Tintinnid community structure in the eastern equatorial Indian Ocean during the spring inter‑monsoon period

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 sizeclasses 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.

The Horizontal Distribution of Siliceous Planktonic Radiolarian Community in the Eastern Indian Ocean

“…This strengthens the possibility of using Chl-a remote sensing data to estimate the geographic distributions of radiolarian in the Ocean. These concentration values often lead to low nutrients in the DCM layer in spring [29,31]. Our findings also confirmed earlier reports that low nutrients at the equator correspond to the DCM (deep Chl a concentration maximum) layer from 50 to 100 m in a same study area [29].…”

“…Our findings also confirmed earlier reports that low nutrients at the equator correspond to the DCM (deep Chl a concentration maximum) layer from 50 to 100 m in a same study area [29]. This DCM chlorophyll a maximum has caused the dominance of nano and picoplankton biomass [29,31] including some heterotrophs bacteria [73] in the region. The silicate, nitrate or oxygen concentrations including chlorophyll a in surface water are mostly highly correlated at the transects of 80 • E and equator (Table 4).…”

“…These concentration values often lead to low nutrients in the DCM layer in spring [29,31]. Our findings also confirmed earlier reports that low nutrients at the equator correspond to the DCM (deep Chl a concentration maximum) layer from 50 to 100 m in a same study area [29]. This DCM chlorophyll a maximum has caused the dominance of nano and picoplankton biomass [29,31] including some heterotrophs bacteria [73] in the region.…”

“…Temperature and salinity are not sufficient explanatory variables: Chlorophyll a and nutrients and dissolved organic matter (DOM) can stimulate heterotrophic communities such as the radiolarian [4,27,71,72], tintinnid [29] and diazotroph communities [73,74]. These environmental variables play an important role in circulatory changes of EIO in the spring season.…”

Progress in studies on the diversity and distribution of planktonic ciliates (Protista, Ciliophora) in the South China Sea

“…For instance, studies have focused on European waters, such as the Baltic (e.g., Mironova et al 2009) and the Mediterranean Seas (e.g., Bachy et al 2014;Dolan 2000;Pitta and Giannakourou 2000); waters of North America, in particular the New England Shelf (e.g., Grattepanche et al 2015;Santoferrara et al 2014); and across the Southwestern Atlantic Shelf (e.g., Thompson and Alder 2005;Thompson et al 2001). In addition, some investigations Edited by Jiamei Li. of biogeography at an oceanic scale have been conducted in Atlantic (e.g., Rychert et al 2014), Pacific (e.g., Gómez 2007;Sohrin et al 2010) and Indian Oceans (e.g., Zhang et al 2017). Moreover, the global diversity patterns of ciliates have been studied during the Tara Oceans Voyage (Gimmler et al 2016).…”