@article{WannickeFrindteGustetal.2015,
  author    = {Wannicke, Nicola and Frindte, Katharina and Gust, Giselher and Liskow, Iris and Wacker, Alexander and Meyer, Andreas and Grossart, Hans-Peter},
  title     = {Measuring bacterial activity and community composition at high hydrostatic pressure using a novel experimental approach: a pilot study},
  series = {FEMS microbiology ecology},
  volume    = {91},
  journal   = {FEMS microbiology ecology},
  number    = {5},
  publisher = {Oxford Univ. Press},
  address   = {Oxford},
  issn      = {0168-6496},
  doi       = {10.1093/femsec/fiv036},
  pages     = {15},
  year      = {2015},
  abstract  = {In this pilot study, we describe a high-pressure incubation system allowing multiple subsampling of a pressurized culture without decompression. The system was tested using one piezophilic (Photobacterium profundum), one piezotolerant (Colwellia maris) bacterial strain and a decompressed sample from the Mediterranean deep sea (3044 m) determining bacterial community composition, protein production (BPP) and cell multiplication rates (BCM) up to 27 MPa. The results showed elevation of BPP at high pressure was by a factor of 1.5 +/- 1.4 and 3.9 +/- 2.3 for P. profundum and C. maris, respectively, compared to ambient-pressure treatments and by a factor of 6.9 +/- 3.8 fold in the field samples. In P. profundum and C. maris, BCM at high pressure was elevated (3.1 +/- 1.5 and 2.9 +/- 1.7 fold, respectively) compared to the ambient-pressure treatments. After 3 days of incubation at 27 MPa, the natural bacterial deep-sea community was dominated by one phylum of the genus Exiguobacterium, indicating the rapid selection of piezotolerant bacteria. In future studies, our novel incubation system could be part of an isopiestic pressure chain, allowing more accurate measurement of bacterial activity rates which is important both for modeling and for predicting the efficiency of the oceanic carbon pump.},
  language  = {en}
}
@article{TittelWiehleWannickeetal.2009,
  author    = {Tittel, Joerg and Wiehle, Ines and Wannicke, Nicola and Kampe, Heike and Poerschmann, Juergen and Meier, Jutta and Kamjunke, Norbert},
  title     = {Utilisation of terrestrial carbon by osmotrophic algae},
  issn      = {1015-1621},
  doi       = {10.1007/s00027-008-8121-2},
  year      = {2009},
  abstract  = {Terrestrial-derived dissolved organic carbon (DOC) contributes significantly to the energetic basis of many aquatic food webs. Although heterotrophic bacteria are generally considered to be the sole consumers of DOC, algae and cyanobacteria of various taxonomic groups are also capable of exploiting this resource. We tested the hypothesis that algae can utilise DOC in the presence of bacteria if organic resources are supplied in intervals by photolysis of recalcitrant DOC. In short-term uptake experiments, we changed irradiation in the range of minutes. As model substrates, polymers of radiolabelled coumaric acid (PCA) were used, which during photolysis are known to release aromatic compounds comparable to terrestrial-derived and refractory DOC. Three cultured freshwater algae readily assimilated PCA photoproducts equivalent to a biomass-specific uptake of 5-60\% of the bacterial competitors present. Algal substrate acquisition did not depend on whether PCA was photolysed continuously or in intervals. However, the data show that photoproducts of terrestrial DOC can be a significant resource for osmotrophic algae. In long-term growth experiments, interval light was applied one hour per day. We allowed cultured Chlamydomonas to compete for ambient DOC of low concentration. We found higher abundances of Chlamydomonas when cultures were irradiated intermittently rather than continuously. These data suggest that photolysis of DOC supports algal heterotrophy, and potentially facilitates growth, when light fluctuations are large, as during the diurnal light cycle. We concluded that osmotrophic algae can efficiently convert terrestrial carbon into the biomass of larger organisms of aquatic food webs.},
  language  = {en}
}