Karenia mikimotoi

has been described in detail by Thingstad and Billen (1994) and by Alderkamp et al.
(2007).
Although producing nuisance blooms resulting in anoxia and fish kills (see Landsberg,
2002), Phaeocystis has historically not been regarded as toxic until quite recently.
Smayda (2006) briefly reviewed the literature and concluded
“Notwithstanding the diverse nuisance and toxic impacts reported for Phaeocystis, its
blooms are usually without the apparent negative impacts, particularly fish kills,
reported for the related haptophyte species C. polylepis and P. parvum f. parvum and f.
patelliferum.”
As noted in Hansen et al. (2003) the International Oceanographic Commission has
placed P. globosa and P. pouchetii on its list of harmful algae (see
http://www.bi.ku.dk/ioc/) and the entry states: “P. globosa was reported to form
toxins in China (Qi et al., 2002). However, the short abstract published only mentions
that hemolysin(s) was formed”, but these records are now several years old.
A more recent review by Verity et al. (2007) discusses the toxic properties of
Phaeocystis spp. in the context of allelopathy. Those properties, taken from the
literature cited, are summarised in Table 3. The concept of allelopathy in phytoplankton
- the production of compounds by an alga that inhibit the growth of competing algae - is
discussed by Legrand et al. (2003). It goes some way to explaining the reasons for the
toxic characteristics of many algae.
6 A Literature review of the potential health effects of marine microalgae and macroalgae