Scientists prove marine litter inflow from N. Korea and China

A Korean research team recently discovered that marine litters from North Korea and China were flowing into the Korean inshore through the South Sea. Despite frequent issues arising from inflowing marine litters, the recent discovery comes as the first scientific step-by-step evidence to be found.

In a joint research led by Park Yong-gyu, head of Oceanophysics Team at the Korea Institute of Ocean Science & Technology and senior researchers of the Ocean Satellite Center led by Cho Seong-ik, marine litters occurred from North Hamgyong Province in North Korea and Yanbian in China were found to have flowed into the eastern coast of Korea from August to September this year.

To detect the moving route of marine litters first found in the shores of Gangneung waters in Gangwon Province in September, the researchers analyzed the routes with its exclusively developed computer simulation program "marine floating matter movement and expansion model." As a result, researchers have concluded that the litters found in Gangneung waters were leaked near the Tumen River around Aug. 28 and moved south along the ocean currents. In a nutshell, trash from China and North Korea flowed into the East Sea through the Tumen River.

To provide scientific evidence, researchers analyzed the concentration of marine floaters near the East Sea with the Korean oceanographic observation satellite "Chollian" during the period. Chollian is a geostationary orbit, which can monitor the oceans surrounding the Korean Peninsula 24 hours. The higher the density of floaters on the sea, the higher the possibility of different amount of sunlight it will absorb. According to the findings derived from Chollian, the floaters tended to move south from the northern part of Korean Peninsula via the East Sea, as already proven by computer simulation outcomes. On Sept. 6, the density of floaters found at the Gangneung coast showed similar level at 0.7g/m³ compared to the average year. Two weeks after, the density nearly doubled than the average level at 1.3g/m³ on Sept. 20.

"By analyzing the images shot by Chollian with the floating litter movement and expansion model, we will be able not only to discover green tides and brown waters, but also to gain visibility of marine litter routes," said Hong Gi-hoon, director of the Korea Institute of Ocean Science & Technology. "The analysis will help provide scientific evidence, which can back up international issues occurring in the oceans and coasts."

송경은기자 kyungeun@donga.com