Due to its persistence and potential ecological and health impacts, mercury (Hg) is a global pollutant of major concern that may reach high concentrations even in remote polar oceans. In contrast to the Arctic Ocean, studies documenting Hg contamination in the Southern Ocean are spatially restricted and large-scale monitoring is needed. Here, we present the first circumpolar assessment of Hg contamination in Antarctic marine ecosystems. Specifically, the Adélie penguin (Pygoscelis adeliae) was used as a bioindicator species, to examine regional variation across 24 colonies distributed across the entire Antarctic continent. Mercury was measured on body feathers collected from both adults (n = 485) and chicks (n = 48) between 2005 and 2021. Because penguins’ diet represents the dominant source of Hg, feather δ¹³C and δ¹⁵N values were measured as proxies of feeding habitat and trophic position. As expected, chicks had lower Hg concentrations (mean ± SD: 0.22 ± 0.08 μg·g^‒1) than adults (0.49 ± 0.23 μg·g^‒1), likely because of their shorter bioaccumulation period. In adults, spatial variation in feather Hg concentrations was driven by both trophic ecology and colony location. The highest Hg concentrations were observed in the Ross Sea, possibly because of a higher consumption of fish in the diet compared to other sites (krill-dominated diet). Such large-scale assessments are critical to assess the effectiveness of the Minamata Convention on Mercury. Owing to their circumpolar distribution and their ecological role in Antarctic marine ecosystems, Adélie penguins could be valuable bioindicators for tracking spatial and temporal trends of Hg across Antarctic waters in the future.

Graphical Abstract

中文翻译：

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汞污染的环极评估：阿德利企鹅作为南极海洋生态系统的生物指标

由于汞 (Hg) 的持久性和潜在的生态和健康影响，它是一种值得全球关注的污染物，即使在偏远的极地海洋中也可能达到高浓度。与北冰洋相比，记录南大洋汞污染的研究受到空间限制，需要大规模监测。在这里，我们对南极海洋生态系统中的汞污染进行了首次环极地评估。具体来说，阿德利企鹅 ( Pygoscelis adeliae)被用作生物指示物种，以检查分布在整个南极大陆的 24 个企鹅群的区域差异。对 2005 年至 2021 年间从成年企鹅 ( n  = 485) 和雏鸟 ( n  = 48) 收集的身体羽毛中的汞进行了测量。由于企鹅的饮食是汞的主要来源，因此羽毛 δ ¹³ C 和 δ ¹⁵ N 值的测量如下：摄食栖息地和营养位置的代表。正如预期的那样，雏鸡的汞浓度（平均值±标准差：0.22±0.08μg·g ^-1）低于成年鸡（0.49±0.23μg·g ^-1），这可能是因为它们的生物累积期较短。在成虫中，羽毛汞浓度的空间变化是由营养生态和群体位置驱动的。在罗斯海观察到汞浓度最高，可能是因为与其他地点（以磷虾为主的饮食）相比，饮食中鱼类的消耗量更高。此类大规模评估对于评估《水俣公约》的有效性至关重要。由于其环极分布及其在南极海洋生态系统中的生态作用，阿德利企鹅可能成为未来跟踪南极水域汞空间和时间趋势的有价值的生物指示剂。

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