Effect of simulated tidal cycle on DOM, nitrogen and phosphorus release from sediment in Dagu River-Jiaozhou Bay estuary

Xinjuan Wang; Fanlong Kong; Yue Li; Qinghao Li; Chunrong Wang; Junlong Zhang; Min Xi

doi:10.1016/j.scitotenv.2021.147158

Effect of simulated tidal cycle on DOM, nitrogen and phosphorus release from sediment in Dagu River-Jiaozhou Bay estuary

Sci Total Environ. 2021 Aug 20:783:147158. doi: 10.1016/j.scitotenv.2021.147158. Epub 2021 Apr 18.

Authors

Xinjuan Wang¹, Fanlong Kong¹, Yue Li¹, Qinghao Li¹, Chunrong Wang², Junlong Zhang³, Min Xi⁴

Affiliations

¹ College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China.
² College of Mathematics and Statistics, Qingdao University, Qingdao 266071, China.
³ College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China. Electronic address: zhangjunlong1021@163.com.
⁴ College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China. Electronic address: ximin@qdu.edu.cn.

PMID: 34088113
DOI: 10.1016/j.scitotenv.2021.147158

Abstract

Tide drives salt mixing processes, erosion, deposition, and nutrient circulation in sediments, which is critical to the estuarine systems. This study aims to investigate the effects of tidal cycle intensity on sediment dissolved organic matter (DOM), nitrogen and phosphorus release. In this study, the effects of tide are investigated by simulating different intensity of tidal disturbance with tidal simulator devices. The microbial community changes under different tidal cycle are disclosed to explain the mechanism of nutrient release. In addition, the short-term release of nitrogen and phosphorus under simulated tidal cycle is predicted by stepwise regression method. Results show that the higher the tidal cycle intensity, the stronger the DOM mineralization in sediments and diffusion into overlying water, leading to a sustained increase of fluorescence intensity in DOM. Besides, the tidal disturbance promotes the NH₄⁺-N and NO₃^--N release and the tidal disturbance is helpful for ammonification. While the greater the tidal intensity, the lower the NO₃^--N release. Content of released total phosphorus (TP) maintains at a low level and fluctuates over time under different simulated tidal intensity. In addition, tidal cycle greatly changes the microbial richness and diversity. Gammaproteobactere has the ability of denitrification and can reduce nitrate to nitrite. Besides, tidal environment greatly affects the abundance of Marinobacter which can enhance the N, P, and C migration transformation ability. The research on microbial community further explains the mechanism of nutrient release. The model of nitrogen and phosphorus release contributes to providing basic data for predicting the short-term release of nutrients under different simulated tidal intensity.

Keywords: DOM; Nitrogen; Phosphorus; Sediment; Simulated tidal cycle; Stepwise regression method.