Geographic Patterns of Bacterioplankton among Lakes of the Middle and Lower Reaches of the Yangtze River Basin, China

Abstract

The revolution of molecular techniques has revealed that the composition of natural bacterial communities normally includes a few abundant taxa and many rare taxa. Unraveling the mechanisms underlying the spatial assembly process of both abundant and rare bacterial taxa has become a central goal in microbial ecology. Here, we used high-throughput sequencing to explore geographic patterns and the relative importance of ecological processes in the assembly of abundant and rare bacterial subcommunities from 25 lakes across the middle and lower reaches of Yangtze River basin (MLYB), located in Southeast China, where most of the lakes are interconnected by river networks. We found similar biogeographic patterns of abundant and rare subcommunities which could significantly distinguish the community compositions of the two lake groups that were far from each other but which could not distinguish the community compositions of the nearby lakes. Both abundant and rare bacteria followed a strong distance-decay relationship. These findings suggest that the interconnectivity between lakes homogenizes the bacterial communities in local areas, and the abundant and rare taxa therein may be affected by the same ecological process. In addition, based on the measured environmental variables, the deterministic processes explain a small fraction of variation within both abundant and rare subcommunities, while both neutral and null models revealed a high stochasticity ratio for the spatial distribution patterns of both abundant and rare taxa. These findings indicate that the stochastic processes exhibited a greater influence on both abundant and rare bacterial subcommunity assemblies among interconnected lakes. IMPORTANCE The middle and lower Yangtze Plain is a typical floodplain in which many lakes connect with each other, especially in the wet season. More importantly, with the frequent change of regional water level in the wet season, there is a mutual hydrodynamic exchange among these lakes. The microbial biogeography among these interconnected lakes is still poorly understood. This study aims to unravel the mechanisms underlying the assembly process of abundant and rare bacteria among the interconnected lakes in the middle and lower Yangtze Plain. Our findings will provide a deeper understanding of the biogeographic patterns of rare and abundant bacterial taxa and their determined processes among interconnected aquatic habitats.

Distinct Community Assembly Processes of Abundant and Rare Soil Bacteria in Coastal Wetlands along an Inundation Gradient

“…We found a significantly lower rate of community turnover in RT than in AT ( Fig. 1 ), which was consistent with prior studies based on RT in the Yangtze River basin ( 51 ) as well as in lakes and reservoirs across China ( 14 , 17 , 18 ). On one hand, RT can become dominant under favorable environmental conditions ( 7 ), evolve to adapt to environmental changes, and increase the community resistance to environmental disturbances ( Fig.…”

Geographic pattern of phytoplankton community and their drivers in lakes of middle and lower reaches of Yangtze River floodplain, ChinaGeographic pattern of phytoplankton community and their drivers in lakes of middle and lower reaches of Yangtze River floodplain, China

“…By the year of 2009, over 47,000 dams have been built in the Yangtze River basin (Wang et al 2019). Contrarily, bacterioplankton community tended to cluster together in the lakes with small distance in MLYR oodplain (Bai et al 2020). Bacterioplanktons in Jiangsu lakes shared high similarities, but exhibited signi cant dissimilarities from those in Anhui, Jiangxi, and Hubei lakes.…”

“…S9). The MLYR lakes were connected to some degrees, inland lakes were separated by dry land, and hydrodynamic gradients existed among these lakes (Bai et al 2020). Additionally, a large number of dams built for reservoirs and ood control also acted as the barriers for the exchange of hydrodynamics among lakes.…”

“…The middle and lower reaches of the Yangtze River basin are featured as the typical oodplain in which many shallow lakes connect with each other through intricate river networks (Yin et al 2007). Particularly in the wet season, the frequent change of regional water level induces a mutual hydrodynamic exchange among these lakes, nally resulting in spatial destructuring and limnological homogenization (Bai et al 2020;Thomaz et al 2007). The oodplain lakes provide a good system to test the metacommunity theory for these lakes that are highly dynamic ecosystems with a wide diversity of habitats, as well as in their degree of connectivity (Ward and Tockner 2001).…”

Distinct microhabitats affect the relative balance of ecological processes shaping the spatial distribution of bacterial communities in lakeshore habitats

“…It describes how the similarity of community composition decreases with the increasing geographic distance between the communities (Morlon et al, 2008;Nekola & White, 1999), which has been confirmed in various habitats (Bai et al, 2020;Hayden & Beman, 2016;Jiao et al, 2019;Liu et al, 2015;Wu et al, 2019;Xiao et al, 2018). Bacterioplankton communities have shown significant DDRs in freshwater lakes at a regional scale (Bai et al, 2020). However, whether bacterial communities exhibit similar DDRs in lakeshore habitats remains unknown.…”