ABSTRACT
Zoobenthos is part of an animal benthic group that lives at the bottom of the sea, and which can be used as an indicator of aquatic environmental pollution. The ecosystems that are mostly inhabited by benthic organisms are the mangrove ecosystems that are scattered in coastal areas. One of the mangrove ecosystems in Indonesia is on Bira Island, which is located in the Seribu Islands. The research objectives in this study were to determine the population dynamics, abundance, diversity, and dominance of zoobenthos and to discover how the water quality affected the population dynamics of zoobenthos at the mangrove ecosystem on Bira Island during the 6 months of observation. The research method used is descriptive with survey design. The observation station was determined purposively, based on the condition of the mangrove vegetation, and the zoobenthos sampling was undertaken using the transect method. The data were analyzed descriptively by calculating the abundance, diversity and dominance. The results showed that as many as 23 species of zoobenthos were identified, belonging to 4 phylums, with the highest to lowest composition represented by mollusks, arthropods, chordates and Cnidaria, respectively. The zoobenthos population fluctuates during the observation period and tended to show a decline in population every month during the observation period. The most abundant species was represented by Uca sp and the lowest was represented by Chrysaora sp. Meanwhile, based on the observation station, the highest abundance was at station 1, followed by station 2 and 3. The diversity of zoobenthos shows a low criterion and no species dominance exists, while the environmental parameters in general are still in the normal range for zoobenthos life.
