原文视听

As soon as it settles on the sea bed,
这艘沉船一落在海床上
the wreck comes under attack from invaders -
就遭遇入侵者的攻击
plankton, carried here by ocean currents.
那就是海流带来的浮游生物
These are the microscopic larvae of barnacles, sponges,
这些是藤壶，海绵动物
and, most importantly, corals.
以及最重要的珊瑚的细小幼虫
The larvae must attach themselves to the wreck.
珊瑚幼虫必须附着在沉船上
Once there, they can develop into young corals called polyps.
它们就定位后 发育成称为珊瑚虫的年轻珊瑚
But the polyps are very slow-growing,
但珊瑚虫成长速度极为缓慢
and there is lots of competition from other invaders.
并且面临其他入侵者的激烈竞争
Algae quickly cover the wreck,
海藻迅速覆盖沉船
and that's a problem for the young coral.
对年轻珊瑚造成问题
Algae attract grazers.
海藻会吸引食草动物
The polyps are in danger of being eaten
珊瑚虫在站稳脚步之前
before they've even got a proper foothold.
就可能被吃掉
If conditions are right, the survivors can go on to build a reef.
如果条件合适 幸存者就能继续建造珊瑚礁
Position is critical.
位置是关键因素
Too deep, and not enough light will reach the corals for them to grow.
太深的话 没有足够阳光让珊瑚成长
Too shallow, and they risk being exposed to the air at low tide.
太浅则可能在退潮时 暴露在空气中

重点解释

As soon as it settles on the sea bed,the wreck comes under attack from invaders -这艘沉船一落在海床上就遭遇入侵者的攻击

as soon as一 ... 就

I'll write you as soon as I get there.

我一到那儿，就给你写信。

Let us start as soon as he comes.

等他一来我们就动身。

The larvae must attach themselves to the wreck.珊瑚幼虫必须附着在沉船上

attach to附在 ... 上； 系在 ... 上

I'll attach my comments to this page.

我将把我的评语附在这页上。

He'll attach the label to your luggage.

他会把标签系在你的行李上。

Once there, they can develop into young corals called polyps.它们就定位后发育成称为珊瑚虫的年轻珊瑚

develop into发展成为

The small port has developed into a big city.

该小港市已发展成为一个大城市。

Their friendship soon deepened into love.

他们的友谊很快发展成为爱情。

The polyps are in danger of being eaten before they've even got a proper foothold.珊瑚虫在站稳脚步之前就可能被吃掉

in danger of有 ... 的危险

He was in danger of losing his life.

他有失去生命的危险。

The house is now in danger of collapse.

这座房子