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菜坨子岛位于大连市长海县,为无居民海岛,功能定位为渔业用岛。依据无居民海岛生态系统的特点和渔业用岛功能定位,文章使用压力-状态-响应模型设置3层指标体系,对菜坨子岛生态状况进行评价。指标评价方法采用专家评价法及单因子环境质量指数法、综合评价指数法等计算各级权重值和指标值。基于2015年现场调查数据,采用层次分析法对压力-状态-响应模型进行计算,得出菜坨子岛年生态状况分值及评价结果。结果表明,菜坨子岛总体状态为“优”(分值为0.811 1)。此外,经过对评价指标进一步优化后,可将该评价方法推广到对其他渔业用无居民海岛的生态状况评价,为其开发和保护提供依据。 相似文献
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围填海造陆引起的海岛周围海域海洋生态系统服务价值损失——以浙江省洞头县为例 总被引:3,自引:1,他引:2
利用SPOT5、IRS-P5 高分辨遥感数据、海图并结合实地调查, 以2004 年数据为基准, 分别获取了2008 年和2010 年浙江洞头县14 个有居民岛屿的岸线以及填海造地数据。根据填海工程造成海岛周围海域的供给、调节、支持、文化等多种服务损失构建生态服务价值损失估算模型, 采用直接市场法、替代花费法等方法评估了海岛造地导致的海洋生态系统服务功能价值损失情况, 结果表明: 洞头县2004~2010 年填海造地导致海岛周围海域的海洋生态系统服务价值损失为13 626.95 万元/a, 其中供给价值损失最大, 占价值总损失的87%, 从价值损失分布空间看状元岙岛周围海域损失最大, 其次是洞头岛,小门岛周围海域损失最小。因此, 在开发利用海岛资源时, 应对养殖、捕捞、港口、自然保护等海岛开发活动进行合理的规划和调控, 提高海岛资源的利用效率, 促进海岛经济和环境的可持续发展。 相似文献
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根据1990-1992年莱州湾部分海域的水质监测结果,利用模糊综合海水水质级数法,对该海域的水质现状进行了综合评价,并对主要污染因子及其分布、变化特征进行了讨论分析,评析结果表明:该海域的综合水质符合二类水质标准;湾内主要污染源是来自小清河、虞河、弥河、白浪河及三山岛的工业与生活污水,其中以小清河、弥河及三山岛为重;该海域的主要污染因子为石油类、无机氮、COD;水质污染的空间分布特征较明显,而年际变化则无明显规律。 相似文献
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台湾海峡西侧自闽江口至东山岛之间的近岸海域,分布着众多规模、大小不等的岛连岛,其中的平潭岛、东山岛和金门岛为大型岛连岛,均在全国十大海岛之列。此类岛连岛为全国沿海岛屿仅有,亦为台湾海峡西侧所特有。其成因属于陆海复合型——大陆岛与岛间波影区沉积复合型岛屿。但目前岛屿的传统分类,尚不能充分表达其特征和存在。需开展该类岛屿成因类型研究,完善岛屿分类,反映各类成因的岛屿特征。当前台湾海峡西岸正在进行的大规模开发的海岛,许多属于岛连岛,如平潭岛、东山岛等,研究其成因对该类海岛的保护管理和科学开发有着切实的指导意义。 相似文献
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由于厦门西海域独特的地理位置,周边城市规模扩大和经济发展,使得厦门西海域承受沉重的环境负载.本文根据厦门西海域功能特点,以及在对厦门西海域水质状况分析的基础上,分析了西海域对主要排海污染物的环境承载力.西海域无机氮和无机磷平均含量基本符合四类或超四类国家海水水质标准,西海域已无无机氮和无机磷承栽能力;西海域化学耗氧量、重金属(铜、铅、镉、汞和砷)和油类还存在相当的承载能力. 相似文献
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天津近岸海域海水富营养化评价及其主成分分析 总被引:4,自引:0,他引:4
于2013年7月对天津近岸海域海水营养盐和叶绿素a等水质因子进行采样调查,运用营养状态质量指数法和富营养化指数法对该海域海水富营养化水平进行评价,采用主成分分析法得出海水富营养化的驱动因子。结果表明,调查海域80.95%站位的无机氮以及61.90%站位的活性磷酸盐为劣四类海水水质;营养状态质量指数法评价与富营养化指数法评价结果基本一致:在北塘入海口周围近岸海域指数最高,其次为子牙新河入海口周围近岸海域,远岸海域的指数较低;影响调查海域海水富营养化的驱动因子为总氮和总磷。 相似文献
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为了了解黄河口埕岛油田周边海域的生态环境特征及变化趋势,采用单因子质量指数法和综合指数法对该油田周边海域海水和沉积物历年跟踪监测结果进行了评价,并对该油田周边海域海洋生物的变化情况进行了分析。结果表明:除2009—2011年无机氮,2011年磷酸盐外,埕岛油田周边海域历年监测水质要素均符合《海水水质标准》中第二类水质标准;历年监测沉积物要素均符合《海洋沉积物质量》中的一类标准。2006—2011年调查海域水质和沉积物油类含量的变化趋势与埕岛油田年产油量具有良好的对应关系。调查海域生物环境状况整体水平有所下降,海洋石油开发对埕岛油田周边海域的海洋环境造成了一定的负面影响。 相似文献
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海岛生态系统是海洋生态系统的重要组成部分。近年来,随着海岛人为活动数量不断增加,加速了对海岛生态环境的破坏,一些海岛生态失衡严重,生态系统受损加剧。而对受损海岛生态系统开展人工参与下的主动式生态恢复,是目前较为主流的恢复方法和手段,菩提岛整治修复项目正是基于上述修复理念开展并完成的。本文以菩提岛海岛及周边海域为研究区域,基于PSR模型,以RS方式为主要指标获取方式,构建了适用于我国海岛整治修复模式下的海岛生态系统健康评价体系,对其整治修复前后生态系统健康状况开展评价分析。结果显示:2008年,该岛生态系统健康值IEI为0.374 0,生态系统较脆弱,整体状况较差,亟须开展保护与修复工作;2014年,经岛体修复并趋于稳定状态后,该岛生态系统健康值IEI提升至0.673 8,生态系统较健康,处于稳定状态,但仍具有上升空间。经整治修复前后纵向对比,生态系统健康波动值ΔIEI为0.299 8,表明该岛生态系统经过修复后已有所好转。 相似文献
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Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明:土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
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Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested. 相似文献
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G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引:1,自引:0,他引:1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria ( 〉 99% ), but also between polar marine bacteria and bacteria from other aquatic environments ( ≥ 98.8% ), including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献
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The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments. 相似文献
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Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations. 相似文献