Seasonality Affects the Diversity and Composition of Bacterioplankton Communities in Dongjiang River, a Drinking Water Source of Hong Kong

Abstract

Water quality ranks the most vital criterion for rivers serving as drinking water sources, which periodically changes over seasons. Such fluctuation is believed associated with the state shifts of bacterial community within. To date, seasonality effects on bacterioplankton community patterns in large rivers serving as drinking water sources however, are still poorly understood. Here we investigated the intra-annual bacterial community structure in the Dongjiang River, a drinking water source of Hong Kong, using high-throughput pyrosequencing in concert with geochemical property measurements during dry, and wet seasons. Our results showed that Proteobacteria, Actinobacteria, and Bacteroidetes were the dominant phyla of bacterioplankton communities, which varied in composition, and distribution from dry to wet seasons, and exhibited profound seasonal changes. Actinobacteria, Bacteroidetes, and Cyanobacteria seemed to be more associated with seasonality that the relative abundances of Actinobacteria, and Bacteroidetes were significantly higher in the dry season than those in the wet season (p < 0.01), while the relative abundance of Cyanobacteria was about 10-fold higher in the wet season than in the dry season. Temperature and NO3--N concentration represented key contributing factors to the observed seasonal variations. These findings help understand the roles of various bacterioplankton and their interactions with the biogeochemical processes in the river ecosystem.

Spatial Variation in Bacterioplankton Communities in the Pearl River, South China: Impacts of Land Use and Physicochemical Factors

“…The predominant bacterioplankton communities in the Pearl River were Proteobacteria and Actinobacteria, which accounted for more than half the total abundance. This finding is consistent with previous river-based studies [ 17 , 40 , 41 , 42 , 43 ]. Proteobacteria play an important role in aquatic carbon and nitrogen cycling [ 44 ] and are dominant microorganisms in freshwater environments [ 42 ].…”

Aquatic Bacterial Communities Associated With Land Use and Environmental Factors in Agricultural Landscapes Using a Metabarcoding Approach

“…Since the metabolism of bacterial communities contribute significantly to biogeochemical cycles (Newton et al, 2011 ; Staley et al, 2014 ; Amado and Roland, 2017 ), the capacity of an aquatic ecosystem to assimilate, dissipate, and ultimately be biologically resilient to pollutant pressures and hydro-physical changes, will depend largely upon the diversity and composition of the microbiota and their functional characteristics (i.e., photosynthesis and the oxidation, degradation, and/or fermentation of inorganic and organic substances; Das and Chandran, 2010 ; Schenker, 2014 ; Kumar, 2015 ). DNA-based work has been carried out to, assess the aptitude and effectiveness of both autochthonous and allochthonous microbes to degrade or utilize carbon resources (Das and Chandran, 2010 ; Jurelevicius et al, 2013 ; García-Armisen et al, 2014 ), detect sources of fecal pollution in water, and to evaluate the nature and status of other water quality properties and conditions (Ibekwe et al, 2013 ; Pandey et al, 2014 ; Ramírez-Castillo et al, 2015 ; Sales-Ortells et al, 2015 ; Sun et al, 2017 ).…”

Changes in Microbial Community Structures under Reclaimed Water Replenishment Conditions

“…Nutrients including ammonia nitrogen, nitrate and phosphate had a great influence in different samples. In addition, nitrate had a closely positive correlation with flowing reclaimed water in device A, and ammonia nitrogen had a closely positive correlation with still water in devices B and C. For inorganic ions, Na + and SO4 2− were closely correlated with flowing reclaimed water; however, Clwas correlated with the still water in devices B and C. Nitrogen nutrients have been suggested to be the dominant factors affecting the community structure in the Dongjiang River [51] and the tributary of the Three Gorges reservoir [62]. Nitrogen fixation, ammoniation, nitrification and denitrification in nature are all inseparable from the participation of microorganisms [63].…”

“…On day 10 (10A_RW), the relative abundance of Proteobacteria increased suddenly, but Actinobacteria and Cyanobacteria decreased to the lowest abundance. Proteobacteria have been confirmed to be typical and dominant freshwater microbes in aquatic habitats, including rivers and lakes [51]. Proteobacteria may adapt well to changes in the environment when fluidity increases compared to the habitat they lived in before [52].…”