Organic carbon and nitrogen stable isotopes in the intertidal sediments from the Yangtze Estuary, China   总被引：2，自引：0，他引：2  

Liu M  Hou LJ  Xu SY  Ou DN  Yang Y  Yu J  Wang Q 《Marine pollution bulletin》2006,52(12):1625-1633

The natural isotopic compositions and C/N elemental ratios of sedimentary organic matter were determined in the intertidal flat of the Yangtze Estuary. The results showed that the ratios of carbon and nitrogen stable isotopes were respectively −29.8‰ to − 26.0‰ and 1.6‰–5.5‰ in the flood season (July), while they were −27.3‰ to − 25.6‰ and 1.7‰–7.8‰ in the dry season (February), respectively. The δ¹³C signatures were remarkably higher in July than in February, and gradually increased from the freshwater areas to the brackish areas. In contrast, there were relatively complex seasonal and spatial changes in stable nitrogen isotopes. It was also reflected that δ¹⁵N and C/N compositions had been obviously modified by organic matter diagenesis and biological processing, and could not be used to trace the sources of organic matter at the study area. In addition, it was considered that the mixing inputs of terrigenous and marine materials generally dominated sedimentary organic matter in the intertidal flat. The contribution of terrigenous inputs to sedimentary organic matter was roughly estimated according to the mixing balance model of stable carbon isotopes.  相似文献   

Changes in biodiversity of the extremely polluted Golden Horn Estuary following the improvements in water quality     

Yüksek A  Okuş E  Yilmaz IN  Aslan-Yilmaz A  Taş S 《Marine pollution bulletin》2006,52(10):1209-1218

Long-term biological data supported by physicochemical parameters were evaluated to investigate the biodiversity of the Golden Horn Estuary from the past to the present. Limited observations dating back to 60 years ago indicated the existence of a diverse community in this small estuary. Unfortunately, in parallel with the increase in unplanned settlements and industry around the Golden Horn, pollution stress increased since the 1960s. Preliminary studies in the 1990s indicated survival of only a couple of pollution-resistant species, in the relatively cleaner lower estuary. Following the intensification of rehabilitation studies in 1998 and particularly after the opening of the floating bridge at the mid estuary; a remarkable day-by-day recovery in marine life has begun with the improving water quality. Nutrient concentrations decreased markedly; while water clarity significantly increased. Fecal coliform values decreased 10(3) fold. Phytoplankton composition changed and dense blooms of eukaryotic phytoplankters frequently occurred. Hydrogen sulfide almost completely disappeared even during the warmest periods of the year and dissolved oxygen concentrations increased. All results clearly depicted that the Golden Horn ecosystem shifted to eutrophic conditions from an anoxic environment. SCUBA dives in 2002, documented the level of diversification of life in the Golden Horn. All appropriate substratums were intensely covered by macrobenthic forms until the Halic Bridge and filter feeders dominated the plankton-rich ecosystem. Achieving the diversity of 1940s is not possible since the Black and Marmara seas, influencing water quality of the Golden Horn, are also suffering from anthropogenic impacts and are far less diverse than their rich diversity in 1940s. However, the Golden Horn is a good example that even the most polluted ecosystems can recover when appropriate measures are taken.  相似文献   

Microbial responses using denaturing gradient gel electrophoresis to oil and chemical dispersant in enclosed ecosystems     

Yoshida A  Nomura H  Toyoda K  Nishino T  Seo Y  Yamada M  Nishimura M  Wada M  Okamoto K  Shibata A  Takada H  Kogure K  Ohwada K 《Marine pollution bulletin》2006,52(1):89-95

Microbial responses to the addition of oil with or without a chemical dispersant were examined in mesocosm and microcosm experiments by using denaturing gradient gel electrophoresis of bacterial ribosomal DNA and direct cell counting. When a water-soluble fraction of oil was added to seawater, increases in cell density were observed in the first 24h, followed by a decrease in abundance and a change in bacterial species composition. After addition of an oil-dispersant mixture, increases in cell density and changes in community structure coincided, and the amount of bacteria remained high. These phenomena also occurred in response to addition of only dispersant. Our results suggest that the chemical dispersant may be used as a nutrient source by some bacterial groups and may directly or indirectly prevent the growth of other bacterial groups.  相似文献   

青藏高原东南缘构造地貌、活动构造和下地壳流动假说   总被引：6，自引：0，他引：6       下载免费PDF全文

刘静  曾令森  丁林  Tapponnier P  Gaudemer Y  文力  谢克家 《地质科学》2009,44(4):1227-1255

利用高精度的SRTM 数字高程模型（DEM）,定量勾画出青藏高原东南缘大尺度地形地貌的特征。分析表明,高原东南缘地貌特征为“负地形”,即海拔高程与地形坡度,与地形起伏度之间均为负相关关系,与高原中部的“正地形”--海拔高程或地形坡度与地形起伏度之间呈正相关关系,形成鲜明对比。但是,在高原东南缘,在河谷之间保留有高海拔、低起伏的残留面。这些残留面与高原内部的平坦面具相似的渐变地貌特征,从腹地的正地形逐渐变为川西的高海拔平坦面与深切河谷相间的负地形。虽然随着河流下切深度往南逐渐增加,残留面虽越来越少,但仍然可以识别,最终终止在雅砻江逆冲断裂带附近,该断裂带以南地区没有明显负地形特征。北东向展布的雅砻江逆冲断裂带对应着50～200 km宽的地形相对陡变带。综合区域新构造和构造地貌研究的最新成果表明： 1）雅砻江逆冲断裂带可能代表着现今正经受侵蚀改造和弱化的高原老边界,该边界以北和以南地区抬升历史不同; 2）三江地区的峰值抬升期已过,目前以侵蚀为主。虽然不能排除与河流侵蚀对应的均衡反弹抬升作用,但具有真正意义的地壳增厚型的构造抬升较弱。国际上流行的高原东缘下地壳流动模式的依据之一是从高原内外流分界线到南中国海,存在一个区域上延伸数千公里的抬升前低海拔“类夷平面”的残留面。地貌特征,构造和地质综合分析都表明高原东缘不存在这样的类夷平面,不支持解释高原东缘地形演化和相应构造变形的下地壳流动模式。  相似文献   

氯化钙对水土环境污染特征分析          下载免费PDF全文

申中华  王梅  雷耀东  张世杰  李成刚  王立艳 《山东国土资源》2020,36(8):54-60

某生产CaCl2化工厂因环境问题被停止生产,厂区周边土壤和地下水受到不同程度的污染。为掌握污染土壤中污染因子的含量和地下水受污染情况,布置了土壤采样点和地下水监测点,利用厂区周边已有机民井进行水样采集,通过室内检测、分析研究等工作,得出在厂区周边土壤60~300 cm深度范围内存在Ca^2+,Cl^-富集,鉴于土壤的天然吸附和自净能力,目前条件下,厂区及周边地下水污染状况受影响较小。通过抽水试验、渗水试验和弥散试验,圈定了污染物的影响范围,查明了污染物的影响程度,并在此基础上进行了污染物影响变化情况的预测分析,为后续区域污染地块的风险评估和修复治理工作提供了数据支持。  相似文献   

A Reviewofthe Stratigraphy, Structure and Geological History of the Szechuan red basin and the Occurrence of Natural Gas, Oil, Brines and Rock Salt Contained Therein with Special Discussions of their Origin and Future Prospects     

C.Y.HSIEH 《地质学报》1947

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On the Age of the Hsiwan Coal Series     

C.Y.HSIEH 《地质学报》1940,20(1)

The geology of the Hsiwan coal field has been studied by Dr. Yoh of theGeological Survey of Kwangtung and Kwangsi and Messrs. Meng and Chang ofthe Geological Institute of the Academia Sinica. All these authors assigned aLower Carboniferous age to the coal-bearing series. Their grounds are probably  相似文献   

On the Possible Oil Fields in Szechuan as Indicated by Isocarb Lines     

Y.HCHIN  V.C.IUAN 《地质学报》1940,(Z1)

Ⅰ. INTRODUCTION From the considerations of the scattered oil occurrences and suitablegeological structures, the Red Basin of Szechuan has long been regarded as apromising country for oil prospecting. In the last decade much attention hasbeen paid by geologists and engineers to the search for oil resources in certain  相似文献   

An Outline of the Geological Structure of the Western Hills of Peiping     

C.Y.HSIEH 《地质学报》1937,(Z1)

As a pioneer worker in almost every phase of the Chinese geology,the late Dr. V. K. Ting was also a pioneer and enthusiastic worker inthe geology of the Western Hills. It was due to his noble effort andsupervision that the first systematic investigation of 1916 was carried out  相似文献   

OBITUARY NOTE ON MR.S.W.WANG     

C.Y.HSIEH 《地质学报》1936,15(2):269-270

The untimely death of Mr.S.W.Wang on Feb.10th 1936 iscertainly a serious loss to the Chinese geology.Although his name is notso well known as others in the geological circle,Mr.Wang has indeedmade remarkable contribution to the study of Chinese crystals and  相似文献