Atmospheric Nutrient Deposition At The East China Coast And Its Impact On Marine Primary Production

In this research, dry and wet deposition samples were collected at three coastal sites,Qingdao, Qianliyan and Zhoushan. Using the NOAA HYSPLIT₄ model, backward trajectories of aerosols are calculated to track their sources. Water^-soluble nutrients (DI(NO₃+NO₂), DINH₄, DON, DIP, DOP, DSi), acid-soluble nitrogen and phosphorus (TI(NO₃+NO₂), TINH₄, TIP) and total particle phosphorus (TP) are measured in aerosols samples at Qingdao, and only water-soluble inorganic nutrients at Qianliyan and Zhoushan. Dissolved species of nutrients (DIN, DON, DIP, DOP and DSi) in rainwater were analyzed at all three sites. Nutrients fluxes of atmospheric input to coastal zone are estimated and impacts on marine primary production were studied. Besides, on-board microcosm experiments were performed to study the response of marine phytoplankton to rainwater nutrient addition in East China Sea (ECS) surface water.At Fulongshan of Qingdao, The results indicate thatâ‘ all nutrients show higher concentrations in land-source aerosols than sea-source;â‘¡land-source aerosols have more phosphorus, but smaller DIP/TP ratio than sea-sourceâ‘¢in winter, solubility of aerosol inorganic phosphorus is obviously highâ‘£in aerosols collected during three dust storm, NO₃^-+NO₂^- and NH₄⁺ are much lower than other samples, and the DIP and DSi transport to the East China Sea and Yellow Sea (YS) by dust storm are 1.5×10⁹ mol yr^-1 and 4.7×10⁸ mol yr^-1, which is 11% and 2.1% of river inputs, respectively.In Jiaozhou Bay (JZB), dry and wet deposition of atmospheric nutrients show seasonal variations and can contribute 55%,12%,15% and 2% to inputs of nitrate, ammonia, phosphate and silicate from land, respectively. New production simulated by atmospheric DIP deposition may account for 6% to 46% of marine primary production in the JZB, where P or Si is likely to be the limiting element for phytoplankton growth.