Spatial and temporal variability of bacterial communities in high alpine water spring sediments

Abstract

Water springs are complex, fragile and taxa-rich environments, especially in highly dynamic ecosystems such as glacier forefields experiencing glacier retreat. Bacterial communities are important actors in alpine water body metabolism, and have shown both high seasonal and spatial variations. Seven springs from a high alpine valley (Matsch Valley, South Tyrol, Italy) were examined via a multidisciplinary approach using both hydrochemical and microbiological techniques. Amplified ribosomal intergenic spacer analysis (ARISA) and electric conductivity (EC) measurements, as well as elemental composition and water stable isotopic analyses, were performed. Our target was to elucidate whether and how bacterial community structure is influenced by water chemistry, and to determine the origin and extent of variation in space and time. There existed variations in both space and time for all variables measured. Diversity values more markedly differed at the beginning of summer and then at the end; the extent of variation in space was prevalent over the time scale. Bacterial community structural variation responded to hydrochemical parameter changes; moreover, the stability of the hydrochemical parameters played an important role in shaping distinctive bacterial communities.

Towards a tracer-based conceptualization of meltwater dynamics and streamflow response in a glacierized catchment

“…The depleted signal in summer months (Table 6) suggests a role of snowmelt in groundwater recharge (Baraer et al, 2015;Fan et al, 2015;Xing et al, 2015) that was quantified in a previous study . At the same time, the relatively high EC during summer demonstrates solute concentration and suggests longer residence times and/or flow pathways (and thus long contact with the soil particles) of infiltrating meltwater before recharging the groundwater (Brown et al, 2006;Esposito et al, 2016). The similar coefficients of variations of the two tracers in summer and fall indicate fewer inter-seasonal differences in water inputs to the springs compared to the streams and suggest continuous groundwater recharge even at the end of the melting seasons, pointing out again to relatively long travel times and recharge times.…”

Microbial assemblages reflect environmental heterogeneity in alpine streams

“…To date, most studies of microbial ecology in alpine headwaters have emphasized ice-fed streams, and particularly those fed by surface glaciers (Freimann et al, 2013a;Ren, Gao, Elser, & Zhao, 2017;Wilhelm et al, 2013) with rare rock glacier examples (Fegel et al, 2016). However, there has been considerably less focus on other stream types (but see Esposito et al, 2016), and no comparisons across multiple stream types in the same geographic region have been made.…”

Integrated management of ash from industrial and domestic combustion: a new sustainable approach for reducing greenhouse gas emissions from energy conversion

“…Applying a range of tools might improve our understanding of mechanisms affecting the quality of water in ecosystems that are sensitive to various factors, including both natural and man-induced disturbances, such as the mountain rivers (Esposito et al 2016). The quality of water in general is the combination of the number of microorganisms, concentrations of chemical compounds, and physical properties; therefore, interdisciplinary studies provide the best effects in this respect.…”

“…The quality of water in general is the combination of the number of microorganisms, concentrations of chemical compounds, and physical properties; therefore, interdisciplinary studies provide the best effects in this respect. Combining hydrochemical testing with microbiological analyses of water can be a useful tool enabling multivariate analysis of obtained results, and it has proved useful in a number of studies on aquatic ecosystems, including high-alpine spring waters in Italy (Esposito et al 2016), groundwater of the Mamora basin in Morocco (Kabbour and Zouhri 2005), or groundwater of the Merdja plain in Algeria (Fehdi et al 2016). Harclerode et al (2013) successfully combined a geographical approach with microbiological and chemical analyses of water to track the point and non-point sources of contamination with E. coli in Texas.…”