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).