Changes in the Abundance and Distribution of Benthic Mollusks in Polluted Sediments of a Shallow Subtropical Estuary

To quantify the ecological impacts of organic sediments and environmental dredging, benthic mollusks were chosen to serve as bioindicators of environmental change, measured as sediment organic content and associated parameters. Data on species richness, biodiversity, and abundances were collected alongside sediment and near-bottom water quality data before, during, and after environmental dredging. Organic sediment content was found to have an inverse logarithmic relationship with benthic mollusk biodiversity, species richness, and abundance. Sediments with lower organic content had higher biodiversity (up to 1.337), while sediments with higher organic content had low biodiversity (0-0.6667). Post-hoc analyses found that percent dissolved oxygen, which correlates with sediment organic content, was responsible for 29.31-34.12% of the benthic mollusk community variation.