Assessing the atmospheric deposition of inorganic nitrogen and phosphorus over the Yellow Sea

Abstract

As an important fishery area in the world, the environmental status of fishery resources in the Yellow Sea is closely related to atmospheric deposition. Considering the differences in the distribution of atmospheric pollutants in different regions, in order to improve the accuracy of the assessment, the Yellow Sea was divided into three representative regions, and a method for assessing the deposition fluxes of inorganic nitrogen (DIN) and phosphorus (DIP) in large-scale marine atmospheres was constructed. Based on the particle size distribution of atmospheric particulate DIN and DIP in 10 subsections, the dry deposition rates of different DIN and DIP were obtained by refinement. On this basis, atmospheric deposition of DIN and DIP to the Yellow Sea were estimated by combining the collected measured data and empirical coefficient estimations. The results showed that in 2017 the dry deposition of atmospheric DIN in the Yellow Sea was equal to 1.71 × 10⁵ t. NO₃^--N was the most important component in the dry deposition of DIN (74.3 %), followed by NH₄⁺-N (24.4 %). Unlike dry deposition, the wet deposition amount of NH₄⁺-N (2.55 × 10⁵ t) was higher than that of NO₃^--N (2.02 × 10⁵ t). The amounts of total deposition of NO₃^--N, NH₄⁺-N, NO₂^--N, and DIP were 3.29 × 10⁵ t, 2.89 × 10⁵ t, 4.94 × 10³ t, and 2.93 × 10³ t, respectively. In the Western Yellow Sea, the amounts of DIN inputs from the atmosphere and from rivers were comparable. The fluxes of NO₃^--N and DIP from rivers are significantly higher than those from atmosphere, while the opposite is true for NH₄⁺-N. So the contribution of atmospheric deposition to the input of nutrients in the Yellow Sea cannot be ignored. The total atmospheric deposition fluxes of DIN and DIP were highest in summer, which may be related to the high incidence of harmful algal blooms during the summer period.