英语听力：自然百科 大堡礁 堡礁内外(3)（在线收听）

It's all exciting to see a large animal in the sea, and of course, the turtles are very iconic species in marine world.

能看到大型海洋动物总是令人很兴奋，不用说海龟是非常有代表性的海洋动物。

And I'm surrounded by them on this dive.

我现在被它们包围着。

Hundreds and hundreds of turtles are in the water column above me, passing over the reef's crest and now in the blue water.

成千上万的海龟正处于我上方的洋流中，它们随水流掠过礁顶，游进蔚蓝的海域中。

The turtles all converge on small islands made of coral rock and sand, known as the coral cases, but not all are suitable for nesting.

海龟都朝小岛汇聚，小岛是由珊瑚与石砂构成的，也叫珊瑚岩。但不是所有的礁石都适合筑巢。

Some only are sank down, exposed only at low water.

有些只是低潮时才露出的沙丘、

And many others have beaches that swamp to high tide.

许多有海滩的沙丘会在涨潮适变得泥泞不堪。