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1.
综合分析中国近海不同海域浮游植物的时空分布和季节变化特征研究,概述该海域浮游植物叶绿素和初级生产力研究。受复杂的物理环境场、生物地球化学作用等综合影响,不同海域Chl-a和初级生产力具有显著的时空变化特征:空间上,叶绿素浓度表现为近岸高离岸低、离岸海域随纬度增加呈升高趋势;时间上,大体呈现明显的季节变化特征,北部季节特征尤为明显,其中叶绿素浓度及生产力的季节最大值在南海出现在冬季,而在中国北部海域逐渐变化为春季。影响浮游植物生长的主要因素有营养盐、温度、光照、陆源输入、季风、环流、涡旋等,不同海域、不同季节浮游植物生长的限制因子有差异。另外,由于遥感数据的精度以及现场观测航次的频率较低和站位布置较为稀疏影响了上述机制的探讨,因而浮游植物生长的主要调控机制仍待进一步研究。 相似文献
2.
黄河三角洲是陆海交界地带,陆地海洋相互作用显著,泥沙所引起的岸滩演变、港口航道的淤积、水动力环境的改变等问题比较复杂。该文采用三维HEM-3D数值模型对黄河三角洲海域流场变化、盐度、悬浮泥沙浓度及海岸冲淤分布进行了潮流周期内的数值模拟分析。结果表明,黄河三角洲海域的悬浮泥沙浓度分布与潮流场变化和河口泥沙输入有密切的关系,在三角洲北部受五号桩外强潮流区的影响,近岸海底的泥沙发生明显的再悬浮,并在涨潮流向南输送,含沙量达1.5 g/L左右。在三角洲南部(现行河口区域和莱州湾区域),受现行河口入海泥沙扩散的影响显著。海域年冲淤分布,在北部废弃三角洲区域,由于海洋动力作用强烈,浅水冲刷,海底侵蚀显著,形成了明显呈沿岸展布的侵蚀中心,在侵蚀中心以外,侵蚀快速减弱。在现行河口区域,以淤积为主,在羽状流扩散的控制下,泥沙入海后向南输运,至莱州湾区域逐渐减弱。数值模拟的结果与卫星遥感解译的岸线变化基本一致,效果良好。 相似文献
3.
《广东海洋大学学报》2015,(3)
研究了琼东海域冬季(2012年12月)和夏季(2013年8月)表层水体营养盐结构特征和营养盐对浮游植物生长的限制情况。结果表明:2012年冬季,调查海域除了北部站位DIN、Si O32-浓度和nDIN/nP、nSi/nP比值较高之外,其余站位营养盐浓度和比值整体比较低且分布比较均匀,这是由于北部站位受到了具有高浓度DIN、Si O32-和低浓度PO43-的广东沿岸流的影响;2013年夏季,由于夏季河流径流量大,琼东近岸海域受到具有低浓度DIN、PO43-和高浓度Si O32-特征的河流影响,同时夏季近岸生物量增大和层化作用增强,因此DIN和PO43-浓度分布比较均匀,Si O32-浓度和nSi/nDIN、nSi/nP比值呈近岸高离岸低的分布特点。进一步分析该海域营养盐对浮游植物生长的可能限制因子发现,表层水体冬季呈现明显的硅限制,其限制因子几率为58.83%,夏季呈现氮-硅协同限制的可能性。由于生物利用、季节性的河径流量、广东沿岸流以及层化作用的影响,使得营养盐限制因子由冬季的硅限制转变为夏季的氮和硅共同限制。 相似文献
4.
【目的】分析珠江磨刀门河口浮游植物叶绿素a及其驱动因子的潮周期变化,并揭示叶绿素a的环境影响机制。【方法】基于珠江磨刀门河口2017年枯季(1月13-20日)水文水质多要素同步观测数据,采用主成分分析(PCA)和结构方程模型(SEM)确定浮游植物叶绿素a与多个环境因子的关系并量化各因子的驱动作用。【结果】磨刀门水道浮游植物叶绿素a浓度变化范围为0.77～10.92μg/L,口门处变化为0.70～9.01μg/L,磨刀门河口动力驱动下浮游植物叶绿素a的潮周期差异显著。盐度、含沙量和氮磷营养盐亦随潮汐涨落差异显著,而水温无明显潮周期变化。【结论】外海水团对氮营养盐的稀释混合作用强于磷营养盐,而悬浮泥沙对磷营养盐的吸附作用强于氮营养盐。与氮营养盐相比,溶解态磷相对不足,限制磨刀门河口浮游植物的生长。径流(营养盐、悬沙等为代表)、潮流(盐度为代表)对河口浮游植物的影响机制不同,其中氮磷营养盐和水温起着直接作用,而悬沙和盐度间接影响浮游植物叶绿素a的变化。 相似文献
5.
【目的】研究秋季雷州半岛海域东西部水体营养盐和叶绿素a(Chl-a)空间变化特征及其相互关系。【方法】根据2017年10月(秋季)的现场调查资料,分别采用镉铜柱还原-重氮偶氮法、重氮偶氮法和硅钼蓝法测定硝酸盐、亚硝酸盐、磷酸盐和硅酸盐,以及萃取荧光法测定Chl-a浓度,深入探讨雷州半岛Chl-a浓度空间变化的调控机制。【结果】2017年秋季,研究区域近岸Chl-a及营养盐浓度大致呈现近岸高离岸低的分布特点;雷州半岛东部海域与西部海域相比,Chl-a浓度、DIN、Si O32-,nDIN/nP比较高,而nSi/nDIN和PO43-在西部略高于东部;营养盐对浮游植物生长的可能限制因子分析结果,在雷州半岛东西部环境因子对Chl-a浓度的影响程度不同,其中盐度和亚硝酸盐是影响Chl-a浓度的主要因子。在浮游植物生长的限制因素方面,雷州半岛东部海域表现为明显的磷限制,西部海域表现为明显的氮限制。【结论】秋季调查海域营养盐和Chl-a结构变化主要受海域水文情况(河流径流,潮汐类型)和人类活动的影响。调查海域东部受到河流径流和不规则半日潮的影响,营养盐、Chl-a浓度以及营养盐比值(PO43-和nSi/nDIN除外)都比较高。西部海域由于河流径流量小、人类活动较少以及受到规则的全日潮的影响,营养盐、Chl-a浓度以及营养盐比值含量较低且分布较均匀。 相似文献
6.
刘荣高 《地球信息科学学报》2011,13(4):571-572
"物候学记录植物的生长荣枯,……等自然现象,从而了解随着时节推移的气候变化和这种变化对动植物的影响"(竺可桢)。植物的开花、落叶等物候现象的长期记录,既描绘了气候系统对生态系统的影响,同时也刻画了气候的变迁。物候学对全球变化、农林业等领域的意义重大,例如气候变化与植被适应性、城市热岛效应对生态系统的影响、气候波动对生态系统、农作物的播种和管理、植被碳固定的估算、全球物质与能量循环、全球碳循环等的影响。当今,全球气候变化已经成为全世界的热点话题,物候的研究日益受到关注。 相似文献
7.
太湖蓝藻水华遥感动态监测预警模型的建立 总被引：7，自引：0，他引：7
湖泊富营养化和蓝藻水华暴发是当前我国湖泊面临的最重要的环境问题之一。本文分析了内陆湖泊太湖蓝藻监测的主要问题。并详细阐述了蓝藻水华遥感动态监测预警模型的建立,即,采用生物光学模型与气象环境预警模型相结合的方式,辅以图形图像学的模块匹配验证,对蓝藻水华暴发前进行临界状态的灾害等级警示,理论上较单纯监测微囊藻叶绿素a浓度值来实现水华暴发预警更为准确。这样,提前采取相应的技术措施,减少蓝藻水华暴发带来的影响和损失。 相似文献
8.
斯里兰卡是海上丝绸之路沿线重要的节点国家,其周边海域生态环境变化与经济发展、休闲生活和食品安全密切相关。利用2002—2017年的MODIS遥感反演产品对斯里兰卡岛周边海域、关键节点港口科伦坡的生态环境参数年际变化规律分别进行分析和2003—2012年的MERIS遥感反射率产品对保克海峡进行水体类型时空分析,结论如下：① 研究区内光合作用有效辐射高值出现在马纳尔湾,海域沿岸浮游植物生物量相对较高,与海表温度负相关,外海浮游植物生物量极低,与透明度负相关。② 科伦坡港附近水温（海表温度）、海面光照强度（光合作用有效辐射）、水体清洁度（海水透明度）、海洋食物网基础的浮游植物生物量（叶绿素浓度）和浮游植物净初级生产力最大值分别出现在4月、3月、3月、8月、7月,致灾因素重点关注8月潜在的赤潮。③ 保克海峡浑浊带的源头是印度的卡里梅尔角,由高韦里河携带大量泥沙造成。这有助于了解和认识高时空变化的保克海峡及斯里兰卡周边海域在不同时间-空间的海洋生态环境。 相似文献
9.
目前水华已成为国内外一个重要的环境问题，单一的光学遥感方法难以实现精细化的水华预测。针对上述问题，本文以无人机多光谱影像、水质、水温及气象数据为数据源，首先通过像素匹配法（Matching Pixel-by-Pixel,MPP）反演水质参数及归一化植被指数（Normalized Difference Vegetation Index, NDVI）阈值法提取水华信息，然后基于地理加权回归（Geographically Weighted Regression, GWR）建立涵盖面积信息和位置信息的水华短时预测模型，并探讨了预测窗口尺寸对预测结果的影响。结果表明：(1)本文方法可以实现精细化的水华短时预测，在应用中对水华面积预测精度达到96.19%，在水华空间分布的预测上对水华和非水华的总体分类精度均大于0.97，生产者精度、Kappa系数均大于0.5；(2) MPP反演的总氮、总磷和溶解氧浓度与实测数据都有着较高的相关性，其决定系数R2分别达到0.89、0.85、0.89；(3)不同尺寸的预测窗口直接影响预测结果精度，相比8×8、12×12、14×14，选用10×10预测窗口得到的总体分类... 相似文献
10.
《广东海洋大学学报》2015,(3)
以北部湾1999年7月至2009年6月11年的Sea Wi FS卫星遥感颗粒无机碳度资料为基础,研究北部湾颗粒无机碳浓度的时空分布特征,并初步探讨其可能的海洋动力调控机制。结果表明:在季节变化上,整个冬季北部湾颗粒无机碳浓度普遍较高,表现出季节平均最大值(0.012 mol·m-3),春季普遍较低(0.004 mol·m-3),表现出全年最低水平;不同区域的最高水平出现的季节却有所不同:北部湾北部沿岸区域颗粒无机碳浓度在秋季较高,海南岛西部大部分海域在冬季较高,北部湾西北部沿岸则在夏季较高;在空间分布上,近岸海区的颗粒无机碳浓度明显高于海湾中央区域,北部湾北部海域普遍高于南部海域,东部海域高于西部海域。综合相关分析表明,北部湾颗粒无机碳浓度的这一时空分布特征主要同季风的强弱及风向有关,同时也可能与海表温度、流场(如沿岸上升流等)及陆地径流量等有关。 相似文献
11.
Monitoring algal blooms by optical remote sensing is limited by cloud cover.In this study,synthetic aperture radar(SAR) was deployed with the aim of monitoring cyanobacteria-dominant algal blooms in Taihu Lake in cloudy weather.The study shows that dark regions in the SAR images caused by cyanobacterial blooms damped the microwave backscatter of the lake surface and were consistent with the regions of algal blooms in quasi-synchronous optical images,confirming the applicability of SAR for detection of surface blooms.Low backscatter may also be associated with other factors such as low wind speeds,resulting in interference when monitoring algal blooms using SAR data alone.After feature extraction and selection,the dark regions were classified by the support vector machine method with an overall accuracy of 67.74%.SAR can provide a reference point for monitoring cyanobacterial blooms in the lake,particularly when weather is not suitable for optical remote sensing.Multi-polarization and multi-band SAR can be considered for use in the future to obtain more accurate information regarding algal blooms from SAR data. 相似文献
12.
Eutrophication has become a serious concern in many lakes, resulting in cyanobacterial blooms. However, the mechanism and pathways of cyanobacteria decline are less understood. To identify and define the growth and decline of Microcystis blooms in Taihu Lake of China, and to illuminate the destination of surface floating blooms, we investigated the biomass distribution and variations in colony size, morphology, and floating velocity from October 2008 to September 2009. The results showed that the Microcystis bloom declined in response to biomass decrease, colony disaggregation, buoyancy reduction, and increased phytoplankton biodiversity, and these indicative parameters could be applied for recognition of the development phases of the bloom. Three major decline pathways were proposed to describe the bloom decline process, colony disaggregation (Pathway Ⅰ), colony settlement (Pathway Ⅱ), and cell lysis in colonies (Pathway Ⅲ). We proposed a strategy to define the occurrence and decline of Microcystis blooms, to evaluate the survival state under different stress conditions, and to indicate the efficiency of controlling countermeasures against algal blooms. 相似文献
13.
1 INTRODUCTION Rainfall chemical composition is mainly re- sulted from inner-cloud nucleation and under-cloud washing. The aerosol in cloud features regional scales. The concentration and chemical composition of under-cloud aerosol reflect in overall the … 相似文献
14.
ＩＮＴＲＯＤＵＣＴＩＯＮＮａｎｄＰｉｎｐｕｔｔｅｄｉｎｔｏＪｉａｏｚｈｏｕＢａｙｂｙｒｉｖｅｒｓａｎｄｂｙｓｅｗａｇｅｅｆｆｌｕｅｎｔｓｏｆｃｉｔｉｅｓ ,ｈａｖｅｍａｄｅｔｈｅＢａｙｂｅｃｏｍｅｍｏｒｅａｎｄｍｏｒｅｅｕｔｒｏｐｈｉｃｄａｙｂｙｄａｙ .Ｓｈｅｎ ( 1994)ｔｈｏｕｇｈｔｔｈａｔｐｈｙｔｏｐｌａｎｋｔｏｎｇｒｏｗｔｈｗａｓｌｉｍｉｔｅｄｂｙｔｈｅｃｈａｎｇｅｆｒｏｍｎｉｔｒｏｇｅｎｔｏｐｈｏｓｐｈｏｒｏｕｓ ;ａｎｄｔｈａｔｔｈｅｓｉｌｉｃａｔｅｃｏｎｃｅｎｔｒａｔｉｏｎｉｎＪｉａｏｚｈ… 相似文献
15.
Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994 (12 seasonal investigations) provided
by the Ecological Station of Jiaozhou Bay revealed the characteristic spatiotemporal variation of the ambient concentration
Si∶DIN and Si∶16P ratios and the seasonal variation of Jiaozhou Bay Si∶DIN and Si∶16P ratios showing that the Si∶DIN ratios
were <1 throughout the year in Jiaozhou Bay; and that the Si∶16P ratios were <1 throughout Jiaozhou Bay in spring, autumn
and winter. The results proved that silicate limited phytoplankton growth in spring, autumn and winter in Jiaozhou Bay. Analysis
of the Si∶DIN and Si∶P ratios showed that the nutrient Si has been limiting the growth of phytoplankton throughout the year
in some Jiaozhou Bay waters; and that the silicate deficiency changed the phytoplankton assemblage structure.
Analysis of discontinuous 1962 to 1998 nutrient data showed that there was no N or P limitation of phytoplankton growth in
that period. The authors consider that the annual cyclic change of silicate limits phytoplankton growth in spring, autumn
and winter every year in Jiaozhou Bay; and that in many Jiaozhou Bay waters where the phytoplankton as the predominant species
need a great amount of silicate, analysis of the nutrients N or P limitation of phytoplankton growth relying only on the N
and P nutrients and DIN∶P ratio could yield inaccurate conclusions. The results obtained by applying the rules of absolute
and relative limitation fully support this view.
The authors consider that the main function of nutrient silicon is to regulate and control the mechanism of the phytoplankton
growth process in the ecological system in estuaries, bays and the sea.
The authors consider that according to the evolution theory of Darwin, continuous environmental pressure gradually changes
the phytoplankton assemblage's structure and the physiology of diatoms. Diatoms requiring a great deal of silicon either constantly
decrease or reduce their requirement for silicon. This will cause a series of huge changes in the ecosystem so that the whole
ecosystem requires continuous renewal, change and balancing. Human beings have to reduce marine pollution and enhance the
capacity of continental sources to transport silicon to sustain the continuity and stability in the marine ecosystem.
This study was funded by the NSFC (No. 40036010) and subsidized by Special Funds from the National Key Basic Research Program
of P. R. China (G199990437), the Postdoctoral Foundation of Ocean University of Qingdao, the Director's Foundation of the
Beihai Monitoring Center of the State Oceanic Administration and the Foundation of Shanghai Fisheries University. 相似文献
16.
Study on Optical Properties of Unpigmented Suspended Particles,Yellow Substance and Phytoplankton Algae in Taihu Lake 总被引：1，自引：0，他引：1
The optical properties of a waterbody are subjects of research on limnological hydrooptics. The optical properties of, and parameterization methods for, three impurities in Taihu Lake, namely unpigmented suspensions, yellow substance and phytoplankton algae, are analyzed in detail in this paper dealing with the optical types of Taihu Lake waters both in winter and in summer. The results showed that : 1 ) The optical parameters of suspended particles can be calculated by the application of Mie Theory; 2) The absorption of yellow substance decreases exponentially with increasing wavelength, with the mean value of decreasing rate being about 0.014 nm^-1 ; 3) Taihu Lake waters appeared to be of type PY in winter, with suspended particles and yellow substance being the dominant light absorbers, and type CPY in summer, with suspended particles, yellow substance and phytoplankton algae being the dominant light absorbers; 4) In winter or summer, unpigmented suspension has the main effect on the scattering property of Taihu Lake waters. 相似文献
17.
Food web structures are well known to vary widely among ecosystems. Moreover, many food web studies of lakes have generally attempted to characterize the overall food web structure and have largely ignored internal spatial and environmental variations. In this study, we hypothesize that there is a high degree of spatial heterogeneity within an ecosystem and such heterogeneity may lead to strong variations in environmental conditions and resource availability, in turn resulting in dif ferent trophic pathways. Stable carbon and nitrogen isotopes were employed for the whole food web to describe the structure of the food web in different sub-basins within Taihu Lake. This lake is a large eutrophic freshwater lake that has been intensively managed and highly influenced by human activities for more than 50 years. The results show significant isotopic dif ferences between basins with dif ferent environmental characteristics. Such differences likely result from isotopic baseline dif ferences combining with a shift in food web structure. Both are related to local spatial heterogeneity in nutrient loading in waters. Such variation should be explicitly considered in future food web studies and ecosystem-based management in this lake ecosystem. 相似文献
18.
Alexey P. Kuklin Gazhit Ts. Tsybekmitova Evgenia P. Gorlacheva Balzhit B. Bazarova Alexey V. Afonin 《中国海洋湖沼学报》2016,34(3):507-516
Present-day conditions of the Lake Kenon ecosystem are determined by a combination of natural and anthropogenic factors.We have estimated the effects of a complex of factors on the condition of the abiotic environment and on specific biological components in the lake ecosystem.Change in biogenic load has caused an increase in the role of phytoplankton in the general balance of organic matter during the high-water period.Charophytes are the main dominants of bottom vegetation.Anthropogenic load has caused a decrease in both fish species and fish capacity.The lake application as a water reservoir-cooler has influenced the average annual water mineralization(from 420 mg/L to 530.0 mg/L with a maximum 654 mg/L in 1993) and fluctuations in its hydrochemical composition.The present composition of the lake is sulfate-hydrocarbonate-chloride calcium-sodic-magnesium in character.SO 4 – content is twice as much as the maximum permissible concentration in fishery waters.Water drainage from an ash disposal area to the lake has caused an increase in chemical-element concentrations including the heavy metals.Hg concentration in Perca fluviatilis muscles is 0.5 μg/g dry wt.Thus,understanding directions in the ecosystem of the water reservoir-cooler under changing hydrological conditions will let us forecast the consequences of new combined heat and power plant operation. 相似文献
19.
The Taihu Lake,a large shallow lake in the floodplain of the Changjiang(Yangtze) River in the eastern China,is faced with challenging ecological problems resulting from eutrophication,which has affected the regional freshwater supply of a large population.Although efforts have been made to assess the nutrient evolution histories in the northern bays,little is known regarding nutrient histories in different parts across the entire lake basin.In this paper,we present nutrient histories for different parts of the lake based on chironomid transfer functions applied to four short cores obtained from the northern,western and eastern regions of the lake.The chironomid-inferred total phosphorus(CI-TP) concentrations were compared with the phosphorus concentrations obtained by using instrumental and sedimentary data.The results suggest that trophic evolution histories were asynchronous throughout the lake during the past decades in response to different ecological regimes controlled by the nutrient input,wind direction and shoreline topography.The restoration of aquatic plants may be an effective option for the management of lake rehabilitation to ′natural′ conditions.Given the multiple factors controlling the biotic communities in such a large and complex lake,combined analyses among the multi-proxies encountered in the sediments are necessary for comprehensive insight into paleolimnological studies.The spatial heterogeneity in the ecological trajectories within this complicated ecosystem suggests that different management practices should be undertaken for specific lake zones in the Taihu Lake. 相似文献