东海赤潮区浮游植物类腐殖质的贡献量及其形成机制研究

Phytoplankton-derived organic matter could directly result in the formation of humic-like fluorescent dissolved organic matter (FDOM) facilitated by microbial processing of precursor fluorophores, which has impacted the cycling of FDOM in the eutrophicated coastal ocean. However, the complexity of phytoplankton diversity and humic-like FDOM sources in the coastal ocean restricted the study of humic-like FDOM production and microbial processing of phytoplankton-derived aggregates. The project will focus on the algal bloom area of Eastern China Sea in spring and summer, investigating the optical components of particulate organic matter to characterize the community difference in sources of intracellular fluorophores derived from phytoplankton. And the study will combine excitation-emission matrices spectra with ultrahigh resolution Fourier transform ion cyclotron mass spectrometry to characterize the molecular composition of particulate organic matter and dissolved organic matter derived from the laboratory cultures of bloom-forming algae, which would clarify the role of microbial processing on the formation of humic-like FDOM. Results will be employed to elucidate the community difference in humic-like FDOM production and the microbial transformation mechanism of humic-like FDOM derived from phytoplankton. This project will provide an important basis for the study of the migration and transformation of FDOM in the eutrophicated coastal ocean.

浮游植物在微生物作用下会直接转化形成类腐殖质，这些类腐殖质的形成已成为干扰近岸富营养化海域荧光溶解性有机质迁移转化的重要因素之一。然而，浮游植物的多样性和类腐殖质源的复杂性限制了近岸海域浮游植物类腐殖质形成机制及其贡献量的研究。本项目拟以东海赤潮区为研究对象，详细分析春夏季节赤潮高发区浮游植物颗粒有机质的光谱组分，从源头表征浮游植物类腐殖质种类和含量的群落差异性；并应用室内培养实验，在研究东海典型赤潮藻类腐殖质种类和含量种间差异性的同时，结合傅里叶变换离子回旋共振质谱技术从分子尺度研究浮游植物颗粒态和溶解态类腐殖质的组成，深入剖析浮游植物类腐殖质的微生物溶解转化过程。这些成果将会有助于阐明浮游植物类腐殖质可能的形成机制及其贡献量的群落差异性，为研究近岸富营养化海域荧光溶解性有机质的迁移转化提供重要的科学依据。

本项目拟以东海赤潮区为研究对象，详细分析春夏季节赤潮高发区浮游植物颗粒有机质的光谱组分，从源头表征浮游植物类腐殖质可能的贡献量；并应用室内培养实验，在研究东海典型赤藻类腐殖质种类和含量种间差异性，发现两种典型赤潮藻源头类腐殖质的含量没有明显差异。结合傅里叶变换离子回旋共振质谱技术从分子尺度研究浮游植物颗粒态和溶解态类腐殖质的组成，发现浮游植物在微生物作用下的转化主要为含氮化合物的脱氮脱水反应及含氧化合物的功能团去除作用，为研究近岸富营养化海域荧光溶解性有机质的迁移转化提供重要的科学依据。