出现内波是因为海洋是分层的，深层水更凉，密度高而且含盐量高，浅层水更暖和，密度小而且更淡。

Internal waves happen because the ocean is layered. Deep water is cold, dense, and salty, while shallower water is warmer, lighter, and fresher.

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来自海洋板块中碳元素混杂在如此之深的地幔中这一现象的发现使人们产生更大的疑问，到底有多少海洋板块和沉积物被带到深层地幔中。

The discovery that carbon from the ocean floor can be mixed so deep within the mantle raises the larger question of how much of the ocean floor and sediments are carried to the deep mantle.

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许多发现都是来自于过去二十年对于从深层海洋底钻出的矿物样本的研究。

Many of the findings come from studies of core samples drilled from the deep seafloor over the past two decades.

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