PRELIMINARY STUDY OF INDIGENOUS MICROALGAE FROM URBAN AND PEATLAND WATERS IN PEKANBARU UNDER NUTRIENT-LIMITED MEDIA

Abstract

Microalgae inhabiting urban waters and peat-influenced aquatic systems experience variable environmental pressures, potentially leading to adaptive responses to conditions with fluctuating nutrient availability. This study aimed to identify microalgae cultured from several urban water bodies and peat waters in Pekanbaru and to evaluate their growth responses in culture media with different nutrient compositions using an image-based approach. Water samples were collected from multiple locations and cultured in modified BG-11 and BBM media. The growing microalgae were identified based on their morphological characteristics, while culture growth was qualitatively assessed using the mean pixel intensity (MPI) values of digital images. The study recorded 16 species from 10 microalgal genera belonging to the classes Cyanophyceae, Chlorophyceae, and Zygnematophyceae, exhibiting unicellular, colonial, and filamentous morphologies. Culture observations revealed changes in MPI values over the observation intervals, indicating increased microalgal growth rates in the growth media. These findings suggest that local microalgae from urban and peat waters possess a high tolerance to limited nutrient conditions and provide baseline information on the diversity and growth responses of indigenous microalgae in tropical urban and peat aquatic systems.