Guebuem Kim

We estimated the submarine discharge of groundwater (SGD) and associated nutrients into the semienclosed Bangdu Bay on a volcanic island, Jeju, Korea, by analyzing 222Rn, Ra isotopes (224Ra and 226Ra), and nutrients in seawater, pore water, and coastal groundwater. The submarine inputs of groundwater into Bangdu Bay of 120–180 m3 m−2 yr−1 (on the basis of 222Rn, 224Ra, 226Ra, and Si mass balances) were much higher than those reported from typical continental margins. The nutrient fluxes from SGD

We measured seepage rates of coastal groundwater from a volcanic island, standing in the South Sea of Korea. The seepage rates measured along the sandy coast were in the range 50–300 m/yr, which are much higher than those reported from typical continental coast. The 18 O tracer in potential seeping waters signifies that they are mixtures of basal groundwater and pristine seawaters. On the eastern coast of Jeju, almost all groundwater discharge is attributed to recirculating seawater, while fresh

We report a simple new technique for measuring low-level radium isotopes (224Ra and 226Ra) in natural waters. The radium present in natural waters is first preconcentrated onto MnO2-coated acrylic fiber (Mn fiber) in a column mode. The radon produced from the adsorbed radium is then circulated through a closed air-loop connected to a commercial radon-in-air monitor. The monitor counts alpha decays of radon daughters (polonium isotopes) which are electrostatically collected onto a silicon semicon

There has emerged a recognition that the submarine discharge of fresh, brackish, and marine groundwaters into the coastal ocean is comparable to the inputs via river discharge. However, the factors controlling submarine groundwater discharge (SGD) are poorly understood owing to a lack of SGD measurement tools in dynamic coastal waters. We observed bi‐hourly variations of the natural SGD tracers, 222 Rn and CH 4 , at a coastal seawater station over two seasons using novel monitoring techniques. T

We investigated submarine groundwater discharge (SGD)–associated nutrient fluxes and budgets in two coastal embayments, Hwasun Bay and Bangdu Bay, off the volcanic island of Jeju, Korea. SGD in Hwasun Bay is a composite of marine and meteoric groundwater, while that in Bangdu Bay mainly includes marine groundwater. The submarine inputs of groundwater into Hwasun and Bangdu Bays were approximately 0.12 and 0.27 m 3 m −2 d −1 , respectively, on the basis of the 222 Rn mass balance models. The nitr

We measured short‐lived radium isotopes ( 223 Ra and 224 Ra), dissolved inorganic and organic nutrients, and photosynthetic pigments during the summers of 2006 and 2007 in the southern sea of Korea, where harmful dinoflagellate blooms occur every year. The Ra tracer measurements reveal that coastal groundwater, rather than other sources previous suggested (i.e., Yangtze River diluted water or Kuroshio currents), is the main source of nutrients that fuel red tides in this region. Although inorgan

The naturally occurring radionuclide tracers, 234 Th‐ 238 U and 210 Po‐ 210 Pb pairs, were measured bimonthly at the Bermuda Atlantic Time‐Series Study (BATS) site in the Sargasso Sea from October 1996 to August 1997. Biological production and biogeochemical fluxes of thorium, polonium, and particulate organic carbon were highest in December 1996 and August 1997. Although the enhanced production and fluxes in December 1996 could be due to winter nitrate inputs from the subsurface ocean, those in

Abstract. The sources of dissolved organic matter (DOM) in coastal waters are diverse, and they play different roles in the biogeochemistry and ecosystems of the ocean. In this study, we measured dissolved organic carbon (DOC) and nitrogen (DON), the stable carbon isotopic composition of dissolved organic carbon (δ13C-DOC), and fluorescent dissolved organic matter (FDOM) in coastal bay waters surrounded by large cities (Masan Bay, Republic of Korea) to determine the different DOM sources in this