Surya Balakrishnan and Boobal Rangaswamy and Lathika Shanmugam (2026) Ecogenomic profiling of spatial variations in sediment microbial communities of a freshwater lake. Ecogenomic profiling of spatial variations in sediment microbial communities of a freshwater lake, 5: 100214. pp. 1-11. ISSN 2950-2632

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Abstract

Freshwater lake sediments integrate physicochemical conditions and provide sensitive indicators of spatial
variation in microbial community structure. This study investigated sediment bacterial communities from four
sites in Singanallur Lake, Coimbatore, using 16S rRNA V3–V4 amplicon sequencing to characterize spatial
heterogeneity in sediment microbial communities under uniform seasonal conditions. Across all samples, a total
of 44 phyla, 114 classes, 257 orders, 466 families, and 1107 genera were detected, reflecting high taxonomic
richness and spatial variability within the lake sediments. The community was dominated by Pseudomonadota,
which ranged from 80.9 % in S1–51.8 % in S4, followed by Bacillota, Bacteroidota, and Cyanobacteriota. At the
genus level, Caulobacter decreased from 30.6 % in S1–12.5 % in S4, along with notable genera such as Bosea and
Phreatobacter. Alpha diversity increased steadily from S1 to S4, with observed OTUs ranging from 1722 to 13,796
and Shannon index values increasing from 5.14 to 8.44. Sequencing coverage ranged from 0.34 to 0.74, indi�cating incomplete sampling depth and representing a methodological limitation, while Gini coefficients
(0.64–0.83) reflected uneven community structures, particularly in S1. Several low-abundance and site-enriched
genera, including Akkermansia, Helicobacter, and Candidatus Saccharimonas, showed localized enrichment, indi�cating site-specific environmental conditions within the lake. Venn diagram analysis showed a core of five shared
genera representing 31.3 % of total abundance, while rare and unique taxa exhibited minimal overlap (4.0 % and
3.8 %), highlighting strong spatial differentiation among sampling sites. Heatmap-based multivariate analysis
integrating microbial OTU abundance with measured physicochemical water quality parameters and sediment
heavy metal concentrations revealed clear associations between microbial assemblages and localized environ�mental gradients. These patterns indicate that sediment microbial communities respond sensitively to present�day physicochemical heterogeneity within the lake. This study provides a baseline spatial ecogenomic frame�work for Singanallur Lake and highlights the value of integrating microbial community profiling with water
quality and metal measurements for future monitoring and comparative assessments

Item Type: Article
Uncontrolled Keywords: Keywords: Microbiome Microbiota Anthropogenic Bioindicators Abundance Gini coefficient
Divisions: PSG College of Arts and Science > Department of Biotechnology
Depositing User: Dr. B Sivakumar
Date Deposited: 01 Apr 2026 09:43
Last Modified: 01 Apr 2026 09:43
URI: https://ir.psgcas.ac.in/id/eprint/2768

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