Bacterial distribution in Twilight zone of the Indian sector of Southern Ocean: V3- V4 rDNA hypervariable region data

Twilight zones in oceans represent the oceanic waters between 200 m to 1000 m in depth, wherein sunlight is diffused and intensity is < 1% of surface value. The activities and diversity of marine micro-organisms in this unique zone are understudied, especially in the Indian Sector of the Southern Ocean. For a better understanding of the microbial environment and diversity in the twilight zone of the Indian sector of Southern Ocean, samples were collected from 200m depth in eddy-influenced waters of Subtropical Front (STF), Sub-Antarctic Front (SAF), Polar Front (PF), waters off Kerguelen (Kw), and Prydz Bay (Pb) waters. In this article, next generation sequencing (NGS) based amplicon data of 16s rDNA bacterial samples are presented. Hypervariable V3-V4 regions were sequenced using Hiseq platform, and data was processed using Mothur v 1.48.0, and database Silva 138.1nr. Total of nine different phyla is reported from the Southern Ocean at 200m, whereas at order level Synechococcales was found in STF waters only and SAR 11_ Clades were present in all stations.Twilight zones in oceans represent the oceanic waters between 200 m to 1000 m in depth, wherein sunlight is diffused and intensity is < 1% of surface value. The activities and diversity of marine micro-organisms in this unique zone are understudied, especially in the Indian Sector of the Southern Ocean. For a better understanding of the microbial environment and diversity in the twilight zone of the Indian sector of Southern Ocean, samples were collected from 200m depth in eddy-influenced waters of Subtropical Front (STF), Sub-Antarctic Front (SAF), Polar Front (PF), waters off Kerguelen (Kw), and Prydz Bay (Pb) waters. In this article, next generation sequencing (NGS) based amplicon data of 16s rDNA bacterial samples are presented. Hypervariable V3-V4 regions were sequenced using Hiseq platform, and data was processed using Mothur v 1.48.0, and database Silva 138.1nr. Total of nine different phyla is reported from the Southern Ocean at 200m, whereas at order level Synechococcales was found in STF waters only and SAR 11_ Clades were present in all stations. (c) 2022 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Automated summary

Twilight zones in oceans, specifically in the Indian Sector of the Southern Ocean, have been understudied in terms of microbial activities and diversity. This study collected samples from the depths of 200m in different eddy-influenced waters to better understand the microbial environment in this unique zone. The sequencing data of bacterial samples showed the presence of nine different phyla, with Synechococcales found only in STF waters and SAR 11_ Clades present in all stations.