金沙土遗址劣化过程中微生物群落结构演替研究

Jinsha Site is the first major archaeological discovery in china at the beginning of the 21 st century, which possess great historical and cultural value. Due to both natural and anthropogenic factors, the Jinsha Site have already started to deteriorate at varying degree. The deterioration is a severe threat to the preservation of Jinsha Site. Previous reports on the deterioration mechanism have mainly focused on abiotic factors. In this study, in order to reveal the influence and mechanism of soil microbial succession contribute to earthen ruins deterioration, and to make the preservation more scientific and effective, areas with different degree of deterioration in Jinsha Site were selected to be studied using metagenomics as the main method, combined with SEM-EDX, Raman-spectroscopy, XRD, IC and FT-IR. The aims are(1) to characterize microbial community structure in earthen ruins samples under different deterioration degree collected in different seasons to reveal the microbial succession in time and space; (2) to study the effect of soil physicochemical properties on the microbial succession in earthen ruins; and (3) to analyze the functional and metabolic characteristic of soil microorganisms in earthen ruins, as well as to assess the contribution of soil microbial succession to earthen ruins deterioration. Results of this project will provide guidelines for the preservation of earthen ruins both at Jinsha and at other Chinese and international sites.

金沙遗址是我国21世纪的一项重大考古发现，具有重要的历史文化价值。因自然和人为因素影响，目前遗址的部分位置已出现不同程度的劣化，严重威胁其长久保存。有关土遗址劣化机理的研究主要集中在非生物因素上，为探明土壤微生物对土遗址劣化的影响及机制，最终科学有效地保护土遗址，本研究选择金沙土遗址劣化程度不同的区域作为研究对象，以高通量测序为主要研究手段，结合扫描电镜-能谱（SEM-EDX）、拉曼光谱（Raman）、X射线衍射（XRD）、离子色谱（IC）、傅里叶变换红外光谱（FT-IR）等技术，系统研究不同季节、不同劣化程度土遗址土壤微生物群落结构特征，揭示土遗址劣化过程中微生物的时空演替，研究土壤理化性质对土遗址土壤微生物演替的影响，分析土遗址土壤微生物潜在的功能和代谢特征，探讨土遗址劣化过程中土壤微生物演替对土遗址劣化可能产生的影响机制，为国内外遗址类博物馆土遗址保护相关研究提供先导性研究案例。

本课题以金沙土遗址为研究对象，从时间和空间两个方面研究了土遗址劣化状态和劣化程度的变化与其土壤微生物演替的关系。结果表明金沙土遗址土壤中的含盐量普遍较高，主要的是MgSO4和CaSO4，随着土遗址劣化程度的加深，土壤中的SO42-、Mg2+、Ca2+的含量大幅度增加并呈现规律变化，不同劣化状态和劣化程度金沙土遗址土壤微生物的丰度和多样性存在明显差异，揭示了土壤理化性质的变化影响了土遗址土壤微生物群落组成，不同劣化状态土壤微生物群落结构具有明显的季节变化特征，细菌的群落组成变化随劣化状态的改变和劣化程度的加深呈现出明显的演替特征，而真菌群落组成变化无明显规律，功能预测和可培养菌株功能分析结果表明微生物可能通过自身产酸/碱等生理活动溶解土壤矿物进而破坏土壤结构加速土遗址劣化，获得的菌株也为后续进一步从菌株水平解析微生物在土遗址劣化过程中所扮演的角色提供了可能。本研究有助于了解土壤微生物与土遗址劣化的关系，为南方潮湿地区同类土遗址的保护研究提供了理论依据。