Diatom distribution in Holocene sediments from the northern West Caroline Basin (western equatorial Pacific) and their environmental significance

• Published in: Frontiers in Marine Science
• Main Authors: Chen, Min, Huang, Guobiao, Xu, Jishang, Wang, Chengtao, Xu, Jizheng, Qi, Hongshuai, Zhang, Aimei
• Other Authors: National Key Research and Development Program of China, Ministry of Natural Resources of the People's Republic of China, National Natural Science Foundation of China
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Frontiers Media SA 2023
• Subjects: Ocean Engineering; Water Science and Technology; Aquatic Science; Global and Planetary Change; Oceanography; Antarctic; Pacific; Antarc*
• Online Access: http://dx.doi.org/10.3389/fmars.2023.1110621; https://www.frontiersin.org/articles/10.3389/fmars.2023.1110621/full

Diatoms are an important component of submarine biogenic sediments and often used for carrying out palaeoceanographical reconstructions. To understand the relationship between diatoms and environment in the western equatorial Pacific, diatoms from the Holocene sediments in the northern West Caroline Basin were selected for analysis. We made quantitative statistics on diatoms and divided diatom assemblages through cluster analysis. A total of 53 species or varieties of diatoms belonging to 22 genera were identified. The range of diatom abundance was 0-88,373 valves/g. The diatoms found were mainly oceanic warm-water species. Overall, Azpeitia nodulifera was the species with the highest contribution, followed by Hemidiscus cuneiformis and Thalassiosira pacifica with these three species together accounting for approximately 80% in this area. We identified four diatom groupings and divided the study area into three regions. Diatom assemblage I in the West Caroline Basin was mainly affected by the North Equatorial Counter Current (NECC), Antarctic Intermediate Water (AAIW) and upwelling, and the supply of nutrients was relatively high. Assemblage II in the West Caroline Ridge was less influenced by currents, and thus had lower abundance and species diversity than assemblage I. The complex diatom assemblages in the Yap Trench were probably controlled by Upper Circumpolar Deep Water (UCPW) and Lower Circumpolar Deep Water (LCPW).