Related Experiment Video
Updated: Sep 25, 2025
09:38
Understanding Dissolved Organic Matter Biogeochemistry Through In Situ Nutrient Manipulations in Stream Ecosystems
Published on: October 29, 2016
10.5K
Quantifying stream periphyton assemblage responses to nutrient amendments with a molecular approach
James D Hagy Iii1,2, Katelyn A Houghton1,3, David L Beddick1,4
1United States Environmental Protection Agency, Center for Environmental Measurement and Modeling, Gulf Environmental Measurement and Modeling Division, 1 Sabine Island Drive, Gulf Breeze, Florida 32561 USA.
Freshwater Science (Print)
|May 2, 2022
Summary
Nutrient pollution impacts stream health. Molecular analysis of periphyton reveals microbial community shifts, with diatoms showing strong phosphorus responses, aiding water quality assessment.
Area of Science:
- Environmental Microbiology
- Aquatic Ecology
- Molecular Ecology
Background:
- Nutrient pollution (nitrogen and phosphorus) is a major water quality issue in US streams.
- Biological indicators like macroinvertebrates and periphyton are used to assess nutrient impacts.
- Molecular methods analyzing diverse periphyton assemblages offer enhanced bioindicator potential.
Purpose of the Study:
- To assess the utility of broad periphyton assemblage evaluation for stream bioindicators.
- To investigate in situ nutrient responses of different periphyton groups using molecular techniques.
- To compare nutrient effects in streams with varying agricultural land use.
Main Methods:
- In situ nutrient-diffusing substrate experiments with nitrogen and phosphorus amendments.
- Analysis of periphyton microbial assemblage composition using 16S and 18S rRNA gene sequencing.
- Deployment in two southeastern US streams with differing agricultural land use.
Main Results:
- Periphyton assemblages varied significantly by stream, season, and nutrient treatment.
- Nutrient amendment effects were more pronounced in the stream with lower nutrient loading.
- Combined N and P amendments reduced bacterial and archaeal species richness and evenness.
- Diatoms showed a stronger response to phosphorus than nitrogen.
Conclusions:
- In situ nutrient-diffusing substrate experiments effectively describe periphyton responses to nutrients.
- Molecular approaches analyzing diverse periphyton assemblages can enhance stream bioindicators.
- Findings support environmental agencies in assessing and managing stream water quality.
