Microplastics inhibit biofloc formation and alter microbial community composition and nitrogen transformation function in aquaculture

Liu-Jiang Meng; Xin Hu; Bin Wen; Yuan-Hao Liu; Guo-Zhi Luo; Jian-Zhong Gao; Zai-Zhong Chen

doi:10.1016/j.scitotenv.2022.161362

Microplastics inhibit biofloc formation and alter microbial community composition and nitrogen transformation function in aquaculture

Sci Total Environ. 2023 Mar 25:866:161362. doi: 10.1016/j.scitotenv.2022.161362. Epub 2023 Jan 5.

Authors

Liu-Jiang Meng¹, Xin Hu², Bin Wen³, Yuan-Hao Liu⁴, Guo-Zhi Luo⁵, Jian-Zhong Gao⁴, Zai-Zhong Chen⁶

Affiliations

¹ Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; University of Chinese Academy of Sciences, Beijing 100049, China.
² Shanghai Engineering Research Center of Aquaculture, Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture Animals, Shanghai Ocean University, Shanghai 201306, China.
³ Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture Animals, Shanghai Ocean University, Shanghai 201306, China. Electronic address: bwen@shou.edu.cn.
⁴ Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture Animals, Shanghai Ocean University, Shanghai 201306, China.
⁵ National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture Animals, Shanghai Ocean University, Shanghai 201306, China.
⁶ Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture and Rural Affairs, Shanghai Ocean University, Shanghai 201306, China; Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Ministry of Education, Shanghai Ocean University, Shanghai 201306, China; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China; Shanghai Engineering Research Center of Aquaculture, Shanghai Collaborative Innovation Center for Cultivating Elite Breeds and Green-culture of Aquaculture Animals, Shanghai Ocean University, Shanghai 201306, China. Electronic address: chenzz@shou.edu.cn.

PMID: 36610618
DOI: 10.1016/j.scitotenv.2022.161362

Abstract

Biofloc technology, extensively used in intensive aquaculture systems, can prompt the formation of microbial aggregates. Microplastics (MPs) are detected abundantly in aquaculture waters. This study explored the effects of MPs on biofloc formation, microbial community composition and nitrogen transformation function in simulated biofloc aquaculture production systems. The formation process and settling performance of bioflocs were examined. High-throughput sequencing of 16S and 18S rRNA genes was used to investigate the microbial community compositions of bioflocs. Nitrogen dynamics were monitored and further explained from functional genes and microorganisms related to nitrogen transformation by metagenome sequencing. We found that the aggregates consisting of bioflocs and MPs were formed and the systems with MPs had relatively weak settling performance. No significant differences in bacterial diversity (p > 0.05) but significant differences in eukaryotic diversity (p < 0.05) were found between systems without and with MPs. Significant separations in the microbial communities of prokaryotes (p = 0.01) and eukaryotes (p = 0.01) between systems without and with MPs were observed. The peak concentration of nitrite nitrogen (NO₂^--N) in systems with MPs was lower than that in systems without MPs (p_{Control/MPs Low} = 0.02 and p_{Control/MPs High} = 0.03), probably due to the low abundance of hao and affiliated Alphaproteobacteria_bacterium_HGW-Alphaproteobacteria-1 and Alphaproteobacteria_bacterium, but the high abundance of nxrA and affiliated Alphaproteobacteria_bacterium_SYSU_XM001 and Hydrogenophaga_pseudoflava that related to nitrification. The low concentration of NO₂^--N in systems with MPs suggested that the presence of MPs might inhibit ammonia oxidation but promote nitrite oxidation by altering the microbial community structure and function. These results indicated that aggregates consisting of bioflocs and MPs could be formed in aquaculture water, and thus, inhibiting their settlement and altering nitrogen transformation function by affecting the microbial community composition.

Keywords: Biofloc technology; Microbial community; Microplastic; Nitrogen transformation.

MeSH terms

Aquaculture / methods
Microbiota*
Microplastics*
Nitrogen
Nitrogen Dioxide
Plastics

Substances

Microplastics
Plastics
Nitrogen
Nitrogen Dioxide