【经济学人】海洋酸化的影响|2016.12.03|总第751期

Tough but vulnerable

海水酸化使海胆“外强中干”

GLOBAL warming is not the only environmental change that is being wrought by rising emissions of carbon dioxide. This gas, acidic when dissolved in water, is also lowering the pH of the world’s sea water—a phenomenon known as ocean acidification.

全球变暖是二氧化碳排放量的增加所带来的众多环境变化之一。二氧化碳溶于水之后会酸化中性的水，降低海水pH值——这就是“海水酸化” 现象。

• acidification [ə,sɪdɪfɪ'keɪʃən]：n，酸化，变酸

How much to worry about this acidification (or, strictly, reduction in alkalinity, for there is no risk of the sea actually becoming acidic) is a matter of debate. The threat most talked of is to creatures that make shells out of calcium carbonate. As school chemistry experiments with chalk and vinegar demonstrate, calcium carbonate dissolves in acid, so an ocean less alkaline than it used to be might make life harder for shell-forming animals. Numerous laboratory experiments agree. There is also evidence that the shells of several widespread marine species are thinner and weaker now than they were a few decades ago. What there has not been, though, is a controlled study in the wild—at least, not until now.

海水酸化（严格来说，这只是一种海水碱度降低的现象，事实上海水酸化是没有什么风险的。）是一个争议性话题，对于该现象带来的环境威胁的讨论最多的就是其对贝类生物（它们的壳体是碳酸钙质）的影响。这就好比在课堂上做的粉笔和醋的化学实验原理一致——碳酸钙可被酸剂溶解，所以海水的碱度降低会使得贝类生物的生存变得更加艰难。该观点在此前的很多实验中都得到证实。（期待您的翻译，明天会有针对这句话的读者试译详解哟~）

• alkalinity [,ælkə'lɪnətɪ] ：n,碱度

The gap has been plugged by Miles Lamare of the University of Otago, in New Zealand, and his colleagues, who have just published their study in the Proceedings of the Royal Society. Dr Lamare observed that there are several places in the sea where acidification is happening naturally, because low-level volcanic activity is releasing carbon dioxide from submarine vents. Two such vents are located off the coast of Papua New Guinea. These, he thought, would be a good place for an experiment.

值得庆幸的是，该研究空白现今已得到填补。新西兰奥塔哥大学的Miles Lamare教授以及他的同事已经将他们的研究成果发表在《皇家学会会议录》一文上。Lamare博士发现一些地方海水的酸化现象是由于海底低级火山喷发而释放出二氧化碳造成的自然酸化。典型代表如位于巴布亚新几内亚海岸火山口。Lamare博士认为这两个地方很有实验价值。

• submarine ['sʌbməriːn]：adj,海底的

Marine biologists suspect that the threat of acidification is most serious to an animal when it is a small, planktonic larva. Dr Lamare and his colleagues therefore carried out their experiment on the larvae of Echinometra, a type of sea urchin. They hung cages containing these larvae, newly hatched from freshly collected adult urchins, in the water above the vents, and also in nearby water of normal pH, to act as a control. They then left the cages for a day or two, to let the larvae grow, before examining their changes under the microscope.

海洋生物学家同时怀疑海水酸化对小型浮游幼虫的影响也很大。因此，Lamare博士以及他的团队对一种海生海胆——长海胆（Echinometra）的幼虫进行了实验。他们收集了新鲜的成年海胆，将它们刚刚孵化出的幼虫放置在笼子中，并悬置在火山口之上的海水里，此外，他们在正常PH值的海水里放置了同样的装置作为实验的控制因素。科学家们将笼子放置在海水中一到两天以便幼虫体生长，接下来就是在显微镜下观察它们的变化。

• larvae ['lɑrvi]：n,幼体，幼虫

• urchin ['ɜːtʃɪn]：n,海胆

• Echinometra：n,长海胆

At the first vent site, the differences were startling. In this case all of the larvae came from adults collected in the control area, ie, living in water of normal pH. Those raised in the cages over the vent grew much more slowly than those in the control area. They were also more prone to develop asymmetrically.

在第一个火山口的位置，其差异十分惊人。在该次实验中，实验对象幼虫产自来源于控制区即正常PH值海水中的成虫。它们的生长速度与控制区域中的幼虫相比慢了很多，并且更趋向于发育成不对称形态。

• prone [prəʊn]：adj,有倾向性的，易于…的

• asymmetrically [əsi'metrikli]：adv,不对称地

At the second site, the picture was more complicated. In this case Dr Lamare carried out a more sophisticated experiment on larvae collected from adults that dwelled in the vents as well as from the control area. It tested both sorts of larvae in both locations, to see if the young of adults that had been living in the vent were inured to less alkaline water. Surprisingly, in light of the earlier result, pH made no difference to the growth rates of either sort of larva, though it still affected rates of asymmetry.

在第二个火山口的位置的实验过程更加复杂。Lamare博士收集了生活在正常海水（控制区域）中火山口附近的成虫孵化的幼虫。实验测试并对比生活在不同地方的两种幼虫，观察成长于火山口附近的幼虫是否能够较普通幼虫更适应低碱度的海水。令人惊讶的是，尽管PH值改变影响了幼虫的不对称形态，但两种幼虫的生长速率没有明显的差异。

• sophisticated [sə'fɪstɪkeɪtɪd]：adj,复杂的

And that was not the only surprise. Dr Lamare also found that larvae whose parents had come from the vent grew larger than those whose parents had not, regardless of the site where they were raised. That does hint at genetic differences between vent-dwelling and non-vent-dwelling Echinometra—just not the one, namely acid resistance, that might have been expected.

这并不是唯一惊人的地方。Lamare博士发现，在不考虑生长环境的条件下，来源于火山口的成虫幼体比普通的成虫幼体形态上更大一些。这同样暗示火山口的和非火山口环境的长海胆，其基因上或许有所差别---和之前的预期的一样，生活条件不同的两种海胆不仅仅只是在抗酸性上不同。

As these somewhat confusing results show, a single experiment like this can yield only limited information. But what really counts is that scientists have now discovered an important natural laboratory in which to investigate the effects of ocean acidification further and, hopefully, find more definitive answers about what many see as a worrying problem.

这些意义不明的结果只能证明，单一的实验结果所得到信息非常有限。而该实验真正的价值点在于现今科学家已经开发出了重要的自然实验环境，并可以进一步研究海洋酸化的深远影响，届时希望可以对上述仍然困挠我们的问题寻找出准确的解答。

翻译 ▍zoey

审核 ▍阳光下的冰叶

编辑 ▍毛毛

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