冰川生态系统固碳微生物研究进展

[目的] 海南海口含有丰富的温泉资源,对温泉微生物多样性进行研究,有助于进一步开发和利用海南温泉微生物资源。[方法] 本文采用Illumina HiSeq高通量测序技术对海口3个温泉[海甸岛荣域温泉（S1）、火山口开心农场温泉（S2）和西海岸海长流温泉（S3）] 水样中微生物ITS序列和16S rRNA基因V3-V4区进行测序及生物信息学分析,探究海口市3个不同区域的温泉真菌多样性与细菌多样性。[结果] （1）α多样性分析表明,真菌群落中,S3 > S1 > S2,而在细菌群落中,S2 > S1 > S3。β多样性分析表明,3个温泉真菌群落和细菌群落组成差异皆显著。（2）分类分析表明,温泉真菌群落优势菌门为子囊菌门（Ascomycota）和担子菌门（Basidiomycota）,细菌群落优势菌门为变形菌门（Proteobacteria）、拟杆菌门（Bacteroidetes）、Thermi、硝化螺旋菌门（Nitrospirae）、绿菌门（Chlorobi）、厚壁菌门（Firmicutes）、绿弯菌门（Chloroflexi）、放线菌门（Actinobacteria）。（3）CCA（Canonical correspondence analysis）分析表明,3个温泉的真菌群落主要影响因子是温度,细菌群落主要影响因子是总磷。[结论] 海南省海口市温泉中含有丰富的微生物资源,其微生物群落组成受多种环境因子影响,且影响真菌和细菌的主要环境因子不同。     

Affinity Laminated Chromatography Membrane Built‐in Electrodes for Suppressing Polysulfide Shuttling in Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries are promising candidates for energy storage, but suffer from capacity and cycling challenges caused by the serious shuttling effect of polysulfide (PS) ions. To address these issues, a sodium alginate (SA)‐derived affinity laminated chromatography membrane built‐in electrode is designed. This is the first attempt to utilize this type of membrane, which is widely used for the selective adsorption of proteins, in the battery field. An ordered multilayer structure throughout the electrode can easily be obtained, and the number of membrane layers can be also conveniently controlled by varying the cross‐linking time of SA. The PS shuttling effect is efficiently suppressed and the permeability of PSs is reduced by enveloping the carbon/sulfur powder in ultrathin laminated chromatography membranes. As a result, these designed electrodes deliver a superhigh initial capacity of 1492 mA h g^?1, with a capacity retention almost 20% higher than the contrast. This low‐cost and easily mass‐producible strategy inspired by affinity chromatography is expected to effectively solve the PS shuttling problem toward high‐loading and long‐lifetime Li–S batteries in practice.     

Direct Visualization of the Interfacial Degradation of Cathode Coatings in Solid State Batteries: A Combined Experimental and Computational Study

The interfacial instability between a thiophosphate solid electrolyte and oxide cathodes results in rapid capacity fade and has driven the need for cathode coatings. In this work, the stability, evolution, and performance of uncoated, Li₂ZrO₃‐coated, and Li₃B₁₁O₁₈‐coated LiNi_0.5Co_0.2Mn_0.3O₂ cathodes are compared using first‐principles computations and electron microscopy characterization. Li₃B₁₁O₁₈ is identified as a superior coating that exhibits excellent oxidation/chemical stability, leading to substantially improved performance over cells with Li₂ZrO₃‐coated or uncoated cathodes. The chemical and structural origin of the different performance is interpreted using different microscopy techniques which enable the direct observation of the phase decomposition of the Li₂ZrO₃ coating. It is observed that Li is already extracted from the Li₂ZrO₃ in the first charge, leading to the formation of ZrO₂ nanocrystallites with loss of protection of the cathode. After 50 cycles separated (Co, Ni)‐sulfides and Mn‐sulfides can be observed within the Li₂ZrO₃‐coated material. This work illustrates the severity of the interfacial reactions between a thiophosphate electrolyte and oxide cathode and shows the importance of using coating materials that are absolutely stable at high voltage.     

Energy–water and seasonal variations in climate underlie the spatial distribution patterns of gymnosperm species richness in China

Studying the pattern of species richness is crucial in understanding the diversity and distribution of organisms in the earth. Climate and human influences are the major driving factors that directly influence the large‐scale distributions of plant species, including gymnosperms. Understanding how gymnosperms respond to climate, topography, and human‐induced changes is useful in predicting the impacts of global change. Here, we attempt to evaluate how climatic and human‐induced processes could affect the spatial richness patterns of gymnosperms in China. Initially, we divided a map of the country into grid cells of 50 × 50 km² spatial resolution and plotted the geographical coordinate distribution occurrence of 236 native gymnosperm taxa. The gymnosperm taxa were separated into three response variables: (a) all species, (b) endemic species, and (c) nonendemic species, based on their distribution. The species richness patterns of these response variables to four predictor sets were also evaluated: (a) energy–water, (b) climatic seasonality, (c) habitat heterogeneity, and (d) human influences. We performed generalized linear models (GLMs) and variation partitioning analyses to determine the effect of predictors on spatial richness patterns. The results showed that the distribution pattern of species richness was highest in the southwestern mountainous area and Taiwan in China. We found a significant relationship between the predictor variable set and species richness pattern. Further, our findings provide evidence that climatic seasonality is the most important factor in explaining distinct fractions of variations in the species richness patterns of all studied response variables. Moreover, it was found that energy–water was the best predictor set to determine the richness pattern of all species and endemic species, while habitat heterogeneity has a better influence on nonendemic species. Therefore, we conclude that with the current climate fluctuations as a result of climate change and increasing human activities, gymnosperms might face a high risk of extinction.     

PSMD: An extensive database for pan‐species microsatellite investigation and marker development

Microsatellites are widely distributed throughout nearly all genomes which have been extensively exploited as powerful genetic markers for diverse applications due to their high polymorphisms. Their length variations are involved in gene regulation and implicated in numerous genetic diseases even in cancers. Although much effort has been devoted in microsatellite database construction, the existing microsatellite databases still had some drawbacks, such as limited number of species, unfriendly export format, missing marker development, lack of compound microsatellites and absence of gene annotation, which seriously restricted researchers to perform downstream analysis. In order to overcome the above limitations, we developed PSMD (Pan‐Species Microsatellite Database, http://big.cdu.edu.cn/psmd/ ) as a web‐based database to facilitate researchers to easily identify microsatellites, exploit reliable molecular markers and compare microsatellite distribution pattern on genome‐wide scale. In current release, PSMD comprises 678,106,741 perfect microsatellites and 43,848,943 compound microsatellites from 18,408 organisms, which covered almost all species with available genomic data. In addition to interactive browse interface, PSMD also offers a flexible filter function for users to quickly gain desired microsatellites from large data sets. PSMD allows users to export GFF3 formatted file and CSV formatted statistical file for downstream analysis. We also implemented an online tool for analysing occurrence of microsatellites with user‐defined parameters. Furthermore, Primer3 was embedded to help users to design high‐quality primers with customizable settings. To our knowledge, PSMD is the most extensive resource which is likely to be adopted by scientists engaged in biological, medical, environmental and agricultural research.     

Substrate availability regulates the suppressive effects of Canada goldenrod invasion on soil respiration

基质有效性调节加拿大一枝黄花入侵对土壤呼吸的抑制作用 外来植物入侵不仅会降低河边近岸湿地生态系统植被多样性,而且会改变湿地生态系统的地下碳过程。外来入侵植物加拿大一枝黄花(Solidago canadensis L.)已广泛入侵我国东南部地区,但加拿大一枝黄花入侵对入侵地生态系统地下土壤碳循环过程的影响却知之甚少。本研究通过野外原位观测实验和温室模拟入侵实验,探究外来植物加拿大一枝黄花入侵对入侵地土壤呼吸的影响规律及其驱动因素。野 外原位观测实验开展于2018年7月21日至12月15日,期间每周测定样地土壤呼吸。温室模拟入侵实验开展于2019年7月15日至12月15日,期间每月1日与15日上午测定土壤呼吸、自养呼吸和异养呼吸。土壤呼吸、自养呼吸和异养呼吸通过静态箱结合深埋根系隔离法测定。野外原位观测实验和温室模拟入侵实验结果均显示,加拿大一枝黄花的入侵降低了土壤二氧化碳的排放通量。加拿大一枝黄花入侵对土壤呼吸的抑制作用可能归因于其入侵引起的土壤可利用底物质量与数量的变化,表明外来入侵植物加拿大一枝黄花可通过改变植物释放基质以及与本地植物和/或土壤微生物争夺土壤有效基质而影响土壤碳循环。这些研究结果对于评估外来入侵植物对入侵地地下碳动态的影响以及对全球变暖的贡献具有重要意义。     

Seasonal and interannual variations of ecosystem photosynthetic characteristics in a semi-arid grassland of Northern China

北方半干旱草原生态系统光合参数的季节和年际变异 生态系统表观量子效率(α)、最大光合速率(P_max)和暗呼吸速率(R_d)不仅反映了生态系统水平 光合生理特征,同时也是碳循环模型中光合过程模拟的关键参数。气候和植被因子都会影 响光合参数的季节和年际变异,但二者在光合参数调控过程中的相对贡献和作用途径尚不清晰。本研究基于连续12年(2006–2017)的涡度相关观测数据,分析了内蒙古半干旱典型草原光合参数的季节和年际变化规律;利用回归分析和结构方程模型(SEM)方法明晰了环境和生理调控的作用途径及相对贡献。结果发现,光合参数(α、P_max和R_d)均表现出单峰的季节变化趋势,并呈现明显的年际波动。温度(T_a)和土壤含水量(SWC)的变化共同影响光合参数的季节变化,而SWC主导了其年际变异。α和R_d的变化主要由T_a决定,而Pmax的变化主要受SWC的影响。SEM模型分析表明,除了直接作用外,环境因子主要通过影响冠层水平气孔导度(gc)对光合参数和碳同化生理过程进行调控。此外,叶面积指数对光合参数特别是Pmax的季节和年际变异起主要调控作用。以上结果明确了环境和植被共同决定了生态系统水平光合参数的季节和年际变异,并强调了在水分受限的草原生态系统中,植被生理调控在光合碳同化能力和碳汇功能评估中的重要作用。     

Development and characterization of 33 polymorphic microsatellite markers in Trachurus japonicus by SLAF-seq technology

Trachurus japonicus is an economically important fish in the northwestern Pacific Ocean. However, its resources have declined seriously and there is an urgent need for a wide-range of investigations of the existing genetic resources. This requires a large number of diverse molecular markers with high discriminating power. In this study, we identified 43,264 perfect SSRs in T. japonicus genome using SLAF-seq technology. Of these, we randomly selected 106 SSRs (tri-nucleotide to hexa-nucleotide) to test for polymorphism. Eventually, we successfully developed a total of 33 loci including 8 tri-nucleotide and 25 long repeat motifs (tetra-nucleotide to hexa-nucleotide). The number of alleles (Na) of these loci ranged from 4 to 24 (mean 12.6). The observed heterozygosity (Ho) and expected heterozygosity (He) varied from 0.258 to 0.969 (mean 0.723) and from 0.452 to 0.962 (mean 0.827), respectively. All loci except TJ6-7 were highly informative (PIC > 0.5). These results showed that the shortlisted 33 loci exhibited moderate to relatively high genetic diversity, of which 18 were regarded as highly polymorphic and well-resolved. In summary, these diverse and potential microsatellites detected in our study provide substantial genetic basis for the screening of polymorphic SSR markers of T. japonicus and also provide a powerful tool to perform further studies on the genetic resource assessment and conservation of T. japonicus.