珠江口和琼东南盆地天然气水合物形成和稳定分布的地球化学边界条件及其分布区   总被引：22，自引：0，他引：22  

陈多福  姚伯初  赵振华  徐文新 《海洋地质与第四纪地质》2001,21(4):73-78

通过对南海北部陆缘珠江口和琼东南盆地气田的天然气形成水合物的地球化学计算模拟及地质地球化学条件分析，对珠江口和琼东南盆地天然气形成水合物的地球化学边界条件及分布区进行了研究。认识到南海北部陆缘琼东南和珠江口盆地内的断裂构造是天然气向海底渗漏的通道，为天然气水合物在海底的形成提供了物源；盆地内巨厚的第四纪富有机质沉积也为天然气水合物形成提供了充足的细菌成因生物气源。在海底温度2－16℃范围内，琼东南盆地气田10种天然气和珠江口盆地气田18种天然气形成水合物的压力有比较大的范围，随温度增高，天然气水合物形成的压力增高；盆地间和各天然气样品之间形成水合物的压力均是不一致的。在南海海水平均盐度3．4％条件下，结合海底温度与水深变化资料，珠江口和琼东南盆地天然气水合物形成和稳定分布的海区是不同的，珠江口盆地小于230m水深的海区没有天然气水合物的形成，在230－760m水深的海区可能有天然气水合物的存在，天然气水合物的稳定分布区应该在大于860m水深的深水区；在琼东南盆地水深小于320m的海区不可能有天然气水合物的形成，在320－650m水深的海区可能有天然气水合物的存在，大于650m水深的海区是天然气水合物的稳定分布区。  相似文献   

黄河口附近海域化学需氧量和石油烃分布及其关键控制环境因子分析   总被引：1，自引：0，他引：1  

曲良 《海洋通报》2020,39(3):335-341

于2009年12月、2010年5月、2011年9月、2013年5月和2014年10月,在黄河口附近海域进行了5个航次调查,研究了该海域的化学需氧量(COD)和石油烃的分布情况以及季节变化。结果表明,COD整体呈冬季低、春季高的趋势,而石油烃无明显季节变化趋势。平面分布上,春季和秋季COD高值主要分布在靠近黄河口海域。春季和冬季石油烃高值主要位于调查海域的东北部区域。相关分析结果表明盐度、温度、pH、悬浮物、溶解氧及磷酸盐是影响COD的主要环境因素,而石油烃主要受盐度、温度、pH、无机氮、磷酸盐的影响。进一步多元回归分析结果表明,p H、盐度和溶解氧是影响COD的关键因子,温度是影响石油烃的关键因子。  相似文献   

珠江口浮游幼虫的生态研究     

李开枝  尹健强  黄良民  邱大俊 《海洋通报》2007,26(6):42-47

根据2002—2003年珠江口12个航次的调查资料,分析探讨了不同调查时间和区域浮游幼虫的组成类型、丰度变化和环境因子的影响。以表层盐度(S)变化将调查海域划分成三个区域:I区(S<25)、II区(2530)。12个航次的调查结果显示:调查海域共出现浮游幼虫12个类型,隶属5个动物门,II区和III区的类型数一般高于I区,软体动物门和棘皮动物门的幼虫只出现在II区和III区。其中2002年7月(夏季)、2003年1月(冬季)和4月(春季)的3个大航次结果表明珠江口浮游幼虫的平均丰度为61ind/m3,三个区域的平均丰度比较为II区(124ind/m3)>I区(33ind/m3)>III区(27ind/m3),春夏季的丰度高于冬季。另外在I区进行了9个小航次调查的研究表明:I区浮游幼虫平均丰度较高,月份之间的丰度差别明显,不同站位之间也有差别。温度和食料是影响珠江口浮游幼虫丰度变化的主要因素。  相似文献   

九龙江河口区表层水铀同位素的粒级分布          下载免费PDF全文

吕娥  张磊  陈敏  邱雨生  邢娜  杨伟锋  李艳平  黄奕普 《海洋学报》2007,29(4):59-68

利用微滤和超滤技术研究了九龙江河口区表层水中铀及其同位素组成的粒级分布和地球化学行为.结果表明,溶解态(<0.4μm)中低分子量组分(<10 000 u)占主要份额,胶体态(10 000 u~0.4μm)238U所占比例不足1%,且随盐度的增加其所占份额逐渐降低.溶解态、低分子量组分和胶体态238U的比活度与盐度之间存在良好的线性正相关关系,证实它们在九龙江河口区呈现保守行为.在颗粒态(>0.4μm)中,各粒级组分238U所占份额主要受控于相应颗粒物的浓度,在盐度小于20的区域,各粒级颗粒组分238U占颗粒态的份额有如下变化次序:10~53μm>2~10μm>0.4~2μm>大于53μm,而在盐度大于30的近外海站位,该次序发生一些变化:0.4~2μm>10~53μm>2~10μm>大于53μm,最小粒级颗粒组分238U的贡献有所增加,反映了自生铀贡献的加强.九龙江河口区表层水中溶解态(包括低分子量组分和胶体态)的234U/238U)_A.R.均大于1,显示出234U过剩的特征,而各粒级颗粒组分中的234U/238U)_A.R.则接近于平衡值(1.0).这一现象与陆地岩石风化过程中水体对铀的淋滤释出量及234U的优先浸出有关.对232Th/238U质量比的研究显示,溶解态及其所包括的低分子量组分和胶体态的232Th/238U质量比均小于1,而颗粒态及其所包括的4个粒级组分中的232Th/238U质量比均大于1,反映了向外海输送过程中铀、钍地球化学行为的差异.  相似文献   

Depth- and current-induced effects on wave propagation into the Altamaha River Estuary, Georgia     

KiRyong Kang  Daniela Di Iorio   《Estuarine, Coastal and Shelf Science》2006,66(3-4):395-408

A study of sea surface wave propagation and its energy deformation was carried out using field observations and numerical experiments over a region spanning the midshelf of the South Atlantic Bight (SAB) to the Altamaha River Estuary, GA. Wave heights on the shelf region correlate with the wind observations and directional observations show that most of the wave energy is incident from the easterly direction. Comparing midshelf and inner shelf wave heights during a time when there was no wind and hence no wave development led to an estimation of wave energy dissipation due to bottom friction with corresponding wave dissipation factor of 0.07 for the gently sloping continental shelf of the SAB. After interacting with the shoaling region of the Altamaha River, the wave energy within the estuary becomes periodic in time showing wave energy during flood to high water phase of the tide and very little wave energy during ebb to low water. This periodic modulation inside the estuary is a direct result of enhanced depth and current-induced wave breaking that occurs at the ebb shoaling region surrounding the Altamaha River mouth at longitude 81.23°W. Modelling results with STWAVE showed that depth-induced wave breaking is more important during the low water phase of the tide than current-induced wave breaking during the ebb phase of the tide. During the flood to high water phase of the tide, wave energy propagates into the estuary. Measurements of the significant wave height within the estuary showed a maximum wave height difference of 0.4 m between the slack high water (SHW) and slack low water (SLW). In this shallow environment these wave–current interactions lead to an apparent bottom roughness that is increased from typical hydraulic roughness values, leading to an enhanced bottom friction coefficient.  相似文献   

Spatial and temporal variations of mesozooplankton in the Pearl River estuary, China   总被引：10，自引：0，他引：10  

K.Z. Li  J.Q. Yin  L.M. Huang  Y.H. Tan   《Estuarine, Coastal and Shelf Science》2006,67(4):543-552

This paper examines spatial and temporal variations of mesozooplankton abundance, biomass and community structure during three cruises of July 2002 (summer), January 2003 (winter), and April 2003 (spring) in the Pearl River estuary, China. Zooplankton abundance and biomass fluctuated widely and showed distinct heterogeneity in the Pearl River estuary. A total of 154 species were identified during three surveys. The number of zooplankton species richness was strongly linked to salinity. Hierarchical cluster analysis identified three zooplankton groups during this study. Estuarine, neritic and pelagic groups corresponded to the upper, middle and lower reaches in the Pearl River estuary. The difference among groups could be mainly ascribed to changes in the relative contributions of the dominant species. The fluctuations in the zooplankton abundance, biomass and community structure were determined by the interactive effects of freshwater inflow, tidal and coastal currents, chlorophyll a, salinity and temperature. Significant spatial variability in the distribution of zooplankton species, abundance and biomass can be ascribed to the virtual presence of a horizontal gradient in salinity.  相似文献   

Responses of a Mediterranean soft bottom community to short-term (1993-1996) hydrological changes in the Rhone river   总被引：1，自引：0，他引：1  

Salen-Picard C  Arlhac D  Alliot E 《Marine environmental research》2003,55(5):409-427

The polychaete fauna of muddy bottoms off the Rhone delta (NW Mediterranean) was seasonally sampled at two sites at 70 m depth, from 1993 to 1996. During this period, five severe flood events occurred. A clustering analysis (distance coefficient of Whittaker) and three way fixed factor ANOVAs (site x season x year) showed strong year-to-year changes in species density and community structure, changes that masked seasonal variations. Total density increased by a factor of 3 and density of most species significantly increased following the first flooding event. Changes in the community structure were due to the successive dominance of a few species. The opportunistic species, such as Cossura sp., Mediomastus sp. and Polycirrus sp., exhibited peaks in density 1-3 months after the flood. These peaks were followed by a drastic decline. For species with a long life span, such as Sternaspis scutata, a slower but continuous increase in density was observed which was maintained for several months. The density fluctuations of these species exhibited a good correlation with river flow with time lags of 1-2 years. The successional dynamics observed are explained according to the geographical origin of the floods and the biology and feeding ecology of species.  相似文献   

珠江三角洲及珠江口海区的空气微生物含量     

陈皓文 《热带海洋学报》1996,(3)

１９９４年６，７月，调查了广州、深圳、珠海及珠江口海区的空气微生物粒子沉降量状况。发现空气微生物粒子总量、真菌粒子量、真菌粒子数／总菌粒子数百分比在三市中不一致。这三种数据一般是陆上的高于海上。随着距陆的增加，都市影响的减弱和海面的开阔，空气微生物含量呈减少之势，显示出海洋新鲜空气对陆上污染空气的调节、净化作用。文中还分析了空气微生物有关参数与气温、风力或相对湿度间的相关关系。  相似文献   

珠江三角洲地质灾害的模糊综合评价     

詹文欢  钟建强 《热带海洋学报》1995,(1)

珠江三角洲地质灾害种类的多样性与其所处的复杂地质环境和多变的气候条件密切相关。文章选用了地震活动、活动断裂、地壳升降运动、软土地基、地面塌陷以及冲、淤积等６个主要因素作为评价指标，并用模糊数学方法对珠江三角洲内１７个小区作了计算，结果表明该区大部分地区属于轻灾害区，只有滨海沿岸地区属于较重灾害区。  相似文献   

山溪性可冲性强潮河口曹娥江高水位初步研究     

潘存鸿  蔡军 《海洋学研究》2001,19(1):11-18

应用多年的实测资料 ,分析了曹娥江河口高水位成因 ,结果表明 ,曹娥江河口洪水位具有山溪性和可冲性的特点 ,人类活动对高水位有较大影响。应用统计分析法和成因分析法推求 1 %设计高水位 ,讨论了成因分析法中上、下边界条件的选取 ,其选取原则对其他潮汐河口确定设计高水位具有借鉴意义  相似文献