Fungal infections of the phytoplankton: Seasonality, minimal host density, and specificity in a mesotrophic lake

  • Holfeld H
  • 41


    Mendeley users who have this article in their library.
  • 52


    Citations of this article.


Phytoplankton infections by fungal parasites in the upper, mixed layer of a mesotrophic northern temperate lake were analysed according to the following parameters: host and parasite species, host population density and prevalence of infection, resting spore formation by the parasite, and the lowest host density at which parasites appeared. The phytoplankton taxa recorded included the Cyanobacteria, Dinomastigota, Chrysophyceae, Bacillariophyceae, Chlorophyceae, Cryptophyceae and Haptophyceae, but infection was never found in the last two classes. The parasites belonged almost exclusively to the monocentric Chytridiomycetes. Fungal epidemics occurred at all times of the year. Parasites appeared at population densities as low as about 1 cell ml22121 in some host species, with infection prevalence sometimes exceeding 80%. The proportion of the total phytoplankton biovolume infected by fungi was usually much <1%, but occasionally reached 10%. Parasitism proved to be highly species-specific, with one parasite species usually infecting only one host species. In the case of Zygorhizidium planktonicum, which infected both Asterionella formosa and Synedra acus, there is evidence that two species-specific formae speciales, each infecting only one of these two host species, are present in the lake.

Author-supplied keywords

  • Chytridiales
  • Epidemics
  • Fungi
  • Parasitism
  • Phytoplankton

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document


  • Harald Holfeld

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free