This density difference is an index of ocean stratification .

这种水密度差就是海洋分层的标志。

Stratification threatens this recycling system by suppressing the vertical movement of water .

而海水分层会抵制水的垂直流动，从而威胁着这种再循环系统。

And the beaufort sea 's stratification is high in both summer and winter .

波弗特海在夏冬两季的分层都很活跃。

The objects of social adaptation are broken down in the stratification of collective education .

在集体教育的层面上来分解社会适应的目标。

There began to be considerable social stratification within this people .

而这个民族开始形成一个重要的社会阶层。