Light is an important factor that affects cyanobacterial growth and changes in light can influence their growth and physiology. However, an information gap exists regarding light-induced oxidative stress and the species-specific behavior of cyanobacteria under various light levels. This study was conducted to evaluate the comparative effects of different light intensities on the growth and stress responses of two cyanobacteria species, Pseudanabaena galeata (strain NIES 512) and Microcystis aeruginosa (strain NIES 111), after periods of two and eight days. The cyanobacterial cultures were grown under the following different light intensities: 0, 10, 30, 50, 100, 300, and 600 μmol m⁻² s⁻¹. The optical density (OD₇₃₀), chlorophyll a (Chl-a) content, protein content, H₂O₂ content, and the antioxidative enzyme activities of catalase (CAT) and peroxidase (POD) were measured separately in each cyanobacteria species. P. galeata was negatively affected by light intensities lower than 30 μmol m⁻² s⁻¹ and higher than 50 μmol m⁻² s⁻¹. A range of 30 to 50 μmol m⁻² s⁻¹ light was favorable for the growth of P. galeata, whereas M. aeruginosa had a higher tolerance for extreme light conditions. The favorable range for M. aeruginosa was 10 to 100 μmol m⁻² s⁻¹.

Microplastics (MPs) are an emerging pollutant in the aquatic environment, and this has gradually been recognized in the Asian region. This systematic review study, using the Scopus database, provides an insightful understanding of the spatial distribution of scientific studies on MPs in freshwater conducted across the Asian region, utilized sampling methods, and a detailed assessment of the effects of MPs on different biotic components in freshwater ecosystems, with special focus on its potential risks on human health. The results of this review indicate that research on microplastics in Asia has gained attention since 2014, with a significant increase in the number of studies in 2018, and the number of scientific studies quadrupled in 2021 compared to 2018. Results indicated that despite a significant amount of research has been conducted in many Asian countries, they were not distributed evenly, as multiple studies selected specific rivers and lakes. Additionally, around two-thirds of all the papers focused their studies in China, followed by India and South Korea. It was also found that most of the studies focused primarily on reporting the occurrence levels of MPs in freshwater systems, such as water and sediments, and aquatic organisms, with a lack of studies investigating the human intake of MPs and their potential risks to human health. Notably, comparing the results is a challenge because diverse sampling, separation, and identification methods were applied to estimate MPs. This review study suggests that further research on the dynamics and transport of microplastics in biota and humans is needed, as Asia is a major consumer of seafood products and contributes significantly to the generation of plastic litter in the marine environment. Moreover, this review study revealed that only a few studies extended their discussions to policies and governance aspects of MPs. This implies the need for further research on policy and governance frameworks to address this emerging water pollutant more holistically.

Humans and other organisms are adversely affected by cyanobacterial blooming. This study aims to investigate the long-term effects of light intensities and different temperatures on Phormidium ambiguum and Pseudanabaena foetida. Enough P. ambiguum and P. foetida cells were acclimated for 24 days at 30 °C, 20 °C, and 10 °C in separate incubators. The starting day sample was collected after 24 days of acclimatization, and a second sample was collected seven days later at light intensities of 10, 30, 50, 200, and 600 µmol m⁻² s⁻¹ for each temperature. The optical density (OD₇₃₀), hydrogen peroxide (H₂O₂) concentration, protein content, chlorophyll-a (Chl-a) concentration, and catalase (CAT) activity were measured. Light intensity changes soon after collection resulted in nearly identical starting day samples at each individual temperature. The H₂O₂ concentration and algal biomass increased until a light intensity of 200 µmol m⁻² s⁻¹ was reached and decreased afterward in each temperature for both species after seven days. In association with an increasing H₂O₂ concentration, the Chl-a concentration decreased after 50 µmol m⁻²s⁻¹ of light intensity, affecting the protein content. The algal biomass was significantly lower at 10 °C compared to 30 °C. The CAT activity increased proportionately with the H₂O₂ concentration and algal biomass. Therefore, water bodies in the field can be illuminated with long-term high light intensities in different temperatures to reduce algal biomass.