Diatom assemblage changes in agricultural alluvial plain streams and application for nutrient management

Journal of Environmental Quality
By:  and 



In large, alluvial floodplains dominated by agriculture, small streams have the potential to experience nutrient enrichment affecting algal assemblage structure and metabolism. Nutrient enrichment is largely driven by application of nutrients and altered hydrologic regimes. To inform stressor–response-based nutrient reduction goals for agricultural alluvial plain streams, diatom assemblages were sampled from 25 streams located within the Mississippi Alluvial Plain (MAP) with various land management practices and associated P and N inputs. From August through September 2015, epidendric diatom assemblage samples were collected from instream woody debris. Field nutrient gradients were skewed toward higher concentrations, and ranges of previously reported diatom assemblage response thresholds indicative of oligotrophic conditions were not well represented. Ordination analysis identified a gradient in species composition associated with increasing P and decreasing dissolved oxygen. A significant shift in diatom assemblage structure occurred when total P concentrations in the MAP streams exceeded 0.12 mg L−1. Phosphorus-enriched systems were represented by a distinct set of indicator species, lower abundances of ubiquitous species, greater abundances of highly tolerant species, and greater abundances of high-P indicator species. No relationships were observed among diatom assemblage measures or traits with increasing N. Current results do not address potential criteria for identifying high-quality, oligotrophic streams. However, measures of diatom assemblage structure have potential for helping set benchmarks to reduce nutrient impacts and monitor effects of agricultural best management practices on MAP streams.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Diatom assemblage changes in agricultural alluvial plain streams and application for nutrient management
Series title Journal of Environmental Quality
DOI 10.2134/jeq2018.05.0196
Volume 48
Issue 1
Year Published 2019
Language English
Publisher ACSESS
Contributing office(s) Lower Mississippi-Gulf Water Science Center
Description 10 p.
First page 83
Last page 92
Country United States
Other Geospatial Yazoo River basin
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