兵庫県相生市沖の播磨灘北部における現生貝形虫群集と環境要因との関連

　Thirty ostracode species were recognized in eight surface sediment samples collected from the northern part of Harimanada Bay off Aioi City, Hyogo Prefecture, Southwest Japan. Two ostracode biofacies (BS and LC) were identified on the basis of Q-mode cluster analysis. Biofacies BS is distributed in the shallower area including Sakoshi and Murotsu bays, and contains abundant Bicornucythere bisanensis. Biofacies LC is found in the offshore area at water depths of more than 15 m, and is characterized by the occurrences of Loxoconcha viva and Cytheromorpha acupunctata, and relatively high species diversity. TOC and TN contents were highest in the shallower areas at about 2?2.5% and 0.3%, respectively. Spatial distribution of the ostracodes depends partly on differences in bottom-water salinity, and the TOC and TN contents in the substrates.