Nitrogen cycling in marine cyanobacterial mats
In: Krumbein, W.E.; Paterson, D.M.; Zavazin, G. (Ed.) (2003). Fossil and Recent biofilms: a natural history of life on Earth. Kluwer Academic: Dordrecht. ISBN 978-1-4020-1597-7; e-ISBN 978-94-017-0193-8. XXI, 482 pp. https://dx.doi.org/10.1007/978-94-017-0193-8, more |
| Keyword | | | Author keywords | salt marsh; heterocystous Cyanobacterium; axogenic phototrophic bacterium; microcoleus chthonoplastes; structural cell material |
| Abstract | Cyanobacteria are a diverse group of photoautotrophic prokaryotes. Many species possess a versatile metabolism but their dominant physiology is a plant-type oxygenic photosynthesis, using two photosystems (PS I and PS II) connected in series, allowing them to utilize light as the only source of energy (Bryant, 1994; Whitton & Potts, 2000). Just like plants, cyanobacteria use H2O as the electron donor and evolve O2. CO2 serves as the carbon source and is fixed through the reductive pentose-phosphate pathway (Calvin cycle). It is partly used for the synthesis of structural cell material while another part is diverted to a glycogen-like storage polymer. This polysaccharide is mobilized in the dark and energy is generated through aerobic respiration. To some extend, dark metabolism allows even growth of the cyanobacterium. Under anaerobic conditions several species have been shown to generate energy by fermentation of glycogen (Stal & Moezelaar, 1997). Under anaerobic conditions in the light and in the presence of sulfide, several cyanobacteria are able to switch to anoxygenic photosynthesis, involving only PS I (Cohen et al., 1986). |
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