plank·ton /ˈplæŋ(k)tən, ˌtɑn/
  浮游生物
  Plank·ton n.  Biol. All the animals and plants, taken collectively, which live at or near the surface of salt or fresh waters. -- Plank*ton*ic a.
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  plankton
       n : the aggregate of small plant and animal organisms that float
           or drift in great numbers in fresh or salt water