台湾岛以东海域束毛藻种群的组成与分布

摘要

分别对1996年5月和1997年7月台湾岛以东黑潮及邻近海域51个采样站位的87份网采浮游植物进行了分析,总结了束毛藻种群的物种构成和丰度分布特征,并初步探讨了水动力条件、温盐、营养盐及其他元素对束毛藻生长及分布的影响.结果表明,调查区的束毛藻种群由铁氏束毛藻(Trichodesmium thiebautii)、汉氏束毛藻(Trichodesmium hildebrandtii)和红海束毛藻(Trichodesmium erythraeum)组成,前者分布最为普遍,检出率100％,丰度最大.1996年5月束毛藻平均藻丝体密度为44.55×102 filaments/m3,铁氏束毛藻占91％,在吕宋海峡密集,总体呈现西南高,东北低的分布态势.1997年7月束毛藻平均藻丝体密度为152.72×102 filaments/m3,铁氏束毛藻占99％,除吕宋海峡外,台湾东北部海域为次高值区,总体呈现西南高,中部和东部低的分布态势.较之邻近海区结果,台湾岛以东黑潮及邻近海域的束毛藻平均藻丝体密度高于太平洋赤道热带海域、南黄海和东海陆架区、东海产卵场,低于台湾海峡西侧20 m以浅和东海低氧区.在台湾岛以东海域,束毛藻的丰度分布由其特定的地理位置和黑潮流向所决定,高温高盐的黑潮水系利于束毛藻的增殖,束毛藻的丰度分布与Fe、P等化学因子的关系有待进一步寻找证据.%The Trichodesmium population was studied based on the data of net phytoplankton from 51 sampling stations, which was carried out in the sea area east to Taiwan along with the Northwest Pacific Ocean in the cruises in May 1996 and July 1997. Total 87 samples indicated three Trichodesmium species, Trichodesmium thiebautii, Trichodesmium hildebrandtii and Trichodesmium erythraeum. Trichodesmium thiebautii accounted for the most of filament density and widely 100 % identified. The average filament density of Trichodesmium was 44.55 ×l02 filaments/m3 in May 1996, in which Trichodesmium thiebautii accounted for 91 %. The horizontal pattern of Trichodesmium filament density was higher in the southwest, lower in the northeast of the survey area. The peak assemblage area was in the Luzon Strait. The average filament density of Trichodesmium was 152.72 ×l02 filaments/m3 in July 1997, in which Trichodesmium thiebautii accounted for 99 %. The horizontal pattern of Trichodesmium filament density was higher in the southwest, lower in the east and middle of the survey area. The sub-peak assemblage area was in the northeast of Taiwan Sea besides the peak in Luzon Strait. Based on the comparison of it between the sea area east to Taiwan Island and its adjacent waters, Trichodesmium filament density in the survey area was much larger than those in the tropic sea area in Equator Pacific, waters over continental shelves of the South Yellow Sea and the East China Sea and the spawning ground in the East China Sea, while lower than those in 20-meter depth region of the Western Taiwan Strait and the low oxygen area in the East China Sea. The distribution of Trichodesmium in sea area east to Taiwan Island was decided by its geological location and Kuroshio Current. High water temperature and salinity were propitious to the growth of Trichodesmium. The author also discussed and summarized the influences of hydrodynamics, water temperature and salinity, nutrients and other chemical elements on the growth and distribution of Trichodesmium.