Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal Sediments

Aquatic ecosystems, including rivers, estuaries, and coastal environments, are crucial for maintaining biodiversity, regulating nutrient cycles, and supporting human livelihoods. However, these ecosystems are increasingly being threatened by urbanization, making it essential to understand their micr...

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Main Authors: Ramganesh Selvarajan, Ming Yang, Henry J. O. Ogola, Timothy Sibanda, Akebe Luther King Abia
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Diversity
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Online Access:https://www.mdpi.com/1424-2818/16/12/749
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author Ramganesh Selvarajan
Ming Yang
Henry J. O. Ogola
Timothy Sibanda
Akebe Luther King Abia
author_facet Ramganesh Selvarajan
Ming Yang
Henry J. O. Ogola
Timothy Sibanda
Akebe Luther King Abia
author_sort Ramganesh Selvarajan
collection DOAJ
description Aquatic ecosystems, including rivers, estuaries, and coastal environments, are crucial for maintaining biodiversity, regulating nutrient cycles, and supporting human livelihoods. However, these ecosystems are increasingly being threatened by urbanization, making it essential to understand their microbial communities and their ecological roles. This study employed high-throughput 16S rRNA gene sequencing to characterize the bacterial communities within the riverine, estuarine, and coastal sediments of Adyar Creek, Chennai, India. Proteobacteria were the dominant phylum across most samples, with proportions ranging from 39.65% to 72.09%. Notably, the estuarine environment exhibited a distinct taxonomic profile characterized by a significant abundance of Firmicutes (47.09% of the bacterial population). Distinct bacterial classes were observed across sediment types: Alphaproteobacteria (30.07–34.32%) in riverine sediments, Bacilli dominated estuarine sediments (40.17%), and Gammaproteobacteria (15.71–51.94%) in coastal sediments. The most significant environmental factors influencing the bacterial community composition across these samples were pH, salinity, phosphate, and nitrate. LEfSe (Linear discriminant analysis Effect Size) analysis identified specific genera within the estuary, including <i>Bacillus</i> (20.26%), unclassified_<i>Paenibacillus</i> (12.87%), <i>Clostridium</i> (3.81%), <i>Gailella</i> (3.17%), <i>Paenibacillus</i> (3.02%), <i>Massilia</i> (1.70%), <i>Paraburkholderia</i> (1.42%), and <i>Pantoea</i> (1.15%), as potential biomarkers for habitat health. Functional analysis revealed an elevated expression of the genes associated with ABC transporters and carbon metabolism in the estuary, suggesting a heightened nutrient cycling capacity. Furthermore, co-occurrence network analysis indicated that bacterial communities exhibit a strong modular structure with complex species interactions across the three sediment types. These findings highlight bacterial communities’ critical role and the key drivers in estuarine ecosystems, establishing a baseline for further investigations into the functional ecology of these vulnerable ecosystems.
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spelling doaj-art-ca5378de855044a7a1446ce6df856cd82025-08-20T02:00:21ZengMDPI AGDiversity1424-28182024-12-01161274910.3390/d16120749Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal SedimentsRamganesh Selvarajan0Ming Yang1Henry J. O. Ogola2Timothy Sibanda3Akebe Luther King Abia4Department of Environmental Sciences, College of Agriculture and Environmental Sciences (CAES), University of South Africa, Florida Campus, Roodepoort 1709, South AfricaInstitute of Deep-Sea Science and Engineering (IDSSE), Chinese Academy of Sciences (CAS), Sanya 572000, ChinaDepartment of Environmental Sciences, College of Agriculture and Environmental Sciences (CAES), University of South Africa, Florida Campus, Roodepoort 1709, South AfricaSchool of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South AfricaAntimicrobial Research Unit, College of Health Sciences, University of KwaZulu-Natal, Durban 4000, South AfricaAquatic ecosystems, including rivers, estuaries, and coastal environments, are crucial for maintaining biodiversity, regulating nutrient cycles, and supporting human livelihoods. However, these ecosystems are increasingly being threatened by urbanization, making it essential to understand their microbial communities and their ecological roles. This study employed high-throughput 16S rRNA gene sequencing to characterize the bacterial communities within the riverine, estuarine, and coastal sediments of Adyar Creek, Chennai, India. Proteobacteria were the dominant phylum across most samples, with proportions ranging from 39.65% to 72.09%. Notably, the estuarine environment exhibited a distinct taxonomic profile characterized by a significant abundance of Firmicutes (47.09% of the bacterial population). Distinct bacterial classes were observed across sediment types: Alphaproteobacteria (30.07–34.32%) in riverine sediments, Bacilli dominated estuarine sediments (40.17%), and Gammaproteobacteria (15.71–51.94%) in coastal sediments. The most significant environmental factors influencing the bacterial community composition across these samples were pH, salinity, phosphate, and nitrate. LEfSe (Linear discriminant analysis Effect Size) analysis identified specific genera within the estuary, including <i>Bacillus</i> (20.26%), unclassified_<i>Paenibacillus</i> (12.87%), <i>Clostridium</i> (3.81%), <i>Gailella</i> (3.17%), <i>Paenibacillus</i> (3.02%), <i>Massilia</i> (1.70%), <i>Paraburkholderia</i> (1.42%), and <i>Pantoea</i> (1.15%), as potential biomarkers for habitat health. Functional analysis revealed an elevated expression of the genes associated with ABC transporters and carbon metabolism in the estuary, suggesting a heightened nutrient cycling capacity. Furthermore, co-occurrence network analysis indicated that bacterial communities exhibit a strong modular structure with complex species interactions across the three sediment types. These findings highlight bacterial communities’ critical role and the key drivers in estuarine ecosystems, establishing a baseline for further investigations into the functional ecology of these vulnerable ecosystems.https://www.mdpi.com/1424-2818/16/12/749estuarine ecosystemsriverine systemssedimentbacterial diversitynext-generation sequencingecosystem function
spellingShingle Ramganesh Selvarajan
Ming Yang
Henry J. O. Ogola
Timothy Sibanda
Akebe Luther King Abia
Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal Sediments
Diversity
estuarine ecosystems
riverine systems
sediment
bacterial diversity
next-generation sequencing
ecosystem function
title Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal Sediments
title_full Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal Sediments
title_fullStr Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal Sediments
title_full_unstemmed Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal Sediments
title_short Evaluating the Impact of Environmental Factors on Bacterial Populations in Riverine, Estuarine, and Coastal Sediments
title_sort evaluating the impact of environmental factors on bacterial populations in riverine estuarine and coastal sediments
topic estuarine ecosystems
riverine systems
sediment
bacterial diversity
next-generation sequencing
ecosystem function
url https://www.mdpi.com/1424-2818/16/12/749
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