Untersuchung der Beziehung zwischen dem Zooplankton Mikrobiom und globalen biogeochemischen Kreisläufen
Zusammenfassung der Projektergebnisse
The aim of this project was to assess the importance of zooplankton in dissolved organic matter (DOM) and nutrient cycling through prokaryotic activity. Little is known about the molecular composition of zooplankton-derived DOM and its bioavailability to microbial degradation. Therefore, to better understand the relation between zooplankton DOM and microbes, we conducted a manipulation experiment where DOM generated by a mixed zooplankton community feeding on phytoplankton was used as a substrate for a prokaryotic community, and the DOM molecular composition was characterized and monitored by Fourier-transform ion cyclotron resonance mass spectrometry over time. Here we showed that zooplankton activity promotes the transformation of POM to DOM and that the freshly released zooplankton-derived DOM is a source of labile dissolved organic carbon and nitrogen that is preferentially taken up by the marine microbial community. The marine microbes quickly transformed the zooplankton-derived DOM, assimilating it into biomass. Additionally, microbial remineralization changed the zooplankton-derived DOM molecular composition mainly by removing nitrogen-containing molecules and unsaturated compounds. The changes in the DOM molecular composition over time resulted in the decreased bioavailability of the organic matter pool. Consequently, at the end of the incubation, the zooplankton-derived DOM molecular composition became closer to that of the environmental DOM. Our findings show that part of the carbon derived from zooplankton activity bypasses secondary consumers and is instead shunted directly to the microbial loop, similarly to the viral shunt. Finally, the results obtained from the project suggest that zooplankton-microbial interactions play an essential role in the ocean’s biogeochemical cycles through regulating carbon and nutrient fluxes.
Projektbezogene Publikationen (Auswahl)
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Zooplankton‐derived dissolved organic matter composition and its bioavailability to natural prokaryotic communities. Limnology and Oceanography, 68(2), 336-347.
De Corte, Daniele; Varela, Marta M.; Louro, Angeles M.; Bercovici, Sarah K.; Valencia‐Vila, Joaquín; Sintes, Eva; Baltar, Federico; Rodríguez‐Ramos, Tamara; Simon, Meinhard; Bode, Antonio; Dittmar, Thorsten & Niggemann, Jutta
