Diatoms as Bioindicators of Ecological Stability in the Mangrove Ecosystem of Benoa Bay, Bali

Mangrove ecosystems play a crucial role in maintaining the ecological balance of coastal environments through various functions, including providing habitats, storing carbon, and protecting shorelines. However, increasing anthropogenic pressures have caused degradation in several mangrove areas, including Benoa Bay, Bali. This study aims to analyze the diatom community structure in the Benoa Bay mangrove ecosystem. Sediment samples were collected from five stations using a purposive sampling method and a Russian corer. The samples were processed and identified based on morphological characteristics using a microscope at 1000* magnification. Three ecological indices were calculated using PAST 4.0 to assess the diatom communities: the Shannon-Wiener diversity index (H'), the dominance index (D), and the evenness index (E). The results showed that the Shannon-Wiener diversity index (H') ranged from 3.328 to 4.243, indicating a high level of diatom diversity across the sampling stations. The other index values showed that the dominance index (D) ranged between 0.021 and 0.076, while the evenness index (E) varied from 0.3667 to 0.6888. The combination of these indices suggests that most sampling stations support a well-balanced diatom community, characterized by low dominance and high evenness, which reflects relatively stable environmental conditions. In contrast, Station 1 showed the highest dominance and lowest evenness, indicating possible environmental stress.