Observations on nutrient elements and sulphate in atmospheric wet depositions over the northwest Pacific coastal oceans - Yellow Sea

Concentrations of nutrient elements (e.g. NO3−, NO2−, NH4−, PO4−3 and SiO2 etc.) and sulphate in atmospheric wet depositions (rain and snow) over the Yellow Sea (Huanghai) were examined based on the observations at two land-base stations. The results show a variability over one to two orders of magnitude of element concentrations, depending upon the source and pathway of air-mass and element. Seasonal variations can be summarized as higher concentrations of nutrient elements corresponding to low rainfall in winter and lower element levels with abundant precipitation in summer. Levels of nutrient elements in rain and snow over the Yellow Sea are quite high compared to values from remote regions, but somewhat similar to coastal oceans surrounded by Europe and North America. Examinations of element concentrations reveals that contributions of recycling sea-salts is very limited (10–20%). Elevated element concentrations are mainly from land sources emissions, which may be delivered by both natural and anthropogenic processes. Comparison with riverine input indicates that atmospheric deposition has significant impact upon marine bioproductions in this region, which may be equal to or even more important than river does. Data of this study show potential links between episodic atmospheric depositions of nutrient elements and toxic biological bloom events in the Northwest Pacific coastal oceans.