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| Titel |
Response of Nodularia spumigena to pCO2 – Part 3: Turnover of phosphorus compounds |
| VerfasserIn |
J. Unger, S. Endres, N. Wannicke, A. Engel, M. Voss, G. Nausch, M. Nausch |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 10, no. 3 ; Nr. 10, no. 3 (2013-03-05), S.1483-1499 |
| Datensatznummer |
250018137
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| Publikation (Nr.) |
 copernicus.org/bg-10-1483-2013.pdf |
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| Zusammenfassung |
| Diazotrophic cyanobacteria form extensive summer blooms in the Baltic Sea
driving the surrounding surface waters into phosphate limitation. One of the
main bloom-forming species is the heterocystous cyanobacterium Nodularia spumigena. N. spumigena exhibits
accelerated uptake of phosphate through the release of the extracellular
enzyme alkaline phosphatase whose activity also serves as an indicator of
the hydrolysis of dissolved organic phosphorus (DOP). The present study
investigated the utilisation of DOP and its compounds (e.g., ATP) by N. spumigena during
growth under different CO2 concentrations, in order to estimate
potential consequences of ocean acidification on the cell's supply with
phosphorus (P). Cell growth, the phosphorus pool, and four DOP compounds (ATP,
DNA, RNA, and phospholipids) were determined in three setups with different
CO2 concentrations (average 341 μatm, 399 μatm, and
508 μatm) during a 15-day batch experiment. The results showed stimulated
growth of N. spumigena and a rapid depletion of dissolved inorganic phosphorus (DIP) in
all pCO2 treatments. DOP uptake was enhanced by a factor of 1.32 at 399 μatm and of 2.25 at 508 μatm compared to the lowest CO2
concentration. Among the measured DOP compounds, none was found to
accumulate preferentially during the incubation or in response to a specific
pCO2 treatment. However, at the beginning 61.9 ± 4.3% of total
DOP were not characterised but comprised the most utilised fraction. This is
demonstrated by the decrement of this fraction to 27.4 ± 9.9% of
total DOP during the growth phase with a preference at high pCO2. Our
results indicate a stimulated growth of diazotrophic cyanobacteria at
increasing CO2 concentrations which is accompanied by increasing
utilisation of DOP as an alternative P source. |
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