Program     Development of monitoring methods and instruments for marine environmental parameters       Poster Development of an osmotic sampler for time-series sampling of nutrients in surface water P-SPS1-03-S Junxian Pei* , Xiamen University Quanlong Li* , Xiamen University Presenter Email: 496136703@qq.com High temporal and spatial resolution data of nutrients in aquatic environment are of great importance for studying their distribution, migration and transformation, and environmental effects. In this study, a sampler using osmotic pump (OP) as diving force was developed and applied to obtain time series concentrations of nutrients in surface waters. The sampler mainly consists of an osmotic pump, which operates with osmotic pressure, a sampling coil for sample storage, a filter and an air-bubble injector. When the sampler was deployed underwater, the OP drew the water continuously through the filter at a constant flow rate, and the sample was stored in the sampling coil. Meanwhile, the air-bubble injector delivered air bubble into the coil at fixed time to separate the sample. The air segments could be used as the stamps of the sampling time. After the sampler was retrieved, each sample was expelled from the coil into different vials depending on the air segments. Dissolved total nitrogen, dissolved total phosphorus, dissolved reactive phosphorus and nitrate in the samples were determined, and time-series concentrations of these nutrients were obtained. The sampler was deployed for 20 days and 7 days in riverine and coastal waters, respectively. Its performance was evaluated by comparison with spot sampling. The sampler ran smoothly during the deployments, and the results showed good agreement between the two different sampling methods, indicating the reliability and prosperous application in time-series sampling of nutrients in surface water.