Composition and origin of lipid biomarkers in the surface sediments from the southern Challenger Deep, Mariana Trench

The surface sediments collected from the southern Mariana Trench at water depths between ca.4900 m and 7068 m were studied using lipid biomarker analyses to reveal the origin and distribution of organic matters. For all samples, an unresolved complex mixture(UCM) was present in the hydrocarbon fractions, wherein resistant component tricyclic terpanes were detected but C_(27)-C _(29) regular steranes and hopanes indicative of a higher molecular weight range of petroleum were almost absent.This biomarker distribution patterns suggested that the UCM and tricyclic terpanes may be introduced by contamination of diesel fuels or shipping activities and oil seepage elsewhere. The well-developed faults and strike-slip faults in the Mariana subduction zone may serve as passages for the petroleum hydrocarbons. In addition, the relative high contents of even n-alkanes and low Carbon Preference Indices indicated that the n-alkanes were mainly derived from bacteria or algae. For GDGTs, the predominance of GDGT-0 and crenarchaeol, together with low GDGT-0/Crenarchaeol ratios(ranging from0.86 to 1.64), suggests that the GDGTs in samples from the southern Mariana Trench were mainly derived from planktic Thaumarchaeota. However, the high GDGT-0/crenarchaeol ratio(10.5) in sample BC07 suggests that the GDGTs probably were introduced by methanogens in a more anoxic environment. Furthermore, the n-alkanes C_(19)-C_(22) and the n-fatty acids C_(20:0)-C_(22:0) were depleted in^(13)C by 3‰ compared to n-alkanes C_(16)-C_(18) and the n-fatty acids C_(14:0)-C_(18:0), respectively, which was interpreted to result from the preferential reaction of fatty acid fragments with carbon "lighter" terminal carboxyl groups during carbon chain elongation from the precursors to products. The abundance of total alkanes, carboxylic acids, alcohols and total lipids were generally increased along the down-going seaward plate, suggesting the lateral organic matter inputs play an important role in organic matter accumulation in hadal trenches. The extremely high contents of biomarkers in sample BC11 were most likely related to trench topography and current dynamics, since the lower steepness caused by graben texture and proximity to the trench axis may result in higher sedimentation rate. This paper, for the first time, showed the biomarker patterns in surface sediments of the Mariana Trench and shed light on biogeochemistry of the hardly reached trench environment.

Microbial diversity in the sediments of the southern Mariana Trench

Microbial diversity in the abyssal sediments beneath the seafloor of 30,94,and 151cm near the southern end of the Mariana Trench was analyzed in the Illumina HiSeq 2500 platform.Results show that the microbial populations were dominated by bacteria but merely no archaea were identifi ed at the three depths.In the bacterial community,Proteobacteria and Firmicutes dominated the total taxon tags,followed by Bacteroidetes,Actinobacteria,Planctomycetes,Cyanobacteria,and Chloroflexi,which together account for over 99%of the total population.Similar to that in the seawater in the trench,the operational taxonomic units(OTUs)belonging to Gammaproteobacteria from the sediment samples showed high abundance.However,common bacterial OTUs in the water of the trench including Nitrospirae and Marinimicrobia were hardly found in the sediments from the southern Mariana Trench or the hadal region.Therefore,this study documented for the first time the compositions of microbial diversity in the trench sediments,revealed the difference in microbial diversity in water and sediment of the trench and will enrich the knowledge on the microbial diversity in the abyssal areas.

Target Deployment and Retrieval Using JIAOLONG Manned Submersible in the Depth of 6600 m in Mariana Trench

China＇s 7000 m manned submersible JIAOLONG carried out an exploration cruise at the Mariana Trench from June to July 2016. The submersible completed nine manned dives on the north and south area of the Mariana Trench from the depth of 5500 to 6700 m, to investigate the geological, biological and chemical characteristics in the hadal area. During the cruise, JIAOLONG deployed a gas-tight serial sampler to collect the water near the sea bottom regularly. Five days later, the sub located the sampler in another dive and retrieved it successfully from the same location, which is the first time that scientists and engineers finished the high accuracy in-situ deployment and retrieval using a manned submersible with Ultra-Short Base Line （USBL） positioning system at the depth more than 6600 m. In this task, we used not only the USBL system of the manned submersible but also a compound strategy, including five position marks, the sea floor terrain, the depth contour, and the heading of the sub. This paper introduces the compound strategy of the target deployment and retrieval with the practical diving experience of JIAOLONG, and provides a promising technique for other underwater vehicles such as manned submersible or Remote Operated Vehicle （ROV） under similar conditions.

The Relative Importance of Nitrogen vs. Moisture Stress May Drive Intraspecific Variations in the SLA-RGR Relationship: The Case of <i>Picea mariana</i>Seedlings

Plants acclimate to nitrogen (N) or moisture stress by respectively increasing photosynthetic N use efficiency (PNUE) or water use efficiency (WUE), in order to maximize their relative growth rate (RGR). These two phenotypic adaptations have opposite effects on specific leaf area (SLA). Thus, intraspecific variations in the SLA-RGR relationship should reflect the relative importance of N vs. moisture stress in plants. In this study, we measured needle gas exchanges and N concentrations in order to derive PNUE and WUE, as well as SLA and RGR of black spruce (Picea mariana) seedlings growing on a rapidly drained site in the presence or absence of Kalmia angustifolia. The eradication of Kalmia had resulted in a ~140% increase in seedling growth over a 6 year period. We found a negative SLA-RGR relationship where Kalmia had been eradicated, and a positive one where Kalmia had been maintained. Kalmia eradication resulted in higher WUE when measurements were made directly on the seedlings, and in lower PNUE when twigs were rehydrated prior to gas exchange measurements. Our data suggest that the bigger seedlings on Kalmia-eradicated plots increase RGR by decreasing SLA, as a means of coping with moisture stress. By contrast, increasing SLA on noneradicated plots may be a means of coping with nutrient stress exerted by Kalmia. The SLA-RGR relationship could potentially be used to identify the limiting resource for black spruce seedlings in different environments.

Structural Elucidation of Condensed Tannin from <i>Picea mariana</i>Bark

The aim of this work was to determine the structural characteristics of the condensed tannins isolated from the aqueous extract of black spruce (Picea mariana Mill) bark. This is the first report on the structural characterization of condensed tannins from black spruce bark. The condensed tannins from the hot water extract prepared from Picea mariana bark were isolated by column chromatography on Sephadex LH-20 media. In this study, UV-visible and 13C-NMR spectroscopic techniques, along with pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and liquid chromatogramphy analyses were applied to determine the structural characteristics of black spruce bark tannins. We have confirmed for the first time the presence of methoxylated B-rings in the flavanol units of condensed tannins from black spruce bark, which could be regarded as further contribution to the chemotaxonomy of the genus Picea. The methoxylation of Norway spruce bark condensed tannins have been demonstrated previously.

A preliminary study on microtextures，structures and mineralizing processes of hydrothermal chimneys in Mariana Trough

Microtextures and struetures of 9 hydrothermal chimneys sampled on the small spreading ridge Of the Mari ana Trough during SONNE Cruise 57 (SO57) and 69 (SO69) in 1988 and 1990 were studied by means of scanning electron microscope. The results reveal that the two types of chimneys from the Mariana Trough. the 'silicic chimneys' containing Fe sulfide and the pure 'silica chimneys' without sulfide, vary distinctly not only in mineral and chemical compositions, but also in microtextures and structures. The silicic chimneys generally show three major types of microtextures.The inside of the chimneys is dominated by holocrystalline or semicrystalline idiomorphic and hypidiomorphic granular textures and the outwall by amorphous colloidal texture. In some of the silicic chimneys relict texture is observed. However,the pure silica chimneys show chiefly amorphous colloidal texture from the inside to the outwall. Microstructurally. theinside of the silicic chimneys is dominated by a 'silica-covering' structure and a 'voidfilling' structure, and the outwall by a chain-like or three-dimentional chain-network structure built up by individual opal globules, whereas the pure silica chimneys are mainly three-dimentional chain-network and the dense silica bands in structure. These variations suggest that not only mineralizing conditions but also processes differ distinctly during the formation of the two types of chimneys, and that hydrothermal mineralization in the Mariana Trough shows a multistage or multieplsodical nature.

Genetic Variation in Picea mariana ×P. rubens Hybrid Populations Assessed with ISSR and RAPD Markers

Interspecific hybridization can result in significant shifts in allele frequencies. The objective of the present study was to assess the level of genetic variation in populations of P. mariana × P. rubens hybrids derived from artificial crosses. Progenies from backcross populations created through a series of controlled pollinations among P. mariana and P. rubens trees across the hybridization index were analyzed. Several Inter Simple Sequence Repeat (ISSR) and Random Amplified Polymorphic DNA (RAPD) primers were used to amplify genomic DNA samples from each population. ISSR primers produced from 30% to 52% polymorphic loci. The level of polymorphism was higher with RAPD markers, ranging from 57% to 76%. Overall, the two marker systems generated similar levels of polymorphic loci for P. mariana and P. rubens populations. No significant differences were found among the P. mariana × P. rubens populations analyzed and between the hybrids and the parental populations regardless of the molecular marker used. This confirms the genetic closeness of P. mariana and P. rubens species.

马里亚纳海沟挑战者深渊南坡JL7KBC03短柱样硅质软泥沉积的物源、沉积环境和碳储库效应

海斗深渊是影响地球系统演化的关键一环,但由于超深水深导致的样品匮乏,对其沉积过程的精细研究仅见零星报道。本研究基于马里亚纳海沟挑战者深渊南坡JL7KBC03插管柱样系统的微体古生物、沉积学、矿物学研究,对该区沉积档案的物源、沉积环境记录进行解读。结果显示:(1)沉积物以第四纪硅藻软泥为主,其中大筛盘藻(Ethmodiscus rex)含量达99%以上。大筛盘藻的激发,可能为晚更新世冰期时段南极中层水入侵西北太平洋期间,南极“硅溢漏”效应对低纬水体溶解硅的补充,以及冰期风尘铁元素的激发所致。(2)沉积柱样中夹杂的数层暗色薄层,指示了研究区频繁的火山、热液活动。沉积物矿物、元素地球化学物源分析结果表明:研究区非生物组分物质与九州-帕劳海脊和马里亚纳海槽物质相近,陆源风尘和太平洋热液物质的贡献则相对较小。(3)海斗深渊独特的地形特征与水动力条件,利于有机质的快速沉降与埋藏,以硅藻软泥等形式将大量有机碳封存在深渊底部,动态调节着海洋碳储库与岩石圈碳储库之间的相互转化,是研究全球碳循环和碳封存的重要组成部分。

马里亚纳海沟“挑战者”深渊沉积物地球化学特征及成因机制

【目的】为探究马里亚纳海沟“挑战者”深渊沉积物的主要类型、地球化学特征和成因机制。【方法】以马里亚纳海沟“挑战者”深渊从北坡(上覆板块)、轴部到南坡(俯冲板块)16个站位的沉积物和蚀变基岩开展矿物学及地球化学分析。【结果与结论】“挑战者”深渊沉积物分为褐红色深海黏土质沉积物、硅质生物软泥、自生沉积物(富锰微结核)和钙质生物软泥四种主要类型。其中,褐红色深海黏土质沉积物为深渊沉积物的主要类型,对深渊沉积物的成分贡献最大,其主量、微量元素地球化学特征与洋壳蚀变基岩具有相似性。提出了褐红色深海黏土质沉积物成因主要源于俯冲板块和上覆板块玄武质基岩蚀变的观点。此外,深渊底部活跃的有机质早期成岩作用,对沉积物地球化学性质产生了重要影响,是导致“挑战者”深渊沉积物相比邻近深海沉积物具有较低稀土元素含量和富集微锰结核的主要原因。

基于残差神经网络的马里亚纳海沟地形反演

为提高利用重力异常数据反演马里亚纳海沟地形的精度,基于残差深度神经网络(residual deep neural network,RDNN)方法和重力异常等数据反演了马里亚纳海沟的1′×1′海底地形,通过实测检核点水深对RDNN模型的精度进行评估,并和重力地质法(gravity-geology method,GGM)模型结果进行对比。结果表明RDNN较GGM对马里亚纳海沟地形反演更为精细,实测水深检核表明RDNN模型均方根误差为128.98 m,优于GGM模型的150.14 m,且RDNN与船测检核水深也有更好一致性,RDNN深度学习模型为利用重力异常数据反演高精度海底地形提供了参考和依据。

马里亚纳海沟柱状沉积物稀土地球化学特征及其指示意义

对我国载人潜器＂蛟龙号＂首次在马里亚纳海沟南部获取的沉积物柱状样（JL7KGC01A）进行了涂片观察、粒度、黏土矿物和稀土元素组成分析。结果表明：沉积物为典型深海黏土沉积。根据沉积物的粒度、黏土组分和稀土元素含量变化以及不同程度的δCe和δEu异常将该沉积物柱状剖面分为明显的上下两个沉积层段,即：1.8～2.41m段与0.03～1.8m两个层段。下部层段（1.8～2.41m）相比上部层段（0.03～1.8m）,沉积物平均粒径较粗,蒙脱石/伊利石比值较高,稀土元素含量低且具有弱的Ce负异常和Eu正异常,表明该段沉积物受到较多的火山物质的影响。结合年代学分析认为研究区沉积物在2.2 Ma发生明显转变,2.2 Ma之前沉积物物源以附近火山物质为主,2.2 Ma之后物源仍以火山物质为主,但陆源物质供应逐渐增加。物源的转变暗示着本区在2.2 Ma之前火山活动较为频繁。

黑云杉嫩枝扦插育苗技术的研究

采用全光自动喷雾扦插育苗设备进行了黑云杉半木质化嫩枝扦插育苗试验。3年研究结果表明 ,在辽宁省东部地区气候条件下 ,以ABT200mg/kg浸插穗30～50min,生根率达到78.3%,而且根系发育良好 ;嫩枝插穗生根率比带部分硬枝的插穗生根率高49%,两者差异达显著水平 ;河沙插壤比锯末插壤生根率提高11.2%。嫩枝插穗扦插后 ,25d形成愈伤组织 ,40d左右出现根状凸起 ,50d生根。秋季起苗 ,沙藏越冬 ,翌年移植成活率高达92.5%,当年新梢生长量6.6cm。

马里亚纳俯冲系统的构造特征

西太平洋马里亚纳俯冲带具有典型的"沟-弧-盆"体系,是由太平洋板块向西俯冲到菲律宾海板块之下形成的洋-洋俯冲带。前人研究成果为理解该区上覆板块地壳结构、弧前蛇纹岩化过程、岛弧及弧后岩浆作用、俯冲板块形态及其相关俯冲动力学过程提供了良好的约束。本文对马里亚纳地区现有研究成果,特别是构造研究内容,进行了总结,发现马里亚纳俯冲带的三维精细构造特征并没有得到很好的厘定,导致马里亚纳弧后扩张的动力学机制存在较大争议。这主要是因为缺乏观测数据以及反演方法的局限性。为此,未来围绕马里亚纳俯冲带的构造特征研究,应首先开展长期系统的海底观测。

马里亚纳海槽热液活动区玄武岩的岩石地球化学特征

对拖网采自马里亚纳海槽热液活动区 (18°N附近 )的 8个玄武质岩石样品进行岩石地球化学初步研究。岩石富集 L IL E和 L REE,稀土分布型式呈右倾图式 ,L a N=10 .6 8～ 2 2 .6 4 ,(L a/Yb) N=1.6 1～ 2 .4 7,并略显 Eu正异常。在相对于原始地幔的标准化微量元素分布图中 ,7个样品具较明显的 Nb亏损和 Zr、Hf富集 ,而 1个样品不具 Nb的亏损 ;HFSE/HFSE、L IL E/HFSE、L IL E/L IL E等微量元素比值大都在 N- MORB和 EMI2个地幔端员组分间变化。这表明岩浆起源于受俯冲组分改造或影响的上地幔 ,且地幔源区存在明显的化学不均一性。与冲绳海槽玄武岩相比 ,马里亚纳海槽玄武岩的 Nb亏损明显减弱 ,暗示俯冲组分对地幔源区的影响程度也随之减弱 ,这反映出处于弧后张裂阶段的冲绳海槽与处于从弧后张裂向海底扩张过渡阶段的马里亚纳海槽 。

马里亚纳海槽热液区岩石矿物学和岩石化学特征研究

马里亚纳海槽中央轴裂谷中的小扩张脊部位 ,广布火山喷发的玄武岩体 ,海底热液硫化物就是从这些岩体的裂隙中喷溢堆积起来的。利用我国“大洋一号”船拖网所获岩样进行了矿物学和岩石化学特征研究 ,认定为高铝低钾的大洋底玄武岩或拉斑玄武岩系列和钙 -碱玄武岩。

北美白云杉、黑云杉在中国的引种研究

云杉属 (Picea)树种是高大乔木 ,生态适应性强 ,利用价值高 ,近 2 0 0年来欧、亚、美作了大量的引种栽培工作。很多国家已将它们作为主要的造林树种和珍贵的绿化观赏树种 ,因此研究云杉属的引种 ,对促进林业生产和国民经济发展 ,具有重要意义。主要探讨了北美最重要的用材树种白云杉、黑云杉在国外的研究现状及发展趋势以及在我国的引种可能性、引种历史、现状、存在的问题及展望 ,以期对今后的引种。

马里亚纳海沟俯冲带深地震现状对马尼拉海沟俯冲带的研究启示

综述了马里亚纳海沟俯冲带二维（2D）和三维（3D）深地震探测的研究进展, 要点如下： 1）伊豆-小笠原岛弧下方玄武质火山岩的物质成分基本一致, 中地壳的速度特征与陆壳相似, 岛弧底部镁铁质到超镁铁质的壳幔过渡层（crustmantle transition layer, CMTL）通过拆沉（delamination）等作用返回地幔, 实现由岛弧到陆壳的演化; 2）不同年龄的洋内岛弧具有不同的速度结构特征, 说明它们的地壳密度不同, 可用不同的模型来解释; 3）岛弧体系中速度结构及演化历史在时间和空间上的特征变化, 揭示了俯冲开始时洋壳和地幔的属性以及俯冲开始的原因.马尼拉海沟与马里亚纳海沟相比, 虽然地质背景不同, 但研究方法可以借鉴.今后的马尼拉海沟俯冲带探测的重点包括海底地震仪2D/3D 联合探测、海底电磁探测, 以及天然地震的长期观测等.马尼拉海沟项目的实施将加深对俯冲带运行机制的认识.

马里亚纳海沟挑战者深渊南部7000m水深处发现硅藻化石软泥

在马里亚纳海沟"蛟龙号"载人深潜器海试区约7000m水深的海底,发现了硅藻化石软泥沉积物,为中国首次在此大深度船载采集到硅藻化石软泥。室内硅藻化石分析显示,重力柱状样顶部约10cm厚的软泥为大筛盘藻Ethmodiscus rex硅藻软泥。化石主要由大筛盘藻组成,呈碎片状,数量巨大,并伴生有Azpeitia等热带远洋浮游种类。硅藻化石软泥发育表明,本区曾发生过E.rex勃发事件,具有重要的古海洋学和古生物学研究意义。

九州帕劳海脊地壳结构及其形成演化的研究综述

九州-帕劳海脊(KPR)位于菲律宾海中央,近南北走向。形成于太平洋板块向西的俯冲,裂离于帕里西维拉海盆和四国盆地的弧后扩张,是老的伊豆-小笠原-马里亚纳岛弧(IBM)的残留弧。裂离期间同时受到垂向旋转应力和水平挤压力的共同作用,这是形成九州-帕劳海脊现今狭长的几何形态的主要原因之一。九州-帕劳海脊南北部地壳结构可总结为P波波速为7.1～7.3km/s下地壳;P波波速为6.1～6.3km/s的中地壳;P波波速为4.5～5.5km/s上地壳。九州-帕劳海脊北段,30°N以北区和25°N以南区的地壳厚度普遍在10～15km,25°～30°N之间的地壳厚度普遍大于15km。九州-帕劳海脊的中段的地壳厚度变化较大,而且未识别出中地壳的存在,为不成熟的岛弧地壳。海脊南段与北段相似,具三层的地壳结构,但地壳厚度小于北侧,基本上大于10km。整个九州-帕劳海脊处的地壳厚度普遍厚于两侧海盆的地壳厚度。

深渊着陆器技术研究及马里亚纳海沟科考应用

海斗深渊是指海洋中深度超过6 000 m的区域,占据了海洋底部45%的深度范围,是海洋生态系统的重要组成部分,海斗深渊科学代表着当前海洋研究最新的前沿领域。面向海斗深渊科学近海底长时探测与采样应用需求,介绍了我国自主研制的7 000 m级"天涯"号、"海角"号深渊着陆器系统,针对深渊着陆器的装备特点,重点研究了生物原位观测、微生物富集与固定、生物诱捕及沉积物取样等技术。描述了深渊着陆器在马里亚纳海沟开展的试验和科考应用,验证了着陆器及采样技术的可行性、有效性及其对深渊科考的适用性,并取得了多项科考成果。