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Effective management of Harmful Algal Blooms (HABs) requires understanding factors influencing their occurrence. This study explores these dynamics in the Pengxi River, a tributary of the Three Gorges Reservoir, focusing on nutrient stratification and algal blooms. We hypothesized that nutrient levels in eutrophic waters with stable stratification correlate with HAB magnitude and that disruption of stratification triggers blooms due to nutrient shifts. A 38-day sampling campaign in Gaoyang Lake (April 16–May 23, 2022) revealed that consistent weather between April 26 and May 16 led to a surface density layer, restricting nutrient transfer and causing a bloom with 173.0 μg L−1 Chl-a on May 1. After a heavy rain on May 18, a peak bloom on May 20, dominated by Ceratium hirundinella , showed 533 μg L−1 Chl-a. There was a significant negative correlation between Cyanobacteria and C. hirundinella biomasses (r = −0.296, P < 0.01), highlighting nutrient availability and physical stability's roles in regulating HABs. [Display omitted] • Surface Density Layers (SDLs) influence nutrient flux and HABs. • Heavy rainfall disrupts thermal stratification, leading to nutrient mixing and algal blooms. • Nutrient levels impact phytoplankton competition and community composition. [ABSTRACT FROM AUTHOR]

Abstract A two-dimensional numerical model for a photoelectrochemical (PEC) cell.for CO 2 utilization and fuel production was developed using COMSOL Multiphysics and validated with published experimental data. The model couples computational fluid dynamics with electrochemical kinetics to account for the complex interactions inside the PEC driven by light absorption operating at the Shockyley-Queisser limit. Charge and species conservation, fluid flow and electrochemical characteristics are studied. The flow rate of CO 2 is found to be the factor affecting the cell performance. Parametric study for operating conditions is necessary in future work. [ABSTRACT FROM AUTHOR]

[Display omitted] • Comparative evalution of CuO powders, films and coatings for CO 2 photocatalytic reduction. • CuO showed selectivity to only produce CH 4 in the CO 2 photocatalytic reduction. • Active sites favored the formation of mono and bidentate bonds between CO 2 and CuO. The use of CuO-based photocatalysts for CO 2 photoreduction has been extensively reported in the literature. However, the comparison of the photocatalytic activity and selectivity from the published results becomes difficult due to different experimental conditions (i.e. , synthesis method, configuration of photocatalyst, flow rate of gas, water content, light intensity) and reactor geometry employed. Hence, in this work different conformations of CuO-based photocatalyst, namely powder (i.e. , synthesized using precipitation, sonochemical and hydrothermal-microwave treatment), coating on glass fiber mesh, and thin film, were tested using the same photoreactor and experimental conditions. All CuO photocatalysts exhibited 100 % product selectivity towards CH 4 over CO and the CuO coating on the glass fiber mesh exhibited the highest production of CH 4 (56.3 μmol g cat −1 h−1). The morphology, particle size, particle dispersity, and presence of impurities/defects within the CuO photocatalysts had a significant effect on photocatalytic activity. A numerical model, which was built using COMSOL, revealed that the experimental data obtained in this simulated photocatalytic activity study fitted well, however, further optimization was needed. [ABSTRACT FROM AUTHOR]