Diversity and Distribution of Microzooplankton Tintinnid (Ciliata: Protozoa) in the Core Region of Indian Sundarban Wetland

The study first investigated the spatial distribution, diversity, and biomass of the planktonic choreotrich ciliate tintinnids inhabiting the biosphere reserve, the core region of Indian Sundarban mangrove wetland. A total of 21 species (eight genera and six families) were recorded including agglomerated and non-agglomerated or hyaline forms from these intricate estuarine network systems. Maximum mean abundance (2747 +/- 111 individuals L-1) and species diversity (H' = 2.32) of tintinnid ciliate were recorded at the sampling site located towards the Bay of Bengal whereas lower abundance (666 +/- 56 individuals L-1) and diversity (H' = 1.55) were encountered towards inner part of the estuary. Tintinnopsis represented the most dominant agglutinated genus comprising of Tintinnopsis beroidea, Tintinnopsis fimbriata, Tintinnopsis cylindrica, Tintinnopsis tocantinensis, and Tintinnopsis radix, accounting similar to 52% of total tintinnid community. The agglomerated forms Amphorellopsis tetragona, Eutintinnus apertus, Codonellopsis lusitanica, and T. fimbriata were recorded for the first time in this region. The biomass value exhibited wide range of variations (0.03 +/- 0.09 to 12.4 +/- 1.1 mu gCL(-1)), accounting maximum value towards seaward region. The small-sized tintinnid (lorica length <40 mu m) contributed the most dominant group (sharing similar to 85% of total species abundance) in this core region and their presence was mainly governed by factors, namely, chlorophyll alpha, salinity, and nutrients (nitrate and silicate). The results of combining multivariate methods (RELATE and BIOENV analyses) reveal that chl a and nitrate were the potential significant factors for tintinnid abundance and distribution.