Observations on the surface water characteristics in the western Irish Sea: July 1977     

J. Beardall  P. Foster  D. Voltolina  G. Savidge 《Estuarine, Coastal and Shelf Science》1982,14(6):589-598

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Modelling nitrogen and phosphorus cycles and dissolved oxygen in the Zhujiang Estuary Ⅰ.Model results     

管卫兵  王丽娅  许东峰 《海洋学报(英文版)》2001,(4)

rmIoxThe averag annual dischaIge of the Zhujiang Xiver is 3. 32 x l0ll m3, which ranks theZhujiang River just end to the Changjiang River in China. The dischnye occutring duringthe fltal m between APril and ffepteTnber accounts for 80% of the yearly total. The Zhu-jiang hiver has a yeaIy sediment load of about 1 x l08 tons, which also concentrates in theM arn (Zhao, l990; Chen et al., 1998). The Zhujiang Xiver delta,which has l2 cities ofdifferent sizes and more than 40 towns with a po…  相似文献   

Analysis of seabed instability using element free Galerkin method     

J.G. Wang  M.R. Karim  P.Z. Lin 《Ocean Engineering》2007,34(2):247-260

Wave-induced seabed instability, either momentary liquefaction or shear failure, is an important topic in ocean and coastal engineering. Many factors, such as seabed properties and wave parameters, affect the seabed instability. A non-dimensional parameter is proposed in this paper to evaluate the occurrence of momentary liquefaction. This parameter includes the properties of the soil and the wave. The determination of the wave-induced liquefaction depth is also suggested based on this non-dimensional parameter. As an example, a two-dimensional seabed with finite thickness is numerically treated with the EFGM meshless method developed early for wave-induced seabed responses. Parametric study is carried out to investigate the effect of wavelength, compressibility of pore fluid, permeability and stiffness of porous media, and variable stiffness with depth on the seabed response with three criteria for liquefaction. It is found that this non-dimensional parameter is a good index for identifying the momentary liquefaction qualitatively, and the criterion of liquefaction with seepage force can be used to predict the deepest liquefaction depth.  相似文献   

Protracted Environmental Issues on a Proposed Titanium Minerals Development in Kenya's South Coast     

J. O. Z. Abuodha  P. O. Hayombe 《Marine Georesources & Geotechnology》2006,24(2):63-75

This study takes cognizance of the fact that the TIOMIN (TIOMIN Resources Inc. of Canada) project has resulted in controversy over its handling of environmental issues and especially the Environmental Impact Assessment (EIA). The authors address many of the protracted issues that have slowed the development of the mining project in Kwale. The main emphasis is on the impacts of the mining and mineral separation processes on the environment, including the governing legislation, the role of consultation and public participation, and socioeconomic issues. In their public documents TIOMIN has specified neither the type of minerals it wants to extract from the area nor their chemical composition. It is well known, however that the titanium minerals and zircon targeted have impurities of iron, thorium and uranium. In the absence of an Environmental Management Plan, the effects of stockpiling radioactive wastes and other impurities that could possibly lead to environmental degradation in both the terrestrial and marine environments have not been publically addressed. The measures proposed to mitigate ecological damage as a result of the establishment of a minerals processing plant in the area seem inadequate. Pollution resulting from accidental spillage or breakage could have significant impact on marine life and residents living near the mining site. Other issues that have not been addressed satisfactorily pertain to the use of surface and underground water. The area already faces a huge water deficit and the calculations presented on aquifer recharge and stream flow rates do not indicate the large quantities of water that would be required in the mineral processing plant. The project, if approved in its present state, risks violation of international conventions. Furthermore, it could cause a conflict between Kenya and Tanzania in the event of an oil spill at the proposed ship loading facility at Shimoni. The proposed mining area includes the district's most fertile land, is home to many fisherfolk and is a major tourist destination. An analysis of the effects of this project on other available opportunities must be thoroughly understood to ascertain the economic and environmental benefits and costs of the mining venture. The proposed compensation rate of $1,000 per acre, for resettlement for example, appears to be grossly inadequate. Compensation should take into account family size and structure family assets and the cost of relocation.  相似文献   

Nutrients and zooplankton composition and dynamics in relation to the hydrological pattern in a confined Mediterranean salt marsh (NE Iberian Peninsula)   总被引：4，自引：1，他引：4  

Anna Badosa  Dani Boix  Sandra Brucet  Rocío Lpez-Flores  Xavier D. Quintana 《Estuarine, Coastal and Shelf Science》2006,66(3-4):513-522

The role of the hydrological regime in the nutrients and zooplankton composition and dynamics has been analysed in five lagoons of La Pletera salt marshes (NE Iberian Peninsula) during a complete hydrological cycle (2002–2003). Two of the lagoons have their origin in the old river mouths while the other three were recently created in the framework of a Life Restoration project. This fact has also allowed us to study the effect of the lagoon age on nutrient and zooplankton composition and dynamics. The salt marsh hydrology is determined by a prolonged period of confinement without water inputs, irregularly interrupted by sudden water inputs due to flooding events (sea storms or intense rainfalls). While the dynamics of oxidized nitrogen compounds in the lagoons depends on the water inputs variability within each hydrological cycle, the internal load of phosphorus, total nitrogen and organic matter is related more to the cumulative mechanisms during the confinement periods. Accumulation processes may be easily related to lagoon age, since old lagoons have higher content of nutrients and organic matter, suggesting that these lagoons progressively accumulate nutrients during the successive confinement events. This is the usual case for most Mediterranean salt marshes without an artificially manipulated water regime. The zooplankton community in La Pletera integrates the effects of both the hydrological regime and the lagoon age since the former determines the temporal pattern of the main zooplankton species and the latter explains differences in composition and structure between old and new lagoons.  相似文献   

九龙江流域水葫芦打捞去除水体营养盐模型研究   总被引：1，自引：0，他引：1  

陈彬  赵由才  王金坑 《台湾海峡》2007,26(3):327-333

水葫芦被收获时,水体中的营养盐也将包含在植物组织中而被去除.本研究首先通过野外实验和参考国内外有关文献,建立了九龙江流域水葫芦生长数学模型和持续生产模型,确定了模型的各有关参数:水葫芦生长容量K值为25.6 kg/m2、最大生长速率rmax为0.12d-1;水体中氮和磷的半饱和系数hN和hP值分别为0.2和0.03;水葫芦最低生长温度(mθin)为7℃,最适水温(oθpt)为30℃,最高生长温度(θmax)为40℃.随后采用所建立的模型计算了研究区水葫芦打捞的营养盐去除效果,研究区面积6 000m2的水体实施水葫芦打捞策略后,1a所能收获的水葫芦最大产量为9.18×105kg,去除的TP为214.4kg,TN为966.6kg.  相似文献   

渤海生态动力过程的模型研究 Ⅱ.营养盐以及叶绿素a的季节变化          下载免费PDF全文

刘浩  尹宝树 《海洋学报》2007,29(4):20-33

利用在本系列研究第一部分中所建立的耦合的生物物理模型,模拟了渤海浮游植物生物量和营养盐含量的年度循环特征.模拟结果显示:藻类的春季水华是由经过一冬积累在水体中的营养盐导致,而水华开始的时间在浅水区明显早于深水区,对此深水区水体层化结构的形成可能起着重要作用;另一方面,河载营养盐与悬起的沉积物所释放的营养盐是诱发夏季水华的共同原因.基于模型结果,我们还发现:渤海的浮游植物动力特性就整体而言依然受无机氮限制,但是在莱州湾,磷限制特性表现得非常明显,这主要是由于每年黄河都要携带大量的无机氮进入海水,从而导致莱州湾营养盐的氮磷比已远远超过16.  相似文献   

中国南极长城湾及附近海区1993/1994年夏季表层水样无机氮、磷酸盐的浓度及其分布状况     

陈皓文  朱明远  洪旭光  陆华  袁峻峰 《海洋湖沼通报》1996,(4)

1993／1994年南极夏季对中国南极长城湾及附近海区表层海水四种营养盐浓度及其分布状况作了调查。结果表明，NH4－N、NO3－N、NO2－N及PO4－P的大致浓度分别是2．13、7．07、0．74和1．12μg·dm-3。一般来说，湾内高于湾外氮盐于12月份常出现高值。四种形态的无机盐类之最高、最低浓度出现的时间和站位不尽一致。∑N／P递减次序大致是12月，2月，1月。水温变化与NH4－N、PO4－P浓度和∑N／P的变化常较一致，而与NO2－N则常不一，一些站位上营养盐浓度偏低可能与浮游植物摄取有关。结果显示了调研海区的浅水内湾特征。浮游植物所需营养充分。该湾仍维持正常状态。  相似文献   

钦州湾内湾贝类养殖海区水环境特征及营养状况初探     

韦蔓新  童万平  赖廷和  何本茂 《海洋科学进展》2001,19(4):51-55

根据 1 998年 1 0月和 1 999年 5月的调查资料 ,阐述了钦州湾内湾水环境特征及 N/P的变化 ,以 DIN、DIP、COD和 Chl- a为富营养化指标 ,用营养状态质量指数 (NQI )分析探讨了该湾的营养状态 ,并从富营养角度讨论了该湾的污染程度  相似文献   

营养盐水平对四种海洋浮游硅藻胞外多糖产量的影响   总被引：10，自引：0，他引：10  

王大志  黄世玉  程兆第 《台湾海峡》2003,22(4):487-492

4种海洋浮游硅藻(牟勒氏角毛藻、海链藻、三角褐指藻和新月菱形藻)培养在改进的f／2培养基中，研究了不同氮、磷和硅营养水平对它们胞外多糖产量的影响．结果表明，硅藻胞外多糖的生产和释放具有种间特异性，角毛藻和海链藻胞外多糖的生产和释放主要在静止期，而三角褐指藻和新月菱形藻在指数生长期前期和静止期都能生产和分泌较高的胞外多糖；培养液中低浓度磷减少了4种硅藻在静止期胞外多糖的产量，但增加了角毛藻在生长期前期胞外多糖的产量；氮浓度的降低增加了三角褐指藻在指数生长前期胞外多糖的产量，但减少了其他3种藻类胞外多糖的产量；硅浓度的降低对4种硅藻胞外多糖的产量影响不大，在一定程度上还促进了静止期胞外多糖的生产．本研究表明，营养盐水平对硅藻胞外多糖生产的影响因种类和细胞所处生长期不同而存在着很大的差异．  相似文献