Abundant and Rare Bacterioplankton in Freshwater Lakes Subjected to Different Levels of Tourism Disturbances

Congcong Jiao,Jin Zeng,Xinyi Cao,Yuqing Lin,Rui Huang,Wenjie Zhao,Dayong Zhao

doi:10.3390/w10081075

Abstract

Anthropogenic disturbances have a negative impact on lake ecosystems, such as water environmental degradation. Bacterioplankton communities are essential components in lakes and consist of a few abundant species and several rare taxa. However, little is known about the community diversity and composition of abundant and rare bacterioplankton subjected to different levels of anthropogenic disturbances. In this study, water samples were collected from twelve freshwater lakes located around the city of Nanjing, China. Both Illumina MiSeq sequencing and multivariate statistical analysis were employed to determine the bacterioplankton community composition and its relation to environmental variables. The results indicated that tourism disturbances (mostly sewage discharge and tourist activities) altered the community structure of both abundant and rare bacterioplankton by changing water physicochemical characteristics. Alpha diversity of both abundant and rare taxa did not differ among different anthropogenic disturbance lakes (p > 0.05). Rare bacterial taxa possessed higher alpha diversity than abundant taxa, though rare taxa occupied a tiny portion of abundance (4.5%). Redundancy analysis demonstrated that dissolved organic carbon (DOC) was the most significant correlation variable for constraining the variation of abundant taxa, whereas total phosphorus (TP), ammonium nitrogen (NH4+-N), and chlorophyll-a (Chl-a) were the most dominant environmental factors constraining the rare taxa, indicating abundant and rare taxa may have different ecological niches.

Highlights

Bacterioplankton, which are ubiquitous and numerous in lake ecosystems, play prominent roles in regenerating and mobilizing nutrients within freshwater food webs and have profound effects on biogeochemical cycling and water quality [1]
We examined the diversity and composition of abundant and rare taxa in freshwater lakes subjected to different levels of tourist disturbances, coupled with physicochemical analyses, high-throughput sequencing technology, bioinformatics analyses, and multivariate statistical methods
Our work reveals the diversity and composition of abundant and rare bacterial taxa derived from freshwater lakes in response to different levels of tourism disturbances

Summary

Introduction

Bacterioplankton, which are ubiquitous and numerous in lake ecosystems, play prominent roles in regenerating and mobilizing nutrients within freshwater food webs and have profound effects on biogeochemical cycling and water quality [1]. Some studies have reported that most lakes in China are in a degraded state and water quality has become a great concern due to industrialization and urbanization [15,16]. This is true for lakes situated in urban areas with high human density, such as the cities of. Wuhan and Nanjing [17], as they are more exposed to pollution due to industrial effluent and domestic wastewater [18] These remind us that microbial communities may be affected by environmental change from anthropogenic perturbations, which, in turn, alter biogeochemical processes in these water bodies [19]

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Conclusion