青海湖底层叶绿素最大值（DCM）层的形成机制研究

世界范围内在寡营养、稳定分层的湖泊中常常发现深层叶绿素最大值（DCM）层的存在，对湖泊DCM层形成过程与机制的研究是国内外研究的热点。研究显示，湖泊DCM层的形成与维持机制具有很强的地域性，不同地区湖泊DCM层的形成没有统一的控制机制。目前，对青藏高原盐碱性湖泊生态学的现场研究薄弱，尚未见对青藏高原盐碱性湖泊DCM层形成机制的研究。青海湖是青藏高原面积最大的盐碱性湖泊。我们前期研究显示，青海湖湖底存在周年DCM层。虽然前期对青海湖DCM层形成的影响因素进行了分析，但其形成与维持机制仍不明晰。本项目拟在前期研究的基础上，进一步从水体物理结构（温跃层、密度跃层、真光层深度）、营养盐条件（营养盐跃层、通量与浓度）、紫外辐射强度影响、DCM层浮游植物的适应性等方面阐明青海湖DCM层的形成与维持机制。本课题有助于深化对青藏高原盐碱性湖泊生态学过程认识和丰富世界上不同区域湖泊DCM层形成机制资料。

The deep chlorophyll maximum (DCM) layer is commonly found in oligotrophic and stratified lakes around the world. The research on the formation process and mechanism of the lake DCM layer is a hot topic worldwide. Studies have shown that the formation and maintenance mechanism of the lake DCM layer is regional, and there is no unified control mechanism for the formation of the lake DCM layer in different regions. At present, the systematic field research on saline-alkaline lake ecology of the Qinghai-Tibet Plateau is weak, and no research on the formation mechanism of the DCM layer of saline-alkaline lakes on Qinghai-Tibet Plateau was found. Qinghai Lake is the largest saline-alkaline lake in the Qinghai-Tibet Plateau. Our previous research showed that there was a year-round DCM layer at the bottom of Qinghai Lake. Although preliminary analysis on the influencing factors of the formation of the DCM layer in Qinghai Lake were conducted in the early stage, the mechanism of its formation and maintenance is still unclear. This project intends to clarify the formation and maintenance mechanism of the DCM layer in Qinghai Lake through further study of physical structure, nutrient conditions, ultraviolet radiation intensity, and adaptability of phytoplankton in DCM layer based on previous research. Results will help to deepen the understanding of the ecological process of saline-alkaline lakes on the Qinghai-Tibet Plateau and enrich the information on the formation mechanism of the DCM layer of lakes in different regions of the world.