共查询到19条相似文献，搜索用时 109 毫秒
1.
Mohamed O.Soliman Waleed B.Suleiman Mohamed M.Roushdy Eman N.Elbatrawy Ahmed M.Gad 《海洋学报(英文版)》2022,41(3):86-93
Marine microorganisms were considered to be important sources of marine bioactive compounds. The major objective of the study was to isolate and characterize bacteria with antimicrobial activities from the various marine environment of Egypt. In this respect, thirty-five bacterial isolates were recovered from sediment samples collected from different spots along the Egyptian Red Sea coastline and Alexandria coastline during the summer season of 2017 and 2018. According to the morphological, phys... 相似文献
2.
3.
The distribution and chemical properties of chromophoric dissolved organic matter (CDOM) in the Jiaozhou Bay, China were examined during four cruises in 2010-2011. The influence of freshwater and industrial and municipal sewage along the eastern coast of the bay was clearly evident as CDOM levels (defined as a 305 ), and dissolved organic carbon (DOC) concentrations were well correlated with salinity during all the cruises. Moreover, DOC concentrations were significantly correlated with chlorophyll a concentrations in the surface microlayer as well as in the subsurface water. The concentrations of DOC and CDOM displayed a gradually decreasing trend from the northwestern and eastern coast to the central bay, and the values and gradients of their concentrations on the eastern coast were generally higher than those on the western coast. In addition, CDOM and DOC levels were generally higher in the surface microlayer than in the subsurface water. In comparison with DOC, CDOM exhibited a greater extent of enrichment in the microlayer in each cruise, with average enrichment factor (E F ) values of 1.38 and 1.84, respectively. Four fluorescent components were identified from the surface microlayer and subsurface water samples and could be distinguished as peak A, peak T, peak B and peak M. For all the cruises, peak A levels were higher in the surface microlayer than in the subsurface water. This pattern of variation might be attributed to the terrestrial input. 相似文献
4.
In the present paper, the Holocene sea level changes and coastline shifts in Zhejiang, China are discussed, based on the ancient coastline evidence related with sea level changes and 21 14C dat-ings of shell, peat or mud and wood samples along the Zhejiang coast. The development of Zhejiang coastline during the Holocene period can be divided into four stages. A lot of data of historical period and modern times have shown that tracing coastline shifts back to its source, we have to consider tremendous effects of man's activities besides natural factors, such as elevation and subsidence of the earth crust, sea level changes, supply of sediment, and littoral hydrodynamics. 相似文献
5.
Jiangsu has the most abundant tidal flat resources among China's coastal provinces.To ease the conflict between the growing population and shrinking usable land and to promote regional sustainable development,large-scale coastal reclamation development activities have been performed in Jiangsu Province since 1949.The present study has integrated multi-source remote sensing images during 1974 to 2012 by using a Multi-point Fast Marching Method(MFMM) to extract the Jiangsu coastal reclamation areas for different time periods.The temporal and spatial patterns of the extent and elevation of the reclamation areas were analysed in order to determine the unused potential for future reclamation.It will provide information necessary to support the development and construction of tidal flats in Jiangsu.Results show that:(1) the reclaimed tidal flats along the Jiangsu coast cover more than 19.86×104 hm2,of which 13.97×104 hm2 is located in Yancheng,4.84×104 hm2 in Nantong,and 1.05×104 hm2 in Lianyungang;(2) the average elevation of the reclaimed Jiangsu tidal flats has gradually decreased over the last 40 years,while those in Dongtai and Rudong have showed particularly accelerated decrease since the 1990s;and(3) in 2012,very few unused tidal flats two meters above the sea level are left along the Jiangsu coast,and mainly concentrated in Yancheng.As there are still reserving some coastal land resources between 0-2 m,providing us with a potential for future development.All of these findings may be useful for researchers and local authorities for the development and utilization of tidal flat resources in Jiangsu. 相似文献
6.
ZHU Xiaohua 《中国海洋工程》2000,14(4):533-540
According to the fractal theory,the spatial fractal character of coastline is preliminarily dis-cussed on the basis of GIS in this paper.Two aspects are considered:one is the length demarcation ofcoastline with different scales,and the other is the confirmation of existence of the fractal character on dif-ferent boundaries of tidal flats.Finally,some significant conclusions are drawn:(1)The coastline ofJiangsu Province has the fractal character and its dimension is 1.0696.(2)It conforms to the exponentialcorrelation between different lengths(L)of coastline and scales(k).It conforms to the formula lgL(k)=-1.029lgk+2.9544 in the continental coastline of Jiangsu province.(3)Different boundaries of a tidal flathave fractal characters,and different fractal dimensions indicate different comparative intensities of ero-sion and deposition on the tidal flat.(4)The reciprocity between land and sea may affect the value offractal dimension of a coastline,just as the lithology,substantial constituent and geological s 相似文献
7.
The exposed area of intertidal zone varies with tidal water level changes. If intercomparisons of
satellite images are adopted as a method to determine geomorphological changes of the intertidal
zone in response to accretion or erosion processes, then the e?ect of water level variations must be
evaluated. In this study, two Landsat TM images overpassing the central Jiangsu coastal waters on
2 January and 7 March 2002, respectively, were treated by the changing detection analysis using
Image Di?erencing and Post-classiˉcation Comparison. The simultaneous tide level data from four
tide gauge stations along the coast were used for displaying the spatial variations of water levels
and determining the elevations of waterlines. The results show that the spatial variations of water
levels are highly signiˉcant in the central Jiangsu coastal waters. The huge di?erences of tidal land
exposure patterns between the two imaging times are related mainly to the spatial variations of
tidal water levels, which are controlled by the di?erences in tidal phases for di?erent imaging times
and the spatial variations of water level over the study area at each imaging time. Under complex
tidal conditions, e.g., those of the central Jiangsu coastal waters, the tide-surge model should be
used to eliminate e?ectively the e?ects of water level variations on remote sensing interpretation of
geomorphological changes in the intertidal zone. 相似文献
8.
Jiangsu has the most abundant tidal flat resources among China’s coastal provinces. To ease the conflict between the growing population and shrinking usable land and to promote regional sustainable development, large-scale coastal reclamation development activities have been performed in Jiangsu Province since 1949. The present study has integrated multi-source remote sensing images during 1974 to 2012 by using a Multi-point Fast Marching Method (MFMM) to extract the Jiangsu coastal reclamation areas for different time periods. The temporal and spatial patterns of the extent and elevation of the reclamation areas were analysed in order to determine the unused potential for future reclamation. It will provide information necessary to support the development and construction of tidal flats in Jiangsu. Results show that: (1) the reclaimed tidal flats along the Jiangsu coast cover more than 19.86×104 hm2, of which 13.97×104 hm2 is located in Yancheng, 4.84×104 hm2 in Nantong, and 1.05×104 hm2 in Lianyungang; (2) the average elevation of the reclaimed Jiangsu tidal flats has gradually decreased over the last 40 years, while those in Dongtai and Rudong have showed particularly accelerated decrease since the 1990s; and (3) in 2012, very few unused tidal flats two meters above the sea level are left along the Jiangsu coast, and mainly concentrated in Yancheng. As there are still reserving some coastal land resources between 0?2 m, providing us with a potential for future development. All of these findings may be useful for researchers and local authorities for the development and utilization of tidal flat resources in Jiangsu. 相似文献
9.
The community structure of zooplankton has been conducted in the Lembeh Strait in Bitung and Wori Beach in Manado, North Sulawesi in October 2015. Sampling of this research was conducted in 22 sampling sites along the strait. Zooplankton samples were collected from 22 stations, by NORPAC 300 μm net that was vertically hauled from maximum 10 m depth up to the surface water. The samples were poured into the bottle with formalin of 4%as preservative. The results showed that there were 43 taxa of zooplankton. The abundance of zooplankton was between 21.216–4 193.776 ind./m~3. The dominant taxa were copepod, especially Calanoida. The composition of zooplankton was relatively similar in all stations. We showed the abundance, dominance, composition and distribution of zooplankton at this research. More extensive studies concerning zooplankton is required to understand zooplankton biodiversity as a whole especially on the geographical and spatial distribution to describe population and community dynamic in the Lembeh Strait and Wori Beach. 相似文献
10.
The invasions of the alien species such as Spartina alterniflora along the northern Jiangsu coastlines have posed a threat to biodiversity and the ecosystem function.Yet,limited attention has been given to their potential influence on greenhouse gas(GHG) emissions,including the diurnal variations of GHG fluxes that are fundamental in estimating the carbon and nitrogen budget.In this study,we examined the diurnal variation in fluxes of carbon dioxide(CO_2),methane(CH_4),and nitrous oxide(N2O) from a S.alterniflora intertidal flat in June,October,and December of 2013 and April of 2014 representing the summer,autumn,winter,and spring seasons,respectively.We found that the average CH_4 fluxes on the diurnal scale were positive during the growing season while negative otherwise.The tidal flat of S.alterniflora acted as a source of CH_4 in summer(June) and a combination of source and sink in other seasons.We observed higher diurnal variations in the CO_2 and N_2O fluxes during the growing season(1 536.5 mg CO_2 m~(–2) h~(–1) and 25.6 μg N_2O m~(–2) h~(–1)) compared with those measured in the non-growing season(379.1 mg CO_2 m~(–2) h~(–1) and 16.5 μg N_2O m~(–2) h~(–1)).The mean fluxes of CH_4 were higher at night than that in the daytime during all the seasons but October.The diurnal variation in the fluxes of CO_2 in June and N_2O in December fluctuated more than that in October and April.However,two peak curves in October and April were observed for the diurnal changes in CO_2 and N_2O fluxes(prominent peaks were found in the morning of October and in the afternoon of April,respectively).The highest diurnal variation in the N_2O fluxes took place at 15:00(86.4 μg N_2O m~(–2) h~(–1)) in June with an unimodal distribution.Water logging in October increased the emission of CO_2(especially at nighttime),yet decreased N_2O and CH_4 emissions to a different degree on the daily scale because of the restrained diffusion rates of the gases.The seasonal and diurnal variations of CH_4 and CO_2 fluxes did not correlate to the air and soil temperatures,whereas the seasonal and diurnal variation of the fluxes of N_2O in June exhibited a significant correlation with air temperature.When N_2O and CH_4 fluxes were converted to CO_2-e equivalents,the emissions of N_2O had a remarkable potential to impact the global warming.The mean daily flux(MF) and total daily flux(TDF) were higher in the growing season,nevertheless,the MF and TDF of CO_2 were higher in October and those of CH_4 and N_2O were higher in June.In spite of the difference in the optimal sampling times throughout the observation period,our results obtained have implications for sampling and scaling strategies in estimating the GHG fluxes in coastal saline wetlands. 相似文献
11.
麻痹性贝类毒素（paralytic shellfish toxins,PSTs）能够导致贝类、鱼类等海洋生物染毒或死亡,危害海洋生态安全及人类健康。其中,贻贝具有强蓄积性特点,在国外可作为PSTs的指示性生物。近年来,我国因食用贻贝造成多起PSTs中毒事件成为安全关注重点,因此急需弄清其风险形成机理。本文通过综述我国近海贻贝等贝类中PSTs的风险程度、贻贝对不同产毒藻来源的PSTs的蓄积作用,分析环境因子对于蓄积代谢的影响,深入挖掘贻贝蓄积代谢特异性。进而聚焦贻贝代谢阶段的表达调控过程、影响因素、转化作用及方式等。未来应侧重于摸清我国目标区域贻贝等海洋贝类中PSTs基础风险规律和变化过程,并据此建立区域性PSTs风险防控技术,提高我国贻贝中PSTs风险的主动防控能力,对于保障消费者健康和海洋生态安全具有积极意义。 相似文献
12.
全新世苏北沿海岸线冲淤动态研究 总被引：2，自引：0，他引：2
探讨了 1 0kaB .P .以来苏北海岸线的动态演变过程 ,结果表明 :全新世本区曾遭受海侵。 6kaB .P .前 ,苏北海岸线位于西冈一线。 6kaB .P .至唐宋时期 ;海岸线变动较小 ,古砂堤成组出现 ,东冈代表了这个时期的海岸线 ,1 1 2 8- 1 85 5年 ,黄河夺淮 ,海岸线东迁迅速 ,古砂堤不够发育 相似文献
13.
文章利用卫星遥感解译、潮汐数值模拟、GIS空间拓扑分析等技术手段,对水边线进行水位订正,推算出2019年度江苏沿海的遥感海岸线,对江苏省海岸侵蚀现状进行了遥感监测与评估。研究结果表明:2019年江苏省共有侵蚀岸线长58.55 km,占全省大陆海岸线的7.39%。废黄河三角洲侵蚀型海岸的侵蚀岸段平均年侵蚀后退 59.24 m,主要表现为盐养围堤的冲刷水毁;辐射沙洲北翼淤长型海岸的侵蚀岸段年平均侵蚀后退152.28 m,表现为潮间带上部坡度变缓,海岸线持续内移。全省海岸带侵蚀总面积为 7.244 8 hm2,强侵蚀岸段主要分布在南八滩闸北侧,新洋河口两侧以及斗龙港南侧区域。文章同时结合江苏海域动态监管工作经验,提出了5点海岸侵蚀灾害防治对策:①加强天-空-地一体化多手段联合监测,精确监控海岸侵蚀灾害发生范围与程度,了解海岸侵蚀强度与等级;②联合多平台海洋观测,深入开展致灾因素分析,了解海岸侵蚀灾害的发展与变化趋势,逐步完善灾害预警机制;③根据不同的海岸类型与海岸侵蚀特征,有效开展多策略的海岸防护整治,减少海岸侵蚀灾害损失;④加快海岸带保护修复,明确海岸带开发活动的适宜空间与适宜程度,优化海岸带空间布局;⑤强化海岸责任管理,明确监管职责。 相似文献
14.
江苏岸外条子泥二分水滩脊的沉积特征 总被引：3，自引：1，他引：3
2000年1月16日在江苏岸外条子泥沙洲二分水滩脊选取三条断面，进行底质沉积物采样及滩面高程测量。共采集样品27个，对其用激光粒度仪进行粒度分析，发现沉积物的粒度参数、粒度组分及其分布均具有一定的变化规律，且与滩面高程变化具有很好的相关性。 相似文献
15.
16.
海南岛沿岸海域砗磲资源调查及保护前景展望 总被引：1，自引：0，他引：1
砗磲是珊瑚礁海域的重要贝类之一,对维护珊瑚礁生态系统平衡起着重要作用。然而,近年来海洋的大力开发和利用给我国沿海砗磲资源造成严重威胁。本研究通过截线样带法对海南岛沿岸海域砗磲的种类和分布进行实地调查,结果表明,海南岛沿岸海域砗磲覆盖度呈现南北差异,东南沿岸海域砗磲覆盖度明显高于西北沿岸海域,这种差异可能是由自然因素和人为因素共同造成。调查海域共发现3种砗磲:诺亚砗磲(Tridacna noae)最多,占砗磲样品总数的58.6%;其次是番红砗磲(T. crocea),占34.3%;鳞砗磲(T. squamosa)最少,仅占7.1%。海洋管理部门应该加强对砗磲多样性的保护力度,合理开发和可持续利用并重,从而有效保护砗磲、珊瑚礁乃至海洋生态系统。 相似文献
17.
苏北全新世海进与古砂堤研究 总被引：14，自引：0，他引：14
本文探讨了苏北全新世以来的海进与古砂堤的演变地过程。结果表明，全新世以来，苏北地区曾有海进，大约距今７ｋａ左右，海进达到了高峰，里下河地区成为一片浅 海。此后，海面相对稳定，沿岸堆积作用显著，出现了西冈，中冈，东冈，新冈等古砂堤群，其成为苏北海岸变迁的重要标志。 相似文献
18.
苏北废黄河三角洲海岸时空演变遥感分析 总被引：4，自引：0，他引：4
基于遥感与地理信息系统技术,使用苏北废黄河三角洲海岸地区1978,1987和2000年的Landsat卫星遥感数据,选取岸线指标与波段,提取岸线信息,生成1978-1987年和1987-2000年海岸土地增减时空变化分布图,建立岸线变化距离及增速衡量指标,定量分析了废黄河三角洲海岸面积变化特征,以及灌河口-中山河口、中山河口-扁担港口和扁担港口-双洋河口以南岸段的时空变化格局与分布特征.研究结果表明,废黄河三角洲海岸的自然侵蚀速率呈减小趋势,但侵蚀作用仍在继续.侵蚀强度以废黄河口地区为中心,向南北两侧逐渐减弱.人工保滩护岸措施在一定程度上影响着自然侵蚀格局.其内部各岸段分别呈现缓蚀、侵蚀和基本侵淤平衡的变化格局. 相似文献
19.
为探究在自然环境中虾夷扇贝Patinopecten yessoensis体内麻痹性贝毒(PSTs)的净化过程,从黄海北部大窑湾海域采集了受PSTs污染的虾夷扇贝,将其转移至黄海的棋盘磨水域,该水域未曾有PSTs污染的报道。本研究采用高效液相色谱-荧光检测法(HPLC-FLD)检测30天净化过程中虾夷扇贝体内PSTs的组分和水平。研究结果发现,在第9天,虾夷扇贝软体中的PSTs的含量下降到一个相对较低的水平。而且,初期扇贝体内PSTs的净化率高于后期。扇贝各组织器官中PSTs含量分析发现,消化腺中的PSTs含量最高,这对于人类健康和扇贝养殖具有重要的意义。在本研究中还发现,虾夷扇贝的死亡率与PSTs的水平有一定的关系。 相似文献