【摘要】 本研究基于2023年5月-7月西北太平洋现场调查数据，分析了二甲基硫（dimethylsulfide,DMS）和二甲基巯基丙酸内盐（dimethylsulfoniopropionate,DMSP）的空间分布特征及其迁移转化速率，并通过船基培养实验探究了不同铁浓度（25 nmol/L、50 nmol/L）和氮磷比（16∶1、32∶1）对DMS释放和DMSP生产的影响。结果表明，夏季西北太平洋DMS、颗粒态DMSP（DMSP_p）和溶解态DMSP（DMSP_d）平均浓度分别为（1.04±0.99）nmol/L、（8.25±9.32）nmol/L和（2.84±2.65）nmol/L，总体呈现表层浓度高、随深度增加浓度降低的特点；表层海水中DMS生物生产速率、微生物消耗速率和DMSPd降解速率的平均值分别为（2.36±0.68）nmol/（L·d）、（1.40±0.33）nmol/（L·d）和（10.40±2.93）nmol/（L·d）；此外，表层海水中DMS的主要去除途径是微生物消耗，占其生产速率的62.5%;DMS的光降解主要发生在UV波段下，UVA、UVB和可见光波段对DMS的光降解的贡献率分别为39.7%、45.5%和14.8%。船基培养实验表明，不同Fe³⁺浓度和氮磷比的添加对DMS和DMSP的释放均具有促进作用，不同Fe³⁺浓度的促进作用无明显差异，二甲基硫化物的浓度在氮磷比为32时最高。更多还原

【Abstract】 Based on the field survey data from May to July 2023 in the Northwest Pacific, the study analyzed the spatial distribution characteristics of dimethyl sulfide（DMS） and dimethylsulfoniopropionate（DMSP）, as well as their migration and transformation rate. Additionally, ship-based incubation experiments were conducted to explore the effects of different iron concentrations（25 nmol/L, 50 nmol/L） and nitrogen-tophosphorus ratios（16∶1, 32∶1） on DMS release and DMSP production. The results showed that the average concentrations of DMS, particulate DMSP（DMSP_p） and dissolved DMSP（DMSP_d） in the Northwest Pacific in summer were（1.04 ± 0.99） nmol/L,（8.25 ± 9.32） nmol/L and（2.84 ± 2.65） nmol/L, respectively, generally showing higher values in the surface layer and a decreasing trend with depth. In the surface seawater, the average production rate of DMS, microbial consumption rate of DMS, and degradation rate of DMSPd were（2.36 ± 0.68） nmol/（L·d）,（1.40 ± 0.33） nmol/（L·d）, and（10.40 ± 2.93） nmol/（L·d）, respectively. Moreover, the primary removal pathway for DMS in the surface seawater was microbial consumption, accounting for 62.5%of the removal processes. DMS photodegradation mainly occurred in the UV spectrum, with UVA, UVB, and visible light contributing 39.7%, 45.5%, and 14.8%, respectively, to DMS photodegradation. The ship-based incubation experiments showed that the addition of different Fe³⁺ concentrations and N/P ratios promoted the release of DMS and DMSP. The promoting effects of different Fe³⁺ concentrations were comparable, while a higher N/P ratio facilitated DMS release and DMSP formation.更多还原