Journal article
Linking terrestrial phosphorus inputs to riverine export across the United States
Water research (Oxford), Vol.124, pp.177-191
11/01/2017
Handle:
https://hdl.handle.net/2376/110389
PMCID: PMC5922462
PMID: 28756220
Abstract
Humans have greatly accelerated phosphorus (P) flows from land to aquatic ecosystems, causing eutrophication, harmful algal blooms, and hypoxia. A variety of statistical and mechanistic models have been used to explore the relationship between P management on land and P losses to waterways, but our ability to predict P losses from watersheds often relies on small scale catchment studies, where detailed measurements can be made, or global scale models that that are often too coarse-scaled to be used directly in the management decision-making process. Here we constructed spatially explicit datasets of terrestrial P inputs and outputs across the conterminous U.S. (CONUS) for 2012. We use this dataset to improve understanding of P sources and balances at the national scale and to investigate whether well-standardized input data at the continental scale can be used to improve predictions of hydrologic P export from watersheds across the U.S. We estimate that in 2012 agricultural lands received 0.19 Tg more P as fertilizer and confined manure than was harvested in major crops. Approximately 0.06 Tg P was lost to waterways as sewage and detergent nationally based on per capita loads in 2012. We compared two approaches for calculating non-agricultural P waste export to waterways, and found that estimates based on per capita P loads from sewage and detergent were 50% greater than Discharge Monitoring Report Pollutant Loading Tool. This suggests that the tool is likely underestimating P export in waste the CONUS scale. TP and DIP concentrations and TP yields were generally correlated more strongly with runoff than with P inputs or P balances, but even the relationships between runoff and P export were weak. Including P inputs as independent variables increased the predictive capacity of the best-fit models by at least 20%, but together inputs and runoff explained 40% of the variance in P concentration and 46–54% of the variance in P yield. By developing and applying a high-resolution P budget for the CONUS this study confirms that both hydrology and P inputs and sinks play important roles in aquatic P loading across a wide range of environments.
•Maps of 2012 terrestrial human P sources were constructed for the conterminous U.S.•Agricultural lands received 0.19 Tg more P than was harvested in major crops.•0.06 Tg P was lost to waterways as sewage and detergent.•P sources w/runoff increased linear regression fits for P concentrations & yields.•Multiple factors must be considered at once to understand P losses to waterways.
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Details
- Title
- Linking terrestrial phosphorus inputs to riverine export across the United States
- Creators
- Genevieve S Metson - National Research Council, National Academies of Science, Washington, DC, 20001, USAJiajia Lin - National Research Council, National Academies of Science, Washington, DC, 20001, USAJohn A Harrison - School of the Environment, Washington State Univ., Vancouver, WA, 98686, USAJana E Compton - Western Ecology Division, Office of Research and Development, US Environmental Protection Agency, 200 SW 35th St., Corvallis, OR, 97333, USA
- Publication Details
- Water research (Oxford), Vol.124, pp.177-191
- Academic Unit
- Harrison Research Group: Global Change and Watershed Biochemistry ; Environment, School of the (CAS)
- Publisher
- Elsevier Ltd
- Identifiers
- 99900547280201842
- Language
- English
- Resource Type
- Journal article