沿海水域通常有更多的悬浮物质，原因为河流的输入，水底翻起的物质，浮游生物的增加。

Coastal waters generally have more suspended material due to river input, material stirred up from the bottom, and increased plankton.

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Mila不知道这种生物的名字因为她关于水底王国的知识很稀少。

Mila has no known name for this creature as her knowledge of the underwater kingdoms is sparse.

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当这些生物死后，它们的外壳便会沉入水底并逐渐堆积成厚厚的石灰岩层，这就是为什么在石灰岩中经常可发现一些生物化石的原因。

When these creatures died, their shells fell to the bottom and gradually built up thick layers of limestone. For this reason, fossils are commonly found in much limestone.

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