新疆乌鲁木齐二叠系湖相微生物白云岩成因

新疆乌鲁木齐地区养牛场剖面中二叠统芦草沟组以发育浅湖至半深湖背景下的中层深灰色、灰色碳酸盐岩、粉砂岩、细砂岩与中、厚层灰黑色泥岩、油页岩的互层沉积为特点.湖相碳酸盐岩以微晶白云岩为主体,其次为微晶灰岩.微晶白云岩主要由白云石、铁白云石及少量方解石等组成,常混有泥质组分且富含有机质.镜下观察白云石主要为微晶(＜4μm)及微亮晶(4-10 μm),极少数为亮晶(＞10μm).扫描电镜分析发现微晶白云岩中存在微球状(直径约9μm)、微棒状(长度约0.3～1.2μm)及微米级它形(＜ 5μm)等3种微形貌的白云石,其中微米级它形白云石在白云岩中占绝大多数.在微晶灰岩中还发现了直径约70-150nm,形态与球菌相似的纳米微粒,具有微生物矿化的特征.研究区白云岩Sr丰度及Sr/Ca比总体持平或略高于微晶灰岩,Mn丰度远高于微晶灰岩,C、O同位素均高于微晶灰岩,暗示了白云岩可能形成于比微晶灰岩更深及盐度更大的水下还原环境,二者之间缺乏明显的交代关系.芦草沟组白云岩的δ13CPDB介于9.2 ‰～15.6‰,强烈正偏的δ13CPDB可能是产甲烷古菌的代谢活动引起有机质碳同位素分馏的结果.以上特征表明,研究区芦草沟组白云石的沉淀可能与产烷带厌氧微生物的代谢活动引起的甲烷生成作用有关.     

Composition and distribution of meiobenthos in amursky bay (peter the great bay, the east sea)

Qualitative and quantitative composition of meiobenthos was studied in Amursky Bay (Peter the Great Bay, the East Sea). Ten taxonomic groups were found, where nematodes were dominant. Density of meiobenthos in ground sediments of the Bay were not uniform, and the average density was measured at 126.4±62.3 ind. m^-2. 56 species of nematodes were detected, and dominant species wereSabatieria palmaris, Paracanthonchus macrodon, Sphaerolaimus limosus, S. gracilis andOncholaimium ramosum. Five taxocenes of nematodes were allocated based on the results of cluster analysis and species domination according to density. Low diversity in species composition of nematodes was noted in the northwestern part of the Bay, which is a zone of desalination, and in the eastern part, which is exposed to household drains.     

MALBAC技术扩增微生物群落基因组的效率评估

环境样品的低生物量是微生物宏基因组学研究面临的首要挑战,通过基因组扩增技术来满足高通量测序对DNA样品量的需求是最常用的解决策略。MALBAC(Multiple Annealing and Looping Based Amplification Cycles)基因组扩增试剂盒最初为扩增和研究哺乳动物的单细胞基因组而研发。本文中,我们通过人工构建的微生物群落来检测该试剂盒在微生物宏基因组扩增方面的效率和应用可行性。结果表明,每个标准反应中,10 pg的DNA模板量足以满足MALBAC试剂盒对样品扩增的需要。每个标准反应DNA模板用量为10和100 pg时,所扩增DNA样品的基因组覆盖度与原始未扩增样品表现出高度的一致性,证明MALBAC试剂盒扩增效果的高度稳定性和一致性。常用的GenomePlex全基因组扩增试剂盒使我们可以在每个标准反应DNA模板量为100 pg的条件下扩增获得足够的DNA样品,但是结果表明该参照试剂盒无法有效的实现对群落中低丰度细菌菌株基因组的线性扩增。对于MALBAC试剂盒和参照试剂盒而言,在扩增高GC含量的微生物物种基因组DNA方面效率低下。我们的实验结果表明MALBAC试剂盒在高效扩增环境样品宏基因组DNA方面的可行性,但对该试剂盒在扩增环境样品中高GC含量微生物物种方面的适用性存在疑虑。     

Marine spatial planning from the perspective of a small seaside community in Ireland

Marine spatial planning (MSP) is advocated as a means of managing human uses of the sea in a manner that is consistent with the maintenance of the ecological goods and services of the marine environment. Support for the process is evident at international and national levels but the degree to which it is acceptable to local level stakeholders is not clear. An Daingean (formely Dingle) is a small sea-oriented town situated on the southwest coast of Ireland in which marine-based tourism and other relatively new uses of the sea are pursued along side traditional fishing activities. Stakeholders in An Daingean are found to be positively disposed to a local process of MSP that incorporates meaningful local involvement.     

Floating and fixed artificial habitats: Spatial and temporal patterns of benthic communities in a coral reef environment

While natural marine habitats with motion capabilities, e.g., kelps and seaweeds, have been studied alongside their associated fouling communities, little is known of the effect of motion on the communities of floating artificial habitats such as buoys, rafts, and pontoons, particularly in tropical systems. Hydrodynamic features greatly differ between floating and fixed artificial substrata, which in turn affect the structure of their associated communities. This study tested the hypothesis that floating and fixed artificial installations in a tropical reef system (Eilat, Red Sea) would support different benthic communities throughout space and time. Specifically, we examined differences in communities recruited onto settlement plates between floating and fixed installations deployed at three different sites, along a two-year monitoring period. The three sites exhibited distinct differences in species assemblages between the monitoring dates (6, 12, 18 and 24 months post deployment), mainly between the first and the last two dates. The average level of dissimilarity between floating and fixed installations increased over time at all sites. Over 50% of the dissimilarity between the floating and fixed installations resulted from five taxonomic groups i.e., bryozoans, bivalves, barnacles, sponges, including the amount of bare space on the settlement plates. The contribution of these groups to the dissimilarity changed both temporally within each site, and spatially among sites. The observed differences were related to the hydrodynamic characteristics of floating and fixed habitats, interacting with biotic features such as predation, successional processes and seasonality; and abiotic features including small-scale spatial changes, light, and position in the water column.     

海洋生境刀鲚菌群PCR-DGGE指纹图谱构建及分析

为了分析海洋生境刀鲚(Coilia nasus)体内及生长环境菌群结构,作者采用免培养16S r DNA的PCR-DGGE指纹图谱技术,对刀鲚鳃、肠道壁、肠道内容物及水体环境中的菌群结构进行了对比分析。结果表明:变性梯度为35%~55%、浓度为8%的聚丙烯酰胺凝胶,150V 60℃下电泳10 h,DGGE带谱的分离效果较好;刀鲚鳃、肠道壁、肠道内容物及水体样品指纹图谱上分别显示出24、19、14和29条信号强度不同的条带;相同样品重复组细菌结构相似度在80%以上,差异不显著;不同样品之间,刀鲚鳃与海水聚为一支,具有较高的相似度为52%,肠壁与肠内容物相似度为41%。样品菌群主要以未培养菌为主,主要包括变形菌、放线菌和厚壁菌。本文首次成功构建海洋生境刀鲚菌群16S r DNA的PCR-DGGE指纹图谱。     

Macrofaunal communities in the habitats of intertidal marshes along the salinity gradient of the Schelde estuary

The macrobenthos is important in benthic remineralization processes; it represents a trophic link and is also often used as a bio-indicator in monitoring programs. Variations of the environmental parameters strongly influence the structure of the macrobenthic communities in the marshes and since macrobenthos is the most important food item for marsh-visiting fish species in the Schelde, the variation in food resources can have a strong effect on the higher trophic level. The present study deals with the variation in macrobenthic communities in different habitats of intertidal marshes along the salinity gradient and the differences between the marsh creeks and the intertidal part of the estuary. The study measured density and species richness together with the biomass, and sampled a large intertidal channel and a smaller creek within five marshes along the salinity gradient of the Schelde estuary every six weeks between May and October in 2000.     

天然气水合物系统的环境效应

环境效应是天然气水合物科学体系中重要一环,同时,有关该领域的调查研究也是人类安全、环保、经济、科学地利用水合物资源的可靠保证。海底天然气水合物所孕育的独特的生态系统、与之关联的重大地学、环境问题以及资源的勘探开发均是充满魅力而又富有挑战的科学新领域。梳理了当前全球范围内有关水合物环境效应的大部分研究工作,综述了与天然气水合物环境有关的生物效应、化学效应和物理效应的研究现状及内容,着重强调了与该领域相关的基础问题和焦点问题,展望了该领域未来发展的趋势,希望藉此为我国的水合物环境效应调查与评价工作向纵深推进提供参考依据,并能引起广大研究者的兴趣与重视。     

南海北部台西南盆地973-4岩芯碳的地球化学特征

对南海北部台西南盆地天然气水合物潜在区(973-4岩芯)碳的形态、含量和稳定同位素组成进行了分析,并探讨了成岩环境因素和细菌种群与碳地球化学行为的关系。结果显示:(1)TOC含量为0.4%~1.3%,δ~(13)CTOC为–26.7‰~–23.9‰,说明973-4岩芯主要为陆源有机质,能够满足微生物产甲烷的需要;DIC和δ~(13)CIC的垂向变异及其显著负相关,指示:973-4岩芯560~890 cm深度段有SO42–驱动的AOM反应。(2)p H、Eh、沉积物粒径等成岩环境参数与TOC、IC、δ~(13)CTOC、δ~(13)CIC等碳地化参数显著相关。(3)细菌种群与DIC、δ~(13)CIC显著相关。结论认为:(1)973-4岩芯碳的地化行为与天然气水合物成藏存在明显响应关系。(2)成岩环境参数的垂向变异与碳的地球化学特征密切相关。(3)细菌种群对碳的地化参数变异有着显著影响。     

Biodiversity of meiofauna in the intertidal khe nhan mudflat,can gio mangrove forest,vietnam with special emphasis on free living nematodes

The ecological aspect of meiofaunal communities in Can Gio mangrove forest, Ho Chi Minh city, Vietnam has not been investigated before. The composition, distribution, density and biodiversity of meiofaunal communities were studied along an intertidal transect at the Khe Nhan mudflat. Each time, three replicate samples were collected in four stations along a transect following the water line from low tide level up to the mangrove forest edge. In total, 18 meiofaunal taxa were found with the dominant taxa belonging to Nematoda, Copepoda, Sarcomastigophora and Polychaeta. The densities of meiofauna ranged from 1156 inds/10 cm² to 2082 inds/10 cm². The increase in densities from the mangrove forest edge towards the low water line was significant. Along the mudflat transect, the biodiversity (expressed by different indices) was relatively high at different taxonomic levels but did not vary significantly along the mudflat except for taxa richness. Eighty nematode genera belonging to 24 families with Comesomatidae having the highest abundance 33.8 % were found.Theristus andNeochromadora decreased in densities from the lower water line towards the mangrove forest edge, whileParacomesoma andHopperia are typical and more abundant at the middle of the mudflat.Halalaimus increased from high on the mudflat to the low water line.