土地退化过程、机制与影响——以土地退化与恢复专题评估报告为基础

土地退化已成为威胁32亿人口福祉的全球性重大环境问题之一,近年来受到UN、IPBES、IPCC等组织的广泛关注。然而,当前的土地退化研究中,还存在概念不清、过程和机理不明、影响认识不彻底等问题,因此,厘清土地退化的概念、过程和机制是防止土地退化和恢复退化土地的关键。以生物多样性和生态系统服务政府间科学-政策平台（IPBES）土地退化与恢复专题评估报告为基础,剖析了土地退化的概念、过程、机制及影响：土地退化过程受自然环境和人类活动两大因素驱动,退化过程包括疑似退化、历史退化、敏感退化、弹性退化、持续退化和永久退化6种状态;土地退化类型可根据土地利用类型分为城市土地退化、农田退化、森林与草地退化、湿地退化等;土地退化具有多重影响,包括威胁食物和水安全,影响生物多样性及生态系统服务,引发地区冲突、大规模人口迁徙和疾病传播,加剧贫困及全球气候变化。土地退化过程、机制及影响的审视将为我国沙漠化、石漠化等土地退化的进一步研究提供理论指导,并为我国"山水林田湖草"土地系统的统筹治理和"美丽中国"、"生态文明"建设提供决策支持。     

气候变化影响下海岸带脆弱性评估研究进展

近百年来,全球气候系统正经历着以全球变暖为主要特征的显著变化。研究海岸带系统对气候变化的响应机制,评估气候变化对海岸带社会、经济和生态的潜在影响,提出切实可行的应对策略,是保障海岸带系统安全的重要前提。回顾了IPCC的四次评估报告,分析了全球气候变化对海岸带的影响。总结了海岸带脆弱性评估框架以及脆弱性评价指标体系,综述了国内外气候变化影响下海岸带脆弱性评估研究的进展。在综述国内外该领域研究进展的基础上,展望了气候变化影响下海岸带脆弱性评估研究。全球气候变化及其对海岸带的影响还有大量的科学技术问题需要进一步探讨,同时也需要对各种适应气候变化措施的可行性和有效性进行研究和验证。     

IPBES土地退化和恢复专题评估报告及其潜在影响

随着国际社会对生物多样性保护和人类福祉关注度的提升, 土地退化作为全球面临的重要问题逐渐成为国际公约和进程关注的热点问题。生物多样性和生态系统服务政府间科学政策平台(Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, IPBES)将“土地退化和恢复”列入2014-2018年工作方案, 开展评估。2018年3月, 该评估报告在IPBES第六次全体会议上获得通过。本文概述了评估报告的主要内容和结论, 探讨了对其他国际进程的可能影响。评估报告在IPBES概念框架的基础上, 厘清了土地退化的概念与内涵, 全面梳理了土地退化对人类生活质量的影响, 阐明了土地退化的现状和进程, 分析了直接和间接驱动因素与土地退化的作用, 揭示了土地退化与人类福祉的关系, 提出了土地退化和恢复的对策建议。该项评估将为各国决策者制定政策工具提供最有效的技术支撑, 为相关国际进程谈判提供重要的科学参考。中国作为生物多样性大国, 应重视IPBES的评估机制并积极参与, 加强促进生物多样性和生态系统服务领域的科学成果转化, 适时针对国内关键问题启动相关评估, 促进我国生态文明建设和山水林田湖草系统治理, 实现美丽中国的建设目标。     

气候变暖了，雪域高原的未来在哪里？

由人类活动增强引起的气候变化已成为深刻影响21世纪全球可持续发展的一个重大问题。政府间气候变化专门委员会（IPCC）第三次评估报告明确指出，1860-2000年全球平均气温上升了0．4～0．8摄氏度。北半球雪盖和海冰范围已经明显缩小、极端事件（例如高温天气、强降水、热带气旋强风等）时有发生，一些地区越来越干旱。     

湿地退化研究进展

受经济发展、城市扩张、气候变化的影响,湿地退化已经成为全球性现象,是当前国际湿地科学前沿领域的热点。从湿地退化标准、退化特征、退化分级、退化过程、退化机理、退化监测体系、退化评价指标与指标体系、退化监测新技术及其生态恢复理论与技术9个方面系统地介绍了当前湿地退化研究进展。结果表明湿地退化过程、退化机理、退化评价指标体系和退化湿地监测、恢复与重建研究是当前研究的重点,在未来相当长的时间内,全球气候变化、湿地退化的微观过程与机理、湿地生态系统的可持续利用将会是重要的研究方向。最后就我国当前湿地退化研究存在的问题进行了分析,并提出近期湿地退化研究亟待开展的11项研究工作,供我国湿地退化研究工作者参考。     

ISAAA信息

可持续农业发展全球委员会的建议一个由农业、气候、食品与营养、经济以及自然资源高级专家联合组成的独立的有关"农业与气候变化可持续发展全球委员会"近日发布了一份有关粮食安全政策建议的报告。该委员会得到了国际农业研究磋商小组(CGIAR)气候变化、农业与粮食安全研究项目     

ISAAA信息

新任FAO总干事表示重新重视粮食安全联合国粮农组织(FAO)第八任总干事JoséGraziano da Silva于近期上任,并表示重新推进粮食安全。他指出,消除饥饿和其他的全球挑战不应分开来看,比如复兴国家经济、保护自然资源、减轻并适应气候变化。FAO将致力于以下几方面的工作:消除饥饿,可持续粮食生产和消费,更为公平的全球粮食     

跨国土地利用及其生态影响

在全球食物价格不断上涨,粮食安全已经威胁到经济安全的环境下,跨国农用地投资成为国际浪潮。跨国农用地投资推动着各国的土地资源向全球化资源转变,对土地的跨国利用成为全球土地资源优化配置的必然。在对跨国土地利用的背景及现状进行阐述的基础上,指出"代理性农业耕作"方式对区域生态环境可能造成的影响。同时,新型农业科技与跨国土地利用的结合,也在推动着农业经济发展的同时,改变着传统的土地利用模式,进而改变着区域生态环境。最后,指出需要对跨国土地利用做出理性分析并建立相关的国际规则,从而维护可持续粮食安全及生态安全。     

全球气候变暖对中国鸟类区系的影响

近百年来,气候系统变暖是毋庸置疑的.政府间气候变化专门委员会(IPCC)的第4次评估报告中指出,最近100年中(1906～2005年)气温上升了约0.74℃.已经有充分的研究表明全球气候变暖对鸟类分布,种群动态以及物候等方面产生了影响.根据作者以往研究经历以及对近20年来中国鸟类分布变化的资料进行统计分析,已知受气候变暖而改变分布范围的鸟类共120种,其中东洋界鸟类88种,古北界鸟类12种,广布种鸟类20种.因受全球气候变暖影响,中国鸟类区系的变化速率加快.本文初步探讨气候变化对我国鸟类产生的影响,并对今后该领域的研究提出一些建议.     

北京市居民食物消费碳足迹

碳足迹作为一种评价碳排放影响的全新测度方法,已被用来衡量人类活动对大气环境和气候变化的影响。食物是人类的首要消费品,其消费的碳足迹反应维持一个区域人口的基本食物需求的碳排放以及对气候变化的影响。在碳足迹理论和模型的基础上,根据北京市食物的供应和消费现状情况,利用生命周期法(Life cycle analysis LCA),计算和分析了北京市居民食物消费的碳足迹。得到北京市居民食消费碳足迹为476.8×104t,约占北京市总碳足迹的6%,人均碳足迹为310.0kgCO2/人,占北京市家庭消费碳排放的23.3%,只占北京市能源消费人均碳排放量的5.96%,反映了居民食物消费对全球气候变化造成的影响有限。食物消费碳足迹最大的为粮食,其次为瓜果蔬菜豆类,总共占到65%以上,而在食物生命周期过程中,食物的再加工炊事过程碳排放最大,超过50%,合理减少食物加工炊事过程中碳排放将是减少食物消费碳排放的重要途径之一。其次为化肥农药施用,占到23.23%,减少食物生产过程中化肥农药使用,提高化肥农药的使用效率,或者进行生态农业尽量不使用化肥农药,北京市每年可减少135.1×104t CO2排放,人均87.84kgCO2/人,是有效的减排途径之一。     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.