Stimulation of high-concentration dissolved nitrogen and reactive phosphorus in Lake Taihu sediments on the initiation and maintenance of cyanobacterial blooms

Xianfang Fan; Shuaishuai Gao; Yi Zhang; Boqiang Qin; Hai Xu; Shiming Ding

doi:10.1016/j.scitotenv.2022.158088

Stimulation of high-concentration dissolved nitrogen and reactive phosphorus in Lake Taihu sediments on the initiation and maintenance of cyanobacterial blooms

Sci Total Environ. 2022 Dec 10;851(Pt 2):158088. doi: 10.1016/j.scitotenv.2022.158088. Epub 2022 Aug 17.

Authors

Xianfang Fan¹, Shuaishuai Gao², Yi Zhang³, Boqiang Qin¹, Hai Xu¹, Shiming Ding⁴

Affiliations

¹ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
² State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Hunan Institute of Microbiology, Changsha 410009, China.
³ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Water Conservancy Development Research Center of Taihu Basin Authority Ministry of Water Resource, Shanghai 200434, China.
⁴ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: smding@niglas.ac.cn.

PMID: 35987223
DOI: 10.1016/j.scitotenv.2022.158088

Abstract

The spatio-temporal variation of dissolved inorganic nitrogen (DIN: NH₄⁺-N, NO₂^--N, and NO₃^--N) and dissolved reactive phosphorus (DRP) in Meiliang Bay of Lake Taihu sediments and their potential effects on the cyanobacterial blooms were studied. Monthly sampling was performed using high-resolution dialysis sampling devices (HR-Peeper) and two important results were observed in April (the initiation period of cyanobacterial bloom) and June-August (the maintenance period of cyanobacterial blooms). In April, high concentrations of dissolved NO₂^--N and NO₃^--N, probably caused by the groundwater influx, were observed in deep anoxic sediments (below 110 mm). NO₂^--N and NO₃^--N are good electron acceptors for the mineralization of organic P under anaerobic conditions and should lead to an increase in DRP concentrations in sediments, DRP released from sediments thus further stimulating the cyanobacterial growth and the outbreak of severe cyanobacterial blooms in May due to the extremely low concentrations of DRP in the water body. From June to August, high concentrations of NO₂^--N, NO₃^--N, and DRP were observed in the surface sediment, which was caused by the release of NH₄⁺-N from the mineralization of cyanobacterial debris. This should play an important role in maintaining cyanobacterial growth, especially in stimulating the occurrence of cyanobacterial blooms during September, when N and P were co-limited. This study revealed high-concentration DIN and DRP in Lake Taihu sediments potentially stimulated the initiation and maintenance of cyanobacterial blooms.

Keywords: Cyanobacterial blooms; Dissolved inorganic nitrogen and reactive phosphorus; Eutrophic sediments; HR-Peeper; Lake Taihu.

MeSH terms

China
Cyanobacteria*
Eutrophication
Lakes*
Nitrogen / analysis
Nitrogen Dioxide
Phosphorus / analysis
Water

Substances

Phosphorus
Nitrogen
Nitrogen Dioxide
Water