Physical and Chemical Conditions Affecting Spirulina Blooms in a Natural Waterbody in Rajshahi, Bangladesh

Purpose: Spirulina, an organic source of protein, antioxidants, and vitamins, is consumable for humans, poultry, and fisheries. Growing awareness regarding organic and vegan diets has created a spotlight on the commercial production of Spirulina, even in Bangladesh. In Bangladesh, major pharmaceutical and feed companies already produce Spirulina products, but the raw materials (i.e. Spirulina) are imported from different countries. Entrepreneurs and investors are not interested in taking the risk of financing raw material bulk production. Even there is a knowledge gap that Spirulina can grow naturally in Rajshahi. Methodology: The methodology used was a systematic literature review, which identified the knowledge gap. After that, a search was carried out to find Spirulina growing habitats. A waterbody with a Spirulina bloom was detected. Prescribed methods measured weekly data of physical-chemical conditions and cell density of Spirulina. Findings: The first report of Spirulina, a cyanobacterial bloom, was reported from a waterbody in Rajshahi, Bangladesh in this study. During the study period, the abundance of Spirulina varied from 4.65 x 107 -5.7 x107 cells/L. The major physical-chemical factors of water during bloom were found to vary as air and water temperature 19- 25°C and 18- 20.67°C, pH 8.00 -11.00, transparency 5-20 cm, dissolved oxygen 1.67 – 9.42 mg/l, alkalinity 28.20- 170mg/l, hardness 28.20 – 188mg/l and BOD 3.00 – 5.97mg/l. The water body in the urban area receives organic load from households nearby regularly. Unique Contribution to Theory, Policy and Practice: The data and results support that Rajshahi's climate is suitable for producing Spirulina; thus, its commercialization is possible in this region of Bangladesh. The findings will inspire investors and entrepreneurs to invest in the Mass production of Spirulina for commercialization in northern Bangladesh. Even policymakers may formulate a long-term production strategy for Spirulina production to fulfil the local and international market demand.