海洋桡足类摄食对中国东海二甲基硫释放的作用机制和转移过程的影响研究

Copepod grazing plays an important role in the production and transformation of DMS(P) (dimethylsulfide and/or dimethylsulfoniopropionate) and biogeochemical cycle of DMS, which has been received extensive attention in recent years. However, the mechanism and pocesses of copepod grazing on the production and transformation of DMS(P) has not yet been definitively elucidated up to date. In the field study, we are to investigate the biomass and species composition of phytoplankton and copepod, ingestion rate and grazing pressure of copepod in the East China Sea and the relationships between them and DMS(P) distribution. In the laboratory and mesocosm study, the mechanism of copepod grazing on DMS(P) production is to be examined by the controlled ecological experiments; the effects of copepod grazing on the transformation of DMS(P) is to be clarified by measurement of DMS(P) concentrations in phytoplankton, DMSP inside the copepods (DMSPz) and DMSP contained in faecal pellets (DMSPf). The budget of DMS(P) during the process of copepod grazing is to be revealed. The project conduces to disclose the relationships between planktonic food web structure and the dynamics of DMS(P), and its implementation provide the important guide for investigation the effects of marine copepods on the biogeochemical cycle of DMS(P) in the East China Sea.

海洋桡足类摄食在DMS(P)（二甲基硫/β-二甲基巯基丙酸内盐）的产生、转移以及DMS的生物地球化学循环中具有重要作用，近年来受到广泛关注，但桡足类摄食对DMS产生的作用机制和转移过程的影响目前尚不明确。本项目拟现场调查研究中国东海浮游植物和桡足类生物量、种类组成以及桡足类摄食率、摄食压力与DMS、DMSP分布之间的关系。通过实验室模拟以及围隔受控生态实验研究桡足类摄食对DMS(P)释放的作用机制；通过测定海洋桡足类摄食过程中浮游植物DMS(P)、桡足类体内和粪便颗粒中的DMSP含量，阐明桡足类摄食对DMS(P)转移过程的影响，揭示DMS(P)在桡足类摄食过程中的收支。本项目的实施有利于揭示浮游食物网结构与DMS(P)动力学的关系，对研究海洋桡足类对中国东海DMS(P)的生物地球化学循环的作用具有重要的科学和理论指导意义.

海洋桡足类摄食在DMS(P)（二甲基硫/β-二甲基巯基丙酸内盐）的产生、转移以及DMS的生物地球化学循环中具有重要作用，近年来受到广泛关注。针对海洋桡足类在二甲基硫循环中的重要作用，我们现场调查研究了中国东海浮游植物和海洋桡足类丰度、种类组成以及桡足类摄食率、摄食压力与DMS、DMSP分布之间的关系。通过实验室模拟以及围隔受控生态实验研究桡足类摄食对DMS(P)释放的作用机制；通过测定海洋桡足类摄食过程中浮游植物DMS(P)、桡足类体内和粪便颗粒中的DMSP含量，阐明桡足类摄食对DMS(P)转移过程的影响，揭示DMS(P)在桡足类摄食过程中的收支。结果表明，DMS、DMSP浓度与浮游植物、浮游动物、海洋细菌的种类组成和丰度有关，甲藻丰度/硅藻丰度比值较高的海域附近均存在DMSP浓度高值区。说明浮游动物摄食促进DMSP降解生成DMS。中华哲水蚤是东海桡足类的优势种，在DMS循环中扮演着重要角色，通过摄食浮游植物将DMSP进行传递和转移，桡足类摄食加速了浮游植物细胞的机械破碎，促进DMSPd的释放。实验室模拟实验结果显示桡足类日本虎斑猛水蚤摄食浮游植物能促进DMS产生，而且摄食率与温度、盐度、饵料类型和饵料浓度有关。结果可为桡足类摄食在全球DMS和DMSP的生物地球化学循环中的作用提供科学依据。