Disentangling the seasonal co-occurrence patterns and ecological stochasticity of planktonic and benthic bacterial communities within multiple lakes

Congcong Jiao; Dayong Zhao; Jin Zeng; Lin Guo; Zhongbo Yu

doi:10.1016/j.scitotenv.2020.140010

Disentangling the seasonal co-occurrence patterns and ecological stochasticity of planktonic and benthic bacterial communities within multiple lakes

Sci Total Environ. 2020 Oct 20:740:140010. doi: 10.1016/j.scitotenv.2020.140010. Epub 2020 Jun 6.

Authors

Congcong Jiao¹, Dayong Zhao², Jin Zeng³, Lin Guo⁴, Zhongbo Yu²

Affiliations

¹ Joint International Research Laboratory of Global Change and Water Cycle, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China; State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
² Joint International Research Laboratory of Global Change and Water Cycle, State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Hohai University, Nanjing 210098, China.
³ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: jzeng@niglas.ac.cn.
⁴ Department of Biological and Environmental Sciences, Texas A&M University, Commerce, TX 76129, USA.

PMID: 32563874
DOI: 10.1016/j.scitotenv.2020.140010

Abstract

Both the planktonic bacterial community (PBC) and benthic bacterial community (BBC) are important for biogeochemical processes in freshwater lakes. Despite their ecological significance, little is known about their seasonal co-occurrence patterns and the ecological processes that drive them. In this study, we aimed to investigate the ecological associations among bacterial taxa and assembly processes of PBC and BBC in different seasons. We used 16S rRNA gene high-throughput sequencing of a total of 150 water and sediment samples collected from multiple lakes distributed in an urban region of China during winter and summer. Our results revealed that PBC showed stronger seasonal variations in co-occurrence patterns than BBC, suggesting that BBC had greater temporal stability than PBC. Winter PBC network was characterized by higher connectivity and complexity, and thereby the formation of a highly stable community structure; whereas lower connectivity arising from the presence of fewer predicted keystone taxa (hubs and connectors in a network) was destabilizing to summer PBC network. In addition, the phylum Firmicutes identified as a putative keystone taxon of PBC in both seasons played a non-negligible role in maintaining network structure which may result from strong functional associations with other bacterioplankton. Temperature and pH were the best explanatory factors predicting the seasonal co-occurrence patterns of PBC and BBC, respectively. Normalized stochasticity ratio based on null-model analysis indicated that deterministic processes overwhelmed stochastic processes in governing the assembly of PBC and BBC in both seasons. However, we observed a greater influence of ecological stochasticity on BBC assembly than PBC assembly in both seasons. Taken together, these findings provide insights into understanding the impacts of habitat heterogeneity and seasonal variability on microbial assemblage patterns in lake ecosystems.

Keywords: Community assembly processes; Freshwater lakes; Habitat heterogeneity; Keystone taxa; Network analysis; Normalized stochasticity ratio.

MeSH terms

China
Lakes*
Microbiota*
Plankton
RNA, Ribosomal, 16S
Seasons

Substances

RNA, Ribosomal, 16S