深水抚仙湖沉积物有机质矿化对界面磷再生的驱动机制

湖泊富营养化和外源污染造成沉积物有机质持续积累，而由此产生的潜在次生污染，尤其是内源磷污染，并未引起足够重视。本项目针对深水抚仙湖沉积物有机质快速积累、底层高强度磷释放的问题，通过同位素技术和生物标志物考察不同来源有机质沿水深梯度的降解特征和矿化途径；利用31-P核磁共振、薄膜扩散梯度技术、磷酸盐氧同位素等技术手段研究有机质矿化对有机磷降解、矿物相磷转化、界面磷释放等磷再生过程的影响，结合沉积物界面微环境的分析，进一步揭示有机质矿化对沉积物磷再生的驱动机制。本项目的实施将为评价深水湖泊有机质积累区沉积物磷的污染风险提供科学依据。

The continuous deposition of organic matter in sediment caused by lake eutrophication and exogenous pollution would result in potential secondary pollution, especially internal phosphorus pollution in lake, which still hasn't aroused enough concern. The present study is focusing on a trend toward an increase in organic matter enrichment and phosphorus release in sediment of Lake Fuxian. The techniques of isotopes and biomarkers are performed to characterize the degradation processes and the mineralization pathways of organic matter derived from different sources in sediment along water depth gradient. The combination of phosphorus-31 NMR, diffusive gradients in thin films technique (DGT), oxygen isotopes of phosphate is conducted to assess the effect of organic matter mineralization on benthic phosphorus dynamic such as organic phosphorus degradation, transformation between mineral phases of phosphorus, and benthic phosphorus flux across sediment interface. Furthermore, the study enhances the understanding of the mechanism of organic matter mineralization on phosphorus regeneration by investigating microenvironmental behavior at sediment interface. The findings will provide scientific support for the risk evaluation of internal phosphorus loading from organic matter accumulated sediments in deep water.