Spatial Dynamics of Demersal Fish Assemblages off the Korean Coast in the East Sea.

This study assessed variations in demersal fish assemblages with respect to the study site and water depth. Seasonal samplings from May 2018 to March 2019 were conducted along the northern (Ayajin, Goseong) and southern (Hupo, Uljin) sites of the East Sea off the Korean coast, using commercial gill nets. Samples were collected at depths of ~50, ~80, ~150 m across the study sites, with concurrent monitoring of water column structures.

Long-term changes in the concentrations of nutrients in the marginal seas (Yellow Sea, East China Sea, and East/Japan Sea) neighboring the Korean Peninsula.

We examined the changes in the concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) in the surface waters of the Yellow Sea (YS), the southern sea (SS) of Korea, and the East/Japan Sea (ES) from 1995 to 2021. These marginal seas neighboring the Korean Peninsula maintained nutrient concentrations approximately an order of magnitude higher than those in the Kuroshio waters, indicating extraordinarily large terrestrial source inputs. Generally, the DIN concentration in the YS increased gradually due to the accumulation of terrestrial inputs, while the nutrient concentrations in the ES declined gradually mainly due to enhanced water stratification.

Tracing the sources of nutrients fueling dinoflagellate red tides occurring along the coast of Korea using radium isotopes.

It is a well held concept that the magnitude of red-tide occurrence is dependent on the amount of nutrient supply if the conditions are same for temperature, salinity, light, interspecific competition, etc. However, nutrient sources fueling dinoflagellate red-tides are difficult to identify since red tides usually occur under very low inorganic-nutrient conditions. In this study, we used short-lived Ra isotopes (Ra and Ra) to trace the nutrient sources fueling initiation and spread of Cochlodinium polykrikoides blooms along the coast of Korea during the summers of 2014, 2016, and 2017.

Increase in anthropogenic mercury in marginal sea sediments of the Northwest Pacific Ocean.

Over the past century, the addition of anthropogenic mercury (Hg) to vast areas of North Pacific marginal seas adjacent to the northeast Asian continent has tripled. Analysis of sediment cores showed that the rate of Hg addition (Hg flux) was greatest in the East China and Yellow Seas (9.1 μg m yr) in the vicinity of China (the source continent), but was small in the Bering and western Arctic Ocean (Chukchi Sea) (0.