Landler Lukas, Painter Michael S, Coe Brittney Hopkins, Youmans Paul W, Hopkins William A, Phillips John B
Department of Biological Sciences, Virginia Tech, 1405 Perry Street, Blacksburg, VA 24061, USA.
Department of Fish and Wildlife Conservation, Virginia Tech, Blacksburg, VA 24061, USA; Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA.
Environ Pollut. 2017 Sep;228:19-25. doi: 10.1016/j.envpol.2017.04.050. Epub 2017 May 11.
The Earth's magnetic field is involved in spatial behaviours ranging from long-distance migration to non-goal directed behaviours, such as spontaneous magnetic alignment (SMA). Mercury is a harmful pollutant most often generated from anthropogenic sources that can bio-accumulate in animal tissue over a lifetime. We compared SMA of hatchling snapping turtles from mothers captured at reference (i.e., low mercury) and mercury contaminated sites. Reference turtles showed radio frequency-dependent SMA along the north-south axis, consistent with previous studies of SMA, while turtles with high levels of maternally inherited mercury failed to show consistent magnetic alignment. In contrast, there was no difference between reference and mercury exposed turtles on standard performance measures. The magnetic field plays an important role in animal orientation behaviour and may also help to integrate spatial information from a variety of sensory modalities. As a consequence, mercury may compromise the performance of turtles in a wide variety of spatial tasks. Future research is needed to determine the threshold for mercury effects on snapping turtles, whether mercury exposure compromises spatial behaviour of adult turtles, and whether mercury has a direct effect on the magnetoreception mechanism(s) that mediate SMA or a more general effect on the nervous system.
地球磁场参与了从长途迁徙到非目标导向行为（如自发磁取向，SMA）等各种空间行为。汞是一种有害污染物，大多源自人为活动，可在动物组织中终生生物累积。我们比较了从处于对照（即低汞）和汞污染场地捕获的母龟所孵化出的稚龟的自发磁取向情况。对照稚龟沿南北轴表现出依赖射频的自发磁取向，这与先前关于自发磁取向的研究一致，而具有高水平母体遗传汞的稚龟则未表现出一致的磁取向。相比之下，在标准性能指标方面，对照龟和接触汞的龟之间没有差异。磁场在动物定向行为中起着重要作用，还可能有助于整合来自各种感官模态的空间信息。因此，汞可能会损害龟在各种空间任务中的表现。未来需要开展研究，以确定汞对鳄龟产生影响的阈值、汞暴露是否会损害成年龟的空间行为，以及汞是否对介导自发磁取向的磁感受机制有直接影响，或者对神经系统有更广泛的影响。
