Halophilic bacteria in a Lake Michigan drainage basin as potential biological indicators of chloride-impacted freshwaters.

Autor: Passante EK; School of Freshwater Sciences, University of Wisconsin Milwaukee, Milwaukee, WI, USA., Dechant LE; Department of Geosciences, University of Wisconsin Milwaukee, Milwaukee, WI, USA., Paradis CJ; Department of Geosciences, University of Wisconsin Milwaukee, Milwaukee, WI, USA., McLellan SL; School of Freshwater Sciences, University of Wisconsin Milwaukee, Milwaukee, WI, USA. Electronic address: mclellan@uwm.edu.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2022 Nov 10; Vol. 846, pp. 157458. Date of Electronic Publication: 2022 Jul 18.
DOI: 10.1016/j.scitotenv.2022.157458
Abstrakt: There are few biological indicators for freshwater systems subjected to high chloride levels. Freshwater systems receive many forms of chloride such as road salts (e.g., NaCl, CaCl 2 , MgCl 2 ), fertilizers (e.g., KCl), and year-round water softener pollution. The goal our study was to investigate Halomonadaceae populations as prospective biological indicators of chloride-impacted freshwaters. The bacterial family Halomonadaceae are halophiles that generally require the presence of salt to survive, which make them an attractive candidate in determining chloride impaired areas. Field sediment surveys assessed how salt tolerant and halophilic bacteria abundance corresponded to chloride and conductivity measurements. Colony forming unit (CFU) counts on modified M9 6% NaCl plates (w/v) at urbanized sites compared to the rural sites had highest counts during winter and spring when chloride concentrations were also highest. Select isolates identified as Halomonadaceae through 16S rRNA sequencing were kept as active cultures to determine the NaCl concentration and temperature preference that resulted in the isolates optimal growth. Isolates tested under 5 °C (cold) grew optimally in 2 % NaCl (w/v), whereas under 18 °C (warm), isolates showed optimal growth at 6 % NaCl. The majority of isolates had maximum growth in the warmer temperature, however, select isolates grew better in the cold temperature. Culture-independent methods were used and identified Halomonadaceae were widespread and permeant members of the microbial community in a Lake Michigan drainage basin. Quantitative polymerase chain reaction (qPCR) targeting Halomonadaceae genera demonstrated that abundance varied by site, but overall were present throughout the year. However, community sequencing revealed there were a large relative proportion of specific Halomonadaceae populations present in winter versus summer. Methods targeting salt tolerant bacteria and specific members of Halomonadaceae appears to be a promising approach to assess chloride-impacted areas to better understand the long-term ecological impacts as we continue to salinize freshwater resources.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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