上海国土资源2025，Vol.46Issue(1)：57-66,10.DOI:10.3969/j.issn.2095-1329.2025.01.009
北部湾北部近百年沉积环境变化及硅藻记录响应
Sedimentary environmental changes and diatom assemblage responses in the northern Beibu Gulf over the past century
摘要
Abstract
The Beibu Gulf,situated on the southern margin of the Asian continent as a continental shelf sea,harbors valuable records of sedimentary environmental changes.Currently,it faces environmental challenges such as ecological degradation and a shrinking gulf area,posing serious threats to its sustainable development.Reconstructing the sedimentary and marine ecological environments of the Beibu Gulf over the past century and identifying the influencing mechanisms of natural factors and human activities on the marine environment can provide a basis for predicting future trends in sedimentary evolution and its impact on phytoplankton communities.The results indicate that the sedimentary environmental evolution in the northern Beibu Gulf can be divided into four stages:(1)From 1881 to 1913,fine-grained sediments prevailed due to limited river runoff and weak hydrodynamics,favoring diatom growth and preservation.Diatom abundance was high,dominated by brackish water species Cyclotella striata and shallow marine species Paralia sulcata,with relatively low freshwater species content.(2)From 1913 to 1962,sediment grain size fluctuated significantly,reflecting unstable terrestrial inputs and hydrodynamic conditions,leading to a marked decrease in diatom abundance.Human activities,such as dam construction and aquaculture,began to influence the sedimentary environment around 1930,primarily through altering sediment grain size,indirectly affecting diatom preservation.Peaks in regional rainfall corresponded to peaks in terrestrial organic matter input and increases in freshwater diatom abundance,indicating that natural factors remained dominant in structuring diatom communities.(3)From 1962 to 1992,reduced regional rainfall weakened river runoff and decreased terrestrial input,resulting in relatively stable sediment grain size.(4)From 1992 to 2005,increased regional rainfall led to higher terrestrial input and coarser sediment grain size,causing extremely low diatom abundance but an increase in freshwater species.The analysis of core QZG in the northern Beibu Gulf has uncovered the mechanisms by which the evolution of the sedimentary environment over the past century has influenced local ecological systems.The transformation of coastal environments not only affects the stability of marine ecosystems and the preservation of biodiversity but is also intricately tied to the sustainable development of human society.A thorough investigation of this evolutionary process holds significant scientific and practical value for safeguarding the ecological security of the Beibu Gulf and global coastal zones,as well as for facilitating the rational and efficient use of their resources.关键词
硅藻/粒径/碳氮同位素/沉积环境/北部湾Key words
diatoms/grain size/carbon and nitrogen isotopes/sedimentary environment/Beibu Gulf分类
海洋科学引用本文复制引用
刘陈曦,王欣怡,李显富,李冬玲..北部湾北部近百年沉积环境变化及硅藻记录响应[J].上海国土资源,2025,46(1):57-66,10.基金项目
国家自然科学基金(42376236) （42376236）
