The complex pool of dissolved organic matter (DOM) in the oceans - one of the largest global reservoirs of carbon in the biosphere is almost exclusively accessible to marine microorganisms, the most abundant, diverse and productive organisms in marine food webs. Diverse members of the microbial community with different types of metabolisms interact with the broad spectrum of compounds present in the oceanic DOM pool and thereby, affecting the biogeochemical state of the ocean and thus the global climate. Knowledge on the interactions between individual constituents of the DOM pool and the microbial consortia is still in its infancy and needs to be refined to obtain a mechanistic understanding on the relation between the organic matter field and the metabolic network operated by the microbial community. Only when we arrive at this mechanistic understanding, we will be able to predict the response of the marine ecosystem to natural and anthropogenic perturbations.

The ultimate objective of our project is to understand the effect of jellyfish blooms, specifically in terms of organic matter released as jellyfish populations decay, on the natural microbial community and thus, on marine ecosystem functioning and biogeochemical cycles in the ocean. In particularly, we focus on the invasive bloom-forming ctenophore or American comb jellyfish, Mnemiopsis leidyi A. Agassiz, 1865. This species is still spreading with large and widespread impacts n ecosystems it invades. It feeds on fish stocks, can serve as vector for allochtnous (and even pathogenic) species and thus affect marine food web structure and function. Within this project, we see this species as a perturbation and the potential new, sporadically available, source of dissolved organic matter for the natural bacterial community of the invaded coastal marine ecosystem. We use an integrated interdisciplinary research – from the molecular to the ecosystem scale, from in-vito experiments to computer simulations.

The project comprises six interconnected packages:

1. Characterization of the microbially-mediated ctenophore organic matter degradation.
2. Characterization of the ctenophore organic matter degrading microbial community.
3. Determining the metabolic activity of ctenophore organic matter degrading microbial community
4. Characterization of key bacterial enzymes involved in the ctenophore Morganic matter degradation
5. Investigating the effect of different gelatinous zooplankton taxa on the ambient microbial community and on the surrounding ecosystem
6. Numerical and oceanographic modeling of microbially-mediated jellyfish detritus degradation

The resulting modelling system will form a solid base for further development into a prognostic system capable of forecasting the system response to anthropogenic and natural perturbations in the coastal marine ecosystems of the future.

The official webpage of the project

Partners

National Institute of Biology (NIB)

National Institute of Chemistry (KI)

Jozef Stefan Institute (JSI)

Microbial Oceanography research group, Department of Functional and Evolutionary Ecology, University of Vienna (MO/UNIVIE)

P-Lab team

Gregor Kosec

Filip Strniša

Funding

Publications