生物标志物重建浮游植物生产力及群落结构研究进展

海洋浮游植物生产力和群落结构在地质年代中的变化对深入理解碳循环的演变规律和机理有着重要的意义.生物标志物方法作为一种较新的研究手段,其含量与比值的变化被广泛用于浮游植物生产力与群落结构变化的重建.讨论了生物标志物方法在各大洋及我国边缘海的应用现状,提出了生物标志物的细胞产生量及其在环境中的保存效率的2种主要不确定因素,使目前多参数生物标志物方法只能够半定量地重建古生产力与群落结构的变化.针对我国边缘海,提出有必要通过现场调查和实验室培养建立生物标志物含量(比值)与浮游植物生产力(群落结构)的定量关系式,以达到能够定量重建生产力和群落结构变化的目的.     

Detection and Classification of Phytoplankton Deposits Along an Estuarine Gradient

Phytoplankton deposition onto sediments affects trophic structures, sedimentary nutrient fluxes, and dissolved oxygen concentrations in coastal ecosystems. Deposition can occur as distinct events that are highly variable over space and time, necessitating detection methods that have similarly high resolution. We present an assessment of a novel rapid detection method that combines water-column and benthic fluorometry with surficial sediment sampling to identify phytoplankton deposition, as implemented in a 2-year study of a Florida estuary (24?monthly collections at 14 locations). Maximum water-column chlorophyll concentration, average benthic chlorophyll fluorescence, and the proportion of centric vs. pennate diatoms at the sediment?Cwater interface were each fitted to sine functions to represent phytoplankton bloom cycles. The phase offsets among the three fitted sine functions were varied to maximize fit to the 336 observations. The fitted cycles were divided into four classes that separate dominance by benthic microalgae from early, late, and post-phytoplankton depositional states. Best-fitting cycles for the proportion of centric diatoms were consistently offset from water-column chlorophyll cycles, indicating peak deposition occurred after peak phytoplankton blooms. Phytoplankton deposition dominated the upstream region of the studied estuary and was associated with reduced dissolved oxygen concentrations. Benthic algae dominated in downstream regions, particularly during low freshwater flow conditions when light absorption by colored dissolved organic matter was low. This approach produced repeatable and consistent patterns that agreed with expected relationships and was practical for sampling with high spatial and temporal resolution.     

Impacts of SW Monsoon on Phytoplankton Community Structure Along the Western Coastal BOB: an HPLC Approach

The major Indian rivers bring significant amount of freshwater along with inorganic nutrients and sediment load in to the northern Bay of Bengal (BOB) during the southwest monsoon (SWM); the southern bay does not experience equal freshening. This contrasting pattern may considerably impact the physicochemical features and phytoplankton community composition in this bay and was investigated during a coastal cruise during the SWM covering eight river plumes from both northern and southern bay; phytoplankton pigments and physicochemical parameters were analysed from different depths (0, 10, 25, and 50 m). Significant freshening, stratification and warmer waters were noticed in the northern bay relative to its southern part. Phytoplankton pigment analysis and diagnostic pigment-based size class analysis revealed the dominance of microphytoplankton (mainly diatoms) in the northern bay and were mostly confined to the surface waters. Their abundance was positively correlated with dissolved silicate (DSi) concentrations and inversely with salinity. Nanophytoplankton and picophytoplankton (prymnesiophytes, chrysophytes and cyanophytes) were mostly noticed in the subsurface waters and dominated the southern bay. This finding suggests that the dominance of microphytoplankton in the northern bay may significantly contribute to higher particle flux which has been reported earlier. Therefore, any modification in future river discharge, which is in turn related to the intensity of Indian summer monsoon, will alter the phytoplankton community structure in the coastal BOB and may be further cascaded to the other vital ecosystem components like fisheries resources, organic carbon export flux and benthic production.     

水库水文情势与浮游植物群落结构

综述和讨论了当前水库水文情势对浮游植物群落的影响研究,主要是水文情势对浮游植物数量、种类组成、物种多样性和群落的空间格局包括垂直和水平分布以及群落演替的影响.     

静17块原油流体性质及对开采效果的影响

研究了辽河油田静17块油藏高黏原油流体性质及其对开采效果的影响.静17块油藏具有含蜡量高(22.56%～40.68%)、凝固点高(44～59°C)、黏度大、屈服值小等特点.凝固点随着含蜡量的增加而逐渐上升,例如当含蜡量大于10%,凝固点高于35°C,含蜡量为40%时,凝固点约为54°C.黏度随温度升高而降低,如温度为40°C时,黏度为1.343 7×109 mPa·s,温度为60°C时,黏度为1.094 9×102 mPa·s.利用油藏数值模拟方法研究了不同注水温度开采条件下,5口水平井的产量变化.结果表明,注水温度为60°C时,其产油量比注水温度为20°C时的产油量提高了20%～30%.由实验结果得知,60°C是一个重要的临界温度,在这个温度以上,原油呈牛顿流体状态,蜡晶不会析出,黏度明显降低.因此,保持油藏地层温度高于60°C,降低流体黏度,是提高采收率的一个重要条件.     

Incorporation of Leucine and Thymidine by Estuarine Phytoplankton: Implications for Bacterial Productivity Estimates

Leucine and thymidine incorporation were examined in size-fractionated estuarine communities and in cultures of phytoplankton known to use dissolved organic nitrogen (DON). Cultured phytoplankton species were used to establish that phytoplankton took up leucine and thymidine into protein and DNA, respectively. Subsequently, incorporation of leucine and thymidine was measured in size-fractionated populations collected from the Lafayette River, VA, a eutrophic estuary where resident populations contain bloom-forming phytoplankton known to take up DON, and the Gulf of Mexico during a bloom of the mixotrophic red tide dinoflagellate, Karenia brevis. We examined the efficacy of size fractionation for determining phytoplankton versus bacterial incorporation of leucine and thymidine under conditions employed during bacterial productivity bioassays, and antibiotics were used to distinguish between bacterial and phytoplankton incorporation in cultured and natural populations. Results suggest that cultures and natural assemblages of phytoplankton can take up both leucine and thymidine when supplied at low concentrations (10 and 12 nmol L⁻¹, respectively) and during short incubations (15 min to 1 h). In natural populations, up to 95% of the leucine and thymidine incorporation during short bioassays was recovered in the >5.0-μm size fraction that contained ≤4.2% of the bacterial biomass.     

南黄海北部晚更新世以来浮游植物生产力和群落结构变化的生物标志物记录

冰期—间冰期引起的海平面变化会导致黄海的沉积环境和生态系统发生巨大变化。通过多参数生物标志物法对取自南黄海北部71.2m长的DLC70-3岩心进行研究,获得晚更新世以来的浮游植物生产力和种群结构变化信息,并探讨影响其变化的可能因素。结果表明,晚更新世以来,DLC70-3岩心的浮游植物初级生产力和单一藻类生产力总体上呈现一致的变化趋势,在MIS 5e和MIS 3c时期最高,而在其他层位较低。浮游植物种群结构的变化主要表现为颗石藻在MIS 5e和MIS 3c相对含量增加,硅藻和甲藻相对含量下降,而颗石藻在其他层位含量为0。这都归因于高海平面时黄海暖流的入侵导致黄海盐度发生了较大的变化。     

Degradation of Microbes for the Crude Oil Contaminants

Production and storage-transportation of crude oil can not only give rise to soil pollution but also destroy ecological environment. Degradation of microbes for oily soil was studied with the instnunent, Geofina Hydrocarbon Meter (GHM), by experimental analysis qualitatively and quantitatively in the paper. Analytical result showed that the crude oil could be considerably degraded by eating-oil microbes in oily soil and the number of eating-oil microbes increased while the working hours of oil-well rising. As a result, contaminated oil could be degraded more quickly by a lot of eating-oil microbes in the soil. At the same time, the degradation rate of contaminated oil increased gradually as the time went on. In addition, amount of gaseous component in the oily soil samples increased with degraded time and the microbes could selectively consume contaminated oil strongly, so biedegradation might alleviate the degree of contamination and destruction to the soil and environment in the process of oil product     

柴达木盆地原油成因研究

柴达木盆地是我国西北地区大型含油气盆地之一.经过50年的油气勘探,已在该盆地发现18 个油田,它们主要分布柴西地区,对其成因一直是人们关注的问题.通过对这些油田原油的物理化学性质、油源对比和成因机制综合研究表明,柴西地区和柴北地区是两个不同的成油单元,它们原油的形成环境、母质类型、成熟度和油源都是截然不同的.并且认为,虽然柴达木盆地第三系生油岩有机碳含量较低,但是其形成于强还原和咸水环境,有利于生物脂类的保存,生物脂类与可溶有机质和干酪根一起在低成熟阶段可以生成大量石油,是柴西地区未熟低熟原油形成的主要途径.     

Spreading of Technical Oils and Crude Oil on the Water Surface

Doklady Earth Sciences - A mathematical model of oleic spot propagation based on the laws of conservation of mass and the total energy of the system is constructed. Compact solutions of this model...     

艾比湖地区冻融作用对土壤微生物数量和群落结构的影响

通过对艾比湖地区冻融阶段7个典型样地野外采样和室内分析,研究了冻融作用条件下土壤微生物数量与土壤性质的关系、土壤微生物数量变化特征和土壤微生物群落结构的变化特征. 结果表明：不同冻融阶段,不同种类微生物数量受到不同土壤理化因子的制约. 1月,细菌数量与土壤有机质含量呈显著正相关(P<0.05),真菌数量与土壤含水量和土壤有机质含量呈极显著正相关(P<0.01),与土壤全氮和土壤孔隙度呈显著正相关(P<0.05);3月,只有真菌数量与土壤含水量呈极显著正相关(P<0.01);4月,放线菌数量与土壤有机碳和全氮含量呈显著正相关(P<0.05),然而与土壤pH值呈显著负相关(P<0.05). 总体来讲,冻结期土壤微生物数量较低,冻融后期(4月)达到峰值,其中,7 a 撂荒地的微生物数量最高,3 a撂荒地最低. 在研究区寒冷季节,微生物类群中放线菌占主导地位(81.9%);融化阶段,则是细菌占主要地位(52.1%~53.9%).     

我国不同原油裂解成气动力学研究

提供了我国海相、湖相原油的黄金管裂解成气热模拟实验数据和裂解成气的动力学参数。对比分析典型样品裂解生气特征、升温速率与温度对油裂解成气的影响表明:我国海相、湖相原油裂解成气门限温度、消亡温度差异不大,但与国外样品差异明显;源内和源外原油裂解成气过程差别明显,源内原油热稳定性弱于源外原油热稳定性,在油裂解气评价中应该考虑排烃效率的影响;温度是原油裂解的主要控制因素,温度高于180℃时,原油裂解过程主要在10 Ma内完成,且液态烃消亡温度要高于200℃。本次研究的实验结果、动力学参数及相关结论可供盆地模拟和油藏勘探工作采用和借鉴。     

油藏原油微生物降解的氮同位素分馏效应

选取辽河油田冷东地区来自Es3烃源岩不同性质原油,测定氮同位素比值,试图分析生物降解过程中原油氮同位素的分馏作用,探讨含氮化合物组成的变化机理。正常原油与相应干酪根的氮同位素比值接近,δ15N分布在4.0‰左右。遭受生物降解的原油,氮同位素比值明显增加,δ15N接近或超过10.0‰。比较遭受不同程度微生物降解自然系列的原油,氮同位素比值的变化与降解程度相联系。微生物降解过程中发生氮同位素分馏作用这一事实暗示降解原油中含氮有机化合物在降解过程中参与了代谢。     

石油对金的活化迁移作用的研究初探

在测定原油中金浓度和对相关岩心样品中金分析的基础上，初步研究了原油对岩石中金的活化迁移作用。结果表明，原油中的金浓度与对应的岩心样品中含金量呈正相关性，原油对岩石中金具有较强的活化迁移作用，为原油对金的相互作用的研究提供了重要的实验基础。     

鄂尔多斯盆地天环坳陷南段侏罗系原油油源分析

天环坳陷南段位于鄂尔多斯盆地西南部,跨西缘冲断带和天环坳陷两个构造单元,地质条件复杂。近年来针对该区侏罗系低幅度构造岩性油藏的勘探取得了重大突破,钻遇多口工业高产油流,但目前对侏罗系油气的来源问题仍存在不同的认识,制约了勘探的进一步深入。应用色谱/质谱和碳同位素等分析方法和手段,对侏罗系原油与三叠系延长组长4+5段、长6段和长7段3套烃源岩从生物标志化合物、碳同位素等方面进行对比研究,并结合侏罗系油气成藏特征,探讨了侏罗系原油的油源。结果表明:天环坳陷南段侏罗系原油和长6段、长7段烃源岩在母源性质、沉积环境、成熟度等方面具有相近似的特征,二者具有较好的亲缘关系;区域性不整合面、裂缝成为沟通侏罗系储层与长6段、长7段油源的运移通道;侏罗系原油主要来源于长6段和长7段烃源岩。     

塔里木盆地西南坳陷柯东1号构造白垩系原油特征

柯东1号构造是塔里木盆地西南坳陷昆仑山前发育的断鼻型圈闭,钻探kd1井白垩系获高产工业油气流.原油地球化学特征表明,其为高含蜡中质成熟原油,甾烷中C27、C28、C29甾烷呈反“L”型分布,以C29甾烷含量高为特征,萜烷类C29、C30重排霍烷、C30未知萜烷、C24四环萜烷、Ts含量相对较高.生物标志物特征表明,该原油来源于二叠系烃源岩.据原油成熟度分析认为,该原油高分子量芳烃和低分子量的轻烃是烃源岩分别在成熟阶段与高-过熟阶段产物.因此,kd1井白垩系原油是二叠系烃源岩成熟期、高熟期两期充注的混合原油.     

高邮凹陷韦庄地区原油吡咯类含氮化合物运移分馏效应

高邮凹陷韦庄地区具有正常和轻微生物降解2类原油, 对油气运移方向一直存在争议.根据2类原油中含氮化合物浓度、屏蔽型含氮化合物的相对含量与反映原油生物降解的地化参数C₂₁-/C₂₂+、Pr/nC₁₇等nC₁₇物降解作用对该区原油中含氮化合物的相对含量及其分布影响不明显, 运移作用仍然是造成含氮化合物分馏的主要因素.自东向西、东北向西南方向, 韦X11井、韦6 - 2井、韦5 - 19井、韦8井原油中屏蔽型咔唑的相对含量依次增大, 分别为11.6 2 %, 10.6 6 %, 12.70 %, 13.88%;暴露型咔唑的相对含量则表现出相反的变化趋势, 分别为30.6 0 %, 2 8.5 6 %, 2 6.4 3%, 2 4.6 2 %.由此明确了本区油气自东、东北方向向西、西南方向注入, 深凹带和车逻鞍槽提供了主要油源.      

Modeling the Effects of Tidal Energy Extraction on Estuarine Hydrodynamics in a Stratified Estuary

A 3-D coastal ocean model with a tidal turbine module was used in this paper to study the effects of tidal energy extraction on temperature and salinity stratification and density-driven two-layer estuarine circulation. Numerical experiments with various turbine array configurations were carried out to investigate the changes in tidally averaged temperature, salinity, and velocity profiles in an idealized stratified estuary that connects to coastal water through a narrow tidal channel. The model was driven by tides, river inflow, and sea surface heat flux. To represent the realistic size of commercial tidal farms, model simulations were conducted based on a small percentage (less than 10 %) of the total number of turbines that would generate the maximum extractable energy in the system. Model results show that extraction of tidal in-stream energy will increase the vertical mixing and decrease the stratification in the estuary. Installation of in-stream tidal farm will cause a phase lag in tidal wave, which leads to large differences in tidal currents between baseline and tidal farm conditions. Extraction of tidal energy in an estuarine system has stronger impact on the tidally averaged salinity, temperature, and velocity in the surface layer than the bottom layer even though the turbine hub height is close to the bottom. Finally, model results also indicate that extraction of tidal energy weakens the two-layer estuarine circulation, especially during neap tides when tidal mixing is weakest and energy extraction is smallest.     

Modeling the Effects of Future Outflow on the Abiotic Habitat of an Imperiled Estuarine Fish

Future development and climate change pose potentially serious threats to estuarine fish populations around the world. We examined how habitat suitability for delta smelt (Hypomesus transpacificus), a state and federally protected species, might be affected by changes in outflow in the San Francisco Estuary due to future development and climate change. Forty years of sampling data collected during fall from 1967 to 2008 were examined to define abiotic habitat suitability for delta smelt as a function of salinity and water transparency, and to describe long-term trends in habitat conditions. The annual habitat index we developed, which incorporated both quantity and quality of habitat, decreased by 78% over the study period. Future habitat index values under seven different development and climate change scenarios, representing a range of drier and wetter possibilities, were predicted using a model which related estuarine outflow to the habitat index. The results suggested that each of the scenarios would generally lead to further declines in delta smelt habitat across all water year types. Recovery targets for delta smelt will be difficult to attain if the modeled habitat conditions are realized.     

Origin of Crude Oil in the Lunnan Region,Tarim Basin

<正>The oil source of the Tarim Basin has been controversial over a long time.This study characterizes the crude oil and investigates the oil sources in the Lunnan region,Tarim Basin by adopting compound specific isotopes of n-alkanes and biomarkers approaches.Although the crude oil has a good correlation with the Middle-Upper Ordovician(O_(2+3)) source rocks and a poor correlation with the Cambrian-Lower Ordovician((?)-O_1) based on biomarkers,theδ~(13)C data of n-alkanes of the Lunnan oils show an intermediate value between(?)-O_1 and O_(2+3) genetic affinity oils,which suggests that the Lunnan oils are actually of an extensively mixed source.A quantification of oil mixing was performed and the results show that the contribution of the Cambrian-Lower Ordovician source rocks ranges from 11%to 70%(averaging 36%),slightly less than that of the Tazhong uplift.It is suggested that the inconsistency between the biomarkers andδ~(13)C in determining the oil sources in the Lunnan Region results from multiple petroleum charge episodes with different chemical components in one or more episode(s) and different sources.The widespread marine mixed-source oil in the basin indicates that significant petroleum potential in deep horizons is possible.To unravel hydrocarbons accumulation mechanisms for the Lunnan oils is crucial to further petroleum exploration and exploitation in the region.