Significant and conservative long-range transport of dissolved organic nutrients in the Changjiang diluted water

• Published in: Scientific reports 2018-08, Vol.8 (1), p.12768-7, Article 12768
• Main Authors: Kwon, Hyeong Kyu, Kim, Guebuem, Hwang, Jeomshik, Lim, Weol Ae, Park, Jong Woo, Kim, Tae-Hoon
• Format: Article
• Language: English
• Subjects: 704/172/169/827; 704/47/4112; 704/829/827; Dissolved organic nitrogen; Humanities and Social Sciences; multidisciplinary; Nutrient sources; Nutrients; Rivers; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-31105-1

The Changjiang River is one of the main nutrient sources in the northwestern Pacific marginal seas. However, most of the previous studies have neglected the long-range transport (>200 km) of riverine nutrients since they are rapidly consumed. In this study, we examined the long-range transport (200–800 km) of nutrients in the surface layer during the summer of 2017. The plots of nutrients against salinity display that dissolved organic nitrogen (DON) was conservative over ~800 km, while more than 99% of the dissolved inorganic nitrogen (DIN) was removed within 200 km. As a result, in the study region, DON concentrations (avg. 7.0 ± 1.3 µM), which are minor in the river water, were much higher than DIN concentrations (avg. 0.28 ± 0.26 µM). Both nutrients, N and P, showed a similar pattern. Our results suggest that dissolved organic nutrients play a critical role on the long-range transport of riverine nutrients in surface waters and subsequent ecosystem changes.