碳氮稳定同位素技术在青藏高原高寒草甸生态系统研究中的应用:进展与展望

Carbon and nitrogen stable isotopes technology in the researches on alpine meadow ecosystem in Qinghai-Tibet Plateau:Progress and prospect

碳氮稳定同位素技术在草地生态系统研究中的应用日渐广泛,本文针对其在青藏高原高寒草甸生态系统中的研究与应用进行了总结。首先,探讨了环境因子(海拔、水肥、草地退化、温度)对青藏高原高寒草甸碳氮同位素组成(δ^13C、δ^15N)的影响:高寒草甸植物δ^13C值与海拔呈正相关,与大气压强、草地退化和温度均呈负相关,与降水的关系尚有争议;土壤δ^13C值与海拔和草地退化呈正相关;植被的δ^15N值与水肥呈正相关,土壤的δ^15N值与草地退化呈负相关。其次,综述了近年来该技术在高寒草甸植物光合型鉴定、植物水分利用、食物链营养关系、碳氮循环等方面的研究进展。最后,对碳氮稳定同位素技术在研究高寒草甸土壤有机碳与土壤呼吸、重现植被类型更替和气候演化历史、土壤N_2O溯源、探究高寒草甸退化的原因、藏药与动物食品产地溯源等方面的应用前景进行了展望,以期进一步发挥其在青藏高原高寒草甸研究中的潜力。

Carbon and nitrogen stable isotopic technique has been widely used in research of glassland ecosystems.Here,we summarized studies using carbon and nitrogen stable isotopes in the alpine meadow ecosystem on the Qinghai-Tibet Plateau.Firstly,we reviewed the environmental factors which influenced carbon and nitrogen isotope composition(δ13C andδ15N)of plants and soils in alpine meadow,such as altitude,moisture,fertilization,grassland degradation,and temperature.The values of plantδ13C were positively correlated with altitude,and negatively correlated with atmospheric pressure,grassland degradation and temperature.The relationship between plantδ13C and precipitation was non-linear.The values of soilδ13C were positively correlated with altitude and grassland degradation.The values of plantδ15N were positively correlated with soil moisture and fertilization,and negatively correlated with grassland degradation.Secondly,we reviewed the current application and progresses of 13C and 15N in the identification of plant photosynthetic type,water use,nutrient transport along food chain and carbon and nitrogen cycle in the alpine meadow.Finally,we prospected the 13C and 15N isotopes application in researches on soil organic carbon and soil respiration in the alpine meadow,transitions of vegetation type,and climate change,soil N2O trace,exploration of vegetation degradation,identification of the origin of Tibetan medicine and animal food,etc.13C and 15N isotopes could be widely used and play important roles in researches on the alpine ecosystems.