Robustness of the biotic indicators used for classification of ecological status of lotic water bodies: A testing method when the data series are short

Successful implementation of the Water Framework Directive and achieving its objective of good ecological status of all water bodies depend on the power of the set of monitoring indicators to capture the change in the ecological status of aquatic systems. In this context, testing the robustness and sensitivity of ecological indicators currently used for assessing the status of lotic water bodies is instrumental for the adaptation and further development of assessment methods. This is also a prerequisite for an effective, context-based monitoring system and for improving the quality of the decision making for water bodies. This is particularly challenging in regions where the sets of indicators are under development, the data series are relatively short and data which addresses the individual error sources are lacking. Here we show that hierarchical clusters and ordination analysis provide appropriate tools with which the validity of the ecological status of water bodies set up based on biological multimetric monitoring indices in a small water basin could be tested. We hypothesize that robust and informative monitoring methods classify all water bodies belonging to a single ordination grouping in the same quality class (high, good, moderate, poor or bad). In our case study multimetric biological indicators failed to discriminate between the good and moderate ecological status. Community structure as well as water conductivity and nitrate load were primarily responsible for the observed difference between ordination groupings. Inconsistencies shown in our case study are likely to be induced by insufficient refinement of monitoring schemes and by the constraints existing in the data series and available metadata. We show that multiplication of indicators leads to discrepant interpretation and problematic application. Proposed ordination analysis proves to be a simple and useful tool to detect such discrepancies and support further progress in indicator development. Integrated and longer data and metadata series are needed to refine context-based monitoring methods.     

Comparative analysis of leaf angle and sclerophylly of Aspidosperma quebracho‐blanco on a water deficit gradient

Abstract Aspidosperma quebracho‐blanco is found throughout the Chaco (17°?33°S) in Argentina, and it is the dominant tree species in the arid Chaco. Under the hypothesis that morpho‐physiological features of A. quebracho‐blanco change as a function of its geographical position on a water deficit gradient, it was predicted that with increasing water stress, leaf angles (specifically horizontal) would be greater and mean values of the leaf mass per area would increase. These leaf characteristics were compared at three points on a water deficit gradient extending from the humid Chaco through semi‐arid Chaco to the arid Chaco of Argentina (south‐west to north‐east rainfall gradient, from 350 to 1200 mm annual mean precipitation). Twig and leaf positions were modified and water potentials were measured at the highest heating hour of the day at a site of the arid Chaco. Daily and seasonal water potential variations of untreated twigs were also observed. Leaf angle modification towards horizontal produced more negative twig water potentials with respect to those of leaves in non‐horizontal positions. The comparison of the three sites along the gradient showed contrasting patterns of leaf‐angle frequency distribution of adults. In Chancaní (mean annual temperature: 18–24°C, mean annual precipitation: 450 mm, arid) there was a higher frequency of angles near 90° for non‐pendulous and about 270° for pendulous trees. Leaf angles in Copo (semi‐arid) and Chaco National Park (mean annual temperature: 20–23°C, mean annual precipitation: 1300 mm humid) were widely distributed with higher frequency towards the angles near 0° and 180°. This sclerophyllous tree species showed plasticity in its leaf traits along the precipitation gradient. Plasticity in leaf mass per area and leaf position enables plants to develop efficiently in contrasting environmental conditions of humidity and aridity.     

Beneficial effects of activated charcoal on bulblet production in tissue cultures of Muscari armeniacum

Production of bulblets of Muscari armeniacum through tissue culture is enhanced when 1 g/l activated charcoal is added to a modified Murashige and Skoog (MS) medium. Bulblet regeneration is direct from bulb scale explants with no intermediate callus growth. Bulblets can be transferred successfully to a greenhouse environment directly from aseptic culture.     

不同时间尺度喀斯特小流域溪流水文水化学特征

通过野外定位监测和室内测试分析,研究了典型喀斯特峰丛洼地小流域2013年6月—2014年3月期间溪流不同时间尺度(昼夜、次降雨、季节)主要水文水化学指标的动态变化特征及其影响因素.结果表明: 日尺度无雨条件下,溪流水化学过程表现出明显的波动规律,植物光合作用和呼吸作用在昼夜间的相互转换是导致这种变化的主要原因;次降雨尺度下,溪流水文水化学过程的日尺度效应被掩盖,水文水化学过程主要受控于前期无雨天数和降雨强度;从季节尺度看,溪流对降雨表现出较快的响应,雨季响应快于旱季,降雨季节分配差异和温度是影响溪流水文水化学变化的主要因素.     

Analysis of the community structure of abyssal kinetoplastids revealed similar communities at larger spatial scales

Knowledge of the spatial scales of diversity is necessary to evaluate the mechanisms driving biodiversity and biogeography in the vast but poorly understood deep sea. The community structure of kinetoplastids, an important group of microbial eukaryotes belonging to the Euglenozoa, from all abyssal plains of the South Atlantic and two areas of the eastern Mediterranean was studied using partial small subunit ribosomal DNA gene clone libraries. A total of 1364 clones from 10 different regions were retrieved. The analysis revealed statistically not distinguishable communities from both the South-East Atlantic (Angola and Guinea Basin) and the South-West Atlantic (Angola and Brazil Basin) at spatial scales of 1000–3000 km, whereas all other communities were significantly differentiated from one another. It seems likely that multiple processes operate at the same time to shape communities of deep-sea kinetoplastids. Nevertheless, constant and homogenous environmental conditions over large spatial scales at abyssal depths, together with high dispersal capabilities of microbial eukaryotes, maintain best the results of statistically indistinguishable communities at larger spatial scales.     

Metabolic engineering of Clostridium acetobutylicum for the enhanced production of isopropanol‐butanol‐ethanol fuel mixture

Butanol is considered as a superior biofuel, which is conventionally produced by clostridial acetone‐butanol‐ethanol (ABE) fermentation. Among ABE, only butanol and ethanol can be used as fuel alternatives. Coproduction of acetone thus causes lower yield of fuel alcohols. Thus, this study aimed at developing an improved Clostridium acetobutylicum strain possessing enhanced fuel alcohol production capability. For this, we previously developed a hyper ABE producing BKM19 strain was further engineered to convert acetone into isopropanol. The BKM19 strain was transformed with the plasmid pIPA100 containing the sadh (primary/secondary alcohol dehydrogenase) and hydG (putative electron transfer protein) genes from the Clostridium beijerinckii NRRL B593 cloned under the control of the thiolase promoter. The resulting BKM19 (pIPA100) strain produced 27.9 g/l isopropanol‐butanol‐ethanol (IBE) as a fuel alcohols with negligible amount of acetone (0.4 g/l) from 97.8 g/l glucose in lab‐scale (2 l) batch fermentation. Thus, this metabolically engineered strain was able to produce 99% of total solvent produced as fuel alcohols. The scalability and stability of BKM19 (pIPA100) were evaluated at 200 l pilot‐scale fermentation, which showed that the fuel alcohol yield could be improved to 0.37 g/g as compared to 0.29 g/g obtained at lab‐scale fermentation, while attaining a similar titer. To the best of our knowledge, this is the highest titer of IBE achieved and the first report on the large scale fermentation of C. acetobutylicum for IBE production. © 2013 American Institute of Chemical Engineers Biotechnol. Prog., 29:1083–1088, 2013     

全球变化下的国际水文学研究进展:特点与启示——2011年欧洲地球科学联合会会员大会述评

欧洲地球科学联合会2011年会员大会于4月3-8日在奥地利首都维也纳举行。其中,水文学专场重点讨论了全球变化对陆地表层水文过程的影响。主要包括气候变化下的洪涝灾害与干旱胁迫、冰川融雪、降雨特性、区域水平衡、土壤侵蚀与泥沙搬运、景观进化与水文过程、地下水与溶质迁移、植被动态与水文格局、气候-水-健康、气候和土地利用综合影响下的区域水行为、耦合水与人类经济社会的关键要素、基于公众和利益相关者参与的水资源优化管理等重要科学进展。众多议题凸现了多学科交叉、多区域、跨尺度、系统性以及先进技术设备的广泛应用等几大特点,对于今后应对气候变化和环境变迁所带来的种种挑战具有重要启示。当前和今后的工作中应瞄准与把握以下几个基本原则。(1)进一步加强基础研究、促进学科交融与渗透,以实现方法和理念互补、共同解决复杂生态学问题。(2)重视区域分异、以凸现具体科学问题,实现研究目标、对象、内容和方法的有机统一。(3)重视系统性研究,加强国际合作、共同研发,促进先进技术和研究手段的创新与应用。     

Chromosome‐level reference genome of X12, a highly virulent race of the soybean cyst nematode Heterodera glycines

Soybean cyst nematode (SCN, Heterodera glycines) is a major pest of soybean that is spreading across major soybean production regions worldwide. Increased SCN virulence has recently been observed in both the United States and China. However, no study has reported a genome assembly for H. glycines at the chromosome scale. Herein, the first chromosome‐level reference genome of X12, an unusual SCN race with high infection ability, is presented. Using whole‐genome shotgun (WGS) sequencing, Pacific Biosciences (PacBio) sequencing, Illumina paired‐end sequencing, 10X Genomics linked reads and high‐throughput chromatin conformation capture (Hi‐C) genome scaffolding techniques, a 141.01‐megabase (Mb) assembled genome was obtained with scaffold and contig N50 sizes of 16.27 Mb and 330.54 kilobases (kb), respectively. The assembly showed high integrity and quality, with over 90% of Illumina reads mapped to the genome. The assembly quality was evaluated using Core Eukaryotic Genes Mapping Approach and Benchmarking Universal Single‐Copy Orthologs. A total of 11,882 genes were predicted using de novo, homolog and RNAseq data generated from eggs, second‐stage juveniles (J2), third‐stage juveniles (J3) and fourth‐stage juveniles (J4) of X12, and 79.0% of homologous sequences were annotated in the genome. These high‐quality X12 genome data will provide valuable resources for research in a broad range of areas, including fundamental nematode biology, SCN–plant interactions and co‐evolution, and also contribute to the development of technology for overall SCN management.     

圈养马麝的个性分类

本研究在甘肃兴隆山国家级自然保护区马麝繁育场展开,分别于2012年7月和2013年8月,针对374只圈养马麝,采用基于量表的个性评价法进行评价调查。结果表明:可建立包含17个个性项目的圈养马麝个性量表,因子分析显示每个项目公因子方差和载荷均大于0. 4,各因子累计贡献率为60. 33%,表明此量表具有较好的结构效度。此外Cronbach’sα系数为0. 787,表明量表具有较高的内部一致性信度,量表设计合理;因子分析和聚类分析结果显示,可将圈养马麝划分为五大个性维度:侵略性、社会性、刻板性、温顺性、活跃性。研究发现,圈养马麝个性维度与野生个体的个性类型划分存在差异,主要是受圈养条件和人为干扰等影响。圈养马麝个性量表和五大个性维度的建立对指导马麝繁育管理具有重要实践价值,填补了马麝个性研究的空缺,并为进一步进行麝类动物个性研究奠定了基础。另外,此类个性层次研究方法具有较好区分度,可为其他动物个性的初期研究提供参考。     

Membrane‐Free Zn/MnO2 Flow Battery for Large‐Scale Energy Storage

The traditional Zn/MnO₂ battery has attracted great interest due to its low cost, high safety, high output voltage, and environmental friendliness. However, it remains a big challenge to achieve long‐term stability, mainly owing to the poor reversibility of the cathode reaction. Different from previous studies where the cathode redox reaction of MnO₂/MnOOH is in solid state with limited reversibility, here a new aqueous rechargeable Zn/MnO₂ flow battery is constructed with dissolution–precipitation reactions in both cathodes (Mn²⁺/MnO₂) and anodes (Zn²⁺/Zn), which allow mixing of anolyte and catholyte into only one electrolyte and remove the requirement for an ion selective membrane for cost reduction. Impressively, this new battery exhibits a high discharge voltage of ≈1.78 V, good rate capability (10C discharge), and excellent cycling stability (1000 cycles without decay) at the areal capacity ranging from 0.5 to 2 mAh cm^‐2. More importantly, this battery can be readily enlarged to a bench scale flow cell of 1.2 Ah with good capacity retention of 89.7% at the 500th cycle, displaying great potential for large‐scale energy storage.