北美洲东南近海布莱克海岭中气体水合物赋存沉积区域内自生碳酸盐矿物的分带特点     

N．M．Rodriguez陆红锋  廖志良 《海洋地质》2004,(4):44-64

自生碳酸盐矿物的分布特点，是体现孔隙水地球化学特征的一个侧面。在布莱克海岭气体水合物赋存的沉积区域里(ODP994#、995#、997#)就利用这点来评价成岩作用。碳酸盐矿物的分布特点揭示了三个独特的成岩分带：(1)在上部20mbsf (bsf：below seafloor，海底以下深度)处的碳酸盐矿物主要是生物成因的，没有显示成岩作用的存在。这个区域的方解石FOC和8180值(PDB)反映了海相碳酸盐的特点，是与海水平衡的条件下沉淀形成的；(2)在20mbsf和100mbsf深度，方解石的FOC值明显呈现负数(低至-7．0‰)，自生白云石较普遍可见(2—40wt％)，δ^13C值在3．6‰～13．7‰之间；(3)在，100mbsf以下，白云石从含量丰富减低至微量分布，而分散状的菱铁矿成为主要出现的矿物。菱铁矿的δ^1C和δ^18O值分别在5．0‰～10．9‰、2．9‰～7．6‰之间变化。把溶解无机碳(DIC)的δ^1C剖面分布特点和孔隙水的浓集梯度趋势与自生碳酸盐矿物的δ^13C和δ^18O值对比，我们发现，自生碳酸盐矿物在一个独特的深度区域里形成，呈带状分布。在20mbsf深度及以下，无机碳的δ^13C DIC出现最小负值(≤-38‰)、方解石白云石出现δ^13C负值，这种现象的出现是伴随着孔隙水碱度的增加、硫酸盐的亏损和孔隙间Ca^ 2 、Mg^ 2 离子的减少一起发生的，这表明自生方解石和自生白云石的形成是在硫酸盐还原带的底部开始(21mbsf左右)而在100mbsf附近深处大量出现。菱铁矿的形成很显然是在120～450mbsf之间发生，这个区间在气体水合物赋存的沉积物区域内和上部(赋存区域200—450mbsf)。菱铁矿的δ^13C和δ^18O值从它们出现的薄层一直到沉积物底部都几乎一致。然而，现在孔隙水中的δ^13C DIC仅仅与120～450mbsf间的菱铁矿的δ^13C值相似。此外，从菱铁矿中计算出来的与之平衡的δ^18O值与120～450mbsf区段处菱铁矿的δ^18O测量值很好地匹配起来。该区段以高碱度(40-120mm)、低Ca^ 2 、Mg^ 2 浓集度为特征，这符合菱铁矿的形成条件。  相似文献   

一个湍能封闭模型对风暴潮海底底应力的应用研究     

魏更生  汪景庸 《中国海洋大学学报(自然科学版)》1994,(2)

将一个三维湍能封闭模型应用于开阔海区的风暴潮，通过数值计算探讨了Ｔａｙｌｏｒ底摩擦二次率的拖曳系数随空间的分布及拖曳系数与水深、海底粗糙度、风向和风速等因素的关系。本文对底摩擦二次率的可靠性做了评价。  相似文献   

Bacterial killing by Mytilus hemocyte monolayers as a model for investigating the signaling pathways involved in mussel immune defence     

Canesi L  Scarpato A  Betti M  Ciacci C  Pruzzo C  Gallo G 《Marine environmental research》2002,54(3-5):547-551

The signaling pathways involved in mussel immune defence were investigated utilizing a model of killing of Escherichia coli by Mytilus galloprovincialis hemocytes in a co-culture setting. In particular, the role played by different mitogen activated protein kinases (MAPKs) and by the production of eicosanoids were investigated utilising specific cell permeant, pharmacological enzyme inhibitors. Hemocyte pretreatment with the p38 MAPK inhibitor SB203580 significantly reduced bacterial killing, whereas PD98059 (an inhibitor of ERK--extracellularly regulated kinase--MAPK activation) had no significant effect. Wortmannin also inhibited bacterial killing, indicating a crucial role for PI3-kinase activation in the immune response. Killing of E. coli was also reduced by inhibitors of both PLA2 and cyclooxygenase activities, indicating that eicosanoid production is involved in mediating the response to bacterial challenge. The results demonstrate that bacterial killing by mussel hemocytes is particularly sensitive to inhibitors of the key steps involved in the transduction of bacterial signals into the host cell. Moreover, these data indicate that the hemocyte bactericidal activity can be suitably utilized not only for identifying the signaling pathways involved in the response to bacterial infection, but also as a potential investigative-toxicology model to test drugs and contaminants for their effect on the overall mussel immune defence.  相似文献   

大洋锰结核中矿物对过渡金属分布的控制     

GuobinLei李琳  魏合龙 《海洋地质前沿》1995,(9):11-12

大洋锰结核中矿物对过渡金属分布的控制ＧｕｏｂｉｎＬｅｉ等关于大洋锰结核、结壳中Ｃｏ、Ｎｉ和Ｃｕ在１０Ａ锰酸盐、水羟锰矿及铁的氧氢氧化物（简称为铁相）之间分布的讨论主要是在全样分析数据的基础上进行的。我们通过分层取样，对锰结核不同的微层同时进行了化学及...  相似文献   

Histopathological biomarkers in estuarine fish species for the assessment of biological effects of contaminants   总被引：1，自引：0，他引：1  

Stentiford GD  Longshaw M  Lyons BP  Jones G  Green M  Feist SW 《Marine environmental research》2003,55(2):137-159

The increasing emphasis on the assessment and monitoring of estuarine ecosystems has highlighted the need to deploy appropriate biological indices for these locations. Fish diseases and histopathology, with a broad range of causes, are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of historical exposure. This study reports on the histopathological alterations observed in selected organs and tissues of three species of estuarine fish (Platichthys flesus, Pomatoschistus minutus and Zoarces viviparus), captured from four British estuaries (the Tyne, Tees, Mersey and Alde), differently impacted by contaminants, including PAHs. A biannual sampling regime was used to identify the important seasonal variations that occur in terms of the observed biological effects. Inflammatory lesions and hepatocellular fibrillar inclusions attained their highest prevalence in P. flesus captured from the Tyne, Tees and Mersey. The presence of pre-neoplastic and neoplastic toxicopathic lesions was highest in P. flesus captured from these sites, when compared to fish from the Aide reference site. In particular, the prevalence of hepatic foci of cellular alteration (up to 43.3%) and hepatocellular adenoma (up to 10%) were highest in P. flesus captured from the Mersey estuary. Intersex (ovotestis) was only recorded in male P.flesus captured from the Mersey estuary (up to 8.3%) and from male Z. viviparous captured from the Tyne estuary (25%). Pathologies associated with the gill and the kidney were also most prevalent in fish captured from the Tyne, Tees and Mersey estuaries. This study has successfully applied histopathology to an estuarine monitoring program, both for the recording of toxicopathic lesions in the liver and other organs, and for the detection of the endpoint of endocrine disruption, intersex. As such, it provides a powerful integrative tool for the assessment of biological effects of contaminants in these environments.  相似文献   

五种植物提取液的抗鱼病菌和抗鱼病毒效应(英文)   总被引：1，自引：0，他引：1  

童裳亮  F.M.Hetrick  B.S.Roberson  A.Baya 《中国海洋大学学报(自然科学版)》1990,(2)

本文旨在探索用廉价的野生植物防治鱼病。所用的植物有牛繁缕(Stellaria aqu-atica),双花凤仙(Impatiens biflora),夜来香(Oenothera biennis),艾草(Artem-isia vulgaris)和忍冬(Lonicera japonica)。用作试验的鱼病菌共13种(18个菌株),分属于气单孢菌属、假单孢菌属、爱德华氏菌属、耶尔森氏菌属、弧菌属。所用的鱼病毒为传染性胰脏坏死病毒IPNV,传染性造血组织坏死病毒IHNV。上述病原微生物均获自美国马里兰大学微生物系。实验结果表明,五种植物提取液均有不同程度的抗鱼病菌作用,其中以牛繁缕的抗菌谱最广,作用力最强。忍冬、艾草、牛繁缕有抗鱼病毒作用。其中以忍冬的效果最好,它能抑制IPNV和IHNV。而艾草和牛繁缕只能抑制IHNV。  相似文献   

Measuring lysosomal stability as an effective tool for marine coastal environmental monitoring     

Castro M  Santos MM  Monteiro NM  Vieira N 《Marine environmental research》2004,58(2-5):741-745

The use of lysosomal stability in the mussel, Mytilus galloprovincialis, as a potential biomarker of environmental contamination has been evaluated along the Portuguese coast. To this end, the neutral red retention (NRR) time was measured in mussel haemocytes gathered from nine different locations reflecting different degrees of anthropogenic contamination. Mussels collected in the vicinity of industrial and urban areas showed the lowest lysosomal stability. Additionally, no significant seasonal variability (winter-spring/summer) for NRR time was observed. In order to further support the usefulness of this method as an integrated tool for monitoring marine coastal environments, we compared the levels of xenobiotics in mussel tissues with the obtained NRR values. The results highlighted a consistent pattern, with the lowest lysosomal stability intimately correlated with the higher contaminant concentrations. In summary, this integrated approach further demonstrated that the NRR assay can provide useful and objective indications of the real health status of organisms subjected to different stress agents, being a valid option for environmental monitoring.  相似文献   

海河口演变特性分析   总被引：4，自引：0，他引：4  

张相峰  魏玉琴 《海洋通报》1995,14(1):37-45

总结了海河口的历史变化过程，通过实测资料分析了海河口建闸后的淤只情况、目前的淤积形态及其主要原因，认为河口建闸３０ａ来，在径流量逐渐减小的条件下，潮汐水流是塑造闸下淤积形态的主要动力。  相似文献   

前陆盆地向稳定状态的演化：来自台湾西部前陆盆地的证据   总被引：1，自引：0，他引：1  

Covey  M. 项光 《海洋地质译丛》1989,(1):36-43

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碳同位素质谱法探讨现代海洋有机沉积物来源     

朱桂海  Jame M.Brooks 《海洋学研究》1986,(2)

本文用NUCLIDE RMS 6-60质谱仪测定了长江口及邻近海区(北纬30°06′至31°15′,东经122°30′至124°30′)表层沉积物中有机碳稳定同位素组成(δ~(13)C为-23.6×10~(-3)—-21.3×10~(-3))、有机碳含量(0.4—0.1％),溶剂可提取有机物浓度及有机C/N比值。结果表明,从有机地球化学角度解释并证实了其他地学家在该区域的研完成果,即东海陆架泥质沉积物主要由陆源悬浮物和海洋浮游生物体混合组成,长江入海物质随着远离长江口而递减,大部分陆源悬浮物向东南运移,并沉积在东经123°以西的长江口区。  相似文献