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| Titel |
A single cell nanoSIMS view on the transfer of fixed nitrogen to bacteria associated with filamentous N-fixing cyanobacteria in the Baltic Sea |
| VerfasserIn |
Birgit Adam, Niculina Musat, Helle Ploug, Cristina L. Moraru, Tomas Vagner, Gaute Lavik, Lubos Polerecky, Marcel M. M. Kuypers |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250056325
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| Zusammenfassung |
| The large filamentous cyanobacteria Aphanizomenon sp., Anabaena sp. and Nodularia sp. are
the three main nitrogen fixers in the Baltic Sea. These species form massive blooms in the
photic zone during summer, gaining the energy required for nitrogen fixation through
photosynthesis. Atmospheric dinitrogen is fixed in specialized cells, the so-called heterocysts,
and is rapidly transferred to the vegetative cells. Previous studies have reported, that attached
and free living microorganisms profit from the release of nutrients by the cyanobacteria.
However, up to now the transfer of fixed nitrogen from cyanobacterial cells to the associated
microorganisms has not been directly shown in the environment. In this study we used a
combination of stable isotope incubations, isotope ratio mass spectrometry and nanoscale
secondary ion mass spectrometry (nanoSIMS) to measure N and C-uptake by single
microbial cells associated with blooming cyanobacteria. By using Halogen in-situ
hybridization coupled to nano-scale secondary ion mass spectrometry (HISH-SIMS) we
identified the epibionts and the freeliving bacteria and at the same time measured
their nitrogen and carbon uptake rates. We show that the community of organisms
profiting from nutrient N and C release is dominated by bacterial members of the
Alphaproteobacteria, Gammaproteobacteria and Cytophaga as well as single celled
eukaryotes. These results show for the first time at a single cell level that fixed nitrogen
and carbon are rapidly transfered to the microbial community in the Baltic Sea. |
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