: 3.89–4.13 vs 0.08 μHg/g wet mass, respectively). Less than 10% of the variability in Hg tissue concentrations could be explained by fish body mass, likely because of the short life span and/or dietary habits of this species. Despite the high body burdens of Hg in exposed fish, we found no significant difference in SMR among individuals from Hg‐exposed or reference populations. Our findings contrast recent laboratory work describing elevated SMR in mosquitofish exposed to 100 μg/L dissolved inorganic Hg for 48 h. To account for contrasting results between studies, we hypothesize that acute exposure to dissolved inorganic Hg damages gill epithelium, resulting in increased metabolic rate, but that lifelong Hg exposure via trophic uptake of methyl mercury does not affect fish respiratory structures. Alternative hypotheses include the possibility that G. holbrooki is a species that can tolerate high body burdens of Hg or that more than four years of genetic isolation during Hg exposure (8–12 generations) resulted in selection for Hg‐tolerant or ‐resistant individuals.