Most hydrogen and oxygen atoms in water are stable, but traces of both elements are also present as heavier isotopes.

在水中大多数氢原子和氧原子是稳定的，但这两个元素也有微量以较重的同位素形式存在。

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In layer upon layer of chemically distinctive water are traces of past atmospheres and ecosystems, forest fires and earthquakes and solar variation.

通过研究冰层之间化学性质各异的冰水，研究者们可以追溯古代大气、生态系统、森林大火、地震和日照的变化情况。

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Scientists from the University of Colorado at Boulder are unsure why the water vanished, but many suspect traces of the ocean remain in ice buried deep beneath the surface.

来自科罗拉多大学波德校区的科学家们不能确定海水消失的原因，但他们相信更多的有关海洋的猜想证据仍旧深埋于地表之下的冰中。

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Bobo Simbo stands thigh-high in a pool of orange water, sifting the mud for traces of gold dust.

VOA: standard.2010.04.22

In the lab, the fish raised in water with traces of the drug distanced themselves from other perch, became less fearful, and acted more adventurously, willing to leave safe refuges, the scientists said.

WSJ: Anxiety Drug in Rivers Affects Fish Behavior

It could identify soil types, verify the presence of water ice and dry ice at the poles, and even track traces of water underground.

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Remaining traces are indistinguishable in a body of water as enormous as the Gulf of Mexico and no different than the trace amounts that naturally seep from the ocean floor.

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