经济学人下载:尼莫的新角色 小丑鱼助力海葵呼吸

Science and technology
科学技术

Marine biology
海洋生物学

Finding Nemo's role
尼莫的新角色

Clownfish help their anemones breathe
小丑鱼助力海葵呼吸

IT IS one of the best-known relationships in nature: the anemone provides a tentacle-guarded home and the clownfish drives off predators that would chew its protector.
这是自然界中一个最广为人知的关系：海葵为小丑鱼提供触须拱卫的家园，小丑鱼则会驱赶会把海葵吃掉的掠食者。

Recent research has, however, shown there is much more going on.
然而最近的研究显示小丑鱼做的要比这多得多。

A study in 2009 revealed that waste excreted by clownfish provides vital nutrients to anemones.
2009年的一项研究显示，小丑鱼的排泄物是海葵极其重要的营养物。

Now researchers have found clownfish can boost their hosts' oxygen supplies at night too.
研究人员现在又发现小丑鱼还可以在夜间为其宿主增加供氧量。

Clownfish and anemones live on coral reefs where oxygen levels in the water often plunge at night as photosynthesis shuts down.
小丑鱼和海葵生活在珊瑚礁中，由于夜间不再有光合作用，海水在夜间的氧气含量常会骤然下降。

Some fish species are known to wave their fins over their coral homes to help keep the coral oxygenated.
人们已经知道有些鱼类会朝着它们的珊瑚家园摇摆鱼鳍来帮助珊瑚保持充氧状态。

Joseph Szczebak of Auburn University, in Alabama, and his colleagues wondered if clownfish might do something similar for anemones
美国阿拉巴马州奥本大学的约瑟夫?什切巴克及其同事想了解小丑鱼是否也会对海葵做出类似的行为。

It seems that they do. In a forthcoming edition of the Journal of Experimental Biology, Mr Szczebak and his colleagues report that they studied the oxygen consumption of clownfish and anemones in the laboratory, using special tanks which can measure oxygen levels in the water as it is pumped in and out of the tanks.
小丑鱼似乎这样做了。在即将出版的一期《实验生物学》上，什切巴克及其同事报道了它们在实验室中研究了小丑鱼和海葵的耗氧量。实验采用了特殊水箱，在水泵将水吸入，抽出水箱时可以测出水的含氧量。

Readings were taken for 20-minute periods during the night and day with just a fish in a tank, just an anemone or both in a tank together.
实验分别记录了在水箱中只有一条鱼，只有一棵海葵以及两者共存的三种情况下在夜间及日间中20分钟的含氧量读数。

Infra-red cameras quickly hinted that something was going on.
红外摄像机很快提供了事情发生的线索。

The fish became active at night when they had an anemone to hang out with.
当小丑鱼和海葵共处一箱时，它在夜间变得很活跃。

They would twirl around it, push its tentacles up and down, and whip their tails about.
小丑鱼会围着海葵转动，带着海葵的触须上下摆动，还让自己的尾部摇来摆去。

It was like a sort of dance.
这就像是一种舞蹈。

The combined level of oxygen consumption when the fish and anemone were together was significantly higher than when they were kept apart.
当小丑鱼和海葵共存时二者加在一起的耗氧量远高于比它们分开时的耗氧量之和。

Mr Szczebak speculates that the antics of clownfish allow more water to flow over the anemone, thus increasing the amount of oxygen the anemone can collect.
什切巴克推测，小丑鱼做出的滑稽动作可以使更多的水流过海葵，从而使海葵获取的氧量增加。

How lucky anemones are to have such good friends.
海葵有这么好的朋友真是三生有幸啊！