冬季和夏季南海北部浮游纤毛虫的分布特点

摘要

We investigated the abundance and biomass of planktonic ciliates in the northern South China Sea in winter and summer,2009.The average abundance of ciliates in the winter and summer were (486±484) and (809±1008) ind/L,respectively.The average biomass of ciliates in winter and summer were (2.84±3.26) and (1.96±3.80) μg C/L,respectively.The depth-weighted average ciliate abundance and biomass decreased from coastal areas to off-shore areas in both seasons,and were higher along Transects S 1 than Transect S2.Ciliates tended to accumulate in the sub-surface layers in winter.Ciliate abundance and biomass were usually higher in the surface or middle layers in summer,although sometimes ciliates were located near the bottom layers in the off-shore stations.Tintinnids were rarely detected in winter,while 22 tintinnid species of 14 genera were identified in summer.Tintinnids occupied 1.7％ and 22.6％ of the total ciliate abundance in winter and summer,respectively.%本文报道2009年冬季和夏季南海北部浮游纤毛虫丰度和生物量的水平分布和垂直分布特点.冬季和夏季纤毛虫的平均丰度分别为(486±484)ind/L和(809±1008)ind/L;平均生物量分别为(2.84±3.26)μg C/L和(1.96-3.80)μg C/L.冬季和夏季纤毛虫丰度和生物量的水平分布特点一致,呈现由近岸向远岸降低的趋势,珠江口外断面的水体平均纤毛虫丰度和生物量均明显高于海南岛东部断面,该趋势在夏季表现得更为突出.冬季和夏季纤毛虫丰度和生物量的垂直分布特点不同,冬季纤毛虫丰度和生物量在水体的次表层较高;夏季纤毛虫丰度和生物量总体上在表层或中层出现高值.夏季在珠江口外断面远岸150m水深处有一个纤毛虫丰度和生物量的高值区,这个现象在以往的研究中没有发现过.冬季砂壳纤毛虫很少检出,夏季共鉴定出砂壳纤毛虫14属22种,冬季和夏季砂壳纤毛虫丰度占纤毛虫丰度的比例分别为1.7％和22.6％.