Division of Environmental Science and Engineering, Pohang University of Science and Technology, 77 Cheongam-Ro, Nam-Gu, Pohang 37673, South Korea.
School of Marine Science and Policy, University of Delaware, Newark, Delaware 19716, United States.
Environ Sci Technol. 2024 Apr 9;58(14):6349-6358. doi: 10.1021/acs.est.3c09452. Epub 2024 Mar 26.
Mercury (Hg) biomonitoring requires a precise understanding of the internal processes contributing to disparities between the Hg sources in the environment and the Hg measured in the biota. In this study, we investigated the use of Hg stable isotopes to trace Hg accumulation in Adélie and emperor penguin chicks from four breeding colonies in Antarctica. Interspecific variation of ΔHg in penguin chicks reflects the distinct foraging habitats and Hg exposures in adults. Chicks at breeding sites where adult penguins predominantly consumed mesopelagic prey showed relatively lower ΔHg values than chicks that were primarily fed epipelagic krill. Substantial δHg variations in chick tissues were observed in both species (Adélie: -0.11 to 1.13‰, emperor: -0.27 to 1.15‰), whereas only emperor penguins exhibited the lowest δHg in the liver and the highest in the feathers. Our results indicate that tissue-specific δHg variations and their positive correlations with % MeHg resulted from MeHg demethylation in the liver and kidneys of emperor penguin chicks, whereas Adélie penguin chicks showed different internal responses depending on their exposure to dietary MeHg. This study highlights the importance of considering intra- and interspecific variations in adult foraging ecology and MeHg demethylation when selecting penguin chicks for Hg biomonitoring.
汞（Hg）生物监测需要精确理解导致环境中 Hg 源与生物群中 Hg 之间差异的内部过程。在这项研究中，我们研究了使用 Hg 稳定同位素来追踪南极洲四个繁殖地的阿德利企鹅和帝企鹅雏鸟中 Hg 的积累。企鹅雏鸟中 ΔHg 的种间差异反映了成鸟不同的觅食生境和 Hg 暴露情况。在成鸟主要摄食中层猎物的繁殖地，雏鸟的 ΔHg 值相对较低，而主要摄食表层磷虾的雏鸟则相对较高。两种企鹅的雏鸟组织中都观察到了大量的 δHg 变化（阿德利：-0.11 至 1.13‰，帝企鹅：-0.27 至 1.15‰），而只有帝企鹅的肝脏中 δHg 最低，羽毛中 δHg 最高。我们的结果表明，组织特异性 δHg 变化及其与 % MeHg 的正相关关系是由于帝企鹅雏鸟肝脏和肾脏中 MeHg 的脱甲基作用所致，而阿德利企鹅雏鸟则根据其对膳食 MeHg 的暴露情况表现出不同的内部反应。这项研究强调了在选择用于 Hg 生物监测的企鹅雏鸟时，考虑成鸟觅食生态学和 MeHg 脱甲基作用的种内和种间差异的重要性。
