Release of dissolved organic matter (DOM) in an autotrophic and productive stream in Pampean region

MESSETTA, MARÍA LAURA; BUTTURINI, ANDREA; FEIJOÓ, CLAUDIA

HYDROBIOLOGIA

SPRINGER

Lugar: Berlin; Año: 2020 vol. 847 p. 2279 - 2293

0018-8158

The aim of our study was to analyze dissolved organic carbon processing at a reach of a productive Pampean stream and to determine DOM retention efficiencies under a wide range of hydrological conditions. This study was carried out in LasFlores stream, a third-order stream located in the Luja´n River basin in the northeast of the Buenos Aires province, Argentina. We selected a 2.2 km reach ofLas Flores stream. On each sampling occasion, we collected water samples at the end of the reach, at two upstream tributaries, and at the potential hydrologicalcontributors (end members) to stream flow. We determined DOC concentration and DOM optical properties in the stream and end members by combining absorbance?fluorescence spectroscopy techniques. The reach acts as a reactor for DOCconcentration at baseflow condition, when in situ production processes prevailed. However, DOC is passively transported downstream at high flowcondition. We found that humic and more degraded compounds predominate in DOM at the end of the reach. According to this, we proposed that both protein-like and humic-like compounds are produced at the study reach through in situ production processes, such as biological production from periphyton and macrophytes decomposition.