However, phytoplankton flourish only in surface waters where iron levels are sufficiently high.

然而，浮游植物只在铁含量足够高的地表水中繁殖。

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Deserts contain large amounts of groundwater when compared to the amounts they hold in surface stores such as lakes and rivers.

与湖泊、河流等地表储存的地下水相比，沙漠中含有大量的地下水。

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Also, in surface water, there is a weak acid, carbonic acid, not sulfuric acid, but carbonic acid that helps dissolve the rock.

另外，在地表水中存在一种弱酸，它是碳酸，而不是硫酸，而且是能帮助溶解岩石的碳酸。

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They are small-scale workers, digging in surface pits which have already been mined.

VOA: standard.2010.04.22

It will surface back up in another piece of work or another idea at some point in your life.

在某个时刻，旧点子会以另一种形式重新出现,或者另一个想法在会出现在你的生活中。

斯坦福公开课 - Twitter之父Jack.Dorsey演讲：好奇和灵感的力量课程节选

That is the lowest point on the earth's land surface so this dramatic drop in just a very short geographical area.

这是地球陆地表面的最低点,这急剧下降是在很短的地理范围内。

耶鲁公开课 - 旧约导论课程节选

Recent rises in surface temperature have been pinned on rising levels of greenhouse gases, particularly carbon dioxide.

ECONOMIST: Climate change (I)

This is because the atmosphere does not have an iron grip on the carbon-dioxide level in surface waters.

ECONOMIST: Ocean acidification

The industry's now down to fewer than 2000 directly-employed workers in surface mining.

BBC: Red ink and black stuff