Institute of Oceanography, National Taiwan University, Taipei 10617, Taiwan;
Institute of Oceanography, National Taiwan University, Taipei 10617, Taiwan.
Proc Natl Acad Sci U S A. 2021 Sep 21;118(38). doi: 10.1073/pnas.2111205118.
Bluefin tuna (BFT), highly prized among consumers, accumulate high levels of mercury (Hg) as neurotoxic methylmercury (MeHg). However, how Hg bioaccumulation varies among globally distributed BFT populations is not understood. Here, we show mercury accumulation rates (MARs) in BFT are highest in the Mediterranean Sea and decrease as North Pacific Ocean > Indian Ocean > North Atlantic Ocean. Moreover, MARs increase in proportion to the concentrations of MeHg in regional seawater and zooplankton, linking MeHg accumulation in BFT to MeHg bioavailability at the base of each subbasin's food web. Observed global patterns correspond to levels of Hg in each ocean subbasin; the Mediterranean, North Pacific, and Indian Oceans are subject to geogenic enrichment and anthropogenic contamination, while the North Atlantic Ocean is less so. MAR in BFT as a global pollution index reflects natural and human sources and global thermohaline circulation.
蓝鳍金枪鱼（BFT）在消费者中备受推崇，它们会积累大量的汞（Hg），其中包括神经毒性的甲基汞（MeHg）。然而，目前尚不清楚全球分布的 BFT 种群中 Hg 的生物积累情况有何不同。在这里，我们发现 BFT 体内的汞积累速率（MAR）在地中海最高，然后依次为北太平洋>印度洋>北大西洋。此外，MAR 与区域海水中和浮游动物中 MeHg 的浓度成正比，这将 BFT 体内的 MeHg 积累与每个亚流域食物网底部的 MeHg 生物利用度联系起来。观察到的全球模式与每个海洋亚流域的 Hg 水平相对应；地中海、北太平洋和印度洋受到地球化学富集和人为污染的影响，而北大西洋则较少受到影响。BFT 体内的 MAR 作为全球污染指数反映了自然和人为来源以及全球热盐环流。
