Ecological and taphonomical influences on coccoliths in surface sediments in the shelf of the Yellow and East China Seas. (15th May 2017)

• Record Type: Journal Article
• Authors: Jin, Xiaobo; Liu, Chuanlian
• Is Part Of: Continental shelf research. Volume 140(2017)
• Page Start: 27
• Page End: 36
• Publication Date: 2017-05-15
• Subjects: Coccolith -- Surface sediment -- Yellow Sea -- East China Sea -- Ecology -- Taphonomy; Continental shelf -- Periodicals; Submarine geology -- Periodicals; 551.41
• DOI: 10.1016/j.csr.2017.04.008
• Languages: English
• ISSNs: 0278-4343

Abstract

Abstract: Coccoliths, combined with sediment grain size, carbonate calcium and organic matters content, were analyzed to assess the ecological and taphonomical influences on coccolith distribution patterns in surface sediments in the continental shelf of the Yellow and East China Seas. Coccolith abundances ranged from 0 to 2.08×10 9 coccoliths g −1 sediment. The increasing abundance from the coastal inner shelf to the seaward middle shelf generally reflects the ecological fact that living coccolithophores are more abundant in the mesotrophic shelf waters than in the eutrophic coastal waters, although their deposits are still controlled by taphonomical effects, such as bottom (tidal) currents and calcite preservation conditions. Most abundant coccoliths are found in the fine-grained sediments of southwestern Cheju Island, where both ecology and taphonomy favor coccolith preservation. Still, large densities of coccoliths (>10 8 coccoliths g −1 sediment) are also found in coarse-grained relict sediments in the middle shelf. Coccolith assemblages were predominated by Gephyrocapsa oceanica and Emiliania huxleyi . The relative abundance of E. huxleyi, in addition to ecological reasons, may relate to selective post-mortem dissolution, since small E. huxleyi coccoliths are more susceptible to dissolution. Coccolith calcite has minor contributions (<1% to 12%) to total sediment CaCO3, and the main parts are attributed to terrigenous CaCO3 debris and relict shell fragments. Highlights: Coccolith distribution in surface sediments of the Yellow and East China Seas. Coccolith absolute abundances combined with grain size and CaCO3 % of sediments were carried out. Ecological and taphonomical influences on coccolith distribution. The relative abundance of Emiliania huxleyi is related to coccolith preservation. Coccoliths contribute minor to carbonate calcium content in sediments in the study area.