Science / Marine Biology / Plankton: Pelagic organisms that float through the water column, not attached to any substrate and unable to move against the currents and tides. Plankton can be further divided into phytoplankton and zooplankton, meroplankton and holoplankton. Compare nekton.
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Science / Marine Biology / Mixoplankton: Planktonic organisms that can be classified at several trophic levels. For example, some ciliates can be photosynthetic but also can ingest other plankton and are heterotrophic. MORE
Science / Marine Biology / Ultraplankton: Planktonic organisms that are less than 2 micrometers in size MORE
Science / Marine Biology / Megaplankton: Planktonic organisms that are greater than or equal to 2000 micrometers in size MORE
Science / Marine Biology / Nanoplankton: Planktonic organisms that are 2-20 micometers in size. MORE
Science / Marine Biology / Macroplankton: Planktonic organisms that are 200-2,000 micrometers in size. MORE
Science / Marine Biology / Holoplankton: Organisms spending all their life in the water column and not on or in the sea bed MORE