한국 남해 대륙붕 저서성 유공충 군집 분포와 종 다양성

Species Diversity and Distribution of Benthic Foraminiferal Assemblages in South Continental Shelf, Korea

To understand the distribution and formation mechanism of benthic foraminiferal assemblages, grain size analysis, 14C radiocarbon dating, and benthic foraminifera analysis conducted on eighteen surface sediments collected from the South con- tinental shelf, respectively. Surface sediment composed of sandy mud~muddy sand facies with an average of 42.54% of sand, 18.20% of silt, and 38.20% of clay. Sandy and muddy facies are relict-palimpsest and modern sediment, respectively. Benthic foraminifera are classified into a total of 71 genera and 150 species. The species diversity of benthic foraminifera is 3.0~3.8 (average, 3.6). Dominant species (production rate 10% over) composed 5 species: Bolivina robusta, Cibicides lobatulus, Eilohedra nipponica, Pseudoparrella tamana. In the result of 14C radiocarbon datings and comparison of habitat environment, Bolivina robusta (2,360±40 B.P.), Cibicides lobatulus (2,518±33 B.P.), Eilohedra nipponica were the late Holocene fossil species. Pseudoparrella tamana was modern species. In the result of cluster analysis, four assemblages composed of C. lobatulus, C. lobatulus - B. robusta, E. nipponica- B. robusta assemblages distributed in the palimpsest sediment of 80~100 m in water depth and P. tamana assemblage distributed in the modern muddy sediment were classified broadly. Therefore, species diversity and distribution of benthic foraminiferal assemblages in the South continental shelf may be affected by the water depth change due to the sea level rise in the late Holocene, and the sediment facies change due to the sedimentation of muddy sediment inflow from Yangtze river and coastal area of South sea.