Tiemannite (HgSe) is considered the end-product of methylmercury (MeHg) demethylation in vertebrates. The biomineralization of HgSe nanoparticles (NPs) is understood to be an efficient MeHg detoxification mechanism; however, the process has not yet been fully elucidated. In order to contribute to the understanding of complex Hg metabolism and HgSe NPs formation, the Hg isotopic signatures of 40 samples of 11 giant petrels were measured. This seabird species is one of the largest avian scavengers in the Southern Ocean, highly exposed to MeHg through their diet, reaching Hg concentrations in the liver up to more than 900 µg g^-1. This work constitutes the first species-specific isotopic measurement (δ²⁰²Hg, Δ¹⁹⁹Hg) of HgSe NPs in seabirds and the largest characterization of this compound in biota. Similar δ²⁰²Hg values specifically associated to HgSe (δ²⁰²Hg_HgSe) and tissues (δ²⁰²Hg_bulk) dominated by inorganic Hg species were found, suggesting that no isotopic fractionation is induced during the biomineralization step from the precursor (demethylated) species. In contrast, the largest variations between δ²⁰²Hg_bulk and δ²⁰²Hg_HgSe were observed in muscle and brain tissues. This could be attributed to the higher fraction of Hg present as MeHg in these tissues. Hg-biomolecules screening highlights the importance of the isotopic characterization of these (unknown) complexes.

Tiemannite (HgSe) 被认为是脊椎动物甲基汞 (MeHg) 去甲基化的最终产物。HgSe 纳米粒子 (NPs) 的生物矿化被认为是一种有效的甲基汞解毒机制；但是，该过程尚未完全阐明。为了有助于了解复杂的 Hg 代谢和 HgSe NPs 形成，测量了 11 只巨型海燕的 40 个样品的 Hg 同位素特征。这种海鸟物种是南大洋最大的鸟类食腐动物之一，通过它们的饮食高度接触到甲基汞，肝脏中的汞浓度高达 900 µg g ^-1以上。这项工作构成了第一个物种特异性同位素测量（δ ²⁰² Hg，Δ ¹⁹⁹Hg）在海鸟中的 HgSe NPs 以及该化合物在生物群中的最大表征。^{发现了与 HgSe (δ 202} Hg _HgSe ) 和以无机 Hg 物种为主的组织 (δ ²⁰² Hg _bulk ) 相关的类似 δ ²⁰² Hg 值，这表明在前体（去甲基化）物种的生物矿化步骤中没有诱导同位素分馏。相比之下，δ ²⁰² Hg _bulk和 δ ²⁰² Hg _{HgSe之间的最大变化}在肌肉和脑组织中观察到。这可归因于这些组织中以甲基汞形式存在的汞含量较高。汞生物分子筛选突出了这些（未知）复合物同位素表征的重要性。