Assessment of the Seagrass Ecosystem and Heavy Metal Concentrations at Potipot Island, Candelaria, Zambales, Philippines

The seagrass ecosystem is crucial for marine environments, providing food, habitat, and enhancing water quality while protecting coastal areas. This study examined the current status of the seagrass ecosystem at Potipot Island, Candelaria, Zambales from April 2022 to April 2023, on heavy metal concentrations. Four species of seagrasses were present in the study area: Cymodocea rotundata, Halodule uninervis, Syringodium isoetifolium, and Thalassia hemprichii. Seven species of seaweeds were also found. Species diversity was low (H’= 1.6) based on Fernando’s Scale (Fernando, 1998), indicating relatively low species richness and an uneven distribution of individuals. The community was largely dominated by C. rotundata. Heavy metals were analyzed in sediments, water and in two dominant species of seagrass. Fe was found to be the highest (1,150 mg kg-1) in the sediment, followed by Cr (11 mg kg-1), Ni (8.5 mg kg-1), As (1.5 mg kg-1), and Cu (0.7 mg kg-1). Cd, Pb, and Hg were not detected. Heavy metals in water samples were detected at acceptable levels based on USEPA 2022. Moreover, heavy metal analysis of two dominant species of seagrass (C. rotundata and T. hemprichii) showed that iron was detected at the highest level of concentration (563 mg kg-1) and Cr, Cu, and Ni were also detected s, exceeding the acceptable limit based on USEPA 2022, indicating that both species absorbed heavy metals. These findings underscore the importance of regular monitoring and strengthened coastal management measures to mitigate potential sources of heavy metal pollution and support the conservation of seagrass ecosystems in Potipot Island.