Study of diatom assemblages in Sundarbans mangrove water based on light microscopy and rbcL gene sequencing

Brajogopal Samanta,Punyasloke Bhadury

doi:10.1016/j.heliyon.2018.e00663

Brajogopal Samanta, Punyasloke Bhadury

Open Access

https://doi.org/10.1016/j.heliyon.2018.e00663

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Abstract

Sundarbans, the world's largest mangrove deltaic region, is one of the most productive ecosystems in tropical and subtropical latitudes and also serve as a nursery ground for rich coastal fisheries. In this study, we highlighted diatom assemblages from the Indian part of Sundarbans Biosphere Reserve (SBR) area for the first time based on light microscopy and rbcL gene sequencing and phylogeny. In total, 15 diatom species (11 centric forms and 4 pennate forms) were documented using light microscopy, and 3 major clades of diatoms were detected in rbcL phylogeny. Out of 15 diatom species, 7 were the first record from Sundarbans mangrove water. One of the species, Thalassiosira ferelineata Hasle and Fryxell, was reported for the first time in an Asian mangrove ecosystem based on light microscopy. Our study suggests the importance of establishing cultures and their polyphasic taxonomy are the future necessity to create an authenticated diatom database from mangrove water, which is still overlooked globally.

Highlights

Marine ecosystems are key contributors of global primary production accounting for approximately 50 gigatons of carbon each year (Field et al, 1998)
Sundarbans, the world’s largest deltaic contiguous mangrove region, is situated at the estuarine phases of river Ganga, Brahmaputra and Meghna between latitudes 21320 and 21400 N and longitudes 88050 and 89 E spanning across India and Bangladesh (Spalding et al, 1997)
Diatom cell abundance at our study area ranged from 12,500 cells/L (StnSBRS1) to 23,000 cells/L (StnSBRN2) (Table 1)

Summary

Introduction

Marine ecosystems are key contributors of global primary production accounting for approximately 50 gigatons of carbon each year (Field et al, 1998). One of such productive ecosystems is mangrove ecosystem located in tropical and subtropical latitudes. This ecosystem serves as the nursery ground for rich fisheries (Robertson and Blaber, 1992). The salient features of this deltaic mangrove ecosystem include interconnected network of numerous creeks, rivers and rivulets, and semi-diurnal tidal influences across the entire region. In 1987, UNESCO declared the core mangrove forest of Indian Sundarbans (2,585 sq. km) as Sundarbans Biosphere Reserve (SBR) for protection and conservation of mangrove flora and fauna including the Royal Bengal Tiger from anthropogenic disturbances

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