Filamin B의 ISG15에 의한 modification에 관한 연구

Thesis(master`s)--서울대학교 대학원 :생명과학부,2005.Maste

Reduction of atmospheric N deposition and C uptake in the coastal areas of the Yellow Sea of the Northeastern Pacific Ocean for COVID-19 period

Since the Yellow Sea is located between Northern China and the Korean Peninsula, abundant atmospheric nitrogen (N) has been deposited in the Yellow Sea, implying an increase in new primary productivity (NPP). However, during COVID-19, NPP decreased due to lower human activities such as fossil fuel combustion and vehicle exhaust. We monitored atmospheric inorganic N (nitrate; NO3– and ammonium; NH4+) deposition and analyzed isotope of δ15N and δ18O-NO3– and δ13C-TC and δ15N-TN in total suspended particles (TSP) before (2018) and during COVID-19 (2021) to investigate how decreased human activities affected the N deposition and NPP in the coastal of Yellow Sea. During COVID-19, the inorganic N deposition decreased by 71% for summer and 81% for winter compared to before COVID-19. The estimated NPP from the conversion of deposited N to C decreased by 88.6 mmol C m–2 yr–1 from 2018 to 2021. This could weaken the capacity of phytoplankton to absorb CO2 due to reduced atmospheric N inputs to the ocean. The values of δ15N and δ18O-NO3– exhibited a similar trend in 2018 and 2021, higher in winter and lower in summer, implying no change in the main sources of atmospheric N, such as fossil fuel combustion for winter and vehicle exhaust for summer. Using a Bayesian mixture model to determine the relative contribution of various sources, based on δ13C-TC and δ15N-TN values from our samples and reported end-members in the literature, we found that in 2018, when human activity was high, coal combustion was the main source, while in 2021, vehicle exhaust was the main source.2

The study on the physicochemical properties affected by the opening of the weir at th Geum Estuary in the Republic of Korea

The decline in river water quality significantly impacts estuarine environments, highlighting the interconnectedness of these ecosystems. In South Korea, the opening of river weirs aimed to restore river ecosystems and improve water quality, which reportedly led to habitat restoration. However, research on the implications for linked estuaries remains limited. Our study focused on the Geum Estuary, examining physicochemical properties during the initial weir opening in 2018 and the stabilization phase in 2021. We found that nitrate(NO3-) inputs from rivers to the estuary decreased by 19 ~ 68 % from 2018 to 2021. Despite this, the concentration of NO3- in the estuarine water column exhibited fluctuations during this period, and there was no notable change in polluent sources. In contrast, phosphate(PO4-) and silica(SiO2) levels were higher in 2021, suggesting that previously accumulated PO4- and SiO2 in the weirs may have been released into the estuary following their opening. This influx of PO4- could stimulate phytoplankton growth, which is often limited by phosphorus due to excessive NO3- inputs from rivers. To mitigate potential negative impacts, we recommand dredging accumulated sediments in weirs before their opening to prevent the release of PO4- and SiO2 into estuaries. This approach could help maintain the balance of nutrients and support the health of estuarine ecosystems.2