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The potential of zooplankton in constraining chytrid epidemics in phytoplankton hosts
- Source :
- Ecology, 101(1):e02900. John Wiley and Sons Ltd, Ecology
- Publication Year :
- 2020
-
Abstract
- Fungal diseases threaten natural and man‐made ecosystems. Chytridiomycota (chytrids) infect a wide host range, including phytoplankton species that form the basis of aquatic food webs and produce roughly half of Earth's oxygen. However, blooms of large or toxic phytoplankton form trophic bottlenecks, as they are inedible to zooplankton. Chytrids infecting inedible phytoplankton provide a trophic link to zooplankton by producing edible zoospores of high nutritional quality. By grazing chytrid zoospores, zooplankton may induce a trophic cascade, as a decreased zoospore density will reduce new infections. Conversely, fewer infections will not produce enough zoospores to sustain long‐term zooplankton growth and reproduction. This intricate balance between zoospore density necessary for zooplankton energetic demands (growth/survival), and the loss in new infections (and thus new zoospores) because of grazing was tested empirically. To this end, we exposed a cyanobacterial host (Planktothrix rubescens) infected by a chytrid (Rizophydium megarrhizum) to a grazer density gradient (the rotifer Keratella cf. cochlearis). Rotifers survived and reproduced on a zoospore diet, but the Keratella population growth was limited by the amount of zoospores provided by chytrid infections, resulting in a situation where zooplankton survived but were restricted in their ability to control disease in the cyanobacterial host. We subsequently developed and parameterized a dynamical food‐chain model using an allometric relationship for clearance rate to assess theoretically the potential of different‐sized zooplankton groups to restrict disease in phytoplankton hosts. Our model suggests that smaller‐sized zooplankton may have a high potential to reduce chytrid infections on inedible phytoplankton. Together, our results point out the complexity of three‐way interactions between hosts, parasites, and grazers and highlight that trophic cascades are not always sustainable and may depend on the grazer's energetic demand.
- Subjects :
- 0106 biological sciences
Food Chain
Zoospore
Cyanobacteria
010603 evolutionary biology
01 natural sciences
Zooplankton
Article
allometric relationship
food-chain model
Phytoplankton
Animals
Ecosystem
Epidemics
Trophic cascade
Ecology, Evolution, Behavior and Systematics
Trophic level
Chytridiomycota
food‐chain model
Planktothrix
biology
Plan_S-Compliant-TA
Ecology
010604 marine biology & hydrobiology
fungi
Articles
biology.organism_classification
rotifer
trophic cascade
Density dependence
density dependence
international
Subjects
Details
- Language :
- English
- ISSN :
- 00129658
- Database :
- OpenAIRE
- Journal :
- Ecology, 101(1):e02900. John Wiley and Sons Ltd, Ecology
- Accession number :
- edsair.doi.dedup.....b04c376a9d077271d9ef7c2001333aab