南海南部大陆架14ka来微型双壳类营养结构与海流活动

双壳类食悬浮物类与食沉积物类的发育变化是反映水动力环境的一种指标。对南海南部NS93- 1 2 - 58柱样 1 4ka来微型双壳类营养结构分析表明 ,晚更新世末次冰期向冰后期全新世转化阶段 ,食沉积物类一度较为发育 ,表明南海南部表层环流很不活跃 ,从这一转化阶段到全新世早期 ,双壳类食悬浮物类与食沉积物类的比例有规律地变大 ,表明随着气候转暖 ,海水温度增高 ,海平面上升 ,海流作用显著增强。该柱样整样分析表明 ,双壳类食悬浮物类占据着明显的优势 ,显示了 1 4ka来南海海流作用一直比较强烈。在全新世中晚期 ,双壳类主要栖息在次表层水团的海底 ,仍以食悬浮物类为主 ,可能与南海南部陆坡上升流发育有关

TROPHIC STRUCTURE OF MICROBIVALVE IN CORE NS93-12-58 AND OCEAN CURRENT CHANGE SINCE 14 ka B.P.IN SOUTHERN SHELF OF SOUTH CHINA SEA

Ratio of bivalvia suspension feeder to deposit feeder can be generally used as an indicator of hydrodynamic energy.The research on the trophic structure of microbivalvia since 14ka B.P. in core NS93 12 58 shows that at the stage of last glacial postglacial transition the deposit feeder was well developed for a time,which might indicate that the surface circumfluence wasn't very strong in the southern South China Sea.During the early Holocene since then,the ratio of bivalvia suspension feeder to deposit feeder appeared to increase regularly,which seemed to imply that with the climate warming,the sea level rose and the ocean current strengthened.As shown by the whole core,the bivalvia suspension feeder dominated all along,showing that the ocean current has been relatively strong since 14ka B.P. in the South China Sea.In the middle and late Holocene,though living on the seabed of sub surface water mass,the bivalve was still dominated by the suspension feeder.This might be closely related to the upwelling on the southern slope of the South China Sea.