Well-designed composite catalysts are of increasing concern due to their improved performance compared to individual components. Herein, we designed and synthesized an Fe₃O₄@MoS₂ composite via a simple hydrothermal method. As for the resultant composite, the MoS₂ nanolayers presented a novel piezo-catalytic effect, while the Fe₃O₄ core provided a magnetic separation property. The structure and properties of Fe₃O₄@MoS₂ were determined by relevant experiments. It was found that Fe₃O₄@MoS₂ exhibited enhanced piezo-catalytic degradation of rhodamine B and good magnetic recovery/recycling features. The k_obs for rhodamine B degradation over Fe₃O₄@MoS₂ was 0.019 min⁻¹—a little longer than that over MoS₂ (0.013 min⁻¹). Moreover, Fe₃O₄@MoS₂ also showed a favorable ability to adsorb rhodamine B in solution, with a saturation adsorption of 26.8 mg/g. Further studies revealed that piezo-electrons, holes, and superoxide anions were key species in the piezo-catalytic degradation of rhodamine B. Notably, the step where oxygen trapped electrons to produce superoxide anions had a significant impact on the degradation of the dye. This work, not limited to the development of a high-performance MoS₂-based piezo-catalyst, is expected to provide new insights into the working mechanisms and process profiles of composite piezo-catalysts.

Mapping high-spatial-resolution surface water bodies in urban and suburban areas is crucial in understanding the spatial distribution of surface water. Although Sentinel-2 images are popular in mapping water bodies, they are impacted by the mixed-pixel problem. Sub-pixel mapping can predict finer-spatial-resolution maps from the input remote sensing image and reduce the mixed-pixel problem to a great extent. This study proposes a sub-pixel surface water mapping method based on morphological dilation and erosion operations and the Markov random field (DE_MRF) to predict a 2 m resolution surface water map for heterogeneous regions from Sentinel-2 imagery. DE_MRF first segments the normalized difference water index image to extract water pixels and then detects the mixed pixels by using combined morphological dilation and erosion operations. For the mixed pixels, DE_MRF considers the intra-pixel spectral variability by extracting multiple water endmembers and multiple land endmembers within a local window to generate the water fraction images through spectral unmixing. DE_MRF was evaluated in the Jinshui Basin, China. The results suggested that DE_MRF generated a lower commission error rate for water pixels compared to the comparison methods. Because DE_MRF considers the intra-class spectral variabilities in the unmixing, it is better in mapping sub-pixel water distribution in heterogeneous regions where different water bodies with distinct spectral reflectance are present.

Mycosporine-like amino acids (MAAs) are widespread in various microbes and protect them against harsh environments. Here, four different Aphanizomenon species were isolated from severely eutrophic waterbodies, Lake Dianchi and the Guanqiao fishpond. Morphological characters and molecular phylogenetic analysis verified that the CHAB5919, 5921, and 5926 strains belonged to the Aphanizomenon flos-aquae clade while Guanqiao01 belonged to the Aphanizomenon gracile clade. Full wavelength scanning proved that there was obvious maximal absorption at 334 nm through purified methanol extraction, and these substances were further analyzed by HPLC and UPLC-MS-MS. The results showed that two kinds of MAAs were discovered in the cultured Aphanizomenon strains. One molecular weight was 333.28 and the other was 347.25, and the daughter fragment patterns were in accordance with the previously articles reported shinorine and porphyra-334 ion characters. The concentration of the MAAs was calibrated from semi-prepared MAAs standards from dry cells of Microcystis aeruginosa PCC7806 algal powder, and the purity of shinorine and porphyra-334 were 90.2% and 85.4%, respectively. The average concentrations of shinorine and porphyra-334 were 0.307–0.385 µg/mg and 0.111–0.136 µg/mg in Aphanizomenon flos-aquae species, respectively. And there was only one kind of MAAs (shinorine) in Aphanizomenon gracile species.,with a content of 0.003–0.049 µg/mg dry weight among all Aphanizomenon gracile strains. The shinorine concentration in Aphanizomenon flos-aquae was higher than that in Aphanizomenon gracile strains. The total MAAs production can be ranked as Aphanizomenon flos-aquae > Aphanizomenon gracile.

Cyanobacterial blooms, which are increasingly exacerbated by eutrophication and climate change, pose threats to ecosystems and public health. This paper systematically reviews recent advances in microbial intervention strategies for controlling cyanobacterial blooms. Current approaches primarily comprise direct lysis methods, indirect suppression methods, and integrated strategies. Direct algicide methods rapidly lyse cyanobacterial cells and degrade toxins, although their application is constrained by environmental sensitivity and host specificity. Indirect approaches offer sustainable preventive strategies by inhibiting cyanobacterial growth, yet require careful environmental management. Integrated methods combine microbial strategies with other technologies, enhancing both the efficiency and ecological safety of managing cyanobacterial blooms. While microbial strategies demonstrate significant potential, practical implementation faces challenges, including environmental adaptability, ecological safety, and regulatory frameworks. Future research should focus on integrating synthetic biology, intelligent delivery systems, and multi-omics technologies to achieve more effective and environmentally friendly management of cyanobacterial blooms.