Effects of intensive oyster farming on nitrogen speciation in surface sediments from a typical subtropical mariculture bay

Lei Xie; Bin Yang; Jie Xu; Solomon Felix Dan; Zhiming Ning; Jiaodi Zhou; Zhenjun Kang; Dongliang Lu; Haifang Huang

doi:10.1016/j.scitotenv.2024.170092

Effects of intensive oyster farming on nitrogen speciation in surface sediments from a typical subtropical mariculture bay

Sci Total Environ. 2024 Mar 15:916:170092. doi: 10.1016/j.scitotenv.2024.170092. Epub 2024 Jan 19.

Authors

Lei Xie¹, Bin Yang², Jie Xu³, Solomon Felix Dan⁴, Zhiming Ning⁵, Jiaodi Zhou⁶, Zhenjun Kang⁴, Dongliang Lu⁴, Haifang Huang⁴

Affiliations

¹ Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China.
² Jiangsu Key Laboratory of Marine Bioresources and Environment, Jiangsu Ocean University, Lianyungang 222005, China; Guangxi Key Laboratory of Marine Environment Change and Disaster in Beibu Gulf, Beibu Gulf University, Qinzhou 535011, China. Electronic address: binyang@jou.edu.cn.
³ Center for Regional Ocean, Department of Ocean Science and Technology, Faculty of Science and Technology, University of Macau, Taipa, Macau.
⁴ Guangxi Key Laboratory of Marine Environment Change and Disaster in Beibu Gulf, Beibu Gulf University, Qinzhou 535011, China.
⁵ Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Guangxi University, Nanning 530004, China.
⁶ Guangxi Key Laboratory of Marine Environment Change and Disaster in Beibu Gulf, Beibu Gulf University, Qinzhou 535011, China; Guangxi Laboratory on the Study of Coral Reefs in the South China Sea, Guangxi University, Nanning 530004, China.

PMID: 38246374
DOI: 10.1016/j.scitotenv.2024.170092

Abstract

The spatial-temporal distributions of various nitrogen (N) species in surface sediments were examined in a typical subtropical mariculture bay (Maowei Sea) in the northern Beibu Gulf to assess the impact of intensive oyster culture activities on sedimentary N speciation. The results indicated that the mean contents of total nitrogen (TN), extractable (labile) nitrogen (LN) and residual nitrogen (RN) in the surface sediments were 33.3 ± 15.5 μmol g^-1, 13.8 ± 1.3 μmol g^-1 and 19.5 ± 15.0 μmol g^-1, respectively, which lacked significant seasonal variability (P > 0.05). Four forms of LN, namely ion extractable form (IEF-N), weak acid extractable form (WAEF-N), strong alkali extractable form (SAEF-N) and strong oxidant extractable form (SOEF-N) were identified based on sequential extraction. SOEF-N was the dominant form of LN, accounting for 67.8 ± 2.5 % and 63.7 ± 5.9 % in summer and winter, respectively. Spatially, the contents of sedimentary TN, LN, RN, WAEF-N and SOEF-N in intensive mariculture areas (IMA) were significantly higher than those in non-intensive mariculture areas (NIMA) during summer (P < 0.05). Stable nitrogen isotope (δ¹⁵N) mixing model revealed that shellfish biodeposition was the predominant source of sedimentary TN in IMA with a contribution of 67.8 ± 23.0 %, approximately 5.4 times that of NIMA (12.6 ± 3.3 %). Significant positive correlations (P < 0.05) were observed between most forms of N species (WAEF-N, SOEF-N, LN and RN) and shellfish-biodeposited N in the surface sediments during summer, indicating that intensive oyster farming greatly enhanced sedimentary TN accumulation.

Keywords: Maowei Sea; Nitrogen speciation; Oyster farming; Stable nitrogen isotope; Surface sediments.

MeSH terms

Agriculture
Animals
Bays
China
Environmental Monitoring
Geologic Sediments
Nitrogen / analysis
Ostreidae*
Water Pollutants, Chemical* / analysis

Substances

Nitrogen
Water Pollutants, Chemical