Geochemical factors impacting nitrifying communities in sandy sediments
Stephanie J Wilson1,2, Bongkeun Song1, Iris C Anderson1
1Department of Biological Sciences, Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia, USA.
Environmental Microbiology
|September 16, 2023
Summary
Sandy sediment beaches host vital microbial communities in subterranean estuaries (STEs). Geochemical factors like dissolved oxygen and nitrogen influence these microbes, impacting nutrient cycling in coastal waters.
Area of Science:
- Marine microbial ecology
- Biogeochemistry
- Coastal ecosystem dynamics
Background:
- Sandy beaches are crucial for nutrient cycling, with subterranean estuaries (STEs) acting as biogeochemical hotspots.
- The microbial community within STEs plays a key role in processing nutrients, particularly nitrogen (N), from groundwater inputs.
- Nitrification is a critical process in STEs, transforming nitrogen compounds and influencing their removal or transport.
Purpose of the Study:
- To characterize the spatial and temporal variation of microbial communities and nitrifying organisms in STEs.
- To investigate the influence of geochemical parameters on the distribution and abundance of nitrifiers within STEs.
- To understand the link between microbial community structure, nitrifier abundance, and nutrient cycling in sandy beach ecosystems.
Main Methods:
- Metabarcoding of 16S rRNA genes to analyze microbial community structure.
- Quantitative PCR (qPCR) of ammonia monooxygenase (amoA) genes to quantify nitrifier abundance.
- Analysis of geochemical parameters including dissolved oxygen, salinity, pH, dissolved inorganic carbon, and dissolved inorganic nitrogen (DIN).
Main Results:
- Sediment microbial communities showed significant variation with depth and correlated with geochemical gradients (dissolved oxygen, salinity, pH, dissolved inorganic carbon, DIN).
- The genetic potential for nitrification was confirmed by the presence and quantification of amoA genes.
- Ammonia oxidizer abundance was primarily explained by dissolved inorganic nitrogen (DIN), dissolved oxygen (DO), and pH.
Conclusions:
- Geochemical gradients are key drivers of STE microbial community composition and nitrifier abundance.
- Understanding these microbial dynamics is essential for predicting the fate and transport of groundwater-derived nutrients to coastal environments.
- This research highlights the ecological significance of STEs in coastal nutrient management and ecosystem health.
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