In order to evaluate the effect of heavy rainfall on nutrients in the coastal environment, we measured the concentrations of organic and inorganic nutrients in seawater at the Geum River Estuary in August 2021 (weak rainfall) and August 2022 (heavy rainfall). The correlations between dissolved organic carbon (DOC), particulate organic carbon (POC), dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP), dissolved silicate (DSi) and salinity showed the significant negative correlations (r²>0.8) in August 2022. The concentrations of DOC, POC, DIN, and DSi were higher up to 10 times in August 2022 than in August 2021. In order to determine the origin of DOC, we measured fluorescent dissolved organic matter (FDOM) and identified components (C, M, and T peak) using PARAFAC modeling. The correlations between peak M, peak C, peak T and DOC showed the significant positive correlations (r²>0.9) in August 2022. This study cannot exactly discriminate origin of DOC due to inputting various sources through heavy rainfall. Therefore, in order to determine the origin of organic matter, studies on ¹³C, ¹⁸O, and molecular structure are necessary.

Primary Presenter: MINYOUNG LEE, Chonnam university (dlalsdud2005@naver.com)

Authors:

U-Seong Kim,   ()

Yongwon Kim,   ()

Tae-Hoon Kim, Chonnam National University  (thkim80@jnu.ac.kr)

Minyoung Lee,   ()