Savannah River Ecology Lab, University of Georgia, Drawer E, Aiken, SC, 29802, USA.
Interdisicplinary Toxicology Program, University of Georgia, Athens, GA, 30602, USA.
Arch Environ Contam Toxicol. 2019 Oct;77(3):330-335. doi: 10.1007/s00244-019-00657-2. Epub 2019 Jul 26.
The global decline of amphibians is a major conservation issue. Many stressors are recognized for this decline including exposure to environmental contaminants. Mercury (Hg) is an environmental contaminant that bioaccumulates in wildlife and can cause a variety of negative impacts across taxa, including amphibians. Amphiuma and Siren spp. can comprise a large portion of biomass within their respective ecosystems, and thus, likely serve as important predators or prey in wetland communities. However, due to their cryptic nature, little is known about their ecology, diet, and accumulation potential. We sought to validate a nonlethal sampling method to quantify total mercury (THg) in two enigmatic species of aquatic salamanders: the two-toed amphiuma (Amphiuma means) and the lesser siren (Siren intermedia). We examined relationships between THg content in lethal (whole-body) and nonlethal (tail clip) samples. Tail clips were statistically significant predictors of whole-body THg (all p < 0.001), explaining 84-89% of variation in whole-body THg. Average whole-body THg (mg/kg) did not significantly differ between the two species (p = 0.97), and overall, they had similar whole-body THg content (S. intermedia = 0.330 ± 0.04, n = 18; A. means = 0.333 ± 0.07, n = 11). To our knowledge, these data represent the first reported Hg burdens in A. means and S. intermedia.
全球两栖动物数量的减少是一个主要的保护问题。许多压力因素被认为是导致这种减少的原因，包括暴露于环境污染物。汞（Hg）是一种环境污染物，在野生动物中生物积累，并可能对包括两栖动物在内的多个分类群造成各种负面影响。美洲蚓螈和小鳗螈在各自的生态系统中可能构成了很大一部分生物量，因此，它们可能是湿地群落中重要的捕食者或猎物。然而，由于它们的隐蔽性质，人们对它们的生态学、饮食和积累潜力知之甚少。我们试图验证一种非致死性采样方法，以量化两种神秘的水生蝾螈的总汞（THg）：两趾蚓螈（Amphiuma means）和小鳗螈（Siren intermedia）。我们研究了致死（全身）和非致死（尾巴夹）样本中 THg 含量之间的关系。尾巴夹是全身 THg 的统计学显著预测因子（所有 p<0.001），解释了全身 THg 变化的 84-89%。两种物种的全身 THg 平均值没有显著差异（p=0.97），而且它们的全身 THg 含量总体上相似（S. intermedia=0.330±0.04，n=18；A. means=0.333±0.07，n=11）。据我们所知，这些数据代表了首次报道的 A. means 和 S. intermedia 的 Hg 负荷。
