东南极戴维斯站企鹅粪土沉积物有机地球化学特征   总被引：1，自引：0，他引：1       下载免费PDF全文

黄婧  王新明  孙立广 《极地研究》2009,21(2):141-150

研究了位于东南极西福尔丘陵地区Gardner Island企鹅粪土的沉积泥芯DG2的分子地球化学组成特征。DG2沉积物的正烷烃以短链为主,主要来源可能为淡水湖相沉积的藻类和细菌输入。脂肪酸组分偶奇优势明显,以C16,C18和C24一元饱和脂肪酸为主,主要来源可能是浮游动物、细菌及水生苔藓;不饱和脂肪酸含量很低,以C18∶1(Δ9)为主,表明沉积源单一稳定,无大波动。醇类组分以高浓度的植醇、胆甾烷醇和胆甾醇为主,分别代表了植被和企鹅数量,指示了研究区域历史时期的生态变化。综合DG2的生物标志物特征,反映该沉积物的有机质主要来源于企鹅粪、细菌和藻类;沉积环境在不同深度也有变化,0-30cm为氧化环境,30-63cm为还原环境。  相似文献   

处理钻探孔内埋钻事故"气动"方法及实际应用     

聂新明 《化工矿产地质》2020,42(2):162-169

"气动"方法是一种处理钻探孔内埋钻事故的新型方法,本文从"气动"方法的原理和与之相配套的封闭钻孔环状空间孔口装置的结构入手,结合工程实例对地面定向水平井施工时发生卡埋钻事故的过程、原因深入分析,对事故成功处理的全过程和所具体使用的每一种处理方法进行了全面剖析,证明封闭钻孔环状空间孔口装置是一种装卸方便性能可靠的封孔设备,认为"气动"方法处理钻探孔内事故行之有效,可以广泛应用于煤田防治水地面定向多分支水平注浆孔钻探工程。  相似文献   

中国东南海域拟菱形藻属的新记录种和产毒种     

庞金秀  董焕嫦  李扬 《海洋学报》2018,40(12):120-128

拟菱形藻属（Pseudo-nitzschia）物种是一类备受关注的海洋有毒有害硅藻,我国相关研究仍然不足,已报道的物种多样性偏低,产毒物种也较少。为了解我国海域拟菱形藻属的物种多样性,阐述产毒物种信息,在我国东南海域建立了8个拟菱形藻单克隆培养株系,结合形态学和分子系统学数据,鉴定到2个物种:环孔拟菱形藻（Ps.circumpora C.H.Lim,C.P.Leaw&P.T.Lim）和多列拟菱形藻[Ps.multiseries（Hasle） Hasle],其中环孔拟菱形藻是我国的新记录种。利用高效液相色谱-质谱联用法检测了藻株的多莫酸（domoic acid,DA）特征,在5个多列拟菱形藻株系中检测到DA,单细胞产毒水平为1.01~96.11 fg。此外,利用卤虫（Artemia salina L.）和强额拟哲水蚤（Paracalanus crassirostris Dahl）对多列拟菱形藻的产毒株系（MC4177）进行诱导,发现能够提高其单细胞产毒水平,提高幅度在26~55倍。  相似文献   

青藏高原地气温差变化及空间分布   总被引：2，自引：0，他引：2  

张文纲  李述训  吴通华  庞强强 《地理学报(英文版)》2007,17(1):20-32

The difference between ground soil and air temperature （Ts-Ta） was studied by using the data of ground and air temperature of 99 stations over the Qinghai-Xizang （Tibet） Plateau from 1960 to 2000,and its spatial distribution and time changing tendency have been diagnosed by principal component analysis and power spectral analysis methods. The results show that the values of （Ts-Ta） are the maximum in June and the minimum in December. The first three loading eigenvectors, which reflect the main spatially anomalous structure of （Ts-Ta） over the Qinghai-Xizang Plateau, contain the contrary changing pattern between the northwestern and the southeastern regions, the pattern response of the sea level elevation and the geography, and the pattern response of the distribution of the permafrost. There are four patterns of time evolution including the patterns of monotonous increasing or decreasing trends, the basic stability pattern and the parabola pattern with the minimum value. （Ts-Ta） has a periodic variation about 2 years. According to the spatial distribution of the third loading eigenvectors of （Ts-Ta） over the Qinghai-Xizang Plateau in cold season, the permafrost response region and the seasonal frozen ground response region are identified.  相似文献   

Molecular and isotopic evidence for mixed-source oils in subtle petroleum traps of the Dongying South Slope,Bohai Bay Basin   总被引：1，自引：0，他引：1  

Sumei Li  Xiongqi Pang  Zhijun Jin  Maowen Li  Keyu Liu  Zhenxue Jiang  Guiqiang Qiu  Yongjin Gao 《Marine and Petroleum Geology》2010

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Development of oil formation theories and their importance for peak oil     

Mikael Höök  Ugo Bardi  Lianyong Feng  Xiongqi Pang 《Marine and Petroleum Geology》2010

This paper reviews the historical development of both biogenic and non-biogenic petroleum formation. It also examines the recent claim that the so-called “abiotic” oil formation theory undermines the concept of “peak oil,” i.e. the notion that world oil production is destined to reach a maximum that will be followed by an irreversible decline. We show that peak oil is first and foremost a matter of production flows. Consequently, the mechanism of oil formation does not strongly affect depletion. We would need to revise the theory beyond peak oil only for the extreme — and unlikely — hypothesis of abiotic petroleum formation.  相似文献   

不同来源有色溶解性有机物光化学/微生物降解过程     

张怡晅  庞锐  任源鑫  程丹东 《湖泊科学》2022,34(5):1550-1561

城市非点源污染向水生生态系统中输入大量的溶解有机物(DOM),对生态系统健康产生重要影响.有色可溶性有机物(CDOM)是广泛分布于自然水体中的一类成分和结构复杂、含有多种高活性化学官能团的大分子聚合物,是DOM的重要组分,对水生生态系统健康、能量流动及生物地球化学循环有重要影响.光化学反应和微生物代谢过程被认为是控制水体CDOM转化、降解和循环的主要影响因素.然而,对城市化如何影响CDOM组成以及光化学和微生物如何相互作用影响城市水体CDOM动态的理解是不足的.因此,为评估光化学过程和微生物代谢对不同城市水体CDOM降解与转化的贡献,解析不同城市水体CDOM光化学/微生物降解作用机理,本研究在英国伯明翰选择3类具有典型DOM来源的水体样本,通过实验室9 d受控培养实验,对比分析光化学以及微生物影响下CDOM来源和组成的变化.结果表明:(1)城市河流由于接受上游污水排放及较短的水力滞留时间,含有丰富的芳香性碳,其CDOM光化学活性明显高于湖泊,光化学降解率为16.60%;(2)城市湖泊CDOM受人类活动影响,自生源类荧光成分富集,生物活性高,在微生物培养过程中CDOM增加了62.16%,...  相似文献   

Complex origins of silicate veinlets in HED meteorites: A case study of Northwest Africa 1109          下载免费PDF全文

Run‐Lian Pang  Ai‐Cheng Zhang  Ru‐Cheng Wang 《Meteoritics & planetary science》2017,52(10):2113-2131

We report on the petrography and mineralogy of three types of silicate veinlets in the brecciated eucrite Northwest Africa (NWA) 1109. These include Fe‐rich olivine, Mg‐rich olivine, and pyroxene veinlets. The Fe‐rich olivine veinlets mainly infill fractures in pyroxene and also occur along grain boundaries between pyroxene and plagioclase crystals, in both nonequilibrated and equilibrated lithic clasts. The host pyroxene of Fe‐rich olivine veinlets shows large chemical variations between and within grains. The Fe‐rich olivine veinlets also contain fine‐grained Fe³⁺‐bearing chromite, highly calcic plagioclase, merrillite, apatite, and troilite. Based on texture and mineral chemistry, we argue that the formation of Fe‐rich olivine was related to fluid deposition at relatively high temperatures. However, the source of Fe‐rich olivine in the veinlets remains unclear. Magnesium‐rich olivine veinlets were found in three diogenitic lithic clasts. In one of these, the Mg‐rich olivine veinlets only occur in one of the fine‐grained interstitial regions and extend into fractures within surrounding coarse‐grained orthopyroxene. Based on the texture of the interstitial materials, we suggest that the Mg‐rich olivine veinlets formed by shock‐induced localized melting and recrystallization. Pyroxene veinlets were only observed in one clast where they infill fractures within large plagioclase grains and are associated with fine‐grained pyroxene surrounding coarse‐grained pyroxene. The large chemical variations in pyroxene and the fracture‐filling texture indicate that the pyroxene veinlets might also have formed by shock‐induced localized melting and rapid crystallization. Our study demonstrates that silicate veinlets formed by a range of different surface processes on the surface of Vesta.  相似文献   

Seasonal variations of Aulacoseira granulata population abundance in the Pearl River Estuary     

Chao Wang  Xinhui LiZini Lai  Xichang TanShixun Pang  Wanling Yang 《Estuarine, Coastal and Shelf Science》2009

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造礁石珊瑚共生藻对富营养的响应研究     

雷新明  黄晖  王华接  李秀保  练健生 《海洋通报》2009,28(1)

研究了多孔鹿角珊瑚(Acropora millepora)及其共生藻在硝酸盐、铵盐、磷酸盐胁迫条件下的响应.结果表明,石珊瑚共生藻光合效率在各营养盐浓度下分别受到程度不同的抑制;表面共生藻密度及共生藻叶绿素 a 含量在硝酸盐、磷酸盐和铵盐与磷酸盐结合条件下都有所降低,但前者较后者的变化有所滞后;在铵盐作用下表面共生藻密度和共生藻叶绿素 a 含量均有所升高.以石珊瑚共生藻光合效率及叶绿素 a 含量作为指示珊瑚共生体系对胁迫的响应指标较为灵敏.  相似文献