海口湾微塑料时空分布、微藻-微塑料团聚体形成机理及其环境效应研究

In recent years, microplastics pollution has attracted much attention in the world. However, only quite limited studies focused on the toxicological effects of microplastics on microalgae, the important primary producers in marine ecosystem. This project aims to the demands of Hainan national strategy in China’s strategy toward the South China Sea. Haikou Bay will be targeted as the investigation area since it plays an important role in Hainan Island. The spatial and temporal distribution patterns of microplastics pollution, including the content/properties of microplastics in the seawater and the sand on the beach, will be investigated. Meanwhile, consider the possibilities that more complicated microalgae-microplastics aggregates may be formed under the interactions of microalgae and microplastics, some indoor experiments will be conducted to: 1) investigate the influence of important parameters in terms of UV radiation, temperature and salinity on the microplastic aging and microalgal growth; and 2) further elucidate the toxicological effects of microplastics on microalgae; 3) verify the effects of microplastics on the formation of microalgae-microplastics aggregates and the corresponding aggregation formation theories; and 4) study the potential environmental effects caused by the aforementioned aggregates. Based on this project, it is anticipated to explore the potential influences of microalgae-microplastics aggregates, and this will be effective on the prediction of the transport and fate of microplastics, the control of microplastic pollution. It also offers theoretical and practical meanings to the guarantee of the water quality in the South China Sea.

近年来，微塑料污染在国内外逐渐受到关注，但其对海洋生态系统中重要初级生产者微藻的毒理效应研究较少。本项目瞄准中国“南海战略”—“海南国家战略部”需求，并根据海口湾在海南岛占据的重要位置，拟以热带近海海域海口湾为研究区域，研究分析海口湾近海海域及沙滩中微塑料污染时空分布规律。同时，结合微塑料与微藻相互作用后可形成复杂团聚体的可能性，通过室内模拟实验探讨重要环境因素（如UV，温度，盐度）对微塑料老化和微藻生长的影响；研究微塑料污染对微藻的毒理效应；并比较不同微塑料对微藻-微塑料团聚体形成的影响，明确团聚体形成机理；阐明团聚体的潜在环境效应。通过该项目研究以期探明海口湾微塑料污染情况，探讨微藻-微塑料团聚体的潜在影响，对预测微塑料归趋、控制微塑料污染、保障我国南海海域水环境质量有重要的理论和现实意义。

为探究海口湾近岸海域微塑料的分布特征及环境因素影响下微塑料的老化规律及环境效应，本项目从野外调查及室内模拟两方面进行了基础性研究。主要内容包括：1）系统采集了海口湾不同功能区的表层海水和沉积物，探明了微塑料的赋存状态及污染现状，明确了海口湾微塑料丰度水平及空间分布特征；2）基于5种模拟环境条件，开展了微塑料的室内老化实验，研究了不同环境因素对微塑料老化过程及特征的影响机理，辨析了微塑料对共存的典型污染物如重金属的吸附特性；3）基于微塑料-微藻共存团聚实验，揭示了不同特征微塑料与多种类型微藻团聚过程及机制，并进一步阐明了不同老化程度微塑料及其与典型污染物的复合毒性对微藻及团聚体的毒理效应及机理。本项目的研究结果可为进一步厘清海南近岸海域微塑料污染提供基础数据，以及为评估微塑料的潜在环境风险及防控提供理论依据。