Effect of Pseudocnus dubiosus Density on Organic Matter Bioremediation in Marine Sediments from El Ferrol Bay (Áncash, Peru)

This study evaluated the influence of Pseudocnus dubiosus density on the bioremediation of organically enriched marine sediments collected from El Ferrol Bay (Áncash, Peru). A laboratory experimental design was applied, comprising one control treatment without organisms and three treatments with increasing densities of P. dubiosus (27, 41 and 54 individuals per experimental unit), each with three replicates. The physicochemical parameters of the system, sediment organic matter reduction and the organoleptic changes associated with the process were assessed. The results showed that the presence of the organism significantly enhanced organic matter removal compared with the control, which achieved only a 0.97% cumulative reduction, whereas the treatments with organisms reached 34.42%, 40.97% and 43.36%, respectively. In the higher-density treatments, turbidity increased, while nitrate, phosphate and chemical oxygen demand (COD) decreased, suggesting intensified bioturbation, particle resuspension and transformation of organic compounds at the sediment–water interface. Although all evaluated densities produced a favourable functional response, the greatest numerical efficiency was recorded at the highest density. Overall, the findings support the potential of P. dubiosus as a benthic organism for application in bioremediation strategies aimed at coastal ecosystems degraded by organic matter accumulation.