User:Friederike Heinrich

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Friederike Heinrich


PhD student (Limnology [[1] [[2]], [[3]], Dept. Ecology and Evolution [[4]], Uppsala University [[5]])

Research interest: Ecology of Alphaproteobacteria in aquatic systems'

The project focuses on the role of α-Proteobacteria in aquatic ecosystems. Of particular interest are freshwater α -Proteobacteria and in particular their ecophysiology and their ability to cope with environmental changes/disturbances. Bacterial taxa belonging to the "Alphaproteobacteria" (about 140 genera and 425 species at present) are extremely morphologically and metabolically diverse.

            Image:Alpha tree 1.jpg

A variety of metabolic strategies are found in this subclass, including photosynthesis, nitrogen fixation, ammonia oxidation, and methylotrophy. Stalked, stellate, and spiral morphologies are found. Members of this subclass also play key roles in carbon, sulphur and nitrogen cycles in a wide range of habitats.

Alphaproteobacteria are widely distributed in various aquatic and terrestrial environments. It is thought so far that α-Proteobacteria do not play a such important role in freshwater systems compared with marine systems where organisms like Roseobacter or Pelagibacter ubique are thought to be of most importance to the ecosystem. However sequences (cluster LD12) closely related, but still clearly phylogenetically separated from the marine cluster SAR11 [6]has been detected in several investigations via clone libraries or DGGE band sequences. In marine environments α-Proteobacteria (markedly the SAR11 cluster) are extremely abundant, grow slowly and seem to be unable to respond to rapid changes in substrate availability and other resources.

Of main interest in this project is to figure out the specific distribution and abundance of typical freshwater microorganisms and to isolate representative α-Proteobacteria. The ecology of the obtained isolates is studied at the population and single-cell level. As a result of the distribution and abundance survey, environmental conditions and changes which seem to be relevant / important for the biology of the typical α-Proteobacteria in nature are identified for detailed studies in controlled laboratory experiments to observe their ecophysiological responses. In addition to environmental surveys and efforts to cultivate representative freshwater α-Proteobacteria, α-proteobacterial models (e.g. Caulobacter crescentus as a well studied freshwater organotroph with several marine members) are used in lab experiments mimicking chancing environments (like temperature or nutrients supply)

Tools like Card-FISH [[7]], Mar-FISH [[8]]and qPCR [[9]] are used to study how freshwater α-Proteobacteria bacteria respond to environmental fluctuations at the community, population and single-cell level.

some more research interests:

  • Success in cold waters: patchiness and environmental control of marine bacterial populations in the Southern Ocean (Cooperation with Kalmar University [[10]]
  • Meaning of cell shape in aquatic systems - Why are so many bacteria C-shapes? (Cooperation with Dept. Cell and Molecular Biology, Microbiology, University Uppsala [[11]]
  • Formaldehyde degradation in aquaculture biofilters Cooperation with Dept. Cell and Molecular Biology, Microbiology, University Uppsala [[12]]
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