Biological soil crusts （BSCs） are an important type of land cover in arid desert landscapes and play an important role in the carbon source-sink exchange within a desert system. In this study, two typical BSCs, moss...Biological soil crusts （BSCs） are an important type of land cover in arid desert landscapes and play an important role in the carbon source-sink exchange within a desert system. In this study, two typical BSCs, moss crusts and algae crusts, were selected from a revegetated sandy area of the Tengger Desert in northern China, and the experiment was carried out over a 3-year period from January 2010 to November 2012. We obtained the effec- tive active wetting time to maintain the physiological activity of BSCs basing on continuous field measurements and previous laboratory studies on BSCs photosynthesis and respiration rates. And then we developed a BSCs carbon fixation model that is driven by soil moisture. The results indicated that moss crusts and algae crusts had significant effects on soil moisture and temperature dynamics by decreasing rainfall infiltration. The mean carbon fixation rates of moss and algae crusts were 0.21 and 0.13 g C/（m2.d）, respectively. The annual carbon fixations of moss crusts and algae crusts were 64.9 and 38.6 g C/（m2.a）, respectively, and the carbon fixation of non-rainfall water reached 11.6 g C/（m2.a） （30.2% of the total） and 8.8 g C/（m2.a） （43.6% of the total）, respectively. Finally, the model was tested and verified with continuous field observations. The data of the modeled and measured CO2 fluxes matched notably well. In desert regions, the carbon fixation is higher with high-frequency rainfall even the total amount of seasonal rainfall was the same.展开更多
In order to improve man-made biological soil crusts (BSCs) for desertification control and develop value-added utilization of bioenergy byproducts, preliminary experiments were carried out to understand the effect of ...In order to improve man-made biological soil crusts (BSCs) for desertification control and develop value-added utilization of bioenergy byproducts, preliminary experiments were carried out to understand the effect of biochar addition on algae growth in sand. Microcoleus vaginatus was chosen as the model algae and cultivated in sand with various contents of biochar (0%, 2%, 5%, 8%, and 10% weight of sand) that were made by rice hull gasification. Results showed that when the content of biochar in sand was 2%, both algal biomass (indicated by chlorophyll-a content) and the fixed sand weight in the BSC were significantly higher than that of the control (without biochar addition) and other treatments (with >2% biochar additions). Results from this pioneering research indicate that appropriate amount of biochar addition could increase BSC formation in sand under dry conditions and can potentially enhance sand fixation in deserts for desertification control.展开更多
基金supported by the Knowledge Innovation Project of the Chinese Academy of Sciences (KZCX2-EW-301-3)the National Program on Key Basic Research Project (2013CB429905)+1 种基金the National Natural Scientific Foundation of China (41201084 31170385)
文摘Biological soil crusts （BSCs） are an important type of land cover in arid desert landscapes and play an important role in the carbon source-sink exchange within a desert system. In this study, two typical BSCs, moss crusts and algae crusts, were selected from a revegetated sandy area of the Tengger Desert in northern China, and the experiment was carried out over a 3-year period from January 2010 to November 2012. We obtained the effec- tive active wetting time to maintain the physiological activity of BSCs basing on continuous field measurements and previous laboratory studies on BSCs photosynthesis and respiration rates. And then we developed a BSCs carbon fixation model that is driven by soil moisture. The results indicated that moss crusts and algae crusts had significant effects on soil moisture and temperature dynamics by decreasing rainfall infiltration. The mean carbon fixation rates of moss and algae crusts were 0.21 and 0.13 g C/（m2.d）, respectively. The annual carbon fixations of moss crusts and algae crusts were 64.9 and 38.6 g C/（m2.a）, respectively, and the carbon fixation of non-rainfall water reached 11.6 g C/（m2.a） （30.2% of the total） and 8.8 g C/（m2.a） （43.6% of the total）, respectively. Finally, the model was tested and verified with continuous field observations. The data of the modeled and measured CO2 fluxes matched notably well. In desert regions, the carbon fixation is higher with high-frequency rainfall even the total amount of seasonal rainfall was the same.
文摘In order to improve man-made biological soil crusts (BSCs) for desertification control and develop value-added utilization of bioenergy byproducts, preliminary experiments were carried out to understand the effect of biochar addition on algae growth in sand. Microcoleus vaginatus was chosen as the model algae and cultivated in sand with various contents of biochar (0%, 2%, 5%, 8%, and 10% weight of sand) that were made by rice hull gasification. Results showed that when the content of biochar in sand was 2%, both algal biomass (indicated by chlorophyll-a content) and the fixed sand weight in the BSC were significantly higher than that of the control (without biochar addition) and other treatments (with >2% biochar additions). Results from this pioneering research indicate that appropriate amount of biochar addition could increase BSC formation in sand under dry conditions and can potentially enhance sand fixation in deserts for desertification control.
