台湾海峡微微型浮游植物的生态研究 Ⅱ. 类群组成、生长速率及其影响因子

1997年8月、1998年2～3月和1998年8月,应用荧光显微镜、14C法分别测定了台湾海峡微微型浮游植物的类群组成和生长速率,探讨了该海域原绿球藻的存在及丰度问题.结果表明,在类群的丰度组成上,该海域以含藻红素的蓝细菌(PE细胞)占优势,平均为83%～93%(航次平均范围,下同),微微型真核浮游植物(EU细胞)次之,平均为7%～11%,含藻蓝素的蓝细菌(PC细胞)最少,平均为0%～6%;在碳生物量的组成上,PE细胞仍占优势,但其贡献率降低(52%～74%),EU细胞所占比例则升高(26%～44%).台湾海峡微微型浮游植物生长速率的变异性较大(0.52～2.25d-1),这可能与其所在测站的环境异质性(如营养盐的差异等)有关.采用叶绿素估算法证实该海域存在原绿球藻,其丰度介于107～108个/dm3之间,若将此考虑在内,在类群的丰度和生物量组成上,原绿球藻占优势(1998年8月碳生物量贡献率除外,为22%),丰度贡献率为63%～99%,碳生物量贡献率为60%～94%.

Ecological study on picophytoplankton in the Taiwan Strait Ⅱ . Group composition, growth rate and its affecting factors

The studies on the composition, growth rate and environmental controlling were car ried out during three cruises in the Taiwan Strait (August 1997, February-March 1998 and August 1998) using epifluorescence microscopy and ¹⁴C-radio tracer.The results show that phycoerythrin-rich cyanobacteria (PE) dominate in abundance (contributed 83%~93%), picoeukaryotes (EU) are second and phycocyanin-rich cyanobacteria (PC) are the least abundant.With carbon biomass, PE still predominates although the contribution goes down (52%~74%), EU's contribution increases up to 26%~44%.Growth rate of picophy toplankton varies from 0.52 to 2.25 d^-1, which may be due to different environmental parameters (e.g., nutrients) in the study area.Prochlorococcus may occur in the Taiwan Strait by using chl.a evaluation, its abundance ranges between 10⁷ and 10⁸ cell/dm³, Prochlorococcus dominate the picophytoplankton both in abundance and biomass if included in picophytoplankton in the Taiwan Strait in August 1997, and February-March 1998, however, cyanobacteria dominate in carbon biomass in August 1998.