珠江口外表层沉积物底栖有孔虫组合及其与环境的关系     

李涛  向荣  李团结 《热带海洋学报》2011,(4)

对珠江口外CJ14区块250个站位的表层沉积物进行底栖有孔虫分析,共发现底栖有孔虫118种,其中玻璃壳质80种,瓷质壳质21种,胶结壳质17种。有孔虫丰度基本随水深变深而增大。为研究底栖有孔虫分布与沉积环境之间的关系,对底栖有孔虫含量进行Q型因子分析,并选取前4个主因子,分别对应4个有孔虫组合。它们总共解释了总方差的86.2%,基本上反映了沉积物中有孔虫的群落结构。研究表明,水深和盐度是影响珠江口表层沉积物中有孔虫组合分布的控制因素,其他影响因素主要包括沉积物类型、水动力条件和沉积速率。水动力条件主要影响有孔虫的含量;沉积速率主要影响有孔虫的丰度。  相似文献   

伶仃洋表层沉积物特征及其泥沙运移趋势     

肖志建  李团结  廖世智 《热带海洋学报》2011,(4)

根据伶仃洋表层沉积物的粒度分析资料,探讨表层沉积物的特征,并在此基础上应用Gao-Collins粒径趋势分析方法(GSTA模型)分析了伶仃洋表层沉积物的泥沙净输运趋势。结果表明,伶仃洋表层沉积物共有6种类型,其中以黏土质粉砂分布最广泛。受径流、潮流、波浪和陆架水入侵等多种动力作用,伶仃洋表层沉积物颗粒在北面最粗,南面次之,中间最细,东面略粗,西面略细;分选由中部向东、西两岸逐渐变好,但总体分选差;不同级配的泥沙分布和沉积特征存在差异。伶仃洋泥沙运移规律较复杂,泥沙呈现出向西南输运的总趋势;内伶仃洋四周泥沙受各种力作用,呈现出顺时针方向的环流运移,中心区域为最大浑浊带,泥沙以垂直落淤为主。淇澳岛以南至澳门半岛以东海域受粉砂和黏土向西扩散影响,泥沙向西运移。大屿海峡及外伶仃岛附近海域为高盐水入侵通道,泥沙向西北运移。  相似文献   

珠江口滨海湿地退化现状、原因及保护对策   总被引：1，自引：0，他引：1  

李团结  马玉  王迪  王爱军  周英 《热带海洋学报》2011,(4)

2007年和2008年秋季对珠江口滨海湿地进行了环境现状综合调查,结果表明,珠江口滨海湿地退化主要表现在4个方面:天然湿地面积减少、湿地生产力不断下降、湿地环境状况持续恶化和湿地景观破碎化。珠江口滨海湿地退化的原因主要为滩涂开发与围填海、污染物排放、养殖污染、海平面上升、过度捕捞、海砂开采和港口码头建设以及水土资源开发等因素。滨海湿地保护与利用对策主要有:制定有关滨海湿地保护的法律法规和湿地保护与利用规划;加强人才队伍建设和滨海湿地有关技术研究;建立滨海湿地动态监测体系;加大滨海湿地保护区建设的力度;加强宣传和教育。  相似文献   

长江口邻近海域溶解态铝的分布及季节变化   总被引：2，自引：0，他引：2  

闫丽  任景玲  罗建  吴莹  周锋  郝锵  刘素美 《中国海洋大学学报(自然科学版)》2011,(Z1):259-266

基于2006年6、8、10月对长江口邻近海域的大面调查资料,分析了溶解态Al的分布及季节变化,讨论了水团混合、悬浮颗粒物及浮游植物水华对溶解态铝分布的影响。结果表明,3个航次溶解态铝的水平分布规律相似,都是近岸浓度最高,随着离岸距离的增加浓度降低,6、8、10月溶解态Al的平均浓度分别为(119±77)、(109±80)和(138±73)nmol/L,统计结果表明该海域的溶解态铝具有明显的季节变化。影响溶解态铝分布的主要因素有水团混合、底沉积物的再悬浮以及浮游植物的调节作用。  相似文献   

Effect of reclamation time and land use on soil properties in Changjiang River Estuary,China   总被引：4，自引：1，他引：3  

ülo MANDER 《中国地理科学(英文版)》2011,21(4):403-416

The objective of this study is to analyze soil physical and chemical properties,soil comprehensive functions and impact factors after different years of reclamation.Based on the survey data taken from 216 soil sampling points in the Fengxian Reclamation Area of the Changjiang (Yangtze) River Estuary,China in April 2009 and remotely sensed TM data in 2006,while by virtue of multivariate analysis of variance (MANOVA),geo-statistical analysis (GA),prin-cipal component analysis (PCA) and canonical correspondence analysis (CCA),it was concluded that:1) With the in-crease in reclamation time,soil moisture,soil salinity,soil electric conductivity and soil particle size tended to decline,yet soil organic matter tended to increase.Soil available phosphorous tended to increase in the early reclamation period,yet it tended to decline after about 49 years of reclamation.Soil nitrate nitrogen,soil ammonia nitrogen and pH changed slightly in different reclamation years.Soil physical and chemical properties reached a steady state after about 30 years of reclamation.2) According to the results of PCA analysis,the weighted value (0.97 in total) that represents soil nutrient factors (soil nitrate nitrogen,soil organic matter,soil available phosphorous,soil ammonia nitrogen,pH and soil particle size) were higher than the weighted value (0.48 in total) of soil limiting factors (soil salinity,soil elec-tric conductivity and soil moisture).The higher the F value is,the better the soil quality is.3) Different land use types play different roles in the soil function maturity process,with farmlands providing the best contribution.4) Soil physi-cal and chemical properties in the reclamation area were mainly influenced by reclamation time,and then by land use types.The correlation (0.1905) of the composite index of soil function (F) with reclamation time was greater than that with land use types (-0.1161).  相似文献   

Perceptions of Climate Change and Adaptation Responses in a Local Community: the Barwon Estuary Complex,Victoria     

Jaclyne Scally 《The Australian geographer》2011,42(4):387-401

The climate change focus in Australia has shifted from mitigation to adaptation with an emphasis on place-specific case studies. The Barwon Estuary Complex (BEC) on the Bellarine Peninsula, central Victoria, was the focus of this place-specific study in which 37 local stakeholders were consulted through a series of semi-structured interviews on the impacts of climate change on their coastal community. Overall there was uniformity in stakeholder perceptions of the climate change impacts and vulnerabilities pertaining to the BEC. In contrast, discussion on adaptation drew a diversity of responses. While 53 per cent of stakeholders indicated a need to limit the use of hard structures, and rather plan around a changing estuarine environment, opinion amongst the community group was divided. Some believed ‘retreat is the only option’ whilst others felt ‘there won't be much leaving’. The present level of confusion around adaptation highlights the imperative of commencing discussions now to allow sufficient time to develop strategies which are both environmentally and socially responsible. This is important as ultimately it will be the community that will determine whether adaptation strategies are adopted or met with resistance.  相似文献   

长江口东南泥质区百年来稀土元素的组成及控制因素     

冯旭文  石学法  黄永祥  许冬  章伟艳  张富元 《地球化学》2011,(5):464-472

在210pb定年的基础上,分析了长江口外东南泥质区柱样沉积物稀土元素含量、特征参数分布特征及其与粒径、常量元素等的相关性,探讨了150 a以来稀土元素的来源、制约因素及对沉积环境的响应.结果表明,柱样稀土元素总量(ΣREE)变化范围不大,分布范围为158.38～197.87 μg/g,平均值为183.49μg/g,总体...  相似文献   

Dynamic p-enrichment schemes for multicomponent reactive flows     

C. Michoski  C. MirabitoC. Dawson  D. WirasaetE.J. Kubatko  J.J. Westerink 《Advances in water resources》2011,34(12):1666-1680

We present a family of p-enrichment schemes. These schemes may be separated into two basic classes: the first, called fixed tolerance schemes, rely on setting global scalar tolerances on the local regularity of the solution, and the second, called dioristic schemes, rely on time-evolving bounds on the local variation in the solution. Each class of p-enrichment scheme is further divided into two basic types. The first type (the Type I schemes) enrich along lines of maximal variation, striving to enhance stable solutions in “areas of highest interest.” The second type (the Type II schemes) enrich along lines of maximal regularity in order to maximize the stability of the enrichment process. Each of these schemes are tested on three model systems. The first is an academic exact system where basic analysis is easily performed. Then we discuss a pair of application model problems arising in coastal hydrology. The first being a contaminant transport model, which addresses a declinature problem for a contaminant plume with respect to a bay inlet setting. And the second, a multicomponent chemically reactive flow model of estuary eutrophication arising in the Gulf of Mexico.  相似文献   

Evaluation of a three-band model for estimating chlorophyll-a concentration in tidal reaches of the Pearl River Estuary, China   总被引：1，自引：0，他引：1  

Shuisen Chen  Ligang Fang  Hongli Li  Weiqi Chen  Wenrui Huang   《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(3):356-364

Accurate assessment of phytoplankton chlorophyll-a (Chla) concentration in turbid waters by means of remote sensing was challenging due to the optical complexity of turbid waters. Recently, a conceptual model containing reflectance in three spectral bands in the red and near-infrared range of the spectrum was suggested for retrieving Chla concentrations in turbid productive waters. The objective of this paper was to evaluate the performance of this three-band model to estimate Chla concentration in the Pearl River Estuary (PRE), China. Reflectance spectra of surface water and water samples were collected concurrently. The samples contained variable Chla (4.80-92.60 mg/m³) and total suspended solids (0.4-55.2 mg/L dry wt). Colored dissolved organic matter (CDOM) absorption at 400 nm was 0.40-1.41 m⁻¹; turbidity ranged from 4 to 25 NTU (Nephelometric Turbidity Units). The three-band model was spectrally calibrated by iterative and least-square linear regression methods to select the optimal spectral bands for the most accurate Chla estimation. Strong linear relationships (R²=0.81, RMSE=1.4 mg/m³, N=32) were established between measured Chla and the levels obtained from the calibrated three-band model [R⁻¹(684)-R⁻¹(690)]×R(718), where R(λ) was the reflectance at wavelength λ. The calibrated three-band model was independently validated (R²=0.9521, RMSE=6.44 mg/m³, N=16) and applied to retrieve Chla concentrations from the calibrated EO-1 Hyperion reflectance data in the PRE on December 21, 2006. The EO-1 Hyperion-derived Chla concentrations were further validated using synchronous in situ data collected on the same day (R²=0.64, RMSE=2 mg/m³, N=9). The spatial tendency of Chla distribution mapping by Hyperion showed gradually increased concentrations of Chla farther from the river mouths (although decreasing from east to west), which were disturbed by the combination of river outlets and tidal current in Lingding Bay of the PRE. This observation conformed to previous observations and studies, and could reasonably be explained by geographical changes. Also, results indicated that the slope of the three-band regression line decreased as the Chla concentration increased, resulting in the first sensitive band of the three-band model to move towards short wavelengths. These findings validated the rationale behind the conceptual model and demonstrated the robustness of this algorithm for Chla retrieval from in situ data and the Hyperion satellite sensor in turbid estuarine waters of the PRE, China.  相似文献   

Spatio-temporal characteristics and causes of changes in erosion-accretion in the Yangtze (Changjiang) submerged delta from 1982 to 2010     

SONG Chengcheng  SUN Xiaojing  WANG Jun  LI Mengya  ZHENG Lu 《地理学报(英文版)》2015,25(8)

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