The ice layer sealing off many of these lakes, is up to 15 feet thick.

冰层封锁许多这样的湖泊，冰层厚达15英尺。

It's just like a whole bunch of icing layers on a cake.

这就像许多层糖霜加在了一个蛋糕上。

So, over the past 40 or 50 years, the number of ice layers that have formed each summer has been increasing.

因此，在过去的 40 或 50 年里，每年夏天形成的冰层数量一直在增加。

And then right what we're standing on, where this probe stops - it's a bit covered with snow now, but there's an ice layer right there.

然后就在我们所站的地方，这个探测器停止的地方——现在有点被雪覆盖，但那里有一层冰。