Analyzing the carbon dynamics of central European forests: comparison of Biome-BGC simulations with measurements

Biogeochemical models are often used for making projections of future carbon dynamics under scenarios of global change. The aim of this study was to assess the accuracy of the process-based biogeochemical model Biome-BGC for application in central European forests from the lowlands to upper treeline as a pre-requisite for environmental impact assessments. We analyzed model behavior along an altitudinal gradient across the alpine treeline, which provided insights on the sensitivity of simulated average carbon pools to changes in environmental factors. A second set of tests included medium-term (30 years) simulations of carbon fluxes, and a third set of tests focused on daily carbon and water fluxes. Model results were compared to aboveground biomass measurements, leaf area index recordings as well as net ecosystem exchange (NEE) and actual evapotranspiration (AET) measurements. The simulated medium-term forest growth agreed well with measured data. Also daily NEE fluxes were simulated adequately in most cases. Problems were detected when simulating ecosystems close to the upper timberline (overestimation of measured growth and pool sizes), and when simulating daily AET fluxes (overestimation of measured fluxes). The results showed that future applications of Biome-BGC could benefit much from an improvement of model algorithms (e.g., the Q₁₀ model for respiration) as well as from a detailed analysis of the ecological significance of crucial parameters (e.g., the canopy water interception coefficient).     

Integrated and comprehensive estimation of greenhouse gas emissions from land systems

Exchanges of carbon and nitrogen between the atmosphere and terrestrial ecosystems involve a complex set of interactions affected by both natural and management processes. Understanding these processes is important for managing ecosystem productivity and sustainability. Management processes also affect the net outcome of exchanges of greenhouse gases between terrestrial ecosystems and the atmosphere. In developing a national carbon accounting system (NCAS) for Australia to account for emissions and removal of greenhouse gases to and from the atmosphere, a carbon:nitrogen mass balance ecosystem model (FullCAM) was developed. The FullCAM model is a hybrid of empirical and process modelling. The approach enables application to a wide range of natural resource management issues, because it is at land-management-relevant spatial and temporal resolution and captures the main process and management drivers. The scenario-prediction capability can be used to determine the emissions consequences of different management activities. Because, in Australia, emissions of greenhouse gases are closely related to the retention of dead organic matter and the availability of nitrogen for plant growth, the carbon and nitrogen cycling as modelled are good indicators of ecosystem productivity and condition. The NCAS also emphasizes the advantages of a comprehensive and integrated approach to developing a continental scale ecosystem-modelling system that has relevance both to estimation of greenhouse gas emissions and sustainable management of natural resources.     

基于生态足迹分析的旅游地生态安全评价研究--以开封市为例

对旅游地生态安全状况进行评价具有熏要的理论意义和实践意义，根据生态足迹模型，构建了旅游地生态安全评价的指标体系和方法，并以人均旅游生态足迹和人均旅游用地承载力的比值Ⅰ来确定旅游地生态安全的状况。以开封市为研究区域，采用以上指标体系，对开封市2004年旅游生态安全状况进行了评价。研究结果表明：2004年开封市人均生态旅游足迹为0．014983hm^2，其中交通足迹最大，占到85．53％；其次是餐饮，为9．75％。人均旅游用地承载力为0．041790hm^2，生态安全度为0．36，处于一种一般状态或者说较为安全的状态。对研究结果采用旅游环境容量来进行判断，也表明研究结果较为准确地反映旅游地生态安全状况。     

On temperature and water limitation of net ecosystem productivity: Implementation in the C-Fix model

Monitoring, understanding and modelling carbon emission and fixation fluxes are key actions to guide climate change stakeholders in the application of mitigation strategies. In this study, we use the remote sensing model C-Fix at the local stand scale to improve the integration of algorithms for water and temperature limitation. These new algorithms are applied to estimate net ecosystem productivity in a fully water limited mode.     

Organic matter composition in sediments of the Oman Margin

The quantity and biochemical composition of organic matter (OM) in the sediments underlying and below oxygen minimum zone (OMZ) in the Arabian Sea were studied to provide information on the diagenetic processes of organic carbon under different environmental conditions. Concentrations of total organic carbon (TOC), total nitrogen (TN) and total hydrolysable amino acids (THAA) were significantly higher in sediments within rather than below OMZ, while those of total carbohydrates (TCHO) were slightly lower in the latter, suggesting the presence of a larger supply of labile compounds into the sea bottom at the shallower site (i.e. within OMZ). Hydrolysable amino acid and carbohydrate contribution to TOC were even lower (about 10% in surficial sediments) than the values obtained from the abyssal oligotrophic North Pacific, suggesting that OM food availability in the Oman Margin sediments within OMZ was lower than that observed at abyssal depths. The presence of the highest THAA and TCHO concentrations in the top 40 mm of the sediment core at both sites reflected the presence of bioturbation processes. In contrast with the general view of the deep sea as a stable and constant system, below OMZ in the Arabian Sea sediments, some differences were observed in the two investigated cores indicating the presence of a certain spatial variability in OM content and diagenesis.     

碳黑改性TiO2薄膜光催化剂的研制

通过掺杂碳黑来提高TiO2薄膜光催化剂的吸附性能，消除固定膜反应体系中经常出现的传质限制问题，使催化剂的活性由未经改性的3.2mg/L提高到4.8mg/L，相当于浓度为0.2g/L DegussaP25TiO2悬浮体系的效果，同时研究了影响催化剂活性的主要制备条件，获得的适宜制备条件为浓硝酸添加量1.0mL，热处理温度500℃，热处理时间2h，最佳涂覆次数为8次。     

城市节水“碳足迹”的探讨

随着水资源问题日益突出和城镇化的飞速发展,城市节水成为促进水资源可持续开发利用的有效措施。日益严峻的气候问题导致了人们对＂碳足迹＂的关注和低碳技术的发展。通过对城市节水相关因素＂碳足迹＂来源的分析,提出城市节水低碳化及建议。     

基于生态足迹方法的苏州市循环经济发展评价

依据生态足迹模型,计算了苏州市2004—2008年开展循环经济期间的生态足迹,并对其生态足迹多样性指数和可持续发展能力指标等进行分析。分析结果表明,自2004年推进循环经济以来,虽然苏州市生态足迹和生态赤字逐年增大,但是其年增长速度逐渐减小,发展模式正在向可持续发展方向转变。由于苏州的土地类型利用多样性不高,经济发展过度依赖能源的消耗,导致系统的发展能力受到限制,据此提出了苏州市进一步发展循环经济的对策建议。     

粘胶基活性炭纤维深度净化城市污水处理厂出水的实验研究

分别用粉状活性炭、粒状活性炭和粘胶基活性炭纤维处理污水处理厂出水,通过对水中COD、氨氮、浊度、pH值等指标进行对比实验,初步研究结果表明,活性炭纤维的吸附速率最快,达到吸附平衡所用时间最短,对水中COD吸附容量达124.6mg/g,浊度的去除率83%,但对氨氮、pH值无明显吸附效果。     

辽宁低碳经济的制约因素与应对策略

气候问题是人类价值所在,低碳经济是全球气候变化背景下中国的必然选择,发展低碳经济,符合国际发展的价值理念和趋势。在全球金融危机背景下,按照低碳经济的发展要求,分析辽宁发展低碳经济面临的主要障碍与制约因素,重点研究适合"低碳经济"要求的辽宁经济结构低碳化调整的应对策略,指出克服技术和资本的锁定效应是辽宁经济结构适应"低碳经济"调整的着力点,最后提出辽宁必须建立发展低碳经济的长效机制。