Scheda di dettaglio – i prodotti della ricerca

DatoValore
TitleBiotic control of in-stream nutrient retention in nitrogen-rich springs (Po Valley, Northern Italy)
AbstractAgriculture is a major contributor of nutrients to surface waters in large parts of the world and affects hydro-morphological conditions of rivers eventually altering their ecological status. Increasing attention has been given to those aspects of river functioning which refer to the processes able to modulate the concentration of nutrients exported downstream. This study aimed to evaluate the nutrient retention in agricultural groundwater-fed lowland streams, also known as "fontanili", contaminated by elevated nitrate loadings. We used the nutrient spiraling method to assess ammonium (NH4) and phosphate (PO4) retention in two fontanili reaches, that significantly differed in presence/absence of aquatic macrophytes and tree canopy in the riparian zone. The results indicate that the overall nutrient retention was higher in the macrophyte-rich than in the unvegetated stream channel. The metric better reflecting the biological removal (i.e. the uptake velocity-V-f) was 9.8-fold and 4.4-fold higher, respectively for NH4 and PO4, in the vegetated than in the unvegetated reach. Temperature was an important driver of nutrient retention in vegetated condition, while discharge explained most variation of the uptake length of both nutrients in the reach where macrophytes were lacking. The role of the autotrophic compartment was further highlighted by the positive association between the uptake velocity (V-f-NH4 and V-f-PO4) and the gross primary production. The relationships observed between some retention metrics and the relative nutrient availability suggest that primary producers strongly controlled NH4 retention despite the extremely high N:P water ratio. The median NH4 uptake rate at the macrophyte-rich spring (30.5 mu g m(-2) min(-1)) was 5.5 fold higher than that at the unvegetated one, and was in the range reported for pristine streams. A few simple management actions are suggested that might be helpful to mitigate nitrogen and phosphorous pollution in the hydraulic networks of the Po Plain.
SourceEcological engineering 122, pp. 303–314
KeywordsGroundwaterPhosphateAmmoniumUptakeMetabolismNutrient spiralling
JournalEcological engineering
EditorElsevier, New York ;, Paesi Bassi
Year2018
TypeArticolo in rivista
DOI10.1016/j.ecoleng.2018.08.014
AuthorsBalestrini, R.; Delconte, C. A.; Palumbo, M. T.; Buffagni, A.
Text400184 2018 10.1016/j.ecoleng.2018.08.014 ISI Web of Science WOS 000444616000035 Scopus 2 s2.0 85052217913 Groundwater Phosphate Ammonium Uptake Metabolism Nutrient spiralling Biotic control of in stream nutrient retention in nitrogen rich springs Po Valley, Northern Italy Balestrini, R.; Delconte, C. A.; Palumbo, M. T.; Buffagni, A. Natl Res Council CNR IRSA; Univ Tuscia Agriculture is a major contributor of nutrients to surface waters in large parts of the world and affects hydro morphological conditions of rivers eventually altering their ecological status. Increasing attention has been given to those aspects of river functioning which refer to the processes able to modulate the concentration of nutrients exported downstream. This study aimed to evaluate the nutrient retention in agricultural groundwater fed lowland streams, also known as fontanili , contaminated by elevated nitrate loadings. We used the nutrient spiraling method to assess ammonium NH4 and phosphate PO4 retention in two fontanili reaches, that significantly differed in presence/absence of aquatic macrophytes and tree canopy in the riparian zone. The results indicate that the overall nutrient retention was higher in the macrophyte rich than in the unvegetated stream channel. The metric better reflecting the biological removal i.e. the uptake velocity V f was 9.8 fold and 4.4 fold higher, respectively for NH4 and PO4, in the vegetated than in the unvegetated reach. Temperature was an important driver of nutrient retention in vegetated condition, while discharge explained most variation of the uptake length of both nutrients in the reach where macrophytes were lacking. The role of the autotrophic compartment was further highlighted by the positive association between the uptake velocity V f NH4 and V f PO4 and the gross primary production. The relationships observed between some retention metrics and the relative nutrient availability suggest that primary producers strongly controlled NH4 retention despite the extremely high N P water ratio. The median NH4 uptake rate at the macrophyte rich spring 30.5 mu g m 2 min 1 was 5.5 fold higher than that at the unvegetated one, and was in the range reported for pristine streams. A few simple management actions are suggested that might be helpful to mitigate nitrogen and phosphorous pollution in the hydraulic networks of the Po Plain. 122 Published version Biotic control of in stream nutrient retention in nitrogen rich springs Po Valley, Northern Italy ECOENG_2018.pdf Articolo in rivista Elsevier 0925 8574 Ecological engineering Ecological engineering Ecol. eng. Ecological engineering. mariateresa.palumbo PALUMBO MARIA TERESA raffaella.balestrini BALESTRINI RAFFAELLA andreastefano.buffagni BUFFAGNI ANDREA STEFANO carloandrea.delconte DELCONTE CARLO ANDREA