Whether human-induced activities could change the gradient pattern of coastal land use along the sea-land direction: a case study in Manila Bay,Philippines

Increasing intense human activities have largely changed the coastal landscape and caused many environmental issues. However, whether human-induced activities could change the coastal land use gradient pattern, an important coastal zonal characteristic along the sea–land direction, remains unclear. Manila Bay was selected as the study area in this work. According to the distance of the land use and land cover(LULC) to the coastline, we clustered the typical coastal land use sequence patterns(CLU...     

南麂列岛海洋自然保护区潮间带贝类资源时空分布

为了解南麂列岛海洋自然保护区潮间带贝类十多年来的动态变化,在1992年研究基础上,于2003年度再赴南麂列岛对岩、沙相贝类进行了研究.本次调查鉴定出贝类105种,其中岩相93种、沙相12种,6种为南麂列岛新记录种,对岩相、沙相贝类组合的生态特征进行了分析,岩相多样性和均匀度指数(1.25~2.20和0.54~0.70)高于沙相的(0.23~0.95和0.17~0.94).岩相贝类数量为3025.70g/m2和2660个/m2,生物量垂直分布为低潮区最高(6471.99g/m2),中潮区居中(3772.09g/m2),高潮区最小(78.35g/m2),栖息密度为中潮区最大(4245个/m2),低潮区居中(2973个/m2),高潮区最小(439个/m2).沙相贝类数量为16.81g/m2和11个/m2,低潮区(29.43g/m2和11个/m2)大于中潮区(14.01g/m2和10个/m2).通过与以往资料比对发现,岩礁贝类数量有所增加,沙滩贝类数量则明显下降,监控区贝类数量明显多于其他区域,对贝类资源变化产生影响的相关因子作了分析探讨.     

长江口外缺氧区沉积物中元素分布的氧化还原环境效应

对取自长江口外缺氧区及其邻近海域表层沉积物样品进行了粒度组成和元素(主要包括氧化还原敏感性元素和亲碎屑元素)丰度的分析与测试,对长江口外缺氧区缺氧环境对元素分布的影响进行了探讨,提出了长江口外缺氧区沉积物中氧化还原敏感性元素(Redox sensitive elements,简称RSE)分布的氧化还原环境效应。亲碎屑元素丰度的分布显示出明显的粒控效应,而氧化还原敏感元素的分布受粒度效应的制约很弱,主要受离岸缺氧区还原环境的制约,具有在缺氧区富集的特点。缺氧环境对RSE分布的影响超过了元素的粒控效应,从而使研究区RSE的分布呈现出典型的氧化还原环境效应。     

海岸分类的回顾与展望

海岸带是陆地与海洋相交的区域,受到多种自然和人为因素的影响,进行合理的海岸分类对于科学认识、合理开发、有效管理和保护海岸带资源至关重要。本文回顾海岸带分类的研究历程,探讨不同分类方案的划分依据,并强调海岸带的多维性和复杂性。从早期的地理地貌特征划分到现代的综合性海岸分类体系,海岸带分类方案不断演变,并受到各个时代的资料积累、知识体系、观测技术及制图展示效果等方面的深刻影响。不同国家和地区的学者在分类方案上存在一定的差异,体现了各地的地理地质背景、研究重点、开发利用方式等方面的特点,也隐含着研究人员的观察视角。主要源于陆地的物质属性和主要源于海洋的能量条件,越来越成为海岸分类的重要指标。人类活动对海岸带的影响不容忽视,人工海岸的比例已经迅速上升,但在海岸带分类体系中的研究仍有所欠缺,原因包括世界观、方法论和价值观等多个层面。建议从海岸动力作用环境和沉积物供应条件两方面考虑人类活动如何影响海岸带系统状态,而海岸带类别体系里可以增加人工建造和人工改造两个新的大类。通过深化分类方法和细化分类层次,同时向综合与细化两个方向推动海岸分类体系研究,可以更好地实现海岸带资源的保护与可持续利用,促进人与...     

东海丽西洼陷缓坡带中—下古新统成岩演化

丽西洼陷的储层品质是长期以来制约勘探的关键要素之一。为了分析丽西洼陷缓坡带新的勘探层系−中—下古新统的有效储层发育问题,综合利用岩石薄片鉴定、扫描电镜（SEM）分析、X衍射分析、镜质体反射率测定、流体包裹体分析等技术,研究了丽西洼陷缓坡带中—下古新统的储层成岩演化特征。研究表明,丽西洼陷缓坡带中—下古新统成岩演化具有南北差异性,总体上现今南部演化程度高于北部。在斜坡的主体部位（斜坡中带）,南部中—下古新统可进入中成岩B期,而北部中—下古新统总体处于中成岩A期。通过实验现象及结果分析,本研究认为影响原生粒间孔隙保存的2大关键要素为刚性颗粒含量和浅埋藏时碳酸盐沉淀;影响次生溶蚀孔形成的2大关键要素为地表酸性水、幔源二氧化碳和烃源岩演化排出的酸等形成的3类酸性环境,以及岩石早—中期碳酸盐含量和长石含量。     

福建漳浦前湖湾有孔虫群落及其沉积环境

对福建漳浦前湖湾潮间带两个钻孔岩心和表层沉积物中的有孔虫进行分析研究,有孔虫出现在钻孔最上部厚约2.46-2.96m的砂层中.根据群落优势种生态和非种特征判断,该段各样品有孔虫沉积环境均为近岸浅水环境,尽管其间海面有过3次上下波动变化.根据地层关系判断,其当为现代的产物.     

经济手段在海岸带环境管理中的应用

简要阐述了环境经济学的基本理论,并以青岛为例,分析了海岸带环境管理现状和现行经济手段存在的问题,提出了运用经济手段加强海岸带环境管理的建议。     

基于潜标观测的黑潮-亲潮混合区近惯性能量季节变化特征研究

近惯性内波广泛存在于全球海洋,是维持深层海洋跨等密度面湍流混合及海洋层结的重要能量来源。基于黑潮-亲潮混合区的多年深海潜标数据,分析了:(1)该海域近惯性内波及其能量的季节变化特征与影响因素,(2)上层和深层近惯性运动的频率、波数谱及垂向分布等特征。结果表明,该海域存在丰富的近惯性动能,无论海洋上层还是深层均呈现显著的冬季强、夏季弱的季节变化特征,冬季(12～2月)上层的近惯性能量可占全年能量的41%,深层近惯性信号同样显著,同潮汐信号相当。平板模型分析表明,该区域近惯性动能的季节循环特征主要受风场的季节变化所主导,同时受到黑潮延伸体流轴的摆动调制。     

东海陆架前缘斜坡北部的滑塌带

从1994年对东海陆架前缘斜坡北部实测的8条浅地层记录中,我们发现这些测线上都有滑塌构造,并形成了一条平行于陆架转折线的滑塌带,滑塌带呈NNE向展布,平均宽约7.5km,它们是沉积物流从陆坡上部向下移动的证据。     

Factors influencing the oxidation,reduction, methylation and demethylation of mercury species in coastal waters

The objective of this study was to examine the redox reactions and other transformations of mercury (Hg) species in surface waters, and the factors determining the rates of these reactions. For the redox studies completed at the Chesapeake Biological Laboratory (CBL), two isotopes (¹⁹⁹Hg^II and ²⁰²Hg⁰) were added into different types of filtered water (fresh to seawater) to examine the oxidation and reduction reactions. Further studies of both the redox reactions and methylation/demethylation reactions of Hg were conducted with unfiltered water on board research vessels during cruises in May and July 2005 on the Chesapeake Bay and shelf. While CH₃¹⁹⁹Hg^II was added to allow the examination of demethylation, ²⁰¹Hg^II was used to examine both reduction and methylation, and ²⁰²Hg⁰ was used to examine oxidation. Overall, the results showed that both Hg oxidation and reduction were simultaneously occurring and were photochemically mediated in the waters investigated. In contrast to the previously assumed “unreactive” nature of Hg⁰, the studies found that the magnitude of the rate constant for Hg⁰ oxidation was greater than that for reduction, indicating its importance in estuarine and coastal waters. In addition, both experiments at CBL and on board ship showed that Hg^II reduction was similar in magnitude, suggesting that biotic processes were relatively unimportant. While no measurable methylation occurred during the incubation period during the on board studies, concentration of CH₃¹⁹⁹Hg^II decreased over the time during the experiments. It appeared that the demethylation processes were not dominantly photochemically driven, but could be microbially mediated. Further studies are needed in order to help better understand Hg redox and transformations in natural water systems.