Surreal illustration of sulfate-reducing bacteria in reservoir sediment.

Unlocking Reservoir Secrets: How Bacteria Can Save Our Drinking Water

Beau Callahan in Climate & Environment June 2025 • 4 min read.

"Dive into the hidden world of sulfate-reducing bacteria and discover their crucial role in maintaining the health of our water reservoirs and ensuring safer drinking water for all."

Clean and accessible freshwater is the lifeblood of urban communities, and reservoirs play a vital role in providing this essential resource. However, these aquatic ecosystems face increasing threats from eutrophication and pollution, jeopardizing water quality and posing risks to public health. Sediments within these reservoirs act as both a sink and a source of nutrients and contaminants, making it crucial to understand the complex microbial processes occurring within them.

Among these processes, sulfate reduction stands out as a key player in the biogeochemical cycling of reservoirs. Sulfate-reducing bacteria (SRB) thrive in the oxygen-depleted sediments, breaking down organic matter and influencing the release of various substances into the water column. While their presence is well-documented in marine environments, their role in freshwater drinking water reservoirs remains less explored.

A new study focusing on the Zhou Cun drinking water reservoir in Eastern China is shedding light on the diversity, abundance, and activity of SRB in these vital ecosystems. By analyzing sediment samples from various sites within the reservoir, researchers are uncovering valuable insights into how these microorganisms impact water quality and what strategies can be employed to manage them effectively.

The Hidden World of Sulfate-Reducing Bacteria

Surreal illustration of sulfate-reducing bacteria in reservoir sediment.

The Zhou Cun reservoir, like many freshwater systems, faces the challenge of maintaining water quality amidst agricultural and urban runoff. The research team meticulously collected sediment samples across different sites in the reservoir during April and June 2012 to analyze the SRB communities. The team used a combination of methods, including most-probable-number (MPN) counts, PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis), and gene sequencing to investigate SRB populations and their diversity. They also correlated SRB presence with Sediment quality.

The study revealed that the deepest sampling site had the highest levels of acid-volatile sulfide (AVS). This is significant because AVS is a byproduct of SRB activity, suggesting a thriving population of these bacteria in that area. The highest MPN estimate, indicating the most SRB, was found in May at the deepest sampling site, further supporting this conclusion. Analysis of the genetic material (dsrB gene) from the SRB showed variations across different sampling locations and times, indicating a diverse community influenced by environmental factors.

Here’s what the study revealed about sulfate-reducing bacteria (SRB) in the Zhou Cun drinking water reservoir:

SRB abundance varied with sampling site and date, with the highest counts found at the deepest site in May.
Dominant SRB species included Desulfobulbus sp., Desulfobacterium sp., and several uncultured strains.
Organic matter, nitrogen, and phosphorus levels significantly correlated with SRB community diversity.
The study provides insights into SRB’s role in freshwater reservoirs, contributing to improved water quality management.

Organic matter and nutrient concentrations (nitrogen and phosphorus) strongly influenced the diversity of SRB communities. This finding highlights the intricate relationship between environmental factors and microbial life in reservoir sediments. These details offer a more profound understanding of microbial dynamics in freshwater ecosystems. As water management strategies evolve, a deeper comprehension of these microbial processes is critical to protecting our drinking water resources. The link to organic matter and nutrients is key to future efforts to manage water quality.

Future Directions: Harnessing SRB for Water Quality

The Zhou Cun reservoir study provides a crucial foundation for future research and management strategies. By understanding the complex interplay between SRB, sediment composition, and water quality, we can explore innovative approaches to improve reservoir health. This includes optimizing nutrient management practices to minimize organic matter accumulation, exploring bioremediation strategies using SRB to remove pollutants, and implementing water circulation techniques to prevent stratification and promote oxygenation. Through continued research and collaboration, we can unlock the full potential of these microbial communities to safeguard our precious water resources.

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This article is based on research published under:

DOI-LINK: 10.4238/2015.may.29.15, Alternate LINK

Title: Abundance And Diversity Of Sulfate-Reducing Bacteria In The Sediment Of The Zhou Cun Drinking Water Reservoir In Eastern China

Subject: Genetics

Journal: Genetics and Molecular Research

Publisher: Genetics and Molecular Research

Authors: X. Yang, T.L. Huang, L. Guo, C. Xia, H.H. Zhang, S.L. Zhou

Published: 2015-01-01

Everything You Need To Know

What exactly are sulfate-reducing bacteria, and what is their significance in freshwater reservoirs?

Sulfate-reducing bacteria, or SRB, are microorganisms that thrive in oxygen-depleted environments, such as the sediments of freshwater reservoirs. They play a crucial role in biogeochemical cycling by breaking down organic matter and influencing the release of various substances into the water. The Zhou Cun reservoir study highlights their presence and activity in drinking water reservoirs, showcasing their importance in maintaining water quality.

What specific methodologies were employed in the Zhou Cun reservoir study to examine sulfate-reducing bacteria?

The Zhou Cun reservoir study used several methods to investigate SRB populations. These included most-probable-number (MPN) counts to estimate SRB abundance, PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) to analyze SRB community diversity, and gene sequencing to identify specific SRB species. Researchers also correlated SRB presence with sediment quality parameters to understand the environmental factors influencing their distribution and activity.

How do organic matter, nitrogen, and phosphorus levels influence the diversity of sulfate-reducing bacteria communities?

In the Zhou Cun reservoir study, organic matter, nitrogen, and phosphorus levels were found to significantly correlate with SRB community diversity. Higher concentrations of organic matter and nutrients promote SRB growth and activity, leading to shifts in the composition of SRB communities. Managing these nutrient levels is crucial for controlling SRB activity and maintaining water quality. If left unmanaged, eutrophication may occur leading to algal blooms.

Where were the highest levels of acid-volatile sulfide (AVS) and SRB found within the Zhou Cun reservoir, and what does this imply?

The highest levels of acid-volatile sulfide (AVS), a byproduct of SRB activity, were found at the deepest sampling site in the Zhou Cun reservoir. This indicates that the deepest areas of the reservoir provide favorable conditions for SRB, likely due to higher organic matter content and lower oxygen levels. The highest MPN estimates, indicating the most SRB, were also found at the deepest sampling site, further supporting this conclusion. This means that managing conditions in these deep areas is especially important for controlling SRB activity.

Considering the insights gained from the Zhou Cun reservoir study, what future strategies can be implemented to improve water quality using sulfate-reducing bacteria?

Future strategies involve optimizing nutrient management to minimize organic matter accumulation in reservoirs, exploring bioremediation strategies using SRB to remove pollutants, and implementing water circulation techniques to prevent stratification and promote oxygenation. Further research could investigate how specific SRB species can be leveraged to enhance pollutant removal and improve overall water quality. Understanding the dsrB gene variations and their functional implications could also provide insights into optimizing bioremediation processes using SRB in drinking water reservoirs.