維管植物和生物土壤結(jié)皮的鑲嵌式分布是中亞荒漠區(qū)地表覆蓋的主要形式,。在這一地區(qū)，生物土壤結(jié)皮占據(jù)了地表40%以上的面積,，由于生物土壤結(jié)皮的潛在光合能力與維管植物相當,，據(jù)此推測，結(jié)皮發(fā)育土壤在干旱區(qū)碳循環(huán)中可能具有重要的作用,，然而,，相關(guān)的研究多集中于室內(nèi)條件下生物土壤結(jié)皮的光合生理測定方面。
中科院新疆生態(tài)與地理研究所張元明研究員領(lǐng)導的“生物土壤結(jié)皮生態(tài)學”研究團隊在“973”項目和國家自然科學基金的資助下,，圍繞干旱荒漠區(qū)生物土壤結(jié)皮發(fā)育土壤的碳通量特征這一科學問題,，實測研究了古爾班通古特沙漠生物土壤結(jié)皮在荒漠土壤-大氣界面碳交換中的作用,。
研究表明，生物土壤結(jié)皮在土表的發(fā)育顯著阻礙了土壤CO2向大氣的釋放,，地表生物土壤結(jié)皮能有效減少1/4至1/2的土壤碳釋放,，顯著影響土壤-大氣界面碳交換過程。這一結(jié)果說明,，生物土壤結(jié)皮在荒漠土壤-大氣界面碳交換中扮演重要角色,。在這一生態(tài)過程中，自然條件下土壤水分和溫度的耦合關(guān)系起著關(guān)鍵性作用,。溫度變動（10至300C）對生物土壤結(jié)皮的光合作用無顯著影響,，但溫度的升高卻能顯著刺激土壤呼吸；相反,，低溫能延長結(jié)皮光合活性時間,，增加了結(jié)皮發(fā)育土壤的碳截獲量。這一結(jié)果暗示,，早春融雪和積雪覆蓋期可能是生物結(jié)皮發(fā)育土壤碳截獲的主要時段,。（生物谷Bioon.com）
生物谷推薦的英文摘要
Soil Biology and Biochemistry doi.org/10.1016/j.soilbio.2012.12.006
Carbon flux in deserts depends on soil cover type： A case study in the Gurbantunggute desert， North China
Y.G. Su,， L. Wu,， Z.B. Zhou， Y.B. Liu,， Y.M. Zhang
Carbon flux represents carbon uptake from or release to the atmosphere in desert ecosystems,， yet the changing pattern of carbon flux in desert ecosystems and its dependence on soil cover type and rainfall amount are poorly understood. We measured net carbon fluxes (NCF) in soil with four cover types (moss crusted soil， cyanobacteria/lichen crusted soil,， bareland and semishrub Ephedra distachya-inhabited site) from April to October of 2010 and 2011,， and NCF and dark respiration (DR) after four rainfall amounts (0， 2,， 5,， and 15 mm) in cyanobacteria/lichen crusted soil， bareland and the E. distachya-inhabited site. NCF in the E. distachya-inhabited site differed significantly from those of the other three soil cover types,， while no difference was observed between the moss and cyanobacteria/lichen crusted soils or between the two crusted soils and bareland on most measurement occasions. NCF ranged from 0.28 ± 0.14 to 1.2 ± 0.07 μmol m2 s1 in the biologically crusted soils,， and from 2.2 ± 0.27 to 0.46 ± 0.03 μmol m2 s1 at the E. distachya-inhabited site. Daily NCF in the biologically crusted soils and bareland showed carbon release at most times and total carbon production ranged from 48.8 ± 5.4 gC m2 yr1 to 50.9 ± 3.8 gC m2 yr1， while the E. distachya-inhabited site showed a total carbon uptake of 57.0 ± 9.9 gC m2 yr1. Daily variances in NCF were well-explained by variances in surface soil temperature,， and seasonal NCF showed a significant linear relationship with soil moisture in the two biologically crusted soils and bareland when soil volumetric water content was less than 3%. Rainfall elicited intense carbon release in cyanobacteria/lichen crusted soil,， bareland and at the E. distachya-inhabited site， and both NCF and DR were positive in the first two days after rainfall treatments. Mean NCF and DR were not different between rainfall amounts of 2,， 5 and 15 mm in cyanobacteria/lichen crusted soil and bareland,， while they were significantly higher after 15 mm rainfall treatment compared with 2 mm and 5 mm treatments at the E. distachya-inhabited site. Mean NCF and DR in the first two days increased logistically with rainfall amount. Based on our findings， we suggest that E. distachya-inhabited sites contribute to carbon uptake in the Gurbantunggute Desert,， while biologically crusted soils exhibit carbon release for most of the year. Even though photosynthesis immediately following rainfall can be stimulated,， carbon uptake effect in biologically crusted soil is likely intermittent and confined to periods when moisture is available.
