Characterization of the bacterioplankton community and the influencing factors in the upper reaches of the Han River basin

Abstract

The upper reaches of the Han River are the source region of water for the Middle Route of China's South-to-North Water Diversion Project, mainly for household, industrial, and irrigation purposes. Planktonic bacteria are more sensitive than macroorganisms to water physical and chemical properties and play a critical role in biogeochemical processes in river ecosystems. In November 2017 and April 2018, a systematic and methodical survey was carried out to evaluate the water quality and bacterial communities, on the mainstem of the Han River and its ve main tributaries. In this study, high-throughput sequencing technology has been employed to investigate the bacterioplankton community composition. The results indicated that: 1) Diversity increased downstream, especially in the upper reaches of the Han River. 2) The relative abundance of Actinobacteria increased with the increase of river length, while that of Bacteroidetes decreased slightly. 3) Five tributaries were found to be importance sources of taxa to the Han River, however in both months a large proportion of OTUs (37.84% and 36.34%, respectively) had unknown sources. 4) Finally, redundancy analysis (RDA) and Bioenv analysis showed that environmental parameters (pH, TN, Cond, NH 4 + -N, DO, NO 2 − -N, Chl-a and T) had a great in uence (p ≤ 0.05) on the bacterioplankton community. These research results are bene cial for the managing the ecological system, protecting the tributary biodiversity, and conserving the mainstem and tributaries of the Han River basin.

The Seasonal Patterns, Ecological Function and Assembly Processes of Bacterioplankton Communities in the Danjiangkou Reservoir, China

“…The above results indicate that N and P nutrients are the main factors driving the communities and function of bacterioplankton in the DJR. Similar to other lakes and reservoirs, T, pH, COD, COD Mn , Cond, and Chla are also important factors affecting the composition of the bacterioplankton communities in the DJR ( Liu et al, 2015 ; Chen Z. J. et al, 2020 ; Dong et al, 2020 ; Qian-Qian et al, 2021 ; Sun et al, 2021 ).…”

“…The results indicated that Actinobacteria, Bacteroidetes, and Cyanobacteria were the dominant populations. Sun et al (2021) analyzed Han River bacterioplankton upstream of the DJR. The results showed that the dominant genera were Flavobacterium , Planktophila , and Siphonobacter .…”

“…In our previous study, HTS was employed for bacterioplankton community composition and influencing factors in the DJR, found that the bacterioplankton community were composed of 27 phyla and 336 genera and that TN, pH, COD, and COD Mn can significantly affect bacterioplankton community composition ( Chen Z. J. et al, 2020 ). Sun et al (2021) studied the composition of bacterioplankton in the upstream river of the DJR and reported that environmental parameters such as pH, TN, Cond, and NH 4 + –N significantly affected the composition of the bacterioplankton communities. The dry season at the DJR occurs from February to July, and the wet season occurs from August to January of the following year.…”

Dynamics of Bacterioplankton Communities during Wet and Dry Seasons in the Danjiangkou Reservoir in Hubei, China

“…Bacterioplankton play a significant role in various geochemical cycles and in the transport of carbon to the microbial food web occurring in aquatic ecosystems such as rivers, water channels, reservoirs, and lakes [ 29 , 30 ]. Bacterioplankton communities’ compositions can serve as indicators of aquatic environmental conditions since they are typically responsive to environmental instabilities and water quality [ 15 , 19 , 31 , 32 , 33 ]. Studies revealed that the bacterioplankton communities’ compositions can be influenced in response to spatiotemporal and environmental changes [ 30 , 34 ].…”

“…However, Acinetobacter, Exiguobacterium, and Planomicrobium were the dominant genera in WH and WD samples, while unclassified and other genera were abundant in DH and DD samples. In previous studies, these dominant phyla and genera have also displayed significant seasonal and spatial differences in various aquatic environments and their potential association with the water quality [ 28 , 30 , 32 , 40 ]. Furthermore, studies have also reported good water quality during the dry season as compared with the wet season [ 1 , 3 , 41 ].…”