Distribution and abundance of microalgae based on coastal characteristic and ecology in Bone Bolango coastal region, Indonesia

The aim of this study was to map the distribution of microalgae and to measure their abundances in different areas of the Bone Bolango regency coastal region. Water samples were taken from 5 stations. A taxonomic identification of the microalgae was conducted, their abundances and spatial distribution was determined. The major groups of microalgae were Chrysophyta, Cyanophyta and Pyrrophyta, with a total of 29 species were identified. Average diversity index (H') and dominance index (D') values were 2.24 and 0.16, correspondingly, which means that the distribution of microalgae evenly spread and no particular species was dominant. Total microalgae abundance had an average value of 7.6 × 10⁵ cells L^-1. Water temperature and Dissolved Oxygen (DO) influenced microalgae abundance. The lowest abundance observed was 5.9 × 10⁵ cells L^-1 near a power plant station, the highest abundance was 1.04×10⁶ cells L^-1 in a touristic area.