plankton

The first organisms that reproduced sexually were free-floating plankton.

最早的有性繁殖生物是自由漂浮的浮游生物。

This book has large color photographs of sea animals, from plankton to clownfish to orcas.

这本书有许多海洋动物的彩色照片，从浮游生物到小丑鱼乃至逆戟鲸。

This change in plankton found in marine deposits is what marks the boundary between the Cretaceous and the Tertiary.

海洋沉积物中浮游生物的这种变化标志着白垩纪和第三纪的分界线。

There may be giant plankton on gaseous planets. They float in a thick atmosphere like small spaceships and live by "eating" lightning.

气态星球上可能存在巨型浮游生物。它们像小型飞船那样漂在厚厚的大气中，靠“吃”闪电获取能量为生。

Plankton generally thrive in areas of the ocean with sufficient concentrations of certain nitrogen compounds near the surface, where plankton live.

浮游生物通常在海洋表面附近某些含氮化合物浓度足够高的区域大量繁殖，而海洋表面正是浮游生物生存的地方。