Biology subjects

Adyari, B.

Publications and source records attributed to Adyari, B..

3 recordsLinked to original sources

bioRxiv2023

Strong cascading impacts of micropollutants on planktonic food web in urban river

Urban rivers rely on intricate multitrophic interactions in food webs, which are vital for ecological functions. Human-induced pollutant discharge, notably micropollutants, poses a threat to these interactions. To study the impact of micropollutants on the microbial food web, we sampled downstream areas of the Jiulong Rivers north tributary (lower urbanization, [~]25% built land) and west tributary (higher urbanization, [~]65% built land) for eleven consecutive days in both dry and wet seasons in Fujian, China. We constructed a conceptualized planktonic food web model by employing DNA metabarcoding targeting bacteria, micro-eukaryotes (algae and protozoa), and microzooplankton. Our results revealed that the more urbanized west tributary exhibited significantly higher micropollutant concentrations. Structural equation modeling (SEM) incorporating micropollutants and all food web elements indicated a significantly stronger impact of micropollutants on the planktonic food web in the west tributary than in the north tributary. Micropollutants exhibited both direct and indirect (cascade) effects on high trophic levels (protozoa and microzooplankton), with algal communities mediating the cascade effects instead of bacterial communities, likely due to the increased eutrophication in the urbanized tributary. Overall, our study underscores the potential ecological disruptions caused by micropollutants in shaping planktonic food web interactions in urban rivers. SynopsisUrban rivers face ecological threats from micropollutants. This study shows elevated micropollutants significantly affected the planktonic food webs. Algal, rather than bacterial, food web pathway mediated micropollutants cascading effects on high trophic levels, emphasizing micropollutant-induced disruptions in urban rivers.

ecology↗

bioRxiv2023

Mass-immigration shapes the antibiotic resistome of wastewater treatment plants

Wastewater treatment plants (WWTPs) are the hotspots for the spread of antibiotic resistance genes (ARGs) into the environment. Nevertheless, a comprehensive assessment of the city-level and short-term daily variations of ARG surveillance is still lacking in WWTPs. Here, 285 ARGs and ten mobile gene elements (MGEs) were monitored in seven WWTPs in Xiamen via high-throughput qPCR (HT-qPCR) for seven days. The average daily load of ARGs to WWTPs was about 1.21 x 1020 copies/d, and a total of 1.44 x 1018 copies/d was discharged to the environment across the entire city. Interestingly, no daily variations were observed in ARG richness, abundance, and community composition. Stochastic processes were the main force determining the assembly of ARG communities, with their relative importance ranked in the order of influent (INF) > effluent (EFF) > activated sludge (AS). Further analyses indicated that bacteria and ARGs from upstream treatment units played an increasingly dominant role in shaping ARG communities in AS and EFF, respectively, suggesting the importance of mass-immigration of bacteria and ARGs from the source on ARG transport in wastewater treatment units. This emphasizes the need to revise the way we mitigate ARG contamination but focus on the source of ARGs in urban wastewater.

microbiology↗

bioRxiv2022

Hydrological dynamics drive the transition of antibiotic resistance genes between particle-attached and free-living lifestyles in a deep freshwater reservoir

Despite the growing awareness of antibiotic resistance genes (ARGs) spreading in the environment, there is a knowledge gap on the fate and transport of ARGs in particle-attached (PA) and free-living (FL) lifestyles in deep freshwater ecosystems experiencing seasonal hydrological changes. Here, we examined the ARG profiles using high-throughput quantitative PCR in PA and FL lifestyles at four seasons representing two hydrological seasons (i.e., vertical mixing and thermal stratification) in the Shuikou Reservoir (SR), Southern China. The results indicated that seasonal hydrological dynamics were critical for influencing ARGs in PA and FL fractions, and the transition of ARGs between the two lifestyles. Although both PA and FL ARG profiles were likely to be shaped by horizontal gene transfer, PA and FL ARGs had different responses to the changes in physico-chemicals (e.g., nutrients and dissolved oxygen) caused by seasonal hydrological dynamics. The particle-associated niche (PAN) index revealed that there were 94 non-conservative ARGs (i.e., no preferences for PA and FL), 23 conservative ARGs that preferred PA lifestyle, and 16 conservative ARGs for FL lifestyle. A sharp decline in the number of conservative ARGs in stratified seasons suggests a hydrological dynamics-dependent transition of ARGs between two lifestyles. Remarkably, the conservative ARGs (in PA or FL lifestyle) were more closely related to bacterial OTUs in their preferred lifestyle compared to their counterpart lifestyle, suggesting a lifestyle-dependent ARG enrichment. Altogether, these findings enhance our understanding of the role of seasonal hydrological changes in the dissemination of ARGs in different size fractions in deep aquatic ecosystems.

ecology↗