[en] Highlights: • Simulated devices are built to simulate the tidal cycle. • Tidal cycle has significant effect on the release of DOM, N and P. • Tidal cycle changes the microbial richness and diversity. • Microbial diversity explains the mechanism of nutrient release. • A model is introduced to predict the short-term release of N and P. 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.

[en] Graphical abstract: Wurtzite CdS and ZnS urchinlike architectures were synthesized by a facile mixed solvothermal process. Highlights: → CdS and ZnS nanostructures with complex urchinlike morphology were synthesized by a facile solvothermal approach in a mixed solvent made of ethylenediamine, ethanolamine and distilled water. → These urchinlike architectures were composed of arranged nanorods with wurtzite structure. → The PL spectrum of the CdS urchinlike architecture displays a very strong red emission band centered at about 706 nm. - Abstract: CdS and ZnS nanostructures with complex urchinlike morphology were synthesized by a facile solvothermal approach in a mixed solvent made of ethylenediamine, ethanolamine and distilled water. No extra capping agent was used in the process. The structure, morphologies and optical properties of these nanostructures were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The as-synthesized urchinlike architectures were composed of nanorods with wurtzite structure. The preferred growth direction of nanorods was found to be the [0 0 1] direction. The PL spectrum of CdS nanostructures exhibited a highly intense red emission band centered at about 706 nm. On the basis of the experimental results, a possible growth process has been discussed for the formation of the CdS and ZnS urchinlike structures.

[en] Mn-doped ZnS sea urchin-like architectures were fabricated by a one-pot solvothermal route in a ternary solution made of ethylenediamine, ethanolamine and distilled water. The as-prepared products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and photoluminescence spectra (PL). It was demonstrated that the as-prepared sea urchin-like architectures with diameter of 0.5-1.5 μm were composed of nanorods, possessing a wurtzite structures. The preferred growth orientation of nanorods was found to be the [0 0 2] direction. The PL spectra of the Mn-doped ZnS sea urchin-like architectures show a strong orange emission at 587 nm, indicating the successful doping of Mn²⁺ ions into ZnS host. Ethanolamine played the role of oriented-assembly agent in the formation of sea urchin-like architectures. A possible growth mechanism was proposed to explain the formation of sea urchin-like architectures.