Combined effect of warming and infection by Labyrinthula sp. on the Mediterranean seagrass Cymodocea nodosa

Ylva S. Olsen*, Carlos M. Duarte

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Global warming is predicted to alter host-pathogen relationships and increase disease outbreaks in terrestrial and marine environments. We evaluated the effect of warming on the susceptibility of Cymodocea nodosa to infection by Labyrinthula sp. (the causative agent of seagrass wasting disease) by monitoring disease symptoms and seagrass photobiology. Seagrass shoots were incubated at temperatures between 24 and 32°C, encompassing maximum summer seawater temperatures projected for the Mediterranean during the 21st century, and exposed to Labyrinthula sp. for 2 wk. The effect of temperature on pathogen growth was also tested by growing Labyrinthula sp. in liquid medium for 24 h. Disease severity, measured as lesion size, decreased with warming, but the presence of lesions had a negative effect on quantum yield, quantum efficiency, optimum irradiance and the maximum electron transport rate (ETRmax) in adjacent tissue across the full range of temperatures. The direct effect of increased temperature on photochemical efficiency was positive in terms of quantum yield, whereas compensation and optimum irradiances and ETRmax decreased slightly with warming. Warming stimulated Labyrinthula sp. growth up to a threshold of around 26 to 28°C, beyond which cell division and elongation of the ectoplasmic network decreased. At 32°C almost no growth was observed. Our results indicate that warming does not make C. nodosa more susceptible to infection by Labyrinthula sp. and that the disease is unlikely to pose a serious threat to C. nodosa, but that the pathogen is able to persist during forecasted warm periods.

Original languageEnglish (US)
Pages (from-to)101-109
Number of pages9
StatePublished - Jul 21 2015

Bibliographical note

Publisher Copyright:
© 2015 Inter-Research.


  • Climate change
  • Host
  • Pathogen
  • Photosynthetic performance
  • Seagrass
  • Temperature
  • Wasting disease

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology


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