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Abstract

Jellyfish blooms have increased worldwide, and the outbreaks of
jellyfish population not only affect the food web structures via
voracious predation but also play an important role in the dynamics of
nutrients and oxygen in planktonic food webs. However, it remains
unclear whether specific carbon compounds released through jellyfish
metabolic processes have the potential to shape bacterial community
composition. Therefore, in this study, we aimed to investigate the
compositional succession of the bacterioplankton community in response
to the dissolved organic matter (DOM) released by the live Scyphomedusae
Cyanea lamatrkii and Chlysaora hysoscella collected from Helgoland Roads
of the North Sea. The bacterial community was significantly stimulated
by the DOM released form live jellyfish and different dominant phylovpes
were observed for these two Scyphomedusae species. Furthermore, the
bacterial community structures in the different DOM sources,
jellyfish-incubated media, Kabeltonne seawater, and artificial seawater
(DOM-free) were significantly different, as revealed by automated
ribosomal intergenic spacer analysis fingerprints. Catalyzed reporter
deposition fluorescence in situ hybridization (CARD-FISH) revealed a
rapid species-specific shift in bacterial community composition.
Gammaproteobacteria dominated the community instead of the Bacteroidetes
community for C. lcrmarrkii, whereas Gammaproteobacteria and
Bacteroidetes dominated the community for C. hysoscella. The significant
differences in the bacterial community composition and succession
indicate that the components of the DOM released by jellyfish might
differ with jellyfish species.