末次盛冰期以来中国陆地生态系统碳储量变化研究

Carbon is an essential element for life, food and energy. It is also a key element in the greenhouse gases and therefore plays a vital role in climatic changes. The rapid increase in atmospheric concentration of CO_2 over the past 150 years, reaching current concentrations of about 370 ppmv, corresponds with combustion of fossii fuels since the beginning of the industrial age. Conversion of forested land to agricultural use has also redistributed carbon from plants and soils to the atmosphere. These human activities have significantly altered the global carbon cycle. Understanding the consequences of these activities in the coming decades is critical for formulating economic, energy, technology, trade, and security policies that will affect civilization for generations. Under the auspices of the International Geosphere-Biosphere Programme (IGBP), several large international scientific efforts are focused on elucidating the various aspects of the global carbon cycle of the past decade. It is only possible to balance the global carbon cycle for the 1990s if there is net carbon uptake by terrestrial ecosystems of around 2 Pg C/a. There are now some independent, direct evidences for the existence of such a sink. Policymarkers involved in the UN Framework Convention on Climate Change (UN-FCCC) are striving to reach consensuses on a 'safe path' for future emissions, the credible predictions on where and how long the terrestrial sink will either persist at its current level, or grow/decline in the future, are important to advice the policy process. The changes of terrestrial carbon storage depend not only on human activities, but also on biogeochemical and climatological processes and their interaction with the carbon cycles. In this thesis, the climate-induced changes and human-induced changes of carbon storage in China since the past 20,000 years are examined. Based on the data of the soil profiles investigated during China's Second National Soil Survey (1979-1989), the forest biomass measured during China's Fourth National Forest Resource Inventory (1989-1993), the grass biomass investigated during the First National Grassland Resource Survey (1980-1991), and the data collected from a collection of published literatures, the current terrestrial carbon storage in China is estimated to -144.1 Pg C, including -136.8 Pg C in soil and -7.3 Pg C in vegetation. The soil organic (SOC) and inorganic carbon (SIC) storage are -78.2 Pg C and -58.6 Pg C, respectively. In the vegetation reservoir, the forest carbon storage is -5.3 Pg C, and the other of-1.4 Pg C is in the grassland. Under the natural conditions, the SOC, SIC, forest and grassland carbon storage are -85.3 Pg C, -62.6 Pg C, -24.5 Pg C and -5.3 Pg C, respectively. Thus, -29.6 Pg C organic carbon has been lost due to land use with a decrease of -20.6%. At the same time, the SIC storage also has been decreased by -4.0 Pg C (-6.4%). These suggest that human activity has caused significant carbon loss in terrestrial carbon storage of China, especially in the forest ecosystem (-76% loss). Using the Paleocarbon Model (PCM) developed by Wu et al. in this paper, total terrestrial organic carbon storage in China in the Last Glacial Maximum (LGM) was -114.8 Pg C, including -23.1 Pg C in vegetation and -86.7 Pg C in soil. At the Middle Holocene (MH), the vegetation, soil and total carbon were -37.3 Pg C, -93.9 Pg C and -136.0 Pg C, respectively. This implies a gain of-21.2 Pg C in the terrestrial carbon storage from LGM to HM mainly due to the temperature increase. However, a loss of-14.4 Pg C of terrestrial organic carbon occurred in China under the current condition (before 1850) compared with the MH time, mainly due to the precipitation decrease associated with the weakening of the Asian summer monsoon. These results also suggest that the terrestrial ecosystem in China has a substantial potential in the restoration of carbon storage. This might be expected to provide an efficient way to mitigate the greenhouse warming through land management practices. Assuming that half of the carbon loss in the degraded terrestrial ecosystem in current forest and grass areas are restored during the next 50 years or so, the terrestrial ecosystem in China may sequestrate -12.0 Pg of organic carbon from the atmosphere, which represents a considerable offset to the industry's CO2 emission. If the ' Anthropocene' Era will be another climate optimum like MH due to the greenhouse effect, the sequestration would be increased again by -4.3 - 9.0 Pg C in China.

一种由全球水循环产生的可能重要的CO2汇

关于全球CO2汇的位置、大小、变化和机制目前仍不确定, 还存有争议. 在理论计算和野外观测数据证明的基础上发现, 可能存在一种由全球水循环产生的重要的CO2汇(以溶解无机碳-DIC的形式). 这个汇达到0.8013 Pg C/a(约占人类活动排放CO2总量的10.1%, 或占所谓的遗漏CO2汇的28.6%), 它是由水对CO2的溶解吸收形成的, 并随着碳酸盐的溶解及水生植物光合作用对CO2的消耗的增加而显著增加. 这部分汇中有0.5188 Pg C/a通过海上降水(0.2748 Pg C/a)和陆地河流(0.244 Pg C/a)进入海洋, 有0.158 Pg C/a再次释放进入大气, 还有0.1245 Pg C/a储存在陆地水生生态系统中. 因此, 净沉降是0.6433 Pg C/a. 随着全球变暖引起的全球水循环的加强、CO2和大气圈中碳酸盐粉尘的增加, 还有造林地区的增多(会引起土壤CO2的增加进而导致水中DIC浓度的增大), 这部分汇也可能增加.

超临界CO2流体萃取重金属的研究进展

超临界CO2流体与技术配合相结合开辟了重金属萃取的新途径。本文介绍了超临界CO2流体萃取重金属的研究现状，总结了影响萃取的因素，并对未来的发展趋势作了展望。

岩溶水系统对大气CO2的潜在影响——基于热力学的研究

认识不同条件下岩溶水释放或吸收CO2 的反应过程是研究碳酸盐岩对碳循环响应的前提和基础。本文从吉布斯自由能的热力学原理出发,对全球不同岩溶地区162 组岩溶水(河水、溪水、湖水等) 进行了热力学研究,结果显示:1) 河水、溪水、湖水和洞穴滴水等岩溶水所处的环境因方解石矿物沉积而释放CO2 成为大气CO2 一个潜在的源;2) 地下水在所处的环境下由于方解石的溶解而吸收CO2 ,成为大气CO2 一个潜在的汇;3) 少数出露点的泉水所处的环境既可发生方解石的溶解而吸收CO2 ,成为大气CO2 的潜在汇,也可发生方解石的沉积而释放CO2 ,成为大气CO2 的潜在源;4) 在洪水期,泉水的水化学特征变化并未导致对大气CO2 潜在贡献在源汇之间的跨跃性转变。162 组岩溶水数据中,所有河水与溪水皆无一例外地在释放CO2 。结果表明,从吉布斯自由能的热力学原理出发,研究岩溶水系统对大气CO2 潜在源汇的贡献,没有条件约束,是一种较好的途径。

超临界CO2萃取小茴香精油与其它方法所得提取物的成分对比

本文主要是研究超临界CO2萃取小茴香精油的GC－MS成分，并将其与水蒸汽蒸馏产物及索氏提取产物相对比。分析结果表明：超临界CO2萃取精油与水蒸汽蒸馏提取物、索氏提取物的主要差异在于脂肪酸的含量。超临界CO2萃取小茴香精油的主要成分为大茴香脑和脂肪酸，而水蒸汽蒸馏及索氏提取物的主要成分为大茴香脑。

超临界CO2萃取九叶青花椒和大红袍花椒挥发油的化学成分分析及香气比较

采用超临界CO2萃取法提取九叶青花椒和大红袍花椒挥发油，以气相色谱-质谱仪对其化学成分进行检测，用色谱峰面积归一化法确定各化学成分的相对含量，评香师对花椒挥发油的香气进行评价。结果表明，超临界萃取的九叶青花椒挥发油得率为7％，鉴定出63个化合物，属青香型花椒油；超临界萃取的大红袍花椒挥发油得率为4％，鉴定出80个化合物，属浓香型花椒油；两种花椒挥发油的化学成分含量和香气有明显差异，但都保留了各自品种的天然香气特征.

超临界CO2萃取灵芝孢子油的GC／MS分析

采用超临界CO2萃取破壁灵芝孢子，萃取条件22MPa，40℃，将所得的孢子油，经GC／MS定性和定量分析，共检出18种脂肪酸成分，其中亚油酸和油酸占62．45％，不饱和脂肪酸占68．42％。

我国南方岩溶区和北方黄土区的大气CO2效应

我国南方岩溶区与北方黄土区都是巨大的碳库。碳酸盐的溶蚀及再结晶是两个碳库与大气ＣＯ２交换的重要过程；碳的区域平衡是评价化学风化消耗或逸散ＣＯ２的基础，岩溶区与黄土区在地球化学风化的环境背景。溶蚀过程，产物运移和归宿等差异很大。黄土区化学风化消耗大气ＣＯ２通量较岩溶区小。目前评价两类地区土壤与大气ＣＯ２的源汇关系尚不成熟，需要定量认识土壤ＣＯ２与下伏碳酸盐岩溶蚀或与下伏黄土次生碳酸盐化作用。

云贵高原湖泊CO2的地球化学变化及其大气CO2源汇效应

国家自然科学基金项目(批准号：49903007和40073032)和中国科学院知识创新工程项目(批准号：KZCX2—105)资助

超临界CO2萃取印楝种子中印楝素的研究

应用超临界CO2 萃取技术从印楝种子中萃取印楝素,研究了萃取温度、压力和夹带剂对印楝素萃取效果的影响。当萃取温度为35 ℃、压力为15 MPa、甲醇用量为CO2 体积的3 %时,可将印楝种子中90 %以上的印楝素A 萃取出来,所得产品印楝素A 的质量分数为2013 %。

超临界CO2萃取不同部位姜油的组成研究

应用超临界CO2萃取同一品种生姜的带皮姜、去皮姜、姜皮姜油，采用GC-MS联用技术分离鉴定其中的化学组成，并计算其相对含量。结果表明不同部位姜油化学成分含量存在差异。

大蒜深加工中的超临界CO2萃取技术

介绍了大蒜的重要用途及大蒜油的几种主要提取技术,综述了超临界CO2 萃取技术在大蒜深加工中大蒜油提取、大蒜脱臭及生物活性成分保留方面的应用研究。

超临界CO2萃取花椒挥发油及化学组分研究

用超临界CO2萃取技术提取重庆江津产青花椒挥发油，研究了萃取温度的影响，用色谱－质谱联用仪分析了花椒挥发油化学成分及百分含量，共鉴定出38个化合物，占挥发油总量的98.81%，其中花椒挥发油的特征有效成分之一－哩哪醇含量高达58.79%，表明用超临界CO2萃取技术提取重庆江津产青花椒挥发油品质较高。

超临界CO2萃取精馏EPA与DHA的实验研究

采取超临界CO2萃取-精馏技术，对经尿素包合预处理的鱼油脂肪酸乙酯在超临界CO2流体中的溶解情况进行了考察，探索了EPA、DHA的分离提纯工艺，并讨论了实验的影响因素。实验结果表明：采用温度梯度结合逐步升压法，能使鱼油脂肪酸乙酯按碳链长度依次分离，EPA+DHA提纯至90%，两次分离后，EPA提纯至67%，DHA提纯至90%以上。