info:eu-repo/semantics/article
Retention and release of nutrients and dissolved organic carbon in a nutrient-rich stream: A mass balance approach
Fecha
2018-11Registro en:
Feijoó, Claudia Silvina; Messetta, María Laura; Hegoburu, Cecilia; Gómez Vázquez, Alicia; Guerra López, José Rodolfo; et al.; Retention and release of nutrients and dissolved organic carbon in a nutrient-rich stream: A mass balance approach; Elsevier Science; Journal Of Hydrology; 566; 11-2018; 795-806
0022-1694
CONICET Digital
CONICET
Autor
Feijoó, Claudia Silvina
Messetta, María Laura
Hegoburu, Cecilia
Gómez Vázquez, Alicia
Guerra López, José Rodolfo
Mas Pla, Josep
Rigacci, Laura Natalia
García, Victoria Julieta
Butturini, Andrea
Resumen
The relevance of fluvial systems to process nutrients and carbon is widely accepted, but their role as sinks and sources of nutrients and dissolved organic carbon (DOC) is still under discussion especially in non-forested and highly productive streams. In this study, we used a mass balance approach at a reach scale in a Pampean stream to elucidate the major sources of water, nutrients and DOC as well as to determine net in-stream retention efficiencies of nutrients and DOC under different hydrological conditions. We measured conductivity, conservative ions (chloride and calcium), soluble reactive phosphorus (SRP), nitrate (NO3), nitrite (NO2), ammonium (NH4) and DOC at the end-point of a reach of Las Flores stream (site A), at two upstream tributaries (B1 and B2), and at each potential hydrological contributors to stream flow (groundwater, overland and subsurface flows, and rainfall). In addition, we monitored one storm event where we collected samples during the rising and the recession limb of the hydrograph. Stream flow originated from groundwater (≈50%), upstream tributaries (B1 and B2) at baseflow, whereas overland flow contributed >20% during high flows. During baseflow, groundwater provided NO3 to stream water, while B2, which received a point input of a dairy industry, was the main source of SRP and NH4. Conversely, SRP and NH4 were provided by B1, overland flow and subsurface flow during high flows. Overland flow also contributed DOC during high flow periods. Mass balance estimates revealed that the reach acts as a source of DOC, SRP and NO3 (21.4, 37.4 and 53.5% mean net in-stream release, respectively) and a sink of NH4 (−36.8% mean net in-stream retention). Relevant in-stream processes may be nutrient uptake (as in the case of SRP and NH4) and biotic production (DOC), as well as decomposition (SRP) and nitrification (NH4) in this Pampean stream. Our results stress the relevance of nutrient and DOC generation processes within the channel in non-forested and highly productive streams.