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Data and R scripts for: Nutrient export and elemental stoichiometry in an urban tropical river

Authors: William McDowell · William G. McDowell · Jody Potter · Alonso Ramírez · Miguel Leon
Owners: Miguel Leon
Resource type:Composite Resource
Created:Oct 11, 2018 at 8:50 p.m.
Last updated: Nov 07, 2018 at 5:24 p.m. by Miguel Leon


R scripts presented as Jupyter Notebooks anddData to generate load and concentration estimates produced for the journal publication 'Nutrient export and elemental stoichiometry in an urban tropical river'.

An interactive version of the Jupyter Notebooks can be viewed on mybinder https://mybinder.org/v2/gh/miguelcleon/River-nutrient-exports-Puerto-Rico-/master

A prerender version of the Quebrada Sonadora Jupyter Notebook is available here https://nbviewer.jupyter.org/github/miguelcleon/River-nutrient-exports-Puerto-Rico-/blob/master/Sonadora%20%28QS%29%20flux%20and%20concentrations%202009-2014.ipynb

The journal publication abstract is presented here:

Nutrient inputs to surface waters are particularly varied in urban areas, due to multiple nutrient sources and complex hydrologic pathways. Because of their close proximity to coastal waters, nutrient delivery from many urban areas can have profound impacts on coastal ecology. Relatively little is known about the temporal and spatial variability in stoichiometry of inorganic nutrients such as silicon, nitrogen, and phosphorus (Si, N, and P) and dissolved organic matter in tropical urban environments. We examined nutrient stoichiometry of both inorganic nutrients and organic matter in an urban watershed in Puerto Rico served by municipal sanitary sewers and compared it to two nearby forested catchments using samples collected weekly from each river for 6 years. Urbanization caused large increases in the concentration and flux of nitrogen and phosphorus (2- to 50-fold), but surprisingly little change in N:P ratio. Concentrations of almost all major ions and dissolved silica were also significantly higher in the urban river than the wildland rivers. Yield of dissolved organic carbon (DOC) was not increased dramatically by urbanization, but the composition of dissolved organic matter shifted toward N-rich material, with a larger increase in dissolved organic nitrogen (DON) than DOC. The molar ratio of DOC:DON was about 40 in rivers draining forested catchments but was only 10 in the urban river. Inclusion of Si in the assessment of urbanization’s impacts reveals a large shift in the stoichiometry (Si:N and Si:P) of nutrient inputs. Because both Si concentrations and watershed exports are high in streams and rivers from many humid tropical catchments with siliceous bedrock, even the large increases in N and P exported from urban catchments result in delivery of Si, N, and P to coastal waters in stoichiometric ratios that are well in excess of the Si requirements of marine diatoms. Our data suggest that dissolved Si, often neglected in watershed biogeochemistry, should be included in studies of urban as well as less developed watersheds due to its potential significance for marine and lacustrine productivity.

Subject Keywords

urban,DON,nutrients,Puerto Rico,tropical,phosphate,dissolved organic matter,coastal,DOC,nitrate,silica,stoichiometry

How to cite

McDowell, W., W. G. McDowell, J. Potter, A. Ramírez, M. Leon (2018). Data and R scripts for: Nutrient export and elemental stoichiometry in an urban tropical river, HydroShare, http://www.hydroshare.org/resource/142c59757ed54de1816777828c9716e7

This resource is shared under the Creative Commons Attribution CC BY.


Sharing status:

  • Discoverable Resource  Discoverable
  • Sharable Resource  Shareable



 Coordinate System/Geographic Projection:  WGS 84 EPSG:4326
 Coordinate Units:  Decimal degrees


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The people or organizations that created the intellectual content of the resource.

Name Organization Address Phone Author Identifiers
William McDowell
William G. McDowell Department of Biology, Merrimack College, North Andover, MA
Jody Potter University of New Hampshire;UNH Water Quality Analysis Lab NH, US
Alonso Ramírez Department of Applied Ecology, North Carolina State University, Raleigh, NC
Miguel Leon University of Pennslyvania


This resource was created using funding from the following sources:
Agency Name Award Title Award Number
NSF EAR Luquillo Critical Zone Observatory 0722476
NSF EAR Luquillo Critical Zone Observatory 1331841
NSF DEB Luquillo LTER 0620919
NSF DEB Luquillo LTER 1239764
NSF DEB Luquillo LTER 1546686


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