Chemical cues induce consumer-specific defenses in a bloom-forming marine phytoplankton.

Blooms of the phytoplankton Phaeocystis can comprise 85% of total production and generate major biogeochemical signals across broad oceanic regions. The success of Phaeocystis may result from its ability to change size by many orders of magnitude when it shifts from small cells of 4-6 microm to large colonies of up to 30,000 microm in diameter. Single cells are consumed by ciliates but not copepods, whereas colonies are consumed by copepods but not ciliates.

Ecology of the red-tide dinoflagellate Ceratium furca: distribution, mixotrophy, and grazing impact on ciliate populations of Chesapeake Bay.

Ceratium furca is a primarily photosynthetic dinoflagellate also capable of ingesting other protists. During 1995 and 1996, we documented the abundance of C. furca in Chesapeake Bay and determined grazing rates on prey labeled with fluorescent microspheres.