Canadian Rivers Institute and Biology Department, University of New Brunswick, Saint John, NB E2L 4L5, Canada.
Canadian Rivers Institute and Biology Department, University of New Brunswick, Saint John, NB E2L 4L5, Canada; Department of Earth and Environmental Science, Acadia University, Wolfville, NS B4P 2R6, Canada; Department of Biology, Acadia University, Wolfville, NS B4P 2R6, Canada.
Sci Total Environ. 2015 Mar 15;509-510:206-15. doi: 10.1016/j.scitotenv.2014.07.087. Epub 2014 Aug 19.
Recurring polynyas are important areas of biological productivity and feeding grounds for seabirds and mammals in the Arctic marine environment. In this study, we examined food web structure (using carbon and nitrogen isotopes, δ(13)C and δ(15)N) and mercury (Hg) bioaccumulation and biomagnification in a small recurring polynya ecosystem near Nasaruvaalik Island (Nunavut, Canada). Methyl Hg (MeHg) concentrations increased by more than 50-fold from copepods (Calanus hyperboreus) to Arctic terns (Sterna paradisaea), the abundant predators at this site. The biomagnification of MeHg through members of the food web - using the slope of log MeHg versus δ(15)N - was 0.157 from copepods (C. hyperboreus) to fish. This slope was higher (0.267) when seabird chicks were included in the analyses. Collectively, our results indicate that MeHg biomagnification is occurring in this small polynya and that its trophic transfer is at the lower end of the range of estimates from other Arctic marine ecosystems. In addition, we measured Hg concentrations in some poorly studied members of Arctic marine food webs [e.g. Arctic alligatorfish (Ulcina olrikii) and jellyfish, Medusozoa], and found that MeHg concentrations in jellyfish were lower than expected given their trophic position. Overall, these findings provide fundamental information about food web structure and mercury contamination in a small Arctic polynya, which will inform future research in such ecosystems and provide a baseline against which to assess changes over time resulting from environmental disturbance.
复发性冰间湖是北极海洋环境中生物生产力的重要区域，也是海鸟和哺乳动物的觅食地。本研究通过碳氮稳定同位素（δ(13)C 和 δ(15)N）和汞（Hg）生物累积和生物放大作用，调查了位于加拿大努纳武特纳撒鲁瓦利克岛附近的一个小型复发性冰间湖生态系统中的食物网结构。甲基汞（MeHg）的浓度从桡足类（Calanus hyperboreus）增加到北极燕鸥（Sterna paradisaea）增加了 50 多倍，北极燕鸥是该地区的主要捕食者。通过食物网成员（利用 logMeHg 与 δ(15)N 的斜率），MeHg 的生物放大率从桡足类（C. hyperboreus）到鱼类为 0.157。当将海鸟雏鸟纳入分析时，该斜率更高（0.267）。总的来说，我们的研究结果表明，MeHg 的生物放大作用正在这个小冰间湖中发生，其营养转移处于其他北极海洋生态系统估计范围的低端。此外，我们还测量了北极海洋食物网中一些研究较少的成员（如北极鳄鱼（Ulcina olrikii）和水母，刺胞动物）中的 Hg 浓度，发现水母中的 MeHg 浓度低于预期，考虑到它们的营养位置。总的来说，这些发现为小型北极冰间湖的食物网结构和汞污染提供了基本信息，这将为这些生态系统的未来研究提供信息，并为评估由于环境干扰而导致的随时间变化提供基线。
