Occurrence and Activity of Lipolytic Bacterioneuston and Bacterioplankton in the Estuarine Lake Gardno     

Z. J. Mudryk  P. Skrczewski 《Estuarine, Coastal and Shelf Science》2000,51(6):763

The number and lipolytic activity of neustonic and planktonic bacteria inhabiting estuarine Lake Gardno were determined. Lipolytic bacteria were very numerous in investigated layers of water, accounting for 10–88% of the total number of culturable heterotrophic bacteria. Significant differences were found in the decomposition of individual lipid substrates by bacteria. The highest percentage of neustonic and planktonic strains were able to hydrolyse tributyrin and Tween 85. The least numerous bacteria group was microflora hydrolysing Tween 20 and Tween 40. The activity of lipases synthesized by bacteria from the subsurface layer was higher than that of lipases produced by bacteria isolated from the surface layers. A significant effect of salinity on the activity of lipases has been shown.  相似文献   

Columbia Bay, Alaska: an ‘upside down’ estuary     

Roy A. Walters  E. G. Josberger  C. L. Driedger 《Estuarine, Coastal and Shelf Science》1988,26(6)

Circulation and water properties within Columbia Bay, Alaska, are dominated by the effects of Columbia Glacier at the head of the Bay. The basin between the glacier terminus and the terminal moraine (sill depth of about 22 m) responds as an ‘upside down’ estuary with the subglacial discharge of freshwater entering at the bottom of the basin. The intense vertical mixing caused by the bouyant plume of freshwater creates a homogeneous water mass that exchanges with the far-field water through either a two- or a three-layer flow. In general, the glacier acts as a large heat sink and creates a water mass which is cooler than that in fjords without tidewater glaciers. The predicted retreat of Columbia Glacier would create a 40 km long fjord that has characteristics in common with other fjords in Prince William Sound.  相似文献   

河口冲刷时间的研究进展与问题     

王世俊  李春初  唐兆民 《台湾海峡》2004,23(1):116-122

冲刷时间是表征河口水体交换的一个非常重要的物理量．本文在回顾潮汐河口冲刷时间研究现状的基础上，分析了影响冲刷时间的主要影响因子．结论表明冲刷时间不仅是潮棱体和淡水径流量的函数，而且与河口形态、天气要素密切相关，各要素之间的非线性关系更增加了冲刷时间研究的复杂性．在今后的研究中，应以河口界面的观点，加强河口冲刷时间界面机制的研究，并注重人类活动对冲刷时间的影响．  相似文献   

Spatial dynamics of estuarine water surface temperature from airborne remote sensing     

Richard D. Hedger  Tim J. Malthus  Andrew M. Folkard  Peter M. Atkinson 《Estuarine, Coastal and Shelf Science》2007,71(3-4):608-615

This paper examines the applicability of airborne remote sensing to the characterization and quantification of the spatial dynamics of water surface temperature (WST) within estuaries. For this, a series of successive airborne Thematic Mapper thermal images was acquired of Kirkcudbright Bay, an estuary in the United Kingdom, on two dates. Spatial dynamics were determined by two techniques: (1) qualitatively, which involved interpreting features ‘by eye’; and (2) by the velocimetric technique of maximum cross correlation (MCC). Qualitatively, complex spatial dynamics were identified over a wide range of spatial and temporal scales, associated with the creation and dissipation of eddies, and the convergence and divergence of fronts, all of which were superimposed on the synoptic tidal flow. MCC was effective for producing synoptic velocity fields, but the minimum cell size was constrained by image noise, limiting the ability to analyze small-scale spatial dynamics. The effectiveness of MCC was related to the ratio of spatially correlated variance to spatially independent variance, as estimated from the variogram. Suggestions for optimizing the application of airborne remote sensing to estuarine spatial dynamics are presented.  相似文献   

河口水Cu²⁺, Zn²⁺的分析、形式、分布、毒性与生态环境   总被引：4，自引：1，他引：4  

顾宏堪 《海洋与湖沼》1996,27(3):336-339

生物毒性实验Ｃｕ＾２＋，Ｚｎ＾２＋等浓度与生物死亡率相关模式表明，海水中加入的Ｃｕ＾２＋，Ｚｎ＾２＋等浓度逐渐增高，生物死主恨率相应增高，同一浓度下，死亡率随时间（２４，４８，７２，９６ｈ）的增加逐步增高，实验加入Ｃｕ＾２＋仅１μｇ／Ｌ和Ｚｎ＾２＋仅５μｇ／Ｌ本底浓度时，其毒性即已开始遵循相关模式。因此，比天然水含量仅高１，２倍的Ｃｕ＾２＋，Ｚｎ＾２＋离子的污染及毒性，就足以破坏鱼虾在河口的产卵，  相似文献   

福建九龙江口红树林造林遇到的问题   总被引：4，自引：1，他引：4  

薛志勇 《湿地科学与管理》2006,2(3):54-57

中国的红树林在过去50年里面积锐减了近70%,恢复和发展红树林迫在眉睫,红树林人工造林是必由之路。福建九龙江口湿地资源丰富,然而在红树林造林上却遇到了一些问题,这些问题阻碍了九龙江口红树林的恢复和发展,应该引起相关部门的关注。  相似文献   

Holocene stratigraphy-of the Lower Ganges-Brahmaputra River delta in Bangladesh     

Sirajur Rahman KHAN  Md Badrul ISLAM 《Frontiers of Earth Science》2008,2(4):393-399

Major part of the Holocene Ganges-Brahmaputra delta occupies the southern and southwestern part of Bangladesh with a smaller part extending beyond the international boundary in the west. Five facies assemblages are documented in the lower deltaic plain in five different depositional environments: levee or levee complex, bil or depression, abandoned meander belt, interdistributary plain and estuarine plain. The thickness of the Holocene sediments ranges from 30 m to 70 m in the deltaic plain, usually floored by the Pleistocene stiff clays, with the exception of the abandoned meander belt deposit where Holocene channel sand deposited directly on the Pleistocene sand. Radiocarbon dates indicate that low-rate sedimentation has occurred in the northern part, where 4-6 m thick sediments were deposited since the mid-Holocene, whereas 10-30 mthick sediments were deposited in the southern part during the same span of time. In addition, significant coastal subsidence (3 mm/a on average), added by sea-level rise (1.5 mm/a, conservative rate) occurs in the study area, which serves as a negative factor in degrading the coastal plain of Bangladesh in the future, while taking into consideration the weaker sedimentation in the area.  相似文献   

基于遥感和GIS的上海市滩涂湿地资源近期变化分析     

李贵东  周云轩  田波  刘志国  郑宗生 《吉林大学学报(地球科学版)》2008,38(2):319-323

利用多期Landsat-5 TM影像,结合植被分带信息、地物波谱特征和实地调查数据,提取上海地区滩涂湿地分布及其覆盖信息;在ArcGIS软件支持下,综合多期遥感影像解译结果和相应时段的水下地形信息,对上海市滩涂湿地空间分布及其变化进行分析。结果表明,近15年来上海市滩涂围垦量在不断增加;尽管滩涂湿地仍在继续淤涨,但淤涨速度明显减缓,且慢于围垦速度,这导致中高潮滩涂面积不断减少。  相似文献   

Behaviour of colloidal trace metals (Cu, Pb and Cd) in estuarine waters: An approach using frontal ultrafiltration (UF) and stripping chronopotentiometric methods (SCP)     

Matthieu Waeles  Virginie Tanguy  Gaëtane Lespes  Ricardo D. Riso 《Estuarine, Coastal and Shelf Science》2008,80(4):538-544

The frontal cascade ultrafiltration (UF) technique in conjunction with stripping chronopotentiometry (SCP) has been evaluated for determining the colloidal distribution of Cu, Pb and Cd in estuarine waters. Metallic concentrations in seven size fractions (0.45 μm–0.22 μm; 0.22 μm–300 kDa; 300–50 kDa; 50–30 kDa; 30–10 kDa; 10–5 kDa; <5 kDa) were determined with the aim to investigate their changes along the salinity gradient of the Penzé system (NW France). These data, completed by analysis of the total dissolved metals at 10 stations over the whole freshwater–seawater mixing zone, provided some insights in the removal and addition processes that affect Cu, Pb and Cd in estuaries.  相似文献   

秦皇岛河口沉积物砷形态分布特征     

张连凯  杨慧  路国慧  张尊举  郝冬亮 《海洋科学》2012,36(9):102-107

河口沉积物在陆源砷向海洋输送过程中具有源和汇的双重作用,分析砷在河口沉积物中的存在形态和分布特征对于掌握砷的毒理效应和污染评价具有重要意义.通过野外调查和样品采集,对秦皇岛典型河流河口沉积物中砷的质量比进行了测定,并采用Tessier五步连续提取法对砷在沉积物中的存在形态进行了提取分析.结果表明,汤河河口表层沉积物中砷的质量比为35.73~46.63 mg/kg,戴河河口表层沉积物中砷的质量比为13.60~16.00 mg/kg,汤河河口沉积物砷含量明显高于戴河河口.总砷含量随沉积深度的增加而有降低的趋势.各形态砷在沉积物中的分布特征基本一致,即以残渣态为主,占其总量的87%以上,其他各形态相对含量较小,其中可利用性最强的可交换态含量最小,平均为1.04%.各形态砷分布与沉积物的pH和有机质含量有一定的相关关系, pH和有机质含量的改变将会影响砷的形态分布特征.  相似文献