Cyanobacteria in Geothermal Habitats

摘要: Recent advances in molecular biology enabled a much more detailed view of cyanobacteria that inhabit well-studied hot spring habitats. What seemed on the basis microscopy and culture methods to be relatively simple story became one which ismore complex. yet ordered. For example. 16S rRNA studies Yellowstonehot cyanobacterial mat. often thought constructed by single cosmopolitan Synechococcus species. revealed many populations. most probably spp., whose genetic diversity is considerable.Some closely related populations exhibited orderly distributions along thermal vertical gradients. provided evidence “speciation” thermophilic may have resulted. part, from adaptive radiation specialized ecotypes. These results correspond with previous descriptions temperature “strains” cultivated Oregon mat, raising interesting questions answered through analysis. example, are same found geographically isolated springs, or does limited dispersal also cause divergence ofcyanobacteria subsequent radiations independent lineages? Advances microelectrode technology views distribution dynamics light, oxygen sulfide within photic zone such mats, range ~0.5 mm > 1 cm thickness. increased our knowledge diel chemical changes including for dynamic migrations motile cyanobacteria. Microelectrode ofone Yellowstone mat additional specialization populations, led anew oxygenic photosynthesis Intensive localized strongly influences microenvironmental chemistry, whichin turnenhances photorespiration. While very active, these partition majority ofphotosynthate into polyglucose, as opposed macromolecules needed growth. Photoexcretion glycolate dark fermentation polyglucose result cross feeding fixed carbon heterotrophs. Thorough investigation few systems, using both contemporary traditional methods, providing sophisticated biodiversity, ecology evolution