F-Specific RNA Bacteriophage Transport in Stream Water: Hydro-Meteorological Controls and Association with Suspended Solids

Abstract

F-specific RNA bacteriophages (FRNAPHs) are commonly used as indicators of faecal and viral contamination in waters. Once they enter surface waters, the exact role of suspended solids, sediments and hydro-meteorological factors in their fluvial fate and transport is poorly understood, and long-term studies (e.g., over years) are lacking. In this study, FRNAPH concentrations and genogroup distribution were measured in the Orne River (France) during two years at weekly intervals, and during four storm runoff events. Hydro-meteorological driving factors were investigated at both time scales. FRNAPH concentrations and genogroups at different depths of a riverbank sediment core were also examined to better discriminate the origin of the faecal pollution. During low flows, the FRNAPH and the suspended solid transport were decoupled and the FRNAPH concentrations were mainly correlated with the air and water temperature. During storm runoff events, the FRNAPH concentrations only showed a significant correlation with conductivity, turbidity and water discharge. Despite the uncertainty of the predictions, multi parameter regression models using hydro-meteorological variables were suitable to predict log transformed FRNAPHs’ concentrations at low flows with a standard error of 0.46. Model performance using the storm runoff events dataset was low. This study highlights different driving factors at low flows and during storm runoff events, and the need to measure at both time scales to better understand phage transport dynamics in surface water.

Novel findings in context of molecular diversity and abundance of bacteriophages in wastewater environments of Riyadh, Saudi Arabia

“…The phage prevalence was found affected by temperature conditions being entirely undetectable at �29˚C. Similarly, bacteriophages abundance was reported elsewhere to be highly influenced by the environmental conditions and the presence of host cell [30,36,37]. For instance, the abundance level of Cyanobacteria was found increasing with temperature rise, resulting in the increase of the associated phage community that supports our results [38].…”

“…Despite the significantly low abundance of Dickeya virus Limestone and Ralstonia virus RSA1 in our samples, it indicated the probable low abundance of their hosts which are potential plant pathogens including Dickeya solani (causing blackleg and soft rot of potato) [ 47 ] and Ralstonia solanacearum (causing bacterial wilt of tomato) [ 48 ]. The high diversity of phages among different isolation times and areas can affect the isolates quality as well as quantity due to environmental pressures [ 13 , 31 , 37 ].…”