ABSTRACT: Tintinnid community structure was investigated by plankton net (20 µm) sampling in the water column (0-200 m) at 33 stations during the spring inter-monsoon (10 March to 9 April 2012) in the eastern equatorial Indian Ocean. A total of 126 species belonging to 32 genera were recorded. Tintinnid abundance and biomass in the range of 193-2983 ind. m^–3 and 0.99-14.75 µg C m^–3 were positively related to integrated chlorophyll a (chl a) concentration. Taxonomic and morphological diversity were not significantly related to integrated chl a concentration and size diversity, estimated by size-fractionated chl a concentration in the water column of 0-200 m, but were negatively correlated to the depth of the deep chlorophyll maximum. Species abundance distributions at most stations (31 of 33) and in the 3 zones—the northern zone of the equator, the southern zone of the equator (SEQ) and the equator (EQ)—followed a typical lognormal distribution. The geometric distribution gave the best fit for the distribution of lorica oral diameter size-classes in the NEQ and SEQ. Our results suggest that the community structure of tintinnids is governed by the underlying water column environment rather than by the neutral theory of random colonization from a large species pool.

中文翻译：

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春季季风间隔期赤道印度洋东部的丁丁尼德群落结构

摘要：在春季季风间（2012年3月10日至4月9日），在赤道东印度洋，通过33个站的水柱（0-200 m）中的浮游生物网（20 µm）采样，对Tintinnid群落结构进行了调查。记录了属于32属的126种。Tintinnid的丰度和生物量在193-2983 ind范围内。m ^–3和0.99-14.75 µg C m ^–3与综合叶绿素a（chl a）浓度呈正相关。分类学和形态学多样性与整合的chl a浓度和大小多样性没有显着相关性（通过大小分级的chl a估算）水柱中的浓度为0-200 m，但与深叶绿素最大值的深度呈负相关。在大多数站点（33个站点中的31个站点）和3个区域（赤道的北部区域，赤道的南部区域（SEQ）和赤道（EQ））中，物种的丰度分布遵循典型的对数正态分布。几何分布最适合NEQ和SEQ中口头直径大小类别的分布。我们的结果表明，tintinnids的群落结构由潜在的水柱环境控制，而不是由大型物种库中的随机定殖的中性理论控制。