How they eat
Microscopic viruses are the most abundant biological agents in Antarctic waters, with numbers up to 4 million per millilitre. They inject their DNA or RNA and take over the cell metabolism of the host resulting in viral multiplication and eventual cell rupture. In temperate marine food webs, viruses have been shown to be major agents of death for bacteria and phytoplankton.
Protozoa feed by puncturing, engulfing or ingesting.
- Puncturing — many dinoflagellates and ciliates pierce the prey cell with a peduncle, digesting and absorbing its contents.
- Engulfing — they cover prey cells with their cytoplasm and digest them. This is the prime strategy for amoeboid cells. Some other cells, notably dinoflagellates, can project a veil of cytoplasm (pallium) externally through their cell wall to enclose prey. They can sometimes successfully engulf cells larger than themselves.
- Ingesting — feeding currents created by cilia or flagella draw prey cells to the predator where they are captured and ingested.