Benthic Foraminifera Fauna from the Central Yellow Sea Mud (CYSM): New Regional Records and Environmental Implications Since the Late Pleistocene

Benthic foraminifera are widely used as indicators of marine environmental conditions due to their sensitivity to ecological changes and their excellent preservation in sediments. In this study, benthic foraminiferal assemblages from a sediment core collected in the central Yellow Sea were investigated to document faunal composition and examine temporal changes since the Late Pleistocene. A total of 54 benthic foraminiferal species belonging to 33 genera, 25 families, seven orders, three classes, and one phylum were identified. Among them, 12 species are newly recorded in Korean waters, reflecting the current incompleteness of regional faunal inventories and the importance of detailed taxonomic studies. The assemblages exhibit distinct stratigraphic variations. The lower interval (>30 ka) is characterized by low-diversity assemblages dominated by taxa commonly associated with marginal marine environments. The middle interval (ca. 20–25 ka) shows the occurrence of taxa typically reported from boreal to subarctic environments, suggesting changes in environmental conditions during the Last Glacial Maximum. In contrast, the upper interval (Holocene) is marked by increased species diversity and the dominance of taxa characteristic of normal marine shelf environments. These assemblage changes are interpreted as reflecting long-term responses of benthic communities to sea-level fluctuations, sedimentary conditions, and regional oceanographic variability in the Yellow Sea. In particular, the development of fine-grained deposits in the Central Yellow Sea Mud (CYSM) and the establishment of stable marine shelf conditions during the Holocene likely played important roles in shaping benthic habitats. This study provides new baseline data on benthic foraminiferal diversity in the Yellow Sea and demonstrates the potential of these assemblages as useful, though indirect, indicators for reconstructing past environmental changes. The results highlight the importance of integrating detailed taxonomic analyses with stratigraphic records to improve our understanding of marine biodiversity and paleoenvironmental variability in marginal seas.