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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Agriculture influences ammonium and soluble reactive phosphorus retention in South American headwater streams

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Fernandes Cunha, Davi Gasparini [1] ; Finkler, Nicolas Reinaldo [1] ; Gomez, Nora [2] ; Cochero, Joaquin [2] ; Donadelli, Jorge Luis [2] ; Saltarelli, Wesley Aparecido [1] ; Calijuri, Maria do Carmo [1] ; Poli Miwa, Adriana Cristina [1] ; Tromboni, Flavia [3] ; Dodds, Walter K. [4] ; Boechat, Iola Goncalves [5] ; Gucker, Bjorn [5] ; Thomas, Steven A. [6]
Total Authors: 13
[1] Univ Sao Paulo, Dept Hidraul & Saneamento, Escola Engn Sao Carlos, Sao Paulo, SP - Brazil
[2] Univ Nacl La Plata, Fac Ciencias Nat & Museo, Inst Limnol Dr Raul A Ringuelet, Consejo Nacl Invest Cient & Tecn, Buenos Aires, DF - Argentina
[3] Univ Nevada, Global Water Ctr, Reno, NV 89557 - USA
[4] Kansas State Univ, Div Biol, Ackert Hall, Manhattan, KS 66506 - USA
[5] Univ Fed Sao Joao del Rei, Dept Geociencias, Sao Joao Del Rei - Brazil
[6] Univ Nebraska Lincoln, Inst Agr & Nat Resources, Sch Nat Resources, Lincoln, NE - USA
Total Affiliations: 6
Document type: Journal article
Source: ECOHYDROLOGY; v. 13, n. 2 DEC 2019.
Web of Science Citations: 0

Agricultural activities can affect the delivery of nutrients to streams, riparian canopy cover, and the capacity of aquatic systems to process nutrients and sediments. There are few measures of nutrient uptake and metabolism from tropical or subtropical streams in general, and even fewer from tropical regions of South America. We examined ammonium (NH4+) and soluble reactive phosphorus (SRP) retention in streams in Brazil and Argentina. We selected 12 streams with relatively little or extensive agricultural activity and conducted whole-stream nutrient additions and measurements of gross primary production and ecosystem respiration. We used multiple linear regression to determine potential drivers of nutrient uptake metrics across the streams. Nutrient concentrations and retention differed significantly between land use categories. Both NH4+ and SRP concentrations were higher in the agricultural sites (means of 161 and 495 mu g l(-1), respectively), whereas metabolic rates were slower and transient storage was smaller. Our analysis indicated that agriculture increased ambient uptake lengths and decreased uptake velocities. The regression models revealed that ambient SRP had a positive effect on NH4+ uptake and vice versa, suggesting strong stoichiometric controls. Drivers for nutrient uptake in streams with low-intensity agriculture also included canopy cover, temperature, and ecosystem respiration rates. Nutrient assimilation in agricultural sites was influenced by a higher number of variables (gross primary production for SRP, discharge, and transient storage for both nutrients). Our results indicate agricultural activity changes both the magnitude of in-stream nutrient uptake and the mechanisms that control its variation, with important implications for South American streams under agricultural intensification. (AU)

FAPESP's process: 16/14176-1 - Macronutrient retention in Cerrado streams (SP) and its relationships with aquatic metabolism along gradients of environmental conditions: an ecosystem services' approach
Grantee:Davi Gasparini Fernandes Cunha
Support Opportunities: Regular Research Grants
FAPESP's process: 18/13171-1 - Point-source pollution effects on nutrient retention in tropical streams: experimental manipulation of stoichiometry rate of nitrogen and phosphorus
Grantee:Nícolas Reinaldo Finkler
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 17/50397-5 - Understanding the influence of land use practices and canopy cover restoration on nutrient spiraling in tropical and temperate stream ecosystems
Grantee:Davi Gasparini Fernandes Cunha
Support Opportunities: Regular Research Grants
FAPESP's process: 17/18519-3 - Structural and non-structural measures for the recovery of tropical streams: effects on aquatic metabolism and macronutrient retention
Grantee:Wesley Aparecido Saltarelli
Support Opportunities: Scholarships in Brazil - Doctorate