荒漠地区土壤表层固碳作用研究进展

 干旱、半干旱地区的生态环境条件脆弱，光能自养生物在荒漠地区地表的物质循环和能量流动中起着重要作用。藻类和苔藓是荒漠地区地表普遍存在的固碳生物，不仅能够改善土壤的物理性质，起到保护土壤的作用，同时能够通过特定蓝藻的固氮作用增加土壤的氮含量，最重要的是这些固碳生物能够通过光合作用固定空气中的CO₂，是荒漠地区土壤表层固碳的主要贡献者。荒漠地区生态系统固碳量的研究也是研究全球气候变化的重要组成部分，固碳量的大小不仅受自然条件的约束，也与土壤表层固碳生物（主要是藻类和苔藓）的组成密切相关。当土壤中仅有丝状蓝藻存在时固碳速率较低，随着绿藻等高等藻类和苔藓的出现，固碳速率快速增加。本文综述了荒漠地区土壤表层固碳生物组成和影响地表固碳的因素，回顾和展望了地表固碳的研究方法。

Research Progress on Carbon Fixation in Desert Topsoils

Phototrophic organisms play an important role in biogeochemical cycles of elements in desert soil ecosystems, where the ecological environment is fragile. Algae and moss are ubiquitous and can take photosynthesis in desert ecosystems. They can improve the physical properties of soil to protect the soil, and some of them have the ability of nitrogen fixation to increase soil nitrogen storage. More importantly, these phototrophic organisms are the main contributors of soil carbon storage, because they can fix carbon dioxide. The study of carbon dioxide fixation ability of desert ecosystem is an important part of the study of global climate change. The amount of fixed carbon is not only affected by the natural conditions but also closely related to the composition and abundance of phototrophic microorganisms (mainly algae and moss). The photosynthesis rate is usually low when there are only filamentous cyanobacteria in the topsoils, and the photosynthesis rate will increase when green algae and moss inhabit the topsoils. This article is to summarize the composition of phototrophic organisms in desert topsoils and the influencing factors and review and forecast the analysis methods of carbon fixation.