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471.
Lysosomal membrane stability, the content of neutral lipids and lipofuscin as cellular biomarkers were measured in the digestive gland of mussels, Mytilus galloprovincialis Lam., during a one year survey at selected sites along the coast of the northern Adriatic. The ability of mussels to survive in air as a general physiological response was tested at the same sites. Annual changes of sea temperature, salinity, O(2) saturation, pH and chlorophyll a concentration were measured and the effects of these environmental factors on the biomarkers selected for this study were determined. Survival of mussels after aerial exposure was significantly (p < 0.05) reduced in mussels collected from the contaminated harbors of Pula and Rijeka compared to clean control sites. Lysosomal membrane stability of mussels from urban and industrial areas was also lower indicating exposure to different environmental contaminants. At the same sites, the content of neutral lipids and lipofuscin in digestive cells was significantly higher compared to the reference sites, suggesting alterations in lipid metabolism and contaminant-induced peroxidation of cell membranes. The greatest influence of natural environmental factors was observed for the aerial survival of mussels and the neutral lipids and lipofuscin content in the digestive gland, indicating that the annual cycles of biomarker responses should be well understood for a correct interpretation of biomonitoring results. 相似文献
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474.
This field study aims to determine whether increased levels of organically enriched particulate matter released by net pen fish farms (Eilat, Red Sea) would affect the growth of nubbins taken from the branching coral Stylophora pistillata. We followed the survival and growth of 1322 nubbins pruned from five colonies that were transplanted at a depth of 6 m in the vicinity of the fish cages and in a reference site, in front of the Interuniversity Institute (IUI). Nubbins were attached on U-shaped PVC plates in three orientations (up, vertical and down positions). After 50 days, survival was high in both localities and no difference was recorded between the spatial orientations. At the fish farm, however, burial of the nubbin's lateral growths and partial coverage of nubbins by settled particulate matter resulted in significant reduction of the lateral growth rates of nubbins settled in the up position as compared to the reference site. On the other hand, faster growth rates were recorded in the vertical set of nubbins at the fish farm when compared with the IUI site. These results strengthen the conclusion that physical effects, rather than nutrient enrichment, may constitute the main cause of stress for minute coral fragments (resembling coral recruits) growing near the vicinity of a fish farm. 相似文献
475.
国家历史地理信息系统 总被引:1,自引:0,他引:1
GIS可以有效地获取、存储、分析并显示空间数据及与其相关的空间可寻址的数据集。大量的空间数据都与人口统计有关,包括人口普查局的TIGER文件。TIGER文件指可进行空间分析和制图的地理编码的街道和调查单元的文件。现在,研究者们开始尝试使用人口普查的地 相似文献
476.
图11和图12分别给出了对地表位移未作约束和有约束时由实际数据分别反演和联合反演得到的滑动分布。它们有共同的特征:(1)在模型西部的深处缺少滑动;(2)在模型的中部,从格尔居克以西约10km到萨潘贾湖的东邻区,存在高滑动值(4~8m);(3)在最东段滑动显著。没有地表位 相似文献
477.
2002年11月3日,阿拉斯加中部发生了一次Mw7.9级的地震。该地震使部分苏西特纳冰川断层、迪纳利断层及托茨春达断层发生破裂。反演GPS测量的位移场表明,该事件以沿迪纳利断层复杂的右旋走滑破裂占优势。最靠近震中的GPS测点显示出苏西特纳冰川断层有逆冲运动的影响。优选的Mw7.9级地震同震滑动模型表明,在破裂的西段滑动相对较小,而在震中以东约60km至在迪纳利断层和托茨春达断层的交汇处滑动相对较大。我们发现大多数浅层滑动从地表至深15km,但反演却表明在震中以东110km有一大的深部滑移层。我们的模型预示地表滑动与地表地质观测非常一致,模型分辨率也非常好。 相似文献
478.
Xi HUANG Jisen DAI Robert B. Finkelman 《中国地球化学学报》2006,25(B08):216-217
Backgrounds: Coal is and will remain a major energy resource worldwide with P.R. China and the U.S. the leading producers. It has long been known that coal mining causes health problems such as coal workers' pneumoconiosis (CWP) and chronic obstructive pulmonary disease (e.g., emphysema). Yet, there are no accurate methods for predicting their occurrence. The goals of the present study are to determine whether bioavailable iron (BAI) is the active component in coal dust-induced lung diseases and to develop a model using BAI for the prediction of coal's pneumoconiotic potency. Methods: Thirty coal samples from Utah (UT), West Virginia (WV) and Pennsylvania (PA) coalmine regions with a low, moderate, and high prevalence of CWP, respectively, 相似文献
479.
Wei CHEN Mason B. Tomson 《中国地球化学学报》2006,25(B08):262-263
Adsorption and desorption are critical processes controlling the fate and transport of organic contaminants in natural environment. Numerous studies have shown that only a fraction of contaminants in soil or sediment can readily be desorbed to the aqueous phase, while desorption of the remaining fraction is very difficult and does not follow the conventional desorption models-a phenomenon typically referred to as "resistant desorption" or "sequestration" and is argued by many as the cause of reduced availability of contaminants in soil and sediment. While this reduced availability often reduces the effectiveness of soil and sediment remediation, the same effect can also greatly reduce risk of contaminated soil and sediment. The authors have conducted extensive lab and field studies to characterize the unique properties of sequestration of organic contaminants and to understand the mechanism(s) controlling sequestration. Thus far, over 50 different contaminant-soil/sediment combinations have been evaluated, using contaminants of varied physical-chemical properties (e.g., chlorinated benzenes, PAHs, PCBs, DDT, atrazine, hexachlorocyclohexane isomers, etc.). Several unique characteristics of sequestration have been observed, and the most striking one is that despite the significant differences in chemical and soil properties, desorption of sequestered contaminants for all the contaminant-soil/sediment combinations exhibited very similar KOC (organic-carbon normalized partition coefficient) and very similar desorption kinetics. 相似文献
480.
Nurlidia Mansor Ian D. Pulford Angus B. MacKenzie 《中国地球化学学报》2006,25(B08):23-23
Tyndrum was an industrial mining area from 1741 until the 1920s where the main ores extracted were lead sulphide (galena) and zinc sulphide (sphalarite). Situated in central Scotland, the now deserted site is identified as a highly polluted, barren area where the original waste residues from the mine, an ore processing and a smelting site are clearly evident. Previous studies have suggested that high levels of lead and zinc contaminants are still dispersed from this former mine site, both atmospherically and through fluvial transport. For example, high concentrations of Pb, identified by its isotopic signature as originating in Tyndrum, have been found in sediments in Loch Tay, 25 km east of this area. This paper presents the results of a study of the occurrence and magnitude of airborne contamination by dispersion from the former mine site using measurements of metal concentrations in tree bark. These naturally occurring ‘bio monitors', which accumulate airborne materials including heavy metals, have become an effective alternative to the more costly air-filter system, which is restricted in scope and coverage. Bark samples were acquired from Scots pine (Pinus sylvestris) trees, which are abundant around the derelict mine site. Suitable locations were chosen to investigate atmospheric transport and deposition of contaminants within the area. 相似文献