Perpetual atmospheric dry deposition exacerbates the unbalance of dissolved inorganic nitrogen and phosphorus in coastal waters: A case study on a mariculture site in North China

Abstract

The monthly magnitudes of dissolvable nutrients through atmospheric dry deposition (ADD) and their ecological effects to the coastal waters around the Yangma Island, North Yellow Sea, were investigated for one year. The results indicated that anthropogenic activities were the major sources of dissolvable inorganic and organic nitrogen (DIN and DON); dust events were the major sources of inorganic phosphorus (DIP) and silicate (DSi); however, organic phosphorus (DOP) could be originated from marine biological activities. The annual ADD fluxes of DIN, DON, DIP, DOP and DSi were 21.8, 2.7, 0.10, 0.30 and 0.73 mmol m−2 yr−1, respectively. Overall, the new production supported by the bioavailable nitrogen through ADD in winter was up to 9.14 mg C m−2 d−1. Notably, the annual molar ratio of DIN/DIP through ADD was 216 ± 123, which was much higher than that of the dissolved inorganic nitrogen to phosphorus in seawater and might exacerbate their unbalance in some coastal waters.