Scientific Article
previous document  unige:27425  next document
add to browser collection
Title

The parasitic chytrid, Zygorhizidium, facilitates the growth of the cladoceran zooplankter, Daphnia, in cultures of the inedible alga, Asterionella

Authors
Kagami, Maiko
von Elert, Eric
de Bruin, Arnout
Van Donk, Ellen
Published in Proceedings of the Royal Society. B, Biological Sciences. 2007, vol. 274, no. 1617, p. 1561-1566
Abstract In food-web studies, parasites are often ignored owing to their insignificant biomass. We provide evidence that parasites may affect trophic transfer in aquatic food webs. Many phytoplankton species are susceptible to parasitic fungi (chytrids). Chytrid infections of diatoms in lakes may reach epidemic proportions during diatom spring blooms, so that numerous free-swimming fungal zoospores (2-3 mu m in diameter) are produced. Analysis shows that these zoospores are rich in polyunsaturated fatty acids and sterols (particularly cholesterol), which indicates that they provide excellent food for zooplankters such as Daphnia. In life-table experiments using the large diatom Asterionella formosa as food, Daphnia growth increased significantly in treatments where a parasite was present. By grazing on the zoospores, Daphnia acquired important supplementary nutrients and were able to grow. When large inedible algae are infected by parasites, nutrients within the algal cells are consumed by these chytrids, some of which, in turn, are grazed by Daphnia. Thus, chytrids transfer energy and nutrients from their hosts to zooplankton. This study suggests that parasitic fungi alter trophic relationships in freshwater ecosystems and may be the important components in shaping the community and the food-web dynamics of lakes.
Identifiers
Full text
Citation
(ISO format)
KAGAMI, Maiko et al. The parasitic chytrid, Zygorhizidium, facilitates the growth of the cladoceran zooplankter, Daphnia, in cultures of the inedible alga, Asterionella. In: Proceedings of the Royal Society. B, Biological Sciences, 2007, vol. 274, n° 1617, p. 1561-1566. https://archive-ouverte.unige.ch/unige:27425

167 hits

0 download

Update

Deposited on : 2013-04-09

Export document
Format :
Citation style :