Functional Role of Water Purification on a Tidal Flat Ecosystem : Removal of Particulate Organic Matters by Macrobenthic Filter Feeders

초록

In this study we defined the functional role of water purification of a tidal flat ecosystem as removing of particulate organic matter from the overlying water. Specially designed transparent benthic chambers were deployed to measure the in situ removal rates of POM by the macrobenthic community in Seonjae intertidal area, dominated by bivalve Ruditapes philippinarum, located in Kyeonggi Bay, western coast of Korea. With each chamber, concentrations of PON, POC, chlorophyll-a and pheopigment were measured and clearance rates or filtration rates were calculated. The clearance rate per unit biomass of macrobenthos was 0.56ℓ/hr/g meat dry wt. The removal rate of PON per unit area on Seonjae tidal flat was 105.51㎎N/㎡/day, and 2,205㎏N/day from the whole area of Seonjae tidal flat (20.9km2) as calculated by the clearance rate and the average concentration of PON (0.086㎎N/ℓ) of the overlying water. Though these removal rates might be underestimated due to the cold water temperature of 9.2℃ during the in situ experiment, the economic value of this PON removal function of the community was evaluated same as the capacity of sewage disposal station of Inchon city which treats 11 tons of particulate organic matters a day in terms of COD.