Responses of bacterial community structure and denitrifying bacteria in biofilm to submerged macrophytes and nitrate

Abstract

Submerged macrophytes play important roles in constructed wetlands and natural water bodies, as these organisms remove nutrients and provide large surfaces for biofilms, which are beneficial for nitrogen removal, particularly from submerged macrophyte-dominated water columns. However, information on the responses of biofilms to submerged macrophytes and nitrogen molecules is limited. In the present study, bacterial community structure and denitrifiers were investigated in biofilms on the leaves of four submerged macrophytes and artificial plants exposed to two nitrate concentrations. The biofilm cells were evenly distributed on artificial plants but appeared in microcolonies on the surfaces of submerged macrophytes. Proteobacteria was the most abundant phylum in all samples, accounting for 27.3–64.8% of the high-quality bacterial reads, followed by Chloroflexi (3.7–25.4%), Firmicutes (3.0–20.1%), Acidobacteria (2.7–15.7%), Actinobacteria (2.2–8.7%), Bacteroidetes (0.5–9.7%), and Verrucomicrobia (2.4–5.2%). Cluster analysis showed that bacterial community structure can be significantly different on macrophytes versus from those on artificial plants. Redundancy analysis showed that electrical conductivity and nitrate concentration were positively correlated with Shannon index and operational taxonomic unit (OTU) richness (log10 transformed) but somewhat negatively correlated with microbial density. The relative abundances of five denitrifying genes were positively correlated with nitrate concentration and electrical conductivity but negatively correlated with dissolved oxygen.

Dynamics of Bacterial Community Diversity and Structure in the Terminal Reservoir of the South-To-North Water Diversion Project in China

“…Compared with conventional denitrifying bacteria, Flavobacterium species can grow well and exhibit denitrification activity under aerobic conditions. Moreover, most of these strains are able to degrade organic matter via heterotrophic nitrification and metabolic activities [34,35]. In the present study, we found that Limnohabitans sp.…”

Do composition and diversity of bacterial communities and abiotic conditions of spring water reflect characteristics of groundwater ecosystems exposed to different agricultural activities?

“…Furthermore, formerly reported differences in phosphate concentrations (Hafouzov, ) cannot be supported by our data. Interestingly, nitrate, which we hypothesized would influence bacterial communities, is negatively correlated with strontium but had no significant effect on either the composition or diversity of bacterial communities, which is in contrast to results reported from other studies (Ben Maamar et al., ; Carrino‐Kyker, Smemo, & Burke, ; Ibekwe, Ma, & Murinda, ; Turlapati et al., ; Zhang et al., ). Nitrate might thus either not be a discriminating factor for the variation in BCC, or the effect of strontium overrides the effect of nitrate.…”

Growing edible mushrooms: a conversation between bacteria and fungi

“…Among the postulated roles of the most abundant bacteria in morel substrates, members from the genus Pseudomonas are posited to be involved in morel fructification as further discuss in next section (Liu et al, 2017;Noble et al, 2009). Other dominant genera from the phyla Proteobacteria, Geobacter and Rhodoplanes, could help to degrade organic compounds into carbon sources available for the morels (Berlemont and Martiny, 2015) and enhance the availability of metal ions such as iron and manganese for fungi and plants through metal-reducing activity and siderophore production (Jin et al, 2013;Kügler et al, 2019) or simply they are denitrifying bacteria that thrive in the presence of fungal exudates (Zhang et al, 2016a). Species from the phylum Acidobacteria have been described to play an important role in maintaining the acidic pH value of the soil and therefore, also influence the uptake of trace elements from substrates, whereas bacteria belonging to the phylum Bacteroidetes have been reported to have the capacity to degrade cellulose and chitin (Liu et al, 2017).…”