Analysis and evolution of water quality of the upper Váh River (northern Slovakia) by long-term changes in the community structure of ciliates (Protista: Ciliophora)

Abstract

A long-term monitoring of the upper Váh River was carried out in order to evaluate evolution of water quality by means of ciliate taxocoenoses. One sampling station (Lisková) was located upstream of the pulp and paper mill in the town of Ružomberok, while two stations (Bystrá and Stankovany) were situated downstream of Ružomberok. Benthic samples were collected three times a year at each station during 2004-2011. This long-term study enabled us to assemble a comprehensive checklist of ciliates recorded in the upper Váh, and to characterize and compare the ciliate communities in the investigated watercourse. The saprobic index and valency analysis of the ciliate communities allowed us to quantify organic input and to evaluate changes in the saprobity of the upper Váh. The saprobic index ranged from 2.45 to 3.66 corresponding to the quality classes II-IV. Further, there was a prevalence of the α-and β-mesosaprobic levels, but during some periods the polysaprobic level increased along with the decrease of the β-mesosaprobic level. Beside the organic pollution, toxic contaminations were also noticed several times in the studied watercourse. This was documented by a significant drop in the species diversity and abundance of ciliates as well as by various morphological malformations and movement disorders of ciliates and other microorganisms. However, the negative effect of toxic and/or organic pollution wore off relatively quickly, indicating a good self-purification capability of the river.

Complexity of river ciliate communities at a national park highlights the need for microbial conservation

“…In the present study, only seven of the species (8% of the total) were common to the three locations sampled, and a high proportion of the species (ranging from 29% to 57% depending on the river site) were found only once in the study and with only one individual. These results are somewhat similar to those reported by Madoni and Bassanini (), Madoni and Braghiroli () and Tirjaková and Vďačný (), although the proportions of the species found only once in this study were generally higher than previously recorded.…”

“…These results are somewhat similar to those reported by Madoni and Bassanini (1999), Madoni and Braghiroli (2007) and Tirjaková and Vďačný (2013), although the proportions of the species found only once in this study were generally higher than previously recorded.…”

“…mL -1 at RS1 to Max. 166 ind mL -1 at RS3) are in line with average values reported by most studies except Packroff and Zwick (1998) and Tirjaková and Vďačný (2013), who both reported abundances more than one to two orders of magnitude higher. The results reported here show a higher abundance of ciliates per gram dry weight (DW) of sediment, than those found by Königs and Cleven (2007).…”

Structure and dynamic of planktonic ciliate community in a large Neotropical river: the relevance of the pluviosity and tributaries in the biodiversity maintenance

“…A total of 117 planktonic ciliate taxa were registered, a regional diversity similar to others found in studies on lotic environments (Kiss et al, 2009;Tirjaková & Vďačný, 2013). On the other hand, when considering the local diversity, we recorded only four species per sample, in average.…”

“…In continental aquatic ecosystems, biodiversity is affected by the geographical variation in fluvial processes and modifications due to disturbance regimes, such as hydrological retention, connectivity, geomorphological complexity and nutrient input, both from the riparian zone and from the river basin (Poff et al, 2007;Thorp et al, 2008). In river-floodplain systems, changes in the hydrological regime (floods) are considered the main driving forces affecting biodiversity (Thomaz et al, 2007).…”