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51.
确定自然海岸特征是海岸修复中的重要内容,但是在开发后弃管的无居民海岛却面临缺少历史资料参考的困难。在大连普兰店湾中部前大连岛的研究证明,依据历史影像和现存海岸地质地貌情况可以分析确定原自然海岸位置及性质。1972年KH 卫星影像表明当时的前大连岛仍然保持自然海岸形态,海岸位置在2020年海岸后
方的岛屿陆域内部。结合2020年海岸地质考察结果可以进一步确定1972年的前大连岛东部、西部分布海蚀崖形式的基岩海岸,南部、北部则分布砾石质海岸。1972—2020年,前大连岛自然海岸全部变化为人工海岸,海岸长度也从约2.38 km 增加至约3.12 km。 相似文献
52.
Yazvenko SB McDonald TL Blokhin SA Johnson SR Melton HR Newcomer MW Nielson R Wainwright PW 《Environmental monitoring and assessment》2007,134(1-3):93-106
Exxon Neftegas Limited, as operator of the Sakhalin-1 consortium, is developing oil and gas reserves on the continental shelf
off northeast Sakhalin Island, Russia. DalMorNefteGeofizika (DMNG) on behalf of the Sakhalin-1 consortium conducted a 3-D
seismic survey of the Odoptu license area during 17 August–9 September 2001. A portion of the primary feeding area of the
endangered western gray whale (Eschrichtius robustus) is located in the vicinity of the seismic survey. This paper presents data to assess whether western gray whale bottom feeding
activity, as indicated by visible mud plumes, was affected by seismic operations. The mitigation and monitoring program associated
with the seismic survey included aerial surveys during 19 July–19 November 2001. These aerial surveys documented the local
and regional distribution, abundance, and bottom feeding activity of western gray whales. Data on gray whale feeding activity
before, during and after the seismic survey were collected, with the whales assumed to be feeding on the benthos if mud plumes
were observed on the surface. The data were used to assess the influence of seismic survey and other factors (including environmental)
on feeding activity of western gray whales. A stepwise multiple regression analysis failed to find a statistically significant
effect (α = 0.05) of the seismic survey on frequency of occurrence of mud plumes of western gray whales used as a proxy to evaluate
bottom feeding activity in Piltun feeding area. The regression indicated that transect number (a proxy for water depth, related
to distance from shore) and swell height (a proxy for sea state) were the only variables that had a significant effect on
frequency of whale mud plumes. It is concluded that the 2001 seismic survey had no measurable effect (α = 0.05) on bottom feeding activity of western gray whales off Sakhalin Island.
M.W. Newcomer, deceased 相似文献
53.
Classic island biogeographic theory predicts that equilibrium will be reached when immigration and extinction rates are equal.
These rates are modified by number of species in source area, number of intermediate islands, distance to recipient island,
and size of intermediate islands. This general model has been variously modified and proposed to be a stochastic process with
minimal competitive interaction or heavily deterministic. Predictive models of recovery (regardless of the end point chosen)
have been based on the appropriateness of the MacArthur-Wilson models.
Because disturbance frequency, severity, and intensity vary in their effect on community dynamics, we propose that disturbance
levels should first be defined before evaluating the applicability of island biogeographical theory. Thus, we suggest a classification
system of four disturbance levels based on recovery patterns by primary and secondary succession and faunal organization by
primary (invasion of vacant areas) and secondary (remnant of previous community remains) processes.
Level 1A disturbances completely destroy communities with no upstream or downstream sources of colonizers, while some component
of near surface interstitial or hyporheic flora and fauna survive level 1B disturbances. Recovery has been reported to take
from five years to longer than 25 years, when most invading colonists do not have an aerial form.
Level 2 disturbances destroy the communities but leave upstream and downstream colonization sources (level 2A) and, sometimes,
a hyporheic pool of colonizers (level 2B). Recovery studies have indicated primary succession and faunal structuring patterns
(2A) with recovery times of 90–400 days or secondary succession and faunal structuring patterns (2B) with recovery times of
40–250 days.
Level 3 disturbances result in reduction in species abundance and diversity along a stream reach; level 4 disturbances result
in reduction of abundance and diversity in discrete patches. Both disturbance types lead to secondary succession and secondary
faunal organization. Recovery rates can be quite rapid, varying from less than 10 days to 100 or more days.
We suggest that island biogeographical models seem appropriate to recovery by secondary processes after level 3 and 4 disturbances,
where competition may be an important organizing factor, while models of numerical abundance and resource tracking are probably
of better use where community development is by primary succession (levels 1 and 2).
Development of predictive recovery models requires research that addresses a number of fundamental questions. These include
the role of hydrologic patterns on colonization dynamics, the role of nonaerial colonizers in recovery from level 1 disturbances,
and assessment of the impact of changes in the order of invasion by colonizers of varying energetic efficiencies. Finally,
we must be able to assemble these data and determine whether information that guides community organization at one level of
disturbance can provide insights into colonization dynamics at other levels. 相似文献
54.
本文依据生态学理论对海岛土地及土地系统生态功能进行了重新的认识,并探讨了海岛土地系统生态设计的依据、原则和模式.设计中强调以土地系统生态保护性功能为主体,以海岛土地系统高层次调合发展作为海岛建设的最终目标. 相似文献
55.
环厦门海域水色变化的多光谱多时相遥感分析 总被引:3,自引:0,他引:3
采用基于影像光谱信息建立的水质遥感模型对环厦门海域1989~2003年间的水色变化进行了分析.通过对水体及其所含物质的物理光学性质分析,水质遥感模型的建立可以不依赖于和卫星同步的水质采样数据建立水质遥感.这使得遥感对水色分析的应用更容易,而且还可以利用大量卫星存档数据来进行水质的历史变化分析.使用基于可见光和近红外波段反射率创建的模型研究了离水信号和水中物质(悬浮物和浮游植物)的关系.提出了一套可用于Landsat TM/ETM 和SPOT 5影像的水专题处理流程,并用于揭示所研究海域中悬浮物和叶绿素浓度的时空变化规律.研究表明,利用基于影像光谱的水质遥感模型,可以快速有效地揭示长时间范围内水色的时空变化.总的看来,环厦门海域的悬浮物浓度在所研究的时期内,有显著的增加,叶绿素的浓度在局部也有明显的升高.最明显的是,高悬浮物浓度的海域面积所占的比例从1989年的0.2%上升到2003年的10.2%.综合分析表明,九龙江河口所带来的巨量悬浮物是该海域最主要的陆源排海物和污染源,过度的水产养殖是另一个主要的污染因子. 相似文献
56.
One of the great mysteries of coral-reef fish ecology is how larvae locate the relatively rare patches of coral-reef habitat on which they settle. The present study aimed to estimate, by experiments in aquaria, the sensory modalities of coral-reef fish larvae for senses used in searching for their species settlement habitat. Larval recognition of settlement habitat can be based on the detection of conspecifics and/or of characteristics of coral habitat using visual, chemical and mechanical cues. For this study, larvae were captured with crest nets and were then introduced into experimental tanks that allowed testing of each type of cue separately (visual, chemical or mechanical cues). Among the 18 species studied, 13 chose their settlement habitat due to the presence of conspecifics and not based on the characteristics of coral habitat, and 5 species did not move toward their settlement habitat (e.g. Scorpaenodes parvipinnis, Apogon novemfasciatus). Among the different sensory cues tested, two species used the three types of cues (Parupeneus barberinus and Ctenochaetus striatus: visual, chemical and mechanical cues), six used two types (e.g. Myripristis pralinia: visual and chemical cues; Naso unicornis: visual and mechanical cues), and five used one type (e.g. Chrysiptera leucopoma: visual cues; Pomacentrus pavo: chemical cues). These results demonstrate that many coral-reef fish larvae could in practice use sensory cues for effective habitat selection at settlement, and have the ability to discriminate species-specific sensory cues.Communicated by J. Krause 相似文献
57.
大连长兴岛及毗邻海域环境质量评价 总被引:2,自引:0,他引:2
根据2002年7月大连市长兴岛生态建设研究现场调查资料,探讨了长兴岛及毗邻海域水质和沉积物要素分布特征,评价了海域环境质量和营养状况。结果表明,水质和沉积物中重金属含量在近岸呈上升趋势,其中,水质Hg、Zn、Pb最高量值分别超过一类标准的0.64、0.54、0.30倍,沉积物中Cu最高量值超一类标准的0.20倍。水质营养水平指数E为0.08,NQI为1.04,cN/cP为2.50。海域环境质量总体良好,介于清洁与较清洁级之间,岛西部环境质量优于北部及南部,海域处于贫营养状态。海岛陆源污染物是影响海域环境的主要因素。 相似文献
58.
河岸带湿地土壤溶解有机质(Dissolved organic matter,DOM)对陆源污染物的迁移和对河流水体富营养化进程均具有重要影响.本研究以典型河口冲积岛——崇明岛河岸带湿地DOM为研究对象,采用液相四级杆飞行时间质谱(Liquid chromatography quadrupole time-of-flight mass spectrometry,LC-Q-TOF-MS)技术分析河岸带湿地土壤DOM的分子组成特征,探究河岸带湿地DOM可能的主要来源.研究结果表明:LC-QTOF-MS技术成功地解析了复杂混合物DOM的分子组成特征,其中脂类化合物是崇明岛河岸带湿地土壤DOM的主要组分,占到28.87%~43.87%,其次为蛋白类物质和羰基类化合物,分别占到总DOM的17.46%~36.54%和19.13%~31.28%,最少的是脂肪酸类、糖类和氨基酸类物质,其三者之和仅为12%左右.同时,崇明岛河岸带湿地DOM分子主要来源于河岸带湿地植物光合生产和陆上区域农业面源径流、生活污水和工业废水的排放,其空间分布受小流域土地利用类型影响.研究结果为复杂混合物的分子组成解析和河岸带湿地管理提供一种新思路. 相似文献
59.
Jingying Mao Zhiming Chen Zhaoyu Mo Xiaoyang Yang Hong Li Yonglin Liu Huilin Liu Jiongli Huang Junchao Yang Hongjiao Li 《环境科学学报(英文版)》2018,30(10):64-74
A single particle aerosol mass spectrometer was deployed to measure the changes of single particle species and sizes during March 2015 in Weizhou Island of the Beibu Gulf, Guangxi province, South China. In this campaign, a total of 3,100,597 particles were sized, and 25.8%particles with both positive and negative mass spectrum were collected and 24.8%characterized in combination with the ART-2 a neural network algorithm. The distribution of sized particles was mainly in from 520 to 600 nm, and the diameters ranging from 340 to1000 nm accounted for above 90%. Eight types of particles were classified: Elemental Carbon containing(EC), Organic Carbon containing(OC), EC and OC combined containing particles,Na containing particles, K containing particles(K), Levoglucosan containing particles,mineral containing particles, and Heavy Metal containing particles(HM). EC, OC and K were the major containing particles, which accounted for 84.3% in the eight types particles. The relative ratio and size distribution of the three types were EC(48.1%, 620 nm), OC(12.7%,440 nm), and K(23.5%, 600 nm), respectively. The three types of particles were a bit increasing ratios compared with those in clean periods during haze pollution periods.Combined with the back-trajectory results from the Hysplit-4 model and local pollution sources revealed that the ambient air quality on the Weizhou Island may be influenced by biomass burning in the Indochina Peninsula(biomass burning in the Indochina Peninsula)from the transportation on higher level atmospheric layer and by mainland of south China located northeast of Weizhou Island on the ground. 相似文献
60.
Nickitas Georgas Srinivasan Rangarajan Kevin J. Farley Sarath Chandra K. Jagupilla 《Journal of the American Water Resources Association》2009,45(3):715-733
Abstract: The Generalized Watershed Loading Functions (GWLF) model and its ArcView interface (AVGWLF) were used to estimate and examine the components of the total nitrogen (TN) nonpoint source (NPS) load generated within New York and Connecticut (CT) watersheds surrounding Long Island Sound (LIS, the Sound). The majority of data used as model inputs were generally available from online sources, and the work involved an overall calibration to streamflow and TN data in accordance with generic guidelines recommended in the GWLF manual. The GWLF model performance for three calibration and two validation watersheds in CT was compared with results of a detailed model, Hydrological Simulation Program in Fortran, developed in a previous study. The results of the application illustrate the usefulness of the relatively simpler, less parameter‐intensive GWLF model in performing exploratory loading analysis in preparation for adaptive nutrient management in the LIS watersheds. The presented methodology is valuable for identification of priority watersheds for NPS pollution reduction and also for planning‐level evaluation of best management practices to achieve the desired reductions. It is estimated that ground‐water base flow may be the largest pathway for NPS TN to the Sound, contributing about 54% of the total NPS TN load, a finding with significant implications for LIS total maximum daily load reduction scenarios. In addition to ground water, septic systems are estimated to contribute about 17% of the total load, with the remaining TN load being mostly runoff from urban (17%), agricultural (5%), and low impact (e.g., forest) areas (6%). 相似文献