Ongoing projects

Elucidating microbial dynamics on marine aggregates

Marine aggregates and particles are hotspots of microbial activity and are colonized by a variety of microorganisms. However, little is known about the microbial processes on naturally occurring marine aggregates as they descent into the ocean interior. This project is focusing on microbial degradation processes that occur on colonization and degradation patterns of marine aggregates from the surface to the deep ocean.

This project is funded by the Austrian Science Fund (M-2797)
PI: me.

Extracellular vesicles (EVs) in the ocean

In all three domains of life cell growth is associated with the production of EVs, which mediate diverse network of intercellular interactions and functions. 
This project aims to expand our understanding of vesicle production by marine bacteria, and answer fundamental questions, such as, what factors influence production of vesicles in the marine bacteria? And do these factors affect also the type of the produced vesicles.

PI: me.

The effect of jellyfish blooms on natural bacterioplankton communities
The ultimate objective of this 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.

This is a joint Slovenian-Austrian research project.
PIs:  Dr. Tinkara Tinta and Prof. Gerhard J Herndl

Previous projects

PhD | Ecological observations of pelagic bacterial and archaeal communities in the Atlantic-Arctic boundary zone

My PhD was conducted in the framework of the FRontiers in Arctic marine Monitoring (FRAM) project, which monitors the impact of changing ocean properties and sea ice conditions on the Arctic marine ecosystem. The main objective of my research was to investigate the ecology and the composition of pelagic microbial communities in the Fram Strait, the main gateway between the Arctic and the Atlantic Oceans. The results of my PhD research provided the first comprehensive comparison of microbial dynamics in ice-covered and ice-free Arctic waters, and showed that pelagic microbial communities in are strongly impacted by the presence of sea ice and differ between waters of Arctic and Atlantic origins. Overall,  my PhD thesis contributed to the baseline knowledge needed for further long-term observations of pelagic microbial communities in the Arctic marine ecosystem, and underlined the potential impact of further environmental changes on the Arctic Ocean in the light of prevalent global warming and climate change.

MSc | Physiological and genomic characterization of biofilm forming Alteromonas macleodii strain

Heterotrophic bacterioplankton plays a central role in utilization and recycling of organic carbon in the ocean.  My masters thesis focused on characterization of a marine heterotrophic Gammaproteobacteria isolate - Alteromonas macleodii HOT1A3. Two traits of A. macleodii HOT1A3 were of specific interest: formation of floating biofilms in stationary phase cultures, and inhibition of Prochlorococcus growth in co-culture. To elucidate the mechanisms behind these two traits we sequenced,  fully assembled and annotated its genome. The fully closed genome (~4.5Mbp) allowed us to identify the presence of a large, 148kbp plasmid, pAM1A3. This plasmid consisted of an almost complete flexible genomic island, containing many genes involved in metal resistance, previously found only in the genomes of the species Alteromonas mediterranea. These results suggested a remarkable wholesale genomic exchange between lineages of Alteromonas that belong to ecologically different populations or ecotypes.