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In the decades since Jensen's discovery, PCBs have been banned or regulated in many countries.[qh]
在詹森发现多氯联苯后的几十年里，多氯联苯在许多国家被禁止或受到监管。[qh]
But that does not mean they have disappeared. Instead, as the discovery of high concentrations of them in the bodies of amphipods recovered from the bottom of the Mariana and Kermadec trenches demonstrates, they have simply migrated into deeper waters.[qh]
但这并不意味着它们已经消失了。相反，从马里亚纳和克马德克海沟底部发现的片脚类动物体内高浓度的它们表明，它们只是迁移到更深的水域。[qh]
Exactly what this will mean is not yet fully understood.[qh]
这究竟意味着什么，目前还不完全清楚。[qh]
PCBs are highly toxic in even tiny doses, causing cancer, liver damage and deformities in many species as well as disturbing hormonal balances in fish, birds and mammals, and have been linked to neurological disorders in birds.[qh]
即使是很小的剂量，多氯联苯也有剧毒，会导致许多物种癌症、肝损伤和畸形，还会扰乱鱼类、鸟类和哺乳动物的荷尔蒙平衡，并与鸟类的神经系统疾病有关。[qh]
Because PCBs collect in fatty tissues they also accumulate as they move up the food chain, thus concentrating in the bodies of long-lived, high-level predators such as sharks, seals and whales,[qh]
由于多氯联苯在脂肪组织中聚集，它们在食物链的上行也会积累，从而集中在长寿的高级捕食者（如鲨鱼、海豹和鲸鱼）的体内，[qh]
where they have been implicated in mass die-offs of dolphins, and are known to result in increased mortality in whales and dolphins, who transfer high concentrations of them to their young in their milk.[qh]
它们与海豚的大规模死亡有关，并且已知会导致鲸鱼和海豚的死亡率增加，因为它们将高浓度的多氯联苯转移到它们的乳汁中给它们的后代。[qh]
Worse yet, PCBs break down extremely slowly when kept out of the sunlight, meaning they can linger in the deep ocean and the bodies of animals for decades or even longer.[qh]
更糟糕的是，多氯联苯在没有阳光的情况下分解得非常慢，这意味着它们可以在深海和动物体内停留数十年甚至更长时间。[qh]
Like the slow decay of the hundreds of thousands of tonnes of nuclear waste spread across the sea floor, the toxic legacies of human industry written into the bodies of ocean creatures are a reminder that the deep is not a place of forgetting, but an ark of memory.[qh]
就像遍布海底的数十万吨核废料的缓慢腐烂一样，人类工业遗留下来的有毒物质也刻在了海洋生物的身体里，提醒着我们，深海不是一个遗忘的地方，而是一个记忆的方舟。[qh]
And while its repositories contain a record of the spasm of environmental destruction over the past century or so, they also stretch back far beyond human timeframes.[qh]
虽然它的记忆储存中包含了过去一个世纪左右环境破坏的记录，但它们也远远超出了人类的时间框架。[qh]
A surprising amount of our understanding of the Earth's past climate is drawn from studies of the shells of ancient foraminifera, tiny, single-celled organisms often less than a millimetre in diameter that thrive in the mud on the sea floor or drift with other plankton near the surface.[qh]
我们对地球过去气候的了解，有相当一部分是来自对古代有孔虫壳的研究。有孔虫是一种微小的单细胞生物，通常直径不到一毫米，在海底的泥浆中茁壮成长，或与其他浮游生物一起漂浮在海面附近。[qh]
As they die, foraminifera are layered into the sediment that slowly accumulates on the sea floor,[qh]
当有孔虫死亡时，它们会被堆积在海底缓慢堆积的沉积物中，[qh]
so that by drilling down scientists are able to use the different isotopes contained in their shells to reconstruct not just ocean conditions, but changes in atmospheric carbon dioxide, ocean circulation and the extent and rate of change of the ice caps and plant life over the past 100m years or more.[qh]
因此，通过钻探，科学家们不仅可以利用它们外壳中含有的不同同位素来重现海洋环境，还可以重现大气二氧化碳的变化、海洋环流、冰盖和植物生命在过去1亿年或更长时间里的变化程度和速度。[qh]
