P. parvum cells contain chlorophylls
a and c as well as yellow-brown accessory
pigments and are capable of
photosynthesis. However, the organism
is thought to be a mixotroph that
can feed on bacteria and protists
(Skovgaard et al., 2003) and phagotrophy
has been observed in cultures. P.
parvum has a vitamin requirement in
laboratory culture (Droop, 1954).