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1.
纳污海水中COD生化降解过程的模拟试验研究 总被引：6，自引：0，他引：6
1995年5－11月期间,采取渤海湾海水,控制不同的试验水温和不同的有机物起始浓度,采用试验室模拟方法,测定COD生化降解曲线。依据COD降解动力学理论,得出不同环境条件下的COD生化降解动力学参数。经过归纳综合,建立了纳污海水中COD的生化降解动力学参数方程式。试验结果显示,渤海湾天津近岸排海污水COD生化降解过程符合一级反应动力学模型,其降解速率系数足值介于0．023－O．076d-1之间。k值受温度变化的影响较大,温度越高,k值越大。 相似文献
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随着全球气候变暖,风暴潮在沿海地区的频率和强度均可能增长,由此引发的海水垂向入侵可能会造成大面积的含水层淡水咸化。同时,由人类活动引起的沿海虾塘咸水养殖规模日益增长,由此引发的咸水垂向入侵可能会导致沿海地区地下水水质及生态环境的恶化。虽然已有一部分学者在海水(咸水)垂向入侵的研究中取得了成果,但由于海水(咸水)垂向入侵过程复杂,其对地下水咸化及恢复规律依然有待深入研究。文章阐述了海水垂向入侵的危害及前人的研究办法,总结了他们的研究成果并得出了海水垂向入侵的影响因子,指出了洪水和养殖活动对沿海地区含水层的威胁。得出的结果如下:研究海水垂向入侵常用的方法包括室内试验和数值模拟;海水垂向入侵主要与地形地貌、含水层性质和水文气象条件有关;虾塘养殖等人类活动可能会成为垂向咸水入侵的潜在来源。建议未来在海水垂向入侵研究中将多种现场观测实验方法结合起来。数值模拟应注重与现场观测实验数据相互验证,模型简化的方式有必要仔细考虑。虾塘养殖等人类活动可能造成的垂向咸水入侵问题应更多地受到关注。 相似文献
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修建海岸水库是满足滨海地区淡水资源的保障的一个重要方式,为了进一步分析海岸水库的建立对滨海含水层的海水入侵的影响,采用SUTRA(saturated-unsaturatedtransport)模型建立具有代表性的二维海岸模型开展定量和定性研究,结果表明:潮汐作用抑制底层盐水楔的入侵,加快海陆物质交换;实例中计算表明建坝后,海岸水库坝体的建立加剧了海水入侵;水库水位在平均海平面以下时,潮汐动力因素占主导,海水入侵严重且随着水位抬高,海水入侵程度基本保持不变,应注意海水入侵的防治;库区水位在平均海平面以上时,海水入侵程度随着库区水位的抬高而减少,可以调节水库水位进行滨海含水层的海水入侵的防控;海岸水库在建设中存在一个控制水位,当水库水位在控制水位以上,库区水体盐度和含水层淡水储量能得到保证;库区高水位时内陆物质运移时间较长,运移区域较广,氮类污染物易在库底含水层堆积,需重视含水层的地下水污染防治。 相似文献
4.
M.D. MacKinnon 《Marine Chemistry》1979,8(2):143-162
A method based on a dynamic head-space extraction and high-temperature oxidation of the trapped organic matter is described for the determination of the volatile organic carbon (VOC) concentration in seawater. The VOC concentrations in various geographic regions have been measured and calculated as a fraction of the total organic carbon (VOC/TOC). The VOC concentrations ranged from 15–60 μg C/liter in most oceanic areas. This volatile component was found to be a small fraction (1.5–6%) of the TOC. The VOC concentrations are highest in coastal regions and in the surface zone while the VOC/TOC ratio is relatively constant with depth and location. The volatile organic components may be important to the cycling of organic matter in sea water and the dynamics of this role have been postulated. 相似文献
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湍流局地平衡假设的新推论--齐次湍流动能输运方程封闭模型与应用(Ⅱ) 总被引：2，自引：1，他引：1
在湍流局地平衡假设下 ,建立了齐次湍能输运方程封闭模型 (HKE) ,并在平板边界层的两种经典流动中加以检验 ,给出 HKE封闭下的流速、湍流动能和湍流混合系数剖面的形式解。结果表明 ,HKE可以避免在流速剪切为零时的无湍流混合问题 ,其解与 L aufer湍流实验吻合 ,因而HKE模型比混合长理论有更合理的内涵。文中还给出 HKE封闭的浅海动力学模型 ,以湍应力和水位梯度力的平衡为运动的基本受力平衡 ,进行了模型的量阶分析和运动分析 :当阻尼频率和运动频率同量阶时 ,惯性运动不可忽略 ;在潮振荡占优的浅海中 ,对流非线性相对于惯性运动为小量 ;当阻尼频率足够大时 ,科氏力项相对于湍应力也可能为小量。 相似文献
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考虑人类活动的海岸线分类体系 ——近期浙江省海岸线调查的实践与思考 总被引：1，自引：1，他引：1
海岸线是海陆分界线,定义为多年平均大潮高潮位的痕迹线,兼具海洋与陆地的空间资源管理界限功能。海岸线具有重要的生态功能和资源价值,其功能和价值源于所依附的海岸带。随着海岸带地区的经济与社会快速发展,海岸带资源的保护与开发的矛盾日益凸显。在此背景下,中国构建了以自然岸线保有率为核心的海岸线管理办法。2018年实施的浙江省地方标准《海岸线调查统计技术规范(DB33/T2106—2018)》提出了海岸线的三级分类体系,包括自然岸线、人工岸线和河口岸线3个一级类。该《规范》综合反映了海岸线的科学定义和国家需求。首先,该《规范》给出海岸线定义是"平均大潮高潮时水陆分界的痕迹线",突出了"大潮高潮位"和"痕迹线"对海岸线界定工作的指示意义。其次,该《规范》将自然岸线定义为"由海陆相互作用形成的海岸线",由此推论,人工岸线的地貌动力学功能是隔断了原有的海陆相互作用。第三,该《规范》提出了"原生自然岸线"、"自然恢复的岸线"和"整治修复的岸线"等概念,将曾经受过人类活动影响但恢复了(或拥有了)某种自然海岸形态特征和生态功能的岸线纳入自然岸线的统计口径。由于河口岸线是没有"水陆分界痕迹"可循的特殊类型,现有的海岸线定义未能体现河口岸线的内涵,因此我们建议将海岸线的定义扩展为"平均大潮高潮位的海陆分界痕迹线,以及河流入海口附近按一定规则人为划分的海域与陆域水体的分界线"。从海岸带地貌动力学的角度来看,海岸线的类型和变化主要受地质基底、海平面位置、沉积物供应条件和海岸动力环境等因素影响。因此,海岸线的定义和分类应该综合考虑这四个因素,而人类活动主要从海岸动力作用环境和沉积物供应条件两方面影响海岸带系统状态。 相似文献
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相对海平面上升对中国沿海地区的可能影响 总被引：6，自引：0，他引：6
本文论述了相对海平面变化研究的重要性,并在IPCC提供的全球海平面变化背景值之上,给出中国未来几十年相对海平面变化的预测值。中国大河三角洲地区未来几十年相对海平面皆呈上升趋势,但幅度不同。因此,充分认识相对海平面上升将导致的危害就显得极为重要和迫切。相对海平面上升将对中国沿海地区产生以下影响：(1)导致海岸侵蚀,扩大侵蚀范围;(2)风暴潮强度与频率增加：(3)沿海低地与湿地被淹没;(4)海水入侵加剧,范围扩大,水资源和水环境遭到破坏;(5)防汛工程功能降低,洪涝灾害加剧。因此,沿海地区政府决策应考虑未来相对海平面变化的影响。 相似文献
10.
We present results from a series of piezometers installed in the foreshore flat and mangrove environments of the Gillman Marshes, South Australia in an interdisciplinary study of the propagation of the ocean tide into the coastal aquifers. A unique feature of the analysis is that all water level records were harmonically analysed so that the behaviour of the four major tidal constituents could be independently examined. The main findings were that: (1) the decay of the groundwater tide in the coastal aquifers was greater than that predicted by the Ferris solution. A theoretical model has been developed and applied to the study site. The model suggests that this behaviour is due to the occurrence of a time delay in the Darcian response in the shelly and muddy sand substrate; (2) when the tide is incident over a gently sloping bank, the time delay in response gives rise to a spiked signal in which high water is confined to a small fraction of the tidal cycle; and (3) at the coastal interface tidal propagation across a sloping bank causes a rise in the water table relative to mean sea level which is proportional to the variance of tidal elevation and inversely proportional to the decay constant of the groundwater tide. The model developed in this study is also applicable to other coastal groundwater systems with tidal influence. 相似文献
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地下水监测及数理分析是地下水动态研究的主要方法。但目前海岸带地区多以陆域地下水监测为主,海域部分尤其具有多层含水层系统的海底地下水缺少直接监测数据。本研究通过海域钻孔ZK03与ZK08实时监测不同层位海底地下水动态以及海洋潮汐变化,结合其地层结构和沉积演化背景,分析莱州湾海底地下水动态特征并揭示其影响机制。研究结果表明,莱州湾海底地下水动态具有周期性和分层性特征;全新世含水层与海水关系密切,其海水入侵界面垂向上厚10 m左右。海底地下水分层与沉积地层划分大致相同,其动态特征是在地层结构及沉积演化环境影响下,降水、径流及潮汐驱动不同层深地下水间或地下水与海水间混合作用的结果。本文初步构建了海底地下水分布模式,探讨区域地下水与海水的相互作用关系。莱州湾海底地下水动态研究对于深入分析海(咸)水界面变化机制及探索海底地下水排泄具有推动作用。 相似文献
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基于GOCI影像的长江口及其邻近海域CDOM遥感反演及其日内变化研究 总被引：1，自引：1，他引：0
采用静止轨道海洋水色卫星（GOCI）数据对长江口及其邻近海域有色溶解有机物（CDOM）反演。以QAA-CDOM算法为基础,根据实测数据,利用BP神经网络模型来拟合QAA-CDOM算法中需要针对长江口水体进行优化的悬浮颗粒后向散射系数bbp与吸收系数ap的关系,从而准确估算CDOM的浓度。结果表明,反演结果准确度较高,平均相对误差为0.35。基于GOCI日内连续成像的优势,选取2014年3月15日8景GOCI影像,利用优化后的QAA-CDOM-BP算法,对长江口及其邻近海域CDOM的日内变化进行反演和分析,得到的变化规律如下:长江口及其邻近海域的CDOM日变化主要受潮流、长江径流等共同影响。长江口内CDOM浓度在涨潮期高于退潮期,由于受长江冲淡水的作用,CDOM从口外往外海区呈现逐渐递减趋势。 相似文献
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福建沿岸海域赤潮发生特点及防治措施 总被引：17，自引：2，他引：17
根据多年来福建沿岸海域发生赤潮的情况及相关资料，概述了该海域赤潮发生的主要趋势、时间、区域、种类和危害等特点，分析和讨论了赤潮发生的自然因素和人为因素；并指出赤潮防灾和减灾工作中存在的主要问题是海洋综合管理力量薄弱，海洋法律法规不够健全，海洋执法能力有待加强，海洋事业经费投入不足．在此基础上提出了防治福建沿岸海域赤潮灾害的如下措施和建议：进一步调查和研究赤潮发生的类型并分析其主要成因；建立健全福建省近岸海域环境监测网络和海洋环境监测系统，大力开展具有福建区域特色的赤潮生物及其有害赤潮发生机理等科学研究；控制陆源污染，减少含氮污染物的排放总量和入海量，提倡和推广使用农家肥，提高生活污水的处理效率；认真研究和分析港湾的环境容量，合理开发福建的海水养殖业；加强围填海等涉海工程对海水动力学影响的研究，以及加强对船舶压仓水等带来外来赤潮生物影响的研究等． 相似文献
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良好的环境质量是厦门成为一个宜居和滨海旅游城市的重要基石。自日本福岛核事故发生和福建省核电站陆续运行之后,厦门邻近海域潜在的核污染风险受到公众和管理部门的关注。本研究测定了2015年2月和8月厦门邻近海域海水和海洋沉积物中主要放射性核素的含量水平,并据此评价了该海域的环境放射性质量状况。结果表明海水中总铀、90Sr、226Ra、137Cs处于我国海洋放射性水平变化范围以内,无明显季节差异,其他放射性核素58Co、60Co、134Cs、110mAg、59Fe、54Mn、65Zn均未检出,海水中90Sr和137Cs的活度最大值远低于国家海水水质标准限值,海洋沉积物中放射性核素活度水平亦在我国海洋放射性水平变化范围以内。利用我国现有的海洋放射性环境质量评价方法对厦门邻近海域放射性质量状况进行分级评价得出其海水放射性质量为2级,海洋沉积物放射性环境质量为1级,均属于安全级别。研究结果表明2015年在厦门附近海域未观测到放射性污染现象。 相似文献
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《Marine Policy》2017
The development of seawater desalination plants to increase water reliability in coastal areas poses a threat to the health of near shore marine ecosystems and may affect the effectiveness of marine protected areas (MPAs) that have been established to meet international conservation targets. This paper applies a multi-criteria analysis approach to quantify stakeholder groups’ priorities for seawater desalination plants that have been proposed in communities adjacent to a National Marine Sanctuary. All groups placed the highest importance on minimizing environmental impacts on protected areas and endangered species that could be affected by water intake and brine discharge emphasizing the need for integrated land and sea conservation. Minimizing socio-economic impacts on coastal communities was much less important. Stakeholders also weighted reducing pressure on water levels in rivers, streams, and aquifers as more important than increasing water for residential consumption, which may foster coastal growth rather than replacing water taken from other sources. The study further revealed differences in the importance of multiple management objectives among stakeholder groups, which highlights the need to elicit distinct priorities of all groups to understand concerns and potential conflicts of desalination with existing marine users. The analysis of consistency ratios revealed that around half of all surveyed stakeholders had high inconsistencies in their responses, which suggests either a lack of understanding of desalination, or reflects the complexity of establishing desalination plants in coastal areas adjacent to a marine protected area. 相似文献
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基于2018年早春和夏季长江口邻近海域的调查数据,分析溶解氧(DO)的时空分布,并讨论其影响因素.结果表明,夏季DO浓度变化范围为1.58～9.37 mg/L,浮游生物光合作用产生的DO是夏季表层水体过饱和的主要因素;夏季调查海域受台湾暖流北上引起海水层化加强,同时水体富营养化导致表层生物大量繁殖所引起有机碎屑的沉降和耗氧分解作用是底层低氧区存在的主要因素.夏季在台湾暖流影响下底层水体表观耗氧量(AOU)与营养盐成正相关关系,底层有机物耗氧降解过程与营养盐的再生密切相关.早春DO浓度变化范围为7.90～10.1 mg/L,长江口外北部海域和浙江近岸海域海水混合均匀,DO浓度主要受温度控制,而台湾暖流影响区海水出现层化现象,其低DO含量也为低氧区的形成奠定了基础. 相似文献
17.
Katharine R. Hendry Michael P. Meredith Christopher I. Measures Damien S. Carson Rosalind E.M. Rickaby 《Estuarine, Coastal and Shelf Science》2010
The use of dissolved Al as a tracer for oceanic water masses and atmospheric dust deposition of biologically important elements, such as iron, requires the quantitative assessment of its sources and sinks in seawater. Here, we address the relative importance of oceanic versus atmospheric inputs of Al, and the relationship with nutrient cycling, in a region of high biological productivity in coastal Antarctica. We investigate the concentrations of dissolved Al in seawater, sea ice, meteoric water and sediments collected from northern Marguerite Bay, off the West Antarctic Peninsula, from 2005 to 2006. Dissolved Al concentrations at 15 m water depth varied between 2 and 27 nM, showing a peak between two phytoplankton blooms. We find that, in this coastal setting, upwelling and incorporation of waters from below the surface mixed layer are responsible for this peak in dissolved Al as well as renewal of nutrients. This means that changes in the intensity and frequency of upwelling events may result in changes in biological production and carbon uptake. The waters below the mixed layer are most likely enriched in Al as a result of sea ice formation, either causing the injection of Al-rich brines or the resuspension of sediments and entrainment of pore fluids by brine cascades. Glacial, snow and sea ice melt contribute secondarily to the supply of Al to surface waters. Total particulate Al ranges from 93 to 2057 mg/g, and increases with meteoric water input towards the end of the summer, indicating glacial runoff is an important source of particulate Al. The (Al/Si)opal of sediment core top material is considerably higher than water column opal collected by sediment traps, indicative of a diagenetic overprint and incorporation of Al at the sediment–water interface. Opal that remains buried in the sediment could represent a significant sink of Al from seawater. 相似文献
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The objective of this paper is to present the effect of sediment characteristics on the dynamic response of sea walls and breakwaters during earthquakes. A finite-difference method is used to calculate the earthquake-induced hydrodynamic pressures of seawater and the pore water in seabed sediment. The water-filled soil mixture is used to model sediment and back-fill soil. The dynamic response of a rigid coastal structure induced by constant ground acceleration is studied, using variable sediment depths and porosity. The dynamic characteristics of the water–embankment–sediment system are investigated, applying four earthquake-records as exciting forces. The result of a quay-walled caisson demonstrates the significance of the seismic-induced dynamic force and the seismic effects should be considered for the design of coastal structures in seismic zone. The damaged wharves of Taichung Port during Chi-Chi earthquake, 21 September 1999 is also reported in the paper. 相似文献
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《Estuarine, Coastal and Shelf Science》2003,56(3-4):781-793
Estuaries are often seen as important filters between land and the sea for inorganic and organic nutrients. This paper aims at estimating the estuarine fluxes of dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and dissolved silicate for the major oligothrophic and pristine rivers running into the Bothnian Bay (BB) and the Bothnian Sea (BS), the northern subarctic subbasins of the Baltic Sea. Long-term data sets for these rivers and their estuaries as well as for the BB and BS were analyzed to assess whether these estuaries are sinks for inorganic nutrients. Most studied estuaries can be characterized as salt wedge estuaries with little exchange between the fresh seaward-flowing river water and the inward-flowing seawater. Estimates of water transit times ranged between 1 and 14 days. In most estuaries of the BB, N-depleted river water meets P-depleted seawater during the growth period. These findings were corroborated by mixing diagrams showing that the inner areas of the estuaries were N-depleted in summer. In the BS, on the other hand, both rivers and seawater were mostly N-depleted during summer. Thus, for most estuaries of this region of the Baltic Sea, primary productivity is presumably lower than or equal to that of offshore. The low productivity is also reflected in the sediments. The coastal sediments did not differ from the offshore stations in accumulation rates as well as the content of organic matter and nutrients, indicating that estuarine nutrient burial is not always higher as normally observed in other temperate systems. Finally, the estuaries of the pristine rivers in the northernmost part of the BB import DIN during summer, whereas the estuaries of the rivers in the BS import DIP during winter, from the sea. 相似文献