시화방조제의 건설은 저서동물군집의 시 공간 분포에 어떠한 영향을 미쳤는가 ? = How are the Spatio-Temporal Distribution Patterns of Benthic Macrofaunal Communities Affected by the Construction of Shinhwa Dike in the West Coast of Korea ?

다국어 초록 (Multilingual Abstract)

Changes in the benthic communities have been studied to investigate the environmental effects before and after the construction of Shihwa Dike in the West coast of Korea. It is suggested that sequential changes in macrofaunal assemblages progressed in two successional directions in the Shihwa lake under the influence of organic enrichment. First, the appearance of azoic zone or grossly polluted zone developed in the area of less than 6 m in depth resulted from the severe dissolved oxygen depletion due to the eutrophication from the increased organic loading. Second, the polluted zone characterized by the proliferation of the opportunistic species in organically enriched area, was found in the vicinity of the industrial discharges and nearby fluvial inputs. This benthic community succession in the Shihwa Lake seemed to be caused by the various ecological events such as an eutrophication in this organically enriched environment after construction of the dike and other physico-chemical parameters like salinity and dissolved oxygen in the bottom water, which may be influenced by the irregular surface water discharge and dilution by outer seawater inflow through the water gate of the dike. On the other hand, the benthic communities in the outside of the dike showed that the species richness was more than doubled and the abundance increased almost seven times more than that before the dike construction. This may be a typical characteristics of the initial phase in benthic eutrophication, suggesting that an increased organic input area may have been responsible for this faunal change in the study area.