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　　标题：铁和全球变暖 (19)

　　提出一个理论：某科学家提出假设，往海面投铁粉能降低空气中二氧化碳含量。因为研究表明，海面上凡是藻类少的区域，都缺少铁。投铁粉/铁离子以后，海洋的营养(nutrient)上升，从而导致藻类(alage)大面积繁衍，被滋养的绿藻浮到海洋表面，通过光和作用大量吸收大气中的二氧化碳，从而达到缓解全球变暖的趋势。

　　提出证据，支持该理论：南极的某地质研究表明，在地球上一个冰河时期(ice age)空气中二氧化碳明显减少，是因为在那个时候地球又冷又干燥，很多灰尘到处飘，于是大量地面上含铁的灰尘飘到了海面上，所以那时CO2 含量少。所以就能证明假设成立。

　　问题：

　　Q1：有两个细节题，请务必要搞清楚nutrient，alage，iron 间的关系。(细节题)

　　(有一个细节题是nutrient，alage，iron 这三个间有个逻辑关系链的。)

　　Q2：下面哪个是削弱(weaken)这个理论(theory)的现象。

　　Q3：(忘了)

　　答案：可以推断出上一次冰河时期比较干燥。

　　理由：文章中说那时很干燥。

　　英文背景知识：

　　Seeding the oceans with iron is a viable way to permanently lock carbon away from the atmosphere and potentially tackle climate change, according to scientists who have studied how the process works naturally in the ocean.

　　Ocean geo-engineering using iron as a fertiliser for microscopic creatures in the ocean is seen as a possible way to slow down global warming. Marine algae and other phytoplankton capture vast quantities of carbon dioxide from the atmosphere as they grow, but this growth is often limited by a lack of essential nutrients such as iron. Artificially adding these nutrients would make algae bloom and, as the organisms grow, they take up CO2. When they die, some of the

　　organisms sink to the bottom of the ocean, taking their carbon with them. But there has been little scientific work previously on whether the CO2 stays locked up for a significant period of time.

　　Understanding how much iron is needed, how it should be added and what effect it would have on the local ecology is crucial in assessing whether iron fertilisation would be a useful tool in reducing carbon dioxide in the atmosphere.

　　In the latest research, published tomorrow in Nature, the Southampton scientists studied a natural source of iron into the sea near the Crozet Islands at the northern boundary of the Southern Ocean, 1,400 miles south-east of South Africa. Their work showed that iron – which is added by the volcanic rocks to the north but not to the south of the island – successfully tripled the growth of phytoplankton(浮游藻) and also the amount that sank to the bottom of the sea.

　　Peter Burkill, said: "This is a significant result. It suggests that ocean iron fertilisation might work for reducing atmospheric CO2 through export of carbon into the ocean's interior. But the next step from natural experiments, such as this one, to artificial ones is crucial. We now need to know what the ecological impacts of artificial fertilisation experiments are."

　　中文背景知识：铁粉·海洋·浮游植物·全球变暖

　　科学家们相信，铁可以充当“肥料”，刺激浮游生物生长，吸收周围海水中的二氧化碳

　　据2007 年9 月英国《星期日泰晤士报》报导，科学家们正考虑一项对付气候变暖的计划──向海洋里倾倒数百万吨铁粉，以改变海水的化学成分。科学家们相信，铁可以充当“肥料”，刺激浮游生物生长，吸收周围海水中的二氧化碳。浮游生物死后会沉到海底，将碳元素永久锁在海底。

　　去年早些时候，美国“浮游生物”公司在太平洋卸下100 吨铁粉，成功令浮游生物大量繁殖。“浮游生物”公司首席执行官拉斯·乔治说，增加1 吨铁粉就可以消除海洋中多达10 万吨溶解的二氧化碳。

　　伍兹霍尔海洋学研究所的科学家肯·比塞勒说，研究人员进行了十几项科学试验，有的得出了有意义的结论。两年前，他带队在太平洋卸下铁粉，并研究了对浮游生物的影响。

　　比塞勒发现铁粉的确引起了浮游生物激增，但最后锁在海底的碳元素数量差异很大。在一个海域，约一半的浮游生物死后沉到弱光层，将碳元素锁在海底;但在另一个海域，将碳元素带到海底的浮游生物只有百分之几。比塞勒说：“海洋肥化需要进一步研究，但是如果我们有机会减少大气中的碳含量，我们必须认真研究。”

　　不过对于此项计划，也尚有另一方面值得研究的，那就是人为地大规模改变海洋中的原有生态，是否又会导致一场生态灾难，而被证明为是人类的一次自作聪明? 所以保守的环保主义者，还是需要坚持从自己做起，倡导并践行对环境友好的生产发展模式和生活方式。