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Temperature and Nitrogen Effects on Phosphorus Uptake by Agricultural Stream‐Bed Sediments
Author(s) -
McDowell Richard W.,
Elkin Kyle R.,
Kleinman Peter J.A.
Publication year - 2017
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2016.09.0352
Subject(s) - environmental science , sediment , phosphorus , abiotic component , baseflow , surface runoff , biomass (ecology) , nutrient , nitrogen , eutrophication , hydrology (agriculture) , environmental chemistry , water quality , streams , agronomy , streamflow , chemistry , ecology , drainage basin , biology , geology , paleontology , computer network , cartography , geotechnical engineering , organic chemistry , computer science , geography
Climate change will likely increase the growing season, temperatures, and ratio of nitrogen (N) to phosphorus (P) loss from land to water. However, it is unknown how these factors influence P concentrations in streams. We sought to evaluate differences in biotic and abiotic processes affecting stream sediment P dynamics under different temperature and N‐enrichment regimes. Three sediments of varying P composition and sorption characteristics were placed into a fluvarium. Synthetic runoff water, with or without added N, was added to the flume's reservoir, and the solution was maintained at 19 or 26°C. Water and sediment samples were taken with time since runoff was introduced. The rate and magnitude of P uptake by sediment was greater at 19°C compared with 26°C, and also when N was added compared with no N added. Analysis of sediment samples indicated that P uptake via abiotic processes was greater at 19 than at 26°C. The addition of N stimulated P uptake by the microbial biomass at 19°C, but microbial uptake was potentially inhibited at 26°C. Because microbial biomass is a temporary store of P, these data suggest that more P may be available with increasing temperatures during the growing season, especially under baseflow, implying that strategies to mitigate P losses from land to water should be strengthened to prevent potential water quality impairment. Core Ideas Climate change will boost stream temperatures, N inputs, and P limitation of algae. P uptake from runoff was greater at 19°C with added N than at 26°C without N. Uptake at 19°C was attributed to sorption, but also to the microbial biomass. Uptake by microbial biomass at 26°C was inhibited and P may be released. Climate change may increase baseflow P requiring runoff inputs to be better mitigated.