δ15N variation in Ulva lactuca as a proxy for anthropogenic nitrogen inputs in coastal areas of Gulf of Gaeta (Mediterranean Sea)     

《Marine pollution bulletin》2014,85(1-2):76-82

We tested the capacity of Ulva lactuca to mark N sources across large marine areas by measuring variation in its δ¹⁵N at several sites in the Gulf of Gaeta. Comparisons were made with the macroalga Cystoseira amentacea. Variation of δ¹⁵N values was assessed also in the coastal waters off the Circeo Natural Park, where U. lactuca and C. amentacea were harvested, as these waters are barely influenced by human activities and were used as reference site. A small fragment from each frond was preserved before deployment in order to characterize the initial isotopic values. After 48 h of submersion, U. lactuca was more responsive than C. amentacea to environmental variation and δ¹⁵N enrichment in the Gulf of Gaeta was observed. The spatial distribution of δ¹⁵N enrichment indicated that different macro-areas in the Gulf were affected by N inputs from different origins. Comparison of the δ¹⁵N values of fragments taken from the same transplanted frond avoided bias arising from natural isotopic variability.  相似文献   

Enzymatic methods for the determination of pollution in seawater using salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius     

《Marine pollution bulletin》2014,80(1-2):188-195

A new salt resistant alkaline phosphatase from eggs of the sea urchin Strongylocentrotus intermedius (StAP) has been shown to have a unique property to hydrolyze substrate in seawater without loss of enzymatic activity. The enzyme has pH optimum at 8.0–8.5. Model experiments showed various concentrations of copper, zinc, cadmium and lead added to seawater or a standard buffer mixture to inhibit completely the enzyme activity at the concentrations of 15–150 μg/l. StAP sensitivity to the presence in seawater of metals, pesticides, detergents and oil products appears to be considerably less. Samples of seawater taken from aquatic areas of the Troitsy Bay of the Peter the Great Bay, Japan Sea have been shown to inhibit the enzyme activity; the same was shown for the samples of fresh waters. The phosphatase inhibition assay developed proved to be highly sensitive, technically easy-to use allowing to test a great number of samples.  相似文献   

Maternal-to-fetal transfer and concentration profiles of PCB congeners for Steller sea lions (Eumetopias jubatus) from Hokkaido,Japan     

《Marine pollution bulletin》2014,78(1-2):165-172

The concentrations of PCB congeners in the blubber and liver of mother Steller sea lions (Eumetopias jubatus; SSLs) and their fetuses from the coast of Hokkaido, Japan in 2008, 2010 and 2012 were analyzed by HRGC–HRMS, in order to elucidate PCB congener profiles and maternal-to-fetal transfer of PCBs in SSLs. ΣPCBs in the fetuses were 1400 ± 660 (the mean ± SD) ng/g-fat in the blubber and 570 ± 320 ng/g-fat in the liver, respectively. There was a concern that SSLs had been contaminated by PCBs during the fetal period. The concentrations of the major congeners in the blubber and liver were a correlation between the fetus and mother (blubber: r = 0.9934, liver: r = 0.9160; P ≦ 0.05). The results indicated that PCBs in the fetuses came from the mothers. #177 and #199 showed no correlations between the fetus and the mother in the blubber and liver. This indicated a selective capture by some natural protector such as the placenta.  相似文献   

Granitic coastal geomorphology: applying integrated terrestrial and bathymetric LiDAR with multibeam sonar to examine coastal landscape evolution          下载免费PDF全文

David M. Kennedy  Daniel Ierodiaconou  Alexandre Schimel 《地球表面变化过程与地形》2014,39(12):1663-1674

Coasts composed of resistant lithologies such as granite are generally highly resistant to erosion. They tend to evolve over multiple sea level cycles with highstands acting to remove subaerially weathered material. This often results in a landscape dominated by plunging cliffs with shore platforms rarely occurring. The long‐term evolution of these landforms means that throughout the Quaternary these coasts have been variably exposed to different sea level elevations which means erosion may have been concentrated at different elevations from today. Investigations of the submarine landscape of granitic coasts have however been hindered by an inability to accurately image the nearshore morphology. Only with the advent of multibeam sonar and aerial laser surveying can topographic data now be seamlessly collected from above and below sea level. This study tests the utility of these techniques and finds that very accurate measurements can be made of the nearshore thereby allowing researchers to study the submarine profile with the same accuracy as the subaerial profile. From a combination of terrestrial and marine LiDAR data with multibeam sonar data, it is found that the morphology of granite domes is virtually unaffected by erosion at sea level. It appears that evolution of these landscapes on the coast is a very slow process with modern sea level acting only to remove subaerially weathered debris. The size and orientation of the joints determines the erosional potential of the granite. Where joints are densely spaced (<2 m apart) or the bedrock is highly weathered can semi‐horizontal surfaces form. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

浅海孔底锤击绳索取芯钻探工艺浅析     

靳程  贺超  孙水文 《防灾减灾学报》2014,(2):71-74

主要介绍了浅海海域锆钛砂矿勘查中采用孔底锤击绳索取芯钻探工艺的原理、注意事项并简单介绍工程实例。经实践证明该工艺具有较好的使用价值,可以推广到工程钻探中。  相似文献   

高分辨率层序地层分析中基准面变化的讨论   总被引：14，自引：2，他引：12  

李江涛  李增学  郭建斌  余继峰 《沉积学报》2005,23(2):297-302

基准面有三个不同的概念,即侵蚀基准面、沉积基准面和地层基准面。目前对于基准面的解释和应用存在争论,在应用中尤其比较模糊。在对高分辨率层序地层学中地层基准面的解释进行分析及基础上,对其在解释以海相沉积环境为主的部分提出了质疑并就可容空间与地层基准面的关系问题进行了讨论。可容空间是层序地层学关键概念,基准面也是层序地层学很重要的概念,两者对于解释层序形成机制是非常重要的。侵蚀基准面、沉积基准面、地层基准面都是势能面,都是动力学界面,都是变化的,只是分析的基准不同、形成的机制不同。为了深入地揭示这三种基准面的特征,还应该考虑基准面的定量研究问题。  相似文献   

冬季北极海冰运动主模态的构成及其与海平面气压变化的关系   总被引：2，自引：0，他引：2  

武炳义 《大气科学》2005,29(5):747-760

利用国际北极浮冰运动观测资料（IABP）（1979-1998）以及NCEP／NCAR月平均海平面气压再分析资料（1960-2002）,通过求解海冰运动异常的复斜方差矩阵,研究了冬季北极海冰运动主模态构成及其与海平面气压变化的关系。冬季海冰运动主模态是由两个海冰运动优势模态的一个线性组合构成,与这两个运动优势模态有直接关系的海平面气压变化主要发生在北极海盆及其边缘海区。尽管北极涛动（北大西洋涛动）通过影响海平面气压进而影响北极海冰运动,但是,北极涛动（北大西洋涛动）并不是决定海冰运动主模态的关键性因素。  相似文献   

地震周期的数值估计   总被引：2，自引：0，他引：2  

杨冬红  杨学祥 《国际地震动态》2005,(12):37-43

模拟计算表明,地震有多种成因,多种因素的周期复合掩盖了地震的周期性。环太平洋地震带受板块运动、潮汐波动、厄尔尼诺、拉尼娜、海平面变化、剥蚀沉积、太平洋十年涛动等诸多因素影响,地震活动最为强烈,8．5级以上强震有明显的准60年和1800年潮汐波动周期。  相似文献   

Climate-Induced Variability of Sea Level in Stockholm： Influence of Air Temperature and Atmospheric Circulation     

Deliang CHEN  Anders OMSTEDT 《大气科学进展》2005,22(5):655-664

This study is focused on climate-induced variation of sea level in Stockholm during 1873-1995. After the effect of the land uplift, is removed, the residual is characterized and related to large-scale temperature and atmospheric circulation. The residual shows an overall upward trend, although this result depends on the uplift rate used. However, the seasonal distribution of the trend is uneven. There are even two months （June and August） that show a negative trend. The significant trend in August may be linked to fresh water input that is controlled by precipitation. The influence of the atmospheric conditions on the sea level is mainly manifested through zonal winds, vorticity and temperature. While the wind is important in the period January-May, the vorticity plays a main role during June and December. A successful linear multiple-regression model linking the climatic variables （zonal winds, vorticity and mean air temperature during the previous two months） and the sea level is established for each month. An independent verification of the model shows that it has considerable skill in simulating the variability.  相似文献   

北极海冰的气候变化与20世纪90年代的突变   总被引：5，自引：0，他引：5  

方之芳张丽  程彦杰 《干旱气象》2005,23(3):1-11

应用英国Had ley气候研究中心1968~2000年的1°×1°的北半球逐月海冰密集度资料,使用EOF分解等统计方法,探讨北极海冰的气候变化趋势、海冰的突变、海冰的季节持续性和各季的特色。结果表明:(1)自1968年以来,北极海冰的减小是北半球海冰变化的总趋势;海冰的趋势变化在海冰的年际总变化中占有相当重要的地位,可达50%左右。冬春季主要减少区域在格陵兰海、巴伦支海和白令海;夏秋季海冰减少是唯一趋势,中心在北冰洋边缘的喀拉海、拉普捷夫海、东西伯利亚海、楚科奇海、波弗特海。(2)20世纪80年代中后期北极海冰已出现减小趋势,在20世纪90年代,海冰又出现范围和面积的突然减少,中心在格陵兰海和巴伦支海;即海冰减少是加速的,其变化程度已远远超过一般的自然变化。(3)海冰有很好的季节持续性,有很强的隔季相关,也有较好的隔年相关;各季节海冰分布型之间有很好的联系,表现为海冰分布型的总体变化趋势是一致的,在海冰的减少中也体现了分布型的特征。  相似文献