Response of Macrozoobenthos Community to the Benthic Environmental Changes in Saemangeum Intertidal Area, South Korea

Since the Saemangeum dike was constructed, artificial disturbances continue to occur in the outer area of Saemangeum due to the influence of irregular discharged water. Therefore, in this study, changes in benthic environment and macrozoobenthos community were investigated to understand the effect of environmental changes near the Saemangeum dike in the intertidal area around Sinsi-do. The mean mud content (MC) and loss on ignition (LOI) of the intertidal flat of Sinsi-do were 34.5±2.3% and 2.2±0.1%. A total of 161 species of macrozoobenthos appeared and polychaetes, crustaceans, and mollusks were dominated for 93.9% of the total number of species. Heteromastus filiformis that appeared at 94.0% of all the stations, appeared at the highest density in regions with relatively high MC. Arcuatula senhousia appeared in the region with the highest LOI, and Sinocorophium sinensis took the extreme dominance in the lowest MC. The highly polluted indicator species Capitella capitata, appeared temporarily in May 2019 with a maximum density of 48,564 indiv./m2, which is expected to have occurred temporarily through the discharged water from the inside Saemangeum dike where is relatively highly polluted. The intertidal tidal area near the Saemangeum dike has been influenced in suspended matters and sediments due to the discharged water after the construction of the embankment. Therefore, in the case of the intertidal area at the southern region of Sinsi-do where is adjacent to the Saemangeum embankment, it is considered that the irregular environmental changes caused by artificial disturbances directly affect the macrozoobenthos community.