Eukaryotic pathogens (Chytridiomycota and Oomycota) infecting marine microphytobenthic diatoms – a methodological comparison |
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| Authors: | Bettina Scholz Frithjof C Küpper Wim Vyverman Ulf Karsten |
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| Institution: | 1. Institute of Chemistry and Biology of the Marine Environment, University of Oldenburg, , Wilhelmshaven, 26382 Germany;2. Oceanlab, University of Aberdeen, , Newburgh, AB41 6AA UK;3. Department of Biology, Section of Protistology and Aquatic Ecology, University of Ghent, , Ghent, 9000 Belgium;4. Institute of Biological Sciences, Applied Ecology & Phycology, University of Rostock, , Rostock, 18059 Germany |
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| Abstract: | Using sediment samples from the Solthörn tidal flat (southern North Sea, Germany), collected in bi‐weekly intervals from June to July 2012, a range of qualitative and quantitative screening methods for oomycete and chytrid pathogens infecting benthic diatoms were evaluated. Pre‐treatment of sediment samples using short ultrasound pulses and gradient centrifugation, in combination with CalcoFluor White, showed the best results in the visualization of both pathogen groups. The highest number of infected benthic diatoms was observed in mid July (5.8% of the total benthic diatom community). Most infections were caused by chytrids and, in a few cases, oomycetes (Lagenisma Drebes (host: Coscinodiscus radiatus Ehrenberg) and Ectrogella Zopf (hosts: Dimeregramma minor in Pritchard and Gyrosigma peisonis). Among the chytrids, sporangium morphology indicated the presence of five different morphotypes, infecting mainly epipelic taxa of the orders Naviculales (e.g., Navicula digitoradiata) and Achnanthales (e.g., Achnanthes brevipes Agardh). The presence of multiple pathogens in several epipelic diatom taxa suggests a significant role for fungal parasitism in affecting microphytobenthic diatom succession. |
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| Keywords: | benthic diatoms CalcoFluor White chytrids fluorescein isothiocyanate‐labeled wheat‐germ agglutinin oomycetes sporangia staining methods |
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