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Updated: Feb 4, 2026
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Biology of Microbial Communities - Interview
Published on: May 28, 2007
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Distinct changes in riparian sediment microbial communities with depth and time since dam removal
Eric R Moore1, Md Moklesur Rahman2, Joseph G Galella2
1Plant & Soil Sciences, University of Delaware, 152 Townsend Hall, 531 South College Avenue, Newark, DE, 19716, USA. ermoore@udel.edu.
Scientific Reports
|February 2, 2026
Summary
Dam removal alters riparian microbes, shifting nitrogen-cycling bacteria to deeper sediments and reducing carbon-cycling microbes over time. This impacts ecosystem recovery and biogeochemical functions.
Area of Science:
- Ecology
- Environmental Microbiology
- Biogeochemistry
Background:
- Microbes are crucial for ecosystem biogeochemical processes, particularly carbon (C) and nitrogen (N) cycling.
- Dam construction significantly alters riparian ecosystems, but microbial responses in sediments post-dam removal are poorly understood.
Purpose of the Study:
- To investigate changes in riparian microbial community composition with sediment depth and over time following dam removal.
- To assess the influence of sediment physico-chemical properties on microbial communities after dam breach.
Main Methods:
- Analyzed microbial community structure across 12 riparian sites with varying years since dam breach (0-234 years).
- Collected sediment samples at 0.3 m intervals to a depth of 4 m.
- Correlated microbial community composition with sediment physico-chemical properties.
Main Results:
- Aerobic nitrogen-cycling taxa (e.g., Nitrospirota) increased in deeper sediments with time since dam breach.
- Anaerobic carbon-cycling and iron-reducing taxa (e.g., Bathyarchaeia, Anaerolineaceae, Sva0485) dominated deeper, anoxic sediments but declined rapidly post-dam breach.
- Sediment depth and time since dam removal were key drivers of microbial community structure.
Conclusions:
- Riparian microbial communities undergo significant shifts in composition and function following dam removal.
- These microbial dynamics influence the restoration of biogeochemical cycling in recovering riparian ecosystems.
- Understanding these microbial trends is vital for predicting and managing ecosystem recovery after dam removal.
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