Phosphorus(P),as a limiting nutrient,plays a crucial role in the mountainous ecosystem development.Its biogeochemical cycle in mountainous ecosystems determines the bioavailability and sustainable supply of P,and thus becomes a crucial process which needs to be fully understood and described for ecological and environmental conservation.However,most of research about P biogeochemical processes has been carried out in aquatic environment and agronomic field,but rare researches have been done in mountain ecosystem.In the present review,we summarize researches on P biogeochemical cycle concerning mountain ecosystem in recent decades,including rock weathering,the release,transformation and bioavailability of P,interactions between the P biological cycle and microbial and plant life,as well as the development of models.Based on the state of art,we propose the future work on this direction,including the integration of all these research,the development of a practical model to understand the P biogeochemical cycle and its bioavailability,and to provide a reference for ecological and environmental conservation of mountainous ecosystems and lowland aquatic systems.
New terrestrial habitats have emerged and a primary succession has developed in the retreat area （29°34＇N, 102°oo＇E, 2951-2886 m） after the retreat of the Hailuogou glacier. To investigate soil microbial changes along the primary successional chronosequence, mixed soil samples were collected at six sites at different ages （2 young sites, 2 mid-aged sites, and 2 old sites）. The RNA was extracted and amplified. Bacterial 16S rRNA and fungal 18S rRNA were analyzed using high-throughput 454 pyrosequencing analysis. Overall, pyrosequeneing showed that Proteobacteria, Acidobacteria, Baeteroidetes and Actinobacteria were the main bacterial phyla, and the fungal communities were strongly dominated by the phyla Ascomyeota and Basidiomyeota in the retreat area. The Shannon diversity index （Hshannon） of bacteria was 6.5 - 7.9, and that of fungi was 2.2 - 4.1 in these sites. For the bacterial communities, diversity and evenness values were highest on the mid-age sites and were relatively low on the young trend was observed for the and old sites. A similar fungal communities. In contrast, soil properties showed significant linear distributional trends （increase or decrease） with the age of the site. Combining the linear change patterns of soil properties, the highest values of bacterial and fungal evenness and diversity in the mid-aged sites indicated that there was less environmental stress and more niches for microbial communities in the middle successional stage compare with other stages. In addition, our analysis showed that microbial communities were the main drivers that build a soil organic matter pool to expedite pedogenesis for ecosystem succession. This primary succession in the Hailuogou glacier retreat area is developing rapidly compared with that in other glacier retreats.
Dear Editor,Phosphorus（P）ultimately comes from rock weathering in natural ecosystems（Porder et al.,2007）,and thus solubilization of rock phosphate plays a crucial ecological role in P supply for the ecosystems.Especially,microbial solubilization of rock phosphate is a vital process for the replenishment of available P in alpine ecosystems where the weathering degree of soil is low.
磷(P)的生物有效性对山地生态系统的发育和稳定至关重要。由于大气CO_2浓度升高和N沉降增加,生态系统C、N和P的化学计量比失衡,P的生物有效性受到更多关注。近年来山地系统中P的研究不断深入,2004—2013年间ISI Web of Knowledge中相关研究论文几乎是此前近百年的3倍。总结了山地生态系统中P的生物有效性的特点及其对植物物种多样性和初级生产力的影响。山地生态系统P的生物有效性因垂直高差和地形梯度空间变异明显,快速物质运移和生物过程是控制山地生态系统P的生物有效性的关键因素。P的生物有效性可以影响山地生态系统物种多样性和初级生产力,其对初级生产力的限制存在于全球范围内的山地生态系统。当P的生物有效性发生改变时,山地生态系统的结构越复杂,其植物物种多样性和初级生产力的响应可能会越平缓。全球变化的重要驱动因子(如增温和N沉降增加)可以直接或间接地改变山地生态系统P的生物有效性,因此需要在山地生态系统中加强长期监测和养分控制实验,并结合新型P分析技术,以期认识山地生态系统P的生物有效性的现状、变化趋势和对生态系统的影响,从而为适应全球变化背景下山地生态系统养分状况的改变提供依据。
