Net Ecosystem Production of Boreal Larch Ecosystems on the Yenisei Transect

The study was carried out in the Turukhansk Research Station of Yenisei Transect (65^°46^′N, 89^°25^′E). Larch (Larix gmelinii (Rupr.) Rupr.) is the dominant overstory tree species. The research has been conducted on four permanent test plots in same-age mature (110-year old) and overmature (380-year old) post-fire larch stands of green moss and lichen groups of forest type. Carbon cycle parameters were assessed based on a biometric method. Quantitative analysis of carbon pools and fluxes shows that net ecosystem production of north taiga larch stands averages 32% of net primary production. Sink of atmospheric CO₂ makes 1.22 and 0.74 t C ha^{− 1} year^{− 1} for mature and overmature green moss larch stands, and 0.65 and 0.35 t C ha^{− 1} year^{− 1} for lichen type. Net carbon sink in the tree layer make up 9% of net primary production carbon, ground vegetation – 15%, and dead plant residues accumulation – 8% of atmospheric carbon uptake via photosynthesis.     

海洋碳的源与汇

通过对海洋碳源汇最近研究成果的分析,剖析了海洋碳源汇的内涵,提出了“表观碳源汇”与“实际碳源汇”的概念,对海洋碳源汇不确定性的原因进行分析,提出碳参数测定不淮确与其关键生物地球化学过程不清楚是其根本原因,继而提出了海洋碳源汇研究应特别注重陆架边缘海碳循环过程研究,提高碳参数测定的淮确性和应深入研究控制碳循环关键的海洋生物地球化学过程是其研究关键。     

Fossil carbon emissions associated with carbon flowsof wood products

Specific fossil carbon (C) emissions and primary energy useassociated with the manufacture of different wood product groups inFinland are estimated and expressed as emissions or energy use per amountof wood-based C in raw material and per amount in end product. Thecalculation includes both emissions from supplied fuels within the forestindustries, and from electricity and district heat purchased from externalsources. The results are compared to fossil C emissions from the wholelifecycle of harvested wood products. The results of the study show, forinstance, that the emission of fossil C per wood-based C in end products(MgC/MgC) is of the order of 0.07 for sawn wood and 0.3–0.6 for paperin the manufacturing stage. The primary energy use per wood-based C inend product is of the order of 2 MWh/MgC for sawn wood, whereas forvirgin paper grades the figure is between 17 and 19 MWh/MgC. Theprimary energy content is highest in papers based on chemical pulping, butaround 60% of the energy used is produced in this case from by-productwood wastes (black liquor, bark etc.). The specific fossil C emission andprimary energy divided by the estimated service life of the wood productare measures for the relative burden of maintaining the corresponding woodproduct pool. These figures should be kept in mind when considering woodproducts as a potential C sink option.     

概论N_2O大气浓度演变及其大气化学

N2 O在对流层中是长寿命的痕量温室气体 ;在平流层 ,它是破坏O3层主要痕量气体之一NO的生成源。本文主要综述了N2 O的大气浓度演变、大气寿命、对温室效应的贡献、大气化学等 ,着重探讨了可能存在的N2 O大气生成和消耗过程     

全球变化下有关卤代甲烷源汇的研究进展

大气中存在的卤代甲烷对臭氧层具有极强的破坏作用并参与其它气候现象，其动态变化对臭氧的恢复和地球生态系统有重要影响。文章概述了全球变化下卤代甲烷源汇的研究情况并简单探索其进一步的研究方向。几种卤代甲烷中，溴代甲烷源汇最复杂且对臭氧具有最强的破坏力，因此研究较多。已证明CH3Br的来源有：海洋、土壤、生物燃烧、陆地植物和沼泽地的释放等；CH3Br的汇包括：光化学分解、被土壤和植物吸收、在海洋中的化学和生物降解等。但事实上是已知汇远远大于已知源，且各个源汇的通量在不同研究中结果差异较大，归其原因是卤代甲烷释放与吸收机制的不确定性。虽然近几年的研究也应用了稳定同位素示踪技术，但卤代甲烷各源汇的具体贡献并不清楚。今后卤代甲烷源汇的研究重点应放在与气体产生机制最密切的地下部分即“地下生态学”对其通量的影响，而同位素技术的改进及其在痕量气体研究中的应用也将是未来的重点方向。     

Ten years of atmospheric methane observations at a high elevation site in Western China

In this paper, the continuous (1994–2001) and discrete air sample (1991–2001) measurements of atmospheric CH₄ from the Waliguan Baseline Observatory located in western China (36°17′N, 100°54′E, 3816 m asl) are presented and characterized. The CH₄ time series show large episodic events on the order of 100 ppb throughout the year. During spring, a diurnal cycle with average amplitude of 7 ppb and a morning maximum and late afternoon minimum is observed. In winter, a diurnal cycle with average amplitude of 14 ppb is observed with an afternoon maximum and morning minimum. Unlike most terrestrial observational sites, no obvious diurnal patterns are present during the summer or autumn. A background data selection procedure was developed based on local horizontal and vertical winds. A selected hourly data set representative of “baseline” conditions was derived with approximately 50% of the valid hourly data. The range of CH₄ mixing ratios, annual means, annual increases and mean annual cycle at Waliguan during the 1992–2001 were derived from discrete and continuous data representative of “baseline” conditions and compared to air samples collected at other Northern Hemisphere sites. The range of CH₄ monthly means of 1746–1822 ppb, average annual means of 1786.7±10.8 ppb and mean annual increase of 4.5±4.2 ppb yr⁻¹ at Waliguan were inline with measurements from sites located between 30° and 60°N. There were variations observed in the CH₄ annual increase patterns at Waliguan that were slightly different from the global pattern. The mean CH₄ annual cycle at Waliguan shows an unusual pattern of two gentle peaks in summer and February along with two small valleys in early winter and spring and a mean peak-to-peak amplitude of 11 ppb, much smaller than amplitudes observed at most other mid- and high-northern latitude sites. The Waliguan CH₄ data are strongly influenced by continental Asian CH₄ emissions and provide key information for global atmospheric CH₄ models.     

外源碳氮添加对草地碳循环关键过程的影响

人类活动引起的大量的活性氮从大气沉降到生物圈.当前氮沉降对草地生态系统碳循环过程的影响机制仍然存在较大的不确定性.本文综述草地生态系统碳循环过程（植物光合作用、地上生物量、地下生物量、土壤呼吸、凋落物分解和土壤有机碳含量）对添加不同的氮源水平和不同施氮年限的响应,并分析这些过程变化的可能原因,同时,也阐述草地碳循环关键过程对外源碳输入的响应,并进一步分析了外源碳和氮输入对草地碳循环关键过程影响的微生物学作用机制.通过上述总结旨在强调说明碳源可利用性变化作为氮沉降背景下草地生态系统碳循环关键过程重要调控因素之一,开展相关研究对科学的管理我国草地资源配置和增加土壤碳汇方面理论的重要意义.     

采场调压数学模型在煤矿火区治理中的应用

采场调压可改变采场内气体流动的状况,抑制采空区自然发火。笔者采用Ｗａｒｄ 非线性运动方程,建立采场调压数学模型,利用有限元法对其进行求解。通过对小恒山煤矿东正巷出口的调压进行计算机模拟,从而掌握火区内部参数的变化趋势,及时预测调压潜力及效果,指导调压措施的进一步实施。     

林业REDD~+机制对中国低碳经济的启示——以环境与资源保护法为视角

森林固碳不仅成本低,并且还具有多种生态效益和巨大的经济、社会效益。发展碳汇林业,加强以林业为主的生态保护和建设,充分发挥森林生态系统作为生物措施对应对气候变化的作用显得尤为重要,也更具有长远和治本的意义。REDD+机制的提出,为广大发展中国家在共同但有区别的原则下参与全球气候变化活动带来了新的活力,也为中国的低碳经济带来了政策和法律的启示。但该机制对不同的国家有不同的内涵,国家责任不同,利益不同,代价亦不同,中国需持谨慎态度制定与之相关的政策法律。     

鱼类养殖对水体磷酸盐的影响：源、汇的半现场实验例证

设置4个温度水平（16℃,20℃,23℃和26℃）和3个投喂水平（1%,2%和饱食水平）,在类养殖场条件下饲喂许氏平鲉,研究其对水体磷酸盐浓度的影响.结果表明,在所有温度、投喂水平下,水体的磷酸盐浓度均有升、降.从物质平衡角度看,养殖鱼类是水体磷酸盐的源,但又不是单纯的源,因鱼粪和残饵等微粒的吸附作用,养殖鱼类有可能成为水体磷酸盐的汇。因此在评价鱼类养殖的环境容量时,慎用活性磷酸盐磷这个指标。此外,进行鱼类养殖环境影响评价时,应加强颗粒物的监测;为降低水体的磷负荷,磷酸盐和水体颗粒物质均应是生态调控的对象。