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Light-dependent germination and subsequent proliferation of N2-fixing cyanobacteria in a large shallow lake
Published online by Cambridge University Press: 03 May 2012
Abstract
Cyanobacteria are a worldwide group of photosynthetic prokaryotes that can cause nuisance blooms in eutrophic waters. It is generally accepted that their resting cells, akinetes, play an important role in the dispersal, recruitment, initiation of blooms and survival under unfavourable conditions, therefore information on the germination, distribution and abundance of akinetes in natural sediments is essential for understanding the ecology and bloom dynamics of N2-fixing cyanobacteria. The present study describes the effect of irradiance on the germination and subsequent growth of N2-fixing filamentous cyanobacteria developed from natural akinete stock in sediment of Lake Balaton (Hungary) with varying phosphorous supply. The research focuses on the invasive Cylindrospermopsis raciborskii and Aphanizomenon flos-aquae the most abundant species of this lake. In the experiments, the germination of ten filamentous N2-fixing cyanobacteria species was observed. The species assemblages of the germinated cyanobacteria populations showed strong light and phosphorus dependence. Anabaena and Anabaenopsis species became dominant in phosphorous-rich conditions, while in phosphorus-deficient environments Aphanizomenon species and C. raciborskii dominated. Among the germinated filaments we have detected Anabaenopsis cunningtonii and Anabaena compacta, which have not been observed in Lake Balaton previously. Our results suggest that among the filamentous heterocytic cyanobacteria of this shallow lake the invasive C. raciborskii was the best competitor when phosphorus supply and irradiance were low.
Keywords
- Type
- Research Article
- Information
- Annales de Limnologie - International Journal of Limnology , Volume 48 , Issue 2 , 2012 , pp. 177 - 185
- Copyright
- © EDP Sciences, 2012
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