Bacterioplankton of the Warta River in relation to physicochemical parameters and flow rate

Influence of changeable hydro‐meteorological conditions on dissolved organic carbon and bacterioplankton abundance in a hypertrophic reservoir and downstream river

“…During lower WLs and reduced discharge in the NR in 2009, a positive relation between BA and the concentration of chlorophyll a (Table V) confirmed the role of labile OM in development of bacterial communities. This type of dependencies was described by Szeląg-Wasielewska et al (2009) for Warta River. In confirmation, the relationships between BA and biological parameters were found only in 2009, when phytoplankton biomass (higher chlorophyll a concentration) in the SR and NR were higher (Table II).…”

“…Interestingly, riverine BA is much less dependent on hydrological parameters than the bacterioplankton in the reservoir (Table ). No such correlations were found for much bigger Warta River (Szeląg‐Wasielewska et al , ). According to previously observed dependencies between DOC and BA (Tranvik ; Karlsson et al , ), no such relations were noted in the investigated reservoir or in the river in 2009 and 2010, thus, our findings contradict these relations.…”

“…Bacterioplankton abundance values found in the NR were typical or even higher than those of lowland rivers in the temperate zone (Liu and Leff ; Klammer et al , ; Szeląg‐Wasielewska et al , ; Table ). Temporal variations of BA were influenced by changes of WL in the reservoir (Table ); however, in the case of the NR, especially its upper course, because of artificially regulated discharge through the dam on the SR, the natural variations of BA are mostly disturbed and undoubtedly determined by bacterial sources of the reservoir (Figure ).…”

“…This type of dependencies was described by Szeląg‐Wasielewska et al . () for Warta River. In confirmation, the relationships between BA and biological parameters were found only in 2009, when phytoplankton biomass (higher chlorophyll a concentration) in the SR and NR were higher (Table ).…”

“…Most DOC in lowland surface waters originates from the catchment, similar to natural bacterioplanktona typical community of aquatic organisms playing an important role in organic matter (OM) mineralization (Tranvik, 1988;Karlsson et al, 2001). Despite the significance of bacterioplankton in the functioning of all types of aquatic ecosystems, the majority of research on these organisms was done in lakes (Pace et al, 1990;Chróst and Siuda, 2006), seas and oceans (Azam et al, 1993;Li et al, 2004;Romera-Castillo et al, 2011), with little discussion about the role of both DOC and bacterioplankton in rivers (Szeląg-Wasielewska et al, 2009), probably because higher hydrological diversity is making data interpretation difficult. No reports are available on DOC and bacterioplankton in rivers where the hydrological regime is disturbed by the dams.…”