Studies on methanogenesis from freshwater sediments have so far primarily focused on lake sediments. To expand our knowledge on the community composition of methanogenic archaea in river sediments, we studied the abundance and diversity of methanogenic archaea at two localities along a vertical profile (top 50 cm) obtained from sediment samples from Sitka stream (the Czech Republic). In this study, we compare two sites which previously have been shown to have a 10-fold different methane emission. Archaeal and methanogen abundance were analyzed by real-time PCR and T-RFLP. Our results show that the absolute numbers for the methanogenic community (qPCR) are relatively stable along a vertical profile as well as for both study sites. This was also true for the archaeal community and for the three major methanogenic orders in our samples (Methanosarcinales, Methanomicrobiales, and Methanobacteriales). However, the underlying community structure (T-RFLP) reveals different community compositions of the methanogens for both locations as well as for different depth layers and over different sampling times. In general, our data confirm that Methanosarcinales together with Methanomicrobiales are the two dominant methanogenic orders in river sediments, while members of Methanobacteriales contribute a smaller community and Methanocellales are only rarely present in this sediment. Our results show that the previously observed 10-fold difference in methane emission of the two sites could not be explained by molecular methods alone.

• Klíčová slova
• qPCR, T-RFLP, depth profile, mcrA, methanogen,
• MeSH
• Archaea klasifikace   genetika   metabolismus   MeSH
• biodiverzita * MeSH
• DNA archebakterií genetika   MeSH
• geologické sedimenty mikrobiologie   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• methan metabolismus   MeSH
• polymorfismus délky restrikčních fragmentů MeSH
• řeky mikrobiologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• DNA archebakterií MeSH
• methan MeSH

Peat bog lakes represent important ecosystems in temperate and boreal zones. We investigated the seasonal dynamics of the microbial community in two small peat bog lakes, Kuźnik Olsowy and Kuźnik Bagienny, located in western Poland. Fluorescence in situ hybridization analyses revealed that the bacterial community was dominated by Proteobacteria and Actinobacteria, in addition to a substantial number of archaea. An infrared epifluorescence analysis demonstrated that aerobic anoxygenic phototrophs (AAPs) constituted a significant fraction of bacterial plankton (1-19%). All the bacterial groups exhibited large seasonal changes whose course differed between the studied lakes. While chlorophyll had its maximum during winter or early summer, AAPs peaked in summer, when the growth of this group was stimulated by higher irradiance and elevated water temperatures.

• MeSH
• Archaea klasifikace   genetika   izolace a purifikace   MeSH
• Bacteria klasifikace   genetika   izolace a purifikace   MeSH
• hybridizace in situ fluorescenční MeSH
• jezera mikrobiologie   MeSH
• roční období MeSH
• společenstvo * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Polsko MeSH