Do the polyunsaturated aldehydes produced by Phaeocystis pouchetii (Hariot) Lagerheim influence diatom growth during the spring bloom in Northern Norway?

• Published in: Journal of Plankton Research
• Main Authors: Hansen, Espen, Eilertsen, Hans Chr.
• Format: Text
• Language: English
• Published: Oxford University Press 2006
• Subjects: Article; Norway; Antarc*; Antarctica; Northern Norway; Vestfjorden
• Online Access: http://plankt.oxfordjournals.org/cgi/content/short/fbl065v1; https://doi.org/10.1093/plankt/fbl065

The marine bloom-forming phytoplankter Phaeocystis pouchetii(Prymnesiophyceae) is known to produce and release the cytotoxic α,β,γ,δ-unsaturated aldehyde 2-trans-4-trans-decadienal (DD), known to inhibit mitotic cell divisions in several different cell types. The possible allelopathic effects of DD on monocultures of three common diatoms from the coastal waters of northern Norway were assessed. The results showed that division rates for all three diatom species (Skeletonema costatum, Chaetoceros socialis and Thalassiosira Antarctica) decreased as concentration of DD increased. Furthermore field data from the spring bloom in Vestfjorden (2000 and 2001) were analysed to examine whether the presence of P. pouchetii influences other species adversely. Our data revealed no significant adverse effect of P. pouchetii on diatom presence since diatom diversity generally was positively correlated to P. pouchetii biomass. The year with the lowest amounts of P. pouchetii had the lowest diversities, and the diatom species composition and abundance was comparable to situations where P. pouchetii was either absent or present in minute amounts. At some instances low diversity co-occurred with large fractions of P. pouchetii, but since this were at the strongest vertical mixing we believe this to be a result of physical control. P. pouchetii and S. costatum were the most frequently co-occurring species, and since they are both known producers of polyunsaturated aldehydes (PUA) we cannot exclude the possibility that the presence of DD released from P. pouchetii induced by heavy grazing might influence the growth of other phytoplankton species.