Glancing of Bima Bay's algae bloom from environmental perspective.

Algae bloom is an indicator of a polluted marine and freshwater ecosystem. It is universally initiated by eutrophication and amplified by high water temperature and light in an euphotic zone. A descriptive research was conducted to review climatic factors attributed to current algae bloom (Bacillariophyta) in the Bima Bay, West Nusa Tenggara, eastern Indonesia. Main variables in this study were sea water temperature (SWT), air temperature (Ta), direct normal solar irradiation (DNI), total suspended solids (TTS) and tide variation. All data were secondary data related to the Bima Bay. Results showed that before bloom event, SWT inside the bay was commonly lower than outside. In normal condition, SWT peaked at 29.9 ^oC in November. However, during bloom event in 2022, the peak had shifted to mid-season in March and April when it was steady high at 29.7^oC and 30.3^oC respectively. It had been extremely high of 31^oC on 17^th to 21^st April 2022 which was proceeded by blooming algae on April, 26^th 2022. DNI usually reached its average level at 17.9 MJm⁻²day⁻¹ in April. TSS steadily increased by 0.92 mgL⁻¹year⁻¹ since 1990. It had passed the average level of 24.6 mgL⁻¹ since 2004, and reached the highest level of 66.7 mgL⁻¹ in 2021. This was beyond the threshold level (20 mgL⁻¹) for marine ecosystem. In conclusion, SWT ranged from 29.7^oC – 30,3^oC, light intensity of 17.9 MJm⁻²day⁻¹, euphotic zone of 3-10 m deep, and tide height of 1.3 m were favorable conditions for ma-rine Bacillariophyte (Diatoms) in the Bima Bay in April 2022. [ABSTRACT FROM AUTHOR]