Microbial community changes induced by Managed Aquifer Recharge activities: linking hydrogeological and biological processes

Abstract

Abstract. Managed Aquifer Recharge (MAR) is a technique used worldwide to increase the availability of water resources. We study how MAR modifies microbial ecosystems and its implications for enhancing biodegradation processes to eventually improve groundwater quality. We compare soil and groundwater samples taken from a MAR facility located in NE Spain during recharge (with the facility operating continuously for several months) and after 4 months of no recharge. The study demonstrates a strong correlation between soil and water microbial prints with respect to sampling location along the mapped infiltration path. In particular, managed recharge practices disrupt groundwater ecosystems by modifying diversity indices and the composition of microbial communities, indicating that infiltration favors the growth of certain populations. Analysis of the genetic profiles showed the presence of nine different bacterial phyla in the facility, revealing high biological diversity at the highest taxonomic range. In fact, the microbial population patterns under recharge conditions agree with the intermediate disturbance hypothesis (IDH). Moreover, DNA sequence analysis of excised denaturing gradient gel electrophoresis (DGGE) band patterns revealed the existence of indicator species linked to MAR, most notably Dehalogenimonas sp., Nitrospira sp. and Vogesella sp.. Our real facility multidisciplinary study (hydrological, geochemical and microbial), involving soil and groundwater samples, indicates that MAR is a naturally based, passive and efficient technique with broad implications for the biodegradation of pollutants dissolved in water.

Coalescence of bacterial groups originating from urban runoffs and artificial infiltration systems among aquifer microbiomes

“…Urbanization exerts multiple pressures on natural habitats and particularly on aquatic environments (Konrad and Booth, 2005;McGrane, 2016;Mejía and Moglen, 2009). The densification of urban areas, combined with the conversion of agricultural and natural lands into urban land use, led to the replacement of vegetation and open fields by impervious urban structures (i.e., roads, rooftops, sidewalks and parking lots) ( Barnes et al, 2001). These impervious structures reduce the infiltration capacity of soils.…”

“…Due to these consequences, stormwater infiltration systems (SISs) or managed aquifer recharge (MAR) systems have been developed over the last decades and are gaining more interest in developed countries (Pitt et al, 1999). Such practices reduce direct stormwater discharges to surface waters and alleviate water shortages (Barba et al, 2019;Dillon et al, 2008;Marsalek and Chocat, 2002). However, stormwater represents a major source of nonpoint pollution, and its infiltration into the ground may have adverse ecological and sanitary impacts (Chong et al, 2013;Pitt et al, 1999;Vezzaro and Mikkelsen, 2012).…”

“…The filtering properties of a SIS are influenced by various abiotic factors such as the nature of the media (rocks, sand and other soil elements), the physical properties (e.g., granulometry, hydrophobicity index and organization) and the runoff water flow velocity (Lassabatere et al, 2006;Winiarski et al, 2013). These constraints will impact not only the water transit time from the top layers to the aquifer but also the biological properties of these systems including the plant cover, root systems, worm population and composition of microbiota (Barba et al, 2019;Bedell et al, 2013;Crites, 1985;Pigneret et al, 2016). The thickness of the vadose zone was found to be one of the key parameters explaining chemical transfers such as phosphate and organic-carbon sources (Voisin et al, 2018).…”

“…The thickness of the vadose zone was found to be one of the key parameters explaining chemical transfers such as phosphate and organic-carbon sources (Voisin et al, 2018). The situation is much less clear regarding the microbiological communities that flow through these systems (e.g., Barba et al, 2019;Voisin et al, 2018).…”

Temporal and Spatial Diversity of Renewable Groundwater Resources in the River Valley

“…The methods of assessing the amount of infiltration recharge on a regional scale are the subject of many hydrogeological studies, and the synthesis was presented in some publication [2,[9][10][11]. Groundwater infiltration recharge is a complex process that depends on many factors, including climatic conditions and the dynamics of their changes [12][13][14][15], permeability and texture of soils and the vadose zone [16][17][18][19], slope gradient and terrain relief [20][21][22], land use/land cover [10,14,[23][24][25], thickness of the vadose zone [19,26] and factors associated with biological and microbial activity in the vadose zone [27][28][29].…”