湛江湾-雷州湾海域表层沉积物中底栖有孔虫分布特征及其环境意义

    Distribution characteristics of benthic foraminifera in surface sediments of Zhanjiang Bay-Leizhou Bay and its environmental significance

    • 摘要: 于2020年6月对湛江湾-雷州湾海域89个站位表层沉积物进行底栖有孔虫采样分析,共识别出52属103种,其中,玻璃质壳37属64种,胶结壳10属13种,瓷质壳5属26种。底栖有孔虫分布表现为湾内低、湾外高,由湾内向湾外增加的特点。对底栖有孔虫进行Q型因子分析,划分4个有孔虫组合,组合Ⅰ为Florilus scaphus - Pseudorotalia gaimardi,以暖水种为主,指示受南海暖流影响明显的内陆架浅水环境;组合Ⅱ为Nonion belridgense - Hemirotalia foraminulosa - Elphidium macellum,以咸水种为主,可能反映盐度值明显升高的浅水环境,具有海陆过渡带性质;组合Ⅲ为Hanzawaia convexa - Rosalina bradyi,以浅水种为主,指示受沿岸流与南海暖流共同影响的内陆架浅水环境;组合Ⅳ为Neoconorbina terquemi - Ammonia beccarii,以广盐种为主,反映了受沿岸流影响明显的滨海环境。综合分析影响底栖有孔虫组合分布的各种因素,认为温度、水深为控制研究海域底栖有孔虫分布的主要因素,同时,海流和底质类型也会对底栖有孔虫分布产生一定影响。

       

      Abstract: Benthic foraminifera from the surface sediments were sampled at 89 points in June 2020 in the Zhanjiang Bay-Leizhou Bay, Guangxi, SW China, and analyzed. A total of 103 species from 52 genus were identified, including 64 species from 37 genus with hyaline tests, 13 species from 10 genus with agglutinated tests, and 26 species from 5 genus with porcelaneous tests. The abundance of benthic foraminifera was characterized by an increase from inner bay to outer bay. Four assemblages were recognized based on Q-type factor analysis. AssemblagesⅠ, Florilus scaphus - Pseudorotalia gaimardi, was dominated by warm water species, indicating the shallow water environment of the inland shelf, which was obviously influenced by the South China Sea warm current. Assemblages Ⅱ, Nonion belridgense - Hemirotalia foraminulosa - Elphidium macellum, was mainly a saltwater species, which reflected a shallow water environment with significantly increased salinity in ocean-land transition zone. Assemblages Ⅲ, Hanzawaia convexa - Rosalina bradyi, was dominated by shallow-water species, indicating the shallow water environment of inland shelf affected by coastal current and South China Sea warm current. Assemblages Ⅳ, Neoconorbina terquemi - Ammonia beccarii, consisted mainly of eurysaline species, reflecting the coastal environment that obviously affected by the coastal current. A comprehensive analysis on various factors on the distribution of benthic foraminiferal assemblages showed that bottom water temperature and water depth are main impact factors on the distribution of benthic foraminifera assemblages in the study area. In addition, the distribution of benthic foraminifera is also influenced by ocean current and substrate type.

       

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