Nutrients in Atmospheric Deposition of the Yellow and East China Seas
|School||Ocean University of China|
|Keywords||nutrients atmospheric deposition primary production Jiaozhou Bay Yellow Sea East China Sea|
Wet deposition samples were collected at Fulongshan in Qingdao from January 2009 to December 2010, dry deposition samples were collected at Fulongshan from January 2009 to May 2010. Wet deposition samples were collected at Qianliyan in Northwestern of the Yellow Sea from March 2009 to December 2010, dry deposition samples were collected at Qianliyan from May 2009 to June 2010. Wet deposition samples were collected at Shengsi Archipelago in the East China Sea from January 2008 to December 2009. Using the HYSPLIT model, backward trajectories of aerosols were calculated to track their sources. Water-soluble nutrients (DINH4, DI(NO3+NO2), DIP, DSi, DON, DOP), total inorganic nutrients (TINH4, TI(NO3+NO2), TIP) and total particle phosphorus (TP) were measured in aerosol samples. Water-soluble inorganic nutrients (NH4+, NO3-+NO2-, PO43-, SiO32-) were measured in rainwater samples at three sites.At Fulongshan in Qingdao, observations show that all nutrients show higher concentrations in land-source aerosols than sea-source. In acidic conditions, the solubility of the NO3- and NO2- are not affected. While a little amount of NH4+ dissolved, a large amount of PO43- are dissolved, indicating that almost all of the NH4+ NO3- and NO2- are dissolved in the Milli-Q water, while only a little amount of PO43-dissolved in the Milli-Q water. Human activities and dust storms have significant impact on the chemical speciation and concentrations of nutriens in aerosols. Leaching of nutrients from aerosol samples show that acid-soluble inorganic phosphorus and silicon are mainly observed in dust aerosols from the Northwest territories. There are more contents of water-soluble inorganic phosphate and silicon on anthropogenic-souce aerosols and sea-source aerosols.In Jiaozhou Bay, the atmospheric deposition fluxes of DINH4, DI(NO3+NO2), DIP, DSi were 79.0,86.7,0.67 and 3.25 mmol·m-2·yr-1 respectively. Dissolved organic nitrogen (DON) represented 28% of total dissolved nitrogen (TDN) in dry deposition, and Dissolved organic phosphorus (DOP) accounted for 21% of total dissolved phosphorus (TDP) in dry deposition. Wet deposition made a larger contribution to total fluxes than dry deposition for DSi and dry deposition was found to be the main factor controlling DINH4, DI(NO3+NO2) and DIP deposition. New production simulated by atmospheric DIP deposition may account for 1.3%,0.2%,0.8% and 3.0% of marine primary production in spring, summer, autumn and winter, respectively.At Qianliyan, the atmospheric deposition fluxes were 64.1mmol·m-2·yr-1 for DINH4,65.5 mmol·m-2·yr-1 for DI(NO3+NO2),1.03 mmol·m-2·yr-1 for DIP and 2.47 mmol·m-2·yr-1 for DSi respectively, dissolved organic nitrogen (DON) represented 40% of total dissolved nitrogen (TDN) in dry deposition, and Dissolved organic phosphorus (DOP) accounted for 67% of total dissolved phosphorus (TDP) in dry deposition. Dry deposition made a larger contribution to total fluxes than wet deposition for DI(NO3+NO2) and wet deposition was found to be the main factor controlling DINH4, DIP and DSi deposition. New production simulated by atmospheric DIN deposition may account for 4.4%,6.1%,2.7% and 6.3% of marine primary production in spring, summer, autumn and winter, respectively.At Huanglongdao of Shengsi Archipelago, annual atmospheric wet deposition fluxes of NH4+, NO3-+NO2-, DIN, PO43-, SiO32- were 30.1,21.9,52.1,0.08, 2.05mmol·m-2·yr-1, respectively. According to C/P, the DIP wet deposition can bring 0.07% of new production. Although the contribution of the atmospheric nutrients deposition to the East China Sea is negligible compared with the other pathways, the sudden and large amount of rainwater nutrients supply may have important impact on phytoplankton growth and its composition. Moreover, some trace species in atmospheric deposition such as Fe and Mn are beneficial to marine phytoplankton growth.The volumn weighted mean of pH at Huanglongdao of Shengsi Archipelago was 4.46, which was the smallest of the three sites. Fulongshan Followed and Qianliyan was the largest. In dry deposition, the concentrations of DINH4, DI(NO3+NO2), DIP and DSi were higher at Fulongshan than Qianliyan in the four seasons, the concentrations were higher in spring and winter. There was no significant difference in the concentrations of DON at Fulongshan and Qianliyan in aerosols. The concentrations of DOP in aerosols were higher at Qianliyan than Fulongshan in the four seasons. In wet deposition, the concentrations of NH4+, NO3-+NO2-, PO43- were highest at Qianliyan and Huanglongdao was the lowest, while the concentration of SiO32- was highest at Fulongshan, Huanglongdao was the lowest.In Jiaozhou Bay, dry deposition made a larger contribution to total fluxes than wet deposition; while in the Yellow Sea, wet deposition made a larger contribution to total fluxes than dry deposition; there was no significant difference in atmospheric wet deposition fluxes between East China Sea and Jiaozhou Bay.