大气沉降提供的氮、铁、锌等物质可直接或间接影响海水中溶解态有机磷（DOP）的转化利用。然而，相对于开阔大洋，近海DOP利用机制及其与大气沉降之间的联系尚不明确。申请人之前在黄海开展的培养实验表明，沙尘加富可能通过促进DOP的转化利用提高海水中生物可利用性磷的总量，但仍需直接证据予以证明。针对我国黄海磷限制日益普遍的现状，本项目拟从黄海近岸至中部选取三个代表不同营养水平的站点，开展营养盐（氮、磷）、金属（铁、锌）等单因子及大气颗粒物、雨水加富的船基围隔培养实验。研究主要包括两方面：1）分析培养期间营养盐、碱性磷酸酶活性、浮游植物生长及粒级结构变化，揭示不同营养水平条件下氮磷比和铁、锌对DOP转化利用的影响；2）将大气颗粒物、雨水与金属、营养盐加富实验结果对比，阐明大气沉降物质中影响浮游植物利用DOP的主控因子。本研究从大气沉降调控DOP利用角度提供了缓解近海磷限制的新思路。

The nitrogen (N), iron (Fe), and zinc (Zn) input by atmospheric deposition can affect the utilization of dissolved organic phosphorus (DOP) for phytoplankton in direct or indirect ways. Compared with the related studies in the open ocean, the detailed regulating mechanism of the utilization of DOP and its relationship with atmospheric deposition in coastal seas is still unclear. The microcosm incubation experiments we conducted in the Yellow Sea demonstrated that dust additions likely increased the bioavailable P stock in the incubated seawater by the utilization of DOP, but we still need direct proofs to verify our ideas. In view of the increasing prevailed phenomenon of phosphorus (P) limitation in the Yellow Sea, this project is going to carry out onboard microcosm incubation experiments amended with nutrients (N, P) and metals (Fe, Zn), as well as aerosol particles and rainwater at three stations characterized by varying trophic states selected from the coastal to the central part of the Yellow Sea. The main research content includes: 1) the effect of N:P ratios and Fe, Zn on the utilization of DOP at varying trophic states will be evaluated by analyzing nutrients, alkaline phosphatase activities, phytoplankton growth and size structure; 2) By comparing the results of aerosol particles and rain water additions with that of nutrient and metal additions, we aim to find the main factor in the aerosol particle and rainwater that regulates the utilization of DOP at varying trophic states. This study develops a new idea that the regulation effect of atmospheric deposition on the utilization of DOP has a potential to alleviate the limitation of P in coastal seas.