The impact of algal blooms on promoting in-situ N2O emissions: A case in Zhanjiang bay, China

Shangjun Cai; Qibin Lao; Chunqing Chen; Qingmei Zhu; Fajin Chen

doi:10.1016/j.jenvman.2024.120935

The impact of algal blooms on promoting in-situ N₂O emissions: A case in Zhanjiang bay, China

J Environ Manage. 2024 May:358:120935. doi: 10.1016/j.jenvman.2024.120935. Epub 2024 Apr 21.

Authors

Shangjun Cai¹, Qibin Lao¹, Chunqing Chen¹, Qingmei Zhu², Fajin Chen³

Affiliations

¹ College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, China; School of Chemistry and Environment, Guangdong Ocean University, Zhanjiang, 524088, China.
² College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, China; School of Chemistry and Environment, Guangdong Ocean University, Zhanjiang, 524088, China; Key Laboratory for Coastal Ocean Variation and Disaster Prediction, Guangdong Ocean University, Zhanjiang, 524088, China; Key Laboratory of Climate, Resources and Environment in Continental Shelf Sea and Deep Sea of Department of Education of Guangdong Province, Guangdong Ocean University, Zhanjiang, 524088, China.
³ College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, 524088, China; School of Chemistry and Environment, Guangdong Ocean University, Zhanjiang, 524088, China; Key Laboratory for Coastal Ocean Variation and Disaster Prediction, Guangdong Ocean University, Zhanjiang, 524088, China; Key Laboratory of Climate, Resources and Environment in Continental Shelf Sea and Deep Sea of Department of Education of Guangdong Province, Guangdong Ocean University, Zhanjiang, 524088, China. Electronic address: fjchen@gdou.edu.cn.

PMID: 38648725
DOI: 10.1016/j.jenvman.2024.120935

Abstract

Under the influence of many factors, such as climate change, anthropogenic eutrophication, and the development of aquaculture, the area and frequency of algal blooms have showed an increasing trend worldwide, which has become a challenging issue at present. However, the coupled relationship between nitrous oxide (N₂O) and algal blooms and the underlying mechanisms remain unclear. To address this issue, ¹⁵N isotope cultures and quantitative polymerase chain reaction (qPCR) experiments were conducted in Zhanjiang Bay during algal and non-algal bloom periods. The results showed that denitrification and nitrification-denitrification were the two processes responsible for the in-situ production of N₂O during algal and non-algal bloom periods. Stable isotope rate cultivation experiments indicated that denitrification and nitrification-denitrification were promoted in the water during the algal bloom period. The in-situ production of N₂O during the algal bloom period was three-fold that during the non-algal bloom period. This may be because fresh particulate organic matter (POM) from the organisms responsible for the algal bloom provides the necessary anaerobic and hypoxic environment for denitrification and nitrification-denitrification in the degradation environment. Additionally, a positive linear correlation between N₂O concentrations and ammonia-oxidizing bacteria (AOB) and denitrifying bacteria (nirK and nirS) also supported the significant denitrification and nitrification-denitrification occurring in the water during the algal bloom period. However, the algal bloom changed the main process for the in-situ production of N₂O, wherein it shifted from denitrification during the non-algal bloom period to nitrification-denitrification during the algal bloom period. The results of our study will improve our understanding of the processes responsible for the in-situ production of N₂O during the algal bloom period, and can help formulate effective policies to mitigate N₂O emissions in the bay.

Keywords: (15)N isotope; Algal bloom; Nitrification-denitrification; Nitrous oxide emission; Zhanjiang bay.

Publication types

Review

MeSH terms

Bays
China
Denitrification
Eutrophication*
Nitrification*
Nitrous Oxide* / analysis
Nitrous Oxide* / metabolism

Substances

Nitrous Oxide