Genetic monitoring of zooplankton from Manado Bay, northern Sulawesi, Indonesia, by cytochrome oxydase I sequence

Plankton are essential components of aquatic ecosystems, serving as the base of the marine food web and playing a crucial role in global biogeochemical cycles. Understanding plankton community dynamics is vital for predicting changes in marine ecosystems, especially amid the challenges of climate change and human activities. Traditional plankton identification using microscopy requires extensive taxonomic expertise and is time-consuming, often limited by morphological complexity. To overcome these limitations, molecular methods such as DNA barcoding have been developed, allowing for rapid and accurate species identification. In this study, phytoplankton samples were collected and preserved in 95% ethanol, then processed through centrifugation and DNA extraction using the Qiaprep Miniprep Kit. The Cytochrome oxidase subunit 1 (COI) gene was amplified using universal PCR primers, and the PCR products were visualized on an agarose gel. Successful amplification products were then sequenced at First-Base Co., Selangor, Malaysia, and analyzed using Geneious software and the GenBank database via BLAST. PCR results from samples JR1-JR6 showed a band length of 725 bp. BLAST analysis for sample JR6 revealed a 90% similarity to Paracalanus aculeatus and Calocalanus styliremis, but this level of similarity is considered too low for definitive identification. This suggests that the species from sample JR6 may be a new species not yet recorded in GenBank and different from the genera Paracalanus and Calocalanus.