城乡复合系统生物地球化学代谢的系统生态学分析

发布时间：2018-06-01 20:41

  本文选题：城乡复合系统 + 系统生态学　； 参考：《浙江大学》2015年博士论文

【摘要】：在全球日益城市化的今天,人类对生态系统的影响已经从修饰上升为主导。人类对生态系统的改变极大地改善了人类的福祉,但同时也产生一系列环境问题,威胁人类健康和生态系统的健康。目前,全球已有超过半数人口居住在城市中,预计这个比例在2050年之前将达到70%,城市地区生物地球化学代谢与人类福祉的关系也将变得更加密切。城市绿地是与人类日常生活关系最密切的系统。它既可为人类提供生态服务,但同时也存在负面影响,例如排放生物源挥发性有机化合物(BVOC),可导致城市地区雾霾天气和臭氧污染。城市化地区与人类福祉关系密切的另一个组分是农业生产系统。作物种植和牲畜养殖在为人类提供食物的同时,也是大气氨和温室气体的主要排放源,既可导致区域性的大气雾霾,又能在全球水平影响气候变化。城市建成区及其毗邻的野外构成的城乡复合系统(urban-rural complex)的生物地球化学过程同时受到社会经济因素和自然环境因素的双重控制。只有采用系统生态学方法才能揭示这个复杂代谢系统的特征。然而,现有系统生态学模型在应用于城市研究时存在不足：一方面,现有模型多数基于对自然系统的研究,在进行系统分析时缺乏对人类因素的整合；另一方面,现有生物地球化学循环研究主要基于单一元素的质量平衡模型,因而无法刻画不同元素循环间存在的相互耦合。上述两方面的不足制约了人们对城乡复合系统的代谢开展综合分析与调控。本论文构建了系统生态学模型,该模型主要包含整合人类和自然因素的系统动力学子模型和可进行多元素协同分析的流平衡分析子模型。分别选择城市绿地和种植-养殖系统作为案例来进行系统生态学分析与调控。主要研究内容包括：在实验(城市植被调查和样品测定、排放速率测定等)的基础上,应用BVOC排放的系统动力学模型分析了杭州城市绿地BVOC排放的时空格局并探讨了人类和自然因素在决定BVOC排放中所扮演的角色；借鉴细胞代谢的系统生物学分析方法,对牛奶生产系统进行了碳、氢、氧、氮和磷五种元素的生物地球化学代谢网络重构,进而应用流平衡分析模型(FBA)对上海地区牛奶生产系统的代谢进行了多元素协同分析与优化。主要结论如下：(1)2010年,杭州城市绿地的BVOC排放总量为0.47 Gg C(95%置信区间为0.31-0.67 Gg C)。其中异戊二烯、单萜和其他种类VOC (OVOC)分别贡献了71.5%、20.2%和8.3%。城市绿地单位土地面积的BVOC排放强度(3.1 Mg C km-2yr-1)高于该地区的野外森林(2.7 Mg C km-2 yr-1 )。更大的平均树龄和更高的乔木密度使块状绿地排放强度(3.9 Mg C km-2 yr-1 )高于带状绿地(2.6 Mg C km-2 yr-1 )。与中国东部沿海的另外两个地区北京和香港作比较可发现,BVOC的排放强度呈现出随纬度降低而增加的规律。(2)杭州主要树种中单株排放潜力最高的为垂柳(1.21 kg C tree-1 yr-1)、枫香(0.80 kg C tree-1 yr-1)、合欢(0.45 kg C tree-1 yr-1)和悬铃木(0.35 kg C tree-1 yr1) 。杭州本地种和外来种的BVOC排放潜力间没有显著差异,这更新了之前外来树种排放高于本地种的结论。原因可能是由于以往的结果是在温带地区得到的,本研究是位于亚热带的杭州,其引入的外来观赏树种同样起源于其他亚热带地区,分类学关系上较为接近。在绿地中,人类对景观植物的偏好造成树种构成相对单一(物种多样性低),加之各树种间的BVOC排放潜力差异巨大,使得仅香樟、悬铃木、垂柳和枫香四个树种就贡献了杭州城市绿地BVOC总排放的75%以上。(3)模拟结果表明,杭州城市绿地BVOC排放具有明显的日变化。异戊二烯的排放主要发生在白天,峰值出现在午后14时；单萜和OVOC日夜均有排放,日变化相对较小。BVOC排放的季节差异明显,夏季的排放最大,占到全年总排放的67%,冬季排放最少,仅占不到全年的2%。人类因素对BVOC排放的日动态和季节动态的影响较小,其动态主要受长期(物候)和短期(温度、光照强度、CO2浓度)的自然环境因素的控制。(4)在所有环境变化(全球变暖、热岛效应、PAR改变、CO2浓度升高)和人类管理情景下(绿地面积扩张、调节新栽和已有树木的树种比例、改变乔木密度),城市绿地总BVOC排放都表现出快速增长的趋势,从2010年0.47 Gg C增长到2050年的1.2-3.2 Gg C,增幅为155%-580%,远高于野外森林排放的增长速度。这意味着城市绿地已成为重要的VOC排放源,对区域空气质量的影响也将越来越大。与基线情景相比(只考虑树木生长),管理因素对未来BVOC排放的改变幅度(-32%-70%)大于环境因素(-12%-30%),表明人类因素在决定未来城市BVOC排放时扮演了更为重要的角色,也凸显出将人类因素纳入模型的重要性。管理策略对BVOC排放的影响具有时滞效应,不同策略下的BVOC排放在最开始几年可能差异很小,但随着时间的推移差异越来越大,这要求管理者在制定策略时要更具前瞻性。(5)本论文提出用叶生物量/BVOC排放的比值作为衡量绿地生态系统服务价值高低的标准。模型分析的结果表明：通过积极应对环境变化并采用前瞻性的城市管理策略(即适度增加乔木密度、限制绿地面积的扩张以及优化已有树木和新栽种树木的树种组成)可以在未来(2050年)获得最高的生态系统服务价值(叶生物量/BVOC比值为39.9)；消极应对环境改变以及盲目的发展(城市绿地的无序扩张、不适宜的树种选择)将极大限制绿地所提供的生态服务价值(叶生物量/BVOC比值为20.8)。城市管理中应给予BVOC排放足够的重视,充分考虑城市绿地正负服务之间的权衡。(6)通过生态系统代谢重构,整个牛奶生产系统的生物地球化学代谢可用191个代谢物参与的277个代谢方程式表达,例如将大豆籽粒加工的过程表达为100大豆籽粒-85豆饼+10豆油+5大豆加工损失。把代谢物和反应控制器作为节点,并根据节点的相互转化关系用边进行连接可进一步得到整个牛奶生产系统的代谢网络。代谢网络包含468个节点(191个代谢物和277个反应控制器)和1165条边。节点的平均度数为4.98。节点的度数分布符合幂律分布,因此这个网络与因特网、社会网络一样,也是无标度(scale-free)网络。牛奶生产系统代谢网络的直径为16,平均最短路径长度为5.8,具有“小世界”的特征。(7)上海地区牛奶生产系统在满足人类营养需求的同时对环境健康和人类健康均造成了损害。根据重构代谢网络的流分布结合生命周期环境影响评估,2010年上海每生产1吨牛奶共向大气排放了629.5 kg的CO2、43.7 kg CH4、15.7 kg CO、 4.1 kg NOx、1.8kg N2O、1.0kg NH3、3.3 kg PM和0.6 kg NMVOC;向水体排放了16.0 kg氮和2.0 kg的磷；同时消耗了47.6吨水、106.0 kg初级能源(以标准煤计)和0.7kg的矿物磷(以P计)。将这些资源和环境影响货币化后,相当于造成了环境损害成本3500元ton-1 milk,其中对人类健康损害占45%,对生态系统健康的损害占52%,对资源的损害占3%。(8)在牛奶生产系统中,对碳循环的优化和对氮、磷循环的优化之间均存在权衡关系,而氮循环的优化与磷循环的优化之间存在协同关系。当以碳元素为优化目标时,与碳相关的环境影响下降了23.2%,然而此时,与氮循环和磷循环相关的环境影响却恶化了,氮和磷的环境损害成本分别增加了12.3%和13.9%；当以氮元素为优化目标时,氮相关的环境影响下降了25.8%,与此同时与磷循环相关的环境影响同步改善了18.2%,与碳循环相关的环境影响却恶化了,其环境成本增加了19.2%。碳、氮元素的优化之间存在权衡的原因是很多减少氮素向水体和大气排放的措施(例如农田施用缓释、控释氮肥,提高粪便处理率等)都要消耗大量的化石能源,而化石燃料的使用增加了CO2、CO、VOC等碳相关气体的排放。而减少氮向水体排放的措施同时也可以减少磷向水体的排放,这造成了N、P之间的协同。(9)对任意两个环境排放或资源消耗类别进行两两相关分析得到的78对环境影响中,33对显著相关(p0.05)。其中,权衡强度最大的为磷向水体的排放和VOC排放、氮向水体的排放和VOC排放,权衡强度均为-0.81(线性回归的R值)；C02排放和VOC排放具有最强的协同,协同系数为0.97。(10)通过系统生态学可实现多元素协同分析与优化,在很大程上减弱权衡,利用协同,实现更为综合的管理和优化。当综合考虑各项环境影响并以减少系统总的环境损害成本作为优化目标时,牛奶生产系统的总环境成本比基线情景(2012年上海生产实践)下降了22.4%,各项环境影响均得到了不同程度的改善。而以单元素作为优化目标时,环境成本仅下降了3.7%-17.4%,远不及多元素协同优化的效果。在实际管理中,决策者可根据需要选取要优化的项目并设置权重实现综合的优化,这是无法通过对单一元素进行分别优化而实现的。
[Abstract]:In today's increasingly urbanized world, the impact of human beings on the ecosystem has been dominated by the rise of the ecosystem, and human well-being has been greatly improved by the human ecosystem, but at the same time a series of environmental problems have been created to threaten the health of human health and the health of the ecosystem. It is expected to reach 70% by 2050, and the relationship between biogeochemical metabolism and human well-being will become closer in urban areas. Urban green space is the most closely related system to human daily life. It can provide ecological services for human beings, but there are also negative impacts, such as the emission of volatile organic compounds from biological sources. Compounds (BVOC) can lead to haze and ozone pollution in urban areas. Another component of urbanization areas closely related to human well-being is the agricultural production system. Crop planting and livestock breeding are also the main source of atmospheric ammonia and greenhouse gases, which can lead to regional haze and haze, as well as to provide food for human beings. The biogeochemical process of the urban and rural complex system (urban-rural complex) formed in the urban built-up area and its adjacent field is controlled by both socioeconomic factors and natural environmental factors. Only systematic ecological methods can be used to reveal the characteristics of this complex metabolic system. On the one hand, most of the existing models are based on the study of natural systems and lack the integration of human factors in the systematic analysis. On the other hand, the existing biogeochemical cycle studies are mainly based on the mass balance model of a single element, and thus can not be carved. In this paper, a system ecology model is constructed, which mainly includes the system dynamics model of integrating human and natural factors and the flow of multi element synergy analysis in the two aspects. On the basis of the experiment (urban vegetation survey and sample measurement, emission rate measurement and so on), the system dynamics model of BVOC emission was used to analyze the urban green space BVOC in Hangzhou. The spatial and temporal pattern of emission and the role of human and natural factors in determining BVOC emissions are discussed. The biological geochemical metabolic network of five elements of carbon, hydrogen, oxygen, nitrogen and phosphorus is rebuilt for the milk production system by using the systematic biological analysis method of cell metabolism, and then the flow equilibrium analysis model (FBA) is applied to the Shanghai land. Multi element synergetic analysis and optimization were carried out in the metabolism of the dairy production system. The main conclusions were as follows: (1) the total BVOC emission of urban green space in Hangzhou was 0.47 Gg C (95% confidence interval 0.31-0.67 Gg C) in 2010. The isoprene, monoterpenes and other kinds of VOC (OVOC) contributed to the land surface of the urban green space unit of 20.2% and 8.3%.. The accumulated BVOC emission intensity (3.1 Mg C km-2yr-1) is higher than that in the field forest (2.7 Mg C KM-2 yr-1). Greater average tree age and higher tree density make the emission intensity of the massive green space (3.9 Mg C KM-2 yr-1) is higher than that of the belt (2.6). Compared with the other two regions of the East China coast, Beijing and Hongkong can be compared. At present, the emission intensity of BVOC increases with the decrease of latitude. (2) the highest potential of single plant emission in Hangzhou's main tree species is the vertical willow (1.21 kg C tree-1 yr-1), maple (0.80 kg C tree-1 yr-1), acacia (0.45 kg C tree-1) and the suspension tree (0.35). There is a significant difference, which updates the previous conclusion that the emission of foreign species is higher than that of the native species. The reason may be that the previous results were obtained in the temperate region. This study was located in the subtropical Hangzhou. The introduction of exotic ornamental tree species also originated in other subtropical regions and was closer to the taxonomic relationship. The preference of landscape plants resulted in a relatively single species composition (low species diversity), and the BVOC emission potential difference between the various species was huge, which made the four species of camphor, camphor, weeping willow and maple incense contributed more than 75% of the total emission of the urban green space in Hangzhou. (3) the simulation results showed that the emission of BVOC in urban green space in Hangzhou has a distinct day. The emission of isoprene mainly occurred in the daytime and peak in the afternoon 14; monoterpene and OVOC were discharged in the day and night, and the daily variation of the diurnal variation relatively small.BVOC emission was obvious, the summer emission was the largest, which accounted for 67% of the total emissions in the whole year, the winter emission was least, and the daily dynamics of the 2%. human factors that were less than the whole year were only less than the daily dynamics of BVOC emissions. Seasonal dynamics are less affected, and their dynamics are mainly controlled by the natural environmental factors of long-term (phenological) and short-term (temperature, light intensity, CO2 concentration). (4) in all environmental changes (global warming, heat island effect, PAR change, CO2 concentration) and human management landscape (the expansion of green area, the proportion of new trees and tree species, Variable tree density), the total BVOC emission of urban green space shows a rapid growth trend, increasing from 0.47 Gg C in 2010 to 1.2-3.2 Gg C in 2050, increasing to 155%-580%, which is far higher than the growth rate of field forest emissions. This means that urban green space has become an important source of VOC emission, and the effect on regional air quality will become more and more large. The change range of management factors to future BVOC emissions (-32%-70%) is greater than that of environmental factors (-12%-30%), indicating that human factors play a more important role in determining future urban BVOC emissions, and it also highlights the importance of incorporating human factors into the model. Management strategies have an impact on BVOC emissions. Time lag effect, BVOC emissions under different strategies may have little difference in the first few years, but as time goes on, the difference is becoming more and more, which requires managers to be more forward-looking when making strategies. (5) this paper proposes that the ratio of /BVOC emission by leaf biomass is the standard to measure the service value of green ecosystem services. The results showed that the highest biomass system service value (leaf biomass /BVOC ratio was 39.9) could be obtained in the future (2050) by actively responding to environmental changes and adopting prospective urban management strategies (i.e., moderately increasing tree density, limiting the expansion of green area and optimizing the composition of trees and new tree species). Negative response to environmental changes and blind development (the unordered expansion of urban green space, unsuitable selection of tree species) will greatly limit the ecological service value provided by green space (the ratio of leaf biomass /BVOC is 20.8). In urban management, BVOC emission should be given enough attention to consider the trade-off between positive and negative services of urban green space. (6) through life. Metabolic remodeling of the state system, the biogeochemical metabolism of the whole milk production system can be expressed in 277 metabolic equations involving 191 metabolites. For example, the process of processing soybean seeds is expressed as 100 soybean seed -85 bean cake +10 soybean oil +5 soybean processing loss. The transformation relationship is connected by the edge to further get the metabolic network of the whole milk production system. The metabolic network consists of 468 nodes (191 metabolites and 277 reaction controllers) and 1165 sides. The degree distribution of the node's degree is 4.98. nodes in the power law distribution, so the network is the same as the Internet, the social network, as well. The scale-free network. The diameter of the metabolic network in the milk production system is 16 and the average shortest path length is 5.8. (7) the milk production system in Shanghai has caused damage to both the environmental health and the human health while meeting the human nutritional requirements. Life cycle environmental impact assessment. In 2010, 1 tons of milk produced in Shanghai produced a total of 629.5 kg of CO2,43.7 kg CH4,15.7 kg CO, 4.1 kg NOx, 1.8kg N2O, 1.0kg NH3,3.3, and 0.6 phosphorous; and 47.6 tons of water, 106 primary energy (standard coal) and mineral deposits were consumed at the same time. Phosphorus (P). After monetization of these resources and environmental impacts, the cost of environmental damage was 3500 yuan ton-1 milk, which accounted for 45% of the human health damage, 52% of the damage to the ecosystem health, and the damage to the resources was 3%. (8) in the milk production system, the optimization of carbon cycle and the optimization of nitrogen and phosphorus cycle were all stored in the milk production system. In the tradeoff, there is a synergistic relationship between the optimization of nitrogen cycle and the optimization of the phosphorus cycle. When the carbon element is the optimal target, the environmental impact of the carbon related environment is reduced by 23.2%. However, the environmental effects associated with the nitrogen cycle and phosphorus cycle are deteriorating, and the environmental damage costs of nitrogen and phosphorus are increased by 12.3% and 13.9%, respectively. When nitrogen was optimized, the nitrogen related environmental impact decreased by 25.8%, while the environmental impact associated with the phosphorus cycle improved by 18.2%. The environmental impact associated with the carbon cycle was deteriorated, the environmental cost was increased by 19.2%. carbon. The trade-off between nitrogen elements was due to the reduction of nitrogen to the water and the atmosphere. The measures of emission (such as slow release of farmland, controlled release nitrogen fertilizer, increase of fecal treatment rate, etc.) consume a large amount of fossil energy, while the use of fossil fuels increases the emission of carbon related gases such as CO2, CO, VOC and so on. The measures to reduce nitrogen to the water body can also reduce the emission of phosphorus to the water body, which leads to the synergy between N and P. (9) 33 of the 78 pairs of environmental impacts on any two environmental emission or resource consumption categories were significantly correlated (P0.05). Among them, the balance intensity was -0.81 (the R value of linear regression), and C02 emission and VOC emission. With the strongest synergy and synergistic coefficient of 0.97. (10), multi element Co analysis and optimization can be realized through system ecology. The trade-off is reduced on a large scale and synergy is used to achieve more comprehensive management and optimization. When the environmental impact is considered and the total environmental damage cost of the system is reduced as an optimization goal, the milk production system The total environmental cost is lower than the baseline scenario (Shanghai production practice in 2012) by 22.4%. All the environmental impacts have been improved in varying degrees. When the single element is used as the optimization target, the environmental cost is only reduced by 3.7%-17.4%, far less than the effect of multi element synergy optimization. In the actual management, the decision-makers can choose to optimize according to the needs. The project and set weights to achieve comprehensive optimization, which can not be achieved by optimizing single elements separately.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：Q147
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本文编号：1965560