Phytoplankton and Bacterial Community Structure in Two Chinese Lakes of Different Trophic Status.

Cui Feng,Xiangjiang Liu,Mengqi Han,Jingyi Jia,Bin Huo,Dapeng Li,Chen Wang,Chenchen Dong

doi:10.3390/microorganisms7120621

Cui Feng, Xiangjiang Liu + Show 6 more

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https://doi.org/10.3390/microorganisms7120621

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Journal: Microorganisms	Publication Date: Nov 27, 2019
Citations: 16	License type: CC BY 4.0

Affiliation: Huazhong Agricultural University

Abstract

Phytoplankton are the primary producers at the basis of aquatic food webs, and bacteria play an important role in energy flow and biochemical cycling in aquatic ecosystems. In this study, both the bacterial and phytoplankton communities were examined in the oligotrophic Lake Basomtso and the eutrophic Lake South (China). The results of this study showed that the phytoplankton density and diversity in the eutrophic lake were higher than those in the oligotrophic lake. Furthermore, Chlorophyta (68%) and Cryptophyta (24%) were the dominant groups in the eutrophic lake, while Bacillariophyta (95%) dominated in the oligotrophic lake. The bacterial communities in the waters and sediments of the two lakes were mainly composed of Proteobacteria (mean of 32%), Actinobacteria (mean of 25%), Bacteroidetes (mean of 12%), and Chloroflexi (mean of 6%). Comparative analysis showed that the abundance of bacteria in the eutrophic lake was higher than that in the oligotrophic lake (p < 0.05), but the bacterial diversity in the oligotrophic lake was higher than that in the eutrophic lake (p < 0.05). Finally, the bacterial abundance and diversity in the sediments of the two lakes were higher than those in the water samples (p < 0.05), and the Latescibacteria and Nitrospinae groups were identified only in the sediments. These results suggest that both the phytoplankton and bacterial communities differed considerably between the oligotrophic lake and the eutrophic lake.

Highlights

Microorganisms are both the producers and decomposers of organic matter in aquatic ecosystems and play an important role in regulating the circulation of biogenic elements such as carbon, nitrogen, phosphorus, and sulfur in lakes [1,2]
As an important part of the microbial community, are mainly responsible for the mineralization and recycling of organic matter, while the recycling of dissolved organic carbon (DOC) in lakes is mainly fulfilled by heterotrophic bacteria [3,4,5]
The dissolved oxygen (DO) was slightly lower in oligotrophic Lake Basomtso than in eutrophic Lake South

Summary

Introduction

Microorganisms are both the producers and decomposers of organic matter in aquatic ecosystems and play an important role in regulating the circulation of biogenic elements such as carbon, nitrogen, phosphorus, and sulfur in lakes [1,2]. Interactions between phytoplankton and bacteria have been proposed to influence bacterial community dynamics [7,8,9]. Bacteria rapidly utilize exudates released by phytoplankton (e.g., sugars, amino acids), as well as detritus following algal cell death [7,10]. In addition to providing a source of organic matter, phytoplankton can provide a habitat for endophytic bacteria living within algae cells and epiphytic bacteria that live in the phycosphere surrounding algal cells [11,12]. Phytoplankton could display a negative effect on the bacterial community through nutrient competition and antibiotic release [13]

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