Organic and inorganic matter increase related to eutrophication in Gamak Bay, South Korea

Abstract

Water quality, the carbon isotope ratio of suspended particulate organic matter (POM), and limiting nutrients were investigated at seven surface and bottom seawater stations in Gamak Bay, South Korea, to evaluate the effectiveness of counter-measures to organic matter increase. The increase in surface water COD in Gamak Bay appear to be the result of phytoplankton growth, which is consistently limited by nitrogen (N) or phosphorous (P), but not by silicon (Si). High chlorophyll a concentrations seem to be caused by freshwater inputs of N and P associated with wastewater in the northern and northeastern portions of the Bay, and by the inflow of NH4-N and P associated with the digestion of organic matter from the bottom layer in western areas. To regulate the increase of organic matter in Gamak Bay, controlling phytoplankton growth, particularly by regulating the input of N or P, may be more important than controlling the input of terrestrial organic matter.