An integrative study of larval organogenesis of American shad <Emphasis Type="Italic">Alosa sapidissima</Emphasis> in histological aspects     

高小强  洪磊  刘志峰  郭正龙  王耀辉  雷霁霖 《中国海洋湖沼学报》2016,34(1):136-152

We describe organogenesis at a histological level in American shad (Alosa sapidissima) larvae from 0 until 45 days after hatching (DAH). Larval development was divided into four stages based on the feeding mode, external morphological features, and structural changes in the organs: stage 1 (0–2 DAH), stage 2 (3–5 DAH), stage 3 (6–26 DAH) and stage 4 (27–45 DAH). At early stage 2 (3 DAH), American shad larvae developed the initial digestive and absorptive tissues, including the mouth and anal opening, buccopharyngeal cavity, oesophagus, incipient stomach, anterior and posterior intestine, differentiated hepatocytes, and exocrine pancreas. The digestive and absorptive capacity developed further in stages 2 to 3, at which time the pharyngeal teeth, taste buds, gut mucosa folds, differentiated stomach, and gastric glands could be observed. Four defined compartments were discernible in the heart at 4 DAH. From 3 to 13 DAH, the excretory systems started to develop, accompanied by urinary bladder opening, the appearance and development of primordial pronephros, and the proliferation and convolution of renal tubules. Primordial gills were detected at 2 DAH, the pseudobranch was visible at 6 DAH, and the filaments and lamellae proliferated rapidly during stage 3. The primordial swim bladder was first observed at 2 DAH and started to inflate at 9 DAH; from then on, it expanded constantly. The spleen was first observed at 8 DAH and the thymus was evident at 12 DAH. From stage 4 onwards, most organs essentially manifested an increase in size, number, and complexity of tissue structure.  相似文献   

Heavy metals in sediments and their bioaccumulation in <Emphasis Type="Italic">Phragmites australis</Emphasis> in the Anzali wetland of Iran     

Marjan Esmaeilzadeh  Abdolreza Karbassi  Faramarz Moattar 《中国海洋湖沼学报》2016,34(4):810-820

Accumulation of metals in both sediments and Phragmites australis organs was studied. Samples were collected from seven stations located in Anzali wetland, Iran. The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that concentration of the studied metals (except As and Cd) were higher in sediments than in P. australis organs. Metal accumulation was found to be significantly (P <0.05) higher in roots than in above-ground organs of P. australis. The bioaccumulation factor (BAF) and the transfer factor (TF) also verified the highest rate of metal accumulation in roots and their reduced mobility from roots to the above-ground organs. Pearson correlation coefficient showed significant relationships between metal concentrations in sediments and those in plant organs. It should be pointed out that sediment and plant samples exhibited higher metal concentrations in eastern and central parts than in western and southern parts of the wetland. The mean concentrations of all studied elements (except for Fe, V and Al) were higher in these sediment samples than in the Earth’s crust and shale. High accumulation of metals in P. australis organs (roots and shoots) is indicative of their high bioavailability in sediments of the wetland. The correlation between metal concentrations in sediments and in P. australis indicates that plant organs are good bioindicators of metal pollution in sediments of Anzali wetland.  相似文献   

Phylogenetic diversity of culturable bacteria in surface seawater from the Drake Passage,Antarctica     

李昭  邢孟欣  王伟  王丹  朱建成  孙谧 《中国海洋湖沼学报》2016,34(5):952-963

The Drake Passage is located between the Antarctic Peninsula and Tierra del Fuego in the south of South America. Surface seawater samples were collected at seven sites in the Drake Passage during the austral summer of 2012. The 16S rRNA sequences were analyzed from 187 isolated bacterial strains. Three phyla, 29 genera and 56 species were identified. The three phyla were Actinobacteria, Firmicutes and Proteobacteria; the Proteobacteria included α-Proteobacteria, β-Proteobacteria and γ-Proteobacteria. γ-Proteobacteria, Actinobacteria and Firmicutes were the dominant class or phyla in terms of quantity and species. Gram-positive bacteria (Actinobacteria and Firmicutes) accounted for 57.8% of all types identified. There were nine dominant genera, including Curtobacterium, Staphylococcus, and Halomonas, and 14 dominant species including Curtobacterium flaccumfaciens, Curtobacterium pusillum, and Staphylococcus sciuri. Of the strains identified, 87.2% were catalase positive or weakly positive.  相似文献   

川西坳陷东坡沙溪庙组气藏成藏演化模式   总被引：1，自引：0，他引：1  

徐敏  刘建  林小云  熊山  牛斌莉 《现代地质》2018,32(5):953

川西坳陷东坡气藏主力产层为沙溪庙组,其圈闭类型以构造-岩性圈闭为主,多为致密砂岩储层,但断层发育,有效改善了储层物性,断砂匹配样式与构造演化对油气成藏过程有重要影响。基于前人已有的认识,通过沙溪庙组气藏成藏动力演化、气水分布特征及生烃期次分析,结合构造演化、成藏幕次等研究,认为沙溪庙组天然气成藏受构造古隆起、断砂配置、储层物性、构造演化影响,形成了“构造控向、断砂控运、储层控藏、演化控调”的成藏演化模式,同中存异,高庙子地区古构造的控制作用更为明显,而中江地区岩性控制作用占主导。沙溪庙组气藏间歇性充注具“燕山期三幕成藏,喜山期调整改造”的成藏特征,多期构造演化和较强的储层非均质性影响了含气饱和度,导致沙溪庙组气藏分布、气藏产能差异大。  相似文献   

Source and yearly distribution of PAHs in the snow from the Hailuogou glacier of Mountain Gongga,China     

Chaoqi Yu  Meihan Li  Yinling Cao  Xian He  Hong Zhou  Tingting Zhang  Chongying Li 《中国地球化学学报》2018,37(3):456-464

Snow samples were collected over a 3-year period from 2012 to 2014 at the Hailuogou glacier of Mountain Gongga (Mt. Gongga) and analyzed for 16 priority polycyclic aromatic hydrocarbons (PAHs) using Gas Chromatography–Mass Spectrometry (GC–MS). The results show that total average levels of the 16 PAHs ranged from 452 to 290 ng·L^?1 with a possible declining trend from 2012 to 2014. Distances between the sampling sites and the emission sources were estimated at typically less than 500 km. The results suggest that the major source of PAHs was from coal combustion, while contributions from automobile exhaust played an important role in more recent years. This finding was in agreement with the characteristics of presence of local industry, residence, and recent development of tourism of the surrounding areas.  相似文献   

Enrichment characteristics and risk assessment of Hg in bird feathers from Caohai wetland in Guizhou Province,China     

Fengcheng Peng  Tianrong He  Zhenji Li  Mengyu Chen  Xiaoli Qian  Lingxia Zeng  Yiyuan Xu 《中国地球化学学报》2018,37(4):526-536

Based on the analysis of the enrichment characteristics of Hg and MeHg in bird feathers from Caohai National Nature Reserve in Guizhou, the risks of Hg pollution to the birds from Caohai wetland have been evaluated. The total Hg content of bird feathers ranges from 40 to 5058 ng/g with an average of 924 ng/g. The content of MeHg is significantly correlated with total Hg (r = 0.68, p < 0.01), and the content are among 0.75 and 113 ng/g. The total Hg content in the birds feathers is significantly dependent on their feeding habits, which is mainly in accordance with the following rule: carnivorous birds > omnivorous birds that are mainly carnivorous > omnivorous birds that are mainly herbivorous. There are also differences in the Hg enrichment ability in the different parts of bird feathers, and the total Hg and MeHg content in the wing feathers are significantly higher than that in the other parts of feathers. The bioaccumulation coefficients of aqueous Hg and MeHg by bird feathers are 0.9 × 10⁴–112.13 × 10⁴ (mean value is 20.47 × 10⁴) and 0.47 × 10⁴–70.4 × 10⁴ (mean value is 9.52 × 10⁴), respectively. Although the whole Hg level in Caohai bird feathers is not too high, the Hg content in some carnivorous birds exceeds over or approaches the abnormal threshold when birds are breeding (5 μg/g), which indicates that the birds in Caohai wetland are faced with some risks of ecological Hg pollution.  相似文献   

Oil geochemistry derived from the Qinjiatun–Qikeshu oilfields: insight from light hydrocarbons     

Jin Li  Min Zhang 《中国地球化学学报》2018,37(3):433-440

A suite of 27 oils from the Qinjiatun–Qikeshu oilfields in the Lishu Fault Depression of the Songliao Basin was analyzed using whole oil gas chromatography. In combination with the relative distribution of C₂₇, C₂₈, and C₂₉ regular steranes, detailed geochemical analyses of light hydrocarbons in oil samples revealed crude oils characterized by the dual input of lower aquatic organisms and higher terrestrial plants. Several light hydrocarbon indicators suggest that the liquid hydrocarbons have maturities equivalent to vitrinite reflectances of around 0.78%–0.93%. This is consistent with the maturity determination of steranes C₂₉ 20S/(20S + 20R) and C₂₉ ααβ/(ααα + αββ). Crude oils derived from the two distinct oilfields likely both have source rocks deposited in a lacustrine environment based on light hydrocarbon parameters and on higher molecular weight hydrocarbon parameters. The results show that light hydrocarbon data in crude oils can provide important information for understanding the geochemical characteristics of the Qinjiatun–Qikeshu oils during geologic evolution.  相似文献   

Distribution and geochemical significance of trace elements in shale rocks and their residual kerogens     

Jian-bing Xu  Bin Cheng  Qian Deng  Yun-gan Liang  Oluwabamise Lekan Faboya  Ze-wen Liao 《中国地球化学学报》2018,37(6):886-900

There is a dearth of information about the distribution of trace elements in kerogen from shale rocks despite several reports on trace element composition in many shale samples. In this study, trace elements in shale rocks and their residual kerogens were determined by inductively coupled plasma–mass spectrometry. The results from this study show redox-sensitive elements relatively concentrated in the kerogens as compared to the shales. This may be primarily due to the adsorption and complexation ability of kerogen, which enables enrichment in Ni, Co, Cu, and Zn. For the rare earth elements (REEs), distinct distribution characteristics were observed for shales dominated by terrigenous minerals and their kerogen counterparts. However, shales with less input of terrigenous minerals showed similar REE distribution patterns to their residual kerogen. It is speculated that the distribution patterns of the REEs in shales and kerogens may be source-related.  相似文献   

The morphological characteristics of gully systems and watersheds in Dry-Hot Valley,SW China     

Zhen Xu  Fachao Qin  Bin Zhang  Qingchun Deng  Hui Liu  Jie Jin  Liangtao Shi 《中国地球化学学报》2018,37(6):854-866

Gully systems and watersheds are geomorphic units with clear boundaries that are relatively independent of basin landscapes and play an important role in natural geography. In order to explore the morphological characteristics of gully systems and watersheds in the Dry-Hot Valley [South West (SW) China], gullies are interpreted from online Google images with high resolution and watersheds are extracted from digital elevation model at a scale of 1:50,000. The results show that: (1) There are 17,382 gullies (with a total area of 1141.66 km²) and 42 watersheds in the study area. (2) The average gully density of the study area (D) is 4.29 km/km², gully frequency (F) is 14.39 gullies/km², the branching ratio (B) is 5.13, the length ratio (L) is 3.12, and the coefficient of the main and tributary gullies (M) is 0.06. The degree of gully erosion is strong to extremely strong, the main development intensity of gully erosion ranges from intense to moderate, and the type of gully system is tributary. (3) The watershed areas (A) are between 0.39 and 96.43 km², the relief ratio (R) is from 0.10 to 0.19, the circularity ratio (C) is from 0.30 to 0.83, the texture ratio (T) is from 0.82 to 39.35, and the dominant geomorphological texture type is fine. (4) There is a quantitative relationship between F and D:F?=?0.624D² (R?=0.84) and T is closely related to D, F, M (R²?>?0.7). A, R and C are related to M (R²?>?0.5). The development of gully systems is the result of coupling effects between multiple factors. In this area, the degree of erosion and the condition of the main and tributary gullies can be controlled by the degree of topographic breakage in the watershed, which provides some theoretical basis for the evaluation of gully erosion by the latter. In addition, the scale, relief, and shape have a significant impact on the locations of the main and tributary gullies. For tributary gullies, attention should be paid to the interception and control of runoff and sediment in the small confluence branches in order to prevent gully expansion and head advance. These features can inform the development of targeted measures for the control of soil erosion.  相似文献   

A New Extension of Geological Work: To Grow Rice in the Desert     

HUANG Min  LIU Zhiqiang  FEI Hongcai  ZHOU Jian  ZHANG Yuxu  HAO Ziguo 《《地质学报》英文版》2018,92(3):1247-1248

正For thousands of years,a large number of peripheral rivers have been flowing into deserts,the water from which then will infiltrate underground or evaporate into the air.When desert sand engulfs and humans retreat,precious freshwater resources lie dormant all the year round,making almost no contribution to human progress.  相似文献