渤海湾近岸海底表层硅藻的组合特征及其沉积环境

发布时间：2017-12-28 16:33

本文关键词：渤海湾近岸海底表层硅藻的组合特征及其沉积环境　出处：《天津师范大学》2017年硕士论文　论文类型：学位论文

【摘要】：以渤海西侧的天津湾与渤海东侧的复州湾浅海区为研究对象,分别对天津湾40个表层沉积物样品与复州湾8个表层沉积物样品的进行了硅藻分析。查明了表层沉积硅藻组成、优势种及组合的分布特征。并结合样品所处地貌与粒度特征,明确了研究区域的沉积环境,探讨了河流与环流对硅藻组合与沉积环境的影响。对复州湾8个不同地点表层沉积物样品的硅藻种属百分含量做聚类分析,将硅藻划分为 4 组:Ⅰ 组主要硅藻组合为 Paralla sulcate-Biddulphia aurita-Rhaphoneis surirella;Ⅱ组主要硅藻组合为Paralla sulcate-Coscinodiscus excentrcus-Cyclotella stylorum;Ⅲ组主要硅藻组合为Coscinodiscus radiates-Cyclotella stylorum;Ⅳ 组主要硅藻组合为Paralla sulcate-Coscinodiscus radiates-Coscinodiscus excenrcus。结合粒度分析与地貌特征得出:Ⅰ组大体为受河流影响较小内湾环境;Ⅲ组为受河流影响较小的近岸基岩环境;Ⅱ组与Ⅳ组为受河流影响相对较强的内湾环境。对天津湾40个不同地点表层沉积物样品的硅藻种属百分含量做聚类分析,将硅藻划分为 4 组:Ⅰ 组主要硅藻组合为Coscinodiscus radiates-Coscinodiscus excentrcus-Cyclotella stylorum;Ⅱ 组主要硅藻组合为 Coscinodiscus radiates-Cyclotella stylorum-Coscinodiscus excentrcus;Ⅲ组.硅藻组合为 Coscinodiscus excentrcus-Coscinodiscus radiates-Coscinodiscus lineatus;Ⅳ组硅藻组合为 Paralla sulcate-Coscinodiscus excentrcus-Coscinodiscus lineatus。结合粒度与地形资料探讨得出:I组为受河流作用较少的内湾环境;Ⅱ组为受河流作用的内湾环境;Ⅲ组为受河流作用较大的内湾环境;IV组为受河流作用较大的河口内湾环境。天津湾与复州湾外洋种硅藻 Dictycha fibula、Thalassiosira nizschioides、Coscinodiscus属与Actinocyclus属的百分含量差异较大。复州湾所有外洋种平均百分含量的总和仅为37.65%,而天津湾却高达74.01%,表明天津湾与外洋水体有更好的连通性,与两地海底地形差异相符。在复州湾含淡水种硅藻的样点中,发现的淡水硅藻种类与数量都较少,仅发现Epithemia turgida,Melosira granulata,Tabellaria fenestrata。而天津湾含淡水种硅藻的样点中,发现的淡水硅藻种类与数量都较前者多,其中发现的淡水种硅藻有:Epithemia hyndmanii,Gyrosigma acuminatum,Melosira granulata,Navicula cryptotenella,Navicula mediocostata,Surirella fastuosa,Syedra ulna,Tabellaria fenestrata。复州湾能发现由复州河河水入海时经过湖沼时带入海区的湖沼环境普通种Epithemia turgida,而在天津湾段却没鉴定出。虽然同为内湾环境,但两岸淡水种硅藻差异巨大。表明两区域海区淡水种硅藻来源有区别,受附近入海河流影响明显。
[Abstract]:Based on the Tianjin Bay on the west side of Bohai and the Fuzhou Bay shallow sea area on the east side of Bohai, 40 diatomite samples from Tianjin Bay and 8 surface sediments from Fuzhou bay were analyzed. The distribution characteristics of the composition, dominant species and assemblage of the surface deposited diatom were found out. Combined with the features of the geomorphology and granularity of the samples, the sedimentary environment of the study area was clarified, and the effects of rivers and circulation on the diatom assemblage and sedimentary environment were discussed. Analysis of the species percentage of cluster Fuzhouwan at 8 different locations in surface sediment samples, diatoms are divided into 4 groups: group I Paralla sulcate-Biddulphia aurita-Rhaphoneis for the main diatom assemblages of Surirella; group II Paralla sulcate-Coscinodiscus excentrcus-Cyclotella as the main diatom assemblage stylorum; group III Coscinodiscus radiates-Cyclotella stylorum as the main diatom assemblage; IV group Paralla sulcate-Coscinodiscus radiates-Coscinodiscus excenrcus for diatom assemblages. Combined with particle size analysis and geomorphologic characteristics, I concluded that group I is generally less affected by rivers than inner bay environment. Group III is a nearshore bedrock environment which is less affected by rivers. Group II and group IV are relatively inshore environments with relatively strong River influence. Analysis of the species percentage do clustering on the Gulf of Tianjin at 40 different locations in surface sediment samples, diatoms are divided into 4 groups: group I Coscinodiscus radiates-Coscinodiscus excentrcus-Cyclotella for the main diatom assemblages of stylorum; group II Coscinodiscus radiates-Cyclotella stylorum-Coscinodiscus as the main diatom assemblage excentrcus; III group. Coscinodiscus excentrcus-Coscinodiscus radiates-Coscinodiscus lineatus diatom assemblages of diatoms in group IV; Paralla sulcate-Coscinodiscus excentrcus-Coscinodiscus lineatus combination. Combined with grain size and topographic data, it is concluded that group I is an inner bay environment with less action by rivers, group II is an inner bay environment with river action, and group III is an inner bay environment with larger rivers. IV group is an estuarine environment with large river action. The Gulf of Tianjin and Fuzhouwan overseas Dictycha fibula, Thalassiosira nizschioides, diatoms and Coscinodiscus are differences in content and Actinocyclus is larger. The sum of Fuzhouwan all overseas average percentage is only 37.65%, while the Tianjin Bay was as high as 74.01%, shows that the connectivity is better in Tianjin bay with the overseas water, consistent with the two different terrain. The species and quantity of freshwater diatoms found in Fuzhou Bay freshwater diatom samples are less. Only Epithemia turgida, Melosira granulata, Tabellaria fenestrata are found. The samples of Tianjin bay with freshwater diatoms in freshwater diatoms found in species and quantity than the former, which found that the freshwater diatoms are: Epithemia hyndmanii, Gyrosigma acuminatum, Melosira granulata, Navicula cryptotenella, Navicula mediocostata, Surirella fastuosa, Syedra ulna, Tabellaria fenestrata. Fuzhouwan can be found by Fuzhouhe River into the sea through the lake with the sea area of lake environment common species in the Gulf of Tianjin and Epithemia turgida, was not identified. Although it is the same as the inner bay environment, there are great differences in freshwater diatom on both sides of the Taiwan Straits. It shows that there are different sources of freshwater diatom in the two regional sea area, which are obviously affected by the rivers near the sea.
【学位授予单位】：天津师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：Q949.27

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