Longitudinal changes in the bacterial community composition of the Danube River: a whole-river approach.

摘要: The Danube River is the second longest river in Europe, and its bacterial community composition has never been studied before over entire length. In this study, was determined by denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified portions 16S rRNA gene from a total 98 stations on (73 stations) major tributaries (25 stations), covering distance 2,581 km. Shifts were related to changes environmental conditions found comparison with physicochemical parameters (e.g., temperature concentration nutrients) chlorophyll (Chl a). total, 43 distinct DGGE bands detected. Sequencing selected revealed that phylotypes associated typical freshwater bacteria. Apparent richness varied between 18 32 correlated positively P-PO4 (r = 0.56) negatively Chl −0.52). An artificial neural network-based model explained 90% variation apparent using concentrations N-NO2 Black Sea as input parameters. Between cities Budapest Belgrade, significantly lower than other regions river, showed pronounced peak. Generally, developed gradually; however, an abrupt clear shift detected section phytoplankton bloom. Large impoundments did not have discernible effect water column. conclusion, riverine largely influenced intrinsic factors.